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ActiveMQ example source code file (MasterBroker.java)

This example ActiveMQ source code file (MasterBroker.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - ActiveMQ tags/keywords

consumerid, exception, exception, failed, failed, masterbroker, override, producerinfo, slave, threading, threads, throwable, transactionid, transactionid, transactioninfo, transactioninfo, util

The ActiveMQ MasterBroker.java source code

/**
 * 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.activemq.broker.ft;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicBoolean;

import org.apache.activemq.broker.Connection;
import org.apache.activemq.broker.ConnectionContext;
import org.apache.activemq.broker.ConsumerBrokerExchange;
import org.apache.activemq.broker.InsertableMutableBrokerFilter;
import org.apache.activemq.broker.MutableBrokerFilter;
import org.apache.activemq.broker.ProducerBrokerExchange;
import org.apache.activemq.broker.region.Subscription;
import org.apache.activemq.command.Command;
import org.apache.activemq.command.ConnectionControl;
import org.apache.activemq.command.ConnectionInfo;
import org.apache.activemq.command.ConsumerId;
import org.apache.activemq.command.ConsumerInfo;
import org.apache.activemq.command.DestinationInfo;
import org.apache.activemq.command.ExceptionResponse;
import org.apache.activemq.command.Message;
import org.apache.activemq.command.MessageAck;
import org.apache.activemq.command.MessageDispatch;
import org.apache.activemq.command.MessageDispatchNotification;
import org.apache.activemq.command.ProducerInfo;
import org.apache.activemq.command.RemoveInfo;
import org.apache.activemq.command.RemoveSubscriptionInfo;
import org.apache.activemq.command.Response;
import org.apache.activemq.command.SessionInfo;
import org.apache.activemq.command.TransactionId;
import org.apache.activemq.command.TransactionInfo;
import org.apache.activemq.transport.MutexTransport;
import org.apache.activemq.transport.ResponseCorrelator;
import org.apache.activemq.transport.Transport;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The Message Broker which passes messages to a slave
 * 
 * 
 */
public class MasterBroker extends InsertableMutableBrokerFilter {

    private static final Logger LOG = LoggerFactory.getLogger(MasterBroker.class);
    private Transport slave;
    private AtomicBoolean started = new AtomicBoolean(false);

    private Map<ConsumerId, ConsumerId> consumers = new ConcurrentHashMap();
    
    /**
     * Constructor
     * 
     * @param parent
     * @param transport
     */
    public MasterBroker(MutableBrokerFilter parent, Transport transport) {
        super(parent);
        this.slave = transport;
        this.slave = new MutexTransport(slave);
        this.slave = new ResponseCorrelator(slave);
        this.slave.setTransportListener(transport.getTransportListener());
    }

    /**
     * start processing this broker
     */
    public void startProcessing() {
        started.set(true);
        try {
            Connection[] connections = getClients();
            ConnectionControl command = new ConnectionControl();
            command.setFaultTolerant(true);
            if (connections != null) {
                for (int i = 0; i < connections.length; i++) {
                    if (connections[i].isActive() && connections[i].isManageable()) {
                        connections[i].dispatchAsync(command);
                    }
                }
            }
        } catch (Exception e) {
            LOG.error("Failed to get Connections", e);
        }
    }

    /**
     * stop the broker
     * 
     * @throws Exception
     */
    public void stop() throws Exception {
        stopProcessing();
    }

    /**
     * stop processing this broker
     */
    public void stopProcessing() {
        if (started.compareAndSet(true, false)) {
            remove();
        }
    }

    /**
     * A client is establishing a connection with the broker.
     * 
     * @param context
     * @param info
     * @throws Exception
     */
    public void addConnection(ConnectionContext context, ConnectionInfo info) throws Exception {
        super.addConnection(context, info);
        sendAsyncToSlave(info);
    }

