Source for file MenuTheme.abstract.php

<?php
 
require_once(HARMONI."GUIManager/Theme.class.php");
 
/**
 * This MenuTheme abstract class implements solely the <code>addMenu</code> and <code>getMenu</code>
 * methods. If the user desires a proper complete implementation of the <code>MenuTheme</code>
 * interface, then there are two ways of doing that:<br /><br />
 * <ol>
 *      <li> The user could overload setMenu so that as a new menu is added,
 *         it is appropriately incorporated in a <code>Container</code> along with
 *      the <code>Theme</code> component and all other previously added menus.
 *         This is the recommended solution.
 *      </li>
 *         <li> The user could overload root Theme methods (at least <code>printPage()</code>) to
 *         account for added menus. In other words, HTML generating methods will
 *      dynamically generate menu-related output as they are called.
 *         </li>
 * </ol>
 * <br />
 * 
 * A <code>MenuTheme</code> is an extension of the generic <code>Theme</code> interface
 * that adds support for multi-level navigation menus. A <code>MenuTheme</code>,
 * like a normal </code>Theme</code> has a single <code>Component</code>; however,
 * it allows the user to surround that component with multi-level navigation menus.
 *
 * @package harmoni.gui
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: MenuTheme.abstract.php,v 1.5 2007/09/04 20:25:21 adamfranco Exp $
 ***/
class MenuThemeAbstract extends Theme /* implements MenuThemeInterface */ {
    
    /**
     * An array storing all menus of this theme. Each element is a <code>Menu</code>
     * object.
     * @attribute private array _menus
     */
    var $_menus;
    
    /**
     * Adds a new menu to this theme.
     * @access public
     * @param ref object menu A <code>Menu</code> object to be added to this theme.
     * @param integer level A positive integer specifying the <code>level</code> of the
     *  menu that is being added. Only one menu can exist at any given level.
     *  Levels cannot be skipped. Levels allow the user to create a hierarchy of menus.
     ***/
    function addMenu($menu, $level) {
        // ** parameter validation
        ArgumentValidator::validate($menu, ExtendsValidatorRule::getRule("Menu"), true);
        $greaterThanZero = $level > 0;
        ArgumentValidator::validate($greaterThanZero, TrueValidatorRule::getRule(), true);
        // ** end of parameter validation        
        
        // two things need to be true in order for this menu to be added
        // 1) no levels before the given are empty
        // 2) no menu has been set for this level already
        if ($level > 1 && !isset($this->_menus[$level-1])) {
            $err = "Error when adding a menu to a theme: all prior menu levels must be non-empty.";
            throwError(new Error($err, "GUIManager", false));
            return;            
        }
        if (isset($this->_menus[$level])) {
            $err = "A menu has already been set for the given level.";
            throwError(new Error($err, "GUIManager", false));
            return;            
        }
        
        // now add the menu
        $this->_menus[$level] =$menu;
    }
    
    /**
     * Returns the menu (if exists) at the given level.
     * @access public
     * @param integer level An integer specifying the <code>level</code> of the
     *  menu that is to be returned. Levels start at 1. Only one menu can exist at any given level.
     *  Levels cannot be skipped. Levels allow the user to create a hierarchy of menus.
     * @return ref object The <code>Menu</code> object at the specified level, or <code>NULL</code>
     *  if no menu was found.
     ***/
    function getMenu($level) {
        // ** parameter validation
        $greaterThanZero = $level > 0;
        ArgumentValidator::validate($greaterThanZero, TrueValidatorRule::getRule(), true);
        // ** end of parameter validation        
        
        if (isset($this->_menus[$level]))
            return $this->_menus[$level];
        else
            return null;
    }
    
    
    /**
     * Returns the number of menus in this Theme.
     * @access public
     * @return integer The number of menus.
     ***/
    function getNumberOfMenus() {
        return count($this->_menus);
    }
    
    
}
 
?>