Generic Delegate

 

<Implementation>   

 

 public delegate void Printer<T>(T data);

    public static class BufferExtension
    {
        public static void Dump<T>(this IBuffer<T> buffer, Printer<T> print)
        {
            foreach (var item in buffer)
            {
                print(item);
            }

        }

}

  

 

Action , Func , Predicate

Action : 적어도 한개 이상의 generic parameter를 갖고 void return 

Fcun : 적어도 한개 이상의 generic parameter를 갖고 마지막 generic parameter의 형태로 return 한다.

Predicate : 한개의 generic parameter를 갖고 bool 타입의 return 을 한다.

 

            printBool(isLessThanTen(sqare(add(3, 5))));
            {
                Console.WriteLine("My action print");
            };
            myprint();

            Action<bool> printBool = d => Console.WriteLine(d);
            Func<double, double> sqare = d => d * d;
            Func<double, double,double > add = (x, y) => x + y;
            Predicate<double> isLessThanTen = d => d < 10;

            printBool(isLessThanTen(sqare(add(3, 5))));

 

 

Generic Event Handler

 

public class CircularBuffer<T>  : Buffer<T>
    {
        int _capacity;
        public CircularBuffer(int capacity = 10)
        {
            _capacity = capacity;
        }

        public override void Write(T value)
        {
            base.Write(value);
            if (_queue.Count > _capacity)
            {

                var discard = _queue.Dequeue();
                OnItemDiscarded(discard, value);
            }
        }

        private void OnItemDiscarded(T discard, T value)
        {
            if(ItemDiscarded != null)
            {
                var args = new ItemDiscardedEventArgs<T>(discard, value);
                ItemDiscarded(this, args);
            }
        }

        public event EventHandler<ItemDiscardedEventArgs<T>> ItemDiscarded;
        public bool IsFull { get { return _queue.Count == _capacity; } }

    }

 

    public class ItemDiscardedEventArgs<T> : EventArgs
    {
        public ItemDiscardedEventArgs(T discard, T newitem)
        {
            ItemDiscarded = discard;
            NewItem = newitem;
        }
        public T ItemDiscarded { get; set; }
        public T NewItem { get; set; }
    }

 

 

[Impementation] 

 

static void Main(string[] args)
        {           
            var buffer = new CircularBuffer<double>(capacity:3);
            buffer.ItemDiscarded += ItemDiscarded;           
           
            ProcessInput(buffer);
        
            buffer.Dump(d => Console.WriteLine(d));
           
            ProcessBuffer(buffer);
        }

 

        static void ItemDiscarded(object sender, ItemDiscardedEventArgs<double> e)
        {
            Console.WriteLine("Buffer full. Discarding {0} New item is {1}",
                    e.ItemDiscarded, e.NewItem
                );
        }

       

프로그램 설명 :

 

지정된 용량 3 이상의 값이 buffer에 입력이 되어 삭제되는 buffer 값과 새롭게 입력되는 buffer의 값을 ItemDiscarded event handler를 수행한다.

전달되는 EventArgs 는 generic으로 선언되어 있음.