Index: /ModelExtender/src/de/uni_hildesheim/sse/model_extender/Main.java
===================================================================
--- /ModelExtender/src/de/uni_hildesheim/sse/model_extender/Main.java	(revision 233)
+++ /ModelExtender/src/de/uni_hildesheim/sse/model_extender/Main.java	(revision 234)
@@ -108,16 +108,14 @@
         	
         	// Copy Model
-        	Project clonedModel = new Project("clonedModel");
-        	for (int i = 0; i < variables.size(); i++) {
-				clonedModel.add(variables.get(i));
-			}
-        	for (int i = 0; i < constraints.size(); i++) {
-				clonedModel.add(constraints.get(i));
-			}
+        	Project clonedModel = cloneProject(variables,constraints);
+        			
         	// Test created model
-        	StringWriter sWriter = new StringWriter();
-        	IVMLWriter iWriter = new IVMLWriter(sWriter);
-        	clonedModel.accept(iWriter);
-        	System.out.println(sWriter);
+        	if(DEBUG)
+        	{
+        		StringWriter sWriter = new StringWriter();
+        		IVMLWriter iWriter = new IVMLWriter(sWriter);
+        		clonedModel.accept(iWriter);
+        		System.out.println(sWriter);
+        	}
         	
             // Extend model
@@ -132,5 +130,17 @@
         }
     }
-// this method add constraints to a model
+    private static Project cloneProject(List<AbstractVariable> variables,
+    		List<Constraint> constraints) {
+    	Project clonedModel = new Project("clonedModel");
+    	for (int i = 0; i < variables.size(); i++) {
+    		clonedModel.add(variables.get(i));
+    	}
+    	for (int i = 0; i < constraints.size(); i++) {
+    		clonedModel.add(constraints.get(i));
+    	}
+    	return clonedModel;
+    }
+
+	// this method add constraints to a model
     public static void extendModel(Project model, String constraint, File destinationDimacsFile)
             throws FileNotFoundException, IOException, MalformedFileException, ConstraintParserException {
@@ -156,16 +166,13 @@
             	
             	// Copy Model
-            	Project clonedModel = new Project("clonedModel");
-            	for (int i = 0; i < variables.size(); i++) {
-    				clonedModel.add(variables.get(i));
-    			}
-            	for (int i = 0; i < constraints.size(); i++) {
-    				clonedModel.add(constraints.get(i));
-    			}
+            	Project clonedModel = cloneProject(variables,constraints);
             	// Test created model
-            	StringWriter sWriter = new StringWriter();
-            	IVMLWriter iWriter = new IVMLWriter(sWriter);
-            	clonedModel.accept(iWriter);
-            	System.out.println(sWriter);
+            	if(DEBUG)
+            	{
+            		StringWriter sWriter = new StringWriter();
+            		IVMLWriter iWriter = new IVMLWriter(sWriter);
+            		clonedModel.accept(iWriter);
+            		System.out.println(sWriter);
+            	}
             	
                 // Extend model