System.Web.Caching.Cache.NeedsUpdate C# (CSharp) Method

		bool NeedsUpdate (CacheItem item, CacheItemUpdateReason reason, bool needLock)
		{
			try {
				if (needLock)
					cacheLock.EnterWriteLock ();
				
				if (item == null || item.OnUpdateCallback == null)
					return false;

				object expensiveObject;
				CacheDependency dependency;
				DateTime absoluteExpiration;
				TimeSpan slidingExpiration;
				string key = item.Key;
				CacheItemUpdateCallback updateCB = item.OnUpdateCallback;
				
				updateCB (key, reason, out expensiveObject, out dependency, out absoluteExpiration, out slidingExpiration);
				if (expensiveObject == null)
					return false;

				CacheItemPriority priority = item.Priority;
				CacheItemRemovedCallback removeCB = item.OnRemoveCallback;
				CacheItemRemovedReason whyRemoved;

				switch (reason) {
					case CacheItemUpdateReason.Expired:
						whyRemoved = CacheItemRemovedReason.Expired;
						break;

					case CacheItemUpdateReason.DependencyChanged:
						whyRemoved = CacheItemRemovedReason.DependencyChanged;
						break;

					default:
						whyRemoved = CacheItemRemovedReason.Removed;
						break;
				}
				
				Remove (key, whyRemoved, false, false);
				Insert (key, expensiveObject, dependency, absoluteExpiration, slidingExpiration, priority, removeCB, updateCB, false);
				
				return true;
			} catch (Exception) {
				return false;
			} finally {
				if (needLock) {
					// See comment at the top of the file, above cacheLock declaration
					cacheLock.ExitWriteLock ();
				}
			}
		}