1 files changed, 73 insertions, 0 deletions
diff --git a/java/broker-core/src/main/java/org/apache/qpid/server/consumer/AbstractConsumerTarget.java b/java/broker-core/src/main/java/org/apache/qpid/server/consumer/AbstractConsumerTarget.java
new file mode 100644
index 0000000000..aa721e598a
--- /dev/null
+++ b/java/broker-core/src/main/java/org/apache/qpid/server/consumer/AbstractConsumerTarget.java
@@ -0,0 +1,73 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ *
+ */
+package org.apache.qpid.server.consumer;
+
+import org.apache.qpid.server.util.StateChangeListener;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+public abstract class AbstractConsumerTarget implements ConsumerTarget
+{
+
+    private final AtomicReference<State> _state;
+    private final AtomicReference<StateChangeListener<ConsumerTarget, State>> _stateListener =
+            new AtomicReference<StateChangeListener<ConsumerTarget, State>>();
+
+    protected AbstractConsumerTarget(final State initialState)
+    {
+        _state = new AtomicReference<State>(initialState);
+    }
+
+
+    public final State getState()
+    {
+        return _state.get();
+    }
+
+    protected final boolean updateState(State from, State to)
+    {
+        if(_state.compareAndSet(from, to))
+        {
+            StateChangeListener<ConsumerTarget, State> listener = _stateListener.get();
+            if(listener != null)
+            {
+                listener.stateChanged(this, from, to);
+            }
+            return true;
+        }
+        else
+        {
+            return false;
+        }
+    }
+
+
+    public final void setStateListener(StateChangeListener<ConsumerTarget, State> listener)
+    {
+        _stateListener.set(listener);
+    }
+
+    public final StateChangeListener<ConsumerTarget, State> getStateListener()
+    {
+        return _stateListener.get();
+    }
+
+}