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Context:
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Creating objects by two criteria: Base type (Known to the application) and
environment (preconfigured). (E.g. creating GUI controls, given control type and
knowing the GUI system being emulated).
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An array of factory methods with the same implementation criterion. (Same
example as above, where the need for each control type has aroused on a
separate occasion.)
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Challenge:
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To encapsulate the decisions in a single object.
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Skill:
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Participants:
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Abstract Factory:
| A Singleton. The capability to create discrete products for a pre-configured
environment.
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Concrete Factory:
| A set of methods for creating discrete products for a concrete environment.
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(Some) Abstract Product:
| (A passive entity.) One of the Abstract Factory's declared Product types.
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(Some) Concrete Product:
| (A passive entity.) The implementation of one of the Abstract Factory's declared
Product types for a particular environment.
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Signature:
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Abstract factory responds to creation messages
explicitly named after each conceptual product type. Each
concrete factory implements this interface for a concrete environment. The
products are arranged in respective discrete type families where environment
implementations derive from product.
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Used patterns and idioms:
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singleton.
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Source:
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GOF.
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Scope:
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General.
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