AllocateMessageQueueAveragely.java

/**
 * $Id: AllocateMessageQueueAveragely.java 1831 2013-05-16 01:39:51Z shijia.wxr $
 */
package com.alibaba.rocketmq.client.consumer.loadbalance;

import java.util.ArrayList;
import java.util.List;

import com.alibaba.rocketmq.client.consumer.AllocateMessageQueueStrategy;
import com.alibaba.rocketmq.common.MessageQueue;


/**
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 * 
 * @author vintage.wang@gmail.com shijia.wxr@taobao.com
 * 
 */
public class AllocateMessageQueueAveragely implements AllocateMessageQueueStrategy {
    @Override
    public List<MessageQueue> allocate(String group, String topic, String currentCID, List<MessageQueue> mqAll,
            List<String> cidAll) {
        List<MessageQueue> result = new ArrayList<MessageQueue>();
        int currentIndex = cidAll.indexOf(currentCID);
        if (currentIndex < 0) {
            return result;
        }

        int mod = mqAll.size() / cidAll.size();
        int rem = mqAll.size() % cidAll.size();
        int startindex = mod * currentIndex;
        int endindex = startindex + mod;
        for (int i = startindex; i < endindex; i++) {
            result.add(mqAll.get(i));
        }
        if (rem > currentIndex) {
            result.add(mqAll.get(currentIndex + mod * cidAll.size()));
        }
        return result;
    }
}