#171: add a PathMatcher based on the subscription header

Author: laurentpeters

lib/src/main/java/ua/naiksoftware/stomp/StompClient.java

@@ -316,4 +316,11 @@ public boolean isConnected() {
     public void setLegacyWhitespace(boolean legacyWhitespace) {
         this.legacyWhitespace = legacyWhitespace;
     }
+    
+    /** returns the to topic (subscription id) corresponding to a given destination  
+     * @param dest the destination
+     * @return the topic (subscription id) or null if no topic corresponds to the destination */
+    public String getTopicId(String dest) {
+        return topics.get(dest);
+    }
 }

lib/src/main/java/ua/naiksoftware/stomp/pathmatcher/SubscriptionPathMatcher.java

@@ -0,0 +1,16 @@
+package ua.naiksoftware.stomp.pathmatcher;
+
+import ua.naiksoftware.stomp.dto.StompHeader;
+import ua.naiksoftware.stomp.dto.StompMessage;
+
+public class SubscriptionPathMatcher implements PathMatcher {
+
+    @Override
+    public boolean matches(String path, StompMessage msg) {
+       // Compare subscription
+        String pathSubscription = stompClient.getTopicId(path);
+        if (pathSubscription == null) return false;
+        String subscription = msg.findHeader(StompHeader.SUBSCRIPTION);
+        return pathSubscription.equals(subscription);
+    }
+}