source: Dev/trunk/classes/AnswerSetConnector.php @ 156

<?php

/**
 * Description of AnswerSetConnector
 *
 * @author jkraaijeveld
 */
class AnswerSetConnector implements IConnector{
    protected $model;
    protected $fileName = 'data/answers/answersets.rdf';
    protected $db;

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

        /**
         * function load()
         * Loads the file into the standard MemModel
         */
        public function load()
        {
            //Get the Memory Model from the ModelFactory
        $this->model = ModelFactory::getDefaultModel();
        
        //Ensure the required file exists before loading
        if(file_exists($this->fileName))
            $this->model->load($this->fileName);
        }

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

        /**
         * Get the AnswerSets corresponding to the arguments
         * Arguments can be one or more of the following:
         * uid, survey, respondent, answers
         * Where answers is an array of answer ids
         */
        public function get($arguments)
        {
                $this->load();
                
                $keys = array_keys($arguments);
                $uid = ""; $survey = ""; $respondent = ""; $answers = "";
                if(in_array("uid", $keys))
                        $uid = 'predicates:uid \''.$arguments["uid"].'\' ';
                if(in_array("survey", $keys))
                        $survey = 'predicates:for_survey \''.$arguments["survey"].'\' ';
                if(in_array("respondent", $keys))
                        $respondent = 'predicates:by_respondent \''.$arguments["respondent"].'\' ';
                if(in_array("answers", $keys))
                {
                        foreach ($arguments["answers"] as $answer)
                        {
                                $answers = $answers . 'predicates:given_answer \'' . $answer . '\' ';
                        }
                }

                //Build the query string
                $querystring = '
                        PREFIX predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE . '>
                        PREFIX resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE . '>
                        SELECT DISTINCT ?uid, ?for_survey, ?by_respondent
                        WHERE
                        {
                                _answerset      predicates:resource_type        resources:answerset ;
                                predicates:uid ?uid ;
                                predicates:for_survey ?for_survey ;
                                predicates:by_respondent ?by_respondent ;
                                ' . $uid . $survey . $respondent . $answers . '
                        }';

                //Query the model
                $results = $this->model->sparqlQuery($querystring);
                $answerSets = array();
                if(!empty($results))
                {
                        $this->db = new DatabaseInterface();
                        foreach($results as $result)
                        {
                                $survey = $this->db->get("survey", array("uid" => $result['?for_survey']->label));
                                $respondent = $this->db->get("respondent", array("uid" => $result['?by_respondent']->label));
                                $answers =      $this->getAnswers($result['?uid']->label);
                                $answerSets[] = new AnswerSet($result['?uid']->label, $survey[0], $respondent[0], $answers);
                        }
                }
                return $answerSets;
        }

        /**
         * function getAnswers()
         * Gets the answers corresponding to the given answerset uid
         */
        private function getAnswers($uid)
        {
                $querystring = '
                        PREFIX predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE .'>
                        PREFIX resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE .'>
                        SELECT DISTINCT ?given_answer
                        WHERE
                        {
                                _answerset predicates:resource_type resources:answerset ;
                                predicates:given_answer ?given_answer ;
                                predicates:uid \'' . $uid . '\'
                        }';
                $answers = $this->model->sparqlQuery($querystring);
                $returnArray = array();
                if(!empty($answers))
                {
                        foreach($answers as $answer)
                        {
                                $answerR = $this->db->get("answer", array("uid" => $answer["?given_answer"]->label));
                                $returnArray[] = $answerR[0];
                        }
                }
                return $returnArray;
        }

        /**
         * Save the given AnswerSet in the file.
         * @param type $rToolObject
         */
        public function set($rToolObject)
        {
                $this->load();
                $resourceAnswerSet = new Resource(ANSWERSET . '/' . $rToolObject->uid);
                //Remove the old value stored with the given id
                $this->model->subtract($this->model->find($resourceAnswerSet, null, null));

                //Set the new values
                $resourceAnswerSetType = new Resource(ANSWERSET);
                $predicateRType = new Resource(RTYPE);
                $this->model->add(new Statement($resourceAnswerSet, $predicateRType, $resourceAnswerSetType));

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

                $surveyId = new Literal($rToolObject->survey->uid);
                $predicateSurvey = new Resource(FOR_SURVEY);
                $this->model->add(new Statement($resourceAnswerSet, $predicateSurvey, $surveyId));

                $respondentId = new Literal($rToolObject->respondent->uid);
                $predicateRespondent = new Resource(BY_RESPONDENT);
                $this->model->add(new Statement($resourceAnswerSet, $predicateRespondent, $respondentId));
                
                if(isset($rToolObject->answers))
                {
                        foreach($rToolObject->answers as $answer)
                        {
                                $answerId = new Literal($answer->uid);
                                $predicateAnswer = new Resource(GIVEN_ANSWER);
                                $this->model->add(new Statement($resourceAnswerSet, $predicateAnswer, $answerId));
                        }
                }
                $this->save();
        }
}