source: Dev/trunk/rdfapi/dataset/Quad.php @ 12

<?php
// ----------------------------------------------------------------------------------
// Class: Quad
// ----------------------------------------------------------------------------------

/**
*
* A Triple in a RDF dataset, consisting of four Jena Nodes: graphName,
* subject, predicate, and object.
*
* @version  $Id$
* @author Daniel Westphal (http://www.d-westphal.de)
*
* @package      dataset
* @access       public
**/
class Quad  
{
        
        /**
        * Name of the NamedGraphMem.
        *
        * @var          Resource
        * @access       private
        */
        var $graphName;
        
        /**
        * Statement
        *
        * @var          Statement
        * @access       private
        */
        var $statement;
        
        /**
    * Constructor
        * Creates a Quad from four Nodes.
        *
    * @param Resource 
    * @param Resource  
    * @param Resource  
    * @param Resource   
        * @access       public
    */          
        function Quad($graphName,$subject,$predicate,$object)
        {
                if (!is_a($graphName, 'Resource')) 
                {
                        $errmsg = RDFAPI_ERROR . 
                          '(class: Quad; method: new): Resource expected as graphName.';
                        trigger_error($errmsg, E_USER_ERROR); 
                }
                $this->statement=new Statement($subject,$predicate,$object);
                $this->graphName=$graphName;
        }
        
        /**
    * Sets the graph name.
    *
    * @param Resource  
        * @access       public
    */  
        function setGraphName($graphName)
        {
                $this->graphName=$graphName;
        }
        
        /**
    * Returns the graph name.
    *
    * @return Resource
        * @access       public
    */
        function getGraphName()
        {
                return $this->graphName;
        }
        
        /**
         * Return a human-readable (sort of) string "graphname { s p o . }"
         * describing the quad.
         *
         * @return string
         */
        function toString() 
        {       
                return 'GraphName('.$this->graphName->getLabel().') '.$this->statement->toString();
        }
                
        /**
    * Returns the subject.
    *
    * @return Resource
        * @access       public
    */
        function getSubject()
        {
                return $this->statement->getSubject();  
        }
                
        /**
    * Returns the predicate.
    *
    * @return Resource
        * @access       public
    */
        function getPredicate()
        {
                return $this->statement->getPredicate();        
        }
                
        /**
    * Returns the object.
    *
    * @return Resource
        * @access       public
    */
        function getObject()
        {
                return $this->statement->getObject();   
        }
                
        /**
    * Returns the statement(subject,predicate,object).
    *
    * @return statement
        * @access       public
    */
        function getStatement()
        {
                return $this->statement;        
        }
                
        /**
    * Checks if two quads are equal.
    *
    * @param  Quad
    * @return boolean
        * @access       public
    */
        function equals($quad)
        {
                return ($this->graphName->equals($quad->getGraphName()) && $this->statement->equals($quad->getStatement()));    
        }
}
?>