DOMDocument::registerNodeClass

    (PHP 5 >= 5.2.0, PHP 7, PHP 8)

    DOMDocument::registerNodeClass — Register extended class used to create base node type

    Beschreibung

    publicDOMDocument::registerNodeClass(string$baseClass, ?string$extendedClass): bool

    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.

    Achtung

    The constructor of the objects of the registered node classes is not called.

    Parameter-Liste

    baseClass

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

    extendedClass

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

    Rückgabewerte

    Gibt bei Erfolg true zurück. Bei einem Fehler wird false zurückgegeben.

    Beispiele

    Beispiel #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();

    ?>

    Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

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

    Beispiel #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;
    ?>

    Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

    string(9) "myElement" text in child

    Beispiel #3 Retrieving owner document

    When instantiating a custom DOMDocument the ownerDocument property will refer to the instantiated class. However, if all references to that class are removed, it will be destroyed and new DOMDocument will be created instead. For that reason you might use DOMDocument::registerNodeClass() with DOMDocument

    <?php
    class MyDOMDocument extends DOMDocument {
    }

    class     MyOtherDOMDocument extends DOMDocument {
    }

    // Create MyDOMDocument with some XML
    $doc = new MyDOMDocument;
    $doc->loadXML("<root><element><child>text in child</child></element></root>");

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

    // The current owner of the node is MyDOMDocument
    var_dump(get_class($child->ownerDocument));
    // MyDOMDocument is destroyed
    unset($doc);
    // And new DOMDocument instance is created
    var_dump(get_class($child->ownerDocument));

    // Import a node from MyDOMDocument
    $newdoc = new MyOtherDOMDocument;
    $child = $newdoc->importNode($child);

    // Register custom DOMDocument
    $newdoc->registerNodeClass("DOMDocument", "MyOtherDOMDocument");

    var_dump(get_class($child->ownerDocument));
    unset(    $doc);
    // New MyOtherDOMDocument is created
    var_dump(get_class($child->ownerDocument));
    ?>

    Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

    string(13) "MyDOMDocument" string(11) "DOMDocument" string(18) "MyOtherDOMDocument" string(18) "MyOtherDOMDocument"

    Beispiel #4 Custom objects are transient

    Achtung

    Objects of the registered node classes are transient, i.e. they are destroyed when they are no longer referenced from PHP code, and recreated when being retrieved again. That implies that custom property values will be lost after recreation.

    <?php
    class MyDOMElement extends DOMElement
    {
    public     $myProp = 'default value';
    }

    $doc = new DOMDocument();
    $doc->registerNodeClass('DOMElement', 'MyDOMElement');

    $node = $doc->createElement('a');
    $node->myProp = 'modified value';
    $doc->appendChild($node);

    echo     $doc->childNodes[0]->myProp, PHP_EOL;
    unset(    $node);
    echo     $doc->childNodes[0]->myProp, PHP_EOL;
    ?>

    Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

    modified value default value
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