自定义缓存

今天由于工作的原因,需要在WCF在用到缓存,但发现WCF没有现成的缓存类,这可能是我用WCF的时间比较短.所以我自己写了一个缓存类.

写的比较简单,但对于项目于那个功能已经够用了.

自定义的缓存功能由两个类和一个委托组成:

CacheValue:用于存储缓存值

Cache:通过HashSet组织缓存项(HashSet自身具有线程安全性)

CacheTimeOut:超时后触发

CacheTimeOut:

public delegate void CacheTimeOut(CacheValue obj);

CacheValue:

public class CacheValue
    {
        public event CacheTimeOut TimeOutHandler;
        /// <summary>
        /// 上次调用时间
        /// </summary>
        private DateTime lastTime;

        private int _expired = 1800;


        private System.Timers.Timer timer = new System.Timers.Timer();

        /// <summary>
        /// Key
        /// </summary>
        public string Key { get; set; }

        /// <summary>
        /// 值
        /// </summary>
        private object _value;
        public object Value
        {
            get
            {

                lastTime = DateTime.Now;
                return _value;
            }
            set
            {
                lastTime = DateTime.Now;

                _value = value;
            }
        }
        /// <summary>
        /// 过期时间
        /// </summary>
        public int Expired
        {
            get { return _expired; }
            set { _expired = value; }
        }
        public CacheValue()
        {
            Init();
        }
        public CacheValue(object val)
        {
            this.Value = val;
            Init();
        }
        public CacheValue(object val, int expired)
        {
            this.Value = val;
            this.Expired = expired;
            Init();
        }
        /// <summary>
        /// 初始化
        /// </summary>
        private void Init()
        {

            timer.Elapsed += new System.Timers.ElapsedEventHandler(timer_Elapsed);
            lastTime = DateTime.Now;
            timer.Start();
            timer.Interval = 1000;
        }

        void timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            if (this.Expired < 0)
            { return; }
            DateTime now = DateTime.Now;
            TimeSpan span = now - lastTime;

            if (span.Seconds >= Expired)
            {
                if (TimeOutHandler != null)
                {
                    TimeOutHandler(this);
                }
            }
        }
    }

Cache:

public class Cache
    {
        public object objKey = new object();
        private HashSet<CacheValue> hashCache = new HashSet<CacheValue>();
        public HashSet<CacheValue> Caches
        {
            get { return hashCache; }
        }
        public CacheValue this[string key]
        {
            set
            {
                if (string.IsNullOrEmpty(key))
                {
                    return;
                }
                lock (objKey)
                {
                    CacheValue val = hashCache.SingleOrDefault(t => t.Key == key);
                    if (val != null)
                        hashCache.Remove(val);
                    val = value;
                    val.Key = key;
                    val.TimeOutHandler += new CacheTimeOut(val_TimeOutHandler);
                    hashCache.Add(val);
                }
            }
            get
            {
                if (string.IsNullOrEmpty(key))
                {
                    return null; ;
                }
                return hashCache.SingleOrDefault(t => t.Key == key);
            }
        }

        void val_TimeOutHandler(CacheValue obj)
        {
            hashCache.Remove(obj);
        }
        public bool Remove(string key)
        {
            CacheValue val = hashCache.SingleOrDefault(t => t.Key == key);
            if (val != null)
            {
                return hashCache.Remove(val);
            }
            else
            {
                return true;
            }
        }

        public void Clear()
        {
            hashCache.Clear();
        }
    }

测试:

Cache cache = new Cache();
        private void btn_Click(object sender, EventArgs e)
        {
            Thread[] ths = new Thread[10];
            for (int i = 0; i < ths.Length; i++)
            {
                ths[i] = new Thread(new ParameterizedThreadStart(AddCacheItem));
            }
            foreach (Thread th in ths)
            {
                th.Start();
            }
        }

        private void AddCacheItem(object obj)
        {
            for (int i = 0; i < 20; i++)
            {
                cache[i.ToString()] = new CacheValue(i, i);
            }
        }

        private void btnRead_Click(object sender, EventArgs e)
        {
            Thread th = new Thread(new ParameterizedThreadStart(ReadCache));
            th.Start();
        }


        private void ReadCache(object obj)
        {
            Random random = new Random();
            string key;
            while (cache.Caches.Count > 0)
            {
                key = random.Next(19).ToString();
                CacheValue val = cache[key];
                if (val != null)
                {
                    Trace.WriteLine(val.Value);
                }
            }
        }

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