NullObject is not a GoF design pattern but a schema which appears frequently enough to be considered a pattern. It has the following benefits:
- Client code is simplified
- Reduces the chance of null pointer exceptions
- Fewer conditionals require less test cases
Methods that return an object or null should instead return an object or NullObject. NullObjects simplify boilerplate code such as if (!is_null($obj)) { $obj->callSomething(); } to just $obj->callSomething(); by eliminating the conditional check in client code.
- Symfony2: null logger of profiler
- Symfony2: null output in Symfony/Console
- null handler in a Chain of Responsibilities pattern
- null command in a Command pattern
You can also find this code on GitHub
Service.php
Service.php
LoggerInterface.php
LoggerInterface.php
PrintLogger.php
PrintLogger.php
NullLogger.php
NullLogger.php
Tests/LoggerTest.php
Tests/LoggerTest.php