设计模式-状态模式

状态模式：允许对象在内部状态改变时改变他的行为，对象看起来好像修改了它的类。

public interface State{
    public void des();
    public void action();
}
public class State1 implements State{
    Sys sys;
    public Sate1(Sys s)
    {
        this.sys=sys;
    }
    public void des(){
        .../ implements
    }
    public void action(){
        .../ change the state
        sys.setState(s.getState2());
    }
}
public class State2 implements State{
    Sys sys;
    public Sate2(Sys s)
    {
        this.sys=sys;
    }
    public void des(){
        .../ implements
    }
    public void action(){
        .../ change the state
        sys.setState(s.getState1());
    }
}
public class Sys {
    private State1 state1;
    private State2 state2;
    private State state;//record the system‘s state
    ....//state1 & state2‘s setter & getter
    public Sys(State state)
    {
        this.state=state;
    }
    public void setState(State state)
    {    
        this.state=state;
    }    
    public void aciton()
    {
        state.action();
    }
}