Relationship API

relationship.class.php

<?php 
/**
 * @Author	Anonymous
 * @link http://www.redrokk.com
 * @Package Wordpress
 * @SubPackage Relationships
 * 
 * @version 2.0
 */

//security
defined('ABSPATH') or die('You\'re not supposed to be here.');

/**
 * 
 * 
 * @author Anonymous
 * @example

	$gallery = redrokk_relationship_class::getInstance('gallery');

 */
if (!class_exists('redrokk_relationship_class')):
class redrokk_relationship_class
{
	
	/**
	 *
	 * @var string
	 */
	protected $id;
	
	/**
	 * The different kinds of relationships that you can create with this system
	 *
	 * one-to-one
	 * one-to-many
	 * many-to-many
	 *
	 * @var string
	 */
	protected $type = 'many-to-many';
	
	/**
	 * post | taxonomy | user | comment
	 *
	 * @var string
	 */
	protected $left_type = false;
	
	/**
	 * clt name | term | comment | user
	 *
	 * @var string
	 */
	protected $left = 'post';
	
	/**
	 *
	 * @var string
	 */
	protected $right_type = false;
	
	/**
	 *
	 * @var string
	 */
	protected $right = 'post';
	
	/**
	 * 
	 * @var string
	 */
	protected $_table = 'relationships';
	
	/**
	 * Needs to be changed if the database table is ever changed.
	 * 
	 * @var string
	 */
	protected $_ver = '0.1';
	
	/**
	 * 
	 * @var string
	 */
	protected $_class;
	
	/**
	 * Constructor.
	 *
	 */
	function __construct( $options = array() )
	{
		// initializing
		$this->setProperties($options);
		
		// processing
		$this->update_check();
		$this->trigger_action();
		
		// hooks and filters
		add_filter( 'init', array($this, 'validate'), 50 );
		add_action( 'admin_init', array($this, 'init_metaboxes') );
		add_action( 'admin_head', array($this, 'css') );
		add_action( 'current_screen', array($this, 'init_user_metabox') );
		
		// @TODO create the query filter part
		//add_action( 'restrict_manage_posts', array($this, 'create_filter') );
		
	}
	
	/**
	 * 
	 */
	function setUnLinkRecord()
	{
		// initializing
		$direction = $_REQUEST['relationship_direction'];
		
		$left 	= $direction=='left' ?$_REQUEST['relationship_id']  :$_REQUEST['relationship_oid'];
		$right 	= $direction=='left' ?$_REQUEST['relationship_oid'] :$_REQUEST['relationship_id'];
		
		$this->setUnAssociation( $this->getObject( $left ), $this->getObject( $right, 'right' ) );
	}
	
	/**
	 * When one record exists and another is just being created
	 * 
	 * @param int $post_id
	 */
	function setLinkNewRecord( $post_id )
	{
		// initializing
		$direction = $_REQUEST['relationship_direction'];
		
		$left 	= $direction=='left' ?$post_id  					:$_REQUEST['relationship_id'];
		$right 	= $direction=='left' ?$_REQUEST['relationship_id']	:$post_id;
		$left_o = $this->getObject( $left );
		$right_o = $this->getObject( $right, 'right' );
		
		if ($this->areRelated($left_o, $right_o)) return;
		$this->setAssociation( $left_o, $right_o );
	}
	
	/**
	 * When both records already exist
	 * 
	 */
	function setLinkExistingRecord()
	{
		// initializing
		$direction = $_REQUEST['relationship_direction'];
		
		$left 	= $direction=='left' ?$_REQUEST['relationship_id']  :$_REQUEST['relationship_oid'];
		$right 	= $direction=='left' ?$_REQUEST['relationship_oid'] :$_REQUEST['relationship_id'];
		$left_o = $this->getObject( $left );
		$right_o = $this->getObject( $right, 'right' );
		
		if ($this->areRelated($left_o, $right_o)) return;
		$this->setAssociation( $left_o, $right_o );
	}
	
