深入理解Java设计模式之状态模式

目录

• 一、什么是状态模式
• 二、状态模式的结构
• 三、状态模式的使用场景
• 四、状态模式和策略模式对比
• 五、状态模式的优缺点
• 六、状态模式的实现
• 七、总结

public abstract class State
{
    public abstract void WriteProgram(Work w);
}

//上午工作状态
public class ForeNoonState : State
{
    public override void WriteProgram(Work w)
    {
        if (w.Hour < 12)
        {
            Console.WriteLine("当前时间：{0}点，上午工作，精神百倍", w.Hour);
        }
        else
        {
            //超过12点，则转入中午工作状态
            w.SetState(new NoonState());
            w.WriteProgram();
        }
    }
}

//中午工作状态
public class NoonState : State
{
    public override void WriteProgram(Work w)
    {
        if (w.Hour < 13)
        {
            Console.WriteLine("当前时间：{0}点，吃午饭，午休", w.Hour);
        }
        else
        {
            //超过13点，则转入下午工作状态
            w.SetState(new AfterNoonState());
            w.WriteProgram();
        }
    }
}

//下午工作状态
public class AfterNoonState : State
{
    public override void WriteProgram(Work w)
    {
        if (w.Hour < 17)
        {
            Console.WriteLine("当前时间：{0}点，下午工作，继续努力", w.Hour);
        }
        else
        {
            //超过17点，则转入晚上工作状态
            w.SetState(new EveningState());
            w.WriteProgram();
        }
    }
}

//晚上工作状态
public class EveningState : State
{
    public override void WriteProgram(Work w)
    {
        if (w.Finish)
        {
            //如果状态已完成，则转入下班状态
            w.SetState(new RestState());
            w.WriteProgram();
        }
        else
        {
            if (w.Hour < 21)
            {
                Console.WriteLine("当前时间：{0}点，加班", w.Hour);
            }
            else
            {
                //超过21点，则转入睡眠工作状态
                w.SetState(new SleepingState());
                w.WriteProgram();
            }
        }
    }
}

//睡眠工作状态
public class SleepingState : State
{
    public override void WriteProgram(Work w)
    {
        Console.WriteLine("当前时间：{0}点，睡觉", w.Hour);
    }
}
//下班休息状态
public class RestState : State
{
    public override void WriteProgram(Work w)
    {
        Console.WriteLine("当前时间：{0}点，下班", w.Hour);
    }
}

public class Work
{
    private State current;
    public Work()
    {
        //工作初始化为上午工作状态
        current = new ForeNoonState();
    }
    //“钟点”属性，状态转换的依据
    private double hour;
    public double Hour
    {
        get { return hour; }
        set { hour = value; }
    }
    //“任务完成”属性，是否能下班的依据
    private bool finish = false;
    public bool Finish
    {
        get { return finish; }
        set { finish = value; }
    }
     public void SetState(State s)
    {
        current = s;
    }
     public void WriteProgram()
    {
        current.WriteProgram(this);
    }
}

class Program
{
    //客户端代码
    static void Main(string[] args)
    {
        Work w = new Work();
        w.Hour = 9;
        w.WriteProgram();
        w.Hour = 10;
        w.WriteProgram();
        w.Hour = 12;
        w.WriteProgram();
        w.Hour = 13;
        w.WriteProgram();
        w.Hour = 14;
        w.WriteProgram();
        w.Hour = 17;
         w.Finish = false;
        //w.Finish = true;
        w.WriteProgram();
        w.Hour = 19;
        w.WriteProgram();
        w.Hour = 22;
        w.WriteProgram();
         Console.Read();
    }
}