State状态模式
参考于下面的链接：
http://www.jdon.com/designpatterns/designpattern_State.htm
http://blog.csdn.net/qutr/archive/2006/08/01/1007617.aspx
State模式的定义: 不同的状态,不同的行为;或者说,每个状态有着相应的行为.
何时使用? State模式在实际使用中比较多,适合"状态的切换".
来段代码：
//先来一个状态：package State;public abstract class State{ /** *//** Creates a new instance of State */ public State() { } public abstract void opration(Context context);}//end class State//在来两个具体的State：public class ConcreteStateA extends State{ /** *//** Creates a new instance of ConcreteStateA */ public ConcreteStateA() { } public void opration(Context context) { System.out.println("The Concrete A"); context.setSate(new ConcreteStateB()); }//end opration() public static ConcreteStateA getInstance() { return new ConcreteStateA(); }//end getInstance()}public class ConcreteStateB extends State{ /** *//** Creates a new instance of ConcreteStateB */ public ConcreteStateB() { } public void opration(Context context) { System.out.println("The Concrete B"); context.setSate(new ConcreteStateA()); }//end opration() public static ConcreteStateB getInstance() { return new ConcreteStateB(); }//end getInstance() }//end class ConcreteStateB//来一个场景：public class Context{ private State state; /** *//** Creates a new instance of Context */ public Context() { } public void setSate(State stat) { state = stat; }//end setState() public void operation() { state.opration(this); }//end operation() }//end class Context//怎样调用：public static void main(String[] args){Context con = new Context();con.setSate(ConcreteStateA.getInstance());con.operation();con.operation();}//end main()?以上代码摘自上面介绍的blog中，不过有部分改动。下面是UML图 也是盗链的。。。。。
