观察者模式

package test.client;

import java.util.ArrayList;
import java.util.List;

public class ObserverTest {
    
    //使用场景
    public static void main(String[] args){
        FlyHpObserver objOne = new FlyHpObserver();
        HeadHpObserver objTwo = new HeadHpObserver();
        HpStateObserver objThree = new HpStateObserver();
        HpAttribute subject = new HpAttribute();
        subject.addObserver(objOne);
        subject.addObserver(objTwo);
        subject.addObserver(objThree);
        subject.setW_HpValue(100);
    }
}

interface IObserver
{
    public void update(int hp);
}

class FlyHpObserver implements IObserver{

    @Override
    public void update(int hp) {
        System.out.println("fly hp bar and the current hp is " + hp);
    }
}

class HeadHpObserver implements IObserver{

    @Override
    public void update(int hp) {
        System.out.println("head hp changed and  the current hp is " + hp);
    }
}

class HpStateObserver implements IObserver{

    @Override
    public void update(int hp) {
        System.out.println("hp changed and  the current hp is " + hp);
    }
}

interface ISubject
{
    public void addObserver(IObserver obj);
    public void removeObserver(IObserver obj);
    public void notifyAllObserver();
}

class HpAttribute implements ISubject{
    private int w_HpValue;
    
    private List<IObserver> w_ObserverList = new ArrayList<IObserver>();
    public int getW_HpValue() {
        return w_HpValue;
    }

    public void setW_HpValue(int w_HpValue) {
        this.w_HpValue = w_HpValue;
        notifyAllObserver();         //当玩家血量改变的时候通知观察者刷新数据
    }

    @Override
    public void addObserver(IObserver obj) {
        // TODO Auto-generated method stub
        w_ObserverList.add(obj);
    }

    @Override
    public void removeObserver(IObserver obj) {
        // TODO Auto-generated method stub
        w_ObserverList.remove(obj);
    }

    @Override
    public void notifyAllObserver() {
        int size = w_ObserverList.size();
        for(int i = 0 ; i < size ; i++){
            w_ObserverList.get(i).update(w_HpValue);
        }
    }
    
}