Future模式简单实现

概述，Future模式是多线程开发中比较常见模式，核心思想是异步调用，思路是执行函数时，马上得到返回结果，但是并不急于处理，而去执行其它业务逻辑，最后再使用比较慢的数据，就不存在无谓的等待，充分利用的所有的时间片段。提高响应速度
FutureData


public class FutureData implements Data {
protected RealData realdata=null;  //FutureData是真实数据包装
protected boolean isReady=false;
public synchronized void setRealdata(RealData realdata) {
if (isReady) {
return;
        }
this.realdata=realdata;
        isReady=true;
        notifyAll();  //数据完成，通知getResult
    }
@Override
public String getResult() {
// TODO Auto-generated method stub
while(!isReady)
        {
try {
                wait();
            } catch (InterruptedException e) {
// TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
return realdata.result;
    }

}

3.RealData


public class RealData implements Data {
protected final String result;

public RealData(String para) {
// TODO Auto-generated constructor stub
        StringBuffer sb=new StringBuffer();
for(int i=0;i<5;i++)
        {
            sb.append(para);
try {
                Thread.sleep(1000);  //模拟很慢的加载速度
            } catch (InterruptedException e) {
// TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
        System.out.println("数据完成");
        System.out.println(System.currentTimeMillis()/1000);
        result=sb.toString();
    }

@Override
public String getResult() {
// TODO Auto-generated method stub
return result;
    }

}

4.Data


public interface Data {
public String getResult();
}

5.client


public class Client {
public Data request (final String querystr)
  {
final FutureData futureData=new FutureData();
new Thread(){
public void run() {
             RealData realData=new  RealData(querystr);
             futureData.setRealdata(realData);
         };
      }.start();
return futureData;
  }
}

6.Main


public class Main {

public static void main(String[] args) {
// TODO Auto-generated method stub
      Client client=new Client();
      Data data=client.request("name");
      System.out.println("请求完毕");
try {
        Thread.sleep(7000);
    } catch (InterruptedException e) {
// TODO Auto-generated catch block
        e.printStackTrace();
    }
      System.out.println(System.currentTimeMillis()/1000);
      System.out.println("数据"+data.getResult());
    }

}

7.参考自java高并发程序设计

秒客网

Future模式简单实现

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