	/**
	 *
	 * @param object $obj1
	 * @param object $obj2
	 */
	function setAssociation( $obj1, $obj2 )
	{
		// initializing
		global $wpdb;
	
		if ($this->getDirection( $obj1 ) == 'left') {
			$left_id = $this->getObjectID( $obj1 );
			$right_id = $this->getObjectID( $obj2 );
				
		} else {
			$left_id = $this->getObjectID( $obj2 );
			$right_id = $this->getObjectID( $obj1 );
				
		}
	
		$query = "INSERT INTO `".$wpdb->prefix.$this->_table."` "
				."( `left_object_type`, `left_object`, `left_id`, `right_object_type`, `right_object`, `right_id` ) VALUES"
				."( '".$this->left_type."', '".$this->left."', '".$left_id."',"
				."'".$this->right_type."', '".$this->right."', '".$right_id."' );";
	
		return $wpdb->query( $query );
	}
	
	/**
	 *
	 * @param object $o
	 */
	function getDirection( $o )
	{
		if ($this->left_type == $this->getObjectType( $o ) && $this->left == $this->getObjectName( $o )) {
			return 'left';
		}
		return 'right';
	}
	
	/**
	 *
	 * @param object $obj1
	 * @param object $obj2
	 */
	function setUnAssociation( $obj1, $obj2 )
	{
		// initializing
		global $wpdb;
		
		if ($this->getDirection( $obj1 ) == 'left') {
			$left_id = $this->getObjectID( $obj1 );
			$right_id = $this->getObjectID( $obj2 );
				
		} else {
			$left_id = $this->getObjectID( $obj2 );
			$right_id = $this->getObjectID( $obj1 );
				
		}
		
		$query 	= "DELETE FROM `".$wpdb->prefix.$this->_table."` "
				. " WHERE ("
					. " `left_object_type` = '$this->left_type' "
					. " AND `left_object` = '$this->left' "
					. " AND `left_id` = '$left_id' "
					. " AND `right_object_type` = '$this->right_type' "
					. " AND `right_object` = '$this->right' "
					. " AND `right_id` = '$right_id' "
				. ") OR ("
					. " `left_object_type` = '$this->right_type' "
					. " AND `left_object` = '$this->right' "
					. " AND `left_id` = '$right_id' "
					. " AND `right_object_type` = '$this->left_type' "
					. " AND `right_object` = '$this->left' "
					. " AND `right_id` = '$left_id' "
				. ")";
	
		$results = $wpdb->query( $query );
		return $results;
	}
	
	/**
	 * 
	 * @param unknown_type $o
	 */
	function areRelated( $o, $o1 )
	{
		global $wpdb;
		$id = $this->getObjectID($o);
		$type = $this->getObjectType($o);
		$object = $this->getObjectName($o);
		
		$id1 = $this->getObjectID($o1);
		$type1 = $this->getObjectType($o1);
		$object1 = $this->getObjectName($o1);
		
		$q = "SELECT * FROM `{$wpdb->prefix}".$this->_table."` WHERE "
			."( `left_object_type` = '$type' AND `left_object` = '$object' AND `left_id` = '$id' "
			." AND `right_object_type` = '$type1' AND `right_object` = '$object1' AND `right_id` = '$id1' )"
			."OR"
			."( `right_object_type` = '$type' AND `right_object` = '$object' AND `right_id` = '$id' "
			." AND `left_object_type` = '$type1' AND `left_object` = '$object1' AND `left_id` = '$id1' )";
		
		// requirements
		if (!$results = $wpdb->get_results( $q )) return false;
		return true;
	}
	
