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.
例子 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()
?>
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例子 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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