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First some background. A JBI component is either a service engine (SE) or a binding component (BC). These terms are defined in Introduction to ESB and/or the Glossary. A BC/SE is installed on ServiceMix by copying it into the install directory which resides under the ServiceMix home directory. So what gets deployed? JBI components can act as containers themselves. Artifacts can be deployed to an existing BC or SE to add more functionality to that component. Adding artifacts to installed components is called deployment. To deploy artifacts to a component the artifacts can be placed in the deploy directory under the ServiceMix home directory. Another A term that is important to know is service assembly. A service assembly is a collection of deployment artifacts and metadata. A service unit is a single deployment artifact which is deployed on a single component. For deployment to happen, the artifacts must be in a very specific format, which is specified in the JSR 208 specification. Please see chapter 6 of the JSR 208 specification for more details. In addition to deploying components, ServiceMix allows servicemix. xml files to be deployed in a similar method to deploying a component.

Manually Creating a Service Unit and Service Assembly

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There are several things to note about this example. First of all it is meant to be run stand-alone. Specifically, when running this example, ServiceMix will be started for you, then the loan broker is deployed and run. Therefore, there is a servicemix.xml file in the loan-broker directory. This servicemix.xml file is used for configuring the ServiceMix JBI container upon ServiceMix starting up. This is not to be confused with the servicemix.xml located in the loan-broker\src\su directory. The SU servicemix.xml file is used to configure the servicemix-lwcontainer. Every service unit must contain some kind of configuration file. For example, if we were creating a service unit for the BPEL service engine there would also be a configuration file, but it would not be a servicemix.xml file, such as the one used for configuring the lightweight container.

NOTE: There are two major phases to creating a lightweight component that is ready for deployment: one, is the development phase of the component, which includes coding and compiling and building the code, the second phase is creating the packaging necessary for the component to be installed onto the JBI container. This document will focus on the second part. Any steps relating to compilation are simply performed here to get us to the point that we can assemble the component into a JBI service assembly or service unit.

In general, there are three steps to creating the SA and deploying it to the ServiceMix container.

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The following provides details on each general step above using an the loan-broker example to illustrate.

Although we are not covering the component development phase, in this case we do need to perform a compile. We will use Apache Ant to compile the loan-broker demo components:

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1. First create the service unit. The service unit is a ZIP file that will contain your application's Java class files and the servicemix.xml configuration file. For example:
   

   1. Wiki Markup
      Use a ZIP compression tool, such as Winzip or gzip to create a zip file containing the classes in \[servicemix_dir\]\examples\loan-broker\build\loanbroker\components and the {{servicemix.xml}} file which can be found in {{\[servicemix_dir\]\src\su}}. The zip file name is arbitrary, but it is used in the Service Assembly's {{jbi.xml}} file, so to match the example call it {{loanbroker-su.zip}}. \\

   2. Wiki Markup
      Put the {{loanbroker-su.zip}} file in the {{\[servicemix_dir\]\examples\loan-broker\build}} directory for later use. Note: you may store the zip file anywhere. \\ \\ The above two steps can be done automatically using the ant script: "ant build-su". If you look in the {{build.xml}} file you will see the {{build-su}} target does exactly what we just did manually. \\

2. Create the Service Assembly. A service assembly is a zip file containing one or more service units and a jbi.xml file. The jbi.xml file must be in the META-INF directory. you may also include other files in the META-INF directory. The ZIP file directory structure for our example looks like this:

   Code Block
   loanbroker-su.zip META-INF\ jbi.xml LICENSE.txt DISCLAIMER.txt

   
   
   The jbi.xml looks like this:

   Code Block

   <?xml version="1.0" encoding="UTF-8"?> <jbi xmlns="http://java.sun.com/xml/ns/jbi" version="1.0"> <service-assembly> <identification> <name>loanbroker</name> <description>LoanBroker Service Assembly</description> </identification> <service-unit> <identification> <name>loanbroker</name> <description>LoanBroker Service Unit</description> </identification> <target> <artifacts-zip>loanbroker-su.zip</artifacts-zip> <component-name>servicemix-lwcontainer</component-name> </target> </service-unit> </service-assembly> </jbi>

   
   
   The interesting thing to note is that the jbi.xml file tells the JBI container what service units are in the service assembly and where to deploy them. There is only one service unit in our example, which is "loanbroker" and the component to which it will be deployed is servicemix-lwcontainer (see the <component-name> tag). There could be multiple service units in a service assembly and they would each be included in the jbi.xml file with the same type of information for each.
   Create the service assembly ZIP file and include the loanbroker-su.zip file and the META-INF\jbi.xml directory and file in it. To remain consistent with our example, call the zip file loanbroker-sa.zip.

   1. Wiki Markup
      Put the {{loanbroker-sa.zip}} file in the {{\[servicemix_dir\]\examples\loan-broker\build}} directory for later use. Note: you may store the zip file anywhere.

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