throw tx exception if NOT_SUPPORTED is used with an active tx

src/main/java/com/inteligr8/alfresco/annotations/aspect/RetryingTransactionAspect.java

@@ -136,8 +136,14 @@ public class RetryingTransactionAspect {
 						if (txl.isReadOnly())
 							throw new IllegalTransactionStateException("A read/write transaction exists where a read-only one is mandatory");
 				}
+			case NOT_SUPPORTED:
+				switch (AlfrescoTransactionSupport.getTransactionReadState()) {
+					case TXN_NONE:
+						return false;
+					default:
+						throw new IllegalTransactionStateException("A transaction exists and pausing it is not supported");
+				}
 			case SUPPORTS:
-			//case NOT_SUPPORTED:  not supported; we would have to create another thread to simulate
 				return false;
 			case REQUIRED:
 				switch (AlfrescoTransactionSupport.getTransactionReadState()) {