C# CacheItem类代码示例

 public Bitmap this[ScannedImage scannedImage]
 {
     get
     {
         var newState = scannedImage.GetThumbnailState();
         if (cache.ContainsKey(scannedImage))
         {
             // Cache hit
             var item = cache[scannedImage];
             if (item.State != newState)
             {
                 // Invalidated
                 item.Thumbnail.Dispose();
                 item.Thumbnail = scannedImage.GetThumbnail(userConfigManager.Config.ThumbnailSize);
                 item.State = newState;
             }
             return item.Thumbnail;
         }
         else
         {
             // Cache miss
             var item = new CacheItem
             {
                 Thumbnail = scannedImage.GetThumbnail(userConfigManager.Config.ThumbnailSize),
                 State = newState
             };
             return item.Thumbnail;
         }
     }
 }

        /// <summary>
        /// Initializes a new instance of the ImageListViewCacheManager class.
        /// </summary>
        /// <param name="owner">The owner control.</param>
        public ImageListViewCacheManager(ImageListView owner)
        {
            lockObject = new object();

            mImageListView = owner;
            mCacheMode = CacheMode.OnDemand;
            mCacheLimitAsItemCount = 0;
            mCacheLimitAsMemory = 20 * 1024 * 1024;
            mRetryOnError = owner.RetryOnError;

            toCache = new Stack<CacheItem>();
            thumbCache = new Dictionary<Guid, CacheItem>();
            editCache = new Dictionary<Guid, Image>();

            rendererToCache = new Stack<CacheItem>();
            rendererGuid = new Guid();
            rendererItem = null;

            memoryUsed = 0;
            memoryUsedByRemoved = 0;
            removedItems = new List<Guid>();

            mThread = new Thread(new ThreadStart(DoWork));
            mThread.IsBackground = true;

            stopping = false;
            stopped = false;
            disposed = false;

            mThread.Start();
            while (!mThread.IsAlive) ;
        }

 public StoreOperation(StoreMode mode, string key, CacheItem value, uint expires)
     : base(key)
 {
     this.mode = mode;
     this.value = value;
     this.expires = expires;
 }

        public void CanScavengeInBackground()
        {
            CacheItem item1 = new CacheItem("key1", "value1", CacheItemPriority.Low, null);
            CacheItem item2 = new CacheItem("key2", "value2", CacheItemPriority.Normal, null);
            CacheItem item3 = new CacheItem("key3", "value3", CacheItemPriority.High, null);

            AddCacheItem("key1", item1);
            AddCacheItem("key2", item2);
            AddCacheItem("key3", item3);

            TestConfigurationContext context = new TestConfigurationContext();
            CachingConfigurationView view = new CachingConfigurationView(context);
            view.GetCacheManagerSettings().CacheManagers["test"].MaximumElementsInCacheBeforeScavenging = 2;
            view.GetCacheManagerSettings().CacheManagers["test"].NumberToRemoveWhenScavenging = 1;

            CacheCapacityScavengingPolicy scavengingPolicy = new CacheCapacityScavengingPolicy("test", view);
            ScavengerTask scavenger = new ScavengerTask("test", view, scavengingPolicy, this);
            BackgroundScheduler scheduler = new BackgroundScheduler(null, scavenger);
            scheduler.Start();

            Thread.Sleep(500);
            scheduler.StartScavenging();
            Thread.Sleep(250);

            scheduler.Stop();
            Thread.Sleep(250);

            Assert.AreEqual("key1", scavengedKeys);
        }

 public void CallbackReasonScavengedIsGivenToCallbackMethod()
 {
     CacheItem emptyCacheItem = new CacheItem("key", null, CacheItemPriority.Low, new MockRefreshAction());
     RefreshActionInvoker.InvokeRefreshAction(emptyCacheItem, CacheItemRemovedReason.Scavenged, instrumentationProvider);
     Thread.Sleep(100);
     Assert.AreEqual(CacheItemRemovedReason.Scavenged, callbackReason);
 }

 public void RemovedValueCanBeNullDuringCallback()
 {
     CacheItem emptyCacheItem = new CacheItem("key", null, CacheItemPriority.Low, new MockRefreshAction());
     RefreshActionInvoker.InvokeRefreshAction(emptyCacheItem, CacheItemRemovedReason.Expired, instrumentationProvider);
     Thread.Sleep(100);
     Assert.IsNull(removedValue);
 }

 public void RemovedValueIsGivenToCallbackMethod()
 {
     CacheItem emptyCacheItem = new CacheItem("key", "value", CacheItemPriority.Low, new MockRefreshAction());
     RefreshActionInvoker.InvokeRefreshAction(emptyCacheItem, CacheItemRemovedReason.Expired, instrumentationProvider);
     Thread.Sleep(100);
     Assert.AreEqual("value", removedValue);
 }

        /// <summary>
        /// Adds new item to persistence store
        /// </summary>
        /// <param name="storageKey">Unique key for storage item.</param>
        /// <param name="newItem">Item to be added to cache. May not be null.</param>
        protected override void AddNewItem(int storageKey,
                                           CacheItem newItem)
        {
            string key = newItem.Key;
            byte[] valueBytes = SerializationUtility.ToBytes(newItem.Value);
            if (encryptionProvider != null)
            {
                valueBytes = encryptionProvider.Encrypt(valueBytes);
            }

            byte[] expirationBytes = SerializationUtility.ToBytes(newItem.GetExpirations());
            byte[] refreshActionBytes = SerializationUtility.ToBytes(newItem.RefreshAction);
            CacheItemPriority scavengingPriority = newItem.ScavengingPriority;
            DateTime lastAccessedTime = newItem.LastAccessedTime;

