Java设计模式之java状态模式详解

public class Context {
    //持有一个State类型的对象实例
    private State state;

    public void setState(State state) {
        this.state = state;
    }
    
    public void request(String sampleParameter) {
        //转调state来处理
        state.handle(sampleParameter);
    }
}

public interface State {
    
    public void handle(String sampleParameter);
}

public class ConcreteStateA implements State {

    @Override
    public void handle(String sampleParameter) {
        
        System.out.println("ConcreteStateA handle ：" + sampleParameter);
    }

}

public class ConcreteStateB implements State {

    @Override
    public void handle(String sampleParameter) {
        
        System.out.println("ConcreteStateB handle ：" + sampleParameter);
    }

}

public class Client {

    public static void main(String[] args){
        //创建状态
        State state = new ConcreteStateB();
        //创建环境
        Context context = new Context();
        //将状态设置到环境中
        context.setState(state);
        //请求
        context.request("test");
    }
}

//抽象状态类
public interface VoteState
{
    
    public void vote(String user,String voteItem,VoteManager voteManager);
}

//具体状态类---正常投票
public class NORMalVoteState implements VoteState
{

    @Override
    public void vote(String user, String voteItem, VoteManager voteManager) {
        //正常投票，记录到投票记录中
        voteManager.getMapVote().put(user, voteItem);
        System.out.println("恭喜投票成功");
    }
}

//具体状态类--重复投票
public class RepeatVoteState implements VoteState
{

    @Override
    public void vote(String user, String voteItem, VoteManager voteManager) {
            //重复投票，暂时不做处理
            System.out.println("请不要重复投票");
    }
}

//恶意刷票
public class SpiteVoteState implements VoteState{
    @Override
    public void vote(String user, String voteItem, VoteManager voteManager) {
        // 恶意投票，取消用户的投票资格，并取消投票记录
        String str = voteManager.getMapVote().get(user);
        if(str != null){
            voteManager.getMapVote().remove(user);
        }
        System.out.println("你有恶意刷屏行为，取消投票资格");
    }
}

//黑名单
public class BlackVoteState implements VoteState
{
    @Override
    public void vote(String user, String voteItem, VoteManager voteManager) {
//记录黑名单中，禁止登录系统
        System.out.println("进入黑名单，将禁止登录和使用本系统");
    }
}

//环境类
public class VoteManager
{
    //维护一个抽象状态对象
    private VoteState state;
    //记录用户投票的结果，Map<String,String>对应Map<用户名称，投票的选项>
    private Map<String,String> mapVote = new HashMap<String,String>();
    //记录用户投票次数，Map<String,Integer>对应Map<用户名称，投票的次数>
    private Map<String,Integer> mapVoteCount = new HashMap<String,Integer>();
    
    public Map<String, String> getMapVote() {
        return mapVote;
    }
    
    public void vote(String user,String voteItem){
        //1.为该用户增加投票次数
        //从记录中取出该用户已有的投票次数
        Integer oldVoteCount = mapVoteCount.get(user);
        if(oldVoteCount == null){
            oldVoteCount = 0;
        }
        oldVoteCount += 1;
        mapVoteCount.put(user, oldVoteCount);
        //2.判断该用户的投票类型，就相当于判断对应的状态
        //到底是正常投票、重复投票、恶意投票还是上黑名单的状态
        if(oldVoteCount == 1){
            state = new NormalVoteState();
        }
        else if(oldVoteCount > 1 && oldVoteCount < 5){
            state = new RepeatVoteState();
        }
        else if(oldVoteCount >= 5 && oldVoteCount <8){
            state = new SpiteVoteState();
        }
        else if(oldVoteCount > 8){
            state = new BlackVoteState();
        }
        //然后转调状态对象来进行相应的操作
        state.vote(user, voteItem, this);
    }
}

public class Client
{
    public static void main(String[] args) {

        VoteManager vm = new VoteManager();
        for(int i=0;i<9;i++){
            vm.vote("u1","A");
        }
    }
}