c# LRU实现的缓存类
在网上找到网友中的方法，将其修改整理后，实现了缓存量控制以及时间控制，如果开启缓存时间控制，会降低效率。
定义枚举，移除时使用
public enum RemoveType
{
[Description("超时移除")]
TimeOut,
[Description("超量移除")]
Capacity
}
定义委托，移除时使用
public delegate void RemoveKV<Tkey, TValue>(string cacheName, RemoveEntity<Tkey, TValue> entity);
定义缓存类
public class LRUCache<TKey, TValue>
{
const int DEFAULT_CAPACITY = int.MaxValue;
private int _capacity;
private ReaderWriterLockSlim locker;
private IDictionary<TKey, TValue> dictionary;//数据
private LinkedList<TKey> linkedList;//控制Key的数据
private Dictionary<TKey, LinkedListNode<TKey>> dicLinkIndex = null;//控制删除
private Dictionary<TKey, long> dicRefresh = null;//使用时间
private volatile bool isCheckTime = false;//设置是否监测缓存的时间长度
private long cacheTime = 600;//10分钟
private volatile bool isCheckThread = false;//检查线程启动
private long checkTicks = 0;//换算后的时间
private BlockingCollection<RemoveEntity<TKey, TValue>> removeEntities = null;
public event RemoveKV<TKey, TValue> RemoveEntitiesEvent = null;//移除通知
private DateTime checkTime = DateTime.Now;//结束监测的时间
/// <summary>
/// 设置缓存的时间长度，当前按照秒算
/// 设置时间自动设置属性IsCacheCheckTime=true
/// </summary>
public long CacheTime { get { return cacheTime; } set { cacheTime = value;isCheckTime = true; countTime(); } }
/// <summary>
/// 是否监测时间
/// </summary>
public bool IsCacheCheckTime { get { return isCheckTime; } set { isCheckTime = value; countTime(); } }
/// <summary>
/// cache名称
/// </summary>
public string CacheName { get; set; }
public LRUCache() : this(DEFAULT_CAPACITY) { }
public LRUCache(int capacity)
{
locker = new ReaderWriterLockSlim();
_capacity = capacity > 0 ? capacity : DEFAULT_CAPACITY;
dictionary = new Dictionary<TKey, TValue>();
linkedList = new LinkedList<TKey>();
dicLinkIndex = new Dictionary<TKey, LinkedListNode<TKey>>();
dicRefresh = new Dictionary<TKey, long>();
removeEntities = new BlockingCollection<RemoveEntity<TKey, TValue>>(1000);
countTime();
RemoveNotice();
}
/// <summary>
/// 换算时间;
/// 将秒转换成ticks个数
/// </summary>
private void countTime()
{
checkTicks = 10000000 * cacheTime;
}
/// <summary>
/// 更新时间
/// </summary>
/// <param name="key"></param>
private void Refresh(TKey key)
{
dicRefresh[key] = DateTime.Now.Ticks;
if(!isCheckTime)
{
return;
}
if(!isCheckThread)
{
isCheckThread = true;
Task.Factory.StartNew(() =>
{
double wait = (DateTime.Now - checkTime).TotalSeconds;
if(wait<cacheTime)
{
//如果上次监测到本次监测还未到设置的保持时间，
//则等待该时间差后再检查
double sleep = ((double)cacheTime-wait) * 1000+1;
Thread.Sleep((int)sleep);
}
locker.EnterWriteLock();
try
{
LinkedListNode<TKey> last = null;
long tick;
long curTick = DateTime.Now.Ticks;
last = linkedList.Last;//重后往前找
while (last != null)
{
if (dicRefresh.TryGetValue(last.Value, out tick))
{
if ((curTick - tick) > checkTicks)
{
dicLinkIndex.Remove(last.Value);
dicRefresh.Remove(last.Value);
linkedList.RemoveLast();
RemoveEntity<TKey, TValue> entity = new RemoveEntity<TKey, TValue>() { Key = last.Value, Value = dictionary[last.Value], RemoveType= RemoveType.TimeOut };
removeEntities.Add(entity);
dictionary.Remove(last.Value);
}
else
{
break;
}
}
last = linkedList.Last;
}
}
finally { locker.ExitWriteLock(); }
isCheckThread = false;
checkTime = DateTime.Now;
});
}
}
private void RemoveNotice()
{
Task.Factory.StartNew(() =>
{
while(true)
{
RemoveEntity<TKey, TValue> item=null;
