diff --git a/backend/lib/View/JSON.php b/backend/lib/View/JSON.php
index 1982818..241cd19 100644
--- a/backend/lib/View/JSON.php
+++ b/backend/lib/View/JSON.php
@@ -23,6 +23,8 @@
 
 namespace Volkszaehler\View;
 
+use Volkszaehler\Interpreter;
+
 use Volkszaehler\View\HTTP;
 use Volkszaehler\Util;
 use Volkszaehler\Model;
@@ -57,22 +59,45 @@ class JSON extends View {
 		$this->setPadding($request->getParameter('padding'));
 	}
 
-	public function addChannel(Model\Channel $channel, array $data = NULL) {
-		$jsonChannel = self::convertEntity($channel);
-		$jsonChannel['type'] = $channel->getType();
+	/**
+	 * Process, encode and print output
+	 */
+	protected function render() {
+		$json = $this->json->encode((Util\Debug::isActivated()) ? JSON_PRETTY : 0);
 
-		if (isset($data)) {
-			$jsonChannel['data'] = self::convertData($data);
+		if ($this->padding) {
+			$json = 'if (self.' . $this->padding . ') { ' . $this->padding  . '(' . $json . '); }';
 		}
 
-		$this->json['channel'] = $jsonChannel;
+		$this->response->setHeader('Content-type', 'application/json');
+		echo $json;
 	}
 
-	public function addAggregator(Model\Aggregator $aggregator, $recursive = FALSE) {
+	/**
+	 * Add channel to output queue
+	 *
+	 * @param Model\Channel $channel
+	 */
+	protected function addChannel(Model\Channel $channel) {
+		$this->json['channel'] = self::convertEntity($channel);
+	}
+
+	/**
+	 * Add aggregator to output queue
+	 *
+	 * @param Model\Aggregator $aggregator
+	 * @param boolean $recursive
+	 */
+	protected function addAggregator(Model\Aggregator $aggregator, $recursive = FALSE) {
 		$this->json['group'] = self::convertAggregator($aggregator, $recursive);
 	}
 
-	public function addDebug(Util\Debug $debug) {
+	/**
+	 * Add debugging information include queries and messages to output queue
+	 *
+	 * @param Util\Debug $debug
+	 */
+	protected function addDebug(Util\Debug $debug) {
 		$this->json['debug'] = array(
 			'time' => $debug->getExecutionTime(),
 			'messages' => $debug->getMessages(),
@@ -83,6 +108,12 @@ class JSON extends View {
 		);
 	}
 
+	/**
+	 * Add exception to output queue
+	 *
+	 * @param \Exception $exception
+	 * @param boolean $debug
+	 */
 	protected function addException(\Exception $exception, $debug = FALSE) {
 		$exceptionInfo = array(
 			'type' => get_class($exception),
@@ -103,9 +134,26 @@ class JSON extends View {
 		}
 	}
 
+	/**
+	 * Add data to output queue
+	 *
+	 * @param Interpreter\InterpreterInterface $interpreter
+	 */
+	protected function addData(Interpreter\InterpreterInterface $interpreter) {
+		$this->json['data'][$interpreter->getUuid()] = $interpreter->getValues($this->request->getParameter('groupBy'));
+	}
+
+	/**
+	 * Converts entity to array for json_encode()
+	 *
+	 * @param Model\Entity $entity
+	 * @return array
+	 */
 	protected static function convertEntity(Model\Entity $entity) {
 		$jsonEntity = array();
 		$jsonEntity['uuid'] = (string) $entity->getUuid();
+		$jsonEntity['type'] = $entity->getType();
+
 
 		foreach ($entity->getProperties() as $key => $value) {
 			$jsonEntity[$key] = $value;
@@ -114,43 +162,27 @@ class JSON extends View {
 		return $jsonEntity;
 	}
 
