Time to talk about creating new classes at runtime in Groovy. There seems to be some fear, uncertainty and doubt about memory leaks and evaluating code with Groovy in the form of calling an eval() method. The code that seems to cause consternation is this: def shell = new GroovyShell() 1000.times { shell.evaluate "x = 100" } The groovy.lang.GroovyShell instance will call the parseClass() method on an internal groovy.lang.GroovyClassLoader instance, which will create a 1000 new classes. The classes will all extend the groovy.lang.Script class. With every new Class created a little bit more memory will be used. As long as the groovy.lang.GroovyShell instance and thus its internal groovy.lang.GroovyClassLoader instance is not garbage collected this memory will remain occupied, even if you don't keep a reference to these classes. This is standard Java ClassLoader behavior. So, how to solve this problem? Well, ClassLoaders in Java are somewhat hard to handle, but it's not so hard once you understand how they work. But lets also consider the root of the problem, namely the fact that Groovy creates a new Class for each script that is evaluated. Before answering why Groovy always creates new Class objects when evaluating code let's first try to fix the code above. One way to fix it is this: def shell = new GroovyShell() 1000.times { shell.evaluate "x = 100" } shell = null By setting the shell variable to null, will the GroovyClassLoader instance be garbage collected? We can guarantee it will in this bit of code. But then again this code does not do anything useful :-) Here's another way to fix it: def shell = new GroovyShell() def script = shell.parse "x = 100" 1000.times { script.run() } By evaluating - parsing - the code only once and calling the run() method on the groovy.lang.Script instance a 1000 times we only use 1/1000th of the memory :-) The parse() method returns a groovy.lang.Script instance. But again, let's consider a more realistic use case. After all, the article that originally critized Groovy for causing memory leaks implies that evaluating code any number of times is a valid requirement in entreprise applications. Let's say it's more of a corner case but still, the functionality is there and it can solve real-world problems. Evaluating Groovy code may be particularly useful and critical when evaluating code on demand. This could happen when an application reads code from file or a database to execute custom business logic. Let's consider the case where developers create a DSL or Domain Specific Language like this: assert customer instanceof Customer assert invoice instanceof Invoice letterHead { customer { name = customer.name address { line1 = "${customer.streetName}, ${customer.streetNumber}" line2 = "${customer.zipCode} ${customer.location}, ${customer.state}" } } invoiceSummary { number = invoice.id creationDate = invoice.createdOn dueDate = invoice.payableOn } } To parse this DSL developers wrote this code (using the iText PDF library): import com.lowagie.text.* import com.lowagie.text.pdf.* class LetterHeadFormatter { static byte[] createLetterHeadForInvoice(Customer cust, Invoice inv, String dsl) { Script dslScript = new GroovyShell().parse(dsl) dslScript.binding.variables.customer = cust dslScript.binding.variables.invoice = inv Document doc = new Document(PageSize.A4) def out = new ByteArrayOutputStream() PdfWriter writer = PdfWriter.getInstance(doc, out) doc.open() dslScript.metaClass = createEMC(writer, dslScript) dslScript.run() doc.close() return out.toByteArray() } static ExpandoMetaClass createEMC(PdfWriter writer, Script script) { ExpandoMetaClass emc = new ExpandoMetaClass(script.class, false) emc.letterHead = { Closure cl -> PdfContentByte content = writer.directContent cl.delegate = new LetterHeadDelegate(content) cl.resolveStrategy = Closure.DELEGATE_FIRST cl() } emc.initialize() return emc } } (Check the attachements of this article to download this code. Read the README.txt file if you want to run the load test yourself, and please report back the results. Also, check the PDF file for the output of the DSL.) On line 6 the parse() method is called. I wrote a load test that calls the createLetterHeadForInvoice() method 1 million (!) times (with regular calls to System.gc()). On my Windows XP machine, when I run the load test with Ant the java process memory usage fluctuates between 32 and 37Mb and remains stable over the course of several hours. Are the GroovyShell and internal GroovyClassLoader instances garbage collected? Yes they are. Is there a memory leak? No. So why does Groovy create Classes when evaluating scripts? Every bit of code in Groovy is a java.lang.Class. This means that it's loaded by a java.lang.ClassLoader and remains in memory unless the ClassLoader can be garbage collected. Why isn't a Class object garbage collected as soon as it's no longer used? Why does the ClassLoader itself have to be garbage collected before the classes it has loaded are removed from memory? If classes would be automatically discarded and reloaded their static variables and static initialization would be executed on each reload. That would be quite surprising and unpredictable. That's why ClassLoaders have to keep hold of their classes, to assure predictable behavior. There may be other technical reasons, but this is the most obvious one. Once the ClassLoader object itself gets garbage collected (because it's no longer referenced in any stack) the garbage collector will attempt to unload all its Class objects. Obviously, creating a lot of classes at runtime in the same ClassLoader will increase the memory usage and will typically create a memory leak. On the other hand, since every Groovy class is a real Java Class (without exception) you don't have to make the distinction. In conclusion: there is no memory leak in GroovyShell or GroovyClassLoader. Download the sample code and verify for yourself. Your code can create a memory leak by the way ClassLoaders are used - either explicitly by your code or implicitly.

