Comparing Spring and Camel Examples

One of the blogs I follow is from Gunnar Hillert, whom back in 2009 discovered Camel and wrote a nice blog entry. He also did some investigation of Camel alternatives as well. One of the alternatives is Spring Integration. Gunnar since joined VMWare to be part of the Spring team.

This morning I read Gunnar's new post about creating a Spring Integration project in STS tooling here. The STS creates a simple out of the box example, that provides the following XML (in screenshot) as the main logic. Take a moment to see if you can figure out what it does. And then compare to the equivalent Camel example below.

Spring Integration - Simple Example created by STS tooling

 
And here is the Camel example using XML as well:

Apache Camel - The same example as above

Having both screenshots, I guess you can figure out that the example:

1. reads input from the console
2. upper case the input
3. and prints it back on the console

This example will be provided out of the box in the upcoming Apache Camel 2.10, in the examples/camel-example-console directory. You can see the source code here.

You can run it from command line using Maven
mvn compile exec:java

And then press ctrl + c to stop the application.

Running the Camel example from command line

Or you can run it from within your IDE of choice, such as IDEA / Eclipse / FuseIDE by running the CamelConsoleMain class. For example as the screenshot shows below from IDEA.

Running the example from your editor such as IDEA

To create a new Camel project you can use the Camel Maven archetypes. Or use Fuse IDE which has a wizard just like STS to create a new Camel project.

A few notes about Camel. The example uses Spring and XML, however Camel can be used without Spring at all. We could use pure Java and define the Camel route in a Java class. You can also use Scala. And for XML we could also have used OSGi Blueprint.

In the example we use the built-in Simple language to upper case the input. You can chose to use more powerful dynamic languages such as Groovy, OGNL, Mvel, JavaScript etc as well.

With Camel you simply have more choices, and don't have to use XML at all.