/// <summary>
/// Remove an entry with a given key. Notifies subscriber, if there is any,
/// of the removed item.
/// </summary>
/// <param name="key"></param>
/// <param name="regionName"></param>
/// <returns></returns>
public override object Remove(string key, string regionName = null)
{
if (key == null)
{
throw new ArgumentNullException("key");
}
var cacheKey = new CacheKey(key);
CacheEntry cacheValue = null;
// remove the item, return if not found.
lock (_locker)
{
var mruEntry = MruManager.GetItem(cacheKey);
if (mruEntry == null)
{
return(null);
}
// get the Store's Current Key containing the TimeStamp!
cacheKey = (CacheKey)mruEntry.Key;
cacheValue = mruEntry.Value as CacheEntry;
MruManager.Remove(cacheKey);
}
// Notify the subscriber of the removed item.
if (CacheEntrySetRemovedCallback != null)
{
CacheEntrySetRemovedCallback(new[]
{
new CacheEntryRemovedArguments(this, CacheEntryRemovedReason.Removed, cacheValue.Convert(cacheKey))
});
}
return(cacheValue);
}
public override void Set(string key, object value,
CacheItemPolicy policy, string regionName = null)
{
if (key == null)
{
throw new ArgumentNullException("key");
}
if (value == null)
{
throw new ArgumentNullException("value");
}
if (policy == null)
{
policy = DefaultPolicy;
}
var now = GetCurrentDate(0);
var entry = new CacheEntry(policy, now)
{
Value = value
};
var cacheKey = new CacheKey(key)
{
TimeStamp = now
};
lock (_locker)
{
var e = MruManager.GetItem(cacheKey);
if (e == null)
{
MruManager.Add(cacheKey, entry);
return;
}
entry = e.Value as CacheEntry;
entry.Value = value;
// if priotiry is not removable, just update the store w/ value
if (entry.NonExpiring)
{
return;
}
if (!entry.IsExpired(now))
{
// slide the expire time...
if (entry.SlidingExpiration > 0)
{
entry.ExpirationTime = GetCurrentDate(entry.SlidingExpiration);
}
return;
}
// adjust policy (set to slide every 5 mins) of the expired item to accomodate this update...
if (entry.SlidingExpiration == 0)
{
entry.SlidingExpiration = TimeSpan.TicksPerMinute * 5;
}
entry.ExpirationTime = GetCurrentDate(entry.SlidingExpiration);
}
}
public override CacheItem GetCacheItem(string key, string regionName = null)
{
if (key == null)
{
throw new ArgumentNullException("key");
}
MruItem mruEntry = null;
var cacheKey = new CacheKey(key);
// code block to get item from store and if found, return it if not expired.
Func <bool> block = (() =>
{
lock (_locker)
{
// try to get from the store
mruEntry = MruManager.GetItem(cacheKey);
if (mruEntry != null)
{
cacheKey = (CacheKey)mruEntry.Key;
if (IsNotExpired(cacheKey, (CacheEntry)mruEntry.Value, false))
{
return(true);
}
}
return(false);
}
});
if (block())
{
return(new CacheItem(key, mruEntry.Value));
}
#region try to update the Cache entry if it is expired by calling the Update callback.
if (CacheEntrySetUpdateCallback == null)
{
return(null);
}
CacheEntrySetUpdateCallback(new CacheEntryUpdateArguments[] { new CacheEntryUpdateArguments(this, CacheEntryRemovedReason.Expired, key, null) });
// try to get from the store a 2nd time and see if item got updated & no longer expired...
if (block())
{
return(new CacheItem(key, mruEntry.Value));
}
#endregion
return(null);
}
public override bool Contains(string key, string regionName = null)
{
if (key == null)
{
throw new ArgumentNullException("key");
}
var cacheKey = new CacheKey(key);
bool b;
lock (_locker)
{
// try to get from the store
var mruEntry = MruManager.GetItem(cacheKey);
if (mruEntry == null)
{
return(false);
}
cacheKey = (CacheKey)mruEntry.Key;
b = IsNotExpired(cacheKey, (CacheEntry)mruEntry.Value, false);
if (b || CacheEntrySetUpdateCallback == null)
{
return(b);
}
}
// try to update the Cache entry if it is expired by calling the Update callback.
CacheEntrySetUpdateCallback(new CacheEntryUpdateArguments[]
{ new CacheEntryUpdateArguments(this, CacheEntryRemovedReason.Expired, key, null) });
lock (_locker)
{
// try to get from the store a 2nd time and see if item got updated & no longer expired...
var mruEntry = MruManager.GetItem(cacheKey);
if (mruEntry != null)
{
cacheKey = (CacheKey)mruEntry.Key;
b = IsNotExpired(cacheKey, (CacheEntry)mruEntry.Value, false);
}
return(b);
}
}