Sometimes you need special measures. Not to make Groovy work, but to make your applications or frameworks a little bit more powerful or versatile.

This turns a class name (like LineItem) into a nice string (like "line item") line_item = LineItem.new puts line_item.class.name.underscore.humanize.lowcase #spits out "line item"

// Groovy Method to perform word-wrap to a specified length. // Returns a List of strings representing the wrapped text // Quick and Dirty method for plain text word-wrap to a specified width static class TextUtils { static String[] wrapntab(input, linewidth = 70, indent = 0) throws IllegalArgumentException { if(input == null) throw new IllegalArgumentException("Input String must be non-null") if(linewidth <= 1) throw new IllegalArgumentException("Line Width must be greater than 1") if(indent <= 0) throw new IllegalArgumentException("Indent must be greater than 0") def olines = [] def oline = " " * indent input.split(" ").each() { wrd -> if( (oline.size() + wrd.size()) <= linewidth ) { oline <<= wrd <<= " " }else{ olines += oline oline = " " * indent } } olines += oline return olines } } // TEST // the input String input = "Note From SUPPLIER: Booking confirmed by fax. 4 standard rooms - 3 twin shared, 1 single room, please advise if guests require meals.. " // call static wrapntab method to break the input string into 70 char wide lines with a 4 char initial indent olines = TextUtils.wrapntab(input,70,4) // print the output olines.each() { println it }

The code below gets all classes within a given package. Notice that it should only work for classes found locally, getting really ALL classes is impossible. /** * Scans all classes accessible from the context class loader which belong to the given package and subpackages. * * @param packageName The base package * @return The classes * @throws ClassNotFoundException * @throws IOException */ private static Class[] getClasses(String packageName) throws ClassNotFoundException, IOException { ClassLoader classLoader = Thread.currentThread().getContextClassLoader(); assert classLoader != null; String path = packageName.replace('.', '/'); Enumeration resources = classLoader.getResources(path); List dirs = new ArrayList(); while (resources.hasMoreElements()) { URL resource = resources.nextElement(); dirs.add(new File(resource.getFile())); } ArrayList classes = new ArrayList(); for (File directory : dirs) { classes.addAll(findClasses(directory, packageName)); } return classes.toArray(new Class[classes.size()]); } /** * Recursive method used to find all classes in a given directory and subdirs. * * @param directory The base directory * @param packageName The package name for classes found inside the base directory * @return The classes * @throws ClassNotFoundException */ private static List findClasses(File directory, String packageName) throws ClassNotFoundException { List classes = new ArrayList(); if (!directory.exists()) { return classes; } File[] files = directory.listFiles(); for (File file : files) { if (file.isDirectory()) { assert !file.getName().contains("."); classes.addAll(findClasses(file, packageName + "." + file.getName())); } else if (file.getName().endsWith(".class")) { classes.add(Class.forName(packageName + '.' + file.getName().substring(0, file.getName().length() - 6))); } } return classes; }