	/**
	 * Method returns all of the linked objects
	 *
	 * @param object|int $o
	 */
	function getRelated( $o )
	{
		// initializing
		global $wpdb;
		$objects = array();
		$id = $this->getObjectID($o);
		$type = $this->getObjectType($o);
		$object = $this->getObjectName($o);
		$direction = $this->getDirection($o);
		$opposite = $direction == 'left' ?'right' :'left';
		
		if ($direction == 'left') {
			$q = "SELECT `right_id` as `id` FROM `{$wpdb->prefix}".$this->_table."` WHERE "
				."( `left_object_type` = '$type' AND `left_object` = '$object' AND `left_id` = '$id' "
				."AND "
				." `right_object_type` = '{$this->right_type}' AND `right_object` = '{$this->right}' )";
			
		} else {
			$q = "SELECT `left_id` as `id` FROM `{$wpdb->prefix}".$this->_table."` WHERE "
				."( `right_object_type` = '$type' AND `right_object` = '$object' AND `right_id` = '$id' "
				."AND "
				." `left_object_type` = '{$this->left_type}' AND `left_object` = '{$this->left}' )";
			
		}
		
		// requirements
		if (!$results = $wpdb->get_results( $q )) return false;
		
		foreach ((array)$results as $result)
		{
			$object = $this->getObject( $result->id, $opposite );
			if (!$object) continue;
			if (!$this->getObjectID( $object )) continue;
			
			$objects[] = $object;
		}
		
		if (empty($objects))
			return false;
		
		return $objects;
	}
	
	/**
	 * Adds the columns
	 *
	 * @param $columns
	 */
	function create_columns( $columns )
	{
		// initializing
		global $post;
		$opposite = $_REQUEST['relationship_direction'] == 'left' ?'right' :'left';
		$type = $opposite.'_type';
		
		if (get_role( $this->$opposite ) !== null 
		|| taxonomy_exists( $this->$opposite )) {
			$name = ucwords($this->$opposite);
		
		} elseif (post_type_exists( $this->$opposite ))  {
			$postType = get_post_type_object($this->$type);
			$name = $postType->labels->name;
		}
		
		$newColumns = array('cb' => $columns['cb'] );
		$newColumns['relationship_button'] = 'Actions';
		$newColumns = $newColumns + $columns;
		$newColumns['relationship_association'] = $name.' Association';
	
		if (array_key_exists('author', $columns))
		{
			$tmp = $newColumns['author'];
			unset($newColumns['author']);
			$newColumns['author'] = $tmp;
		}
	
		if (array_key_exists('date', $columns))
		{
			$tmp = $newColumns['date'];
			unset($newColumns['date']);
			$newColumns['date'] = $tmp;
		}
	
		return $newColumns;
	}
	
	/**
	 * 
	 * 
	 * @param string $column_id
	 * @return boolean
	 */
	function table_user_columns( $empty = '', $column_id, $oid )
	{
		ob_start();
		
		// initializing
		global $post;
		$direction = $_REQUEST['relationship_direction'];
		$opposite = $direction == 'left' ?'right' :'left';
		$id = $_REQUEST['relationship_id'];
		
		switch ($column_id) {
			case 'relationship_button':
				echo '<a class="preview button" href="'.$this->get_link('link', $opposite, $id, $oid).'">Link Record</a>';
				
			break;
			case 'relationship_association':
				$children = $this->getObject( $oid, $direction );
				//@TODO show a csv list of related items
				
			break;
		}
		
		return ob_get_clean();
	}
	
	/**
	 * 
	 * 
	 * @param string $column_id
	 * @return boolean
	 */
	function table_columns( $column_id )
	{
		// initializing
		global $post;
		$direction = $_REQUEST['relationship_direction'];
		$opposite = $direction == 'left' ?'right' :'left';
		$id = $_REQUEST['relationship_id'];
		
		switch ($column_id) {
			case 'relationship_button':
				echo '<a class="preview button" href="'.$this->get_link('link', $opposite, $id, $post->ID).'">Link Record</a>';
				
			break;
			case 'relationship_association':
				$children = $this->getRelated( $post );
				//@TODO show a csv list of related items
				