            DbCommand insertCommand = database.GetStoredProcCommand("AddItem");
            database.AddInParameter(insertCommand, "@partitionName", DbType.String, partitionName);
            database.AddInParameter(insertCommand, "@storageKey", DbType.Int32, storageKey);
            database.AddInParameter(insertCommand, "@key", DbType.String, key);
            database.AddInParameter(insertCommand, "@value", DbType.Binary, valueBytes);
            database.AddInParameter(insertCommand, "@expirations", DbType.Binary, expirationBytes);
            database.AddInParameter(insertCommand, "@refreshAction", DbType.Binary, refreshActionBytes);
            database.AddInParameter(insertCommand, "@scavengingPriority", DbType.Int32, scavengingPriority);
            database.AddInParameter(insertCommand, "@lastAccessedTime", DbType.DateTime, lastAccessedTime);

            database.ExecuteNonQuery(insertCommand);
        }

        public void Should_dispose_existing_phoenix()
        {
            var key = "theCacheKey" + Guid.NewGuid();
            // Arrange
            var objCacheItem = new CacheItem
            {
                MaxAge = 5,
                StaleWhileRevalidate = 5,
                StoreId = 1000,
                CreatedTime = DateTime.UtcNow.AddSeconds(-5).AddMilliseconds(-1),
                Key = key
            };

            var existingPhoenix = Substitute.For<Phoenix>(Substitute.For<_IInvocation>(), objCacheItem);

            var att = new OutputCacheAttributeWithPublicMethods { Duration = 5, CacheStoreId = 1000, StaleWhileRevalidate = 5 };

            Global.Cache.PhoenixFireCage[key] = existingPhoenix;

            // Action
            att.CreatePhoenixPublic(Substitute.For<_IInvocation>(), objCacheItem);

            // Assert
            Assert.That(Global.Cache.PhoenixFireCage[key] is Phoenix);
            existingPhoenix.Received(1).Dispose();
        }

        protected override bool ProcessResponse(BinaryResponse response)
        {
            if (response.StatusCode == 0)
            {
                int flags = BinaryConverter.DecodeInt32(response.Extra, 0);
                this.result = new CacheItem((ushort)flags, response.Data);
                this.Cas = response.CAS;

            #if EVEN_MORE_LOGGING
                if (log.IsDebugEnabled)
                    log.DebugFormat("Get succeeded for key '{0}'.", this.Key);
            #endif

                return true;
            }

            this.Cas = 0;

            #if EVEN_MORE_LOGGING
            if (log.IsDebugEnabled)
                log.DebugFormat("Get failed for key '{0}'. Reason: {1}", this.Key, Encoding.ASCII.GetString(response.Data.Array, response.Data.Offset, response.Data.Count));
            #endif

            return false;
        }

        public void CanAddMinimalCacheItemToStoreWithItemNotPresent()
        {
            CacheItem cacheItem = new CacheItem("key", new SerializableClass(13), CacheItemPriority.Low, null);
            backingStore.Add(cacheItem);

            Assert.AreEqual(1, backingStore.Count);
        }

        public void SizeNotZeroWhenOneItemInserted()
        {
            CacheItem itemToStore = new CacheItem("key", "value", CacheItemPriority.NotRemovable, null);

            backingStore.Add(itemToStore);
            Assert.AreEqual(1, backingStore.Count, "Inserted item should be in Isolated Storage");
        }

        protected override IOperationResult ProcessResponse(BinaryResponse response)
        {
            var status = response.StatusCode;
            var result = new BinaryOperationResult();

            this.StatusCode = status;

            if (status == 0)
            {
                int flags = BinaryConverter.DecodeInt32(response.Extra, 0);
                this.result = new CacheItem((ushort)flags, response.Data);
                this.Cas = response.CAS;

            #if EVEN_MORE_LOGGING
                if (log.IsDebugEnabled)
                    log.DebugFormat("Get succeeded for key '{0}'.", this.Key);
            #endif

                return result.Pass();
            }

            this.Cas = 0;

            #if EVEN_MORE_LOGGING
            if (log.IsDebugEnabled)
                log.DebugFormat("Get failed for key '{0}'. Reason: {1}", this.Key, Encoding.ASCII.GetString(response.Data.Array, response.Data.Offset, response.Data.Count));
            #endif

            var message = ResultHelper.ProcessResponseData(response.Data);
            return result.Fail(message);
        }

 private byte[] GetThumbnailInternal(string key, object item,
                                     DlnaMediaTypes type, ref int width,
                                     ref int height)
 {
   var thumbnailers = thumbers[type];
   var rw = width;
   var rh = height;
   foreach (var thumber in thumbnailers) {
     try {
       using (var i = thumber.GetThumbnail(item, ref width, ref height)) {
         var rv = i.ToArray();
         lock (cache) {
           cache[key] = new CacheItem(rv, rw, rh);
         }
         return rv;
       }
     }
     catch (Exception ex) {
       Debug(String.Format(
         "{0} failed to thumbnail a resource", thumber.GetType()), ex);
       continue;
     }
   }
   throw new ArgumentException("Not a supported resource");
 }

 /// <summary>
 ///     Retrieves the binary data of the image from the cache.
 /// </summary>
 /// <param name="item">
 ///     The record that identifies the image in the cache.
 /// </param>
 /// <returns>
 ///     The binary data of the image.
 /// </returns>
 protected override Task<byte[]> GetCacheDataAsync(CacheItem item)
 {
     lock (this.cache)
     {
         return Task.FromResult(this.cache[item]);
     }
 }