diff --git a/backend/lib/View/JSON.php b/backend/lib/View/JSON.php
index 2803131..ed18ddb 100644
--- a/backend/lib/View/JSON.php
+++ b/backend/lib/View/JSON.php
@@ -60,6 +60,32 @@ class JSON extends View {
 		$this->setPadding($request->getParameter('padding'));
 	}
 
+	/**
+	 * Add object to output
+	 *
+	 * @param mixed $data
+	 */
+	public function add($data) {
+		if ($data instanceof Interpreter\InterpreterInterface) {
+			$this->addData($data);
+		}
+		elseif ($data instanceof Model\Entity) {
+			$this->addEntity($data);
+		}
+		elseif ($data instanceof \Exception) {
+			$this->addException($data);
+		}
+		elseif ($data instanceof Util\Debug) {
+			$this->addDebug($data);
+		}
+		elseif ($data instanceof Util\JSON || is_array($data)) {
+			$this->addArray($data);
+		}
+		else {
+			throw new \Exception('Can\'t show ' . get_class($data));
+		}
+	}
+
 	/**
 	 * Process, encode and print output
 	 *
@@ -161,17 +187,18 @@ class JSON extends View {
 	 * @param \Exception $exception
 	 * @param boolean $debug
 	 */
-	protected function addException(\Exception $exception, $debug = FALSE) {
+	protected function addException(\Exception $exception) {
 		$exceptionInfo = array(
-			'type' => get_class($exception),
 			'message' => $exception->getMessage(),
+			'type' => get_class($exception),
 			'code' => $exception->getCode()
 		);
 
-		if ($debug) {
-			$debugInfo = array('file' => $exception->getFile(),
+		if (Util\Debug::isActivated()) {
+			$debugInfo = array(
+				'file' => $exception->getFile(),
 				'line' => $exception->getLine(),
-				'trace' => $exception->getTrace()
+				'backtrace' => $exception->getTrace()
 			);
 
 			$this->json['exception'] = array_merge($exceptionInfo, $debugInfo);
@@ -190,7 +217,7 @@ class JSON extends View {
 		$data = $interpreter->getValues($this->request->getParameter('tuples'), $this->request->getParameter('group'));
 
 		$this->json['data'] = array(
-			'uuid'		=> $interpreter->getUuid(),
+			'uuid'		=> $interpreter->getEntity()->getUuid(),
 			'count'		=> count($data),
 			'first'		=> (isset($data[0][0])) ? $data[0][0] : NULL,
 			'last'		=> (isset($data[count($data)-1][0])) ? $data[count($data)-1][0] : NULL,
@@ -212,18 +239,6 @@ class JSON extends View {
 		}
 	}
 
-	/**
-	 * Overloaded to support arrays
-	 */
-	public function add($data) {
-		if ($data instanceof Util\JSON || is_array($data)) {
-			$this->addArray($data);
-		}
-		else {
-			parent::add($data);
-		}
-	}
-
 	/*
 	 * Setter & getter
 	 */
diff --git a/backend/lib/View/JpGraph.php b/backend/lib/View/JpGraph.php
index 3e51f45..8f61e69 100644
--- a/backend/lib/View/JpGraph.php
+++ b/backend/lib/View/JpGraph.php
@@ -24,7 +24,6 @@
 namespace Volkszaehler\View;
 
 use Volkszaehler\Interpreter;
-
 use Volkszaehler\Model;
 use Volkszaehler\Util;
 
@@ -45,20 +44,35 @@ require_once VZ_BACKEND_DIR . '/lib/vendor/JpGraph/jpgraph_date.php';
  */
 class JpGraph extends View {
 	/**
-	 * indicator => ynaxis[n] mapping
+	 * @var indicator => ynaxis[n] mapping
 	 */
 	protected $axes = array();
 
 	protected $channels = array();
 
-	const WIDTH = 800;
-	const HEIGHT = 400;
+	/**
+	 * @var default width
+	 */
+	protected $width = 800;
 
