DZone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
Refcards Trend Reports
Events Video Library
Refcards
Trend Reports

Events

View Events Video Library

The Latest Open Source Topics

article thumbnail
What is ActiveMQ?
Although the Active MQ website already gives a pithy, to-the-point explanation of ActiveMQ, I would like to add some more context to their definition. From the ActiveMQ project’s website: “ActiveMQ is an open sourced implementation of JMS 1.1 as part of the J2EE 1.4 specification.” Here’s my take: ActiveMQ is an open-source, messaging software which can serve as the backbone for an architecture of distributed applications built upon messaging. The creators of ActiveMQ were driven to create this open-source project for two main reasons: The available existing solutions at the time were proprietary/very expensive Developers with the Apache Software Foundation were working on a fully J2EE compliant application server (Geronimo) and they needed a JMS solution that had a license compatible with Apache’s licensing. Since its inception, ActiveMQ has turned into a strong competitor of the commercial alternatives, such as WebSphereMQ, EMS/TIBCO and SonicMQ and is deployed in production in some of the top companies in industries ranging from financial services to retail. Using messaging as an integration or communication style leads to many benefits such as: Allowing applications built with different languages and on different operating systems to integrate with each other Location transparency – client applications don’t need to know where the service applications are located Reliable communication – the producers/consumers of messages don’t have to be available at the same time, or certain segments along the route of the message can go down and come back up without impacting the message getting to the service/consumer Scaling – can scale horizontally by adding more services that can handle the messages if too many messages are arriving Asynchronous communication – a client can fire a message and continue other processing instead of blocking until the service has sent a response; it can handle the response message only when the message is ready Reduced coupling – the assumptions made by the clients and services are greatly reduced as a result of the previous 5 benefits. A service can change details about itself, including its location, protocol, and availability, without affecting or disrupting the client. Please see Gregor Hohpe’s description about messaging or the book he and Bobby Woolf wrote about messaging-based enterprise application integration. There are other advantages as well (hopefully someone can add other benefits or drawbacks in the comments), and ActiveMQ is a free, open-source software that can facilitate delivering those advantages and has proven to be highly reliable and scalable in production environments.
July 21, 2012
by Christian Posta
· 28,787 Views · 8 Likes
article thumbnail
A Full Overview of the CamelOne 2012 Conference
CamelOne was yet again a really cool and fun conference. I just returned back home, from the 2nd annual CamelOne conference, held in downtown Boston. It was a 2 day packed with great talks with a balanced mix of technical talks, cloud stuff, and showcases of integration in the real world. CamelOne speaker podium The feedback of the conference was really good, as you can see from the image below. Feedback wall from CamelOne attendees The FuseSource engineering team was present, and on the end of the 2nd day, Debbie, got us together for a photo session. The FuseSource Engineering Team CamelOne 2012 - Day 1 So back the the 1st day. This year Jonathan and I was asked to do the opening key note, with our Camel story, and where the Camel project is today, and some thoughts about how Camel could be riding the cloud in the near future. Jonathan and I wanted to tell our Camel story with a sense of humor. I can say mission accomplished when the slide with the lovely Camel picture was shown. And no the picture is not retouched, it was found using google image search. Apache Camel is a project that stands out After the keynote I gave a talk about how to get started riding the Camel. The talk is a practical focus talk so I was sharing the time 50/50 between slides and live coding. As all sessions were recorded, and we can all watch them later, as they will be posted on the CamelOne website, free for anymore to watch. A professional production company is currently processing the videos. They should be ready in weeks from now. I will blog when the videos are online. Free Apache/Fuse Resources Apache Project Leader Videos Open Source Integration Tool Downloads Integrate Anywhere: Fuse ESB Super Fast Messaging with Fuse MQ Free SOA Webcasts Apache ActiveMQ and ServiceMix Lessons Integration Resources Jonathan was next after my talk, and his talk was a natural progress from mine talk. As he gave a rundown how you can run and deploy Camel and CXF applications in the ESB server. Jonathan showed how this works in practice as well. I got engaged in a number of hallway conversations, and didn't have the chance to attend a session at every slot. It was really great to meet so many happy Camel users, and hear their stories, where the Camel is riding in the real world. Also I was told that more and more commercial vendors is adapting Camel and embedding it internally in their commercial products. Kai Wahner gave his first of two talks today. Kai Wahner giving a talk about choosing Integration Frameworks He was talking about his experience with evaluating Apache Camel, Spring Integration, and Mule ESB. I guess Camel was in favor at a Camel conference :) James gave the ending general session of the first day. James Strachan giving ending key note on 1st day As always a pleasure to watch James talk with such a enthusiasm. His talk was a technical talk addressed to the developers how to develop and get Camel riding in the cloud. He gave a tour of the cool and awesome much improved Fuse IDE 2.1 product. It now has even more Camel crack for runtime insight. As well as easier deployment for both local jvms, remove machines, and as well the clouds. CamelOne 2012 - Day 2 On the 2nd day, we have Gabe Zichermann giving a very entertaining keynote, about gamification. Gabe talking about Gamification The idea of getting people engaged, based on the ideas of computer games. But applying them in a real life processes. For example a company managed to get its employees go to the gym, based on teaming up, and competing against your co-workers. In Sweden they have traffic cameras, using reverse sychology, by enlisting people in a lottery, if they are within speed limits. However people above the speed limit will of course still get a fine, and not participate in the lottery. I have heard good buzz about Stan Lewis and Dhirajs talk about how to manage, monitor and provision a cluster of machines, in a data centre or the cloud. Dhiraj showed how Fuse HQ could monitor the Camel applications running on numerous machines. And how that worked as well when Stan did a rolling upgrade on the fly, leaving Fuse HQ being able to compare and display a "before" vs. "after" overview. Likewise the tweets about Charles Moulliard were very positive. Seems like people wanted to go and play with websockets, and the Camel. This is definitly cool. So Camel 2.10 is a much anticipated release, having the websocket component out of the box. Kai was on the stage again, giving a talk about using Apache Camel with BPM (Avtiviti). Kai gave us a rundown of the differences between Camel and Activiti, and where they overlap. As well when you should use either one, or both of them. In Kais talk he give live demos which is a nice change in the flow, to see the "code" for real. Activiti and Camel together seems powerful. And the Activiti designer looks beautiful. Did you know that Camel is help protecting the Canadians. Mike Gingell from General Dynamics Canada gave us a rundown of how they have been successful by using open source integration technologies from Apache. The Camel is helping in cool stuff such as with the marine to detect torpedo attacks, with satellite surveillance of the north poles, and to keep track of personel and whatnot. Torpedo Warning System. Slide from Mike Gingell, General Dynamics Canada, Mike gave a really great talk, and also took us through how his team is battling uphill in a traditionally conservative organization where software projects take millions of $ and years to just get started. They have been on the open source road for about 5 years, and jumped on Apache ServiceMix when it became OSGi based. And the Camel has been riding all along together with ActiveMQ and CXF. So the Camel is help protecting Jonathan Anstey, who lives in New Foundland, Canada. Must be cool to know that the software he works on every day, is now serving the people of Canada. The ending keynote, was a real treat to all of us. Felix Ehmn from CERN gave us a very interesting talk how CERN is using ActiveMQ in their control room, to monitor the most complex machine man have ever built - the Large Hadron Collider; eg the 27km circle where they smash atoms together and see what happens. Felix giving ending keynote, about CERN using ActiveMQ There is 85.000 devices, which they need the monitor. Its everything, from censors on the collider, to fire alarms, door buttons and whatnot. CERN is definitily a cool place. In fact the coolest place on earth as well, as they need to cool down the collider, to 1 degree kelvin. That is - 272 degrees celsius. Like CERN, the CamelOne conference was very cool. I discovered a number of other blogs covering the CamelOne 2012 conference Kai Waehner blogged his CamelOne report. Christian Posta blogged as well And Rob Terpilowski who gave a talk also Hope to see you in 2013 at the next CamelOne conference. As David Reiser tweeted, the conference was awesome. David liked the conference
May 23, 2012
by Claus Ibsen
· 7,077 Views
article thumbnail
Martin Fowler on ORM Hate
while i was at the qcon conference in london a couple of months ago, it seemed that every talk included some snarky remarks about object/relational mapping (orm) tools. i guess i should read the conference emails sent to speakers more carefully, doubtless there was something in there telling us all to heap scorn upon orms at least once every 45 minutes. but as you can tell, i want to push back a bit against this orm hate - because i think a lot of it is unwarranted. the charges against them can be summarized in that they are complex, and provide only a leaky abstraction over a relational data store. their complexity implies a grueling learning curve and often systems using an orm perform badly - often due to naive interactions with the underlying database. there is a lot of truth to these charges, but such charges miss a vital piece of context. the object/relational mapping problem is hard . essentially what you are doing is synchronizing between two quite different representations of data, one in the relational database, and the other in-memory. although this is usually referred to as object-relational mapping, there is really nothing to do with objects here. by rights it should be referred to as in-memory/relational mapping problem, because it's true of mapping rdbmss to any in-memory data structure. in-memory data structures offer much more flexibility than relational models, so to program effectively most people want to use the more varied in-memory structures and thus are faced with mapping that back to relations for the database. the mapping is further complicated because you can make changes on either side that have to be mapped to the other. more complication arrives since you can have multiple people accessing and modifying the database simultaneously. the orm has to handle this concurrency because you can't just rely on transactions- in most cases, you can't hold transactions open while you fiddle with the data in-memory. i think that if you if you're going to dump on something in the way many people do about orms, you have to state the alternative. what do you do instead of an orm? the cheap shots i usually hear ignore this, because this is where it gets messy. basically it boils down to two strategies, solve the problem differently (and better), or avoid the problem. both of these have significant flaws. a better solution listening to some critics, you'd think that the best thing for a modern software developer to do is roll their own orm. the implication is that tools like hibernate and active record have just become bloatware, so you should come up with your own lightweight alternative. now i've spent many an hour griping at bloatware, but orms really don't fit the bill - and i say this with bitter memory. for much of the 90's i saw project after project deal with the object/relational mapping problem by writing their own framework - it was always much tougher than people imagined. usually you'd get enough early success to commit deeply to the framework and only after a while did you realize you were in a quagmire - this is where i sympathize greatly with ted neward's famous quote that object-relational mapping is the vietnam of computer science [1] . the widely available open source orms (such as ibatis, hibernate, and active record) did a great deal to remove this problem [2] . certainly they are not trivial tools to use, as i said the underlying problem is hard, but you don't have to deal with the full experience of writing that stuff (the horror, the horror). however much you may hate using an orm, take my word for it - you're better off. i've often felt that much of the frustration with orms is about inflated expectations. many people treat the relational database "like a crazy aunt who's shut up in an attic and whom nobody wants to talk about" [3] . in this world-view they just want to deal with in-memory data-structures and let the orm deal with the database. this way of thinking can work for small applications and loads, but it soon falls apart once the going gets tough. essentially the orm can handle about 80-90% of the mapping problems, but that last chunk always needs careful work by somebody who really understands how a relational database works. this is where the criticism comes that orm is a leaky abstraction. this is true, but isn't necessarily a reason to avoid them. mapping to a relational database involves lots of repetitive, boiler-plate code. a framework that allows me to avoid 80% of that is worthwhile even if it is only 80%. the problem is in me for pretending it's 100% when it isn't. david heinemeier hansson, of active record fame, has always argued that if you are writing an application backed by a relational database you should damn well know how a relational database works. active record is designed with that in mind, it takes care of boring stuff, but provides manholes so you can get down with the sql when you have to. that's a far better approach to thinking about the role an orm should play. there's a consequence to this more limited expectation of what an orm should do. i often hear people complain that they are forced to compromise their object model to make it more relational in order to please the orm. actually i think this is an inevitable consequence of using a relational database - you either have to make your in-memory model more relational, or you complicate your mapping code. i think it's perfectly reasonable to have a more relational domain model in order to simplify your object-relational mapping. that doesn't mean you should always follow the relational model exactly, but it does mean that you take into account the mapping complexity as part of your domain model design. so am i saying that you should always use an existing orm rather than doing something yourself? well i've learned to always avoid saying "always". one exception that comes to mind is when you're only reading from the database. orms are complex because they have to handle a bi-directional mapping. a uni-directional problem is much easier to work with, particularly if your needs aren't too complex and you are comfortable with sql. this is one of the arguments for cqrs . so most of the time the mapping is a complicated problem, and you're better off using an admittedly complicated tool than starting a land war in asia. but then there is the second alternative i mentioned earlier - can you avoid the problem? avoiding the problem to avoid the mapping problem you have two alternatives. either you use the relational model in memory, or you don't use it in the database. to use a relational model in memory basically means programming in terms of relations, right the way through your application. in many ways this is what the 90's crud tools gave you. they work very well for applications where you're just pushing data to the screen and back, or for applications where your logic is well expressed in terms of sql queries. some problems are well suited for this approach, so if you can do this, you should. but its flaw is that often you can't. when it comes to not using relational databases on the disk, there rises a whole bunch of new champions and old memories. in the 90's many of us (yes including me) thought that object databases would solve the problem by eliminating relations on the disk. we all know how that worked out. but there is now the new crew of nosql databases - will these allow us to finesse the orm quagmire and allow us to shock-and-awe our data storage? as you might have gathered , i think nosql is technology to be taken very seriously. if you have an application problem that maps well to a nosql data model - such as aggregates or graphs - then you can avoid the nastiness of mapping completely. indeed this is often a reason i've heard teams go with a nosql solution. this is, i think, a viable route to go - hence my interest in increasing our understanding of nosql systems. but even so it only works when the fit between the application model and the nosql data model is good. not all problems are technically suitable for a nosql database. and of course there are many situations where you're stuck with a relational model anyway. maybe it's a corporate standard that you can't jump over, maybe you can't persuade your colleagues to accept the risks of an immature technology. in this case you can't avoid the mapping problem. so orms help us deal with a very real problem for most enterprise applications. it's true they are often misused, and sometimes the underlying problem can be avoided. they aren't pretty tools, but then the problem they tackle isn't exactly cuddly either. i think they deserve a little more respect and a lot more understanding. 1: i have to confess a deep sense of conflict with the vietnam analogy. at one level it seems like a case of the pathetic overblowing of software development's problems to compare a tricky technology to war. nasty the programming may be, but you're still in a relatively comfy chair, usually with air conditioning, and bug-hunting doesn't involve bullets coming at you. but on another level, the phrase certainly resonates with the feeling of being sucked into a quagmire. 2: there were also commercial orms, such as toplink and kodo. but the approachability of open source tools meant they became dominant. 3: i like this phrase so much i feel compelled to subject it to re-use.
