我有apache's svn的以下代码。如您所见，这是一个异步客户端。我想要的是一个同步客户端，所以客户可以问我的消费者“我能得到一条消息吗”，而我的消费者“肯定，先生，这里是它”。所以我不需要aysnchronous客户端，但我找不到同步的例子，当我编码我得到分段失败一直。
如果查看这段代码，有一个名为onMessage的方法，这是由于监听器，我甚至无法在那里返回消息。无法更改返回类型。
问题是，如何使这个示例类同步，而不会导致分段失败。问题segmentation fails are here.。
/*
* 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 <decaf/lang/Thread.h>
#include <decaf/lang/Runnable.h>
#include <decaf/util/concurrent/CountDownLatch.h>
#include <activemq/core/ActiveMQConnectionFactory.h>
#include <activemq/core/ActiveMQConnection.h>
#include <activemq/transport/DefaultTransportListener.h>
#include <activemq/library/ActiveMQCPP.h>
#include <decaf/lang/Integer.h>
#include <activemq/util/Config.h>
#include <decaf/util/Date.h>
#include <cms/Connection.h>
#include <cms/Session.h>
#include <cms/TextMessage.h>
#include <cms/BytesMessage.h>
#include <cms/MapMessage.h>
#include <cms/ExceptionListener.h>
#include <cms/MessageListener.h>
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
using namespace activemq;
using namespace activemq::core;
using namespace activemq::transport;
using namespace decaf::lang;
using namespace decaf::util;
using namespace decaf::util::concurrent;
using namespace cms;
using namespace std;
////////////////////////////////////////////////////////////////////////////////
class SimpleAsyncConsumer : public ExceptionListener,
public MessageListener,
public DefaultTransportListener {
private:
Connection* connection;
Session* session;
Destination* destination;
MessageConsumer* consumer;
bool useTopic;
std::string brokerURI;
std::string destURI;
bool clientAck;
private:
SimpleAsyncConsumer( const SimpleAsyncConsumer& );
SimpleAsyncConsumer& operator= ( const SimpleAsyncConsumer& );
public:
SimpleAsyncConsumer( const std::string& brokerURI,
const std::string& destURI,
bool useTopic = false,
bool clientAck = false ) :
connection(NULL),
session(NULL),
destination(NULL),
consumer(NULL),
useTopic(useTopic),
brokerURI(brokerURI),
destURI(destURI),
clientAck(clientAck) {
}
virtual ~SimpleAsyncConsumer() throw() {
this->cleanup();
}
void close() {
this->cleanup();
}
void runConsumer() {
try {
// Create a ConnectionFactory
ActiveMQConnectionFactory* connectionFactory =
new ActiveMQConnectionFactory( brokerURI );
// Create a Connection
connection = connectionFactory->createConnection();
delete connectionFactory;
ActiveMQConnection* amqConnection = dynamic_cast<ActiveMQConnection*>( connection );
if( amqConnection != NULL ) {
amqConnection->addTransportListener( this );
}
connection->start();
connection->setExceptionListener(this);
// Create a Session
if( clientAck ) {
session = connection->createSession( Session::CLIENT_ACKNOWLEDGE );
} else {
session = connection->createSession( Session::AUTO_ACKNOWLEDGE );
}
// Create the destination (Topic or Queue)
if( useTopic ) {
destination = session->createTopic( destURI );
} else {
destination = session->createQueue( destURI );
}
// Create a MessageConsumer from the Session to the Topic or Queue
consumer = session->createConsumer( destination );
consumer->setMessageListener( this );
} catch (CMSException& e) {
e.printStackTrace();
}
}
// Called from the consumer since this class is a registered MessageListener.
virtual void onMessage( const Message* message ) throw() {
static int count = 0;
try
{
count++;
const TextMessage* textMessage =
dynamic_cast< const TextMessage* >( message );
string text = "";
if( textMessage != NULL ) {
text = textMessage->getText();
} else {
text = "NOT A TEXTMESSAGE!";
}
if( clientAck ) {
message->acknowledge();
}
printf( "Message #%d Received: %s\n", count, text.c_str() );
} catch (CMSException& e) {
e.printStackTrace();
}
}
// If something bad happens you see it here as this class is also been
// registered as an ExceptionListener with the connection.
virtual void onException( const CMSException& ex AMQCPP_UNUSED ) {
printf("CMS Exception occurred. Shutting down client.\n");
exit(1);
}
virtual void transportInterrupted() {
std::cout << "The Connection's Transport has been Interrupted." << std::endl;
}
virtual void transportResumed() {
std::cout << "The Connection's Transport has been Restored." << std::endl;
}
private:
void cleanup(){
//*************************************************
// Always close destination, consumers and producers before
// you destroy their sessions and connection.