EZ drop in backup rake task for your rails projects - works well - 5 - 10 min set up, one rake file and one config file backs up db and any directory's to any number of servers with rsync BSD License or whatever, but it would be cool if you told me your using it 2007 ISS http://industrialstrengthinc.com this is a sample config file and a rake task you can drop into any rails project to do backups, easy to automate. Backs up your specified environment db to activerecord yml files (one per table) and zips them up in a human readable timestamped file syncs that and any other set of arbitrary directory's to any number of arbitrary servers with rsync be sure to set ssh key based logins to run: rake backup also: rake backup:db, rake backup:restoredb (promts for a file created by backup:db), rake backup:push (to push out what u got) note: this uses something like 30 lines of code from some blog site I got it from that I cant recall, yay for that guy, thanks ## example crontab entry: 3 * * * * cd /rails_deployment_dir/current && nice rake backup RAILS_ENV=production >> /rails_deployment_dir/production_backup_system.log ## config file - goes in config/backup.yml production: dirs: - db/backups - public/uploaded_images servers: - name: backup server number 1 host: gridserver.com port: 22 user: [email protected] dir: /home/blah/backups - name: backup server two host: kradradio.com port: 22 user: kraduser dir: /home/kraduser/backups_from_my_rails_proj development: dirs: - db/backups - public/uploaded_images servers: - name: local self host: localhost port: 5222 user: oneman dir: /home/oneman/Documents/development_backup ## rake file lib/tasks/backup.rake desc "Backup Everything Specified in config/backup.yml" task :backup => [ "backup:db", "backup:push"] namespace :backup do RAILS_APPDIR = RAILS_ROOT.sub("/config/..","") def interesting_tables ActiveRecord::Base.connection.tables.sort.reject! do |tbl| ['schema_info', 'sessions', 'public_exceptions'].include?(tbl) end end desc "Push backup to remote server" task :push => [:environment] do FileUtils.chdir(RAILS_APPDIR) backup_config = YAML::load( File.open( 'config/backup.yml' ) )[RAILS_ENV] for server in backup_config["servers"] puts "Backing up #{RAILS_ENV} directorys #{backup_config['dirs'].join(', ')} to #{server['name']}" puts "Time is " + Time.now.rfc2822 + "\n\n" for dir in backup_config["dirs"] local_dir = RAILS_APPDIR + "/" + dir + "/" remote_dir = server['dir'] + "/" + dir.split("/").last + "/" puts "Syncing #{local_dir} to #{server['host']}#{remote_dir}" sh "/usr/bin/rsync -avz -e 'ssh -p#{server['port']} ' #{local_dir} #{server['user']}@#{server['host']}:#{remote_dir}" end puts "Completed backup to #{server['name']}\n\n" end end task :storedb => :environment do backupdir = RAILS_APPDIR + '/db/backup' FileUtils.mkdir_p(backupdir) FileUtils.chdir(backupdir) puts "Dumping database to activerecord yaml files in #{backupdir}" interesting_tables.each do |tbl| klass = tbl.classify.constantize puts "Writing #{tbl}..." File.open("#{tbl}.yml", 'w+') { |f| YAML.dump klass.find(:all).collect(&:attributes), f } end puts "Database Dumped.\n\n" end desc "Dump Current Environment Db to file" task :db => [:environment, :storedb ] do backupdir = RAILS_APPDIR + '/db/backup' archivedir = RAILS_APPDIR + '/db/backups' backup_filename = "#{RAILS_ENV}_db_backup_#{Time.now.strftime("%B.%d.%Y_at_%I.%M.%S%p_%Z")}.tar.bz2" FileUtils.mkdir_p(archivedir) puts "Archiving #{backupdir} yaml files to #{backup_filename}\n\n" `tar -C #{backupdir} -cjf #{backup_filename} *` `mv #{backup_filename} #{archivedir}` end desc "Restore Current Environment Db from a file" task :restoredb => [:environment] do backupdir = RAILS_APPDIR + '/db/backup' archivedir = RAILS_APPDIR + '/db/backups' print "Input a file to load into the db: #{archivedir}/" backup_filename = STDIN.gets.chomp puts "Loading backup file: #{backup_filename}" FileUtils.chdir(archivedir) `tar -xjf #{backup_filename}` `mv *.yml #{backupdir}` FileUtils.mkdir_p(backupdir) FileUtils.chdir(backupdir) interesting_tables.each do |tbl| puts "Clearing #{tbl} table.." ActiveRecord::Base.connection.execute "TRUNCATE #{tbl}" puts "Loading #{tbl} backup file..." table = YAML.load_file("#{tbl}.yml") if table.length > 0 && table.first.key?("id") highestid = 0 table.each do |fixture| if fixture["id"] > highestid highestid = fixture["id"] end end ActiveRecord::Base.connection.execute "SELECT setval('#{tbl}_id_seq',#{highestid})" puts "Setting #{tbl}_id sequence to #{highestid}" end #klass = tbl.classify.constantize ActiveRecord::Base.transaction do puts "Inserting #{table.length} values into #{tbl}" table.each do |fixture| ActiveRecord::Base.connection.execute "INSERT INTO #{tbl} (#{fixture.keys.join(",")}) VALUES (#{fixture.values.collect { |value| ActiveRecord::Base.connection.quote(value) }.join(",")})", 'Fixture Insert' end puts "#{tbl} table restored.\n\n" end end end end

