一个糖果机项目
智能糖果机，用Java软件控制糖果机：
待机
投入一元硬币
转动把手
滑落一颗糖果
待机（根据机器内糖果库存情况，是否提示售罄）
项目新需求的困惑
加入游戏元素：有10%的概率可以拿到2粒糖果
package com.java.test.statemode;
public class CandyMachine {
final static int SoldOutState = 0;
final static int OnReadyState = 1;
final static int HasCoin = 2;
final static int SoldState = 3;
private int state = SoldOutState;
private int count = 0;
public CandyMachine(int count) {
this.count = count;
if (count > 0) {
state = OnReadyState;
}
}
public void insertCoin() {
switch (state) {
case SoldOutState:
System.out.println("you can't insert coin,the machine sold out!");
break;
case OnReadyState:
state = HasCoin;
System.out
.println("you have inserted a coin,next,please turn crank!");
break;
case HasCoin:
System.out.println("you can't insert another coin!");
break;
case SoldState:
System.out.println("please wait!we are giving you a candy!");
break;
}
}
public void returnCoin() {
switch (state) {
case SoldOutState:
System.out
.println("you can't return,you haven't inserted a coin yet!");
break;
case OnReadyState:
System.out.println("you haven't inserted a coin yet!");
break;
case HasCoin:
System.out.println("coin return!");
state = OnReadyState;
break;
case SoldState:
System.out.println("sorry,you already have turned the crank!");
break;
}
}
public void turnCrank() {
switch (state) {
case SoldOutState:
System.out.println("you turned,but there are no candies!");
break;
case OnReadyState:
System.out.println("you turned,but you haven't inserted a coin!");
break;
case HasCoin:
System.out.println("crank turn...!");
state = SoldState;
dispense();
break;
case SoldState:
System.out
.println("we are giving you a candy,turning another get nothing,!");
break;
}
}
private void dispense() {
count = count - 1;
System.out.println("a candy rolling out!");
if (count > 0) {
state = OnReadyState;
} else {
System.out.println("Oo,out of candies");
state = SoldOutState;
}
}
public void printstate() {
switch (state) {
case SoldOutState:
System.out.println("***SoldOutState***");
break;
case OnReadyState:
System.out.println("***OnReadyState***");
break;
case HasCoin:
System.out.println("***HasCoin***");
break;
case SoldState:
System.out.println("***SoldState***");
break;
}
}
}
测试类
package com.java.test.statemode;
public class MainTest {
public static void main(String[] args) {
CandyMachine mCandyMachine=new CandyMachine(1);
mCandyMachine.printstate();
mCandyMachine.insertCoin();
mCandyMachine.printstate();
mCandyMachine.turnCrank();
mCandyMachine.printstate();
mCandyMachine.insertCoin();
mCandyMachine.printstate();
mCandyMachine.turnCrank();
mCandyMachine.printstate();
}
}
状态模式方案
状态模式：能根据内部状态的变化，改变对象的行为，看起来好像修改了类
package com.java.test.statemode.state;
public interface State {
public void insertCoin();
public void returnCoin();
public void turnCrank();
public void dispense();
public void printstate();
}
package com.java.test.statemode.state;
public class OnReadyState implements State {
private CandyMachine mCandyMachine;
public OnReadyState(CandyMachine mCandyMachine)
{
this.mCandyMachine=mCandyMachine;
}
@Override
public void insertCoin() {
// TODO Auto-generated method stub
System.out
.println("you have inserted a coin,next,please turn crank!");
mCandyMachine.setState(mCandyMachine.mHasCoin);
}
@Override
public void returnCoin() {
// TODO Auto-generated method stub
System.out.println("you haven't inserted a coin yet!");
}
@Override
public void turnCrank() {
// TODO Auto-generated method stub
System.out.println("you turned,but you haven't inserted a coin!");
}
@Override
public void dispense() {
// TODO Auto-generated method stub
}
@Override
public void printstate() {
// TODO Auto-generated method stub
System.out.println("***OnReadyState***");
}
}
package com.java.test.statemode.state;
public class SoldOutState implements State {
private CandyMachine mCandyMachine;
public SoldOutState(CandyMachine mCandyMachine)
{
this.mCandyMachine=mCandyMachine;
}
@Override
public void insertCoin() {
// TODO Auto-generated method stub
System.out.println("you can't insert coin,the machine sold out!");
}
@Override
public void returnCoin() {
// TODO Auto-generated method stub
System.out
.println("you can't return,you haven't inserted a coin yet!");
}
@Override
public void turnCrank() {
// TODO Auto-generated method stub
System.out.println("you turned,but there are no candies!");
}
@Override
public void dispense() {
// TODO Auto-generated method stub
}
@Override
public void printstate() {
// TODO Auto-generated method stub
System.out.println("***SoldOutState***");
}
}
package com.java.test.statemode.state;
