com.alibaba.dubbo.rpc.cluster.support.ForkingClusterInvoker Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of dubbo2 Show documentation
The all in one project of dubbo2
The newest version!
/*
 * Copyright 1999-2011 Alibaba Group.
 *  
 * 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.dubbo.rpc.cluster.support;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import com.alibaba.dubbo.common.Constants;
import com.alibaba.dubbo.common.utils.NamedThreadFactory;
import com.alibaba.dubbo.rpc.Invocation;
import com.alibaba.dubbo.rpc.Invoker;
import com.alibaba.dubbo.rpc.Result;
import com.alibaba.dubbo.rpc.RpcContext;
import com.alibaba.dubbo.rpc.RpcException;
import com.alibaba.dubbo.rpc.cluster.Directory;
import com.alibaba.dubbo.rpc.cluster.LoadBalance;

/**
 * 并行调用，只要一个成功即返回，通常用于实时性要求较高的操作，但需要浪费更多服务资源。
 * 
 * Fork
 * 
 * @author william.liangf
 */
public class ForkingClusterInvoker extends AbstractClusterInvoker{

    private final ExecutorService executor = Executors.newCachedThreadPool(new NamedThreadFactory("forking-cluster-timer", true)); 

    public ForkingClusterInvoker(Directory directory) {
        super(directory);
    }

    @SuppressWarnings({ "unchecked", "rawtypes" })
    public Result doInvoke(final Invocation invocation, List> invokers, LoadBalance loadbalance) throws RpcException {
        checkInvokers(invokers, invocation);
        final List> selected;
        final int forks = getUrl().getParameter(Constants.FORKS_KEY, Constants.DEFAULT_FORKS);
        final int timeout = getUrl().getParameter(Constants.TIMEOUT_KEY, Constants.DEFAULT_TIMEOUT);
        if (forks <= 0 || forks >= invokers.size()) {
            selected = invokers;
        } else {
            selected = new ArrayList>();
            for (int i = 0; i < forks; i++) {
                //在invoker列表(排除selected)后,如果没有选够,则存在重复循环问题.见select实现.
                Invoker invoker = select(loadbalance, invocation, invokers, selected);
                if(!selected.contains(invoker)){//防止重复添加invoker
                    selected.add(invoker);
                }
            }
        }
        RpcContext.getContext().setInvokers((List)selected);
        final AtomicInteger count = new AtomicInteger();
        final BlockingQueue