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.
Example #1 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()
?> Example #2 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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