public class SoldState implements State {
private CandyMachine mCandyMachine;
public SoldState(CandyMachine mCandyMachine)
{
this.mCandyMachine=mCandyMachine;
}
@Override
public void insertCoin() {
// TODO Auto-generated method stub
System.out.println("please wait!we are giving you a candy!");
}
@Override
public void returnCoin() {
// TODO Auto-generated method stub
System.out.println("you haven't inserted a coin yet!");
}
@Override
public void turnCrank() {
// TODO Auto-generated method stub
System.out
.println("we are giving you a candy,turning another get nothing,!");
}
@Override
public void dispense() {
// TODO Auto-generated method stub
mCandyMachine.releaseCandy();
if (mCandyMachine.getCount() > 0) {
mCandyMachine.setState(mCandyMachine.mOnReadyState);
} else {
System.out.println("Oo,out of candies");
mCandyMachine.setState(mCandyMachine.mSoldOutState);
}
}
@Override
public void printstate() {
// TODO Auto-generated method stub
System.out.println("***SoldState***");
}
}
package com.java.test.statemode.state;
public class WinnerState implements State {
private CandyMachine mCandyMachine;
public WinnerState(CandyMachine mCandyMachine) {
this.mCandyMachine = mCandyMachine;
}
@Override
public void insertCoin() {
// TODO Auto-generated method stub
System.out.println("please wait!we are giving you a candy!");
}
@Override
public void returnCoin() {
// TODO Auto-generated method stub
System.out.println("you haven't inserted a coin yet!");
}
@Override
public void turnCrank() {
// TODO Auto-generated method stub
System.out
.println("we are giving you a candy,turning another get nothing,!");
}
@Override
public void dispense() {
// TODO Auto-generated method stub
mCandyMachine.releaseCandy();
if (mCandyMachine.getCount() == 0) {
mCandyMachine.setState(mCandyMachine.mSoldOutState);
} else {
System.out.println("you are a winner!you get another candy!");
mCandyMachine.releaseCandy();
if (mCandyMachine.getCount() > 0) {
mCandyMachine.setState(mCandyMachine.mOnReadyState);
} else {
System.out.println("Oo,out of candies");
mCandyMachine.setState(mCandyMachine.mSoldOutState);
}
}
}
@Override
public void printstate() {
// TODO Auto-generated method stub
System.out.println("***WinnerState***");
}
}
package com.java.test.statemode.state;
import java.util.Random;
public class HasCoin implements State {
private CandyMachine mCandyMachine;
public HasCoin(CandyMachine mCandyMachine) {
this.mCandyMachine = mCandyMachine;
}
@Override
public void insertCoin() {
// TODO Auto-generated method stub
System.out.println("you can't insert another coin!");
}
@Override
public void returnCoin() {
// TODO Auto-generated method stub
System.out.println("coin return!");
mCandyMachine.setState(mCandyMachine.mOnReadyState);
}
@Override
public void turnCrank() {
// TODO Auto-generated method stub
System.out.println("crank turn...!");
Random ranwinner=new Random();
int winner=ranwinner.nextInt(10);
if(winner==0)
{
mCandyMachine.setState(mCandyMachine.mWinnerState);
}else
{
mCandyMachine.setState(mCandyMachine.mSoldState);
}
}
@Override
public void dispense() {
}
@Override
public void printstate() {
// TODO Auto-generated method stub
System.out.println("***HasCoin***");
}
}
现在变得非常简洁
package com.java.test.statemode.state;
public class CandyMachine {
State mSoldOutState;
State mOnReadyState;
State mHasCoin;
State mSoldState;
State mWinnerState;
private State state;
private int count = 0;
public CandyMachine(int count) {
this.count = count;
mSoldOutState = new SoldOutState(this);
mOnReadyState = new OnReadyState(this);
mHasCoin = new HasCoin(this);
mSoldState = new SoldState(this);
mWinnerState = new WinnerState(this);
if (count > 0) {
state = mOnReadyState;
} else {
state = mSoldOutState;
}
}
public void setState(State state) {
this.state = state;
}
public void insertCoin() {
state.insertCoin();
}
public void returnCoin() {
state.returnCoin();
}
public void turnCrank() {
state.turnCrank();
state.dispense();
}
void releaseCandy() {
// TODO Auto-generated method stub
if (count > 0) {
count = count - 1;
System.out.println("a candy rolling out!");
}
}
public int getCount() {
return count;
}
public void printstate() {
state.printstate();
}
}
测试类
package com.java.test.statemode.state;
public class MainTest {
public static void main(String[] args) {
CandyMachine mCandyMachine = new CandyMachine(6);
mCandyMachine.printstate();
mCandyMachine.insertCoin();
mCandyMachine.printstate();
mCandyMachine.turnCrank();
mCandyMachine.printstate();
mCandyMachine.insertCoin();
mCandyMachine.printstate();
mCandyMachine.turnCrank();
mCandyMachine.printstate();
}
}