May 9, 2012
by Martin Fowler
· 115,769 Views · 4 Likes
article thumbnail
From Java to Node.js
I’ve been developing for quite a while and in quite a few languages. Somehow though, I’ve always seemed to fall back to Java when doing my own stuff – maybe partly from habit, partly because it has in my opinion the best open source selection out there, and party because I liked its mix of features and performance. Originally authored by Matan Amir Specifically though, in the web arena things have been moving fast and furious with new languages, approaches, and methods like RoR, Play!, and Lift (and many others!). While I “get it” regarding the benefits of these frameworks, I never felt the need to give them more than an initial deep dive to see how they work. I nod a few times at their similarities and move on back to plain REST-ful services in Java with Spring, maybe an ORM (i try to avoid them these days), and a JS-rich front-end. Recently, two factors made me deep dive into Node.js. First is my growing appreciation with the progress of the JavaScript front-end. What used to be little JavaScript snippets to validate a form “onSubmit” have evolved to a complete ecosystem of technologies, frameworks, and stacks. My personal favorite these days is Backbone.js and try to use it whenever I can. Second was the first hand feedback I got from a friend at Voxer about their success in using and deploying Node.js at real scale (they have a pretty big Node.js deployment). So I jumped in. In the short time I’ve been using it for some (real) projects, I can say that it’s my new favorite language of choice. First of all, the event-driven (and non-blocking) model is a perfect fit for server side development. While this has existed in the other languages and forms (Java Servlet 3.0, Event Machine, Twisted to name a few), I connected with the easy of use and natural maturity of it in JavaScript. We’re all used to using callbacks anyway from your typical run-of-the-mill AJAX work right? Second is the community and how large its gotten in the short time Node has been around. There are lots of useful open source libraries to use to solve your problems and the quality level is high. Third is that it was just so easy to pick up. I have to admit that my core JavaScript was decent before I started using Node, but in terms of the Node core library and feature set itself, it’s pretty lean and mean and provides a good starting point to build what you need in case you can’t find someone who already did (which you most likely can). So having said all that, I wanted to share what resources helped me get up to speed in Node.js coming from a Java background. Getting to know JavaScript There are lots of good resources out there on Node.js and i’ve listed them below. For me, the most critical piece was getting my JavaScript knowledge to the next level. Because you’ll be spending all your time writing your server code in JavaScript, it pays huge dividends to understand how to take full advantage of it. As a Java developer you’re probably trained to think in OO designs. With me, this was the part that I focused the most on. Fortunately (or unforunately), JavaScript is not a classic OO language. It can be if you shoehorn it, but i think that defeats the purpose. Here is my short list of JavaScript resources: JavaScript: The Good Parts - Definitely a requirement. Chapters 4 and 5 (functions, objects, and inheritance) are probably the most important part to understand well for those with an OO background. Learning Javascript with Object Graphs (part 2, and part 3) – howtonode.org has lots of good Node material, but this 3 part post is a good resource to top off your knowledge from the book. Simple “Class” Instantiation – Another good post I read recently. Worth digesting. Learning Node.js With a good JavaScript background, starting to use Node.js is pretty straightforward. The main part to understand is the asynchronous nature of the I/O and the need to produce and consume events to get stuff done. Here is a list of resources I used to get up to speed: DailyJS’s Node Tutorial - A multipart tutorial for Node on DailyJS’s blog. It’s a great resource and worth going through all the posts. Mixu’s Node Book - Not complete, but still worth it. I look forward to reading the future chapters. Node Beginner Book – A good starter read. How To Node – A blog dedicated to Node.js. Bookmark it. I felt that going through these was more than enough to give me the push I needed get started. Hopefully it does for you too (thanks to the authors for taking the time to share their knowledge!). Frameworks? Java is all about open source frameworks. That’s part of why it’s so popular. While Node.js is much newer, lots of people have already done quite a bit of heavy-lifting and have shared their code with the world. Below is what I think is a good mapping of popular Java frameworks to their Node.js equivalents (from what I know so far). Web MVC In Java land, most people are familiar with Web MVC frameworks like Spring MVC, Struts, Wicket, and JSF. More recently though, the trend towards client-side JS MVC frameworks like Ember.js (SproutCore) and Backbone.js reduces the required feature-set of some of these frameworks. Nonetheless, a good comparable Node.js web framework is Express. In a sense, it’s even more than a web framework because it also provides most of the “web server” functionality most Java developers are used to through Tomcat, Jetty, etc (more specifically, Express builds on top of Connect) It’s well thought out and provides the feature set needed to get things done. Application Lifecycle Framework (DI Framework) Spring is a popular framework in Java to provide a great deal of glue and abstraction functionality. It allows easy dependency injection, testing, object lifecycle management, transaction management, etc. It’s usually one of the first things I slap into a new project in Java. In Node.js… I haven’t really missed it. JavaScript allows much more flexible ways of decoupling dependencies and I personally haven’t felt the need to find a replacement for Spring. Maybe that’s a good thing? Object-Relational Mapping (ORMs) I have mixed feelings regarding ORMs in general, but it does make your life easier sometimes. There is no shortage of ORM librares for Node.js. Take your pick. Package Management Tools Maven is probably most popular build management tool for Java. While it is very flexible and powerful with a wide variety of plug-ins, it can get very cumbersome. Npm is the mainstream package manager for Node.js. It’s light, fast, and useful. Testing Framework Java has lots of these for sure, jUnit and company as standard. There are also mock libraries, stub libraries, db test libraries, etc. Node.js has quite a few as well. Pick your poison. I see that nodeunit is popular and is similar to jUnit. I’m personally testing Mocha. Testing tools are a more personal and subjective choice, but the good thing is that there definitely are good choices out there. Logging Java developers have quite a list of choices when choosing a logger library. Commons logging, log4j, logback, and slf4j (wrapper) are some of the more popular ones. Node.js also has a few. I’m currently using winston and have no complaints so far. It has the logging levels, multiple transports (appenders to log4j people), and does it all asynchronously as well. Hopefully this will help someone save some time when peeking into the world of Node. Good luck! Source: http://n0tw0rthy.wordpress.com/2012/01/08/from-java-to-node-js/
January 10, 2012
by Chris Smith
· 29,115 Views · 2 Likes
article thumbnail
Pros and Cons – When to use a Portal and Portlets instead of just Java Web-Frameworks
I had to answer the following question: Shall we use a Portal and if yes, should it be Liferay Portal or Oracle Portal? Or shall we use just one or more Java web frameworks? This article shows my result. I had to look especially at Liferay and Oracle products, nevertheless the result can be used for other products, too. The short answer: A Portal makes sense only in a few use cases, in the majority of cases you should not use one. In my case, we will not use one. What is a Portal? It is important to know that we are talking about an Enterprise Portal. Wikipedia has a good definition: „An enterprise portal [...] is a framework for integrating information, people and processes across organizational boundaries. It provides a secure unified access point, often in the form of a web-based user interface, and is designed to aggregate and personalize information through application-specific portlets.“ Several Portal server are available in the Java / JVM environment. Liferay Portal and GateIn Portal (former JBoss Portal) are examples for open source products while Oracle Portal or IBM WebSphere Portal are proprietary products. You develop Portlets („simple“ web applications) and deploy them in your portal. If you need to know more about a Portal or the Portlet JSR standards, ask Wikipedia: http://en.wikipedia.org/wiki/Portlet. Should we use a Portal or not? I found several pros and cons for using a Portal instead of just web applications. Disadvantages of using a Portal: Higher complexity Additional configuration (e.g. portlet.xml, Portal server) Communication between Portlets using Events is not trivial (it is also not trivial if two applications communicate without portlets, of course) Several restrictions when developing a web application within a Portlet Additional testing efforts (test your web applications and test it within a Portal and all its Portal features) Additional costs Open source usually offers enterprise editions which include support (e.g. Liferay) Proprietary products have very high initial costs. Besides, you need support, too (e.g. Oracle) You still have to customize the portal and integrate applications. A portal product does not give you corporate identity or systems integration for free. Software licensing often is only ten percent of the total price. Developers need additional skills besides using a web framework Several restrictions must be considered choosing a web-framework and implement the web application Rethinking about web application design is necessary Portlets use other concepts such as events or an action and render phase instead of only one phase Frameworks (also called bridges) help to solve this problem (but these are standardized for JSF only, a few other plugins are available, e.g. for GWT or Grails) Actually, IMO you have to use JSF if you want to realize Portlets in a stable, relatively „easy“ and future-proof way. There is no standard bridge for other frameworks. There are no books, best practices, articles or conference sessions about Portlets without JSF, right? Advantages of using a Portal Important: Many of the pros can be realized by oneself with relatively low efforts (see the "BUT" notes after each bullet point). Single