设计模式---状态模式

 

以前的示例


public class Person {
	private int hour;

	public int getHour() {
		return hour;
	}

	public void setHour(int hour) {
		this.hour = hour;
	}
	
	public void doSomething(){
		if(hour == 7) {
			System.out.println("吃早餐");
		} else if(hour == 12) {
			System.out.println("吃中饭");
		} else if(hour == 18) {
			System.out.println("吃晚饭");
		} else {
			System.out.println(hour + "未定义");
		}
	}
}

 


public class MainClass {
	public static void main(String[] args) {
		Person person = new Person();
		
		person.setHour(7);
		person.doSomething();
		
		person.setHour(12);
		person.doSomething();
		
		person.setHour(18);
		person.doSomething();
		
		person.setHour(8);
		person.doSomething();
	}
}

现在的示例

package com.ibeifeng.ex3;

public abstract class State {
	public abstract void  doSomething(Person person);
}

package com.ibeifeng.ex3;

public class SState extends State {

	public void doSomething(Person person) {
		if(person.getHour() == 18) {
			System.out.println("吃晚饭");
		} else {
			person.setState(new NoState());
			person.doSomething();
		}
	}

}

 

package com.ibeifeng.ex3;

public class NoState extends State {

	public void doSomething(Person person) {
		System.out.println(person.getHour() +  "未定义");
	}

}

 

package com.ibeifeng.ex3;

public class LState extends State{

	public void doSomething(Person person) {
		if(person.getHour() == 12) {
			System.out.println("吃中饭");
		} else {
			person.setState(new SState());
			person.doSomething();
		}
	}

}

 

package com.ibeifeng.ex3;

public class MState extends State {

	public void doSomething(Person person) {
		if(person.getHour() == 7) {
			System.out.println("吃早餐");
		} else {
			person.setState(new LState());
			person.doSomething();
		}
	}

}

 

package com.ibeifeng.ex3;

public class Person {
	private int hour;
	private State state;

	public int getHour() {
		return hour;
	}

	public void setHour(int hour) {
		this.hour = hour;
	}
	
	public Person() {
		state = new MState();
	}
	
	public void doSomething(){
//		if(hour == 7) {
//			state = new MState();
//			state.doSomething();
//		} else if(hour == 12) {
//			state = new LState();
//			state.doSomething();
//		} else if(hour == 18) {
//			state = new SState();
//			state.doSomething();
//		} else {
//			state = new NoState();
//			state.doSomething();
//		}
		state.doSomething(this);
		//复位，都所以方法以后再执行。
		state = new MState();
	}

	public State getState() {
		return state;
	}

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

 

package com.ibeifeng.ex3;

public class MainClass {
	public static void main(String[] args) {
		Person person = new Person();
		
		person.setHour(7);
		person.doSomething();
		
		person.setHour(12);
		person.doSomething();
		
		person.setHour(18);
		person.doSomething();
		
		person.setHour(8);
		person.doSomething();
		
		person.setHour(7);
		person.doSomething();
		
		person.setHour(18);
		person.doSomething();
		
	}
}