source: Dev/trunk/rdfapi/resModel/ResIterator.php @ 12

<?php 
/**
* ----------------------------------------------------------------------------------
* Class: ResIterator
* ----------------------------------------------------------------------------------
*
* @package      resModel
*/


/**
* Implementation of a resource iterator.
*
* This Iterator should be used in a for-loop like:
* $it = $ontClass->listInstances();
* for ($it->rewind(); $it->valid(); $it->next())
* {
*       $currentResource=$it->current();
* };
*
*
* @version  $Id: ResIterator.php 522 2007-08-14 09:22:22Z cweiske $
* @author Daniel Westphal <mail at d-westphal dot de>
*
*
* @package      resModel
* @access       public
**/
class ResIterator
{
        /**
        * Holds a reference to the assoiated ResModel / OntModel
        * @var          object Model
        * @access       private
        */
        var $associatedModel;
        
        /**
        * The current position
        * @var          integer
        * @access       private
        */
        var $key;
        
        /**
        * If the current resource is valid
        * @var          boolean
        * @access       private
        */
        var $valid;
        
        /**
        * The current resource
        * @var obejct ResResource
        * @access       private
        */
        var $currentResource;
        
        /**
        * The subject to search for.
        * @var          object ResResource
        * @access       private
        */
        var $searchSubject;
        
        /**
        * The predicate to search for.
        * @var          object ResResource
        * @access       private
        */
        var $searchPredicate;
        
        /**
        * The object to search for.
        * @var          object ResResource
        * @access       private
        */
        var $searchObject;
        
        /**
        * If the resource, we're intrested in is the subject (s), predicate(p), 
        * or object (o) of the found statements
        * 
        * @var          string
        * @access       private
        */
        var $getSPO;
        
        /**
        * Defines the type of resource, we'd like to receive.
        * 
        * @var          string
        * @access       private
        */
        var $returnType;
        
        /**
        * If set, each resource will first be checked, if it's
        * language fits.
        * 
        * @var          string
        * @access       private
        */
        var $findLiteralWithLang;
        
        
        /**
    * Constructor.
    *
        * $subject, $predicate, and $object are used like inf find().
        * $getSPO supports the strings 's', 'p', and 'o' to return
        * either the subject, predicate, or object of the result statements.
        * $returnType supports the strings 'ResProperty', 'ResLiteral',
        * 'OntProperty', 'OntClass', and 'Individual' and returns the resources
        * as the matching type.
    *
    * @param object ResResource  $subject
    * @param object ResResource  $predicate
    * @param object ResResource  $object
    * @param string                              $getSPO
    * @param object ResModel     $associatedModel
    * @param string                              $returnType
        * @access       public
    */
        function ResIterator($subject,$predicate,$object,$getSPO,& $associatedModel,$returnType = false)
        {
                $this->searchSubject =& $subject;
                $this->searchPredicate =& $predicate;
                $this->searchObject =& $object;
                $this->getSPO = $getSPO;
                $this->returnType = $returnType;
                $this->associatedModel =& $associatedModel;
                $this->findLiteralWithLang = false;
        }
        
        /**
    * Resets iterator list to start
    *
        * @access       public
    */
        function rewind()
        {
                $this->key = -1;
                $this->next();
        }
        
        /**
    * Says if there are additional items left in the list
    *
    * @return   boolean
        * @access       public
    */
        function valid()
        {
                return $this->valid;
        }
        
        /**
    * Moves Iterator to the next item in the list
    *
        * @access       public
    */
        function next()
        {
                $this->key++;
                $this->valid=($this->_getNextResource());
        }
        
        /**
    * Returns the current item
    *
    * @return   mixed
        * @access       public
    */
        function current()
        {
                return $this->currentResource;
        }
        
        /**
    * Returns the next Resource (subject, predicate, 
    * or object of the next matching statement).
    *
    * @return   object resResource
        * @access       private
    */
        function _getNextResource()
        {
                if ($this->findLiteralWithLang)
                { 
                        do 
                        {
                                $nextStatement = $this->associatedModel->findFirstMatchingStatement($this->searchSubject,$this->searchPredicate,$this->searchObject,$this->key);
                                if ($nextStatement === null)
                                        return false;
                                        
                                $object = $nextStatement->getObject();
                                if ($object->getLanguage() != $this->findLiteralWithLang)
                                {
                                        $hasCorrectLanguage=false;
                                        $this->key++;
                                } else 
                                {
                                        $hasCorrectLanguage=true;
                                }
                                        
                        } while (!$hasCorrectLanguage);
                } else 
                {
                        $nextStatement = $this->associatedModel->findFirstMatchingStatement($this->searchSubject,$this->searchPredicate,$this->searchObject,$this->key);
                }
                if ($nextStatement === null)
                        return false;
                
                switch ($this->getSPO) 
                {
                        case 's':
                                 $this->currentResource = $this->_getResourceAs($nextStatement->getSubject());
                                break;

                        case 'p':
                                 $this->currentResource = $this->_getResourceAs($nextStatement->getPredicate());
                                break;
                                
                        case 'o':
                                 $this->currentResource = $this->_getResourceAs($nextStatement->getObject());
                                break;
                }
                return (true);
        }
        
        /**
    * Returns the key of the current item
    *
    * @return   integer
        * @access       public
    */
        function key()
        {
                return $this->key;
        }
        
        /**
    * Sets that only Literals with the matching 
    * language should be returned
    *
    * @param    string
        * @access       public
    */
        function setFindLiteralWithLang($language)
        {
                $this->findLiteralWithLang = $language;
        }
        
        /**
    * Returns the $resource as an instance of the type
    * specified in $this->returnType.
    *
    * @param    object ResResource
    * @return   object ResResource
        * @access       private
    */
        function _getResourceAs($resource)
        {
                if ($this->findLiteralWithLang && $resource->getLanguage() != $this->findLiteralWithLang)
                        $this->_getNextResource();

                if($this->returnType)   
                        switch ($this->returnType) {
                
                                case 'ResProperty':
                                                return $this->associatedModel->createProperty($resource->getLabel());
                                        break;
                                        
                                case 'ResLiteral':
                                                $newLiteral = $this->associatedModel->createLiteral($resource->getLabel(),$resource->getLanguage());
                                                $newLiteral->setDatatype($resource->getDatatype());
                                                return $newLiteral;
                                        break;
                                        
                                case 'OntProperty':

                                                return $this->associatedModel->createOntProperty($resource->getLabel());
                                        break;
                                        
                                case 'OntClass':
                                                return $this->associatedModel->createOntClass($resource->getLabel());
                                        break;
                                        
                                case 'Individual':
                                        return $this->associatedModel->createIndividual($resource->getLabel());
                                break;
                        }
                return $resource;
        }
}

?>