Sign On (SSO) BUT: Several Java frameworks are available, e.g OpenSSO (powerful, but complicated) or JOSSO (not so powerful, but easy to use). Good products are available, e.g. Atlassian Crowd (I love Atlassian products such as Crowd, Jira or Confluence, because they are very intuitive and easy to use). Integration of several applications within one GUI A portal gives you layout and sequence of the applications for free (including stuff such as drag & drop, minimizing windows, and so on) Communication between Portlets (i.e. between different applications) BUT: This is required without a portal, too. Several solutions can be used, such as a database, messaging, web services, events, and so on. Even „push“ is possible for some time now (using specific web framework features or HTML 5 websockets). Uniform appearence BUT: CSS can solve this problem (the keyword „corporate identity“ exists in almost every company). Create a HTML template and include your applications within this template. Done. Personalization Regarding content, structure or graphical presentation Based on individual preferences or metadata BUT: Some of these features can be realized very easily by oneself (e.g. a simple role concept). Nevertheless, GUI features such as drag & drop are more effort (although component libraries can help you a lot). Many addons are included Search Content management Document management Web 2.0 tools (e.g. blogs or wikis) Collaboration suites (e.g. team pages) Analytics and reporting Development platforms BUT: A) Do you really need these Features? B) Is the offered functionality sufficent? Portals only offer „basic“ versions of stand-alone products. For instance, the content management system or search engine of a Portal is less powerful than other „real“ products offering this functionality. Thus, you have to think about the following central question: Do we really need all those features offered by a portal? Conclusion: The total cost of ownership (TCO) is much higher when using a portal. You have to be sure, that you really need the offered features. In some situations, you can defer your decision. Create your web applications as before. You can still integrate them in a Portal later, if you really need one. For instance, the following Oracle blog describes how you can use iFrames to do this: http://blogs.oracle.com/jheadstart/entry/integrating_a_jsf_application If you decide to use a Portal, you have to choose a Portal product. Should we use an Open Source or Proprietary Portal Product? Both, open source and proprietary Portal products have pros and cons. I especially looked at Oracle Portal and Liferay Portal, but probably most aspects can be considered when evaluating other products, too. Advantages of Oracle Portal Oracle offers a full-stack suite for development (including JSF and Portlets): Oracle Application Development Framework (ADF) Oracle JDeveloper offers good support for ADF. Everything from one product line increases efficiency (database, application server, ESB, IDE, Portal, …) – at least in theory :-) Disadvantages of Oracle Portal: High initial costs (I heard something about 200K in our company) Complex, heavyweight product (compared to Liferay Portal) Proprietary Communication between Portlets is not implemented using the standard JSR-286, but a custom proprietary solution (Source: http://www.contribute.be/web/contribute/news/-/journal_content/56_INSTANCE_pdF5/10234/21893) Advantages of Liferay Portal: Open source Drastically lower initial costs Lightwight product (1-Click-Install, etc.) Disadvantages of Liferay Portal: Not everything is from one product line (this cannot be considered as disadvantage always, but in our case the customer preferred very few different vendors (keyword “IT consolidation”) Portlets are still Portlets. Although Liferay is lightweight, realizing Portlets still sucks as it does with a proprietary product When to use a Portal? Well, the conclusion is difficult. In my opinion, it does make sense only in a few use cases. If you really need many or all of those Portal features, and they are also sufficient, then use a Portal product. Though, usually it is much easier to create a simple web application which integrates your applications. Use a SSO framework, create a template, and you are done. Your developers will appreciate not to work with Portlets and its increased complexity and restrictions. Did I miss any pros or cons? Do you have another opinion (probably, many people do???), then please write a comment and let’s discuss… Best regards, Kai Wähner (Twitter: @KaiWaehner) [Content from my Blog: Kai Wähner's Blog: Pros and Cons - When to use a Portal and Portlets instead of just Java Web-Frameworks]
October 13, 2011
by Kai Wähner DZone Core CORE
· 83,752 Views · 1 Like
article thumbnail
qcadoo MES - new Java-based Open Source manufacturing management software
Comment: Why did we do it ? For many years we stumbled upon many companies from different industries and with blushes on our cheeks, we saw that many new business software projects were solving the same problems over and over again. Every one is racing to bring new ERP systems, "innovative" CRMs and e-commerce suits. But most companies have already deployed these type of systems and optimized their sales process, finances and logistics. Little is however done with software for the manufacturing industry especially in the SME sector. Flying paper notes and Excel files - that is still the landscape in that domain. So we decided to make manufacturing management more systematic and started to work on qcadoo MES. We managed to acquire financing from the UE in the polish POIG 8.1 program and from a couple of private investors. We also build a team with people that have at least 10 year experience in developing IT solutions like ERP and BI systems for large international companies. What is qcadoo MES qcadoo MES is a manufacturing management system for small and medium companies. It combines many functions you can find in ERP, MRP and MES systems. We don't want to replace systems like SAP, MS Dynamics or Wonderware. We do not target the same groups they do. qcadoo MES lets you replace those paper notes and spreadsheets that are flying around the production line and gain benefit from having them all in one system. From the beginning of our project we had a couple of ambitious goals. First of all we wanted our software to be easy to use. From the first day we work closely with a company that specializes in usability. Thanks to this we have a clear and intuitive interface approved by eye-tracking tests. qcadoo MES should also eliminate the biggest issue with other systems of this type - starting with big and wide deployment which mess with your daily business tasks and give no guarantee of success. We did this by encapsulating every functionality - big or small - in separate modules. Modules can be turned off and on and extend functionality of other modules. Our platform takes care of everything - keeps the systems integrity and module dependencies intact. How does the user benefit from this ? He can start his adventure with qcadoo MES by deploying a simple functionality - a single module - and in time add new ones to solve just the task he needs. Additionally you don't just get access to modules from Qcadoo but mainly from our partners and from the Open Source community. Encouraged by successes of such companies like OpenERP, Open Bravo and SugarCRM we decided to also free our product on an Open Source license. We hope this will encourage developers and engineers from the manufacturing industry to collaborate with us on qcadoo MES. What makes us special You can find some manufacturing managements systems on the web. But what you wont find in them is: fully modular system - you can start from a simple functionality - one module - an add more in time. Just as your companies needs evolve. You can buy modules in the qcooStore - something similar to Apple AppStore or Android Market - but with solutions for the manufacturing industry created from day one with usability in mind - this speeds up deployments and makes user training go swiftly expandable to infinity - modules are the fundamental concept of this system and you can add new features easily without any technical knowledge. Thanks to this you can adjust our system easily to your companies specific needs. open source - our source code is available on the AGPL license which means that every one can use the software for commercial deployments (with having the terms of the AGPL in mind). Users that need more professional support and commercial modules can buy a commercial license available as a service (SaaS) - qcadoo MES is available for any browser and eliminates the need to install it manually, remembering about backups and system upgrades. This really reduces your costs and saves your time global range - from the beginning we are working on making qcadoo MES available worldwide. We are collaborating with partners from every country and believe that a wide choice of modules will fit in to production lines everywhere, Canada, Poland, India, you name it A new Module is a piece of cake - qcadoo Framework The whole system is based on the qcadoo Framework. A great tool for rapid implementation of modular database web application. Every thing in it is a module and therefore can be extended by another module. Yours for example ! While designing the qcadoo Framework we also wanted to make it very easy for new developers. For this purpose we created two simple XML languages: one to define the GUI and the other do define the data model. Thanks to them in a few lines of code you can add a new data entity, a table for it and all the basic CRUD operations (Create, Remove, Update, Delete). Also you can always write more complex business logic in a simple POJO Java class and use the XML languages to hook it to the right events. A new Application is also a piece of cake The qcadoo Framework is not limited to just manufacturing software. It's well suited for any business database application. Everywhere you need a rapid tool for data and GUI modeling, a modular architecture and a repository of business modules which you can use. Our partners ale already getting ready to use the qcadoo Framework in their commercial projects. We also hope that the open source community can benefit from it as well. About Qcadoo Limited Qcadoo Limited is a company which was founded in 2010 with the help of the UE POIG 8.1 financing program and by a couple of private investors. The core team is build from people which have years of experience in developing business software in Poland and the UE. More info on qcadoo MES and the qcadoo Framework at www.qcadoo.com
June 6, 2011
by Adam Walczak
· 6,679 Views
article thumbnail
When to Use Apache Camel?
When to use Apache Camel, a popular JVM/Java environment, and when to use other alternatives.
