Improve the Context API

[jknack]

Problem:

If a user want to extends the context-stack, it have to use the "wrap" method of ContextFactory

Root Context:

  Context context = ContextFactory.wrap(model);

Child Context:

  Context context = ContextFactory.wrap(model);
  Context child = ContextFactory.wrap(context, moreData);

This works but have two disadvantages:

1. The semantic isn't enough "wrap" isn't a clear name
2. The object attributes are bind to the "root", this is error-prone and the context will get lost.

Solution

The new API has more semantic and help to reduce errors

Root Context:

  Context root = Context.newContext(model);

Child Context:

  Context root = Context.newContext(model);
  Context child = Context.newContext(child, data);

Extended Context:

  Context root = Context.newContext(model)
     .combine("user", user)
     .combine(map)
     .build();