PHP 手冊
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# Final Keyword

PHP 5 introduces the final keyword, which prevents child classes from overriding a method by prefixing the definition with final. If the class itself is being defined final then it cannot be extended.

範例 19-27. Final methods example

`<?php class BaseClass { public function test() { echo "BaseClass::test() called\n"; } final public function moreTesting() { echo "BaseClass::moreTesting() called\n"; } } class ChildClass extends BaseClass { public function moreTesting() { echo "ChildClass::moreTesting() called\n"; } } // Results in Fatal error: Cannot override final method BaseClass::moreTesting() ?>`

範例 19-28. Final class example

`<?php final class BaseClass { public function test() { echo "BaseClass::test() called\n"; } // Here it doesn't matter if you specify the function as final or not final public function moreTesting() { echo "BaseClass::moreTesting() called\n"; } } class ChildClass extends BaseClass { } // Results in Fatal error: Class ChildClass may not inherit from final class (BaseClass) ?>`

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