QPID-1567: Initial support for asynchronous queue state replication

* Added QueueEvents class with per broker instance
* Modified qpid::broker::Queue to notify QueueEvents of enqueues and dequeues (based on configuration)
* Added replication subdir containing two plugins:
  - an event listener that registers with QueueEvents and creates messages representing received 
    events on a replication queue
  - a custom exchange type for processing messages of the format created by the listener plugin
* Added new option for controlling event generation to qpid::client::QueueOptions
* Added new queue option to qpid-config script for the same



git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk/qpid@734674 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 77 insertions, 0 deletions

diff --git a/cpp/src/qpid/broker/QueueEvents.h b/cpp/src/qpid/broker/QueueEvents.h
new file mode 100644
index 0000000000..2ba69e33e6
--- /dev/null
+++ b/cpp/src/qpid/broker/QueueEvents.h
@@ -0,0 +1,77 @@
+#ifndef QPID_BROKER_QUEUEEVENTS_H
+#define QPID_BROKER_QUEUEEVENTS_H
+
+/*
+ *
+ * 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.
+ *
+ */
+
+#include "QueuedMessage.h"
+#include "qpid/sys/Mutex.h"
+#include "qpid/sys/PollableQueue.h"
+#include <map>
+#include <string>
+#include <boost/function.hpp>
+
+namespace qpid {
+namespace broker {
+
+/**
+ * Event manager for queue events. Allows queues to indicate when
+ * events have occured; allows listeners to register for notification
+ * of this. The notification happens asynchronously, in a separate
+ * thread.
+ */
+class QueueEvents
+{
+  public:
+    enum EventType {ENQUEUE, DEQUEUE};
+
+    struct Event
+    {
+        EventType type;
+        QueuedMessage msg;
+
+        Event(EventType, const QueuedMessage&);
+    };
+
+    typedef boost::function<void (Event)> EventListener;
+
+    QueueEvents(const boost::shared_ptr<sys::Poller>& poller);
+    ~QueueEvents();
+    void enqueued(const QueuedMessage&);
+    void dequeued(const QueuedMessage&);
+    void registerListener(const std::string& id, const EventListener&);
+    void unregisterListener(const std::string& id);
+    //process all outstanding events
+    void shutdown();
+  private:
+    typedef qpid::sys::PollableQueue<Event> EventQueue;
+    typedef std::map<std::string, EventListener> Listeners;
+
+    EventQueue eventQueue;
+    Listeners listeners;
+    qpid::sys::Mutex lock;//protect listeners from concurrent access
+    
+    void handle(EventQueue::Queue& e);
+
+};
+}} // namespace qpid::broker
+
+#endif  /*!QPID_BROKER_QUEUEEVENTS_H*/