//*************************************************
// Destroy resources.
try{
if( destination != NULL ) delete destination;
}catch (CMSException& e) {}
destination = NULL;
try{
if( consumer != NULL ) delete consumer;
}catch (CMSException& e) {}
consumer = NULL;
// Close open resources.
try{
if( session != NULL ) session->close();
if( connection != NULL ) connection->close();
}catch (CMSException& e) {}
// Now Destroy them
try{
if( session != NULL ) delete session;
}catch (CMSException& e) {}
session = NULL;
try{
if( connection != NULL ) delete connection;
}catch (CMSException& e) {}
connection = NULL;
}
};
////////////////////////////////////////////////////////////////////////////////
int main(int argc AMQCPP_UNUSED, char* argv[] AMQCPP_UNUSED) {
activemq::library::ActiveMQCPP::initializeLibrary();
std::cout << "=====================================================\n";
std::cout << "Starting the example:" << std::endl;
std::cout << "-----------------------------------------------------\n";
// Set the URI to point to the IPAddress of your broker.
// add any optional params to the url to enable things like
// tightMarshalling or tcp logging etc. See the CMS web site for
// a full list of configuration options.
//
// http://activemq.apache.org/cms/
//
// Wire Format Options:
// =====================
// Use either stomp or openwire, the default ports are different for each
//
// Examples:
// tcp://127.0.0.1:61616 default to openwire
// tcp://127.0.0.1:61616?wireFormat=openwire same as above
// tcp://127.0.0.1:61613?wireFormat=stomp use stomp instead
//
std::string brokerURI =
"failover:(tcp://127.0.0.1:61616"
// "?wireFormat=openwire"
// "&connection.useAsyncSend=true"
// "&transport.commandTracingEnabled=true"
// "&transport.tcpTracingEnabled=true"
// "&wireFormat.tightEncodingEnabled=true"
")";
//============================================================
// This is the Destination Name and URI options. Use this to
// customize where the consumer listens, to have the consumer
// use a topic or queue set the 'useTopics' flag.
//============================================================
std::string destURI = "TEST.FOO"; //?consumer.prefetchSize=1";
//============================================================
// set to true to use topics instead of queues
// Note in the code above that this causes createTopic or
// createQueue to be used in the consumer.
//============================================================
bool useTopics = false;
//============================================================
// set to true if you want the consumer to use client ack mode
// instead of the default auto ack mode.
//============================================================
bool clientAck = false;
// Create the consumer
SimpleAsyncConsumer consumer( brokerURI, destURI, useTopics, clientAck );
// Start it up and it will listen forever.
consumer.runConsumer();
// Wait to exit.
std::cout << "Press 'q' to quit" << std::endl;
while( std::cin.get() != 'q') {}
// All CMS resources should be closed before the library is shutdown.
consumer.close();
std::cout << "-----------------------------------------------------\n";
std::cout << "Finished with the example." << std::endl;
std::cout << "=====================================================\n";
activemq::library::ActiveMQCPP::shutdownLibrary();
}
答案 0 :(得分：1)
根据您之前的问题，我看到您找到了MessageConsumer的receive（）功能，这是创建同步接收器的方法。我不知道为什么你会得到分段错误。我可以为此提出几点建议：
尝试设置一个clientID，不确定SessionExecutor上的第129行是否是罪魁祸首，但是它正在尝试访问那里的消费者ID，并且可能是stomp客户端没有设置。
std::string clientID = "someid";
Connection* conn = connectionFactory->createConnection("", "", clientID);
尝试切换到openwire协议而不是stomp。
如果从该代码中取出接收部分，它是否连接到代理？ 对不起，如果这不能完全回答你的问题，我正试图缩小问题的范围。