<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category   Zend

 * @package    Zend_Search_Lucene

 * @subpackage Search

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 * @version    $Id: Empty.php 20096 2010-01-06 02:05:09Z bkarwin $

 */

/** Zend_Search_Lucene_Search_Query */

require_once 'Zend/Search/Lucene/Search/Query.php';

/**

 * @category   Zend

 * @package    Zend_Search_Lucene

 * @subpackage Search

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

class Zend_Search_Lucene_Search_Query_Empty extends Zend_Search_Lucene_Search_Query

{

    /**

     * Re-write query into primitive queries in the context of specified index

     *

     * @param Zend_Search_Lucene_Interface $index

     * @return Zend_Search_Lucene_Search_Query

     */

    public function rewrite(Zend_Search_Lucene_Interface $index)

    {

        return $this;

    }

    /**

     * Optimize query in the context of specified index

     *

     * @param Zend_Search_Lucene_Interface $index

     * @return Zend_Search_Lucene_Search_Query

     */

    public function optimize(Zend_Search_Lucene_Interface $index)

    {

        // "Empty" query is a primitive query and don't need to be optimized

        return $this;

    }

    /**

     * Constructs an appropriate Weight implementation for this query.

     *

     * @param Zend_Search_Lucene_Interface $reader

     * @return Zend_Search_Lucene_Search_Weight

     */

    public function createWeight(Zend_Search_Lucene_Interface $reader)

    {

        require_once 'Zend/Search/Lucene/Search/Weight/Empty.php';

        return new Zend_Search_Lucene_Search_Weight_Empty();

    }

    /**

     * Execute query in context of index reader

     * It also initializes necessary internal structures

     *

     * @param Zend_Search_Lucene_Interface $reader

     * @param Zend_Search_Lucene_Index_DocsFilter|null $docsFilter

     */

    public function execute(Zend_Search_Lucene_Interface $reader, $docsFilter = null)

    {

        // Do nothing

    }

    /**

     * Get document ids likely matching the query

     *

     * It's an array with document ids as keys (performance considerations)

     *

     * @return array

     */

    public function matchedDocs()

    {

        return array();

    }

    /**

     * Score specified document

     *

     * @param integer $docId

     * @param Zend_Search_Lucene_Interface $reader

     * @return float

     */

    public function score($docId, Zend_Search_Lucene_Interface $reader)

    {

        return 0;

    }

    /**

     * Return query terms

     *

     * @return array

     */

    public function getQueryTerms()

    {

        return array();

    }

    /**

     * Query specific matches highlighting

     *

     * @param Zend_Search_Lucene_Search_Highlighter_Interface $highlighter  Highlighter object (also contains doc for highlighting)

     */

    protected function _highlightMatches(Zend_Search_Lucene_Search_Highlighter_Interface $highlighter)

    {

        // Do nothing

    }

    /**

     * Print a query

     *

     * @return string

     */

    public function __toString()

    {

        return '<EmptyQuery>';

    }

}