-	protected static $colors = array('chartreuse', 'chocolate1', 'cyan', 'blue', 'lightcyan4', 'gold');
+	/**
+	 * @var default height
+	 */
+	protected $height = 400;
 
+	/**
+	 * @var color palette for the scatter plots
+	 * This are the same colors as in the webfronted
+	 */
+	protected static $colors = array('#83CAFF', '#7E0021', '#579D1C', '#FFD320', '#FF420E', '#004586', '#0084D1', '#C5000B', '#FF950E', '#4B1F6F', '#AECF00', '#314004');
+
+	/**
+	 * @var JPGrpah handle
+	 */
 	protected $graph;
 
 	/**
+	 * Constructor
 	 *
 	 * @param HTTP\Request $request
 	 * @param HTTP\Response $response
@@ -67,10 +81,18 @@ class JpGraph extends View {
 	public function __construct(HTTP\Request $request, HTTP\Response $response, $format = 'png') {
 		parent::__construct($request, $response);
 
-		$width = $this->request->getParameter('width') ? $this->request->getParameter('width') : self::WIDTH;
-		$height = $this->request->getParameter('height') ? $this->request->getParameter('height') : self::HEIGHT;
+		// to enabled jpgraphs graphical exception handler
+		restore_exception_handler();
 
-		$this->graph = new \Graph($width, $height);
+		if ($this->request->getParameter('width')) {
+			$this->width = $this->request->getParameter('width');
+		}
+
+		if ($this->request->getParameter('height')) {
+			$this->height = $this->request->getParameter('height');
+		}
+
+		$this->graph = new \Graph($this->width, $this->height);
 
 		$this->graph->img->SetImgFormat($format);
 
@@ -90,7 +112,29 @@ class JpGraph extends View {
 		$this->graph->xaxis->SetLabelAngle(45);
 		$this->graph->xaxis->SetLabelFormatCallback(function($label) { return date('j.n.y G:i', $label); });
 
-		//$this->graph->img->SetAntiAliasing();
+		if (function_exists('imageantialias')) {
+			$this->graph->img->SetAntiAliasing();
+		}
+	}
+
+	/**
+	 * Add object to output
+	 *
+	 * @param mixed $data
+	 */
+	public function add($data) {
+		if ($data instanceof Interpreter\Interpreter) {
+			$this->addData($data);
+		}
+		elseif($data instanceof Interpreter\AggregatorInterpreter) {
+			foreach ($data->getEntity()->getChildren() as $child) {
+				$this->add($child);
+			}
+		}
+		else {
+			// suppress other classes
+			//throw new \Exception('Can\'t show ' . get_class($data));
+		}
 	}
 
 	/**
@@ -99,8 +143,8 @@ class JpGraph extends View {
 	 * @param $obj
 	 * @param $data
 	 */
-	public function addData(Interpreter\Interpreter $interpreter){
-		$data = $interpreter->getValues(800);
+	public function addData(Interpreter\InterpreterInterface $interpreter){
+		$data = $interpreter->getValues($this->width/4);
 
 		if (count($data) > 0) {
 			$count = count($this->channels);
@@ -114,7 +158,7 @@ class JpGraph extends View {
 			// Create the scatter plot
 			$plot = new \ScatterPlot($yData, $xData);
 
-			$plot->setLegend($interpreter->getChannel()->getProperty('title') . ':  [' . $interpreter->getChannel()->getDefinition()->getUnit() . ']');
+			$plot->setLegend($interpreter->getEntity()->getProperty('title') . ':  [' . $interpreter->getEntity()->getDefinition()->getUnit() . ']');
 			$plot->SetLinkPoints(TRUE, self::$colors[$count]);
 
 			$plot->mark->SetColor(self::$colors[$count]);
@@ -122,7 +166,7 @@ class JpGraph extends View {
 			$plot->mark->SetType(MARK_DIAMOND);
 			$plot->mark->SetWidth(1);
 
-			$axis = $this->getAxisIndex($interpreter->getChannel());
+			$axis = $this->getAxisIndex($interpreter->getEntity());
 			if ($axis >= 0) {
 				$this->graph->AddY($axis, $plot);
 			}
@@ -130,22 +174,10 @@ class JpGraph extends View {
 				$this->graph->Add($plot);
 			}
 
