/**
 * 状态模式:state pattern
 *
 * 不使用状态模式时，代码可能会是这样:
 * if (state.equals("awake")){
 *        System.out.println("awake:工作.");
 * }
 * else if(state.equals("asleep")){
 *        System.out.println("asleep:做梦.");
 * }
 * else ...
 *
 * @version 2009-5-18
 * @author Winty(wintys@gmail.com)
 */
public class StateTest{
    public static void main(String[] args){
        Person person = new Person();

        person.doAction();

        person.setState(new Asleep());
        person.doAction();
    }
}

/**
 *环境:Context
 */
class Person{
    private State state = new Awake();

    public void setState(State state){
        this.state = state;
    }

    public void doAction(){
        state.doAction();
    }
}

/**
 *抽象状态:State
 */
interface State{
    public void doAction();
}

/**
 *具体状态
 */
class Awake implements State{
    public void doAction(){
        System.out.println("awake:工作.");
    }
}

/**
 *具体状态
 */
class Asleep implements State{
    public void doAction(){
        System.out.println("asleep:做梦.");
    }
}