BufferBase

BufferBaseLib.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;

namespace BufferBaseLib
{
    public interface IBufferState
    {
        void Commit();
    }

    public interface IBuffer
    {
        IBufferState CaptureState();
    }

    public abstract class BufferBase<T> : IBuffer
    {
        private readonly object _gate = new object();
        private List<T> _items;

        public class BufferState : IBufferState
        {
            private BufferBase<T> _buffer;
            private IList<T> _items;

            public BufferState(BufferBase<T> buffer, IList<T> items)
            {
                this._buffer = buffer;
                this._items = items;
            }

            public void Commit()
            {
                if (this._items.Count > 0) 
                {
                    this._buffer.Flush(this._items);
                }
            }
        }

        public void Add(T item)
        {
            lock (_gate)
            {
                if (_items == null)
                {
                    _items = new List<T>();
                }

                _items.Add(item);
            }
        }

        public IBufferState CaptureState()
        {
            List<T> items;
            lock (_gate)
            {
                items = _items;
                _items = null;
            }
            return new BufferState(this, items);
        }

        protected abstract void Flush(IList<T> items);
    }

    public class LogBuffer : BufferBase<string> 
    {
        protected override void Flush(IList<string> items)
        {
            foreach (string item in items)
            {
                Console.WriteLine("LogBuffer Flush:{0}", item);
            }
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            LogBuffer logBuff = new LogBuffer();

            new Thread(() =>
            {
                while (true)
                {
                    logBuff.Add(string.Format("add thread 1: {0}", DateTime.Now));
                    Thread.Sleep(100);
                }
            }).Start();

            new Thread(() =>
            {
                while (true)
                {
                    logBuff.Add(string.Format("add thread 2: {0}", DateTime.Now));
                    Thread.Sleep(100);
                }
            }).Start();

            new Thread(() =>
            {
                while (true)
                {
                    logBuff.CaptureState().Commit();
                    Thread.Sleep(1000);
                }
            }).Start();

            Console.ReadKey();
        }
    }
}

简化了一下

// 去掉所有接口，只用一个BufferBase基类就够了，Flush(IList<T>)方法当做模板方法，新增一个Flush()
// 库的扩展者只需要继承BufferBase，重写模板方法就行了
// 库的使用者只有Add和Flush两个接口，屏蔽掉CaptureState这些细节，防止用户调用了CaptureState没调用Commit，丢了日志
using System;
using System.Collections.Generic;
using System.Text;
using System.Threading;

namespace BufferBaseLib
{

    public abstract class BufferBase<T>
    {
        private readonly object _gate = new object();
        private List<T> _items;

        public void Add(T item)
        {
            lock (_gate)
            {
                if (_items == null)
                {
                    _items = new List<T>();
                }

                _items.Add(item);
            }
        }

        public void Flush()
        {
            List<T> items;
            lock (_gate)
            {
                items = _items;
                _items = null;
            }
            this.Flush(items);
        }

        protected abstract void Flush(IList<T> items);
    }

    public class LogBuffer : BufferBase<string> 
    {
        protected override void Flush(IList<string> items)
        {
            foreach (string item in items)
            {
                Console.WriteLine("LogBuffer Flush:{0}", item);
            }
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            LogBuffer logBuff = new LogBuffer();

            new Thread(() =>
            {
                while (true)
                {
                    logBuff.Add(string.Format("add thread 1: {0}", DateTime.Now));
                    Thread.Sleep(100);
                }
            }).Start();

            new Thread(() =>
            {
                while (true)
                {
                    logBuff.Add(string.Format("add thread 2: {0}", DateTime.Now));
                    Thread.Sleep(100);
                }
            }).Start();

            new Thread(() =>
            {
                while (true)
                {
                    logBuff.Flush();
                    Thread.Sleep(1000);
                }
            }).Start();

            Console.ReadKey();
        }
    }
}