Updated abstract method signature information and added an example to clarify on optional arguments.

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@327966 c90b9560-bf6c-de11-be94-00142212c4b1
This commit is contained in:
Sherif Ramadan 2012-10-09 13:24:53 +00:00
parent bc8b580e62
commit ac5ed968ff

View file

@ -19,8 +19,10 @@
if the abstract method is defined as protected, the function implementation
must be defined as either protected or public, but not private. Furthermore
the signatures of the methods must match, i.e. the type hints and the number
of required arguments must be the same. This also applies to constructors as
of PHP 5.4. Before 5.4 constructor signatures could differ.
of required arguments must be the same. For example, if the child class
defines an optional argument, where the abstract method's signature does
not, there is no conflict in the signature. This also applies to constructors
as of PHP 5.4. Before 5.4 constructor signatures could differ.
</para>
<example>
@ -83,6 +85,49 @@ FOO_ConcreteClass2
</screen>
</example>
<example>
<title>Abstract class example</title>
<programlisting role="php">
<![CDATA[
<?php
abstract class AbstractClass
{
// Our abstract method only needs to define the required arguments
abstract protected function prefixName($name);
}
class ConcreteClass extends AbstractClass
{
// Our child class may define optional arguments not in the parent's signature
public function prefixName($name, $separator = ".") {
if ($name == "Pacman") {
$prefix = "Mr";
} elseif ($name == "Pacwoman") {
$prefix = "Mrs";
} else {
$prefix = "";
}
return "{$prefix}{$separator} {$name}";
}
}
$class = new ConcreteClass;
echo $class->prefixName("Pacman"), "\n";
echo $class->prefixName("Pacwoman"), "\n";
?>
]]>
</programlisting>
&example.outputs;
<screen>
<![CDATA[
Mr. Pacman
Mrs. Pacwoman
]]>
</screen>
</example>
<para>
Old code that has no user-defined classes or functions named
'abstract' should run without modifications.