			break;
		}
	}
	
	/**
	 * Method displays the css
	 * 
	 */
	function css()
	{
		?>
		<style type="text/css">
		#<?php echo $this->id; ?> table.relationship_table th, 
 		#<?php echo $this->id; ?> table.relationship_table td { text-align:left;margin:0;padding:0; } 
		#<?php echo $this->id; ?> table.relationship_table th, 
 		#<?php echo $this->id; ?> table.relationship_table { margin:0;padding:0;border-spacing: 0; } 
		#<?php echo $this->id; ?> .autogenerated-metabox {margin:0px;}
		#<?php echo $this->id; ?> .autogenerated-metabox td {padding:0px;}
		#<?php echo $this->id; ?> .inside {margin:0 0 30px;}
		#<?php echo $this->id; ?> .thead {background:#DFDFDF url(<?php bloginfo('url'); ?>/wp-admin/images/gray-grad.png) 0 0 repeat-x;line-height:20px;}
		#<?php echo $this->id; ?> .thead th {padding:5px !important;width:200px;}
		#<?php echo $this->id; ?> .relationship_table td {padding:3px !important;}
		#<?php echo $this->id; ?> .relationship_actions {width:50px !important;}
		#<?php echo $this->id; ?> table.relationship_table td {border-bottom:1px solid #eee;padding-bottom:20px;margin-bottom:10px;}
		#<?php echo $this->id; ?> table.relationship_table {width: 100%;border-bottom:1px solid #ccc;padding-bottom:20px;margin-bottom:10px;}
		#<?php echo $this->id; ?> #<?php echo $this->id; ?>-table-ID {width:50px !important;}
		#<?php echo $this->id; ?> h3.hndle {background-color: #636363;background-image: url(<?php bloginfo('url'); ?>/wp-admin/images/fav.png);border-color: #636363;color: white;text-shadow: #3F3F3F 0px -1px 0px;}
		#<?php echo $this->id; ?>:hover .handlediv {cursor:pointer;background: transparent url(<?php bloginfo('url'); ?>/wp-admin/images/widgets-arrow.gif) no-repeat scroll 0px -1px;}
		#relationship_button { width:85px; }
		</style>
		<?php 
	}
	
	/**
	 * Method creates a filter select input
	 * 
	 */
	function create_filter()
	{
		$opposite = $_REQUEST['relationship_direction'] == 'left' ?'right' :'left';
		
		?>
		<label>
			<input type="checkbox" name="relationship_filter" value="<?php echo $opposite ?>" />
			Filter by <?php echo ucwords($this->$opposite) ?> Associations
		</label>
		<input type="hidden" name="redrokk_relationship_class" value="<?php echo $this->id ?>" />
		<input type="hidden" name="relationship_id" value="<?php echo $_REQUEST['relationship_id'] ?>" />
		<input type="hidden" name="relationship_action" value="<?php echo $_REQUEST['relationship_action'] ?>" />
		<input type="hidden" name="relationship_direction" value="<?php echo $_REQUEST['relationship_direction'] ?>" />
		<?php 
	}
	
	/**
	 * 
	 */
	function init_metaboxes()
	{
		// Add the left metabox
		if ($this->get_current_type() == $this->right) {
			add_meta_box(
				$this->id,
				'Related '.ucwords($this->left),
				array($this, 'metabox'),
				$this->right,
				'normal',
				'default',
				'left'
			);
		}
		
		// Add the right metabox
		elseif ($this->get_current_type() == $this->left) {
			add_meta_box(
				$this->id,
				'Related '.ucwords($this->right),
				array($this, 'metabox'),
				$this->left,
				'normal',
				'default',
				'right'
			);
		}
	}
	
	/**
	 * The related node listings on the users page
	 * 
	 */
	function metabox_user( $user )
	{
		//initializing
		$direction = $this->getDirection( $user );
		$params = array();
		$opposite = $params['args'] = $direction == 'left' ?'right' :'left';
		$property = $opposite.'_type';
		$p = $this->$property;
		