-			$this->channels[] = $interpreter->getChannel();
+			$this->channels[] = $interpreter->getEntity();
 		}
 	}
 
-	public function addChannel(Model\Channel $channel) {
-		throw new \Exception(get_class($this) . ' cant show ' . get_class($channel));
-	}
-
-	public function addAggregator(Model\Aggregator $aggregator) {
-		throw new \Exception(get_class($this) . ' cant show ' . get_class($aggregator));
-	}
-
-	public function addDebug(Util\Debug $debug) {
-		throw new \Exception(get_class($this) . ' cant show ' . get_class($debug));
-	}
-
 	/**
 	 * Shows exception
 	 *
@@ -197,9 +229,9 @@ class JpGraph extends View {
 	protected function render() {
 		$this->graph->SetMargin(75, (count($this->axes) - 1) * 65 + 10, 20, 90);
 
-		// Display the graph
-		//$this->graph->Stroke();
+		// display the graph
+		$this->graph->Stroke();
 	}
 }
 
-?>
\ No newline at end of file
+?>
diff --git a/backend/lib/View/View.php b/backend/lib/View/View.php
index 114c29f..cc81114 100644
--- a/backend/lib/View/View.php
+++ b/backend/lib/View/View.php
@@ -24,9 +24,6 @@
 namespace Volkszaehler\View;
 
 use Volkszaehler\Interpreter;
-
-use Volkszaehler\Iterator;
-
 use Volkszaehler\Model;
 use Volkszaehler\View\HTTP;
 use Volkszaehler\Util;
@@ -36,7 +33,6 @@ use Volkszaehler\Util;
  *
  * @package default
  * @author Steffen Vogel <info@steffenvogel.de>
- *
  */
 abstract class View {
 	/**
@@ -88,7 +84,8 @@ abstract class View {
 	 * @param \Exception $exception
 	 */
 	final public function exceptionHandler(\Exception $exception) {
-		$this->addException($exception, Util\Debug::isActivated());
+		$this->add($exception);
+		echo $exception;
 
 		$code = ($exception->getCode() == 0 || !HTTP\Response::getCodeDescription($exception->getCode())) ? 400 : $exception->getCode();
 		$this->response->setCode($code);
@@ -97,40 +94,18 @@ abstract class View {
 		die();
 	}
 
+	/**
+	 * Render response and send it to the client
+	 */
 	public function send() {
 		if (Util\Debug::isActivated()) {
-			$this->addDebug(Util\Debug::getInstance());
+			$this->add(Util\Debug::getInstance());
 		}
 
 		$this->render();
 		$this->response->send();
 	}
 
-	/**
-	 * Add object to output
-	 *
-	 * @param mixed $data
-	 */
-	public function add($data) {
-		if (isset($data)) {
-			if ($data instanceof Interpreter\InterpreterInterface) {
-				$this->addData($data);
-			}
-			elseif ($data instanceof Model\Entity) {
-				$this->addEntity($data);
-			}
-			elseif ($data instanceof \Exception) {
-				$this->addException($data);
-			}
-			elseif ($data instanceof Util\Debug) {
-				$this->addDebug($data);
-			}
-			else {
-				throw new \Exception('Can\'t show ' . get_class($data));
-			}
-		}
-	}
-
 	/**
 	 * Sets caching mode for the browser
 	 *
@@ -141,7 +116,7 @@ abstract class View {
 	public function setCaching($mode, $value) {
 		switch ($mode) {
 			case 'modified':	// Last-modified
-				//$this->response->setHeader('Last-Modified', gmdate('D, d M Y H:i:s', $value) . ' GMT');
+				$this->response->setHeader('Last-Modified', gmdate('D, d M Y H:i:s', $value) . ' GMT');
 
 			case 'etag':		// Etag
 				throw new Exception('This caching mode is not implemented');
@@ -150,7 +125,7 @@ abstract class View {
 				$this->response->setHeader('Expires', gmdate('D, d M Y H:i:s', $value) . ' GMT');
 				break;
 
-			case 'age':			// Cache-control: max-age=
+			case 'age':		// Cache-control: max-age=
 				$this->response->setHeader('Cache-control', 'max-age=' . $value);
 				break;
 
@@ -160,16 +135,12 @@ abstract class View {
 				$this->response->setHeader('Pragma', 'no-cache');
 
 			default:
-				throw new Exception('Unknown caching mode');
+				throw new Exception('Unknown caching mode: ' . $mode);
 		}
 	}
 
+	public abstract function add($object);
 	protected abstract function render();
-
-	protected abstract function addData(Interpreter\InterpreterInterface $data);
-	protected abstract function addEntity(Model\Entity $entity);
-	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 7f427ac..7c02ef3 100644
--- a/backend/lib/View/XML.php
+++ b/backend/lib/View/XML.php
@@ -62,6 +62,32 @@ class XML extends View {
 		$this->xmlDoc->appendChild($this->xmlRoot);
 	}
 
+	/**
+	 * Add object to output
+	 *
+	 * @param mixed $data
+	 */
+	public function add($data) {
+		if ($data instanceof Interpreter\InterpreterInterface) {
+			$this->addData($data);
+		}
+		elseif ($data instanceof Model\Entity) {
+			$this->addEntity($data);
+		}
+		elseif ($data instanceof \Exception) {
+			//$this->addException($data);
+		}
+		elseif ($data instanceof Util\Debug) {
+			//$this->addDebug($data);
+		}
+		elseif (is_array($data)) {
+			$this->xmlRoot->appendChild($this->convertArray($data));
+		}
+		else {
+			throw new \Exception('Can\'t show ' . get_class($data));
+		}
+	}
+
 	/**
 	 * Process, encode and print output
 	 *
@@ -155,12 +181,16 @@ class XML extends View {
 	 */
 	protected function addException(\Exception $exception) {
 		$xmlException = $this->xmlDoc->createElement('exception');
-
 		$xmlException->setAttribute('code', $exception->getCode());
+		$xmlException->setAttribute('type', get_class($exception));
+
 		$xmlException->appendChild($this->xmlDoc->createElement('message', $exception->getMessage()));
-		$xmlException->appendChild($this->xmlDoc->createElement('line', $exception->getLine()));
-		$xmlException->appendChild($this->xmlDoc->createElement('file', $exception->getFile()));
-		$xmlException->appendChild($this->convertTrace($exception->getTrace()));
+
+		if (Util\Debug::isActivated()) {
+			$xmlException->appendChild($this->xmlDoc->createElement('file', $exception->getFile()));
+			$xmlException->appendChild($this->xmlDoc->createElement('line', $exception->getLine()));
+			$xmlException->appendChild($this->convertTrace($exception->getTrace()));
+		}
 
 		$this->xmlRoot->appendChild($xmlException);
 	}
@@ -182,7 +212,7 @@ class XML extends View {
 			$xmlTuples->appendChild($xmlTuple);
 		}
 
-		$xmlData->appendChild($this->xmlDoc->createElement('uuid', $interpreter->getUuid()));
+		$xmlData->appendChild($this->xmlDoc->createElement('uuid', $interpreter->getEntity()->getUuid()));
 		$xmlData->appendChild($this->xmlDoc->createElement('count', count($data)));
 		$xmlData->appendChild($this->xmlDoc->createElement('first', (isset($data[0][0])) ? $data[0][0] : NULL));
 		$xmlData->appendChild($this->xmlDoc->createElement('last', (isset($data[count($data)-1][0])) ? $data[count($data)-1][0] : NULL));
@@ -265,18 +295,6 @@ class XML extends View {
 
 		return $xmlTraces;
 	}
-
-	/**
-	 * Overloaded to support arrays
-	 */
-	public function add($data) {
-		if (is_array($data)) {
-			$this->xmlRoot->appendChild($this->convertArray($data));
-		}
-		else {
-			parent::add($data);
-		}
-	}
 }
 
 ?>