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[Andromdaplugins-cvs] CVS update: cartridges/andromda-ejb3/src/site/xdoc howto11.xml
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From: Vance K. <va...@us...> - 2006-03-03 15:25:52
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User: vancek
Date: 06/03/03 07:25:51
Added: andromda-ejb3/src/site/xdoc howto11.xml
Log:
initial revision
Revision Changes Path
1.1 cartridges/andromda-ejb3/src/site/xdoc/howto11.xml
Index: howto11.xml
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<?xml version="1.0" encoding="iso-8859-1"?>
<document>
<properties>
<author email="va...@us...">Vance Karimi</author>
<title>AndroMDA - EJB3 - Environment Entry Injection</title>
</properties>
<body>
<section name="Injection">
<p>
The EJB 3.0 spec allows different types of injections such as <i>dependency injection
and simple environment entry injections.</i> We will discuss how the EJB3 cartridge
handles these injections differently.
</p>
<a name="Dependency_Injection"/>
<subsection name="Dependency Injection">
<p>
To inject dependencies using the EJB3 cartridge, simply model a dependency from the
source class to the injected target class where each class has a suitable stereotype
associated with it.
</p>
<p>
You can inject a session bean instance into a session or a message-driven bean by drawing
a dependency from the source session bean to the target session or message-driven bean.
The source bean will include the <code>@EJB</code> annotation on the declared field. Upon
creation of the source bean instance, the EJB container will set the instance of the injected
destination bean using the JNDI name of the referenced EJB.
</p>
<p>
The injected session bean instance name is simply the name of the target session bean with
lower case first character.
</p>
<p>
The EJB 3.0 spec allows resource injections using the <code>@Resource</code> annotation and
the EJB3 cartridge uses this feature in a few ways.
</p>
<p>
Firstly, all session beans automatically inject the <code>SessionContext</code> using
the <code>@Resource</code> annotation into the instance <code>context</code> using a
<code>protected</code> visibility. You can then use this <code>SessionContext</code>
in the session bean implementation.
</p>
<p>
If a session bean is marked for bean managed transaction demarcation by modelling the
<code>@andromda.ejb.transaction.management</code> tagged value set to <code>BEAN</code>,
then the EJB3 cartridge will automatically inject an instance of <code>UserTransaction</code>
into the variable <code>userTrans</code> using a <code>protected</code> visibility. You can
then use this <code>UserTransaction</code> instance in the session bean implementation.
</p>
<p>
The EJB3 cartridge will also use the <code>@Resource</code> annotation to setup an instance of
the appropriate <code>ConnectionFactory</code> and <code>Destination</code> objects for
seding message to JMS queues where you have servicing message-driven beans. By modelling
a dependency from the source session bean to the target message-driven bean, be it a MDB
servicing a <code>Topic</code> or <code>Queue</code>, all the necessary injections are
generated. You can find an example in the <a href="howto10.html">message-driven</a>
howto.
</p>
</subsection>
<a name="Simple_Environment_Entry_Injection"/>
<subsection name="Simple Environment Entry Injection">
<p>
Setting up an environment entry configuration parameter is very simple using the EJB3
cartridge. The environment entry value may have one of the following Java types:
<ul>
<li>String</li>
<li>Character</li>
<li>Integer</li>
<li>Boolean</li>
<li>Double</li>
<li>Byte</li>
<li>Short</li>
<li>Long</li>
<li>Float</li>
</ul>
</p>
<p>
To inject an environment entry resource value, model a service or message-driven bean attribute
with <i>classifer</i> scope and set the attribute stereotype to <![CDATA[<<EnvEntry>>]]>.
The environment entries will be defined in the session or message-driven bean class and
configured in the ejb-jar.xml deployment descriptor.
You must define a default value for these attributes in the model.
</p>
<p>
The following example illustrates how you can inject environment entries into session beans.
</p>
<p>
<img src="images/org/andromda/test/11/a/uml.gif"/>
</p>
<p>
<ul>
<li class="gen">Auto-generated source that does not need manual editing</li>
<li class="impl">Auto-generated source that should be edited manually</li>
<li class="changed">File that is affected by the modifications applied in this section</li>
</ul>
</p>
<p>
<ul>
<li class="gen"><a href="src/org/andromda/test/howto11/a/CarEmbeddable.java.txt"><code>CarEmbeddable.java</code></a></li>
<li class="impl"><a href="src/org/andromda/test/howto11/a/Car.java.txt"><code>Car.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto11/a/CarType.java.txt"><code>CarType.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto11/a/PersonEmbeddable.java.txt"><code>PersonEmbeddable.java</code></a></li>
<li class="impl"><a href="src/org/andromda/test/howto11/a/Person.java.txt"><code>Person.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/ServiceLocator.java.txt"><code>ServiceLocator.java</code></a></li>
<li class="gen"><a class="changed" href="src/org/andromda/test/howto11/a/RentalServiceBean.java.txt"><code>RentalServiceBean.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto11/a/RentalServiceRemote.java.txt"><code>RentalServiceRemote.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto11/a/RentalServiceDelegate.java.txt"><code>RentalServiceDelegate.java</code></a></li>
<li class="impl"><a href="src/org/andromda/test/howto11/a/RentalServiceBeanImpl.java.txt"><code>RentalServiceBeanImpl.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto11/a/RentalServiceException.java.txt"><code>RentalServiceException.java</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto11/a/RentalException.java.txt"><code>RentalException.java</code></a></li>
<li class="gen"><a class="changed" href="src/org/andromda/test/howto11/a/ejb-jar.xml.txt"><code>ejb-jar.xml</code></a></li>
<li class="gen"><a href="src/org/andromda/test/howto11/a/jboss.xml.txt"><code>jboss.xml</code></a></li>
</ul>
</p>
<p>
The two important files to look at are <code>RentalServiceBean.java</code> and
<code>ejb-jar.xml</code>. The <code>RentalServiceBean.java</code> injects the resource using
the <code>@Resource</code> annotation and specifies the name property corresponding to the
<code>env-entry-name</code> in <code>ejb-jar.xml</code> for the environment entry.
</p>
</subsection>
</section>
<section name="Next">
<p>
To find out how service delegates work, click <a href="howto12.html">here</a>.
</p>
</section>
</body>
</document>
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