// Greedy RegEx quantifier used // X+ = X, one or more times // [\\s,;]+ = one or more times of either \s , or ; String test_data = "hello world, this is a test, ;again"; _logger.debug("Source: " + test_data); for (String tag : test_data.split("[\\s,;]+")) { _logger.debug("Received tag: [" + tag + "]"); }

// XMLHttpRequest emulator using curl. * @version 0.5 2007/07/16 23:00:13 * @link http://www.myopera.com/moises-l Comments & suggestions * @link http://files.myopera.com/moises-l/files/class.XMLHttpRequest.php Available at * @copyright GPL © 2007, Moises Lima * @license http://creativecommons.org/licenses/by-nc-sa/2.5/ Released under a Creative Commons License */ class XMLHttpRequest{ /** * String version of data returned from server process. * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-responsetext * @access public * @var string * @name $responseText */ var $responseText; /** * DOM-compatible document object of data returned from server process. * which can be examined and parsed using W3C DOM node tree methods and properties * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-responsexml * @access public * @var object * @name $responseXML */ var $responseXML; /** * The http status code returned by server as a number (e.g. 404 for "Not Found" or 200 for "OK"). * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-status * @access public * @var number * @name $status */ var $status; /** * The http status code returned by server as a string (e.g. "Not Found" or "OK") * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-statustext * @access public * @var string * @name $statusText */ var $statusText; /** * The state of the object * 0 = uninitialized * 1 = loading * 2 = loaded * 3 = interactive * 4 = complete * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-readystate * @access public * @var number * @name $readyState */ var $readyState; /** * The error string * @link http://www.w3.org/TR/XMLHttpRequest/#notcovered * @access public * @var string * @name $error */ var $error; /** * An event handler for an event that fires at every state change * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-onreadystatechange * @access public * @name $onreadystatechange */ var $onreadystatechange; /** * An event handler for an event that fires at finished requisition * @link http://www.w3.org/TR/XMLHttpRequest/#notcovered * @access public * @name $onload */ var $onload; /** * An event handler for an event that fires at errors * @link http://www.w3.org/TR/XMLHttpRequest/#notcovered * @access public * @name $onerror */ var $onerror; // http://www.w3.org/TR/XMLHttpRequest/#notcovered /** * cURL handle * @access private * @name $curl */ var $curl; /** * responseHeaders process * @access private * @name $responseHeaders */ var $responseHeaders; /** * cURL headers * @access private * @name $headers */ var $headers=array("Connection: Keep-Alive","Keep-Alive: 300"); /** * Curl info * @access public * @name $curl_version * @var Array */ var $curl_version; /** * TRUE to follow any "Location: " header that the server sends as part of the HTTP header. * @access public * @name $followLocation * @var Bolean */ var $followLocation; /** * Class constructor (compatibility with PHP 4). */ function XMLHttpRequest(){ $this->open="function open() { [native code] }"; $this->setRequestHeader="function setRequestHeader() { [native