source: Dev/trunk/classes/SessionConnector.php @ 198

<?php
// Survey database interface class as intermediate for storing data from the site to the RDF database 
require_once 'rdfConstants.php';
// Include RAP Library to write RDF files
include(RDFAPI_INCLUDE_DIR . "RDFAPI.php");

/**
 * Description of SessionConnector
 *
 * @author jkraaijeveld
 */
class SessionConnector extends Connector  
{
        protected $db;

        /**
         * Constructor for the SessionConnector
         */
        public function __construct()
        {
                $this->fileName = 'data/sessions/sessions.rdf';
                //Ensure the required folder for this connector exists
                if(!is_dir('data/sessions'))
                        mkdir('data/sessions');
        }

        /**
         * function get()
         * @param type $arguments : An array containing one or more of the following elements:
         * 'uid', 'title', 'creationdate', 'applications', 'surveys'
         */
        public function get($arguments)
        {
                $this->load();
        
                //Build the query string
                $querystring = '
                        PREFIX predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE . '>
                        PREFIX resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE . '>
                        SELECT DISTINCT ?uid, ?title, ?creator, ?creationdate
                        WHERE
                        {
                                _session predicates:resource_type resources:session ;
                                predicates:uid ?uid ;
                                predicates:title ?title ;
                                predicates:creator ?creator ;
                                predicates:creationdate ?creationdate ;
                                ' . $this->createArguments($arguments) . '
                        }';
                //Query the model
                $results = $this->model->sparqlQuery($querystring);
                $sessions = array();
                if(!empty($results))
                {
                        $this->db = new DatabaseInterface();
                        foreach($results as $result)
                        {
                                //Create a session object out of every result, get all required fields as well.
                                $pipeline = $this->getPipeline($result['?uid']->label);
                                $creator = $result['?creator']->label;
                                $datetime = new DateTime();
                                $datetime->setTimestamp(intval($result['?creationdate']->label));
                                $sessions[] = new Session($result['?uid']->label, $result['?title']->label, $creator, $datetime, $pipeline);
                        }
                }
                return $sessions;
        }
        /**
         * function getPipeline()
         * param type $uid : The Session uid for which the pipeline should be retrieved.
         */
        private function getPipeline($uid)
        {
                $result = $this->model->findRegex("[(".$uid.")]", "[(has_application)|(has_survey)]" ,null);
                $iterator = $result->getStatementIterator();
                $pipeline = array();
                while($iterator->hasNext())
                {
                        $element = $iterator->next();
                        $pipeline[] = $element->getLabelObject();
                }
                return $pipeline;
        }

        /**
         * function getAnswerSets()
         * @param type $uid : The Session uid for which the answerSets should be retrieved.
         */
        private function getAnswerSets($uid)
        {
                $result = $this->model->findRegex("[(".$uid.")]", "[(has_answerset)]" ,null);
                $iterator = $result->getStatementIterator();
                $answersets = array();
                while($iterator->hasNext())
                {
                        $element = $iterator->next();
                        $answersets[] = $element->getLabelObject();
                }
                return $answersets;
        }

        /**
         * function set()
         * @param type $rToolObjects : The ResearchToolObject to be saved.
         */
        public function set($rToolObject)
        {
                $this->load();
                //If evaluation fails, some references are incorrect.
                //We shouldn't save in this case. Instead - let the user know. This function returns false if the evaluation has failed.
                //TODO: Decide how to fix invalid references graciously.
                if(!$rToolObject->evaluate()) 
                        return false;

                $resourceSession = new Resource(SESSION . '/' . $rToolObject->uid);
                //Remove the old value stored with the given id
                $this->model->subtract($this->model->find($resourceSession, null, null));

                //Set the new values
                $resourceSessionType = new Resource(SESSION);
                $predicateType = new Resource(RTYPE);
                $this->model->add(new Statement($resourceSession, $predicateType, $resourceSessionType));

                $sessionId = new Literal($rToolObject->uid);
                $predicateId = new Resource(UID);
                $this->model->add(new Statement($resourceSession, $predicateId, $sessionId));

                $sessionTitle = new Literal($rToolObject->title);
                $predicateTitle = new Resource(TITLE);
                $this->model->add(new Statement($resourceSession, $predicateTitle, $sessionTitle));

                $sessionCreator = new Literal($rToolObject->creator->uid);
                $predicateCreator = new Resource(CREATOR);
                $this->model->add(new Statement($resourceSession, $predicateCreator, $sessionCreator));

                $sessionTimestamp = new Literal($rToolObject->datetime->getTimestamp());
        //      $sessionTimestamp = new Literal($rToolObject->datetime);    // Edit of above function, allows for creation of session, but still results in errors...
        $predicateTimestamp = new Resource(DATETIME);
                $this->model->add(new Statement($resourceSession, $predicateTimestamp, $sessionTimestamp));

                //Create a sequence to store the different applications and surveys.
                if(isset($rToolObject->pipeline))
                {
                        foreach($rToolObject->pipeline as $element)
                        {
                                $sessionObject = new Literal($element->uid);
                                $predicateObject = null;
                                if(get_class($element) == "Application")
                                        $predicateObject = new Resource(HAS_APPLICATION);
                                else if(get_class($element) == "Survey")
                                        $predicateObject = new Resource(HAS_SURVEY);
                                if(isset($predicateObject))
                                        $this->model->add(new Statement($resourceSession, $predicateObject, $sessionObject));
                        }
                }

                if(isset($rToolObject->answersets))
                {
                        foreach($rToolObject->answersets as $answerset)
                        {
                                $sessionAnswerSet = new Literal($answerset->uid);
                                $predicateAnswerSet = new Resource(HAS_ANSWERSET);
                                $this->model->add(new Statement($resourceSession, $predicateAnswerSet, $sessionAnswerSet));
                        }
                }

                $this->save();
                return true;
        }
}
?>