June 5, 2011
by Kai Wähner DZone Core CORE
· 153,378 Views · 12 Likes
article thumbnail
Solr + Hadoop = Big Data Love
Bixo Labs shows how to use Solr as a NoSQL solution for big data Many people use the Hadoop open source project to process large data sets because it’s a great solution for scalable, reliable data processing workflows. Hadoop is by far the most popular system for handling big data, with companies using massive clusters to store and process petabytes of data on thousands of servers. Since it emerged from the Nutch open source web crawler project in 2006, Hadoop has grown in every way imaginable – users, developers, associated projects (aka the “Hadoop ecosystem”). Starting at roughly the same time, the Solr open source project has become the most widely used search solution on planet Earth. Solr wraps the API-level indexing and search functionality of Lucene with a RESTful API, GUI, and lots of useful administrative and data integration functionality. The interesting thing about combining these two open source projects is that you can use Hadoop to crunch the data, and then serve it up in Solr. And we’re not talking about just free-text search; Solr can be used as a key-value store (i.e. a NoSQL database) via its support for range queries. Even on a single server, Solr can easily handle many millions of records (“documents” in Lucene lingo). Even better, Solr now supports sharding and replication via the new, cutting-edge SolrCloud functionality. Background I started using Hadoop & Solr about five years ago, as key pieces of the Krugle code search startup I co-founded in 2005. Back then, Hadoop was still part of the Nutch web crawler we used to extract information about open source projects. And Solr was fresh out of the oven, having just been released as open source by CNET. At Bixo Labs we use Hadoop, Solr, Cascading, Mahout, and many other open source technologies to create custom data processing workflows. The web is a common source of our input data, which we crawl using the Bixo open source project. The Problem During a web crawl, the state of the crawl is contained in something commonly called a “crawl DB”. For broad crawls, this has to be something that works with billions of records, since you need one entry for each known URL. Each “record” has the URL as the key, and contains important state information such as the time and result of the last request. For Hadoop-based crawlers such as Nutch and Bixo, the crawl DB is commonly kept in a set of flat files, where each file is a Hadoop “SequenceFile”. These are just a packed array of serialized key/value objects. Sometimes we need to poke at this data, and here’s where the simple flat-file structure creates a problem. There’s no easy way run queries against the data, but we can’t store it in a traditional database since billions of records + RDBMS == pain and suffering. Here is where scalable NoSQL solutions shine. For example, the Nutch project is currently re-factoring this crawl DB layer to allow plugging in HBase. Other options include Cassandra, MongoDB, CouchDB, etc. But for simple analytics and exploration on smaller datasets, a Solr-based solution works and is easier to configure. Plus you get useful and surprising fun functionality like facets, geospatial queries, range queries, free-form text search, and lots of other goodies for free. Architecture So what exactly would such a Hadoop + Solr system look like? As mentioned previously, in this example our input data comes from a Bixo web crawler’s CrawlDB, with one entry for each known URL. But the input data could just as easily be log files, or records from a traditional RDBMS, or the output of another data processing workflow. The key point is that we’re going to take a bunch of input data, (optionally) munge it into a more useful format, and then generate a Lucene index that we access via Solr. Hadoop For the uninitiated, Hadoop implements both a distributed file system (aka “HDFS”) and an execution layer that supports the map-reduce programming model. Typically data is loaded and transformed during the map phase, and then combined/saved during the reduce phase. In our example, the map phase reads in Hadoop compressed SequenceFiles that contain the state of our web crawl, and our reduce phase write out Lucene indexes. The focus of this article isn’t on how to write Hadoop map-reduce jobs, but I did want to show you the code that implements the guts of the job. Note that it’s not typical Hadoop key/value manipulation code, which is painful to write, debug, and maintain. Instead we use Cascading, which is an open source workflow planning and data processing API that creates Hadoop jobs from shorter, more representative code. The snippet below reads SequenceFiles from HDFS, and pipes those records into a sink (output) that stores them using a LuceneScheme, which in turn saves records as Lucene documents in an index. Tap source = new Hfs(new SequenceFile(CRAWLDB_FIELDS), inputDir); Pipe urlPipe = new Pipe("crawldb urls"); urlPipe = new Each(urlPipe, new ExtractDomain()); Tap sink = new Hfs(new LuceneScheme(SOLR_FIELDS, STORE_SETTINGS, INDEX_SETTINGS, StandardAnalyzer.class, MAX_FIELD_LENGTH), outputDir, true); FlowConnector fc = new FlowConnector(); fc.connect(source, sink, urlPipe).complete(); We defined CRAWLDB_FIELDS and SOLR_FIELDS to be the set of input and output data elements, using names like “url” and “status”. We take advantage of the Lucene Scheme that we’ve created for Cascading, which lets us easily map from Cascading’s view of the world (records with fields) to Lucene’s index (documents with fields). We don’t have a Cascading Scheme that directly supports Solr (wouldn’t that be handy?), but we can make-do for now since we can do simple analysis for this example. We indexed all of the fields so that we can perform queries against them. Only the status message contains normal English text, so that’s the only one we have to analyze (i.e., break the text up into terms using spaces and other token delimiters). In addition, the ExtractDomain operation pulls the domain from the URL field and builds a new Solr field containing just the domain. This will allow us to do queries against the domain of the URL as well as the complete URL. We could also have chosen to apply a custom analyzer to the URL to break it into several pieces (i.e., protocol, domain, port, path, query parameters) that could have been queried individually. Running the Hadoop Job For simplicity and pay-as-you-go, it’s hard to beat Amazon’s EC2 and Elastic Mapreduce offerings for running Hadoop jobs. You can easily spin up a cluster of 50 servers, run your job, save the results, and shut it down – all without needing to buy hardware or pay for IT support. There are many ways to create and configure a Hadoop cluster; for us, we’re very familiar with the (modified) EC2 Hadoop scripts that you can find in the Bixo distribution. Step-by-step instructions are available at http://openbixo.org/documentation/running-bixo-in-ec2/ The code for this article is available via GitHub, at http://github.com/bixolabs/hadoop2solr. The README displayed on that page contains step-by-step instructions for building and running the job. After the job is done, we’ll copy the resulting index out of the Hadoop distributed file system (HDFS) and onto the Hadoop cluster’s master server, then kill off the one slave we used. The Hadoop master is now ready to be configured as our Solr server. Solr On the Solr side of things, we need to create a schema that matches the index we’re generating. The key section of our schema.xml file is where we define the fields. These fields have a one-to-one correspondence with the SOLR_FIELDS we defined in our Hadoop workflow. They also need to use the same Lucene settings as what we defined in the static IndexWorkflow.java STORE_SETTINGS and INDEX_SETTINGS. Once we have this defined, all that’s left is to set up a server that we can use. To keep it simple, we’ll use the single EC2 instance in Amazon’s cloud (m1.large) that we used as our master for the Hadoop job, and run the simple Solr search server that relies on embedded Jetty to provide the webapp container. Similar to the Hadoop job, step-by-step instructions are in the README for the hadoop2solr project on GitHub. But in a nutshell, we’ll copy and unzip a Solr 1.4.1 setup on the EC2 server, do the same for our custom Solr configuration, create a symlink to the index, and then start it running with: Giving it a Try Now comes the interesting part. Since we opened up the default Jetty port used by Solr (8983) on this EC2 instance, we can directly access Solr’s handy admin console by pointing our browser at http://:8983/solr/admin % cd solr % java -Dsolr.solr.home=../solr-conf -Dsolr.data.dir=../solr-data -jar start.jar From here we can run queries against Solr: We can also use curl to talk to the server via HTTP requests: curl http://:8983/solr/select/?q=-status%3AFETCHED+and+-status%3AUNFETCHED The response is XML by default. Below is an example of the response from the above request, where we found 2,546 matches in 94ms. Now here’s what I find amazing. For an index of 82 million documents, running on a fairly wimpy box (EC2 m1.large = 2 virtual cores), the typical response time for a simple query like “status:FETCHED” is only 400 milliseconds, to find 9M documents. Even a complex query such as (status not FETCHED and not UNFETCHED) only takes six seconds. Scaling Obviously we could use beefier boxes. If we switched to something like m1.xlarge (15GB of memory, 4 virtual cores) then it’s likely we could handle upwards of 200M “records” in our Solr index and still get reasonable response times. If we wanted to scale beyond a single box, there are a number of solutions. Even out of the box Solr supports sharding, where your HTTP request can specify multiple servers to use in parallel. More recently, the Solr trunk has support for SolrCloud. This uses the ZooKeeper open source project to simplify coordination of multiple Solr servers. Finally, the Katta open source project supports Lucene-level distributed search, with many of the features needed for production quality distributed search that have not yet been added to SolrCloud. Summary The combination of Hadoop and Solr makes it easy to crunch lots of data and then quickly serve up the results via a fast, flexible search & query API. Because Solr supports query-style requests, it’s suitable as a NoSQL replacement for traditional databases in many situations, especially when the size of the data exceeds what is reasonable with a typical RDBMS. Solr has some limitations that you should be aware of, specifically: · Updating the index works best as a batch operation. Individual records can be updated, but each commit (index update) generates a new Lucene segment, which will impact performance. · Current support for replication, fail-over, and other attributes that you’d want in a production-grade solution aren’t yet there in SolrCloud. If this matters to you, consider Katta instead. · Many SQL queries can’t be easily mapped to Solr queries. The code for this article is available via GitHub, at http://github.com/bixolabs/hadoop2solr. The README displayed on that page contains additional technical details.
April 4, 2011
by Ken Krugler
· 119,767 Views
article thumbnail
Configuring Sonar with Maven
Sonar is an open source web-based application to manage code quality which covers seven axes of code quality as: Architecture and design, comments, duplications, unit tests, complexity, potential bugs and coding rules. Developed in Java and can cover projects in Java, Flex, PHP, PL/SQL, Cobol and Visual Basic 6. It's very efficient to navigate, offering visual reporting and you can follow metrics evolution of your project and combine them. There is an online project called Nemo dedicated to open source projects, as you can see projects like Jetty, Apache Lucene and Apache Tomcat. So, let's config Sonar to work together with Maven. First of all set up Sonar server and other configurations in Maven's settings.xml file: sonar true jdbc:postgresql://localhost/sonar org.postgresql.Driver user password http://localhost:9000 You must to have a Sonar server running and define it in sonar.host.url parameter. In this example I'm using the default Sonar URL, http://localhost:9000 , and you must set user name and password for your database. To install local Sonar Server you can see this link. After that, to execute the code analysers and save results in Sonar database just execute mvn sonar:sonar. You can config Sonar to execute in your CI (Continuous Integration) application. Hudson is a perfect match, because there is a Sonar plugin for it. See the final result below: I prefer Teamcity CI, but there isn't a stable plugin as you can see in compatibility matrix. To resolve this plugin's problem, just add sonar:sonar in the maven command executed by Teamcity. Sonar is an essential tool for your software project to help you evaluating how cohesive your classes are, warning for future problems as code complexity or duplication problems arise, and will help you to have a cleaner code. If you have any question or some difficulties, contact me.
March 21, 2011
by Valdemar Júnior
· 143,682 Views · 2 Likes
article thumbnail
Apache Solr: Get Started, Get Excited!
