root/branches/PRE_NAMESPACES/examples/MathExtension.php

<?php
/**
 * Basic example to show how extensions may return values.
 * 
 * @author  Stephan Schmidt <stephan.schmidt@schlund.de>
 * @author  Frank Kleine <frank.kleine@schlund.de>
 */
/**
 * Basic example to show how extensions may return values.
 * 
 * @package     XJConf
 * @subpackage  examples
 */
class MathExtension implements Extension
{
    /**
     * the namespace
     *
     * @var  string
     */
    private $namespace = 'http://www.schst.net/XJConf/Math';
    
    /**
     * Get the namespace URI used by the extension
     * 
     * @return  string
     */
    public function getNamespace()
    {
        return $this->namespace;
    }
    
    /**
     * Process a start element
     * 
     * @param  XmlParser  $parser
     * @param  Tag        $tag
     * @throws XJConfException
     */
    public function startElement(XmlParser $parser, Tag $tag)
    {
        // nothing to do here
    }
    
    /**
     * Process the end element
     * 
     * @param   XmlParser  $parser
     * @param   Tag        $tag
     * @throws  XJConfException
     */
    public function endElement(XmlParser $parser, Tag $tag)
    {
        // add several values
        if ($tag->getName() == 'add') {
            $result = 0;
            
            $children = $tag->getChildren();
            foreach ($children as $child) {
                $result = $result + $child->getConvertedValue(); 
            }
            
            $resultTag = new GenericTag($tag->getName());
            $resultTag->setValue((double)$result);            
            return $resultTag;
        }
        
        return null;
    }
}
?>