Behavioral Pattern

Gamma et al have also described a number of behavioral patterns:

• Chain of responsability (a request goes through an ordered chain of potential Workers, the appropriate worker determines that he has to treat the request, in that way the requester does not need to know any thing about the receiver of the request)
• Command (a request is wrapped in to an object in order to allow the parametrisation, the queueing, logging or cancellation of the request)
• Interpreter ()
• Iterator (a mean of accessing sequentially the elements of a aggregate object without revealing its internal structure)
• Mediator (an object which encapsulate the way different object interact with each others)
• Memento (method to capture and externalise the structure of an object to restore it later)
• Observer (an object offers the possibility of registering a number of observers which are notified as soon as some state is reached)
• State (the behavior of an object is dependant on the internal state of the object )
• Strategy ( define a number of interchangeable algorithms which can be used for a variety of clients and situations)
• Template Method ( defines a super class which provides a skeleton of the different steps which have to be performed in an algorithm, the subclasses of this superclass implement specifically these parts)
• Visitor (define operation which have to be performed on some objects of a structure and store the code for this operation in a separate object)