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Creating a Hello World

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JBI

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This tutorial describes how to create a very simple Hello World style of JBI service engine (SE) component. It demonstrates some best practices for creating JBI components. The example in this tutorial is as minimalistic as possible so as to focus on key concepts and not drown in details. The example component will respond to all requests with the message:

Prerequisites

• Maven 2.0.4 or higher
  • If you have never used Maven previously the Maven Getting Started Guide explains some valuable concepts surrounding Maven
• ServiceMix 3.1 or higher
  • See the ServiceMix downloads
• A broadband internet connection (so Maven can automatically download dependencies)

A Very Brief Introduction to Java Business Integration

The Java Business Integration (JBI) spec provides a standards-based, service-oriented approach to application integration through the use of an abstract messaging model, without reference to a particular protocol or wire encoding. JBI introduces the concepts of Binding Components (BCs), Service Engines (SEs) to Service Units (SUs) and Service Assemblies (SAs) to define an architecture for vendor-neutral pluggable components. The purpose of this architecture is to provide standards-based interoperability amongst components/services.

JBI components are can be thought of as the smallest applications or services accessible in a service-oriented architecture. Each service has a very specific purpose and therefore a narrow scope and set of functionality. Components come in two flavours: Service Engine (SE) and Binding Components (BC). Several SUs are packed into a SA. An SA is a complete application consisting of one or more services interacting with one another.

See also the page providing information on working with service units

Below are some quick definitions:

• Component Architecture
  • Binding Components - Components that provide or consume services via some sort of communications protocol or other remoting technology
  • Service Engines - Components that supply or consume services locally (within the JBI container)

• Component Packaging
  • Service Units - Packaging for an individual service that allows deployment to the JBI container; similar to a WAR file from J2EE
  • Service Assemblies - Packaging for groups of SUs for deployment to the JBI container; similar to an EAR file from J2EE

For further reading, see the JBIforSOI document for a good introduction to JBI.

Creating the Maven Projects for Each Component

Service Engine

This tutorial describes how to create a very simple Hello World style of JBI service engine (SE) component. It demonstrates some best practices for creating JBI components. The example in this tutorial is as minimalistic as possible so as to focus on key concepts and not drown in details. The example component will respond to all requests with the message:

Prerequisites

• Maven 2.0.4 or higher
  • If you have never used Maven previously the Maven Getting Started Guide explains some valuable concepts surrounding Maven
• ServiceMix 3.1 or higher
  • See the ServiceMix downloads
• A broadband internet connection (so Maven can automatically download dependencies)

A Very Brief Introduction to Java Business Integration

The Java Business Integration (JBI) spec provides a standards-based, service-oriented approach to application integration through the use of an abstract messaging model, without reference to a particular protocol or wire encoding. JBI introduces the concepts of Binding Components (BCs), Service Engines (SEs) to Service Units (SUs) and Service Assemblies (SAs) to define an architecture for vendor-neutral pluggable components. The purpose of this architecture is to provide standards-based interoperability amongst components/services.

JBI components are can be thought of as the smallest applications or services accessible in a service-oriented architecture. Each service has a very specific purpose and therefore a narrow scope and set of functionality. Components come in two flavours: Service Engine (SE) and Binding Components (BC). Several SUs are packed into a SA. An SA is a complete application consisting of one or more services interacting with one another.

See also the page providing information on working with service units

Below are some quick definitions:

• Component Architecture
  • Binding Components - Components that provide or consume services via some sort of communications protocol or other remoting technology
  • Service Engines - Components that supply or consume services locally (within the JBI container)

• Component Packaging
  • Service Units - Packaging for an individual service that allows deployment to the JBI container; similar to a WAR file from J2EE
  • Service Assemblies - Packaging for groups of SUs for deployment to the JBI container; similar to an EAR file from J2EE

For further information on JBI, see the JBI section of the User's Guide. See also the JBIforSOI document for a decent introduction to JBI.

Creating the Maven Projects for Each Component

Creating a Maven Subproject For the JBI Service Engine

The focus of this section is on the creation of a JBI component. For this task, a Maven archetype will be used to create a Maven project skeleton to house the component. Maven archetypes are templates for Maven projects that jumpstart project creation via the automation of repetitive tasks by following standard conventions. The result of using an archetype to create a Maven project is a directory structure, a Maven POM file and, depending on the archetype being used, sometimes Java objects and JUnit tests.

1) Create a directory named hello-world-smx and switch to that directory:

$ mkdir hello-world-smx
$ cd hello-world-smx

2) Use the servicemix-service-engine Maven archetype to generate a Maven project for the SE:

The command above will create a directory named hello-world-se that houses a Maven project for the JBI service engine being created here. The name of the directory is taken from the artifactId parameter.

The first three parameters to the mvn command (-DarchetypeGroupId=org.apache.servicemix.tooling -DarchetypeArtifactId=servicemix-service-engine -DarchetypeVersion=3.1-incubating-SNAPSHOT) identify which Maven archetype to use for the archetype:create goal, while the last two parameters (-DgroupId=org.apache.servicemix.samples.helloworld -DartifactId=hello-world-se) uniquely identify the Maven project that is being generated. The groupId (printed in pink) is used as the Java package and the artifactId is used as the project name. Therefore, only alphanumeric characters are valid values for the groupId and artifactId parameters.