-	protected static function convertAggregator(Model\Aggregator $aggregator, $recursive = FALSE) {
+	/**
+	 * Converts aggregator to array for json_encode
+	 *
+	 * @param Model\Aggregator $aggregator
+	 * @param boolean $recursive
+	 * @return array
+	 */
+	protected static function convertAggregator(Model\Aggregator $aggregator) {
 		$jsonAggregator = self::convertEntity($aggregator);
 
 		foreach ($aggregator->getChannels() as $channel) {
-			$jsonAggregator['channels'][] = (string) $channel->getUuid();
+			$jsonAggregator['channels'][] = self::convertEntity($channel);
 		}
 
-		if ($recursive) {
-			$jsonAggregator['groups'] = array();
-
-			foreach ($aggregator->getChildren() as $subAggregator) {
-				$jsonAggregator['groups'][] = $this->toJson($subAggregator, $recursive);	// recursion
-			}
+		foreach ($aggregator->getChildren() as $subAggregator) {
+			$jsonAggregator['groups'][] = self::convertAggregator($subAggregator);	// recursion
 		}
 
 		return $jsonAggregator;
 	}
 
-	protected static function convertData($data) {
-		array_walk($data, function(&$reading) {
-			$reading[1] = round($reading[1], View::PRECISSION);
-		});
-
-		return $data;
-	}
-
-	public function render() {
-		$json = $this->json->encode((Util\Debug::isActivated()) ? JSON_PRETTY : 0);
-
-		if ($this->padding) {
-			$json = 'if (self.' . $this->padding . ') { ' . $this->padding  . '(' . $json . '); }';
-		}
-
-		$this->response->setHeader('Content-type', 'application/json');
-		echo $json;
-	}
-
 	/*
 	 * Setter & getter
 	 */
diff --git a/backend/lib/View/JpGraph.php b/backend/lib/View/JpGraph.php
index 108dba9..3e51f45 100644
--- a/backend/lib/View/JpGraph.php
+++ b/backend/lib/View/JpGraph.php
@@ -23,6 +23,8 @@
 
 namespace Volkszaehler\View;
 
+use Volkszaehler\Interpreter;
+
 use Volkszaehler\Model;
 use Volkszaehler\Util;
 
@@ -39,6 +41,7 @@ require_once VZ_BACKEND_DIR . '/lib/vendor/JpGraph/jpgraph_date.php';
  * @author Steffen Vogel <info@steffenvogel.de>
  * @link http://jpgraph.net/
  * @todo add caching
+ * @todo rework
  */
 class JpGraph extends View {
 	/**
@@ -96,8 +99,10 @@ class JpGraph extends View {
 	 * @param $obj
 	 * @param $data
 	 */
-	public function addChannel(Model\Channel $channel, array $data = NULL){
-		if (isset($data) && count($data) > 0) {
+	public function addData(Interpreter\Interpreter $interpreter){
+		$data = $interpreter->getValues(800);
+
+		if (count($data) > 0) {
 			$count = count($this->channels);
 			$xData = $yData = array();
 
@@ -109,7 +114,7 @@ class JpGraph extends View {
 			// Create the scatter plot
 			$plot = new \ScatterPlot($yData, $xData);
 
-			$plot->setLegend($channel->getProperty('name')->getValue() . ': ' . $channel->getProperty('description')->getValue() . ' [' . $channel->getDefinition()->getUnit() . ']');
+			$plot->setLegend($interpreter->getChannel()->getProperty('title') . ':  [' . $interpreter->getChannel()->getDefinition()->getUnit() . ']');
 			$plot->SetLinkPoints(TRUE, self::$colors[$count]);
 
 			$plot->mark->SetColor(self::$colors[$count]);
@@ -117,7 +122,7 @@ class JpGraph extends View {
 			$plot->mark->SetType(MARK_DIAMOND);
 			$plot->mark->SetWidth(1);
 
-			$axis = $this->getAxisIndex($channel);
+			$axis = $this->getAxisIndex($interpreter->getChannel());
 			if ($axis >= 0) {
 				$this->graph->AddY($axis, $plot);
 			}
@@ -125,30 +130,25 @@ class JpGraph extends View {
 				$this->graph->Add($plot);
 			}
 