    /**
     * A client is disconnecting from the broker.
     * 
     * @param context the environment the operation is being executed under.
     * @param info
     * @param error null if the client requested the disconnect or the error
     *                that caused the client to disconnect.
     * @throws Exception
     */
    public void removeConnection(ConnectionContext context, ConnectionInfo info, Throwable error) throws Exception {
        super.removeConnection(context, info, error);
        sendAsyncToSlave(new RemoveInfo(info.getConnectionId()));
    }

    /**
     * Adds a session.
     * 
     * @param context
     * @param info
     * @throws Exception
     */
    public void addSession(ConnectionContext context, SessionInfo info) throws Exception {
        super.addSession(context, info);
        sendAsyncToSlave(info);
    }

    /**
     * Removes a session.
     * 
     * @param context
     * @param info
     * @throws Exception
     */
    public void removeSession(ConnectionContext context, SessionInfo info) throws Exception {
        super.removeSession(context, info);
        sendAsyncToSlave(new RemoveInfo(info.getSessionId()));
    }

    /**
     * Adds a producer.
     * 
     * @param context the enviorment the operation is being executed under.
     * @param info
     * @throws Exception
     */
    public void addProducer(ConnectionContext context, ProducerInfo info) throws Exception {
        super.addProducer(context, info);
        sendAsyncToSlave(info);
    }

    /**
     * Removes a producer.
     * 
     * @param context the environment the operation is being executed under.
     * @param info
     * @throws Exception
     */
    public void removeProducer(ConnectionContext context, ProducerInfo info) throws Exception {
        super.removeProducer(context, info);
        sendAsyncToSlave(new RemoveInfo(info.getProducerId()));
    }

    /**
     * add a consumer
     * 
     * @param context
     * @param info
     * @return the associated subscription
     * @throws Exception
     */
    public Subscription addConsumer(ConnectionContext context, ConsumerInfo info) throws Exception {
        sendSyncToSlave(info);
        consumers.put(info.getConsumerId(), info.getConsumerId());
        return super.addConsumer(context, info);
    }

    @Override
    public void removeConsumer(ConnectionContext context, ConsumerInfo info)
            throws Exception {
        super.removeConsumer(context, info);
        consumers.remove(info.getConsumerId());
        sendSyncToSlave(new RemoveInfo(info.getConsumerId()));
   }

    /**
     * remove a subscription
     * 
     * @param context
     * @param info
     * @throws Exception
     */
    public void removeSubscription(ConnectionContext context, RemoveSubscriptionInfo info) throws Exception {
        super.removeSubscription(context, info);
        sendAsyncToSlave(info);
    }
    
    @Override
    public void addDestinationInfo(ConnectionContext context,
            DestinationInfo info) throws Exception {
        super.addDestinationInfo(context, info);
        if (info.getDestination().isTemporary()) {
            sendAsyncToSlave(info);
        }
    }

    @Override
    public void removeDestinationInfo(ConnectionContext context, DestinationInfo info) throws Exception {
        super.removeDestinationInfo(context, info);
        if (info.getDestination().isTemporary()) {
            sendAsyncToSlave(info);
        }
    }
    
    /**
     * begin a transaction
     * 
     * @param context
     * @param xid
     * @throws Exception
     */
    public void beginTransaction(ConnectionContext context, TransactionId xid) throws Exception {
        TransactionInfo info = new TransactionInfo(context.getConnectionId(), xid, TransactionInfo.BEGIN);
        sendAsyncToSlave(info);
        super.beginTransaction(context, xid);
    }

    /**
     * Prepares a transaction. Only valid for xa transactions.
     * 
     * @param context
     * @param xid
     * @return the state
     * @throws Exception
     */
    public int prepareTransaction(ConnectionContext context, TransactionId xid) throws Exception {
        TransactionInfo info = new TransactionInfo(context.getConnectionId(), xid, TransactionInfo.PREPARE);
        sendSyncToSlave(info);
        int result = super.prepareTransaction(context, xid);
        return result;
    }