The output from executing the archetype:create goal is shown below (only relevant information has been preserved):

\[INFO\] Scanning for projects...
\[INFO\] Searching repository for plugin with prefix: 'archetype'.
\[INFO\] \---------------------------------------------------------------------------\-
\[INFO\] Building Maven Default Project
\[INFO\]    task-segment: \[archetype:create\] (aggregator-style)
\[INFO

Creating a Maven Subproject For the JBI Service Engine

The focus of this section is on the creation of a JBI component. For this task, a Maven archetype will be used to create a Maven project skeleton to house the component. Maven archetypes are templates for Maven projects that jumpstart project creation via the automation of repetitive tasks by following standard conventions. The result of using an archetype to create a Maven project is a directory structure, a Maven POM file and, depending on the archetype being used, sometimes Java objects and JUnit tests.

1) Create a directory named hello-world-smx and switch to that directory:

$ mkdir hello-world-smx
$ cd hello-world-smx

2) Use the servicemix-service-engine Maven archetype to generate a Maven project for the SE:

The command above will create a directory named hello-world-se that houses a Maven project for the JBI service engine being created here. The name of the directory is taken from the artifactId parameter.

The first three parameters to the mvn command (-DarchetypeGroupId=org.apache.servicemix.tooling -DarchetypeArtifactId=servicemix-service-engine -DarchetypeVersion=3.1-incubating-SNAPSHOT) identify which Maven archetype to use for the archetype:create goal, while the last two parameters (-DgroupId=org.apache.servicemix.samples.helloworld -DartifactId=hello-world-se) uniquely identify the Maven project that is being generated. The groupId (printed in pink) is used as the Java package and the artifactId is used as the project name. Therefore, only alphanumeric characters are valid values for the groupId and artifactId parameters.

The output from executing the archetype:create goal is shown below (only relevant information has been preserved):

\[INFO\] Scanning for projects...
\[INFO\] Searching repository for plugin with prefix: 'archetype'.
\[INFO\] \---------------------------------------------------------------------------\-
...
\[INFO\] Building Maven Default Project
\[INFO\]    task-segment: \[archetype:create\] (aggregator-style)
\[INFO\] \---------------------------------------------------------------------------\-
...
\[INFO\] <span style="color: #ff00ff">Defaulting package to group ID: org.apache.servicemix.samples.helloWorldSE</span>
...
\[INFO\] **\**\**\**\**\**\**\**\**\**\* End of debug <span style="color: #ff00ff">Defaulting package to group ID: org.apache.servicemix.samples.helloWorldSE</span>
...
\[INFO\] **\**\**\**\**\**\**\**\**\**\* End of debug info from resources from generated POM **\**\******************\*
\[INFO\] <span style="color: #009900">Archetype created in dir: /Users/bsnyder/src/hello-world-se/hello-world-se</span>
\[INFO\] \-----------------------------------------------------------------------\-
\[INFO\] BUILD SUCCESSFUL
\[INFO\] \-----------------------------------------------------------------------\-

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[INFO] Scanning for projects...
[INFO] ----------------------------------------------------------------------------
[INFO] Building A custom project
[INFO]    task-segment: [test]
[INFO] ----------------------------------------------------------------------------
...
[INFO] [compiler:compile]
...
[INFO] [surefire:test]
[INFO] Setting reports dir: c:\java\tmp\servicemix-helloWorldSE\target/surefire-reports
-------------------------------------------------------
 T E S T S
-------------------------------------------------------
[surefire] Running org.apache.servicemix.samples.helloWorldSE.MySpringComponentTest
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[surefire] Tests run: 1, Failures: 0, Errors: 0, Time elapsed: 1,422 sec
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ---------------------------------------------------------------------------
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Generation and Deployment of the SA

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Generation and Deployment of the SA

The execution of the install goal above packages not only each component individually, it also packages the components together into a single SA. Of course, the code does not yet do anything, but we can already deploy the SA ServiceMix by switching to the hello-world-se/hello-world-sa directory and executing the jbi:projectDeploy goal like so:

$ mvn jbi:projectDeploy

This tells the Maven JBI plugin to deploy the components to ServiceMix. When the deployment is complete, ServiceMix will output the following:

INFO  - ServiceAssemblyLifeCycle       - Starting service assembly: hello-world-sa

This output tells us that the SA was successfully deployed to ServiceMix.

<build>
<plugins>
  <plugin>
    <artifactId>jbi-maven-plugin</artifactId>
    <configuration>
      <deployDependencies>false</deployDependencies>
    </configuration>
  </plugin>
</plugins>
</build>

Adding Functionality to the Component

We're now ready to add a bit of functionality to the component. Using an IDE like IntelliJ IDEA or Eclipse make this task much easier. The steps described here apply to Eclipse.

...

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$ mvn 

eclipse:

eclipse

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INFO  - ServiceAssemblyLifeCycle       - Starting service assembly: hello-world-sa

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<build>
<plugins>
  <plugin>
    <artifactId>jbi-maven-plugin</artifactId>
    <configuration>
      <deployDependencies>false</deployDependencies>
    </configuration>
  </plugin>
</plugins>
</build>

Adding Functionality to the Component

We're now ready to add a bit of functionality to the component. Using an IDE like IntelliJ IDEA or Eclipse make this task much easier. The steps described here apply to Eclipse.

$ mvn eclipse:eclipse

Additional Resources

• Creating a Standard JBI Component
• Notes on Creating JBI Component using maven2
• Roadmap for a perspective Servicemix developer