Source for file IteratorFindQuadsMem.php

Documentation is available at IteratorFindQuadsMem.php

  1. <?php
  2. require_once RDFAPI_INCLUDE_DIR . 'dataset/Quad.php';
  3. // ----------------------------------------------------------------------------------
  4. // Class: IteratorFindQuadsMem
  5. // ----------------------------------------------------------------------------------
  6.  
  7.  
  8.  
  9. /**
  10. * Implementation of a quad iterator.
  11. *
  12. * This Iterator should be used like:
  13. * for($iterator = $dataset->findInNamedGraphs(null,null,null,null); $iterator->valid(); $iterator->next())
  14. * {
  15. *    $currentQuad=$it->current();
  16. * };
  17. *
  18. * @version  $Id: fsource_dataset__datasetIteratorFindQuadsMem.php.html 442 2007-06-01 16:19:26Z cax $
  19. * @author Daniel Westphal (http://d-westphal.de)
  20. *
  21. *
  22. * @package     dataset
  23. * @access    public
  24. ***/
  25. class IteratorFindQuadsMem
  26. {
  27.     /**
  28.     * key value in the current graph.
  29.     *
  30.     * @var     dataset 
  31.     * @access    private
  32.     */
  33.     var $graphKey;
  34.  
  35.     /**
  36.     * boolean value, if the results should be returned as triples.
  37.     *
  38.     * @var        boolean 
  39.     * @access    private
  40.     */
  41.     var $returnAsTriples;
  42.  
  43.     /**
  44.     * The current position.
  45.     *
  46.     * @var        integer 
  47.     * @access    private
  48.     */
  49.     var $key;
  50.  
  51.     /**
  52.     * If the current resource is valid.
  53.     *
  54.     * @var        boolean 
  55.     * @access    private
  56.     */
  57.     var $valid;
  58.  
  59.     /**
  60.     * The current NamedGraph.
  61.     *
  62.     * @var  NamedGraph 
  63.     * @access    private
  64.     */
  65.     var $current;
  66.  
  67.     /**
  68.     * The graphName Resource to search for.
  69.     *
  70.     * @var string 
  71.     * @access    private
  72.     */
  73.     var $findGraphName;
  74.  
  75.     /**
  76.     * The subject Resource to search for.
  77.     *
  78.     * @var string 
  79.     * @access    private
  80.     */
  81.     var $findSubject;
  82.  
  83.     /**
  84.     * The predicate Resource to search for.
  85.     *
  86.     * @var string 
  87.     * @access    private
  88.     */
  89.     var $findPredicate;
  90.  
  91.     /**
  92.     * The object Resource to search for.
  93.     *
  94.     * @var string 
  95.     * @access    private
  96.     */
  97.     var $findObject;
  98.  
  99.     /**
  100.     * Iterator over all graphs of the RDF dataset.
  101.     *
  102.     * @var string 
  103.     * @access    private
  104.     */
  105.     var $graphIterator;
  106.  
  107.  
  108.     /**
  109.     * Constructor.
  110.     *
  111.     * $subject, $predicate, and $object are used like find().
  112.     * $getSPO supports the strings 's', 'p', and 'o' to return
  113.     * either the subject, predicate, or object of the result statements.
  114.     *
  115.     *
  116.     * @param Resource 
  117.     * @param Resource 
  118.     * @param Resource 
  119.     * @param dataset 
  120.     * @param Boolean 
  121.     * @access    public
  122.     */
  123.     function IteratorFindQuadsMem($subject,$predicate,$object,&$graphIterator, $returnAsTriples=false)
  124.     {
  125.         $this->findSubject=$subject;
  126.         $this->findPredicate=$predicate;
  127.         $this->findObject=$object;
  128.         $this->graphIterator=&$graphIterator;
  129.         $this->rewind();
  130.         $this->returnAsTriples=$returnAsTriples;
  131.     }
  132.  
  133.     /**
  134.     * Resets iterator list to start.
  135.     *
  136.     * @access    public
  137.     */
  138.     function rewind()
  139.     {
  140.         $this->graphIterator->rewind();
  141.         $this->key = -1;
  142.         $this->graphKey=-1;
  143.         $this->next();
  144.     }
  145.  
  146.     /**
  147.     * Says if there are additional items left in the list.
  148.     *
  149.     * @return    boolean 
  150.     * @access    public
  151.     */
  152.     function valid()
  153.     {
  154.         return $this->valid;
  155.     }
  156.  
  157.     /**
  158.     * Moves Iterator to the next item in the list.
  159.     *
  160.     * @access    public
  161.     */
  162.     function next()
  163.     {
  164.         if($this->graphIterator->valid()===false)
  165.         {
  166.             $this->valid=false;
  167.             return;
  168.         }
  169.  
  170.         $currentGraph=&$this->graphIterator->current();
  171.         $this->current= $currentGraph->findFirstMatchingStatement($this->findSubject,$this->findPredicate,$this->findObject,++$this->graphKey);
  172.         if($this->current==null)
  173.         {
  174.             do
  175.             {
  176.                 $this->graphIterator->next();
  177.                 if($this->graphIterator->valid()===false)
  178.                 {
  179.                     $this->valid=false;
  180.                     return;
  181.                 }
  182.                 $currentGraph=&$this->graphIterator->current();
  183.                 $this->graphKey=-1;
  184.                 $this->current= $currentGraph->findFirstMatchingStatement($this->findSubject,$this->findPredicate,$this->findObject,++$this->graphKey);
  185.  
  186.             } while ($this->current==null);
  187.         }
  188.         $this->key++;
  189.         $this->valid=true;
  190.     }
  191.  
  192.     /**
  193.     * Returns the current item.
  194.     *
  195.     * @return    mixed 
  196.     * @access    public
  197.     */
  198.     function current()
  199.     {
  200.         if($this->returnAsTriples) return $this->current;
  201.  
  202.         $currentGraph=&$this->graphIterator->current();
  203.         return new Quad(new Resource($currentGraph->getGraphName()),$this->current->getSubject(),$this->current->getPredicate(),$this->current->getObject());
  204.     }
  205.  
  206.     /**
  207.     * Returns the key of the current item.
  208.     *
  209.     * @return    integer 
  210.     * @access    public
  211.     */
  212.     function key()
  213.     {
  214.         return $this->key;
  215.     }
  216. }
  217. ?>

Documentation generated on Fri, 1 Jun 2007 16:49:37 +0200 by phpDocumentor 1.3.2