Bugfix/topic alias mapping

src/main/java/org/mqttbee/api/mqtt/mqtt5/message/publish/Mqtt5PublishBuilder.java

@@ -40,6 +40,7 @@
 import java.util.concurrent.TimeUnit;
 import java.util.function.Function;
 
+import static org.mqttbee.api.mqtt.mqtt5.message.publish.TopicAliasUsage.*;
 import static org.mqttbee.mqtt.message.publish.MqttPublish.DEFAULT_TOPIC_ALIAS_USAGE;
 import static org.mqttbee.mqtt.message.publish.MqttPublish.MESSAGE_EXPIRY_INTERVAL_INFINITY;
 
@@ -182,7 +183,8 @@ public Mqtt5PublishBuilder<P> correlationData(@Nullable final ByteBuffer correla
 
     @NotNull
     public Mqtt5PublishBuilder<P> topicAliasUsage(@NotNull final TopicAliasUsage topicAliasUsage) {
-        Preconditions.checkNotNull(topicAliasUsage);
+        Preconditions.checkArgument(
+                topicAliasUsage == MUST_NOT || topicAliasUsage == MAY || topicAliasUsage == MAY_OVERWRITE);
         this.topicAliasUsage = topicAliasUsage;
         return this;
     }

src/main/java/org/mqttbee/mqtt/MqttClientConnectionData.java

@@ -26,6 +26,7 @@
 import org.mqttbee.api.mqtt.mqtt5.auth.Mqtt5EnhancedAuthProvider;
 import org.mqttbee.mqtt.datatypes.MqttTopicImpl;
 import org.mqttbee.mqtt.datatypes.MqttVariableByteInteger;
+import org.mqttbee.util.collections.IntMap;
 
 import java.util.Optional;
 
@@ -37,7 +38,8 @@ public class MqttClientConnectionData implements Mqtt5ClientConnectionData, Mqtt
     private int keepAlive;
     private long sessionExpiryInterval;
     private final int receiveMaximum;
-    private final MqttTopicImpl[] topicAliasMapping;
+    private final int topicAliasMaximum;
+    private final IntMap<MqttTopicImpl> topicAliasMapping;
     private final int maximumPacketSize;
     private final int subscriptionIdentifierMaximum;
     private final Mqtt5EnhancedAuthProvider enhancedAuthProvider;
@@ -56,7 +58,8 @@ public MqttClientConnectionData(
         this.keepAlive = keepAlive;
         this.sessionExpiryInterval = sessionExpiryInterval;
         this.receiveMaximum = receiveMaximum;
-        this.topicAliasMapping = (topicAliasMaximum == 0) ? null : new MqttTopicImpl[topicAliasMaximum];
+        this.topicAliasMaximum = topicAliasMaximum;
+        this.topicAliasMapping = (topicAliasMaximum == 0) ? null : IntMap.range(1, topicAliasMaximum);
         this.maximumPacketSize = maximumPacketSize;
         this.subscriptionIdentifierMaximum =
                 MqttVariableByteInteger.FOUR_BYTES_MAX_VALUE; // TODO CONNECT + CONNACK user properties
@@ -92,11 +95,11 @@ public int getReceiveMaximum() {
 
     @Override
     public int getTopicAliasMaximum() {
-        return (topicAliasMapping == null) ? 0 : topicAliasMapping.length;
+        return topicAliasMaximum;
     }
 
     @Nullable
-    public MqttTopicImpl[] getTopicAliasMapping() {
+    public IntMap<MqttTopicImpl> getTopicAliasMapping() {
         return topicAliasMapping;
     }
 

src/main/java/org/mqttbee/mqtt/MqttServerConnectionData.java

@@ -56,9 +56,10 @@ public MqttServerConnectionData(
             final int receiveMaximum, final int topicAliasMaximum, final int maximumPacketSize,
             final MqttQos maximumQos, final boolean isRetainAvailable, final boolean isWildcardSubscriptionAvailable,
             final boolean isSubscriptionIdentifierAvailable, final boolean isSharedSubscriptionAvailable) {
+
         this.receiveMaximum = receiveMaximum;
         this.maximumPacketSize = maximumPacketSize;
-        this.topicAliasMapping = topicAliasMaximum == 0 ? null : new MqttTopicAliasMapping(topicAliasMaximum);
+        this.topicAliasMapping = (topicAliasMaximum == 0) ? null : new MqttTopicAliasMapping(topicAliasMaximum);
         this.maximumQos = maximumQos;
         this.isRetainAvailable = isRetainAvailable;
         this.isWildcardSubscriptionAvailable = isWildcardSubscriptionAvailable;
@@ -73,7 +74,7 @@ public int getReceiveMaximum() {
 