code] }"; $this->getAllResponseHeaders="function getAllResponseHeaders() { [native code] }"; $this->getResponseHeader="function getResponseHeader() { [native code] }"; $this->send="function send() { [native code] }"; $this->readyState = 0; $this->curl = curl_init(); $this->curl_version = curl_version(); $this->followLocation=false; curl_setopt($this->curl, CURLOPT_HEADER, true); if(isset($_SERVER['HTTP_USER_AGENT'])){ curl_setopt($this->curl, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT'] ); }else{ curl_setopt($this->curl, CURLOPT_USERAGENT, "XMLHttpRequest/0.2"); } curl_setopt($this->curl, CURLOPT_RETURNTRANSFER, 1); curl_setopt($this->curl, CURLOPT_TIMEOUT, 1000); curl_setopt($this->curl, CURLOPT_CONNECTTIMEOUT, 300); } /** * @access private */ function __toString(){ return "[object XMLHttpRequest]"; } /** * Specifies the method, URL, and other optional attributes of a request. * @access public * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-open * @param String $method HTTP Methods defined in section 5.1.1 of RFC 2616 http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html * @param String $url Specifies either the absolute or a relative URL of the data on the Web service. * @param Bolean $async FakeSauro Erectus. * @param String $user specifies the name of the user for HTTP authentication. * @param String $password specifies the password of the user for HTTP authentication. * @return void */ function open($method, $url, $async=true, $user="", $password=""){ $this->readyState = 1; if(!empty($method) && !empty($url)){ $method=strtoupper(trim($method)); /* if(!ereg("^(GET|POST|HEAD|PUT|DELETE|OPTIONS)$",$method)){ throw new Exception("Unknown HTTP request method [$method]"); } */ if(isset($_SERVER['HTTP_REFERER']) && empty($this->url) ){ curl_setopt($this->curl, CURLOPT_REFERER, $_SERVER['HTTP_REFERER']); }elseif(isset($this->url)){ curl_setopt($this->curl, CURLOPT_REFERER, $this->url); } $this->url = $url; curl_setopt($this->curl, CURLOPT_URL, $this->url); if($method=="POST"){ curl_setopt($this->curl, CURLOPT_POST, 1); }elseif($method=="GET"){ curl_setopt($this->curl, CURLOPT_POST, 0); }else{ curl_setopt($this->curl, CURLOPT_POST, 0); curl_setopt($this->curl, CURLOPT_CUSTOMREQUEST, $method); } } if(ereg("^(https)",$url)){ curl_setopt($this->curl,CURLOPT_SSL_VERIFYPEER,false); } if(!empty($user) && !empty($password)){ curl_setopt($this->curl, CURLOPT_HTTPAUTH, CURLAUTH_ANY); curl_setopt($this->curl,CURLOPT_USERPWD,$user.":". $password); } } /** * Assigns a label/value pair to the header to be sent with a request. * @access public * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-setrequestheader * @param String $label Specifies the header label. * @param String $value Specifies the header value. * @return void */ function setRequestHeader($label, $value){ $this->headers[] = "$label: $value"; curl_setopt($this->curl, CURLOPT_HTTPHEADER, $this->headers); } /** * Returns complete set of headers (labels and values) as a string. * @access public * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-getallresponseheaders * @return string Complete set of headers (labels and values) as a string */ function getAllResponseHeaders(){ return $this->responseHeaders; } /** * Returns the value of the specified http header. * @access public * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-getresponseheader. * @param String $label * @return String|null The string value of a single header label. */ function getResponseHeader($label){ $value=array(); preg_match_all('/(?s)'.