MQPullConsumer.java

/**
 * Copyright (C) 2010-2013 Alibaba Group Holding Limited
 *
 * Licensed 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 com.alibaba.rocketmq.client.consumer;

import java.util.Set;

import com.alibaba.rocketmq.client.exception.MQBrokerException;
import com.alibaba.rocketmq.client.exception.MQClientException;
import com.alibaba.rocketmq.common.message.MessageQueue;
import com.alibaba.rocketmq.remoting.exception.RemotingException;


/**
 * 消费者，主动方式消费
 * 
 * @author shijia.wxr<vintage.wang@gmail.com>
 * @since 2013-7-24
 */
public interface MQPullConsumer extends MQConsumer {
    /**
     * 启动服务
     * 
     * @throws MQClientException
     */
    public void start() throws MQClientException;


    /**
     * 关闭服务
     */
    public void shutdown();


    /**
     * 注册监听队列变化的listener对象
     * 
     * @param topic
     * @param listener
     *            一旦发生变化，客户端会主动回调listener对象
     */
    public void registerMessageQueueListener(final String topic, final MessageQueueListener listener);


    /**
     * 指定队列，主动拉取消息，即使没有消息，也立刻返回
     * 
     * @param mq
     *            指定具体要拉取的队列
     * @param subExpression
     *            订阅过滤表达式字符串，broker依据此表达式进行过滤。目前只支持或运算<br>
     *            eg: "tag1 || tag2 || tag3"<br>
     *            如果subExpression等于null或者*，则表示全部订阅
     * @param offset
     *            从指定队列哪个位置开始拉取
     * @param maxNums
     *            一次最多拉取条数
     * @return 参见PullResult
     * @throws MQClientException
     * @throws InterruptedException
     * @throws MQBrokerException
     * @throws RemotingException
     */
    public PullResult pull(final MessageQueue mq, final String subExpression, final long offset,
            final int maxNums) throws MQClientException, RemotingException, MQBrokerException,
            InterruptedException;


    public void pull(final MessageQueue mq, final String subExpression, final long offset, final int maxNums,
            final PullCallback pullCallback) throws MQClientException, RemotingException,
            InterruptedException;


    /**
     * 指定队列，主动拉取消息，如果没有消息，则broker阻塞一段时间再返回（时间可配置）<br>
     * broker阻塞期间，如果有消息，则立刻将消息返回
     * 
     * @param mq
     *            指定具体要拉取的队列
     * @param subExpression
     *            订阅过滤表达式字符串，broker依据此表达式进行过滤。目前只支持或运算<br>
     *            eg: "tag1 || tag2 || tag3"<br>
     *            如果subExpression等于null或者*，则表示全部订阅
     * @param offset
     *            从指定队列哪个位置开始拉取
     * @param maxNums
     *            一次最多拉取条数
     * @return 参见PullResult
     * @throws InterruptedException
     * @throws MQBrokerException
     * @throws RemotingException
     * @throws MQClientException
     */
    public PullResult pullBlockIfNotFound(final MessageQueue mq, final String subExpression,
            final long offset, final int maxNums) throws MQClientException, RemotingException,
            MQBrokerException, InterruptedException;


    public void pullBlockIfNotFound(final MessageQueue mq, final String subExpression, final long offset,
            final int maxNums, final PullCallback pullCallback) throws MQClientException, RemotingException,
            InterruptedException;


    /**
     * 更新消费进度<br>
     * 只是更新Consumer缓存中的数据，如果是广播模式，则定时更新到本地存储<br>
     * 如果是集群模式，则定时更新到远端Broker<br>
     * <p/>
     * P.S. 可频繁调用，无性能开销
     * 
     * @param mq
     * @param offset
     * @throws MQClientException
     */
    public void updateConsumeOffset(final MessageQueue mq, final long offset) throws MQClientException;


    /**
     * 获取消费进度，返回-1表示出错
     * 
     * @param mq
     * @param fromStore
     * @return
     * @throws MQClientException
     */
    public long fetchConsumeOffset(final MessageQueue mq, final boolean fromStore) throws MQClientException;


    /**
     * 根据topic获取MessageQueue，以均衡方式在组内多个成员之间分配
     * 
     * @param topic
     *            消息Topic
     * @return 返回队列集合
     * @throws MQClientException
     */
    public Set<MessageQueue> fetchMessageQueuesInBalance(final String topic) throws MQClientException;
}