Subversion-Projekte lars-tiefland.php_share

<?php

/**

 * This file contains the class XML_Query2XML_Data_Source_XPath.

 *

 * PHP version 5

 *

 * @category  XML

 * @package   XML_Query2XML

 * @author    Lukas Feiler <lukas.feiler@lukasfeiler.com>

 * @copyright 2009 Lukas Feiler

 * @license   http://www.gnu.org/copyleft/lesser.html  LGPL Version 2.1

 * @version   CVS: $Id: XPath.php 276639 2009-03-01 13:17:08Z lukasfeiler $

 * @link      http://pear.php.net/package/XML_Query2XML

 * @access    private

 */

/**

 * XML_Query2XML_Data_Source_ColumnValue extends the class

 * XML_Query2XML_Data_Source.

 */

require_once 'XML/Query2XML/Data/Source.php';

/**

 * Data Source Class that allows the results of an XPath query to be used

 * as a data source.

 *

 * usage:

 * <code>

 * $commandObject = new XML_Query2XML_Data_Source_XPath(

 *   new DOMXPath(DOMDocument::load('albums.xml')),

 *   '/music_store/album[artist_id="?"]',

 *   array('artistid')

 * );

 * </code>

 *

 * @category  XML

 * @package   XML_Query2XML

 * @author    Lukas Feiler <lukas.feiler@lukasfeiler.com>

 * @copyright 2009 Lukas Feiler

 * @license   http://www.gnu.org/copyleft/lesser.html  LGPL Version 2.1

 * @version   Release: @package_version@

 * @link      http://pear.php.net/package/XML_Query2XML

 * @access    private

 * @since     Release 1.8.0RC1

 */

class XML_Query2XML_Data_Source_XPath extends XML_Query2XML_Data_Source

{

    /**

     * THe DOMXPath instance used.

     * @var DOMXPath An instance of DOMXPath

     */

    private $_xpath = null;

    /**

     * An array of column names.

     * @var array

     */

    private $_data = array();

    /**

     * The placeholder string to be used.

     * @var string

     */

    private $_placeholder;

    /**

     * Constructor function.

     *

     * @param DOMXPath $xpath       An instance of DOMXPath.

     * @param string   $query       The XPath query.

     * @param mixed    $data        A string or an array of strings. Each string

     *                              will replace an occurance of $placeholder

     *                              within $query. This argument is optional.

     * @param string   $placeholder The string to use as a placeholder. The default

     *                              is '?'. This argument is optional.

     */

    public function __construct(DOMXPath $xpath,

                                $query,

                                $data = null,

                                $placeholder = '?')

    {

        $this->_xpath = $xpath;

        $this->_query = $query;

        if (is_string($data)) {

            $this->_data = array($data);

        } elseif (is_array($data)) {

            $this->_data = $data;

        } else {

            // unit test: MISSING

            throw new XML_Query2XML_ConfigException(

                'XML_Query2XML_Data_Source_XPath::__construct(): '

                . 'array or string expected as third argument.'

            );

        }

        $this->_placeholder = $placeholder;

    }

    /**

     * Creates a new instance of this class.

     * This method is called by XML_Query2XML.

     *

     * @param string $stringDef  String definition.

     * @param string $configPath The configuration path within the $options array.

     *                           This argument is optional.

     *

     * @return void

     */

    public function create($stringDef, $configPath)

    {

        throw new XML_Query2XML_ConfigException(

            'XML_Query2XML_Data_Source_XPath::create() is not yet fully implemented'

        );

    }

    /**

     * Called by XML_Query2XML for every record in the result set.

     *

     * @param array $record An associative array.

     *

     * @return array An array of DOMNode instances.

     * @throws XML_Query2XML_ConfigException If any of the columns specified

     *                                       using the third constructor argument

     *                                       does not exist.

     */

    public function execute(array $record)

    {

        $data = array();

        foreach ($this->_data as $columnName) {

            if (array_key_exists($columnName, $record)) {

                $data[] = $record[$columnName];

            } else {

                // UNIT TEST: MISSING

                throw new XML_Query2XML_ConfigException(

                    'XML_Query2XML_Data_Source_XPath::execute(): The column "'

                    . $columnName . '" was not found in the result set.'

                );

            }

        }

        $query = self::_replacePlaceholders(

            $this->_query,

            $data,

            $this->_placeholder

        );

        $elements = array();

        $result   = @$this->_xpath->query($query);

        if ($result === false) {

            // UNIT TEST: MISSING

            throw new XML_Query2XML_XMLException(

                'XML_Query2XML_Data_Source_XPath::execute(): could not execute '

                . 'XPath query "' . $query . '"'

            );

        }

        foreach ($result as $element) {

            $elements[] = $element;

        }

        return $elements;

    }

    /**

     * Replaces all placeholder strings (e.g. '?') with replacement strings.

     *

     * @param string $string        The string in which to replace the placeholder

     *                              strings.

     * @param array  &$replacements An array of replacement strings.

     * @param string $placeholder   The placeholder string.

     *

     * @return string The modified version of $string.

     */

    private static function _replacePlaceholders($string,

                                                 &$replacements,

                                                 $placeholder)

    {

        while (($pos = strpos($string, $placeholder)) !== false) {

            if (count($replacements) > 0) {

                $string = substr($string, 0, $pos) .

                          array_shift($replacements) .

                          substr($string, $pos+strlen($placeholder));

            } else {

                break;

            }

        }

        return $string;

    }

    /**

     * This method is called by XML_Query2XML in case the asterisk shortcut was used.

     *

     * The interface XML_Query2XML_Data_Source requires an implementation of

     * this method.

     *

     * @param string $columnName The column name that is to replace every occurance

     *                           of the asterisk character ('*') in the second and

     *                           third argument passed to the constructor ($query

     *                           and $data).

     *

     * @return void

     */

    public function replaceAsterisks($columnName)

    {

        $this->_query = str_replace('*', $columnName, $this->_query);

        foreach ($this->_data as $key => $value) {

            $this->_data[$key] = str_replace('*', $columnName, $value);

        }

    }

    /**

     * Returns a textual representation of this instance.

     * This might be useful for debugging.

     *

     * @return string

     */

    public function toString()

    {

        return get_class($this) . '(' . $this->_query . ')';

    }

}

?>