$label.': (.*?)\s\n/i', $this->responseHeaders , $value); if(count($value ) > 0){ return implode(', ' , $value[1]); } return null; } function getResponseHeader2($label){ $value=array(); preg_match('/(?s)'.$label.': (.*?)\s\n/i', $this->responseHeaders , $value); if(count($value ) > 0){ return $value[1]; } return null; } /** * Transmits the request, optionally with postable string or DOM object data. * @access public * @link http://www.w3.org/TR/XMLHttpRequest/#dfn-getresponseheader * @param String $data * @return void */ function send($data=null){ $sT=array(); if(isset($this->onreadystatechange))eval($this->onreadystatechange); if($data){ curl_setopt($this->curl, CURLOPT_POSTFIELDS, $data); } $this->response= curl_exec($this->curl); $header_size = curl_getinfo($this->curl, CURLINFO_HEADER_SIZE); $this->responseHeaders = substr($this->response, 0, $header_size - 4); if($this->followLocation){ $location=array(); while(preg_match('/Location:(.*?)\n/', $this->responseHeaders, $location)){ curl_setopt($this->curl, CURLOPT_REFERER, $this->url); $url = @parse_url(trim(array_pop($location))); if (!$url){ break; } $last_url = parse_url(curl_getinfo($this->curl, CURLINFO_EFFECTIVE_URL)); if (!isset($url['scheme']))$url['scheme'] = $last_url['scheme']; if (!isset($url['host']))$url['host'] = $last_url['host']; if (!isset($url['path']))$url['path'] = $last_url['path']; $this->url = $url['scheme'] . '://' . $url['host'] . $url['path'] . (isset($url['query'])?'?'.$url['query']:''); curl_setopt($this->curl, CURLOPT_POST, 0); //curl_setopt($this->curl, CURLOPT_POSTFIELDS,0); curl_setopt($this->curl, CURLOPT_URL, $this->url); $this->response= curl_exec($this->curl); $header_size = curl_getinfo($this->curl, CURLINFO_HEADER_SIZE); $this->responseHeaders = substr($this->response, 0, $header_size - 4); } } $this->error = curl_error($this->curl); if ($this->error) { if(isset($this->onerror))eval($this->onerror); } $this->readyState = 2; if(isset($this->onreadystatechange))eval($this->onreadystatechange); $this->responseText = substr($this->response, $header_size); preg_match('/^HTTP\/\d\.\d\s+(\d{3}) (.*)\s\n/i', $this->responseHeaders , $sT); if(count($sT ) > 2){ $this->responseHeaders = ereg_replace ($sT[0], "", $this->responseHeaders); $this->status = $sT[1]; $this->statusText = $sT[2]; } if(version_compare(PHP_VERSION , "5", ">=")){ if (preg_match('/(application|text)\/[\w+\+]?xml/i', $this->getResponseHeader("Content-Type"))){ libxml_use_internal_errors(true); $this->responseXML = new DOMDocument(); $this->responseXML->loadXML($this->responseText); $errors = libxml_get_errors(); if (!empty($errors)){ $this->responseXML=null; $error=$errors[0]; $this->error= trim($error->message) ." in $this->url on line $error->line column: $error->column "; if(isset($this->onerror))eval($this->onerror); } libxml_clear_errors(); } } $this->readyState = 3; if(isset($this->onreadystatechange))eval($this->onreadystatechange); $this->headers=Array(); $this->readyState = 4; if(isset($this->onreadystatechange))eval($this->onreadystatechange); if(isset($this->onload))eval($this->onload); } /** * Closes a cURL session and frees all resources. * @name close * @access public * @return void */ function close(){ curl_close($this->curl); } } ?>

