content/application-discovery-via-the-classpath.mdtext

Title: Application discovery via the classpath
This document details the various ways to get OpenEJB to detect
applications you would like deployed while in an embedded mode.

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# Empty ejb-jar.xml approach (recommended)

Simplify the issue of searching for annotated applications by adding an
ejb-jar.xml like this to your app:

    <ejb-jar/>


OpenEJB will find the app in the classpath and deploy it along with any
annotated beans it may contain.

The ejb-jar.xml can contain more than just "<ejb-jar/>" as usual.

This is the recommended approach for people using OpenEJB for unit testing
as it allows OpenEJB to find your application in the classpath without the
need for you to specify any path information which tends to complicate
builds.
    
# Including/Excluding paths (advanced)
    
If you do not like the idea of having the ejb-jar.xml in your app or an
openejb.xml, we can search the classpath for annotated beans (@Stateless,
@Stateful, @MessageDriven) and load them automatically just as if they
contained an ejb-jar.xml.

This form of searching, however, is very expensive as it involves iterating
over every path in the classpath and reading in each class definition
contained thereunder and checking it for annotations.

This approach can only be made faster by helping us trim down or pinpoint
the paths we should search via the *openejb.deployments.classpath.include*
property which can be specified as a _system property_ or a property passed
into the _InitialContext_.  

The value of this property is a regular expression and therefore can be
absolute or relative.  For example the path
"/Users/dblevins/work/swizzle/swizzle-stream/target/classes" which contains
the class files of an application you wish to test could be included in any
of the following values to the "openejb.deployments.classpath.include"
property:
    
* "file:///Users/dblevins/work/swizzle/swizzle-stream/target/classes/" _(an absolute path)_
* "file:///Users/dblevins/work/swizzle/.*" _(relative)_
* ".\*swizzle-stream.\*" _(very relative)_
* ".\*(swizzle-stream|swizzle-jira|acme-rocket-app).\*" _(including several paths)_
* ".\*(swizzle-stream^|swizzle-jira^|acme-rocket-app).\*" _(including several paths with Win specific escapes)_
    
Note the filtering is done on URLs in the classpath, so forward slashes
should always be used even on OSs using backslash ("\").
    
There are also the *openejb.deployments.classpath.exclude* and *openejb.exclude-include.order*
properties if you wish to work in the opposite direction or change the processing order.
The default values for the properties are as follows:
    
      openejb.exclude-include.order=include-exclude //Defines the processing order
	   openejb.deployments.classpath.include=""      //Include nothing
       openejb.deployments.classpath.exclude=".*"    //Exclude everything
    
The exclude and the include are applied separately and the results of each
are combined together to create the list of paths OpenEJB will scrape for
annotations.
    
    *Note:* by default these settings will only affect which jars OpenEJB will
	 scan for annotated components when no descriptor is found.  If you would
	 like to use these settings to also filter out jars that do contain
	 descriptors, set the *openejb.deployments.classpath.filter.descriptors*
	 property to _true_.  The default is _false_.
    
# Troubleshooting

If the include/exclude is not being processed as you expect first try
reversing the order to *openejb.exclude-include.order*=exclude-include
There are a number internal filters that may result in an unexpected exclusion.
    
If you're having trouble determining if the META-INF/ejb-jar.xml file for
your ejb module is in the classpath, a little debug code like this in your
test setup will help you see what OpenEJB sees (which may be nothing):
    

    Enumeration<URL> ejbJars =
    this.getClass().getClassLoader().getResources("META-INF/ejb-jar.xml");
    while (ejbJars.hasMoreElements()) {
        URL url = ejbJars.nextElement();
        System.out.println("app = " + url);
    }