线程设计之future模式

Posted 2020-10-15

Main

package com.cmos.ngkm.web.controller.basic;

public class Main {
    public static void main(String[] args) throws  InterruptedException{
        FutureClient fc = new FutureClient();
        Data data = fc.request("请求参数");
        System.out.println("请求发送成功！");
        System.out.println("做其它的事情...");

        String result = data.getRequest();
        System.out.println(result);
    }
}

FutureClient

package com.cmos.ngkm.web.controller.basic;

public class FutureClient {
    public Data request(final String queryStr){
        //1.我想要一个代理对象（Data接口的实现类）先返回给发送请求的客户端，告诉他请求已经接收到，可以做其他事情
        final FutureData futureData = new FutureData();
        //2.启动一个新的线程，去加载真实的数据，传递给这个代理对象
        new Thread(new Runnable() {
            @Override
            public void run() {
                //这个新的线程可以去慢慢的加载真实对象，然后传递给代理对象
                RealData realData = new RealData(queryStr);
                futureData.setRealData(realData);
            }
        }).start();
        return futureData;
    }

}

FutureData

package com.cmos.ngkm.web.controller.basic;

import groovy.transform.Synchronized;

public class FutureData implements Data{
    private RealData realData;

    private boolean isReady = false;
    @Override
    public synchronized String getRequest() {
        while(!isReady)
        {
            try{
                wait();
            }catch(InterruptedException e){
                e.printStackTrace();
            }
        }
        return this.realData.getRequest();
    }

    public synchronized void setRealData(RealData realData) {
        if(isReady)
        {
            return;
        }
        this.realData = realData;
        isReady = true;
        notify();
    }
}

RealData

package com.cmos.ngkm.web.controller.basic;

public class RealData implements Data{
    private String result;

    public RealData(String queryStr){
        System.out.println("根据"+queryStr+"进行查询，这是一个很耗时的操作...");
       try{
           Thread.sleep(5000);
       }catch(InterruptedException e)
       {
           e.printStackTrace();
       }
        result = "查询结果";
    }

    @Override
    public String getRequest() {
        return result;
    }
}

Data

package com.cmos.ngkm.web.controller.basic;

public interface Data {
    String getRequest();
}