added a testcase and fixed Issue-918

org.eclipse.paho.mqttv5.client.test/src/test/java/org/eclipse/paho/mqttv5/common/utils/MqttTopicTest.java

@@ -38,7 +38,7 @@ public class MqttTopicTest {
 		String[][] matchingTopics = new String[][] { { "sport/tennis/player1/#", "sport/tennis/player1" },
 				{ "sport/tennis/player1/#", "sport/tennis/player1/ranking" },
 				{ "sport/tennis/player1/#", "sport/tennis/player1/score/wimbledon" }, { "sport/#", "sport" },
-				{ "#", "sport/tennis/player1" } };
+				{ "#", "sport/tennis/player1" } , {"sport/+/player1/ranking/#","sport/tennis/player1/ranking"} };
 
 		for (String[] pair : matchingTopics) {
 			Assert.assertTrue(pair[0] + " should match " + pair[1], MqttTopicValidator.isMatched(pair[0], pair[1]));

org.eclipse.paho.mqttv5.client/src/main/java/org/eclipse/paho/mqttv5/common/util/MqttTopicValidator.java

@@ -5,22 +5,19 @@ import java.io.UnsupportedEncodingException;
 public class MqttTopicValidator {
 
   /**
-	 * The forward slash (/) is used to separate each level within a topic tree and
+   * The forward slash (/) is used to separate each level within a topic tree and provide a hierarchical structure to
-	 * provide a hierarchical structure to the topic space. The use of the topic
+   * the topic space. The use of the topic level separator is significant when the two wildcard characters are
-	 * level separator is significant when the two wildcard characters are
    * encountered in topics specified by subscribers.
    */
   public static final String TOPIC_LEVEL_SEPARATOR = "/";
 
   /**
-	 * Multi-level wildcard The number sign (#) is a wildcard character that matches
+   * Multi-level wildcard The number sign (#) is a wildcard character that matches any number of levels within a topic.
-	 * any number of levels within a topic.
    */
   public static final String MULTI_LEVEL_WILDCARD = "#";
 
   /**
-	 * Single-level wildcard The plus sign (+) is a wildcard character that matches
+   * Single-level wildcard The plus sign (+) is a wildcard character that matches only one topic level.
-	 * only one topic level.
    */
   public static final String SINGLE_LEVEL_WILDCARD = "+";
 
@@ -88,10 +85,8 @@ public class MqttTopicValidator {
       // - The multi-level wildcard must be the last character used within
       // the topic tree
       if (Strings.countMatches(topicString, MULTI_LEVEL_WILDCARD) > 1
-					|| (topicString.contains(MULTI_LEVEL_WILDCARD)
+          || (topicString.contains(MULTI_LEVEL_WILDCARD) && !topicString.endsWith(MULTI_LEVEL_WILDCARD_PATTERN))) {
-							&& !topicString.endsWith(MULTI_LEVEL_WILDCARD_PATTERN))) {
+        throw new IllegalArgumentException("Invalid usage of multi-level wildcard in topic string: " + topicString);
-				throw new IllegalArgumentException(
-						"Invalid usage of multi-level wildcard in topic string: " + topicString);
       }
 
       // 2) Check single-level wildcard
@@ -134,9 +129,8 @@ public class MqttTopicValidator {
       if (chars[i] == singleLevelWildcardChar) {
         // prev and next can be only '/' or none
         if (prev != topicLevelSeparatorChar && prev != NUL || next != topicLevelSeparatorChar && next != NUL) {
-					throw new IllegalArgumentException(
+          throw new IllegalArgumentException(String
-							String.format("Invalid usage of single-level wildcard in topic string '%s'!",
+              .format("Invalid usage of single-level wildcard in topic string '%s'!", new Object[] { topicString }));
-									new Object[] { topicString }));
 
         }
       }
@@ -170,8 +164,7 @@ public class MqttTopicValidator {
     while (filterPos < filterLen && topicPos < topicLen) {
       if (topicFilter.charAt(filterPos) == '#') {
         /*
-                                 * next 'if' will break when topicFilter = topic/# and topicName topic/A/,
+         * next 'if' will break when topicFilter = topic/# and topicName topic/A/, but they are matched
-                                 * but they are matched
          */
         topicPos = topicLen;
         filterPos = filterLen;
@@ -196,20 +189,35 @@ public class MqttTopicValidator {
       return true;
     } else {
       /*
-			 * https://github.com/eclipse/paho.mqtt.java/issues/418 Covers edge case to
+       * https://github.com/eclipse/paho.mqtt.java/issues/418 Covers edge case to match sport/# to sport
-			 * match sport/# to sport
        */
       if ((topicFilter.length() - filterPos > 0) && (topicPos == topicLen)) {
         if (topicName.charAt(topicPos - 1) == '/' && topicFilter.charAt(filterPos) == '#')
           return true;
-                               if (topicFilter.length() - filterPos > 1
+        if (topicFilter.length() - filterPos > 1 && topicFilter.substring(filterPos, filterPos + 2).equals("/#")) {
-                                       && topicFilter.substring(filterPos, filterPos + 2).equals("/#")) {
           if ((topicFilter.length() - topicName.length()) == 2
               && topicFilter.substring(topicFilter.length() - 2, topicFilter.length()).equals("/#")) {
             return true;
           }
         }
       }
+      /*
+       * https://github.com/eclipse/paho.mqtt.java/issues/918
+       * covers cases that include more then one wildcard
+       * sport/+/tennis/#
+       */
+        String[] topicFilterParts = topicFilter.split(TOPIC_LEVEL_SEPARATOR);
+        String[] topicParts = topicName.split(TOPIC_LEVEL_SEPARATOR);
+        if(topicFilterParts.length -1 == topicParts.length &&
+            topicFilterParts[topicFilterParts.length-1].equals( MULTI_LEVEL_WILDCARD)) {      
+          for (int i = 0; i<topicParts.length;i++) {
+            if(!topicParts[i].equals(topicFilterParts[i]) && !topicFilterParts[i].equals(SINGLE_LEVEL_WILDCARD)) {
+              return false;
+            }       
+          }
+          return true;
+        }  
+      
     }
     return false;
   }