上一篇博客一步步学习java并发编程模式之Active Object模式（一）中介绍了Active Object的一些思想和作用，这篇文章打算自己写1个简单的模拟Active Object的例子。

假设有一个天气预报计算服务，见以下代码：

package activeobject.aty;

// 模拟天气预报的查询结果
// 今日天气实况：气温：4℃；风向/风力：西北风 1级；湿度：74%；空气质量：中；紫外线强度：最弱
public class WeatherResult
{
    // 气温
    private int temperature;

    // 湿度
    private String dampness;

    // 风向
    private String windDirection;

    public int getTemperature()
    {
        return temperature;
    }

    public void setTemperature(int temperature)
    {
        this.temperature = temperature;
    }

    public String getDampness()
    {
        return dampness;
    }

    public void setDampness(String dampness)
    {
        this.dampness = dampness;
    }

    public String getWindDirection()
    {
        return windDirection;
    }

    public void setWindDirection(String windDirection)
    {
        this.windDirection = windDirection;
    }

    @Override
    public String toString()
    {
        return "WeatherResult [temperature=" + temperature + ", dampness=" + dampness + ", windDirection="
                + windDirection + "]";
    }

}

package activeobject.aty.service;

import activeobject.aty.WeatherResult;

public class WeatherService
{
    public static WeatherResult getWeatherInfo(String city, String day)
    {
        try
        {
            // 模拟耗时操作,调用该方法的线程,要挂起5s
            Thread.sleep(5 * 1000);
        }
        catch (InterruptedException e)
        {

        }

        WeatherResult result = new WeatherResult();
        result.setTemperature(28);
        result.setWindDirection("西北风");
        result.setDampness("74%");
        
        return result;
    }

}

    public static void testSyncCall()
    {
        // 1.调用天气计算服务,开始计算深圳的天气情况(开始计算)
        WeatherResult info = WeatherService.getWeatherInfo("广东深圳", "2014-03-14");

        System.out.println("After calling weather service,i was blocked.");

        System.out.println("Now,i really need weather result to continue.");

        System.out.println("天气查询结果:" + info);
    }

package activeobject.aty.proxy;

import activeobject.aty.call.EvaluateWeatherTask;
import activeobject.aty.future.WeatherFuture;

public class WeatherProxy
{
    public static WeatherFuture getWeatherInfo(String city, String day)
    {
        WeatherFuture future = new WeatherFuture();

        new Thread(new EvaluateWeatherTask(future, city, day)).start();

        return future;
    }

package activeobject.aty.service;

import activeobject.aty.WeatherResult;
import activeobject.aty.future.WeatherFuture;

public class EvaluateWeatherTask implements Runnable
{
    private WeatherFuture future;

    private String city;

    private String day;

    public EvaluateWeatherTask(WeatherFuture future, String city, String day)
    {
        this.future = future;
        this.city = city;
        this.day = day;
    }

    @Override
    public void run()
    {
        WeatherResult r = WeatherService.getWeatherInfo(city, day);
        future.setResult(r);
        future.setDone(true);
    }

}

package activeobject.aty.future;

import activeobject.aty.WeatherResult;

public class WeatherFuture
{
    private boolean isDone = false;

    private WeatherResult result = null;

    public WeatherResult get()
    {
        while (!isDone)
        {
           //模拟阻塞 
        }

        return result;
    }

    public void setDone(boolean isDone)
    {
        this.isDone = isDone;
    }

    public void setResult(WeatherResult result)
    {
        this.result = result;
    }

}

public static void testAsyncCall() throws Exception
{
        // 1.调用天气计算服务,开始计算深圳的天气情况(开始计算)
        WeatherFuture future = WeatherProxy.getWeatherInfo("广东深圳", "2014-03-14");

        // 2.后台在计算天气服务中.当前线程没有阻塞,仍然可以继续执行.
        System.out.println("After calling weather service,i am still running.");

        // 3.The current thread is not blocked, do something else here...
        // Thread.sleep(5 * 1000);

        // 4.与天气计算结果无关的代码执行完毕.
        System.out.println("Now,i really need weather result to continue.");

        // 5.如果计算天气还没有结束,那么当前线程挂起,等候计算完成.
        WeatherResult info = future.get();
        System.out.println("天气查询结果:" + info);
}

一步步学习java并发编程模式之Active Object模式（二）,布布扣,bubuko.com

一步步学习java并发编程模式之Active Object模式（二）