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23 lines
806 B
Markdown
23 lines
806 B
Markdown
# Null Object
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## Purpose
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NullObject is not a GoF design pattern but a schema which appears frequently enough to be considered a pattern. It has the following benefits:
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* Client code is simplified
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* Reduces the chance of null pointer exceptions
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* Fewer conditionals require less test cases
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Methods that return an object or null should instead return an object or `NullObject`. `NullObject`s simplify boilerplate code such as `if (!is_null($obj)) { $obj->callSomething(); }` to just `$obj->callSomething();` by eliminating the conditional check in client code.
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## Examples
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* Symfony2: null logger of profiler
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* Symfony2: null output in Symfony/Console
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* null handler in a Chain of Responsibilities pattern
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* null command in a Command pattern
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## UML Diagram
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