		?>
		<h3>Related <?php echo ucwords($p) ?></h3>
		<div id="<?php echo $this->id ?>">
			<?php $this->metabox( $user, $params ); ?>
		</div>
		<?php 
	}
	
	/**
	 * The related bode listings
	 * 
	 */
	function metabox( $current, $params = array() )
	{
		//initializing
		$direction = $params['args'];
		$opposite = $direction == 'left' ?'right' :'left';
		$children = $this->getRelated( $current );
		$columns = array(
			'post'	=> array('post_title' => 'Title','post_type' => 'Post Type', 'post_status' => 'Status'),
			'user'	=> array('display_name' => 'User', 'user_email' => 'Email', 'role' => 'Role','user_status' => 'Status' )
		);
		
		?>
			<a name="<?php echo $this->id; ?>"></a>
			
			<?php if (!is_array($children)): ?>
			<p>There are no relationships at this time. 
				<a class="preview button" href="<?php echo $this->get_link('new', $direction, $current->ID); ?>">New Record</a>
				<a style="margin-right:10px;" class="preview button" href="<?php echo $this->get_link('existing', $direction, $current->ID); ?>">Link Record</a>
			</p>
			
			<?php else: 
			// Getting the headers
			$type = $this->getObjectType( $children[0] );
			$columns = apply_filters("{$this->id}-$direction-headers", $columns[$type]);
			
			?>
			<table class="relationship_table">
				<tr class="thead">
					<?php foreach ($columns as $property => $title): ?>
					<th class="<?php echo $this->id; ?>-<?php echo $property; ?>">
						<?php echo $title; ?>
					</th>
					<?php endforeach; ?>
					<th class="relationship_actions">Actions</th>
				</tr>
				
				<?php foreach ($children as $child): ?>
				<tr>
					<?php foreach ($columns as $property => $title): ?>
					<td>
						<?php 
						switch ($property)
						{
							default: echo $child->$property; break;
							case 'display_name':
								 echo '<a href="'. admin_url('user-edit.php?user_id='.$child->ID) .'">'.
								 $child->$property.'</a>';
								 break;
							case 'post_title': 
								echo '<a href="'. admin_url('post.php?post='.$child->ID.'&action=edit') .'">'.
								$child->$property.'</a>'; 
								break;
							case 'post_date': 
								echo date('M jS Y', strtotime($child->$property)); 
								break;
							case 'role': 
								echo $child->roles[0]; 
								break;
						}
						?>
					</td>
					<?php endforeach; ?>
					<td>
						<a class="preview button" href="<?php echo $this->get_link('unlink', $opposite, $current->ID, $child->ID); ?>">Unlink</a>
					</td>
				</tr>
				<?php endforeach; ?>
				
			</table>
			
			<div style="margin-right:20px;">
				<a class="preview button" href="<?php echo $this->get_link('new', $direction, $current->ID); ?>">New Record</a>
				<a style="margin-right:10px;" class="preview button" href="<?php echo $this->get_link('existing', $direction, $current->ID); ?>">Link Record</a>
			</div>
			<div style="width:100%;display:block;clear:both;"></div>
			
			<?php endif;
	}
	
	/**
	 * Echo new relationship link
	 *
	 * Function is responsible for creating this link and echoing it
	 * 
	 * 
	 */
	function get_link( $action = 'new', $direction = 'left', $lid = false, $rid = false )
	{
		$args = array(
			'redrokk_relationship_class'=> $this->id,
			'relationship_action'		=> $action,
			'relationship_direction'	=> $direction
		);
		
		if ($lid) {
			$args['relationship_id'] = $lid;
		}
		if ($rid) {
			$args['relationship_oid'] = $rid;
		}
		
		switch ($action.'_'.$this->getType( $direction )) 
		{
			// Creating new nodes from metabox
			default:
			case 'new_post':
				$href = admin_url('post-new.php?post_type='.$this->$direction);
				break;
			case 'new_user':
				$href = admin_url('user-new.php');
				break;
			
