Why use shared libraries ?

todo

Since the petals-bc-ejb is a generic binding component that allows to call Enterprise Java Beans running on different kind of application servers, you must add your application specific RMI client libraries to the component classpath. There are three solutions to add the libraries to do so :

• add the libraries directly in the component classpath (bad)
• add the libraries to each deployed service unit (average)
• add the libraries to a shared library deployed before component startup (good)

By default this component uses a shared library called "petals-sl-ejb" which must contains the RMI client libraries of the EJB targeted EJB container with its JEE EJB specification.

Anatomy of a shared library

Content of a shared library

A shared library archive may look like this :

my-shared-library.zip
   + META-INF
     - jbi.xml
   - my-shared-library.jar
   - my-jar-dependency1.jar
   - my-jar-dependency2.jar
   - my-jar-dependency3.jar

Adding jar files to the archive is not sufficient. Each jar contained by the shared library must be declared within its JBI descriptor.

JBI descriptor of a shared library

Here is an exemple of such files (jbi.xml file) :

<?xml version="1.0" encoding="UTF-8"?>
<jbi:jbi
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:petals="http://petals.ow2.org/extensions"
    xmlns:jbi="http://java.sun.com/xml/ns/jbi" version="1.0">

  <jbi:shared-library class-loader-delegation="self-first" version="my-shared-library-versionXYZ">

    <jbi:identification>
      <jbi:name>petals-sl-ejb</jbi:name>
      <jbi:description>My Shared Library vXYZ</jbi:description>
    </jbi:identification>

    <jbi:shared-library-class-path>
      <jbi:path-element>my-shared-library.jar</jbi:path-element>
      <jbi:path-element>my-jar-dependency1.jar</jbi:path-element>
      <jbi:path-element>my-jar-dependency2.jar</jbi:path-element>
      <jbi:path-element>my-jar-dependency3.jar</jbi:path-element>
    </jbi:shared-library-class-path>

  </jbi:shared-library>
</jbi:jbi>

Using a shared library

Finally, to add this shared library to the component classpath you must add the following section to the JBI descriptor of the component just after the end of the "bootstrap-class-path" element :

<shared-library>my-shared-library</shared-library>

Info todo