     @Override
     public int getTopicAliasMaximum() {
-        return (topicAliasMapping == null) ? 0 : topicAliasMapping.size();
+        return (topicAliasMapping == null) ? 0 : topicAliasMapping.getTopicAliasMaximum();
     }
 
     @Nullable

src/main/java/org/mqttbee/mqtt/codec/decoder/mqtt5/Mqtt5PublishDecoder.java

@@ -36,6 +36,7 @@
 import org.mqttbee.mqtt.message.publish.MqttStatefulPublish;
 import org.mqttbee.mqtt.netty.ChannelAttributes;
 import org.mqttbee.util.ByteBufferUtil;
+import org.mqttbee.util.collections.IntMap;
 
 import javax.inject.Inject;
 import javax.inject.Singleton;
@@ -183,20 +184,20 @@ public MqttStatefulPublish decode(
 
         boolean isNewTopicAlias = false;
         if (topicAlias != DEFAULT_NO_TOPIC_ALIAS) {
-            final MqttTopicImpl[] topicAliasMapping = clientConnectionData.getTopicAliasMapping();
-            if ((topicAliasMapping == null) || (topicAlias > topicAliasMapping.length)) {
+            final IntMap<MqttTopicImpl> topicAliasMapping = clientConnectionData.getTopicAliasMapping();
+            if ((topicAliasMapping == null) || (topicAlias > clientConnectionData.getTopicAliasMaximum())) {
                 throw new MqttDecoderException(
                         Mqtt5DisconnectReasonCode.TOPIC_ALIAS_INVALID,
                         "topic alias must not exceed topic alias maximum");
             }
             if (topic == null) {
-                topic = topicAliasMapping[topicAlias - 1];
+                topic = topicAliasMapping.get(topicAlias);
                 if (topic == null) {
                     throw new MqttDecoderException(
                             Mqtt5DisconnectReasonCode.TOPIC_ALIAS_INVALID, "topic alias has no mapping");
                 }
             } else {
-                topicAliasMapping[topicAlias - 1] = topic;
+                topicAliasMapping.put(topicAlias, topic);
                 isNewTopicAlias = true;
             }
         } else if (topic == null) {

src/main/java/org/mqttbee/mqtt/message/publish/MqttTopicAliasMapping.java

@@ -21,32 +21,35 @@
 import org.mqttbee.api.mqtt.mqtt5.message.publish.TopicAliasUsage;
 import org.mqttbee.mqtt.datatypes.MqttTopicImpl;
 
+import javax.annotation.concurrent.NotThreadSafe;
 import java.util.HashMap;
 import java.util.Random;
 
 /**
  * @author Silvio Giebl
  */
+@NotThreadSafe
 public class MqttTopicAliasMapping {
 
     private static final Random random = new Random();
 
-    private final int size;
+    private final int topicAliasMaximum;
     private final HashMap<String, Integer> hashMap;
     private int nextTopicAlias;
 
-    public MqttTopicAliasMapping(final int size) {
-        this.size = size;
-        hashMap = new HashMap<>(size);
+    public MqttTopicAliasMapping(final int topicAliasMaximum) {
+        this.topicAliasMaximum = topicAliasMaximum;
+        hashMap = new HashMap<>(topicAliasMaximum);
         nextTopicAlias = 1;
     }
 
     public int set(@NotNull final MqttTopicImpl topic, @NotNull final TopicAliasUsage topicAliasUsage) {
         int topicAlias = MqttStatefulPublish.DEFAULT_NO_TOPIC_ALIAS;
         if (topicAliasUsage != TopicAliasUsage.MUST_NOT) {
-            if (nextTopicAlias == size) {
+            if (nextTopicAlias > topicAliasMaximum) {
                 if (topicAliasUsage == TopicAliasUsage.MAY_OVERWRITE) {
-                    topicAlias = random.nextInt(size) + 1;
+                    topicAlias = random.nextInt(topicAliasMaximum) + 1;
+                    hashMap.values().remove(topicAlias);
                     hashMap.put(topic.toString(), topicAlias);
                 }
             } else {
@@ -63,8 +66,8 @@ public int get(@NotNull final MqttTopicImpl topic) {
         return (topicAlias == null) ? MqttStatefulPublish.DEFAULT_NO_TOPIC_ALIAS : topicAlias;
     }
 
-    public int size() {
-        return size;
+    public int getTopicAliasMaximum() {
+        return topicAliasMaximum;
     }
 
 }