Allow InterceptHandler to specify the messages they can intercept. This allows us to improve the performance of the broker interceptor, and will make log traces more clear.

- Add methods to return an unique identifier and the supported message types at the InterceptHandler interface.
- Include a default implementation of the new methods in the AbstractInterceptHandler. By default, all the interceptors will be able to handle any message (same as before).
- Comment verifyNoMoreInteractions() call from the BrokerInterceptorTest.testAddAndRemoveInterceptHandler(). The removeInterceptHandler() method of the broker interceptor
  polls the InterceptHandler, so an interaction will always exist after the call to onSubscribe().

broker/src/main/java/io/moquette/interception/messages/InterceptAbstractMessage.java

@@ -20,7 +20,7 @@ import io.moquette.parser.proto.messages.AbstractMessage;
 /**
  * @author Wagner Macedo
  */
-public abstract class InterceptAbstractMessage {
+public abstract class InterceptAbstractMessage implements InterceptMessage {
     private final AbstractMessage msg;
 
     InterceptAbstractMessage(AbstractMessage msg) {

broker/src/main/java/io/moquette/interception/messages/InterceptAcknowledgedMessage.java

@@ -2,7 +2,7 @@ package io.moquette.interception.messages;
 
 import static io.moquette.spi.IMessagesStore.StoredMessage;
 
-public class InterceptAcknowledgedMessage {
+public class InterceptAcknowledgedMessage implements InterceptMessage {
 	final private StoredMessage msg;
 	private final String username;
 	private final String topic;

broker/src/main/java/io/moquette/interception/messages/InterceptConnectionLostMessage.java

@@ -3,7 +3,7 @@ package io.moquette.interception.messages;
 /**
  * @author Wagner Macedo
  */
-public class InterceptConnectionLostMessage {
+public class InterceptConnectionLostMessage implements InterceptMessage {
     private final String clientID;
     private final String username;
 

broker/src/main/java/io/moquette/interception/messages/InterceptDisconnectMessage.java

@@ -3,7 +3,7 @@ package io.moquette.interception.messages;
 /**
  * @author Wagner Macedo
  */
-public class InterceptDisconnectMessage {
+public class InterceptDisconnectMessage implements InterceptMessage {
     private final String clientID;
     private final String username;
 

broker/src/main/java/io/moquette/interception/messages/InterceptMessage.java

@@ -0,0 +1,10 @@
+package io.moquette.interception.messages;
+
+/**
+ * An interface that sets the root of the interceptor messages type hierarchy.
+ * @author lbarrios
+ *
+ */
+public interface InterceptMessage {
+
+}

broker/src/main/java/io/moquette/interception/messages/InterceptSubscribeMessage.java

@@ -6,7 +6,7 @@ import io.moquette.spi.impl.subscriptions.Subscription;
 /**
  * @author Wagner Macedo
  */
-public class InterceptSubscribeMessage {
+public class InterceptSubscribeMessage implements InterceptMessage {
     private final Subscription subscription;
     private final String username;
 

broker/src/main/java/io/moquette/interception/messages/InterceptUnsubscribeMessage.java

@@ -3,7 +3,7 @@ package io.moquette.interception.messages;
 /**
  * @author Wagner Macedo
  */
-public class InterceptUnsubscribeMessage {
+public class InterceptUnsubscribeMessage implements InterceptMessage {
     private final String topicFilter;
     private final String clientID;
     private final String username;