source: Dev/trunk/rdfapi/rdql/RdqlResultIterator.php @ 12

<?php

// ----------------------------------------------------------------------------------
// Class: RdqlResultIterator
// ----------------------------------------------------------------------------------

/**
 * Iterator for traversing Rdql results. 
 * This class can be used for iterating forward and backward trough Rdql results.
 * It should be instanced using the rdqlQueryAsIterator() method of a MemModel or a DBModel.
 * 
 * @version  $Id: RdqlResultIterator.php 268 2006-05-15 05:28:09Z tgauss $
 * @author Daniel Westphal <mail@d-westphal.de>, Chris Bizer <chris@bizer.de>
 *
 * @package rdql
 * @access      public
 *
 */ 
 class RdqlResultIterator extends Object {

        /**
        * Reference to the Rdql result
        * @var          array RdqlResult
        * @access       private
        */      
    var $RdqlResult;

        /**
        * Current position
        * RdqlResultIterator does not use the build in PHP array iterator,
        * so you can use serveral iterators on a single Rdql result.
        * @var          integer
        * @access       private
        */      
    var $position;
   
  
   /**
    * Constructor
    *
    * @param    object RdqlResult
        * @access       public
    */
    function RdqlResultIterator(&$RdqlResult) {
        
        $noResult = TRUE;
        foreach($RdqlResult[0] as $value) 
                if ($value != NULL) {
                        $noResult = FALSE;
                        break;
                }       
                
        if($noResult)           
                $this->RdqlResult = NULL;
        else 
                $this->RdqlResult = $RdqlResult;        

                $this->position = -1;
        }
 
  /**
   * Returns the labels of the result as array.
   * @return    array of strings with the result labels OR null if there are no results.
   * @access    public  
   */
  function getResultLabels() {
                if(count($this->RdqlResult)>0) {
                        return array_keys($this->RdqlResult[0]);
                } else return null;
   }

   /**
   * Returns the number of results.
   * @return    integer
   * @access    public  
   */
  function countResults() {
                
                        return count($this->RdqlResult);

   }
  /**
   * Returns TRUE if there are more results.
   * @return    boolean
   * @access    public  
   */
  function hasNext() {
                if ($this->position < count($this->RdqlResult) - 1 ) {                  
                        return TRUE;
                } else {
                        return FALSE;
                }
   }

  /**
   * Returns TRUE if the first result has not been reached.
   * @return    boolean
   * @access    public  
   */
  function hasPrevious() {
                if ($this->position > 0) {
                        return TRUE;
                } else {
                        return FALSE;
                }   }   
   
  /**
   * Returns the next result array.
   * @param     integer $element        
   * @return    result array OR single result if $element was specified OR NULL if there is no next result.
   * @access    public  
   */
  function next($element = null) {
                if ($this->position < count($this->RdqlResult) - 1) {
                        $this->position++;
                        if ($element) {return $this->RdqlResult[$this->position][$element];}
                                else return $this->RdqlResult[$this->position];
                } else {
                        return NULL;
                }
   }

  /**
   * Returns the previous result.
   * @param     integer $element        
   * @return    result array OR single result if $element was specified OR NULL if there is no next result.
   * @access    public  
   */
  function previous($element = null) {
        if ($this->position > 0) {
                        $this->position--;
                        if ($element) {return $this->RdqlResult[$this->position][$element];}
                                else return $this->RdqlResult[$this->position];
                } else {
                        return NULL;
                }   
  }

  /**
   * Returns the current result.
   * @param     integer $element        
   * @return    result array OR single result if $element was specified OR NULL if there is no next result.
   * @access    public  
   */
  function current($element = null) {
                if (($this->position >= 0) && ($this->position < count($this->RdqlResult))) {
                        if ($element) {return $this->RdqlResult[$this->position][$element];}
                                else return $this->RdqlResult[$this->position];
                } else {
                        return NULL;
                } 
   }
   
  /**
   * Moves the pointer to the first result.
   * @return    void
   * @access    public  
   */
  function moveFirst() {
                        $this->position = 0;
   }

  /**
   * Moves the pointer to the last result.
   * @return    void
   * @access    public  
   */
  function moveLast() {
                        $this->position = count($this->RdqlResult) - 1;
   }
   
     /**
   * Moves the pointer to a specific result.
   * If you set an off-bounds value, next(), previous() and current() will return NULL
   * @return    void
   * @access    public  
   */
  function moveTo($position) {
                        $this->position = $position;
   }
   
     /**
   * Returns the current position of the iterator.
   * @return    integer
   * @access    public  
   */
  function getCurrentPosition() {
                        return $this->position;
   }
  
} 

?>