You use the application programming interface of Rational® Programming Patterns for System z® to access the Pacbase entities in Java™.
You create your own micropatterns in dedicated Eclipse plug-ins and then write their contents directly in Java.
To write this Java code, you will probably have to access the model instances. With the application programming interface named 'Model Access Facilities', you can access the instances of your local workspace and retrieve their properties. For a Data Element, you can retrieve its formats, usage, parent Data Element...
You can also use the application programming interface of Rational Programming Patterns for System z to create your own batch command lines and user menus.