You are changing the password for ". $info[$i]["givenname"][0] .", " . $info[$i]["sn"][0] ." (" . $info[$i]["samaccountname"][0] .") to " . $_POST['user_pass'] ." \n"; $passwd1 = $_POST['user_pass']; $userDn = $info[$i]["distinguishedname"][0]; $newPassword = $passwd1; $newPassword = "\"" . $newPassword . "\""; $len = strlen($newPassword); for ($i = 0; $i < $len; $i++){ $newPassw .= "{$newPassword{$i}\000";} $newPassword = $newPassw; $userdata["unicodePwd"] = $newPassword; $result = ldap_mod_replace($ldap, $userDn , $userdata); if ($result) echo "Your password has been changed!" ; else echo "There was a problem changing your password, please call IT for help"; } } @ldap_close($ldap); ?>

Remove nodes like (without attributes & without children) public static void RemoveEmptyNodes(XmlDocument doc) { XmlNodeList nodes = doc.SelectNodes("//node()"); foreach (XmlNode node in nodes) if ((node.Attributes.Count == 0) && (node.ChildNodes.Count == 0)) node.ParentNode.RemoveChild(node); }

// Adapted from http://javatechniques.com/blog/lucene-in-memory-text-search-example // Works with present APIs in Lucene 2.1.0 /** * A simple example of an in-memory search using Lucene. */ import java.io.IOException; import java.io.StringReader; import org.apache.lucene.search.Hits; import org.apache.lucene.search.Query; import org.apache.lucene.document.Field; import org.apache.lucene.search.Searcher; import org.apache.lucene.index.IndexWriter; import org.apache.lucene.document.Document; import org.apache.lucene.store.RAMDirectory; import org.apache.lucene.search.IndexSearcher; import org.apache.lucene.queryParser.QueryParser; import org.apache.lucene.queryParser.ParseException; import org.apache.lucene.analysis.standard.StandardAnalyzer; public class InMemoryExample { public static void main(String[] args) { // Construct a RAMDirectory to hold the in-memory representation // of the index. RAMDirectory idx = new RAMDirectory(); try { // Make an writer to create the index IndexWriter writer = new IndexWriter(idx, new StandardAnalyzer(), true); // Add some Document objects containing quotes writer.addDocument(createDocument("Theodore Roosevelt", "It behooves every man to remember that the work of the " + "critic, is of altogether secondary importance, and that, " + "in the end, progress is accomplished by the man who does " + "things.")); writer.addDocument(createDocument("Friedrich Hayek", "The case for individual freedom rests largely on the " + "recognition of the inevitable and universal ignorance " + "of all of us concerning a great many of the factors on " + "which the achievements of our ends and welfare depend.")); writer.addDocument(createDocument("Ayn Rand", "There is nothing to take a man’s freedom away from " + "him, save other men. To be free, a man must be free " + "of his brothers.")); writer.addDocument(createDocument("Mohandas Gandhi", "Freedom is not worth having if it does not connote " + "freedom to err.")); // Optimize and close the writer to finish building the index writer.optimize(); writer.close(); // Build an IndexSearcher using the in-memory index Searcher searcher = new IndexSearcher(idx); // Run some queries search(searcher, "freedom"); search(searcher, "free"); search(searcher, "progress or achievements"); searcher.close(); } catch (IOException ioe) { // In this example we aren’t really doing an I/O, so this // exception should never actually be thrown. ioe.printStackTrace(); } catch (ParseException pe) { pe.printStackTrace(); } } /** * Make a Document object with an un-indexed title field and an indexed * content field. */ private static Document createDocument(String title, String content) { Document doc = new Document(); // Add the title as an unindexed field… doc.add(new Field("title", title, Field.Store.YES, Field.Index.NO)); // …and the content as an indexed field. Note that indexed // Text fields are constructed using a Reader. Lucene can read // and index very large chunks of text, without storing the // entire content verbatim in the index. In this example we // can just wrap the content string in a StringReader. doc.add(new Field("content", new StringReader(content))); return doc; } /** * Searches for the given string in the "content" field */ private static void search(Searcher searcher, String queryString) throws ParseException, IOException { // Build a Query object QueryParser parser = new QueryParser("content", new StandardAnalyzer()); Query query = parser.parse(queryString); // Search for the query Hits hits = searcher.search(query); // Examine the Hits object to see if there were any matches int hitCount = hits.length(); if (hitCount == 0) { System.out.println("No matches were found for \"" + queryString + "\""); } else { System.out.println("Hits for \"" + queryString + "\" were found in quotes by:"); // Iterate over the Documents in the Hits object for (int i = 0; i < hitCount; i++) { Document doc = hits.doc(i); // Print the value that we stored in the "title" field. Note // that this Field was not indexed, but (unlike the // "contents" field) was stored verbatim and can be // retrieved. System.out.println(" " + (i + 1) + ". " + doc.get("title")); } } System.out.println(); } }

// description of your code here try { // // Create the XML Document // DocumentBuilderFactory dbfac = DocumentBuilderFactory.newInstance(); DocumentBuilder docBuilder = dbfac.newDocumentBuilder(); Document doc = docBuilder.parse(filePath); // ... } catch (Exception e) { // ... }

SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy"); Date date = sdf.parse(strDate); Calendar cal = Calendar.getInstance(); cal.setTime(date);

