OGNL (Object-Graph Navigation Language is an open-source expression language for getting and setting properties of Java objects.
It is famously used as an expression language in environments like the Apache Click, Spring Web Flow, WebWork and Tapestry web frameworks.
An example getter method navigation equivalent to getUser().getCompany().getName():
Which would be easy to use in op4j:
String name = Op.on(session).exec(FnOgnl.s("user.company.name")).get();
But OGNL can do much more than just navigating getters, like:
See more examples at the Language Guide in the OGNL project page: http://www.opensymphony.com/ognl/
The extension comprises only one function hub class: