diff -r 009efee954f7 -r 17f10b56c079 server/src/app/Models/MediaResource.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/server/src/app/Models/MediaResource.php	Thu Jun 02 18:24:19 2016 +0200
@@ -0,0 +1,60 @@
+<?php
+namespace CorpusParole\Models;
+
+use CorpusParole\Libraries\RdfModel\RdfModelResource;
+use CorpusParole\Libraries\Utils;
+
+use JsonSerializable;
+use Log;
+
+
+/**
+ */
+class MediaResource extends WebResource  {
+
+    private $master = false;
+    private $extent = -1;
+    private $extentMs = -1;
+
+    public function __construct(...$args) {
+        //print($graph->dump('html'));
+        parent::__construct(...$args);
+        list(,,$master) = $args;
+        $this->master = $master;
+    }
+
+    public function isMaster() {
+        return $this->master;
+    }
+
+    protected function doClearMemoizationCache() {
+        $this->extent = -1;
+        $this->extentMs = -1;
+    }
+
+    public function getExtent() {
+        if($this->extent === -1) {
+            $extent = $this->getLiteral("<http://purl.org/dc/terms/extent>");
+            $this->extent = is_null($extent)?null:$extent->getValue();
+        }
+
+        return $this->extent;
+    }
+
+    public function getExtentMs() {
+        if($this->extentMs === -1 ) {
+            $this->extentMs = Utils::iso8601IntervalToMillis($this->getExtent());
+        }
+        return $this->extentMs;
+    }
+
+
+    protected function jsonSerializeExtra() {
+        return [
+            'extent' => $this->getExtent(),
+            'extent_ms' => $this->getExtentMs(),
+            'master' => $this->isMaster()
+        ];
+    }
+
+}
\ No newline at end of file