GlassFish Migration: WebLogic's Split Directory To Ear

As I wrote in the blog on Verification Tools for Migration to GlassFish, GlassFish verifier tool is handy for verifiying the Java EE compliance of an application. Verifier is run as follows

                verifier --portablity archive

at seems simple enough to run, but it does require an archive (ear/war/jar/rar). The source application server (e.g. WebLogic ) from which the application is being migrated to GlassFish will usually provide a mechnism to generate an archive file. Here, I will examine the generation of an ear file on WebLogic 9.2 when split directory development is being used. A lot of the samples in WebLogic 9.2 distribution use the split directory development model. And I ran into a problem while trying to generate an archive file for the JSP Simple Tag sample that I had migrated earlier. I will describe both the problem and the workaround.

Background on Split Directory Development

The split directory development model is targeted towards iterative development. The essence of this type of development is that there are two directories:

• src directory : This directory contains sources, including deployment descriptors.
• build directory : This directory contains compiled classes.

WebLogic provides an Ant task - wlpackage - to package the src and build directory contents into a single EAR file or an archive directory in an exploded format. For e.g.

       
        <!-- package to an ear file -->
        <wlpackage srcdir="${src.dir}" destdir="${dest.dir}
                   toFile="${ear.file}" />

        <!-- package to an exploded directory -->
        <wlpackage srcdir="${src.dir}" destdir="${dest.dir}
                   toDir="${ear.exploded.dir}" />

Every WebLogic 9.2 server sample's build.xml contained an Ant target "package.exploded.ear" that packaged the src and build directory into an ear in exploded format. But there was no ant target for packaging into a J2EE ear. Note: The WebLogic 9.2 BuildXMLGen facility does generate a build.xml with an Ant target for building both ear file as well as a standard J2EE expoloded directory. I am not sure why the build.xml files in the samples do not have such a target.

So I thought I would use wlpackage to package an ear file. The problem I ran into is that the ear file generated was not Java EE compliant. The files for the web module were packaged in an exploded format rather than being packaged into a war file first, and then packaging the war file into the ear file. Thus, the web-uri XML element in the application.xml points to an exploded directory rather than a war file, causing the verifier to fail with an exception.

        <!-- Archive contents produced by wlpackage -->
        <!-- Note: jspSimpleTagWar is a directory not a war file -->
             META-INF/
             META-INF/MANIFEST.MF
             META-INF/application.xml
             jspSimpleTagWar/
             jspSimpleTagWar/ExamplesFooter.jsp 
             ...

        <!-- META-INF/application.xml -->
        <?xml version="1.0" encoding="UTF-8"?>
        <application xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.4">
          <description>JSP 1.2 Simple Tag API Example</description>
          <display-name>JSP 1.2 Simple Tag API Example</display-name>
            <module>
              <web>
                <web-uri>jspSimpleTagWar</web-uri>
                <context-root>jsp_simpleTag</context-root>
              </web>
            </module>
        </application>

I worked around the above problem as described below.

• Build the ear in exploded format on WebLogic 9.2. Every server sample in WebLogic 9.2 distribution has a build.xml file an ant target "package.exploded.ear", which will build package the contents of src and build directory into an EAR file in exploded directory format.

        <target name="package.exploded.ear">
            <wlpackage srcdir="${dist}" destdir="${examples.build.dir}/${bean.ear}"
                       toDir="${dist}" />
        </target>
  

• Make a copy of application.xml to gf-application.xml and change from directory to a jar file name. This will replace the application.xml.

          <!-- META-INF/application.xml -->
          <?xml version="1.0" encoding="UTF-8"?>
          <application xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.4">
            <description>JSP 1.2 Simple Tag API Example</description>
            <display-name>JSP 1.2 Simple Tag API Example</display-name>
              <module>
                <web>
                  <web-uri>jspSimpleTag.war</web-uri>
                  <context-root>jsp_simpleTag</context-root>
                </web>
              </module>
          </application>
  

• Run the WebLogic supplied ant target to create an ear in exploded directory format. In the JSP Simple Tag example, you can do this by:

             cd <weblogic92>/samples/server/examples/src/examples/webapp/jsp/tags/simple/
             ant package.exploded.ear
  

  This creates <weblogic92>/samples/server/examples/src/examples/webapp/jsp/tags/simple/jspSimpleTagEar exploded directory

• Run the following target with will take the exploded directory and package the ear file correctly. (For simplicity, I hardcoded values for directories).

        <target name="all">
           <!-- package the J2EE exploded ear into an archive -->
          <mkdir dir="archivedir"/>
          <jar destfile="archivedir/jspSimpleTag.war" basedir="jspSimpleTagEar/jspSimpleTagWar"/>
          <copy todir="archivedir/META-INF">
              <fileset dir="jspSimpleTagEar/META-INF"
                       excludes="**/application.xml"/>
          </copy>
          <copy file="gf-application.xml" tofile="archivedir/META-INF/application.xml"/>
          <jar destfile="jspSimpleTag.ear" basedir="archivedir"/>
          </target>
  

The generated ear will look like this.

        Ear file format
        META-INF/
        META-INF/MANIFEST.MF
        META-INF/application.xml
        META-INF/weblogic-application.xml
        jspSimpleTag.war

Summary

WebLogic supports a split directory development. WebLogic provides ant task for packaging an ear file. But the ear generated cannot be processed by the ear file. I have showed one way to get around this problem using an ant script that packages the contents of an exploded archive directory into an ear file for consumption by verifier.

It would be useful if the verifier tool itself could be used on an exploded directory. But that is another topic for another day.