we've all seen them on various websites. crappy search utilities. they are a constant reminder that search is not something you should take lightly when building a website or application. search is not just google's game anymore. when a java library called lucene was introduced into the apache ecosystem, and then solr was built on top of that, open source developers began to wield some serious power when it came to customizing search features. in this article you'll be introduced to apache solr and a wealth of applications that have been built with it. the content is divided as follows: introduction setup solr applications summary 1. introduction apache solr is an open source search server. it is based on the full text search engine called apache lucene . so basically solr is an http wrapper around an inverted index provided by lucene. an inverted index could be seen as a list of words where each word-entry links to the documents it is contained in. that way getting all documents for the search query "dzone" is a simple 'get' operation. one advantage of solr in enterprise projects is that you don't need any java code, although java itself has to be installed. if you are unsure when to use solr and when lucene, these answers could help. if you need to build your solr index from websites, you should take a look into the open source crawler called apache nutch before creating your own solution. to be convinced that solr is actually used in a lot of enterprise projects, take a look at this amazing list of public projects powered by solr . if you encounter problems then the mailing list or stackoverflow will help you. to make the introduction complete i would like to mention my personal link list and the resources page which lists books, articles and more interesting material. 2. setup solr 2.1. installation as the very first step, you should follow the official tutorial which covers the basic aspects of any search use case: indexing - get the data of any form into solr. examples: json, xml, csv and sql-database. this step creates the inverted index - i.e. it links every term to its documents. querying - ask solr to return the most relevant documents for the users' query to follow the official tutorial you'll have to download java and the latest version of solr here . more information about installation is available at the official description . next you'll have to decide which web server you choose for solr. in the official tutorial, jetty is used, but you can also use tomcat. when you choose tomcat be sure you are setting the utf-8 encoding in the server.xml . i would also research the different versions of solr, which can be quite confusing for beginners: the current stable version is 1.4.1. use this if you need a stable search and don't need one of the latest features. the next stable version of solr will be 3.x the versions 1.5 and 2.x will be skipped in order to reach the same versioning as lucene. version 4.x is the latest development branch. solr 4.x handles advanced features like language detection via tika, spatial search , results grouping (group by field / collapsing), a new "user-facing" query parser ( edismax handler ), near real time indexing, huge fuzzy search performance improvements, sql join-a like feature and more. 2.2. indexing if you've followed the official tutorial you have pushed some xml files into the solr index. this process is called indexing or feeding. there are a lot more possibilities to get data into solr: using the data import handler (dih) is a really powerful language neutral option. it allows you to read from a sql database, from csv, xml files, rss feeds, emails, etc. without any java knowledge. dih handles full-imports and delta-imports. this is necessary when only a small amount of documents were added, updated or deleted. the http interface is used from the post tool, which you have already used in the official tutorial to index xml files. client libraries in different languages also exist. (e.g. for java (solrj) or python ). before indexing you'll have to decide which data fields should be searchable and how the fields should get indexed. for example, when you have a field with html in it, then you can strip irrelevant characters , tokenize the text into 'searchable terms', lower case the terms and finally stem the terms . in contrast, if you would have a field with text in it that should not be interpreted (e.g. urls) you shouldn't tokenize it and use the default field type string. please refer to the official documentation about field and field type definitions in the schema.xml file. when designing an index keep in mind the advice from mauricio : "the document is what you will search for. " for example, if you have tweets and you want to search for similar users, you'll need to setup a user index - created from the tweets. then every document is a user. if you want to search for tweets, then setup a tweet index; then every document is a tweet. of course, you can setup both indices with the multi index options of solr. please also note that there is a project called solr cell which lets you extract the relevant information out of several different document types with the help of tika. 2.3. querying for debugging it is very convenient to use the http interface with a browser to query solr and get back xml. use firefox and the xml will be displayed nicely: you can also use the velocity contribution , a cross-browser tool, which will be covered in more detail in the section about 'search application prototyping' . to query the index you can use the dismax handler or standard query handler . you can filter and sort the results: q=superman&fq=type:book&sort=price asc you can also do a lot more ; one other concept is boosting. in solr you can boost while indexing and while querying. to prefer the terms in the title write: q=title:superman^2 subject:superman when using the dismax request handler write: q=superman&qf=title^2 subject check out all the various query options like fuzzy search , spellcheck query input , facets , collapsing and suffix query support . 3. applications now i will list some interesting use cases for solr - in no particular order. to see how powerful and flexible this open source search server is. 3.1. drupal integration the drupal integration can be seen as generic use case to integrate solr into php projects. for the php integration you have the choice to either use the http interface for querying and retrieving xml or json. or to use the php solr client library . here is a screenshot of a typical faceted search in drupal : for more information about faceted search look into the wiki of solr . more php projects which integrates solr: open source typo3- solr module magento enterprise - solr module . the open source integration is out dated. oxid - solr module . no open source integration available. 3.2. hathi trust the hathi trust project is a nice example that proves solr's ability to search big digital libraries. to quote directly from the article : "... the index for our one million book index is over 200 gigabytes ... so we expect to end up with a two terabyte index for 10 million books" other examples for libraries: vufind - aims to replace opac internet archive national library of australia 3.3. auto suggestions mainly, there are two approaches to implement auto-suggestions (also called auto-completion) with solr: via facets or via ngramfilterfactory . to push it to the extreme you can use a lucene index entirely in ram. this approach is used in a large music shop in germany. live examples for auto suggestions: kaufda.de 3.4. spatial search applications when mentioning spatial search, people have geographical based applications in mind. with solr, this ordinary use case is attainable . some examples for this are : city search - city guides yellow pages kaufda.de spatial search can be useful in many different ways : for bioinformatics, fingerprints search, facial search, etc. (getting the fingerprint of a document is important for duplicate detection). the simplest approach is implemented in jetwick to reduce duplicate tweets, but this yields a performance of o(n) where n is the number of queried terms. this is okay for 10 or less terms, but it can get even better at o(1)! the idea is to use a special hash set to get all similar documents. this technique is called local sensitive hashing . read this nice paper about 'near similarity search and plagiarism analysis' for more information. 3.5. duckduckgo duckduckgo is made with open source and its "zero click" information is done with the help of solr using the dismax query handler: the index for that feature contains 18m documents and has a size of ~12gb. for this case had to tune solr: " i have two requirements that differ a bit from most sites with respect to solr: i generally only show one result, with sometimes a couple below if you click on them. therefore, it was really important that the first result is what people expected. false positives are really bad in 0-click, so i needed a way to not show anything if a match wasn't too relevant. i got around these by a) tweaking dismax and schema and b) adding my own relevancy filter on top that would re-order and not show anything in various situations. " all the rest is done with tuned open source products. to quote gabriel again: "the main results are a hybrid of a lot of things, including external apis, e.g. bing, wolframalpha, yahoo, my own indexes and negative indexes (spam removal), etc. there are a bunch of different types of data i'm working with. " check out the other cool features such as privacy or bang searches . 3.6. clustering support with carrot2 carrot2 is one of the "contributed plugins" of solr. with carrot2 you can support clustering : " clustering is the assignment of a set of observations into subsets (called clusters) so that observations in the same cluster are similar in some sense. " see some research papers regarding clustering here . here is one visual example when applying clustering on the search "pannous" - our company : 3.7. near real time search solr isn't real time yet, but you can tune solr to the point where it becomes near real time, which means that the time ('real time latency') that a document takes to be searchable after it gets indexed is less than 60 seconds even if you need to update frequently. to make this work, you can setup two indices. one write-only index "w" for the indexer and one read-only index "r" for your application. index r refers to the same data directory of w, which has to be defined in the solrconfig.xml of r via: /pathto/indexw/data/ to make sure your users and the r index see the indexed documents of w, you have to trigger an empty commit every 60 seconds: wget -q http://localhost:port/solr/update?stream.body=%3ccommit/%3e -o /dev/null everytime such a commit is triggered a new searcher without any cache entries is created. this can harm performance for visitors hitting the empty cache directly after this commit, but you can fill the cache with static searches with the help of the newsearcher entry in your solrconfig.xml. additionally, the autowarmcount property needs to be tuned, which fills the cache with a newsearcher from old entries. also, take a look at the article 'scaling lucene and solr' , where experts explain in detail what to do with large indices (=> 'sharding') and what to do for high query volume (=> 'replicating'). 3.8. loggly = full text search in logs feeding log files into solr and searching them at near real-time shows that solr can handle massive amounts of data and queries the data quickly. i've setup a simple project where i'm doing similar things , but loggly has done a lot more to make the same task real-time and distributed. you'll need to keep the write index as small as possible otherwise commit time will increase too great. loggly creates a new solr index every 5 minutes and includes this when searching using the distributed capabilities of solr ! they are merging the cores to keep the number of indices small, but this is not as simple as it sounds. watch this video to get some details about their work. 3.9. solandra = solr + cassandra solandra combines solr and the distributed database cassandra , which was created by facebook for its inbox search and then open sourced. at the moment solandra is not intended for production use. there are still some bugs and the distributed limitations of solr apply to solandra too. tthe developers are working very hard to make solandra better. jetwick can now run via solandra just by changing the solrconfig.xml. solandra also has the advantages of being real-time (no optimize, no commit!) and distributed without any major setup involved. the same is true for solr cloud. 3.10. category browsing via facets solr provides facets , which make it easy to show the user some useful filter options like those shown in the "drupal integration" example. like i described earlier , it is even possible to browse through a deep category tree. the main advantage here is that the categories depend on the query. this way the user can further filter the search results with this category tree provided by you. here is an example where this feature is implemented for one of the biggest second hand stores in germany. a click on 'schauspieler' shows its sub-items: other shops: game-change 3.11. jetwick - open twitter search you may have noticed that twitter is using lucene under the hood . twitter has a very extreme use case: over 1,000 tweets per second, over 12,000 queries per second, but the real-time latency is under 10 seconds! however, the relevancy at that volume is often not that good in my opinion. twitter search often contains a lot of duplicates and noise. reducing this was one reason i created jetwick in my spare time. i'm mentioning jetwick here because it makes extreme use of facets which provides all the filters to the user. facets are used for the rss-alike feature (saved searches), the various filters like language and retweet-count on the left, and to get trending terms and links on the right: to make jetwick more scalable i'll need to decide which of the following distribution options to choose: use solr cloud with zookeeper use solandra move from solr to elasticsearch which is also based on apache lucene other examples with a lot of facets: cnet reviews - product reviews. electronics reviews, computer reviews & more. shopper.com - compare prices and shop for computers, cell phones, digital cameras & more. zappos - shoes and clothing. manta.com - find companies. connect with customers. 3.12. plaxo - online address management plaxo.com , which is now owned by comcast, hosts web addresses for more than 40 million people and offers smart search through the addresses - with the help of solr. plaxo is trying to get the latest 'social' information of your contacts through blog posts, tweets, etc. plaxo also tries to reduce duplicates . 3.13. replace fast or google search several users report that they have migrated from a commercial search solution like fast or google search appliance (gsa) to solr (or lucene). the reasons for that migration are different: fast drops linux support and google can make integration problems. the main reason for me is that solr isn't a black box —you can tweak the source code, maintain old versions and fix your bugs more quickly! 3.14. search application prototyping with the help of the already integrated velocity plugin and the data import handler it is possible to create an application prototype for your search within a few hours. the next version of solr makes the use of velocity easier. the gui is available via http://localhost:port/solr/browse if you are a ruby on rails user, you can take a look into flare. to learn more about search application prototyping, check out this video introduction and take a look at these slides. 3.15. solr as a whitelist imagine you are the new google and you have a lot of different types of data to display e.g. 'news', 'video', 'music', 'maps', 'shopping' and much more. some of those types can only be retrieved from some legacy systems and you only want to show the most appropriated types based on your business logic . e.g. a query which contains 'new york' should result in the selection of results from 'maps', but 'new yorker' should prefer results from the 'shopping' type. with solr you can set up such a whitelist-index that will help to decide which type is more important for the search query. for example if you get more or more relevant results for the 'shopping' type then you should prefer results from this type. without the whitelist-index - i.e. having all data in separate indices or systems, would make it nearly impossible to compare the relevancy. the whitelist-index can be used as illustrated in the next steps. 1. query the whitelist-index, 2. decide which data types to display, 3. query the sub-systems and 4. display results from the selected types only. 3.16. future solr is also useful for scientific applications, such as a dna search systems. i believe solr can also be used for completely different alphabets so that you can query nucleotide sequences - instead of words - to get the matching genes and determine which organism the sequence occurs in, something similar to blast . another idea you could harness would be to build a very personalized search. every user can drag and drop their websites of choice and query them afterwards. for example, often i only need stackoverflow, some wikis and some mailing lists with the expected results, but normal web search engines (google, bing, etc.) give me results that are too cluttered. my final idea for a future solr-based app could be a lucene/solr implementation of desktop search. solr's facets would be especially handy to quickly filter different sources (files, folders, bookmarks, man pages, ...). it would be a great way to wade through those extra messy desktops. 4. summary the next time you think about a problem, think about solr! even if you don't know java and even if you know nothing about search: solr should be in your toolbox. solr doesn't only offer professional full text search, it could also add valuable features to your application. some of them i covered in this article, but i'm sure there are still some exciting possibilities waiting for you!
