source: Dev/branches/jos-branch/classes/SessionConnector.php @ 148

<?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 implements IConnector
{
        protected $model;
        protected $fileName = 'data/sessions/sessions.rdf';
        protected $db;

        /**
         * Constructor for the SessionConnector
         */
        public function __construct()
        {
                //Ensure the required folder for this connector exists
                if(!is_dir('data/sessions'))
                        mkdir('data/sessions');
        }

        /**
         * function load()
         * Loads the file into the standard MemModel
         */
        public function load()
        {
                $this->model = ModelFactory::getDefaultModel();
                if(file_exists($this->fileName))
                        $this->model->load($this->fileName);
        }

        /**
         * fucntion save()
         * Saves the MemModel into the given file.
         */
        public function save()
        {
                $this->model->saveAs($this->fileName,'rdf');
        }

        /**
         * Get the Sessions corresponding to the arguments
         * @ param type $arguments
         * Arguments can be one or more of the following:
         * uid, title, datetime, applications, surveys, answersets
         * Where applications, surveys and answersets are arrays containing ids
         */
        public function get($arguments)
        {
                $this->load();

                $keys = array_keys($arguments);
                $uid = ""; $title = ""; $datetime = ""; $applications = ""; $surveys = ""; $answersets = "";
                if(in_array("uid", $keys))
                        $uid = 'predicates:uid \''.$arguements["uid"].'\' ';
                if(in_array("title", $keys))
                        $title = 'predicates:title \''.$arguments["title"].'\' ';
                if(in_array("datetime", $keys))
                        $datetime = 'predicates:datetime \''.$arguments["datetime"].'\' ';
                if(in_array("applications", $keys))
                {
                        foreach($arguments["applications"] as $application)
                        {
                                $applications = $applications . 'predicates:has_application \'' . $application . '\' ';
                        }
                }
                if(in_array("surveys", $keys))
                {
                        foreach($arguments["surveys"] as $survey)
                        {
                                $surveys = $surveys . 'predicates:has_survey \'' . $survey . '\' ';
                        }
                }
                if(in_array("answersets", $keys))
                {
                        foreach($arguments["answersets"] as $answerset)
                        {
                                $answersets = $answersets . 'predicates:has_answerset \'' . $answerset . '\' ';
                        }
                }
        
                //Build the query string
                $querystring = '
                        PREFIX predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE . '>
                        PREFIX resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE . '>
                        SELECT DISTINCT ?uid, ?title, ?datetime
                        WHERE
                        {
                                _session predicates:resource_type resources:session ;
                                predicates:uid ?uid ;
                                predicates:title ?title ;
                                ' . $uid . $title . $datetime . $applications . $surveys . $answersets . '
                        }';
                //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);
                                $answersets = $this->getAnswerSets($result['?uid']->label);
                                $datetime = new DateTime();
                                $datetime->setTimestamp(intval($result['?datetime']));
                                $sessions[] = new Session($result['?uid']->label, $result['?title']->label, $datetime, $pipeline, $answersets);
                        }
                }
                return $sessions;
        }
        /**
         * function getPipeline
         * Get the application and survey objects of the Session in order
         */
        private function getPipeline($uid)
        {
                $result = $this->model->findRegex("[(".$uid.")]", "[(has_application)|(has_survey)]" ,null);
                $iterator = $result->getStatementIterator();
                $pipeline = array();
                while($iterator->hasNext())
                {
                        $element = $iterator->next();
                        if(strpos($element->getLabelPredicate(), "has_application") != false)
                        {
                                $applications = $this->db->get("application", array("uid" => $element->getLabelObject()));
                                $pipeline[] = $applications[0];
                        }
                        else
                        {
                                $surveys = $this->db->get("survey", array("uid" => $element->getLabelObject()));
                                $pipeline[] = $surveys[0];
                        }
                }
                return $pipeline;
        }

        /**
         * function getAnswerSets
         * Get the answersets belonging to the given session
         */
        private function getAnswerSets($uid)
        {
                $result = $this->model->findRegex("[(".$uid.")]", "[(has_answerset)]" ,null);
                $iterator = $result->getStatementIterator();
                $answersets = array();
                while($iterator->hasNext())
                {
                        $element = $iterator->next();
                        $resultsets = $this->db->get("answerset", array("uid" => $element->getLabelObject()));
                        $answersets[] = $resultsets[0];
                }
                return $answersets;
        }

        /**
         * Save the given Session object in the file.
         * @param type $rToolObjects
         */
        public function set($rToolObject)
        {
                $this->load();
                $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));

                $sessionTimestamp = new Literal($rToolObject->datetime->getTimestamp());
                $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();
        }
}
?>