多线程

/**
 * Project: aliwork.web
 * 
 * File Created at 2014-10-15
 * $Id$
 * 
 * Copyright 2008 Alibaba.com Corporation Limited.
 * All rights reserved.
 *
 * This software is the confidential and proprietary information of
 * Alibaba Company. ("Confidential Information").  You shall not
 * disclose such Confidential Information and shall use it only in
 * accordance with the terms of the license agreement you entered into
 * with Alibaba.com.
 */
package com.alibaba.aliwork.web.listener;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import javax.servlet.ServletContext;

import org.springframework.web.context.ContextLoader;
import org.springframework.web.context.ContextLoaderListener;

import com.alibaba.citrus.webx.WebxComponent;
import com.alibaba.citrus.webx.WebxController;
import com.alibaba.citrus.webx.context.WebxComponentContext;
import com.alibaba.citrus.webx.context.WebxComponentsContext;
import com.alibaba.citrus.webx.context.WebxComponentsLoader;

/**
 * 在原有WebxContextLoaderListener的基础上做了加速<br>
 * 使用多线程加载components，启动速度大幅度提升<br>
 * components越多，速度提升越明显<br>
 * 
 * @author xiaoxiaosir.chenxg 2014-10-15
 */
public class WebxFastContextLoaderListener extends ContextLoaderListener {
    @Override
    protected final ContextLoader createContextLoader() {
        return new WebxComponentsLoader() {

            @Override
            protected Class<? extends WebxComponentsContext> getDefaultContextClass() {
                Class<? extends WebxComponentsContext> defaultContextClass = WebxFastContextLoaderListener.this
                        .getDefaultContextClass();

                if (defaultContextClass == null) {
                    defaultContextClass = super.getDefaultContextClass();
                }

                return defaultContextClass;
            }

            /**
             * 多线程初始化components
             */
            @Override
            public void finishRefresh() {

                this.getWebxComponents().getWebxRootController().onFinishedProcessContext();
                this.getServletContext().log("Start to concurrent load components");

                int poolSize = Runtime.getRuntime().availableProcessors() * 2;
                int componentNum = this.getWebxComponents().getComponentNames().length;
                ServletContext context = this.getServletContext();

                if (componentNum < poolSize) {
                    // 针对模块较少的应用做的优化
                    poolSize = componentNum;
                }

                ExecutorService executorService = Executors.newFixedThreadPool(poolSize);
                CountDownLatch countDownLatch = new CountDownLatch(componentNum);

                for (WebxComponent component : this.getWebxComponents()) {

                    Thread loader = new FastLoader(component, context, countDownLatch);
                    if (!executorService.isShutdown()) {
                        executorService.submit(loader);
                    }

                }

                // wait until all components are loaded.
                try {
                    countDownLatch.await();
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }

                this.getServletContext().log("WebxComponents: initialization completed");
            }

        };
    }

    protected Class<? extends WebxComponentsContext> getDefaultContextClass() {
        return null;
    }

    class FastLoader extends Thread {

        private WebxComponent  component;
        private ServletContext getServletContext;
        private CountDownLatch countDownLatch;

        public FastLoader(WebxComponent component, ServletContext getServletContext,
                          CountDownLatch countDownLatch) {
            this.component = component;
            this.getServletContext = getServletContext;
            this.countDownLatch = countDownLatch;
        }

        @Override
        public void run() {

            try {
                getServletContext.log("Initializing Spring sub WebApplicationContext: "
                        + component.getName());

                WebxComponentContext wcc = (WebxComponentContext) component.getApplicationContext();
                WebxController controller = component.getWebxController();

                wcc.refresh();
                controller.onFinishedProcessContext();

            } finally {
                countDownLatch.countDown();
            }

        }

    }
}