January 25, 2011
by Peter Karussell
· 147,545 Views
article thumbnail
Interview: Music Composer on the NetBeans Platform
Steven Yi (pictured right) is a programmer and composer living in Rochester, NY. He studied music composition in college and became a programmer afterwards. He started off as a Flash and server side developer (which he did for about 7 years), and has spent the past few years at his current company doing mobile development with J2ME, Android, and iPhone, as well as server-side development with Spring, Hibernate, etc. He started learning and using Java and Swing for personal work in 2000 and has been using it since then for the development of blue, the focus of the interview that follows below. In the interview, Steven talks about the "blue" music composer, how it works, and how the NetBeans Platform and Python form the basis of this cool open-sourced Java music composer. What's "blue"? blue is a music composition environment I started in the fall of 2000. It was actually my very first Java program! At the time, I had started using the music software Csound (http://www.csounds.com) to compose, but found it slow to work with when it came to accomplishing what I was interested in musically. I had the idea to create a simple program that would have a timeline and the ability to scale musical score material in time. Fast forward many years later: in trying to solve other musical problems, and responding to feedback from the community of users, I've expanded blue's features a great deal. It now includes things like a mixer and effects system, a GUI builder tool for creating synthesizer interfaces, embedded Jython processing of musical scripts, and more. It's been quite satisfying to create a tool that can express my musical interests and to find a community of users who have found value in this program for their own musical work. Some screenshots: The Orchestra manager shows a BlueSynthBuilder instrument being edited. The "Reson 6" instrument is shown in edit mode. The BSB Object Properties panel shows the properties for the selected knob: The Score timeline shows a project using multiple parameter automations. The values automated include things like volume, panning, and a time pointer for a phase-vocoder instrument. All BlueSynthBuilder instruments, Effects, and the Mixer volume sliders can be automated: The Score timeline showing the author's composition "Reminiscences". The timeline shows multiple Python SoundObjects used. The SoundObject Editor shows the editor for the selected SoundObject in the timeline. The SoundObject Properties panel shows different properties for the selected SoundObject: The Score timeline showing a Tracker SoundObject being used. The timeline is configured to snap at every 4 beats and the time bar has been configured to show in numbers rather than time: The Score timeline showing a PianoRoll SoundObject being used. The PianoRoll is unique in that it is microtonal, meaning it can adapt the number of steps per "octave", depending on the values configured from a tuning file. In this screenshot, the scale loaded was a Bohlen-Pierce scale, which has 13-tones per tritave (octave and a half): The blue Mixer is shown docked into the bottom bar and in an open state. The interfaces for user-created Chorus and Reverb effects are shown. The interfaces were created using the same GUI builder tool that is found in the BlueSynthBuilder instrument: It's got a very special appearance. How did that come about? blue's custom look and feel started off one day when I was using my Palm PDA. I remember thinking that I enjoyed the look of the device with the backlight on, and so I wanted to recreate that kind of look for my program. Later, I modified the color scheme to tone it down in some ways, but I also introduced more colors than white and cyan to highlight secondary and tertiary features. Maybe now it is now more like Tron than it is like Palm. :) Overall, I enjoy the darker look of the application when I'm working on music. I tend to work on music when I have free time, and that is usually only late at night—I've found having a darker screen has been easier on my eyes. Also, if anyone was wondering, yes, blue is my favorite color. The blue look and feel is encapsulated in a module named "blue-plaf" and is available in the "blue" Mercurial repository (http://bluemusic.hg.sourceforge.net/hgweb/bluemusic/blue). The look and feel is quite hacked up (redoing it properly has been another item on my todo list), but it can be dropped into another application and it should work, as shown below with the CRUD Sample (which can be created from a tutorial found here): Can you explain how blue's timeline works? blue has a concept of SoundLayers and SoundObjects. SoundObjects are objects that primarily produce notes and have a start and duration. There are many different types of SoundObjects in blue and each has an editor (viewed in the SoundObject Editor TopComponent when a SoundObject is selected), and a BarRenderer, which is used to draw the content area of the bar on the timeline. A PolyObject is a special SoundObject. It consists of SoundLayers, which contain SoundObjects. The root timeline is itself just a PolyObject that you can add as many layers to as you like. You can also group individual SoundObjects into their own PolyObjects, and then use the resulting PolyObjects just like any other SoundObject on the timeline. If you double-click a PolyObject, the timeline is then reset with the timeline of the PolyObject you selected. As a result, PolyObjects allow timelines to be embedded within other timelines. If you think about how music is grouped into motives, phrases, sections, and even larger groupings, you can see how PolyObjects might represent these kinds of musical abstractions. For the component design, the ScoreTopComponent starts off with a JSplitPane to split between a SoundLayerListPanel on the left and a JScrollPane on the right. The JScrollPane has a ScoreTimeCanvas (the main timeline) in the main viewPort's view, a panel with the the time bar and tempo editor in the column header, and the corner is used to open up an extra panel to modify properties for the timeline. The JScrollPane has customized JScrollBars used to add the ± buttons that perform zooming on the timeline. There are a number of other features involved that are implemented amongst a number of classes, but the details of how viewPorts are synchronized (among other things) may be a bit too technical to discuss here. For those who are interested, the code can be viewed within the blue.ui.core.score package within the blue-ui-core module. How did blue come to find itself atop the NetBeans Platform? I first started to be interested in NetBeans IDE around the time 4.1 came out, but didn't really get into using it until the release of 5.0. At that time, I had hand-written Swing components for about 4-5 years (I don't really remember when 5.0 was released), and I found Matisse to be quite nice and began using it here and there. I had looked at the NetBeans Platform as an RCP at that time, but found it to be quite a bit to understand. However, I still kept it on my radar. Around the time 6.0 or 6.5 came out, I started to reconsider migrating to the NetBeans Platform once again. By this time, I had moved over to using NetBeans IDE full time for blue development and had been using NetBeans IDE more in general—particularly Java Web development and Ruby on Rails. One of the biggest things I found attractive about NetBeans IDE is its windowing system... and the things I read about in the platform development articles I'd seen online made me curious once again to see what the NetBeans Platform offered. I still felt that there was going to be a big learning curve to learn the NetBeans Platform, but the NetBeans Platform tutorials online were really quite helpful, as were the members of the NetBeans Platform mailing list, and there were also many more books available to help me get started. I think I ultimately spent about 6-8 months migrating blue to using the NetBeans Platform. Granted, it was a busy time in my life and I was working on this only in my spare time, so I think in the end it was a reasonable amount of time. Users have been very positive about the new blue interface and application as a whole, and I think it has been worth spending the time to use the NetBeans Platform. blue's window layout is quite unexpected for a NetBeans Platform application. By the time I had started migrating blue to the NetBeans Platform, the application was already some 7-8 years old. The interface I designed for blue in pure Swing was influenced by my experiences in using Flash, looking at other music composition environments (Digital Audio Workstations and Sequencing Programs), and evaluating the different aspects of working with Csound. Mapping the components from the Swing-based application to the NetBeans Platform was a little tricky in that I couldn't quite get the exact same design of panels as I had in pure Swing. In the end, I tried to think about where most of the components resided physically, and created TopComponents and placed them in the center, left, right, or bottom parts of the main window. I kept some of the dialogs from the old codebase as-is, but I migrated others to be TopComponents so that they could be docked, opened, or dragged out into a dialog as the user wished. In the end, the GUI is different and took a little getting used to after years of using and building the old interface, but I quickly adjusted to the changes and I think there is much greater consistency and usability now. The users have responded very positively to the general polish of the application and to being able to customize their environment. I myself have very much enjoyed being able to dock all of the windows as well as using full-screen mode, especially when I am on my netbook and composing. Excellent! What features of the NetBeans Platform are you using and what do you find to be most useful? Currently, I am using only a very small part of the NetBeans Platform. By the time I started to move my code to the NetBeans Platform, the codebase was already some 7 or 8 years old. I took the approach recommended to me on the mailing list and started off small, focusing primarily on migrating my project to using the Windows System API, the Options API, and a few other utility API's like IO and Dialogs. Having an old codebase, I found that I spent most of my time during migration just reorganizing my UI into TopComponents and working out communications between the components. I also spent time looking at API's that I had developed myself and seeing which ones could be replaced with API's provided by the NetBeans Platform. At this time, the application is still using a number of API's I wrote from the old codebase, but over time I would like to migrate more of the appplication to use the Nodes and Visual Library API's. I think migrating a codebase of this size in phases really worked out well. In the first phase, I was able to take advantage of the Window System API and have a very visible result on the application and gained a lot for usability. Also, a big part of the migration involved moving the codebase from a monolithic source tree and partitioning it into logical modules. I think there really is a great deal of benefit to working with a codebase with modular design, and that too is a very positive result of working with the NetBeans Platform. Please say something about how Jython relates to this application, how you are using it (what the benefits are), and your general opinions on Jython. I have had a Python SoundObject in blue for quite some time—I think since 2002. For me, it is one of the most important tools in blue when it comes to accomplishing what I want musically. With computer music, we have a lot of tools for what I call Common Practice computer music: PianoRolls, Pattern Editors, and Notation Objects. For computer musicians who are interested in Uncommon Practice music, the ability to use a scripting language opens up a number of ways to express musical ideas that cannot be easily conveyed using those other tools. In blue, Jython is primarily used to allow users to write scripts that will generate notes. For myself, I use Python scripts to model orchestral composition, creating Performer and PerformerGroup objects that I write in Python. I also write performance functions, usually per-project, to perform different musical material in different ways. Other users have used Python scripts in exploring things like algorithmic composition and genetic algorithms in their work. A blue project can contain any number of Python objects. The score generated by each Python object is translated and scaled in time by moving and resizing the SoundObject in the timeline. This allows a user who may want to use scripting to create musical material to also take advantage of blue's timeline to organize how the different musical objects will work together. One of the things I most appreciate about Jython (and scripting languages on the JVM in general) is that it is embeddable within a Java application. By packaging and embedding the Jython interpreter within the blue application, users can rest assured that the Python scripts they write can be interpreted anywhere that blue is installed. It's an extra assurance that their musical projects will be long-lasting, but they can still take advantage of a full programming language like Python in their work. Overall, I think that Jython is a fine piece of software and I hope that it will continue to grow and develop for years to come. Is the application open source and are you looking for code contributions and, if so, in which areas? Yes, the application is available under the GPL v2 license, and the source code can be viewed from the Mercurial repository on SourceForge at http://bluemusic.hg.sourceforge.net/hgweb/bluemusic/blue/. I am a strong proponent of open source, especially for creative work. In the same way that we can today look at and study musical works by composers of the past (like Josquin and Bach), I would like to imagine that the work composers and other artists are now creating with computers will also be open and available for study in the future. I believe that using open source software for creative work greatly helps in making musical projects available for the years ahead. I have done most of the development of blue myself, and over the years I've certainly built up a long list of things that I would like to implement. Users have also made wonderful feature requests that I would love to see in the program—but unfortunately, there are only so many hours in the day. It would certainly be nice to have others contributing code! Beyond new features, there are a number of infrastructural things that would be nice to address. The codebase is many years old, and while the application has been refactored multiple times over its lifetime, there are still some areas of the application that could be much more cleanly implemented. Also, in moving over to the NetBeans Platforms, I only really took the first steps. There are a number of components within the application that could probably be better served by migrating to using more of the NetBeans API's. For internal work, things like modifying the timeline to implement zooming to use Graphics2d and transforms, implementing a better waveform renderer for audio files, and further enhancing the instrument GUI builder are all things I'd like to see. I'd also love to get help in migrating all of the tables and trees to using the Nodes API, something that I have not yet had the time to do. It would also be nice to get the manual (currently in HTML and PDF, generated from DocBook) integrated into the application as JavaHelp, but this is another thing that I have had to postpone due to lack of time. For features, some interesting things I'd love to see are a Notation SoundObject, a separate graphical instrument builder using the Visual Library API, and a Sampler instrument. There's also a sound drawing SoundObject, enhancements to existing SoundObjects, and more I'd love to see moving forward. Maybe someone will find these kinds of things interesting and will take a look at blue's code sometime! Thanks Steven and happy music making with blue!
