/// <summary>
/// Gets an object from the cache or creates it if it doesnt exist
/// </summary>
/// <param name="key">key to item</param>
/// <param name="expire">Expire this item after this much time. -1 for NEVER</param>
/// <param name="f">Factory method if key doesnt exist</param>
/// <returns></returns>
public object Get(string key, TimeSpan expire, Func <object> f)
{
CacheItem item = backend.Get(key);
if (item == null)
{
if (f != null)
{
object val = f();
item = new CacheItem(key, val);
// anything less than 0 is NEVER
if (expire.Ticks < 0)
{
item.Stats.Expire = DateTime.MaxValue;
}
else
{
item.Stats.Expire = item.Stats.Created + expire;
}
backend.Set(item);
}
}
if (item == null)
{
return(null);
}
// item is expired..
if (item.Stats.Expire <= DateTime.Now)
{
// recreate it..
if (f != null)
{
object val = f();
item = new CacheItem(key, val);
backend.Set(item);
}
}
// anything less than 0 is NEVER
if (expire.Ticks < 0)
{
item.Stats.Expire = DateTime.MaxValue;
}
else
{
item.Stats.Expire = item.Stats.Created + expire;
}
// update access statistics for the item
backend.Touch(item);
return(item.Value);
}
