public static void EnsureIsStarted(Key key,
ICacheItemRecalculationStrategy recalculationStrategy,
MethodInterceptionArgs args,
ICache cache)
{
var keyString = key.ToString();
Ensure.That<NHelpfulException.FrameworkExceptions.ArgumentException>(keyString.Length.IsLessThanOrEqualTo(260),
"key must be less than 260 characters long.");
try
{
bool createdNew;
var mutex = new Mutex(false, MutexPrefix + keyString, out createdNew);
if (createdNew)
{
if (cache[keyString].IsNotNull())
return;
//item already in cache, assume thread already started TODO: possibly log this as an error
ThreadPool.QueueUserWorkItem(
o => recalculationStrategy.RunRoutine(key, args, cache, mutex, args.Proceed));
//NOTE: mutex.ReleaseMutex(); is not called because the mutex is only expected to be released upon closure of the application
}
}
catch (Exception)
{
//log exception
throw;
}
}
/// <remarks>
/// Consider alternatives to instantiating instances
/// of the specified types using Activator.CreateInstance.
/// </remarks>
public override void OnInvoke(MethodInterceptionArgs args)
{
Ensure.That<ArgumentNullException>(args.IsNotNull(), "args");
_cache = (ICache) Activator.CreateInstance(_cacheType);
_keyCreationStrategy = (IFriendlyNameCreationStrategy) Activator.CreateInstance(_keyCreationStrategyType);
if (_recalculationStrategyType.IsNotNull())
{
_recalculationStrategy =
(ICacheItemRecalculationStrategy)
Activator.CreateInstance(_recalculationStrategyType, _durationToRecalculate);
}
var friendlyName = _keyCreationStrategy.GenerateFriendlyName(args);
var key = _durationToStore == default(TimeSpan) //infer from the variables set, the key type to create?
? new Key(DefaultCacheDuration, DefaultCacheExpirationType, friendlyName)
: new Key(_durationToStore, _storageStyle, _expirationType, friendlyName);
object cacheItem;
if ((cacheItem = _cache[key.ToString()]).IsNotNull())
{
args.ReturnValue = cacheItem;
}
else
{
args.Proceed();
_cache.Add(key, args.ReturnValue);
if (_recalculationStrategy.IsNotNull())
AsyncCacheItemRecalculator.EnsureIsStarted(key, _recalculationStrategy, args, _cache);
}
}
