Pattern Specializes

A more specific pattern specializes a more general pattern if the specific pattern's full description is a direct extension of the more general pattern.

That is, the specific pattern must deal with a specialisation of the problem the general pattern addresses, must have a similar (but more specialised) solution structure, and must address the same forces as the more general pattern, but may also address additional forces. To make an analogy with object-oriented programming, the PatternUses relationship is similar to composition, while the PatternSpecializes relationship is similar to inheritance.

In the GOFBook FactoryMethod specializes TemplateMethod, because Factory Methods are effectively Hook Methods which are used by subclasses to specify the class of an object the Template Method in the superclass will create.

The Specializes relationship can be used to identify abstract patterns by generalisation --- similar to the way inheritance can be used to identify abstract classes. For example, in the DesignPatternsSmalltalkCompanion, PatternSpecializes is used to introduce various Smalltalk versions of patterns. So ChainOfResponsibility specializes OoRecursion?, PluggableAdaptor specialises Adaptor, Bridge specializes CollaboratingHierarchies?, Flyweight specialises Sharable.

JamesNoble

RelationshipsBetweenPatterns