public void Set(string key, T item, TimeSpan?expiration = null, CacheUpdateCallback <T> expirationCallback = null)
{
_cache.AddOrUpdate(key, k =>
{
if (expiration.HasValue)
{
_timers.Add(key, GetTimer(key, expiration.Value));
if (expirationCallback != null)
{
_callbacks.Add(key, expirationCallback);
}
}
return(item);
},
(k, e) =>
{
if (_timers.ContainsKey(key))
{
_timers[key].Stop();
if (!expiration.HasValue)
{
_timers.Remove(key);
}
else
{
_timers[key].Interval = expiration.Value.TotalMilliseconds;
_timers[key].Start();
}
}
else if (expiration.HasValue)
{
_timers.Add(key, GetTimer(key, expiration.Value));
}
if (expirationCallback != null)
{
_callbacks[key] = expirationCallback;
}
else if (_callbacks.ContainsKey(key))
{
_callbacks.Remove(key);
}
return(item);
});
}
public T GetOrAdd(string key,
CacheUpdateCallback <T> getValueCallback,
TimeSpan?expiration = null,
CacheUpdateCallback <T> expirationCallback = null)
{
T item;
// first try to get value from the cache
if (_cache.TryGetValue(key, out item))
{
return(item);
}
// then try to get the value from the dedicated callback
if (getValueCallback(out item))
{
Set(key, item, expiration, expirationCallback);
return(item);
}
// if callback report failure avoid updating the cache
return(item);
}
