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

<?php 
//----------------------------------------------------------------------------------
// Class: IteratorFindQuadsDb
// ----------------------------------------------------------------------------------


/**
* Implementation of a quad iterator.
*
* This Iterator should be used like:
* for($iterator = $dataset->findInNamedGraphs(null,null,null,null); $iterator->valid(); $iterator->next()) 
* {
*       $currentQuad=$iterator->current();
* };
*
*
* @version  $Id$
* @author Daniel Westphal (http://www.d-westphal.de)
*
*
* @package      dataset
* @access       public
**/
class IteratorFindQuadsDb
{
        /**
        * Holds a reference to the associated DB resultSet.
        *
        * @var          $dbResultSets ADODB result
        * @access       private
        */
        var $dbResultSet;
        
        /**
        * Holds a reference to the associated datasetDb.
        *
        * @var          $datasetDb datasetDb
        * @access       private
        */
        var $datasetDb;

        /**
        * boolean value, if the results should be returned as triples.
        *
        * @var          boolean
        * @access       private
        */
        var $returnAsTriples;
        
        /**
    * Constructor.
    *
    * @param dataset
        * @access       public
    */
        function IteratorFindQuadsDb(&$dbResultSet,&$datasetDb,$returnAsTriples=false)
        {
                $this->dbResultSet=& $dbResultSet;
                $this->datasetDb=& $datasetDb;
                $this->returnAsTriples=$returnAsTriples;
        }
        
        /**
    * Resets iterator list to start.
    *
        * @access public
    */
        function rewind()
        {
                //not supported
        }
        
        /**
    * Says if there are additional items left in the list.
    *
    * @return   boolean
        * @access       public
    */
        function valid()
        {
                if (($this->dbResultSet ===false) OR ($this->dbResultSet->EOF) )
                        return false;
                
                return true;
        }
        
        /**
    * Moves Iterator to the next item in the list.
    *
        * @access       public
    */
        function next()
        {
                if ($this->dbResultSet!==false)
                        $this->dbResultSet->moveNext();
        }
        
        /**
    * Returns the current item.
    *
    * @return   mixed
        * @access       public
    */
        function &current()
        {
                if ($this->dbResultSet===false)
                        return null;
                // subject
                if ($this->dbResultSet->fields[5] == 'r')
                $sub = new Resource($this->dbResultSet->fields[0]);
                else
                $sub = new BlankNode($this->dbResultSet->fields[0]);

                // predicate
                $pred = new Resource($this->dbResultSet->fields[1]);

                // object
                if ($this->dbResultSet->fields[6] == 'r')
                $obj = new Resource($this->dbResultSet->fields[2]);
                elseif ($this->dbResultSet->fields[6] == 'b')
                $obj = new BlankNode($this->dbResultSet->fields[2]);
                else {
                        $obj = new Literal($this->dbResultSet->fields[2], $this->dbResultSet->fields[3]);
                        if ($this->dbResultSet->fields[4])
                        $obj->setDatatype($this->dbResultSet->fields[4]);
                }

                if($this->returnAsTriples)
                        return (new Statement($sub, $pred, $obj));

                return (new Quad(new Resource($this->dbResultSet->fields[7]),$sub,$pred,$obj));
        }
        
        /**
    * Returns the key of the current item.
    *
    * @return   integer
        * @access       public
    */
        function key()
        {
                return $this->dbResultSet->_currentRow;
        }
}
?>