Adding a couple of utilities (don't alter any existing functionality) that are useful in applications handling failover.

Added example of their use that I've been using in testing.



git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@711256 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 106 insertions, 0 deletions

diff --git a/cpp/examples/failover/resuming_receiver.cpp b/cpp/examples/failover/resuming_receiver.cpp
new file mode 100644
index 0000000000..6ac67d8edb
--- /dev/null
+++ b/cpp/examples/failover/resuming_receiver.cpp
@@ -0,0 +1,106 @@
+/*
+ *
+ * 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 <qpid/client/FailoverManager.h>
+#include <qpid/client/Session.h>
+#include <qpid/client/Message.h>
+#include <qpid/client/SubscriptionManager.h>
+
+#include <iostream>
+#include <fstream>
+
+
+using namespace qpid;
+using namespace qpid::client;
+using namespace qpid::framing;
+
+using namespace std;
+
+
+class Listener : public MessageListener, public FailoverManager::Command
+{
+  public:
+    Listener();
+    void received(Message& message);
+    void execute(AsyncSession& session, bool isRetry);
+  private:
+    Subscription subscription;
+    uint count;
+    uint skipped;
+    uint lastSn;
+};
+
+Listener::Listener() : count(0), skipped(0), lastSn(0) {}
+
+void Listener::received(Message & message) 
+{
+    if (message.getData() == "That's all, folks!") {
+        std::cout << "Shutting down listener for " << message.getDestination()
+                  << std::endl;
+
+        std::cout << "Listener received " << count << " messages (" << skipped << " skipped)" << std::endl;
+        subscription.cancel();
+    } else {
+        uint sn = message.getHeaders().getAsInt("sn");
+        if (lastSn < sn) {
+            if (sn - lastSn > 1) {
+                std::cout << "Warning: gap in sequence between " << lastSn << " and " << sn << std::endl;
+            }
+            lastSn = sn;
+            ++count;
+        } else {
+            ++skipped;
+        }
+    }
+}
+
+void Listener::execute(AsyncSession& session, bool isRetry)
+{
+    if (isRetry) {
+        std::cout << "Resuming from " << count << std::endl;
+    }
+    SubscriptionManager subs(session);
+    subscription = subs.subscribe(*this, "message_queue");
+    subs.run();
+}
+
+int main(int argc, char ** argv)
+{
+    ConnectionSettings settings;
+    if (argc > 1) settings.host = argv[1];
+    if (argc > 2) settings.port = atoi(argv[2]);
+    
+    FailoverManager connection(settings);
+    Listener listener;
+
+    try {
+        connection.execute(listener);
+        connection.close();
+        std::cout << "Completed without error." << std::endl;
+        return 0;
+    } catch(const std::exception& error) {
+        std::cout << "Failure: " << error.what() << std::endl;
+    }
+    return 1;
+}
+
+
+