GRASP (object-oriented design): Difference between revisions

Revision as of 18:02, 21 December 2007

Revision as of 18:03, 21 December 2007

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===Creator===

The '''Creator''' pattern solves the problem of who should be responsbile for the creation of a new instance of a class. The creator pattern is important because creation of objects is one of the most ubiquitous activites in an object-oriented system. A system that effectivly utilizes the creator pattern can also support low coupling, increased understandability, encapsulation and the liklihood that the object in question will be capable of sustaining reuse. Given two classes, class B and Class A, class B should be responsibile for the creation of A if class B contains or compositely aggregates, records, closley uses or contains the initlaizing information for class A. It could then be stated that B is a creator of A objects.<ref>(Larman 292)</ref>

The '''Creator''' pattern deals with assigning the responsibility of creating new objects (instances of classes). New instances of class ''Class'' should be created by a class such that:

* it aggregates instances of ''Class'', or;

* it contains instances of ''Class'', or;

* it records instances of ''Class'', or;

* it closely uses instances of ''Class'', or;

* it has the necessary information for creating the new instance of ''Class''.

===Controller===