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Abstract Factory

Difficulty-Intermediate Gang Of Four Java Creational

Also known as

Kit

Intent

Provide an interface for creating families of related or dependent objects without specifying their concrete classes.

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Applicability

Use the Abstract Factory pattern when

  • a system should be independent of how its products are created, composed and represented
  • a system should be configured with one of multiple families of products
  • a family of related product objects is designed to be used together, and you need to enforce this constraint
  • you want to provide a class library of products, and you want to reveal just their interfaces, not their implementations
  • the lifetime of the dependency is conceptually shorter than the lifetime of the consumer.
  • you need a run-time value to construct a particular dependency
  • you want to decide which product to call from a family at runtime.
  • you need to supply one or more parameters only known at run-time before you can resolve a dependency.

Use Cases:

  • Selecting to call the appropriate implementation of FileSystemAcmeService or DatabaseAcmeService or NetworkAcmeService at runtime.
  • Unit test case writing becomes much easier

Consequences:

  • Dependency injection in java hides the service class dependencies that can lead to runtime errors that would have been caught at compile time.

Real world examples

Credits