In java, can one create a fluent extensible class hierarchy with methods that can be invoked in any order?

Question

Can one create an extensible class hierarchy in java whose methods are fluent and can be invoked in any order? (YES! see answer below), even for existing classes wh

Answer 1

A fluent interface is a different concern from the normal set of command-query methods that you already have. Separation of concerns makes it a good idea to separate them.

Since you have an existing hierarchy of code: Write a fluent facade that does the dirty work for you.

See also Martin Fowler: Domain-Specific Languages, 4.2: The need for a Parsing Layer.