Solution #1 (take 1) - Use a result object that map all possibile paths/...

[matteobaglini]

...use cases as methods, something like Boolean object in Smalltalk. Since Java 1.7 doesn't have block (aka lambda) like Smalltalk (and many other languages) I chose to use AnonimousClasses but they seem to have many scope issues with local variable. Next shot I'll try to use Java 1.8 with the brand new lambda support.

[matteobaglini]

This solution isn't obvious as the switch one, however, has two major advantages:

• The use of the "PermissionAction" indirection decouple the callee from caller and "AskResult" is unaware of the context where it's used so it's more reusable.
• The switch construct has the drawback that hard code the variation logic (aka procedural polimorfism), with the introduction of objects we open up to more powerful version of polimorfism and then objects composition in order to compose more complex high order logic without setting your hair on fire.