Added implementation of retained store in H2

broker/src/main/java/io/moquette/persistence/H2Builder.java

@@ -2,6 +2,7 @@ package io.moquette.persistence;
 
 import io.moquette.BrokerConstants;
 import io.moquette.broker.IQueueRepository;
+import io.moquette.broker.IRetainedRepository;
 import io.moquette.broker.ISubscriptionsRepository;
 import io.moquette.broker.config.IConfig;
 import org.h2.mvstore.MVStore;
@@ -57,4 +58,8 @@ public class H2Builder {
     public IQueueRepository queueRepository() {
         return new H2QueueRepository(mvStore);
     }
+
+    public IRetainedRepository retainedRepository() {
+        return new H2RetainedRepository(mvStore);
+    }
 }

broker/src/main/java/io/moquette/persistence/H2RetainedRepository.java

@@ -0,0 +1,55 @@
+package io.moquette.persistence;
+
+import io.moquette.broker.IRetainedRepository;
+import io.moquette.broker.RetainedMessage;
+import io.moquette.broker.subscriptions.Topic;
+import io.netty.buffer.ByteBuf;
+import io.netty.handler.codec.mqtt.MqttPublishMessage;
+import org.h2.mvstore.MVMap;
+import org.h2.mvstore.MVStore;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+public class H2RetainedRepository implements IRetainedRepository {
+
+    private final MVMap<Topic, RetainedMessage> queueMap;
+
+    public H2RetainedRepository(MVStore mvStore) {
+        this.queueMap = mvStore.openMap("retained_store");
+    }
+
+    @Override
+    public void cleanRetained(Topic topic) {
+        queueMap.remove(topic);
+    }
+
+    @Override
+    public void retain(Topic topic, MqttPublishMessage msg) {
+        final ByteBuf payload = msg.content();
+        byte[] rawPayload = new byte[payload.readableBytes()];
+        payload.getBytes(0, rawPayload);
+        final RetainedMessage toStore = new RetainedMessage(msg.fixedHeader().qosLevel(), rawPayload);
+        queueMap.put(topic, toStore);
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return queueMap.isEmpty();
+    }
+
+    @Override
+    public List<RetainedMessage> retainedOnTopic(String topic) {
+        final Topic searchTopic = new Topic(topic);
+        final List<RetainedMessage> matchingMessages = new ArrayList<>();
+        for (Map.Entry<Topic, RetainedMessage> entry : queueMap.entrySet()) {
+            final Topic scanTopic = entry.getKey();
+            if (searchTopic.match(scanTopic)) {
+                matchingMessages.add(entry.getValue());
+            }
+        }
+
+        return matchingMessages;
+    }
+}