Edit

<?php

// $Id$

/**

* Copyright (C) 2007 EDIT

* European Distributed Institute of Taxonomy 

* http://www.e-taxonomy.eu

* 

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See http://www.mozilla.org/MPL/MPL-1.1.html for the full license terms.

*/

class FootnoteManager

{

    private static $fnstore = array();

    private static $nextFootnoteKey = 1;

    // private constructor

    private function __construct() {

    }

    /**

     * @param $footnoteListKey a string as key to the list of footnotes

     * @return an array of footnotes objects

     *  

     */

    public static function getFootnoteList($footnoteListKey){

      return array_key_exists($footnoteListKey, self::$fnstore) ? self::$fnstore[$footnoteListKey] : NULL;

    }

    /**

     * 

     * @param $footnoteListKey

     * @param $separator

     * @return unknown_type

     */

    public static function renderFootnoteList($footnoteListKey, $separator = ', '){

      $out = '';

      if(array_key_exists($footnoteListKey, self::$fnstore)){

        foreach(self::$fnstore[$footnoteListKey] as $fn){

          $out .= $fn->doRender() . $separator;

        }

        $out = substr($out, 0, strlen($out)-strlen($separator));

      }

      return $out;

    }

    /**

     * 

     * @param $footnoteListKey

     * @param $object

     * @param $theme

     * @param $themeArguments

     * @return unknown_type

     */

    public static function addNewFootnote($footnoteListKey, $object, $theme = NULL, $themeArguments = array()){

      if(!array_key_exists($footnoteListKey, self::$fnstore)){

          self::$fnstore[$footnoteListKey] = array();

      }

      $fnKey = NULL;

      if( !($fnKey = self::footnoteExists($footnoteListKey, $object)) ){

        $fnKey = self::$nextFootnoteKey++;

        $fn = new Footnote($fnKey, $object, $theme, $themeArguments);

        self::$fnstore[$footnoteListKey][$fnKey] = $fn;

      }

      return $fnKey;

    }

    /**

     * 

     * @param $footnoteListKey

     * @param $object

     * @return unknown_type

     */

    private static function footnoteExists($footnoteListKey, $object){

      foreach(self::$fnstore[$footnoteListKey] as $key=>$fn){

        /**

         * When using the comparison operator (==), object variables are compared in a simple manner, namely: 

         * Two object instances are equal if they have the same attributes and values, and are instances of the same class. 

         */

        if($object == $fn->object){

          return $key;

        }

      }

      return FALSE;

    }

    // stop users from cloning

    public function __clone() {

        trigger_error('Cloning instances of the singleton class FootNoteManager is prohibited', E_USER_ERROR);

    }

}