Removed the constraint on client queues to be BlockingQueue but simple Queue

h2_storage/src/main/java/io/moquette/persistence/h2/H2PersistentQueue.java

@@ -9,7 +9,7 @@ import java.util.concurrent.atomic.AtomicLong;
 
 class H2PersistentQueue<T> extends AbstractQueue<T> {
 
-    private final MVMap<Long, T> mvMap;
+    private final MVMap<Long, T> queueMap;
     private final MVMap<String, Long> metadataMap;
     private final AtomicLong head;
     private final AtomicLong tail;
@@ -18,7 +18,7 @@ class H2PersistentQueue<T> extends AbstractQueue<T> {
         if (queueName == null || queueName.isEmpty()) {
             throw new IllegalArgumentException("queueName parameter can't be empty or null");
         }
-        this.mvMap = store.openMap("queue_" + queueName);
+        this.queueMap = store.openMap("queue_" + queueName);
         this.metadataMap = store.openMap("queue_" + queueName + "_meta");
 
         //setup head index
@@ -40,6 +40,11 @@ class H2PersistentQueue<T> extends AbstractQueue<T> {
         this.tail = new AtomicLong(tailIdx);
     }
 
+    static void dropQueue(MVStore store, String queueName) {
+        store.removeMap(store.openMap("queue_" + queueName));
+        store.removeMap(store.openMap("queue_" + queueName + "_meta"));
+    }
+
     @Override
     public Iterator<T> iterator() {
         return null;
@@ -56,7 +61,7 @@ class H2PersistentQueue<T> extends AbstractQueue<T> {
             throw new NullPointerException("Inserted element can't be null");
         }
         final long nextHead = head.getAndIncrement();
-        this.mvMap.put(nextHead, t);
+        this.queueMap.put(nextHead, t);
         this.metadataMap.put("head", nextHead + 1);
         return true;
     }
@@ -67,7 +72,7 @@ class H2PersistentQueue<T> extends AbstractQueue<T> {
             return null;
         }
         final long nextTail = tail.getAndIncrement();
-        final T tail = this.mvMap.get(nextTail);
+        final T tail = this.queueMap.get(nextTail);
         this.metadataMap.put("tail", nextTail + 1);
         return tail;
     }
@@ -77,7 +82,7 @@ class H2PersistentQueue<T> extends AbstractQueue<T> {
         if (head.equals(tail)) {
             return null;
         }
-        return this.mvMap.get(tail.get());
+        return this.queueMap.get(tail.get());
     }
 
 }

h2_storage/src/main/java/io/moquette/persistence/h2/H2SessionsStore.java

@@ -23,14 +23,12 @@ import io.moquette.spi.ISessionsStore;
 import io.moquette.spi.ISubscriptionsStore;
 import io.moquette.spi.impl.subscriptions.Subscription;
 import io.moquette.spi.impl.subscriptions.Topic;
-import org.h2.mvstore.Cursor;
 import org.h2.mvstore.MVMap;
 import org.h2.mvstore.MVStore;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.*;
-import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 
@@ -219,7 +217,7 @@ public class H2SessionsStore implements ISessionsStore, ISubscriptionsStore {
         Set<Integer> inFlightForClient = this.inFlightIds.get(clientID);
         if (inFlightForClient == null) {
             int nextPacketId = 1;
-            inFlightForClient = Collections.newSetFromMap(new ConcurrentHashMap<Integer, Boolean>());
+            inFlightForClient = Collections.newSetFromMap(new ConcurrentHashMap<>());
             inFlightForClient.add(nextPacketId);
             this.inFlightIds.put(clientID, inFlightForClient);
             return nextPacketId;
@@ -232,53 +230,14 @@ public class H2SessionsStore implements ISessionsStore, ISubscriptionsStore {
         return nextPacketId;
     }
 
-
-    class H2BackedQueue<T> extends AbstractQueue<T> {
-
-        private final MVMap<T, ?> map;
-        private final Cursor<T, ?> cursor;
-
-        H2BackedQueue(MVMap<T, ?> map) {
-            this.cursor = map.cursor(null);
-            this.map = map;
-        }
-
-        @Override
-        public Iterator<T> iterator() {
-            return cursor;
-        }
-
-        @Override
-        public int size() {
-            return map.size();
-        }
-
-        @Override
-        public boolean offer(T t) {
-            return false;
-        }
-
-        @Override
-        public T poll() {
-            return null;
-        }
-
-        @Override
-        public T peek() {
-            return null;
-        }
-    }
-
-    //TODO
     @Override
-    public BlockingQueue<StoredMessage> queue(String clientID) {
-        throw new RuntimeException("Not yet implemented");
+    public Queue<StoredMessage> queue(String clientID) {
+        return new H2PersistentQueue<>(this.mvStore, clientID);
     }
 
-    //TODO
     @Override
     public void dropQueue(String clientID) {
-        throw new RuntimeException("Not yet implemented");
+        H2PersistentQueue.dropQueue(this.mvStore, clientID);
     }
 
     @Override