php-doc-en/language/oop5/final.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
 <sect1 xml:id="language.oop5.final" xmlns="http://docbook.org/ns/docbook">
  <title>Final Keyword</title>
  <para>
   PHP 5 introduces the final keyword, which prevents child classes from
   overriding a method by prefixing the definition with <emphasis>final</emphasis>. If the class
   itself is being defined final then it cannot be extended.
  </para>
  <para>
   <example>
    <title>Final methods example</title>
    <programlisting role="php">
<![CDATA[
<?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()
?> 
]]>
   </programlisting>
  </example>
  </para>
  <para>
   <example>
    <title>Final class example</title>
    <programlisting role="php">
<![CDATA[
<?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)
?> 
]]>
    </programlisting>
   </example>
  </para>
  <note>
   <simpara>
    Properties and constants cannot be declared final, only classes and methods 
    may be declared as final.
   </simpara>
  </note>
 </sect1>
 
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->