			// Existing nodes from metabox to open listing
			case 'existing_post':
				$href = admin_url('edit.php?post_type='.$this->$direction);
				break;
			case 'existing_user':
				$href = admin_url('users.php');
				break;
			
			// Unlinking a relationship from metabox and listing
			case 'unlink_post':
				$href = admin_url('post.php?action=edit&post='.$lid);
				break;
			case 'unlink_user':
				$href = admin_url('user-edit.php?user_id='.$lid);
				break;
			
			// linking a new relationship from listing
			case 'link_post':
				$href = admin_url('post.php?action=edit&post='.$lid);
				break;
			case 'link_user':
				$href = admin_url('user-edit.php?user_id='.$lid);
				break;
		}
		
		return add_query_arg($args, $href);
	}
	
	/**
	 * Method sets catches the requested actions and processes any new hooks for those actions.
	 *
	 */
	function trigger_action()
	{
		// requirements
		if (!array_key_exists('redrokk_relationship_class', $_REQUEST)) return false;
		if (!array_key_exists('relationship_action', $_REQUEST)) return false;
		if ($_REQUEST['redrokk_relationship_class'] !== $this->id) return false;
	
		// initializing
		$direction = $_REQUEST['relationship_direction'];
		$opposite = $direction == 'left' ?'right' :'left';
	
		// hooks and filters
		switch ($_REQUEST['relationship_action']) {
			default:
			case 'existing':
				add_filter( "manage_edit-{$this->$direction}_columns", array($this, 'create_columns'), 10, 1);
				add_filter( 'manage_users_columns', array($this, 'create_columns'), 10, 1);
				
				add_action( 'manage_users_custom_column', array($this, 'table_user_columns'), 20, 3 );
				add_action( 'manage_posts_custom_column', array($this, 'table_columns'), 20, 1 );
				add_action( 'manage_pages_custom_column', array($this, 'table_columns'), 20, 1 );
				break;
			case 'link':
				add_action( 'init', array($this, 'setLinkExistingRecord'), 60 );
				break;
			case 'unlink':
				add_action( 'init', array($this, 'setUnLinkRecord'), 60 );
				break;
				
			// creating 
			case 'new':
				add_action( 'dbx_post_sidebar', array($this, 'doNewActionInputs'), 100 );
				break;
			case 'new-saved':
				add_action( 'save_post', array($this, 'setLinkNewRecord'), 60 );
				break;
		}
	}
	
	/**
	 *
	 * @return unknown
	 */
	function get_current_type()
	{
		if (isset($_GET['post'])) {
			return get_post_type( get_post($_GET['post']) );
		}
	}
	
	/**
	 *
	 */
	function init_user_metabox()
	{
		if ( get_current_screen() === NULL ) return false;
		if ( get_current_screen()->base !== 'user-edit' ) return false;
	
		add_action( 'edit_user_profile', array($this, 'metabox_user') );
	}
	
	/**
	 *
	 */
	function doNewActionInputs()
	{
		?>
			<input type="hidden" name="redrokk_relationship_class" value="<?php echo $this->id ?>" />
			<input type="hidden" name="relationship_id" value="<?php echo $_REQUEST['relationship_id'] ?>" />
			<input type="hidden" name="relationship_action" value="new-saved" />
			<input type="hidden" name="relationship_direction" value="<?php echo $_REQUEST['relationship_direction'] ?>" />
		<?php 
	}
	
	/**
	 * 
	 * @param object $o
	 */
	function getObjectType( $o )
	{
		if (isset( $o->term_id )) {
			return 'taxonomy';
			
		} elseif (isset( $o->post_type )) {
			return 'post';
			
		} elseif (is_a($o, 'WP_User')) {
			return 'user';
			
		}
	}
	
	/**
	 * 
	 * @param object $o
	 */
	function getObjectName( $o )
	{
		switch ($this->getObjectType( $o ))
		{
			default:
			case 'post':
				return $o->post_type;
				break;
			case 'user':
				return 'user';
				break;
			case 'taxonomy':
				// @todo return taxonomy name or term name?
				break;
		}
	}
	
