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h1. Features

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This Binding Component (BC) allows to interact with external Enterprise Java Beans (EJB) running on an external JEE container. This Binding Component (BC) allows Petals ESB to interact with external Enterprise Java Beans (EJB) running on an external JEE container.

This component has been successfully tested with the following EJB specifications :

* 2.0
* 2.1
* 3.0
* 3.1

On the following JEE container :

* JOnAS
* JBoss
* OC4J
* OpenEJB

This component acts only as a service provider. A JBI message exchange sent to a ServiceEndpoint (mapped to an EJB) is transformed into an EJB call through RMI.
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h1. Component Configuration

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Before installing the bc-ejb component, you must check in your $\{PETALS_HOME}/conf/server.properties configuration file if the property "petals.classloaders.isolated=true" is set and uncommented. The BC-EJB component need the isolated classloaders to work correctly.

The component can be configured through its JBI descriptor file like this :
{code:lang=xml}<?xml version="1.0" encoding="UTF-8"?>
<jbi:jbi xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:petalsCDK="http://petals.ow2.org/components/extensions/version-4.0"
xmlns:jbi="http://java.sun.com/xml/ns/jbi" version="1.0">

<jbi:component type="binding-component" component-class-loader-delegation="parent-first">

<jbi:identification>
<jbi:name>petals-bc-ejb</jbi:name>
<jbi:description>an EJB Binding Component sending messages to local or distant EJB instances</jbi:description>
</jbi:identification>

<jbi:component-class-name>org.ow2.petals.bc.ejb.EjbBC</jbi:component-class-name>
<jbi:component-class-path>
<jbi:path-element/>
</jbi:component-class-path>
<jbi:bootstrap-class-name>org.ow2.petals.component.framework.DefaultBootstrap</jbi:bootstrap-classname>
<jbi:bootstrap-class-path>
<jbi:path-element/>
</jbi:bootstrap-class-path>

<petalsCDK:acceptor-pool-size>5</petalsCDK:acceptor-pool-size>
<petalsCDK:processor-pool-size>10</petalsCDK:processor-pool-size>
<petalsCDK:ignored-status>NOTHING_IGNORED</petalsCDK:ignored-status>
<shared-library>petals-sl-ejb</shared-library>
<petalsCDK:jbi-listener-class-name>org.ow2.petals.bc.ejb.listener.JBIListener</petalsCDK:jbi-listener-class-name>
</jbi:component>
</jbi:jbi>{code}


This component doesn't have any specific configuration parameters.&nbsp;

You can customize the component configuration by changing the following common parameters.
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{warning}EJB binding component can only handle outgoing message (JBI \-> EJB), so you can't specify an external-listenerclass-name.{warning}
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h1. Service Configuration


h2. Send a JBI message to an external EJB

When a JBI message is received on an endpoint linked to an EJB, the message is transformed into a RMI message, then&nbsp;sent to the linked EJB.

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!petals-bc-ejb.png!

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The RMI message is created following these steps :
# The JBI message payload is mapped to Java objects. These objects (and their types) are used as operation parameters&nbsp;for the RMI call. The mapping is done thanks to the PEtALS-JAXB-Databinding library. For more information about&nbsp;XML databinding feel free to read the chapter entitled XML to Java binding.
# The JBI message exchange operation local part is used as the EJB method to invoke.
# If a security subject is provided by the JBI message it is used as authentication information during the RMI invokation.

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For more information about JAAS read the chapter : JAAS authentication for EJB calls
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In order to reach the remote EJB, the component need to get an RMI stub of the EJB from a JNDI server. The JNDI name of the target EJB is defined in the parameter ejb.jndi.name.

The external EJB is called and the response is processed by the PEtALS-JAXB-Databinding library and then returned&nbsp;to the JBI environment.

h2. Service Unit descriptor

The Service Unit descriptor file ( jbi.xml ) looks like this :
{code:lang=xml}<?xml version="1.0" encoding="UTF-8"?>

<!--
JBI descriptor for the PEtALS' "petals-bc-ejb" component (EJB).
Originally created for the version 1.1 of the component.
-->

<jbi:jbi version="1.0"
xmlns:ejb="http://petals.ow2.org/components/ejb/version-1.1"
xmlns:generatedNs="http://application.localisation.watersupply.petals.ow2.org/"
xmlns:jbi="http://java.sun.com/xml/ns/jbi"
xmlns:petalsCDK="http://petals.ow2.org/components/extensions/version-4.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

<!-- Import a Service into PEtALS or Expose a PEtALS Service => use a BC. -->
<jbi:services binding-component="true">

<!-- Import a Service into PEtALS => provides a Service. -->
<jbi:provides
interface-name="generatedNs:LocalisationFinderBusinessServicePortType"
service-name="generatedNs:LocalisationFinderBusinessService"
endpoint-name="LocalisationFinderBusinessServiceEndpoint">

<!-- CDK specific elements -->
<petalsCDK:wsdl>Localisation.wsdl</petalsCDK:wsdl>

<!-- Component specific elements -->
<ejb:ejb.jndi.name>LocalisationFinderBusinessService</ejb:ejb.jndi.name>
<ejb:java.naming.factory.initial>org.jnp.interfaces.NamingContextFactory</ejb:java.naming.factory.initial>
<ejb:java.naming.provider.url>jnp://localhost:1099/</ejb:java.naming.provider.url>
<ejb:ejb.version>2.1</ejb:ejb.version>
<ejb:ejb.home.interface>org.ow2.petals.watersupply.localisation.application.LocalisationFinderBusinessServiceRemoteHome</ejb:ejb.home.interface>
<ejb:marshalling.engine>jaxb</ejb:marshalling.engine>
<ejb:security.name />
<ejb:security.principal />
<ejb:security.credencials />

</jbi:provides>
</jbi:services>