Fix Nullpointer exception

Fix null pointer exception happening when getting a non existent SVG in
db

Issue-ID: CLAMP-424
Change-Id: I8941441b2af1ae2d54da977b467bde3abef52376
Signed-off-by: sebdet <sebastien.determe@intl.att.com>
diff --git a/src/main/java/org/onap/clamp/loop/LoopController.java b/src/main/java/org/onap/clamp/loop/LoopController.java
index b862780..7d41e48 100644
--- a/src/main/java/org/onap/clamp/loop/LoopController.java
+++ b/src/main/java/org/onap/clamp/loop/LoopController.java
@@ -116,12 +116,13 @@
 
     /**
      * Get the SVG representation of the loop
-     * 
+     *
      * @param loopName
      *        The loop name
      * @return The SVG representation
      */
     public String getSVGRepresentation(String loopName) {
-        return loopService.getLoop(loopName).getSvgRepresentation();
+        Loop loop = loopService.getLoop(loopName);
+        return loop != null ? loop.getSvgRepresentation() : null;
     }
 }