21 lines
844 B
Markdown
21 lines
844 B
Markdown
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---
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layout: pattern
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title: Dependency Injection
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folder: dependency-injection
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categories: pattern_cat
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tags: pattern_tag
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---
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**Intent:** Dependency Injection is a software design pattern in which one or
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more dependencies (or services) are injected, or passed by reference, into a
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dependent object (or client) and are made part of the client's state. The
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pattern separates the creation of a client's dependencies from its own
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behavior, which allows program designs to be loosely coupled and to follow the
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inversion of control and single responsibility principles.
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**Applicability:** Use the Dependency Injection pattern when
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* when you need to remove knowledge of concrete implementation from object
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* to enable unit testing of classes in isolation using mock objects or stubs
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