source: Dev/trunk/classes/AnswerConnector.php @ 188

<?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 AnswerConnector
 *
 * @author jkraaijeveld
 */
class AnswerConnector extends Connector{
    
    /**
     * Constructor for AnswerConnector
     */
    public function __construct() {
        //Ensure the required folder for this connector exists
        if (!is_dir('data/answers/'))
                        mkdir('data/answers/');
                $this->fileName = 'data/answers/answers.rdf';
    }
    
        /**
         * function get()
         * @param type $arguments: An array having one or more of the following elements:
         * 'uid', 'question', 'values'.
         */
    public function get($arguments)
        {
                $this->load();
                //Create the querystring
                $querystring = '
                        PREFIX predicates: <' . SURVEYTOOL_PREDICATES_NAMESPACE . '>
                        PREFIX resources: <' . SURVEYTOOL_RESOURCES_NAMESPACE . '>
                        SELECT DISTINCT ?uid, ?question_code
                        WHERE
                        {
                                _answer predicates:resource_type resources:answer;

                                predicates:uid ?uid ;
                                predicates:question_code ?question_code ;
                                ' . $this->createArguments($arguments) . '
                        }';

                //Query the model
                $results = $this->model->sparqlQuery($querystring);     
                //An answer can have multiple values, get all these values for the answer instances found.
                $answers = array();
                if(!empty($results))
                {
                        foreach($results as $result)
                        {
                                $answers[] = new Answer($result['?uid']->label, $result['?question_code']->label, $this->getValues($result['?uid']->label));
                        }
                }
                return $answers;
        }

        /**
         * function getValues()
         * @param type $uid : The uid of the Answer for which the values should be gotten.
         */
        private function getValues($uid)
        {
                $result = $this->model->findRegex("[(".$uid.")]", "[(answered)]", null);
                $iterator = $result->getStatementIterator();
                $values = array();
                while($iterator->hasNext())
                {
                        $element = $iterator->next();
                        $values[] = $element->getLabelObject();
                }
                return $values;
        } 

    /**
         * 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;
        $resourceAnswer = new Resource(ANSWER.'/'.$rToolObject->uid);        
        //Remove the old value stored with the given id
        $this->model->subtract($this->model->find($resourceAnswer, null, null));
        
        //Save all the new values
        $resourceAnswerType = new Resource(ANSWER);
        $predicateRType = new Resource(RTYPE);
        $this->model->add(new Statement($resourceAnswer,$predicateRType,$resourceAnswerType));
        
                $answerId = new Literal($rToolObject->uid);
                $predicateId = new Resource(UID);
                $this->model->add(new Statement($resourceAnswer, $predicateId, $answerId));

                $questionId = new Literal($rToolObject->question->uid);
                $predicateQId = new Resource(QCODE);
                $this->model->add(new Statement($resourceAnswer, $predicateQId, $questionId));

                if(isset($rToolObject->values))
                {
                        foreach($rToolObject->values as $value)
                        {
                                $answerValue = new Literal($value);
                                $predicateAnswer = new Resource(ANSWERED);
                                $this->model->add(new Statement($resourceAnswer, $predicateAnswer, $answerValue));
                        }
                }
                $this->save();
                return true;
    }
}

?>