A range is a very handy feature of programing languages like Python. * range( 10 ) -> 0 1 2 3 4 5 6 7 8 9 * range( 5, 10 ) -> 5 6 7 8 9 * range( 0, 10, 3 ) -> 0 3 6 9 * range( '0', '9' ) -> 012345678 With an extended for loop it is possible to use such a feature too: /* * This project is made available under the terms of the BSD license, more information can be found at * http://www.opensource.org/licenses/bsd-license.html * * Copyright (c) 2007. Christian Ullenboom (http://www.tutego.com/) and contributors. All rights reserved. */ package com.tutego; import java.util.Iterator; /** * Class that generates immutable sequences (ranges) as Iterable * objects. A range represents a start (0 if not given), an stop (mandatory) and * an optional step (1 by default). The start value is included in the range, * the stop value is exclusive. Every range is handled by an Iterable * which can by used in an extended for loop. * * * for ( int i : range( 0, 10, 3 ) ) * System.out.print( i + " " ); // 0 3 6 9 * * * @author Christian Ullenboom (tutego) * @version 1.0 */ public class Range { public static Iterable range( final int start, final int stop, final int step ) { if ( step <= 0 ) throw new IllegalArgumentException( "step > 0 isrequired!" ); return new Iterable() { public Iterator iterator() { return new Iterator() { private int counter = start; public boolean hasNext() { return counter < stop; } public Integer next() { try { return counter; } finally { counter += step; } } public void remove() { } }; } }; } public static Iterable range( final int start, final int stop ) { return range( start, stop, 1 ); } public static Iterable range( final int stop ) { return range( 0, stop, 1 ); } } This is an example: package com.tutego; import static com.tutego.Range.range; public class RangeDemo { public static void main( String[] args ) { for ( int i : range( 10 ) ) System.out.print( i + " " ); System.out.println(); for ( int i : range( 5, 10 ) ) System.out.print( i + " " ); System.out.println(); for ( int i : range( 0, 10, 3 ) ) System.out.print( i + " " ); System.out.println(); for ( int i : range( '0', '9' ) ) System.out.print( (char) i ); System.out.println(); String[] a = { "Mary", "had", "a", "little", "lamb" }; for ( int i : range(a.length ) ) System.out.printf( "%d %s%n", i, a[i] ); } }

First a simple script for reading non-corruted zipfiles in python: filename = 'foo.zip' import zipfile z = zipfile.ZipFile(filename) for i in z.infolist(): print i.filename, i.file_size z.read('somefile') Next we use 'zip -FF foo.zip' to fix the zipfile, before reading it: filename = 'foo.zip' import zipfile try: z = zipfile.ZipFile(filename) except zipfile.BadZipfile: import commands commands.getoutput('zip -FF '+filename) z = zipfile.ZipFile(filename) for i in z.infolist(): print i.filename, i.file_size try: z.read('somefile') except zipfile.BadZipfile: print 'Bad CRC-32' In short: use 'zip -FF file.zip' to fix the file. It will restore the filelist.

1 import java.security.*; 2 import java.math.*; 3 4 public class MD5 { 5 public static void main(String args[]) throws Exception{ 6 String s="This is a test"; 7 MessageDigest m=MessageDigest.getInstance("MD5"); 8 m.update(s.getBytes(),0,s.length()); 9 System.out.println("MD5: "+new BigInteger(1,m.digest()).toString(16)); 10 } 11 }

// Programmatically Click the Form Submit Button // by using the 'click()' method submitTags : function() { var btnSubmitTags = document.getElementById( TagsHelperConfig.FORM_TAGS_ENTRY_SUBMIT_BUTTON_ID ); // Programmatically click the submit button btnSubmitTags.click(); }

import java.net.URL; import java.io.IOException; import java.net.URLClassLoader; import java.net.MalformedURLException; public class JarFileLoader extends URLClassLoader { public JarFileLoader (URL[] urls) { super (urls); } public void addFile (String path) throws MalformedURLException { String urlPath = "jar:file://" + path + "!/"; addURL (new URL (urlPath)); } public static void main (String args []) { try { System.out.println ("First attempt..."); Class.forName ("org.gjt.mm.mysql.Driver"); } catch (Exception ex) { System.out.println ("Failed."); } try { URL urls [] = {}; JarFileLoader cl = new JarFileLoader (urls); cl.addFile ("/opt/mysql-connector-java-5.0.4/mysql-connector-java-5.0.4-bin.jar"); System.out.println ("Second attempt..."); cl.loadClass ("org.gjt.mm.mysql.Driver"); System.out.println ("Success!"); } catch (Exception ex) { System.out.println ("Failed."); ex.printStackTrace (); } } }

Here's a really simple code snippet for retrieving parameters to a Java servlet.