	/**
	 *
	 * @param unknown_type $direction
	 */
	function getType( $direction = 'left' )
	{
		$type = $direction.'_type';
		return $this->$type;
	}
	
	/**
	 *
	 * @param unknown_type $id
	 * @param unknown_type $direction
	 */
	function getObject( $id, $direction = 'left' )
	{
		switch($this->getType( $direction ))
		{
			default:
			case 'post':
				return get_post( $id );
				break;
			case 'user':
				return new WP_User( $id );
				break;
			case 'taxonomy':
				return get_term( $id, $this->$direction, ARRAY_A );
				break;
		}
		return false;
	}
	
	/**
	 *
	 * @param unknown_type $o
	 */
	function getObjectID( $o )
	{
		if (isset( $o->ID )) {
			return $o->ID;
			
		} elseif (isset( $o->term_id )) {
			return $o->term_id;
			
		}
	
	}
	
	/**
	 * Runs any final validation before we get to work
	 * 
	 */
	function validate()
	{
		// set the proper objects
		if (is_wp_error( $e = $this->setType( ) )) {
			// @TODO do error display
		}
		if (is_wp_error( $e = $this->setType( 'right' ) )) {
			// @TODO do error display
		}
	}
	
	/**
	 * Method makes sure that the objects are set properly
	 * 
	 * @param string $direction
	 * @return WP_Error|boolean
	 */
	function setType( $direction = 'left' )
	{
		// initializing
		$property = $direction.'_type';
		
		if (!$this->$property) {
			if (get_role( $this->$direction ) || $this->$direction == 'user') {
				$this->$property = 'user';
			
			} elseif (taxonomy_exists( $this->$direction )) {
				$this->$property = 'taxonomy';
			
			} elseif (post_type_exists( $this->$direction )) {
				$this->$property = 'post';
				
			} else {
				return new WP_Error('broke', __("redrokk_relationship_class : Bad Configuration, the $direction object type is unknown."));
			}
		}
		
		return true;
	}
	
	/**
	 * Method makes sure that the table is up to date for this class
	 * 
	 */
	function update_check() 
	{
		if (get_site_option('redrokk_relationship_class::_ver') == $this->_ver) 
			return true;
		
		return $this->create_table();
	}
	
	/**
	 * Creates `relationship` table if it doesn't exist
	 *
	 */
	function create_table()
	{
		// initializing
		global $wpdb;
		require_once(ABSPATH . 'wp-admin/includes/upgrade.php');
		
		if (!empty ($wpdb->charset))
			$charset_collate = "DEFAULT CHARACTER SET {$wpdb->charset}";
		
		if (!empty ($wpdb->collate))
			$charset_collate .= " COLLATE {$wpdb->collate}";
		
		// creating the table
		$sql = "CREATE TABLE IF NOT EXISTS `{$wpdb->prefix}{$this->_table}` (
			id int(11) NOT NULL AUTO_INCREMENT,
			left_object_type varchar(32) NOT NULL,
			left_object varchar(32) NOT NULL,
			left_id int(11) NOT NULL,
			right_object_type varchar(32) NOT NULL,
			right_object varchar(32) NOT NULL,
			right_id int(11) NOT NULL,
			UNIQUE KEY id (id)
		) {$charset_collate};";
		
		$wpdb->query($sql);
		update_option( "redrokk_relationship_class::_ver", $this->_ver );
		
		return true;
	}
	
	/**
	 * 
	 * @return string
	 */
	function get_current_url()
	{
		return 'http'.((!empty($_SERVER['HTTPS']))?'s':'').'://'.$_SERVER['SERVER_NAME'].$_SERVER['REQUEST_URI'];
	}
	
