状态模式银行账户

今天做了状态模式---银行账户的实验，用了差不多两个小时的时间，理解了状态模式的原理，下面是状态模式的简介以及实验要求和实现。

实验要求：

用Java代码模拟实现课堂上的“银行账户”的实例，要求编写客户端测试代码模拟用户存款和取款，注意账户对象状态和行为的变化。

截图：

代码：

package 实验22状态模式;

public class ATM {
/*所有状态*/
private ATMState readyState;
private ATMState noCashState;
private ATMState noServiceState;

private ATMState currState;//当前状态
private int totalAmount;//账户现钞总数

/*测试用的临时变量*/
private String pwd;//密码
private int balance;//余额
private int amount;//取款金额

public ATM(int totalAmount, int balance, int amount, String pwd) throws Exception{
//初始化所有状态
readyState = new ReadyState(this);
noCashState = new NoCashState(this);
noServiceState = new NoServiceState(this);

if(totalAmount > 0){
currState = readyState;
}
else if(totalAmount == 0){
currState = noCashState;
}
else{
throw new Exception();
}

//初始化测试数据
this.totalAmount = totalAmount;
this.balance = balance;
this.amount = amount;
this.pwd = pwd;
}

/*把具体行为委托给状态对象*/
/**
* 插卡
*/
public void insertCard(){
currState.insertCard();
}

/**
* 提交密码
*/
public void submitPwd(){
currState.submitPwd();
}

/**
* 取款
*/
public void getCash(){
currState.getCash();
}

/**
* 查询余额
*/
public void queryBalance(){
currState.queryBalance();
}

/**
* 取卡
*/
public void ejectCard(){
currState.ejectCard();
}
public String toString(){
return "账户总额￥" + totalAmount;
}
public String SKT() {
if(totalAmount >= 0) {
return "账户状态为绿色正常状态，既可以存，也可以取款";
}
if(totalAmount >= -1000 && totalAmount < 0) {
return "账户状态为蓝色欠费状态，既可以存，也可以取款";
}
if(totalAmount < -1000) {
return "账户状态为红色透支状态，只能存款";
}
return "";
}

/*此处略去大量getter and setter*/

public String getPwd(){
return pwd;
}
public int getBalance() {
return balance;
}
public int getTotalAmount() {
return totalAmount;
}
public int getAmount() {
return amount;
}

public void setTotalAmount(int totalAmount) {
this.totalAmount = totalAmount;
}

public void setBalance(int balance) {
this.balance = balance;
}

public ATMState getNoCashState() {
return noCashState;
}

public void setCurrState(ATMState currState) {
this.currState = currState;
}
}

package 实验22状态模式;

public interface ATMState {
public abstract void insertCard();
public abstract void submitPwd();
public abstract void getCash();
public abstract void queryBalance();
public abstract void ejectCard();
}

package 实验22状态模式;

public class NoServiceState implements ATMState{
private ATM atm;//保留状态持有者的引用，以便对其进行操作

public NoServiceState(ATM atm){
this.atm = atm;
}

@Override
public void insertCard() {
System.out.println("插卡失败，机器发生了故障");
}

@Override
public void submitPwd() {
System.out.println("密码提交失败，机器发生了故障");
}

@Override
public void getCash() {
System.out.println("取款失败，机器发生了故障");
}

@Override
public void queryBalance() {
System.out.println("余额查询失败，机器发生了故障");
}

@Override
public void ejectCard() {
System.out.println("取卡失败，机器发生了故障");
}
}

package 实验22状态模式;

public class ReadyState implements ATMState{
private ATM atm;//保留状态持有者的引用，以便对其进行操作
public ReadyState(ATM atm){
this.atm = atm;
}

@Override
public void insertCard() {
System.out.println("插卡完成");
}
@Override
public void submitPwd() {
System.out.println("密码提交完成");
//验证密码并做相应处理
if("6300".equals(atm.getPwd())){
System.out.println("密码验证通过");
}
else{
System.out.println("密码验证失败");
//弹出卡片
ejectCard();
}
}

@Override
public void getCash() {
//atm.getTotalAmount() >= atm.getAmount() && atm.getBalance() >= atm.getAmount()
if(atm.getTotalAmount() != 9999){
//更新账户余额
atm.setBalance(atm.getBalance() - atm.getAmount());
//更新机内现钞总数
atm.setTotalAmount(atm.getTotalAmount() - atm.getAmount());
System.out.println("吐出￥" + atm.getAmount());
System.out.println("取款完成");
//弹出卡片
ejectCard();
//检查机内余钞
if(atm.getTotalAmount() == 0){//若无钞，切换到NoService状态
atm.setCurrState(atm.getNoCashState());
System.out.println("无钞信息已经发送至银行");
}
}
else{
System.out.println("取款失败，余额不足");
//弹出卡片
ejectCard();
}
}

@Override
public void queryBalance() {
System.out.println("余额￥" + atm.getBalance());
System.out.println("余额查询完成");
}

@Override
public void ejectCard() {
System.out.println("取卡完成");
}
}

package 实验22状态模式;

public class shijian5_yinhangzhanghu {
public static void main(String[] args) {
/*测试数据*/
/* 机内总数账户余额取款金额密码
* 1000 500 200 123
* 1000 300 500 123
* 0 500 200 123
* */
try {
test(1000, 500, 200, "6300");
System.out.println("------------------------------------------------------------");
test(1000, 300, 1500, "6300");
System.out.println("------------------------------------------------------------");
test(-1500, 500, 200, "6300");
} catch (Exception e) {
System.out.println("账户余额小于-1000，账户状态为红色透支状态，请存钱后再取");
//System.out.println("机器故障，维修请求已经发送至维修方");
}
}

private static void test(int totalAmount, int balance, int amount, String pwd)throws Exception{
//创建ATM
ATM atm;
atm = new ATM(totalAmount, balance, amount, pwd);
//输出初始状态
System.out.println(atm.toString());
System.out.println(atm.SKT());
atm.insertCard();
atm.submitPwd();
atm.getCash();
//输出结束状态
System.out.println(atm.toString());
}
}