-			$this->channels[] = $channel;
-		}
-		else {
-			throw new \Exception('Can\'t plot channels without data!');
+			$this->channels[] = $interpreter->getChannel();
 		}
 	}
 
-	/**
-	 * adds all channel of group as new plots to the graph
-	 *
-	 * @param Model\Aggregator $aggregator
-	 */
+	public function addChannel(Model\Channel $channel) {
+		throw new \Exception(get_class($this) . ' cant show ' . get_class($channel));
+	}
+
 	public function addAggregator(Model\Aggregator $aggregator) {
-		foreach ($aggregator->getChannels() as $child) {
-			$this->addChannel($child);
-		}
+		throw new \Exception(get_class($this) . ' cant show ' . get_class($aggregator));
 	}
 
 	public function addDebug(Util\Debug $debug) {
-		throw new \Exception(get_class($this) . ' cant show debugging information');
+		throw new \Exception(get_class($this) . ' cant show ' . get_class($debug));
 	}
 
 	/**
-	 * shows exception
+	 * Shows exception
+	 *
 	 * @todo avoid graph plotting and set content-type to text/plain
 	 * @param \Exception $exception
 	 */
@@ -160,22 +160,22 @@ class JpGraph extends View {
 	 * check weather a axis for the indicator of $channel exists
 	 *
 	 * @param \Volkszaehler\Model\Channel $channel
-	 * @todo call getType() only once
 	 */
 	protected function getAxisIndex(\Volkszaehler\Model\Channel $channel) {
-		if (!in_array($channel->getType(), array_keys($this->axes))) {
-			$count =count($this->axes);
+		$type = $channel->getType();
+
+		if (!array_key_exists($type, $this->axes)) {
+			$count = count($this->axes);
 			if ($count == 0) {
-				$this->axes[$channel->getType()] = -1;
+				$this->axes[$type] = -1;
 
 				$yaxis = $this->graph->yaxis;
 			}
 			else {
-				$this->axes[$channel->getType()] = $count - 1;
+				$this->axes[$type] = $count - 1;
+				$this->graph->SetYScale($this->axes[$type],'lin');
 
-				$this->graph->SetYScale($this->axes[$channel->getType()],'lin');
-
-				$yaxis = $this->graph->ynaxis[$this->axes[$channel->getType()]];
+				$yaxis = $this->graph->ynaxis[$this->axes[$type]];
 			}
 
 			$yaxis->title->Set($channel->getDefinition()->getUnit());
@@ -186,7 +186,7 @@ class JpGraph extends View {
 			$yaxis->SetTitleMargin('50');
 		}
 
-		return $this->axes[$channel->getType()];
+		return $this->axes[$type];
 	}
 
 	/**
@@ -194,11 +194,11 @@ class JpGraph extends View {
 	 *
 	 * headers has been set automatically
 	 */
-	protected function renderResponse() {
+	protected function render() {
 		$this->graph->SetMargin(75, (count($this->axes) - 1) * 65 + 10, 20, 90);
 
 		// Display the graph
-		$this->graph->Stroke();
+		//$this->graph->Stroke();
 	}
 }
 
diff --git a/backend/lib/View/View.php b/backend/lib/View/View.php
index 26da2a5..524c088 100644
--- a/backend/lib/View/View.php
+++ b/backend/lib/View/View.php
@@ -23,6 +23,10 @@
 
 namespace Volkszaehler\View;
 
+use Volkszaehler\Interpreter;
+
+use Volkszaehler\Iterator;
+
 use Volkszaehler\Model;
 use Volkszaehler\View\HTTP;
 use Volkszaehler\Util;
@@ -42,8 +46,7 @@ abstract class View {
 
 	/**
 	 * @var HTTP\Request
-	 * @todo do we need this?
-	 * @todo why public? not via getter?
+	 * @todo do we need this? why public? not via getter?
 	 */
 	public $request;
 