May 25, 2010
by Geertjan Wielenga
· 17,979 Views
article thumbnail
Open Source NoSQL Databases
For almost a year now, the idea of "NoSQL" has been spreading due to the demand for relational database alternatives. Maybe the biggest motivation behind NoSQL is scalability. Relational databases don't lend themselves well to the kind of horizontal scalability that's required for large-scale social networking or cloud applications, and ORMs can abstract away impedance mismatch only so much. In other cases, companies just don't need as many of the complex features and rigid schemas provided by relational databases. Most people are not suggesting that we all ditch the RDBMS, in fact, many companies don't really need to switch. Relational databases will probably be necessary for many applications years and years from now. In essence, NoSQL is a movement that aims to reexamine the way we structure data and draw attention to innovation in hopes of finding the solution to the next generation's data persistence problems. Here are some of the better known open source data stores/models labeled as "NoSQL": CouchDB- Document Store Maps keys to data It provides a RESTful JSON API and is written in Erlang You can upload functions to index data and then you can call those functions Has a very simple REST interface Provides an innovative replication strategy - nodes can reconnect, sync, and reconcile differences after being disconnected for long periods of time Enables new distributed types of applications and data MongoDB - Document Store Free-form key-value-like data store with good performance Powerful, expansive query model Usability rivals that of Redis Good for complex data storage needs. Production-quality sharding capabilities Neo4j - GraphDB Disk-based Has a restricted, single-threaded model for graph traversal Has optional layers to expose Neo4j as an RDF store Can handle graphs of several billion nodes, relationships, or properties on a single machine Released under a dual license - free for non-commercial use Apache Hbase - Wide Column Store/Column Families Built on top of Hadoop, which has functionality similar to Google's GFS and MapReduce systems Hadoop's HDFS provides a mechanism that reliably stores and organizes large amounts of data Random access performance is on par with MySQL Has a high performance Thrift gateway Cascading source and sink modules Redis - Key Value/Tuple Store Provides a rich API and does more operations in memory, using disk only periodically. It's extremely fast Lets you append a value to the end of a list of items that's already been stored on a key. Has atomic operations, making it a best-of-breed tally server. Memcached - Key Value/Tuple Store High-performance, distributed memory object caching Free and open source Generic and agnostic to the objects/strings it caches It's all in-memory data Simple yet elegant design enables easy development and deployment Language neutral caching scheme. Most of the large properties on the web are using it now, except for Microsoft Project Voldemort - Eventually Consistent Key Value Store Used by LinkedIn Handles server failure transparently Pluggable serialization supports rich keys and values including lists and tuples with named fields Supports common serialization frameworks including Protocol Buffers, Thrift, and Java Serialization Data items are versioned Supports pluggable data placement strategies Memory caching and the storage system are combined Tokyo Cabinet and Tokyo Tyrant - Key Value/Tuple Store Supports hashtable mode, b-tree mode, and table mode It's fast and straightforward Good for small to medium-sized amounts of data that require rapid updating and can be easily modeled in terms of keys and values Cassandra - Wide Column Store/Column Families First developed by Facebook SuperColumns can turn a simple key-value architecture into an architecture that handles sorted lists, based on an index specified by the user. Can scale from one node to several thousand nodes clustered in different data centers. Can be tuned for more consistency or availability Smooth node replacement if one goes down ____ Some other well known NoSQL-style data stores that are closed source include Google BigTable and Amazon SimpleDB. GigaSpaces is a popular space-based Grid solution that has NoSQL qualities. Check out this informative post on NoSQL patterns.
February 23, 2010
by Mitch Pronschinske
· 46,129 Views
article thumbnail
Four Methods to Automate Development Environment Setup
There are at least four methods that can be used in different combinations to make the process of setting up a complete development environment a lot less painful.
February 16, 2010
by Mitch Pronschinske
· 31,870 Views
article thumbnail
Promiscuous Integration vs. Continuous Integration
The emergence of version control systems makes both promiscuous and continuous integration merging techniques more attractive. Which is better?
February 10, 2010
by Martin Fowler
· 50,189 Views · 2 Likes
article thumbnail
Top Open Source ESB Projects
In today's software markets, open source technologies are giving commercial products some stiff competition. Enterprise Service Busses are no exception. Don Rippert, the chief technology officer at Accenture says, "ESBs are software products that allow you to create a business process with web services running on different platforms." Rippert believes an ESB is essential for achieveing the full potential of service-oriented architecture. In general, an ESB should provide flexibility built on a basis of standards. Jos Dirksen, an author of "Open Source ESBs in Action," said in a recent interview that today's top open source ESBs were "on par with commercial alternatives." Competition drives innovation, and this page has a list of the most competitive open source ESBs on the market. Here are the the forerunners among open source ESBs (in no particular order): JBoss ESB JBoss JBoss generally has mature components in its GA releases with no vendor-lockin characteristics. Their ESB leverages JEMStechnologies like the JBoss business rules engine for content-basedrouting and messaging. Content-based routing on the JBoss ESB can use Drools or XPath. The JBoss ESB supports XSLT and the Smookstransformation engine for XML and non-XML data formats. JBoss' ESBalso runs on the JBoss application server and features a pluggable architecture for swapping out ESBsubsystems. Apache ServiceMix Apache Apache ServiceMix 4 is OSGi based and a great option for integrating with an XML standards focussed landscape. Apache ServiceMix makes it very easy to hot-deploy new integration flows. Even the pluggable integration components are hot deployable. ServiceMix uses a JBI standard which provides a lot of components like JMS, BPEL, Web service, and Camel. The inclusion of Camel is a strong point for ServiceMix along with the Spring Framework, which is also supported. FUSE ESB is another great distribution of Apache ServiceMix. OpenESB Sun(Oracle) OpenESBhas an easy learning curve due to its solid integration with theGlassFish Application Server and Sun's popular IDE, NetBeans. TheNetbeans IDE provides countless integrated functions for administrationand development. The best thing about OpenESB is its toolset. OpenESB's tools include WSDL and schema editors, a JPI manager integrated into the service manager, and Antrunning in the background. Another tool is the Composite ApplicationService Assembly (CASA) editor, which gives you a graphical overview ofintegration applications. Many Java developers will love OpenESBbecause it comes straight from the home of Java. OpenESB is also OSGi based. MuleESB MuleSoft Mule is the most used open source integration platform. MuleESB's low cost along with easy configuration, expansion, and flexibility make it very popular. Java developers will find MuleESB easy to work with because it is Java centric. There’s also a powerful set of XML schemas in MuleESB. The creation of integration flows is very straightforward. MuleESB can have fairly complex integration flows up and running in minutes. It has many connectivity, routing, and transformation options right out of the box. WSO2 ESB WSO2 Other ESB products take a relatively heavyweight approach by using the JBI specification, but the relative newcomer, WSO2, takes a lightweight approach in its ESB. It does this by focusing on Web service standards for integration. The WSO2 ESB uses Apache Synapse, a nimble Web service mediation and routing engine that focuses on providing fast XML message processing. WSO2 takes advantage of Synapse's non-blocking http://s transport implementation over the Apache HttpComponents/NIO module. This allows the WSO2 ESB to handle thousands of parallel requests using a small amount of resources and threads. You can always expect great XML support from the WSO2 ESB because well-known XML expert James Clark is a company director at WSO2.
October 29, 2009
by Mitch Pronschinske
· 241,745 Views
article thumbnail
Top 10 Open Source Projects for .NET Developers
There are many useful, practically essential, open source solutions available to .NET developers. This is a list of the ones that have been the most useful in my experience. Agree? Disagree? Leave a comment with your own suggestions. NHibernate - NHibernate is a mature, open source object-relational mapper for the .NET framework. It's actively developed, fully featured and used in thousands of successful projects. http://nhforge.org/Default.aspx NUnit - NUnit is a unit-testing framework for all .Net languages. Initially ported from JUnit, the current production release, version 2.4, is the fifth major release of this xUnit based unit testing tool for Microsoft .NET. It is written entirely in C# and has been completely redesigned to take advantage of many .NET language features, for example custom attributes and other reflection related capabilities. NUnit brings xUnit to all .NET languages. http://www.nunit.org/index.php jQuery - jQuery is a fast and concise JavaScript Library that simplifies HTML document traversing, event handling, animating, and Ajax interactions for rapid web development. jQuery is designed to change the way that you write JavaScript. http://jquery.com/ Rhino.Mocks - A dynamic mock object framework for the .Net platform. It's purpose is to ease testing by allowing the developer to create mock implementations of custom objects and verify the interactions using unit testing. http://ayende.com/projects/rhino-mocks.aspx MVC Contrib - This is the contrib project for the ASP.NET MVC framework. This project adds additional functionality on top of the MVC Framework. These enhancements can increase your productivity using the MVC Framework. It is written in C#. Founded by Eric Hexter and Jeffrey Palermo. http://www.codeplex.com/MVCContrib CruiseControl.NET - CruiseControl.NET is an Automated Continuous Integration server, implemented using the Microsoft .NET Framework. http://confluence.public.thoughtworks.org/display/CCNET/Welcome+to+CruiseControl.NET S#arp Architecture - Pronounced "Sharp Architecture," this is a solid architectural foundation for rapidly building maintainable web applications leveraging the ASP.NET MVC framework with NHibernate. The primary advantage to be sought in using any architectural framework is to decrease the code one has to write while increasing the quality of the end product. A framework should enable developers to spend little time on infrastructure details while allowing them to focus their attentions on the domain and user experience. http://code.google.com/p/sharp-architecture/ Spark View Engine - Spark is a view engine for Asp.Net Mvc and Castle Project MonoRail frameworks. The idea is to allow the html to dominate the flow and the code to fit seamlessly. http://sparkviewengine.com/ TortoiseSVN - A Subversion client, implemented as a windows shell extension. TortoiseSVN is a really easy to use Revision control / version control / source control software for Windows. Since it's not an integration for a specific IDE you can use it with whatever development tools you like. TortoiseSVN is free to use. You don't need to get a loan or pay a full years salary to use it. http://tortoisesvn.tigris.org/ Castle Windsor - Castle Project offers two Inversion of Control Containers. The MicroKernel and the Windsor Container. Castle Windsor aggregates the MicroKernel and exposes a powerful configuration support. It is suitable for common enterprise application needs. It is able to register facilities and components based on the configuration and adds support for interceptors. http://www.castleproject.org/container/index.html
May 4, 2009
by Alvin Ashcraft
· 88,320 Views
article thumbnail
Enterprise Integration Patterns with Apache Camel Refcard Now Available!
Apache Camel is a powerful open source integration platform based on Enterprise Integration Patterns with Bean Integration. This Refcard provides you with eleven of the most essential patterns that anyone working with integration must know. This Refcard is targeted for software developers and enterprise architects, but anyone in the integration space can benefit as well. Download Now! About the Author: Claus Ibsen is a passionate open-source enthusiast who specializes in the integration space. As an engineer in the FuseSource Open Source Division he works full time on Apache Camel, FUSE Mediation Router (Apache Camel Enterprise) and related projects. Claus is very active in the Apache Camel and Fuse communities, writing blogs, twittering, assisting on the forums, irc channels and is driving the Apache Camel roadmap.
