Design Patterns in Java™, Second Edition

25 Interpreter

AS WITH THE COMMAND pattern, the INTERPRETER pattern produces an executable object. The patterns differ in that INTERPRETER involves the creation of a class hierarchy in which each class implements, or interprets, a common operation in a way that matches the class’s name. In this regard, INTERPRETER is similar to the STATE and STRATEGY patterns. In INTERPRETER, STATE, and STRATEGY, a common operation appears throughout a collection of classes, with each class implementing the operation in a different way.

The INTERPRETER pattern is also similar to the COMPOSITE pattern, which defines a common interface for individual items and groups of items. COMPOSITE does not require different, interesting ways of forming groups, although ...