source: Dev/trunk/classes/AnswerSetConnector.php @ 195

<?php

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

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

        /**
         * function get()
         * @param type $arguments : An array having one ore more of the following elements:
         * 'uid', 'survey', 'respondent', 'answers'.
         */
        public function get($arguments)
        {
                $this->load();

                //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 ;
                                ' . $this->createArguments($arguments) . '
                        }';
                //Query the model
                $results = $this->model->sparqlQuery($querystring);
                $answerSets = array();
                if(!empty($results))
                {
                        $this->db = new DatabaseInterface();
                        foreach($results as $result)
                        {
                                $survey = $result['?for_survey']->label;
                                $respondent = $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()
         * @param type $uid : the uid for which the answers should be retrieved.
         */
        private function getAnswers($uid)
        {
                $result = $this->model->findRegex("[(".$uid.")]", "[(given_answer)]", null);
                $iterator = $result->getStatementIterator();
                $answers = array();
                while($iterator->hasNext())
                {
                        $element = $iterator->next();
                        $answers[] = $element->getLabelObject();
                }
                return $answers;
        }

        /**
         * function set()
         * @param type $rToolObject : The ResearchToolObject to be saved.
         */
        public function set($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;

                $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();
                return true;
        }
}