@@ -108,7 +111,10 @@ abstract class View {
 				array_walk($data, array($this, 'add'));
 			}
 			else {
-				if ($data instanceof Model\Channel) {
+				if ($data instanceof Interpreter\InterpreterInterface) {
+					$this->addData($data);
+				}
+				elseif ($data instanceof Model\Channel) {
 					$this->addChannel($data);
 				}
 				elseif ($data instanceof Model\Aggregator) {
@@ -128,6 +134,10 @@ abstract class View {
 	}
 
 	protected abstract function render();
+
+	protected abstract function addData(Interpreter\InterpreterInterface $data);
+	protected abstract function addChannel(Model\Channel $channel);
+	protected abstract function addAggregator(Model\Aggregator $aggregator);
 	protected abstract function addException(\Exception $exception);
 	protected abstract function addDebug(Util\Debug $debug);
 }
diff --git a/backend/lib/View/XML.php b/backend/lib/View/XML.php
index e0638fe..4e21fce 100644
--- a/backend/lib/View/XML.php
+++ b/backend/lib/View/XML.php
@@ -23,6 +23,8 @@
 
 namespace Volkszaehler\View;
 
+use Volkszaehler\Interpreter;
+
 use Volkszaehler\View\HTTP;
 use Volkszaehler\Util;
 use Volkszaehler\Model;
@@ -38,6 +40,7 @@ class XML extends View {
 	protected $xmlRoot = NULL;
 	protected $xmlChannels = NULL;
 	protected $xmlAggregators = NULL;
+	protected $xmlDatas = NULL;
 
 	public function __construct(HTTP\Request $request, HTTP\Response $response) {
 		parent::__construct($request, $response);
@@ -53,7 +56,30 @@ class XML extends View {
 		$this->response->setHeader('Content-type', 'application/xml; charset=UTF-8');
 	}
 
-	public function addChannel(Model\Channel $channel, array $data = NULL) {
+	protected function addData(Interpreter\Interpreter $interpreter) {
+		$data = $interpreter->getValues();
+
+		$xmlData = $this->xmlDoc->createElement('data');
+
+		foreach ($data as $reading) {
+			$xmlReading = $this->xmlDoc->createElement('reading');
+
+			$xmlReading->setAttribute('timestamp', $reading[0]);	// hardcoded data fields for performance optimization
+			$xmlReading->setAttribute('value', $reading[1]);
+			$xmlReading->setAttribute('count', $reading[2]);
+
+			$xmlData->appendChild($xmlReading);
+		}
+
+		if (!isset($this->xmlDatas)) {
+			$this->xmlDatas = $this->xmlDoc->createElement('datas');
+			$this->xmlRoot->appendChild($this->xmlDatas);
+		}
+
+		$this->xmlDatas->appendChild($xmlData);
+	}
+
+	public function addChannel(Model\Channel $channel) {
 		$xmlChannel = $this->xmlDoc->createElement('channel');
 		$xmlChannel->setAttribute('uuid', $channel->getUuid());
 
@@ -64,22 +90,6 @@ class XML extends View {
 		$xmlChannel->appendChild($this->xmlDoc->createElement('resolution', (int) $channel->getResolution()));
 		$xmlChannel->appendChild($this->xmlDoc->createElement('cost', (float) $channel->getCost()));
 
-		if (isset($data)) {
-			$xmlData = $this->xmlDoc->createElement('data');
-
-			foreach ($data as $reading) {
-				$xmlReading = $this->xmlDoc->createElement('reading');
-
-				$xmlReading->setAttribute('timestamp', $reading['timestamp']);	// hardcoded data fields for performance optimization
-				$xmlReading->setAttribute('value', $reading['value']);
-				$xmlReading->setAttribute('count', $reading['count']);
-
-				$xmlData->appendChild($xmlReading);
-			}
-
-			$xmlChannel->appendChild($xmlData);
-		}
-
 		if (!isset($this->xmlChannels)) {
 			$this->xmlChannels = $this->xmlDoc->createElement('channels');
 			$this->xmlRoot->appendChild($this->xmlChannels);
@@ -139,7 +149,7 @@ class XML extends View {
 		$this->xmlRoot->appendChild($xmlException);
 	}
 
-	protected function renderResponse() {
+	protected function render() {
 		echo $this->xmlDoc->saveXML();
 	}