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Diffstat (limited to 'qpid/cpp/examples/examples/pub-sub/topic_listener.cpp')
-rw-r--r-- | qpid/cpp/examples/examples/pub-sub/topic_listener.cpp | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/qpid/cpp/examples/examples/pub-sub/topic_listener.cpp b/qpid/cpp/examples/examples/pub-sub/topic_listener.cpp new file mode 100644 index 0000000000..e5292db703 --- /dev/null +++ b/qpid/cpp/examples/examples/pub-sub/topic_listener.cpp @@ -0,0 +1,175 @@ +/* + * + * 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. + * + */ + +/** + * topic_listener.cpp: + * + * This program is one of three programs designed to be used + * together. These programs use the topic exchange. + * + * topic_config_queues.cpp: + * + * Creates a queue on a broker, binding a routing key to route + * messages to that queue. + * + * topic_publisher.cpp: + * + * Publishes to a broker, specifying a routing key. + * + * topic_listener.cpp (this program): + * + * Reads from a queue on the broker using a message listener. + * + */ + +#include <qpid/client/Connection.h> +#include <qpid/client/Session.h> +#include <qpid/client/Message.h> +#include <qpid/client/MessageListener.h> +#include <qpid/client/Queue.h> +#include <qpid/client/SubscriptionManager.h> + +#include <unistd.h> +#include <cstdlib> +#include <iostream> +#include <set> + +using namespace qpid::client; +using namespace qpid::framing; + + +class Listener : public MessageListener { + private: + Session& session; + SubscriptionManager subscriptions; + public: + Listener(Session& session); + virtual void prepareQueue(std::string queue, std::string routing_key); + virtual void received(Message& message); + virtual void listen(); + ~Listener() { }; +}; + + +/* + * Listener::Listener + * + * Subscribe to the queue, route it to a client destination for the + * listener. (The destination name merely identifies the destination + * in the listener, you can use any name as long as you use the same + * name for the listener). + */ + +Listener::Listener(Session& session) : + session(session), + subscriptions(session) +{ +} + + +void Listener::prepareQueue(std::string queue, std::string routing_key) { + + /* Create a unique queue name for this consumer by concatenating + * the queue name parameter with the Session ID. + */ + + queue += session.getId().str(); + std::cout << "Declaring queue: " << queue << std::endl; + + /* Declare an exclusive queue on the broker + */ + + session.queueDeclare(arg::queue=queue, arg::exclusive=true); + + /* Route messages to the new queue if they match the routing key. + * + * Also route any messages to with the "control" routing key to + * this queue so we know when it's time to stop. A publisher sends + * a message with the content "That's all, Folks!", using the + * "control" routing key, when it is finished. + */ + + session.queueBind(arg::exchange="amq.topic", arg::queue=queue, arg::routingKey=routing_key); + session.queueBind(arg::exchange="amq.topic", arg::queue=queue, arg::routingKey="control"); + + /* + * subscribe to the queue using the subscription manager. + */ + + std::cout << "Subscribing to queue " << queue << std::endl; + subscriptions.subscribe(*this, queue); +} + +void Listener::received(Message& message) { + std::cout << "Message: " << message.getData() << " from " << message.getDestination() << std::endl; + + if (message.getData() == "That's all, folks!") { + std::cout << "Shutting down listener for " << message.getDestination() << std::endl; + subscriptions.cancel(message.getDestination()); + } +} + +void Listener::listen() { + // Receive messages + subscriptions.run(); +} + +int main(int argc, char** argv) { + const char* host = argc>1 ? argv[1] : "127.0.0.1"; + int port = argc>2 ? atoi(argv[2]) : 5672; + Connection connection; + try { + connection.open(host, port); + Session session = connection.newSession(ASYNC); + + //--------- Main body of program -------------------------------------------- + + // Create a listener for the session + + Listener listener(session); + + // Subscribe to messages on the queues we are interested in + + listener.prepareQueue("usa", "usa.#"); + listener.prepareQueue("europe", "europe.#"); + listener.prepareQueue("news", "#.news"); + listener.prepareQueue("weather", "#.weather"); + + // Wait for the broker to indicate that our queues have been created. + session.sync(); + + std::cout << "Listening for messages ..." << std::endl; + + // Give up control and receive messages + listener.listen(); + + + //----------------------------------------------------------------------------- + + connection.close(); + return 0; + } catch(const std::exception& error) { + std::cout << error.what() << std::endl; + } + return 1; +} + + |