Middlegen provides an Ant task from which to initiate the code generation for the target platforms. The task can include more than a single target, eg, Hibernate and EJB target. The following task is configured for the Hibernate plugin only.

<!-- ============================================================== -->
<!-- Run Middlegen -->
<!-- ============================================================== -->

<target
   name="middlegen"
   description="Run Middlegen"
   unless="middlegen.skip"
   depends="init,fail-if-no-xdoclet-1.2,check-driver-present,panic-if-driver-not-present"
>
  <mkdir dir="${build.gen-src.dir}"/>
  <echo message="Class path = ${basedir}"/>

  <taskdef
    name="middlegen"
    classname="middlegen.MiddlegenTask"
    classpathref="lib.class.path"
  />

  <middlegen
    appname="${name}"
    prefsdir="${src.dir}"
    gui="${gui}"
    databaseurl="${database.url}"
    initialContextFactory="${java.naming.factory.initial}"
    providerURL="${java.naming.provider.url}"
    datasourceJNDIName="${datasource.jndi.name}"
    driver="${database.driver}"
    username="${database.userid}"
    password="${database.password}"
    schema="${database.schema}"
    catalog="${database.catalog}"
  >

     <!-- Plugins -->
     <hibernate
        destination="${build.gen-src.dir}"
        package="${name}.hibernate"
        javaTypeMapper="middlegen.plugins.hibernate.HibernateJavaTypeMapper"
     />

   </middlegen>
   <mkdir dir="${build.classes.dir}"/>
</target>

The majority of the task options involves setting up the data source. Fine-tuning of the generation process is provide primarily through a Java Swing based GUI. This is activated when the gui option in the Middlegen Ant task is true. Middlegen has a sample application that can provide a guide for your own project adoption of Middlegen.

Middlgen by default creates Hibernate 2.x mapping files. Middlgen 2.2 introduced the option of creating Hibernate 3.0 mapping files by using the version element. For example;

  ....

     <!-- Plugins -->
     <hibernate
        destination="${build.gen-src.dir}"
        package="${name}.hibernate"
        javaTypeMapper="middlegen.plugins.hibernate.HibernateJavaTypeMapper"
        version="3.0"
     />

  ...

Note: hibernate tools package has vastly improved and is worth considering as an alternative for hibernate 3.x features.