/*
     * 职责链模式(Chain of Responsibility)：
     * 使用多个物件都有机会处理请求，从而避免请求的发送者和接收者之间的耦合关系。将这个物件连成一条链，
     * 并沿着这条链传递该请求，直到有一个物件处理为止。
     */
    public class ResponsibilityMode
    {
        /// <summary>
        /// 示例方法
         /// </summary>
        /// <remarks>
        /// 示例说明：将一串数值根据相当的数值范围显示相应的内容。 数值request在1到10时由h1处理；10到20由h2处理；20到30由h3处理……
         /// </remarks>
        public void Main()
        {
            Handler h1 = new ConcreteHandlerOne();
            Handler h2 = new ConcreteHandlerTwo();
            Handler h3 = new ConcreteHandlerThree();
            h1.SetSeccessor(h2);
            h2.SetSeccessor(h3);
            int[] requests = { 2, 5, 14, 22, 18, 3, 27, 20 };
            foreach (int request in requests)
            {
                h1.HandleRequest(request);
            }
        }
    }

    /// <summary>
    /// 处理接口
    /// </summary>
    abstract class Handler
    {
        protected Handler successor;

        /// <summary>
        /// 设定继任者
        /// </summary>
        /// <param name="successor">继任者</param>
        public void SetSeccessor(Handler successor)
        {
            this.successor = successor;
        }

        /// <summary>
        /// 处理请求的抽象方法
        /// </summary>
        /// <param name="request"></param>
        public abstract void HandleRequest(int request);
    }
    /// <summary>
    /// 具体处理者类，处理它所负责的请求，可存取它的后继者。如查可处理请求，就处理之，]
    /// 否则就将该请求转发给它的后继者
    /// </summary>
    class ConcreteHandlerOne : Handler
    {
        public override void HandleRequest(int request)
        {
            //符合指定情况的，处理此请求
            if (request >= 0 && request < 10)
            {
                Console.WriteLine("{0} 处理请求 {1}", this.GetType().Name, request);
            }
            else if (base.successor != null) //不符合转移到下一位
            {
                successor.HandleRequest(request);
            }
        }
    }

    /// <summary>
    /// 处理者类2
    /// </summary>
    class ConcreteHandlerTwo : Handler
    {
        public override void HandleRequest(int request)
        {
            if (request >= 10 && request < 20)
            {
                Console.WriteLine("{0} 处理请求 {1}", this.GetType().Name, request);
            }
            else if (base.successor != null)
            {
                successor.HandleRequest(request);
            }
        }
    }

    /// <summary>
    /// 处理者类3
    /// </summary>
    class ConcreteHandlerThree : Handler
    {
        public override void HandleRequest(int request)
        {
            if (request >= 20 && request < 30)
            {
                Console.WriteLine("{0} 处理请求 {1}", this.GetType().Name, request);
            }
            else if (successor != null)
            {
                successor.HandleRequest(request);
            }
        }
    }