    /**
     * Rollsback a transaction.
     * 
     * @param context
     * @param xid
     * @throws Exception
     */
    public void rollbackTransaction(ConnectionContext context, TransactionId xid) throws Exception {
        TransactionInfo info = new TransactionInfo(context.getConnectionId(), xid, TransactionInfo.ROLLBACK);
        sendAsyncToSlave(info);
        super.rollbackTransaction(context, xid);
    }

    /**
     * Commits a transaction.
     * 
     * @param context
     * @param xid
     * @param onePhase
     * @throws Exception
     */
    public void commitTransaction(ConnectionContext context, TransactionId xid, boolean onePhase) throws Exception {
        TransactionInfo info = new TransactionInfo(context.getConnectionId(), xid, TransactionInfo.COMMIT_ONE_PHASE);
        sendSyncToSlave(info);
        super.commitTransaction(context, xid, onePhase);
    }

    /**
     * Forgets a transaction.
     * 
     * @param context
     * @param xid
     * @throws Exception
     */
    public void forgetTransaction(ConnectionContext context, TransactionId xid) throws Exception {
        TransactionInfo info = new TransactionInfo(context.getConnectionId(), xid, TransactionInfo.FORGET);
        sendAsyncToSlave(info);
        super.forgetTransaction(context, xid);
    }

    /**
     * Notifiy the Broker that a dispatch will happen
     * Do in 'pre' so that slave will avoid getting ack before dispatch
     * similar logic to send() below.
     * @param messageDispatch
     */
    public void preProcessDispatch(MessageDispatch messageDispatch) {
        super.preProcessDispatch(messageDispatch);
        MessageDispatchNotification mdn = new MessageDispatchNotification();
        mdn.setConsumerId(messageDispatch.getConsumerId());
        mdn.setDeliverySequenceId(messageDispatch.getDeliverySequenceId());
        mdn.setDestination(messageDispatch.getDestination());
        if (messageDispatch.getMessage() != null) {
            Message msg = messageDispatch.getMessage();
            mdn.setMessageId(msg.getMessageId());
            if (consumers.containsKey(messageDispatch.getConsumerId())) {
                sendSyncToSlave(mdn);
            }
        }
    }

    /**
     * @param context
     * @param message
     * @throws Exception
     */
    public void send(ProducerBrokerExchange producerExchange, Message message) throws Exception {
        /**
         * A message can be dispatched before the super.send() method returns so -
         * here the order is switched to avoid problems on the slave with
         * receiving acks for messages not received yet
         * copy ensures we don't mess with the correlator and command ids
         */
        sendSyncToSlave(message.copy());
        super.send(producerExchange, message);
    }

    /**
     * @param context
     * @param ack
     * @throws Exception
     */
    public void acknowledge(ConsumerBrokerExchange consumerExchange, MessageAck ack) throws Exception {
        sendToSlave(ack);
        super.acknowledge(consumerExchange, ack);
    }

    public boolean isFaultTolerantConfiguration() {
        return true;
    }

    protected void sendToSlave(Message message) {
        if (message.isResponseRequired()) {
            sendSyncToSlave(message);
        } else {
            sendAsyncToSlave(message);
        }
    }

    protected void sendToSlave(MessageAck ack) {
        if (ack.isResponseRequired()) {
            sendAsyncToSlave(ack);
        } else {
            sendSyncToSlave(ack);
        }
    }

    protected void sendAsyncToSlave(Command command) {
        try {
            slave.oneway(command);
        } catch (Throwable e) {
            LOG.error("Slave Failed", e);
            stopProcessing();
        }
    }

    protected void sendSyncToSlave(Command command) {
        try {
            Response response = (Response)slave.request(command);
            if (response.isException()) {
                ExceptionResponse er = (ExceptionResponse)response;
                LOG.error("Slave Failed", er.getException());
            }
        } catch (Throwable e) {
            LOG.error("Slave Failed", e);
        }
    }
}

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