March 30, 2009
by Wei Ling Chen
· 5,046 Views
article thumbnail
Performance Monitoring Using Glassbox
The industry is recognizing the fact that performance testing & engineering should be part of the project execution road map starting from the requirements gathering phase. At many times during project executions, performance engineering related activities are executed based on customer need or slow response time of application after development phase gets completed. Glassbox can be leveraged (by developers/testers/business users) during and after the development cycle to monitor the response times of requests with-out being aware of underlying application structure and code details. Analysis generated by Glassbox gives direct pointers on where is the bottleneck which causes slow response time for that particular request/page/URL. About Glassbox Glassbox is an open source web application which aid in performance monitoring and troubleshooting of multiple web applications deployed in container. Troubleshooting It contains the built-in knowledge repository of common problems which are used to pinpoint the issues and suggestions on causes as Java code executes. Performance Monitoring It monitors the requests as Java code executes and provides details about response times. Glassbox web client (AJAX GUI) provides nice summary dashboard view which contains various attributes like (server-name, application name, operation/request-URL, average time, no. of executions, status (slow / OK) and analysis details). By default, an operation that takes more than 1 sec execution time is marked as SLOW status. Such SLA can be modified using Glassbox properties file. Analysis part describes the problem precisely and very clearly in plain English words, rather than displaying large code/exception trace. This definitely increases developer productivity by reducing developer’s time spent in log files and using IDE debuggers. Internals The two main components of Glassbox are Monitor and Agent. Monitor uses Aspect-Oriented Programming (AOP) to monitor the JVM activity. Agent diagnoses and presents the monitoring results and uses knowledge repository to cross reference the problem with suggestions/solutions. Glassbox agent supports viewing of the analysis results using JMX (eg. Java 5 JConsole) Consoles. Glassbox extensively uses the AOP approach internally to monitor the Java code. This gives the benefit of not making any changes to source code or build-process and hence can work with any legacy web application/jar file as well. Technologies Glassbox should work on any application server that supports Servlet 2.3 or later. The servers where Glassbox is tested and installation process is automated are Apache Tomcat, weblogic, websphere, Resin, Oracle OC4J, websphere, Resin, Jetty & GlassFish. Overhead Having Glassbox application running on same container would generate a performance overhead. Typically this would affect the response time and memory overhead. Hence it is recommended to start the Glassbox application only when it’s required for performance monitoring. Licensing Glassbox is an open source project, it is free to download and run. Glassbox uses the GNU Lesser General Public License to distribute software and documentation. Demo Application Development & Deployment to Tomcat To test the capabilities of Glassbox, a sample application is developed which has a TestServlet class. This servlet calls DelayGenerator class’s generateDelay() method. This method calls Thread class’s sleep() method which suspends the execution of servlet. A counter is being initialized in DelayGenerator class which determines the time interval till which servlet is needed to be suspended. TestServlet.java /** * File: TestServlet.java * @author Viral Thakkar */ package com.infosys.star.glassbox; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class TestServlet extends HttpServlet { protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { DelayGenerator delayObj = new DelayGenerator(); int delay = delayObj.generateDelay(); response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println(""); out.println(" Hello World from Test Servlet : "+delay+" milliseconds "); out.println(""); out.flush(); } } DelayGenerator.java /** * File: DelayGenerator.java * @author Viral Thakkar */ package com.infosys.star.glassbox; public class DelayGenerator { private static int counter = 1; public int generateDelay() { try { Thread.sleep(counter * 100); counter++; } catch (InterruptedException e) { e.printStackTrace(); } return counter*100; } } Glassbox Installation & Integration to Apache Tomcat 6.0 Glassbox installation is very straightforward for non-clustered environment for the server where it’s automated. Simply drop the glassbox.war file at the appropriate folder inside server folder or perform the server specific steps/configuration to deploy the war file. Browse to server url with context root as glassbox – http://<>:/glassbox. Follow the instructions available on this page. According to specific server, this page would suggest the configuration changes for a server. Please refer to Glassbox User Guide document for details on how to install Glassbox for clustered application server environment. For Apache Tomcat 6.0- Add following command line arguments to Tomcat’s Java options: -Dglassbox.install.dir=C:\Tomcat6.0\lib\glassbox -Djava.rmi.server.useCodebaseOnly=true -javaagent:C:\Tomcat6.0\lib\aspectjweaver.jar Monitoring & Technical Analysis Glassbox web client (URL- http://<>:<>/glassbox ) shows the summary and detailed view of all the requests/operations that container/JVM has executed. Summary Section View Different attributes (columns) which gets displayed in this table are as below - Attribute / Column Name Comments Status This indicates whether operation/request is performing OK, SLOW or FAILING Analysis For SLOW/FAILING status, this value provides the small summary of the cause of the problem. Operation This is name of the operation/request of an application Server Name of the server where monitoring is being done. In a clustered environment, this allows to distinguish operations on different servers. Executions This value indicates how many times this operation has run since the application server was started or Glassbox’s statistics were last reset. Click the request in above summary table to view its detailed analysis in below detailed section. Detailed Section View The details area provides information relating to operations selected in the summary table. Different sub-sections which gets displayed in this view are as below - Sub-section Name Comments Executive Summary High level summary view of the selected operation gets displayed in a table format. This is neat view to senior stake holders who are not interested in technical details. Technical Summary This section contains more technical details in paragraph and table representation formats to provide insight into root cause of the problem if any, like which operation, query is slow and statistics of same. Details like stack trace, thread lock name are provided to find and fix the problem. “Common solutions” sub section shows pointers to resolve the identified problem/s. “Glassbox has ruled out other potential problems” sub section saves time to know what problems have already been ruled out. Executive Summary View Technical Summary -> Technical Details Views Above two snapshots are parts of the Technical Details section and provide minute details at code level with line number so as to pinpoint where the problem is. Here cause is identified at Class com.infosys.star.glassbox.DelayGenerator inside Method generateDelay at line number 12 where Thread.sleep is invoked. Perform Load Testing Using JMeter and Monitor Using Glassbox Apache JMeter is used to test performance both on static and dynamic resources (files, Servlets, Perl scripts, Java Objects, Data Bases and Queries, FTP Servers and more). It can be used to simulate a heavy load on a server, network or object to test its strength or to analyze overall performance under different load types. It can be used to make a graphical analysis of performance or to test server/script/object behavior under heavy concurrent load. Using JMeter, create a test plan that simulates 10 users requesting for 1 page 5 times. i.e. 10 x 1 x 5 = 50 HTTP requests. First step is to add a Thread Group element. The Thread Group tells JMeter the number of users to simulate, how often the users should send requests, and the how many requests they should send. Next step is to add HTTP Request element to added Thread Group. In parallel, have the Glassbox up and running to monitor response time statistics of the load generated by JMeter application. Below is the Executive summary view of above test in Glassbox web UI interface. Section “Monitoring & Technical Analysis” contains the details to understand the Glassbox generated analysis. Conclusion Glassbox is not the replacement for performance testing tool like load runner. Glassbox aids in the project to various stakeholders in finding, conveying and fixing the performance problems at all phases starting build (development) to post deployment. Glassbox application to be started/installed only during monitoring time so as to avoid the performance overhead for other applications due to CPU & memory footprint occupied by Glassbox application on the container. During load testing of the application, Glassbox turns out to be good option to figure out the root causes inside an application code. References Glassbox web site - http://www.glassbox.com/glassbox/Home.html Glassbox User Guide - http://nchc.dl.sourceforge.net/sourceforge/glassbox/Glassboxv2.0UserGuide.pdf Apache JMeter - http://jakarta.apache.org/jmeter/ Download & Support Glassbox Download Link - http://www.glassbox.com/glassbox/Downloads.html Glassbox forum Link - http://sourceforge.net/forum/forum.php?forum_id=575670 About Author Viral Thakkar is a Technical Architect with the Banking and Capital Markets vertical at Infosys. He has 9.5 years of technology consulting experience mainly on Java/JEE technologies and frameworks with large banks and financial institutions across the globe. He has been part of many small and large-scale initiatives related to application development, architecture creation and strategy definition. From http://viralpatel.net/blogs
March 5, 2009
by Viral Thakkar
· 20,763 Views
article thumbnail
Open Source : How Do You Stay Up To Date?
I Love the concepts and beliefs behind Open Source. I use Open Source libraries, applications etc. all the time. One of the things I have always found a challenge though, is knowing when a new release comes to be. Not only that, is this a simple point release, a major release or a security release. For the most part I want to stay up to date, especially with the libraries I use, when a security releases is made. Currently I play the, I hope I have the most stable, most secure version. Howeaver, I always thought that having a single place that I can sign-up to be informed about releases would be awesome. Do you have a way to do this or, are you subscribing to a multitude of RSS feeds and mailing lists to stay informed?
January 10, 2009
by Schalk Neethling
· 5,189 Views
article thumbnail
The Three Pillars of Continuous Integration
Continuous Integration commonly known as CI is a process that consists of continuously compiling, testing, inspecting, and deploying source code. In any typical CI environment, this means running a new build every time code changes within a version control repository. Martin Fowler describes CI as: A software development practice where members of a team integrate their work frequently, usually each person integrates at least daily - leading to multiple integrations per day. Each integration is verified by an automated build to detect integration errors as quickly as possible. Many teams find that this approach leads to significantly reduced integration problems and allows a team to develop cohesive software more rapidly. While CI is actually a process, the term Continuous Integration often is associated with three important tools in particular. As shown in the image the three pillars of CI are: 1. A version control repository like Subversion, or CVS. 2. A CI Server such as Hudson, or Cruise Control 3. An automated build process like Ant or Nant So, let’s look at each of these in detail: Version Control Repository: Version control repositories also known as SCM (source code management) play a crucial role in any software development environment. They also play a very important role for a successful CI process. The SCM is a central place for the team to store every needed artifact for the project. It is mandatory for the teams to put everything needed for a successful build into this repository. This includes the build scripts, property files, database scripts, all the libraries required to build the software and so on. The CI Server: For CI to function properly, we also need to have an automated process that monitors a version control repository and runs a build when any changes are detected. There are several CI servers available, both open source and commercial. Most of them are similar in their basic configuration and monitor a particular version control repository and run builds when any changes are detected. Some of the most commonly used open source CI servers are; Cruise Control, Continuum, and Hudson. Hudson is particularly interesting because of its ease of configuration and compelling plug-ins, which makes integration with test and static analysis tools much easier. Automated Build: The process of CI is about building software often, which is accomplished through the use of a build. A sturdy build strategy is by far the most important aspect of a successful CI process. In the absence of a solid build that does more than compile your code, CI withers. With automated builds, teams can reliably perform (in an automated fashion) otherwise manual tasks like compilation, testing, and even more interesting things like software inspection and deployment. Now that we have seen the important tools in our CI process, let’s see how a typical CI scenario looks like for a developer: CI server is configured to poll the version control repository continuously for changes. Developer commits code to the repository. CI server detects this change, and retrieves the latest code from the repository. This causes the CI server to invoke the build script with the given targets and options. If configured, CI Server will send out an e-mail to the specified recipients when a certain important event occurs. The CI server continues to poll for changes. Why is CI Important? This is one of the most frequently asked questions, and here are a few points to note about this powerful technique: Building software often greatly increases the likelihood that you will spot defects early, when they still are relatively manageable. Extends defect visibility. CI ensures that you have production ready software at every change. CI also ensures that you have reduced the risk of integration issues by building software at every change. CI server can also be configured to run continuous inspection which can assist the development team in finding potential bugs, bad programming practice, automatically check coding standards, and also provide valuable feedback on the quality of code being written. Over the past several months, I have assisted several companies in implementing CI. There was a little bit of resistance from the developers in the early stages when we implemented continuous feedback. But, never heard a single negative comment about this approach. If you already have a version control repository and automated builds, you are very close to the CI process. Download one of the open source CI servers, configure and setup a simple project. It should take less than an hour if you have automated build scripts. Start adding additional features like code inspections, generating reports, metrics, documentation and so on. Most important, send continuous feedback to your team. Give this process a try, you sure will be surprised to see how effective it is. And, as always share your thoughts, concerns or questions.
December 15, 2008
by Meera Subbarao
· 24,049 Views
  • Previous
  • ...
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • Next
  • RSS
  • X
  • Facebook

ABOUT US

  • About DZone
  • Support and feedback
  • Community research

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • Become a Contributor
  • Core Program
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 3343 Perimeter Hill Drive
  • Suite 215
  • Nashville, TN 37211
  • [email protected]

Let's be friends:

  • RSS
  • X
  • Facebook
×