56 lines
2.2 KiB
Markdown
56 lines
2.2 KiB
Markdown
---
|
|
layout: pattern
|
|
title: Abstract Factory
|
|
folder: abstract-factory
|
|
permalink: /patterns/abstract-factory/
|
|
pumlid: PSZB3OD034NHLa81Czwd6sCC39gVxEUWT1_ssLmTtQLqgR5fM7sTmFGtaV6TZu8prd0r6HtQaMKqAZLk1XjT_E6qgPUZfyc0MdTgx0-8LuUn8ErFXdr98NypXxKyezKV
|
|
categories: Creational
|
|
tags:
|
|
- Java
|
|
- Gang Of Four
|
|
- Difficulty-Intermediate
|
|
---
|
|
|
|
## Also known as
|
|
Kit
|
|
|
|
## Intent
|
|
Provide an interface for creating families of related or dependent
|
|
objects without specifying their concrete classes.
|
|
|
|
|
|
|
|
## 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
|
|
|
|
* [javax.xml.parsers.DocumentBuilderFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/parsers/DocumentBuilderFactory.html)
|
|
* [javax.xml.transform.TransformerFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/transform/TransformerFactory.html#newInstance--)
|
|
* [javax.xml.xpath.XPathFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/xpath/XPathFactory.html#newInstance--)
|
|
|
|
## Credits
|
|
|
|
* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
|