WeberDev.com -> PHP Manual -> Register extended class used to create base node type

Description

bool DOMDocument::registerNodeClass ( string $baseclass , string $extendedclass )

This method allows you to register your own extended DOM class to be used afterward by the PHP DOM extension.

This method is not part of the DOM standard.

Parameters

baseclass

The DOM class that you want to extend. You can find a list of these classes in the chapter introduction.

Of course, you won't be able to register a class extending DOMDocument but you can always start your document by instanciating your own extending class.

extendedclass

Your extended class name. If NULL is provided, any previously registered class extending baseclass will be removed.

Return Values

Returns TRUE on success or FALSE on failure.

ChangeLog

Version	Description
PHP 5.2.2	Prior to 5.2.2, a previously registered `extendedclass` had to be unregistered before being able to register a new class extending the same `baseclass` .

Examples

Example #1 Adding a new method to DOMElement to ease our code

 <?php

class myElement extends DOMElement {
   function appendElement($name) { 
      return $this->appendChild(new myElement($name));
   }
}

class myDocument extends DOMDocument {
   function setRoot($name) { 
      return $this->appendChild(new myElement($name));
   }
}

$doc = new myDocument();
$doc->registerNodeClass('DOMElement', 'myElement');

// From now on, adding an element to another costs only one method call ! 
$root = $doc->setRoot('root');
$child = $root->appendElement('child');
$child->setAttribute('foo', 'bar');

echo $doc->saveXML();

?>

The above example will output:

  <?xml version="1.0"?> <root><child foo="bar"/></root>

Example #2 Retrieving elements as custom class

 <?php
class myElement extends DOMElement {
    public function __toString() {
        return $this->nodeValue;
    }
}

$doc = new DOMDocument;
$doc->loadXML("<root><element><child>text in child</child></element></root>");
$doc->registerNodeClass("DOMElement", "myElement");

$element = $doc->getElementsByTagName("child")->item(0);
var_dump(get_class($element));

// And take advantage of the __toString method..
echo $element;
?>

The above example will output:

  string(9) "myElement" text in child