if(removeEntities.TryTake(out item,500))
{
if(this.RemoveEntitiesEvent != null)
{
RemoveEntitiesEvent(CacheName, item);
}
}
}
});
}
public void Set(TKey key, TValue value)
{
locker.EnterWriteLock();
try
{
dictionary[key] = value;
LinkedListNode<TKey> item = null;
if(dicLinkIndex.TryGetValue(key,out item))
{
linkedList.Remove(item);
}
dicLinkIndex[key]= linkedList.AddFirst(key);
if (linkedList.Count > _capacity)
{
dictionary.Remove(linkedList.Last.Value);
dicLinkIndex.Remove(linkedList.Last.Value);
linkedList.RemoveLast();
dicRefresh.Remove(linkedList.Last.Value);
RemoveEntity<TKey, TValue> entity = new RemoveEntity<TKey, TValue>() { Key = linkedList.Last.Value, Value = dictionary[linkedList.Last.Value], RemoveType = RemoveType.Capacity };
removeEntities.Add(entity);
dictionary.Remove(linkedList.Last.Value);
}
Refresh(key);
}
finally { locker.ExitWriteLock(); }
}
public bool TryGet(TKey key, out TValue value)
{
locker.EnterUpgradeableReadLock();
try
{
bool b = dictionary.TryGetValue(key, out value);
if (b)
{
locker.EnterWriteLock();
try
{
linkedList.Remove(key);
linkedList.AddFirst(key);
}
finally { locker.ExitWriteLock(); }
}
Refresh(key);
return b;
}
catch { throw; }
finally { locker.ExitUpgradeableReadLock(); }
}
public void Clear()
{
locker.EnterWriteLock();
try
{
dictionary.Clear();
linkedList.Clear();
dicRefresh.Clear();
dicLinkIndex.Clear();
dicRefresh.Clear();
}
finally
{
locker.ExitWriteLock();
}
}
public bool Remove(TKey key)
{
bool isSucess = false;
locker.EnterWriteLock();
try
{
isSucess = dictionary.Remove(key);
dicRefresh.Remove(key);
LinkedListNode<TKey> item = null;
if (dicLinkIndex.TryGetValue(key, out item))
{
linkedList.Remove(item);
}
}
finally
{
locker.ExitWriteLock();
}
return isSucess;
}
public bool ContainsKey(TKey key)
{
locker.EnterReadLock();
try
{
return dictionary.ContainsKey(key);
}
finally { locker.ExitReadLock(); }
}
public int Count
{
get
{
locker.EnterReadLock();
try
{
return dictionary.Count;
}
finally { locker.ExitReadLock(); }
}
}
public int Capacity
{
get
{
locker.EnterReadLock();
try
{
return _capacity;
}
finally { locker.ExitReadLock(); }
}
set
{
locker.EnterUpgradeableReadLock();
try
{
if (value > 0 && _capacity != value)
{
locker.EnterWriteLock();
try
{
_capacity = value;
while (linkedList.Count > _capacity)
{
linkedList.RemoveLast();
}
}
finally { locker.ExitWriteLock(); }
}
}
finally { locker.ExitUpgradeableReadLock(); }
}
}
public ICollection<TKey> Keys
{
get
{
locker.EnterReadLock();
try
{
return dictionary.Keys;
}
finally { locker.ExitReadLock(); }
}
}
public ICollection<TValue> Values
{
get
{
locker.EnterReadLock();
try
{
return dictionary.Values;
}
finally { locker.ExitReadLock(); }
}
}
}
//最后在定一个异常的实体
public class RemoveEntity<TKey,TValue>
{
public TKey Key { get; set; }
public TValue Value { get; set; }
public RemoveType RemoveType { get; set; }
}
就完成了，测试代码
LRUCache<int, int> cache = new LRUCache<int, int>();
cache.RemoveEntitiesEvent += Cache_RemoveEntitiesEvent;
cache.CacheTime =3;//启动缓存时间
Random random = new Random();
DateTime start= DateTime.Now;
for(int i=0;i<10000000;i++)
{
cache.Set(i,random.Next());
}
Console.WriteLine("时间：" + (DateTime.Now - start).TotalSeconds);
Console.Read();
总共10-12秒；如果屏蔽缓存时间设置，7秒
代码已经传到GIT，地址和上一篇缓存模板一直，整合在同一个项目中。
