/// <summary>
/// 注册一个新缓存项
/// </summary>
/// <param name="item">缓存项</param>
/// <returns>是否注册成功</returns>
public bool Add(string key, TimeSpan expire, bool isSlidingExpiration, RefreshLocalCacheItem refresh, RefreshLocalCacheItemFail refreshFail)
{
LocalCacheItem item = new LocalCacheItem()
{
Key = key,
Value = null,
Expire = expire,
IsSlidingExpiration = isSlidingExpiration,
RefreshTime = DateTime.MinValue,
Refresh = refresh,
RefreshFail = refreshFail
};
using (Lock.WriteLock)
{
if (this.CacheItems.ContainsKey(item.Key))
{
if (IsAddOverWriteSameKeyValue)
{
this.CacheItems[item.Key] = item;
}
else
{
return(false);
}
}
else
{
this.CacheItems.Add(item.Key, item);
}
}
return(true);
}
/// <summary>
/// 获取缓存项
/// </summary>
/// <param name="key">缓存项键</param>
/// <returns></returns>
public LocalCacheItem GetCacheItem(string key)
{
DateTime nowTime = DateTime.Now;
LocalCacheItem item = null;
using (Lock.ReadLock)
{
if (CacheItems.TryGetValue(key, out item) && item != null) //缓存项存在的情况
{
if (item.RefreshTime.Add(item.Expire) < nowTime) //过期了
{
object newValue = null;
Exception exception = null;
try
{
newValue = item.Refresh(item.Key);
}
catch (Exception ex)
{
exception = ex;
newValue = null;
}
if (newValue != null)
{
item.Value = newValue;
item.RefreshTime = nowTime;
}
else
{
if (item.RefreshFail != null)
{
if (!item.RefreshFail(item, exception))
{
return(null);
}
}
else if (!ContinueUseLocalCacheWhenRefeshFail)
{
return(null);
}
}
}
else//没过期
{
if (item.IsSlidingExpiration)//滑动过期
{
item.RefreshTime = nowTime;
}
}
}
else//缓存项根本就没有
{
return(null);
}
}
return(item);
}
/// <summary>
/// 获取缓存项值
/// </summary>
/// <param name="key">缓存项键</param>
/// <returns></returns>
public object Get(string key)
{
LocalCacheItem item = GetCacheItem(key);
if (item != null)
{
return(item.Value);
}
return(null);
}