Java设计模式之状态模式

package com.whut.state;

public interface State {
void insertQuarter();
void ejectQuarter();
void turnCrank();
void dispense();
}

package com.whut.state;
//状态模式
public  class GumballMachine {

private State soleOutState;
private State noQuarterState;
private State hasQuarterState;
private State soldState;
private State winnerState;

private State state=soleOutState;
private  int count=0;

public GumballMachine( int count)
{
soleOutState= new SoldOutState( this);
noQuarterState= new NoQuarterState( this);
hasQuarterState= new HasQuarterState( this);
soldState= new SoldState( this);
winnerState= new WinnerState( this);
this.count=count;
if(count>0)
state=noQuarterState;
}
//投入25分的动作
public  void insertQuarter()
{
state.insertQuarter();
}

//退回25分的动作
public  void ejectQuarter()
{
state.ejectQuarter();
}

//转动曲柄
public  void turnCrank()
{
state.turnCrank();
state.dispense();
}

//释放糖果
public  void releaseBall()
{
System.out.println( "A gunmball comes rolling out the slot from machine");
if(count!=0)
count=count-1;
}

//打印机器当前状态
@Override
public String toString()
{
return "-----------"+ "\nThe machine state:"+state.toString()+ "\ncount="+count+ "\n-----------";
}

//设置状态
public void setState(State st)
{
this.state=st;
}

//获取状态
public State getSoleOutState() {
return soleOutState;
}
public State getNoQuarterState() {
return noQuarterState;
}
public State getHasQuarterState() {
return hasQuarterState;
}
public State getSoldState() {
return soldState;
}
//获取总的数目
public int getCount() {
return count;
}
public State getWinnerState() {
return winnerState;
}

}

package com.whut.state;

public  class NoQuarterState  implements State {

private GumballMachine gumballMachine;
public NoQuarterState(GumballMachine gumballMachine)
{
this.gumballMachine=gumballMachine;
}

@Override
public void insertQuarter() {
System.out.println( "You inserted a quarter");
gumballMachine.setState(gumballMachine.getHasQuarterState());
}

@Override
public void ejectQuarter() {
System.out.println( "You haven't inserted a quarter");
}

@Override
public void turnCrank() {
System.out.println( "You turned,but there's no quarter");
}

@Override
public void dispense() {
System.out.println( "You need to pay a quarter first");
}
}