9.4. Packaging AOP Applications

To deploy an AOP application in JBoss Enterprise Web Platform you need to package it. AOP is packaged similarly to SARs (MBeans). You can either deploy an XML file directly in the deploy/ directory with the signature *-aop.xml along with your package (this is how the base-aop.xml, included in the jboss-aop.deployer file works) or you can include it in the JAR file containing your classes. If you include your XML file in your JAR, it must have the file extension .aop and a jboss-aop.xml file must be contained in a META-INF directory, for instance: META-INF/jboss-aop.xml.
In the JBoss Enterprise Web Platform 5, you must specify the schema used, otherwise your information will not be parsed correctly. You do this by adding the xmlns="urn:jboss:aop-beans:1:0 attribute to the root aop element, as shown here:
<aop xmlns="urn:jboss:aop-beans:1.0">
</aop>
If you want to create anything more than a non-trivial example, using the .aop JAR files, you can make any top-level deployment contain an AOP file containing the XML binding configuration. For instance you can have an AOP file in an EAR file, or an AOP file in a WAR file. The bindings specified in the META-INF/jboss-aop.xml file contained in the AOP file will affect all the classes in the whole WAR file.
To pick up an AOP file in an EAR file, it must be listed in the .ear/META-INF/application.xml as a Java module, as follows:
<?xml version='1.0'  encoding='UTF-8'?>
<!DOCTYPE application PUBLIC '-//Sun Microsystems, Inc.//DTD J2EE Application 1.2//EN''http://java.sun.com/j2ee/dtds/application_1_2.dtd'>
 
<application>
	<display-name>AOP in JBoss example</display-name>
	<module>
		<java>example.aop</java>
	</module>
	<module>
		<ejb>aopexampleejb.jar</ejb>
	</module>
	<module>
		<web>
			<web-uri>aopexample.war</web-uri>
			<context-root>/aopexample</context-root>
		</web>
	</module>
</application>

Important

In the JBoss Enterprise Web Platform 5, the contents of the .ear file are deployed in the order they are listed in the application.xml. When using loadtime weaving the bindings listed in the example.aop file must be deployed before the classes being advised are deployed, so that the bindings exist in the system before (for example) the ejb and servlet classes are loaded. This is acheived by listing the AOP file at the start of the application.xml. Other types of archives are deployed before anything else and so do not require special consideration, such as .sar and .war files.