	/**
	 * Method to bind an associative array or object to the JTable instance.This
	 * method only binds properties that are publicly accessible and optionally
	 * takes an array of properties to ignore when binding.
	 *
	 * @param   mixed  $src	 An associative array or object to bind to the JTable instance.
	 * @param   mixed  $ignore  An optional array or space separated list of properties to ignore while binding.
	 *
	 * @return  boolean  True on success.
	 *
	 * @link	http://docs.joomla.org/JTable/bind
	 * @since   11.1
	 */
	public function bind($src, $ignore = array())
	{
		// If the source value is not an array or object return false.
		if (!is_object($src) && !is_array($src))
		{
			trigger_error('Bind failed as the provided source is not an array.');
			return false;
		}
	
		// If the source value is an object, get its accessible properties.
		if (is_object($src))
		{
			$src = get_object_vars($src);
		}
	
		// If the ignore value is a string, explode it over spaces.
		if (!is_array($ignore))
		{
			$ignore = explode(' ', $ignore);
		}
	
		// Bind the source value, excluding the ignored fields.
		foreach ($this->getProperties() as $k => $v)
		{
			// Only process fields not in the ignore array.
			if (!in_array($k, $ignore))
			{
				if (isset($src[$k]))
				{
					$this->$k = $src[$k];
				}
			}
		}
	
		return true;
	}
	
	/**
	 * Set the object properties based on a named array/hash.
	 *
	 * @param   mixed  $properties  Either an associative array or another object.
	 *
	 * @return  boolean
	 *
	 * @since   11.1
	 *
	 * @see	 set()
	 */
	public function setProperties($properties)
	{
		if (is_array($properties) || is_object($properties))
		{
			foreach ((array) $properties as $k => $v)
			{
				// Use the set function which might be overridden.
				$this->set($k, $v);
			}
			return true;
		}
	
		return false;
	}
	
	/**
	 * Modifies a property of the object, creating it if it does not already exist.
	 *
	 * @param   string  $property  The name of the property.
	 * @param   mixed   $value	 The value of the property to set.
	 *
	 * @return  mixed  Previous value of the property.
	 *
	 * @since   11.1
	 */
	public function set($property, $value = null)
	{
		$_property = 'set'.str_replace(' ', '', ucwords(str_replace('_', ' ', $property)));
		if (method_exists($this, $_property)) {
			return $this->$_property($value);
		}
	
		$previous = isset($this->$property) ? $this->$property : null;
		$this->$property = $value;
		return $previous;
	}
	
	/**
	 * Returns an associative array of object properties.
	 *
	 * @param   boolean  $public  If true, returns only the public properties.
	 *
	 * @return  array
	 *
	 * @see	 get()
	 */
	public function getProperties($public = true)
	{
		$vars = get_object_vars($this);
		if ($public)
		{
			foreach ($vars as $key => $value)
			{
				if ('_' == substr($key, 0, 1))
				{
					unset($vars[$key]);
				}
			}
		}
	
		return $vars;
	}
	
	/**
	 * Method returns the called class
	 *
	 */
	public static function get_called_class()
	{
		if (function_exists('get_called_class')) {
			return get_called_class();
		}
	
		$called_class = false;
		$objects = array();
		$traces = debug_backtrace();
		foreach ($traces as $trace)
		{
			if (isset($trace['object'])) {
				if (is_object($trace['object'])) {
					$objects[] = $trace['object'];
				}
			}
		}
	
		if (count($objects)) {
			$called_class = get_class($objects[0]);
		}
	
		return $called_class;
	}
	
	/**
	 *
	 * contains the current instance of this class
	 * @var object
	 */
	static $_instances = null;
	
	/**
	 * Method is called when we need to instantiate this class
	 *
	 * @param array $options
	 */
	public static function getInstance( $id, $options = array() )
	{
		if (!isset(self::$_instances[$id]))
		{
			$class = self::get_called_class();
			$options['_class'] = $class;
			$options['id'] = $id;
	
			self::$_instances[$id] =& new $class($options);
		}
		return self::$_instances[$id];
	}
}
endif;