Do not filter not existent senders/receivers

git-svn-id: https://scm.gforge.inria.fr/authscm/ycadoret/svn/gazelle/Maven/gazelle-proxy/trunk@20947 356b4b1a-1d2b-0410-8bf1-ffa24008f01e

gazelle-proxy-datamodel/src/main/java/net/ihe/gazelle/proxy/dao/MessageFilterStep.java

@@ -222,6 +222,14 @@ public class MessageFilterStep implements MessageFilter {
 			}
 
 			Set<Crit> paths = new HashSet<Crit>();
+
+			if (critSenders.size() == 0) {
+				filterPathFrom = false;
+			}
+			if (critReceivers.size() == 0) {
+				filterPathReceiver = false;
+			}
+
 			if (filterPathFrom && filterPathReceiver) {
 				for (Crit critSender : critSenders) {
 					for (Crit critReceiver : critReceivers) {