Refine .Net Core Memory cache

Fix errors in xml comments, refactor the configuration logic and test it
more thoroughly.

Author: fredericDelaporte

CoreMemoryCache/NHibernate.Caches.CoreMemoryCache.Tests/CoreMemoryCacheSectionHandlerFixture.cs

@@ -41,25 +41,35 @@ public void TestGetConfigNullSection()
 			var handler = new CoreMemoryCacheSectionHandler();
 			var section = new XmlDocument();
 			var result = handler.Create(null, null, section);
-			Assert.That(result, Is.Not.Null);
-			Assert.IsTrue(result is CacheConfig[]);
-			var caches = result as CacheConfig[];
-			Assert.That(caches.Length, Is.EqualTo(0));
+			Assert.That(result, Is.Not.Null, "result");
+			Assert.That(result, Is.InstanceOf<CacheConfig>());
+			var config = (CacheConfig) result;
+			Assert.That(config.ExpirationScanFrequency, Is.Null, "ExpirationScanFrequency");
+			Assert.That(config.Regions, Is.Not.Null, "Regions");
+			Assert.That(config.Regions.Length, Is.EqualTo(0));
 		}
 
 		[Test]
 		public void TestGetConfigFromFile()
 		{
-			const string xmlSimple = "<corememorycache><cache region=\"foo\" expiration=\"500\" sliding=\"true\" /></corememorycache>";
+			const string xmlSimple =
+				"<corememorycache expiration-scan-frequency=\"5\"><cache region=\"foo\" expiration=\"500\" sliding=\"true\" /></corememorycache>";
 
 			var handler = new CoreMemoryCacheSectionHandler();
 			var section = GetConfigurationSection(xmlSimple);
 			var result = handler.Create(null, null, section);
 			Assert.That(result, Is.Not.Null);
-			Assert.IsTrue(result is CacheConfig[]);
-			var caches = result as CacheConfig[];
-			Assert.That(caches.Length, Is.EqualTo(1));
-			Assert.That(caches[0].Properties, Does.ContainKey("cache.use_sliding_expiration"));
+			Assert.That(result, Is.InstanceOf<CacheConfig>());
+			var config = (CacheConfig) result;
+			Assert.That(config.ExpirationScanFrequency, Is.EqualTo("5"), "ExpirationScanFrequency");
+
+			Assert.That(config.Regions, Is.Not.Null, "Regions");
+			Assert.That(config.Regions.Length, Is.EqualTo(1), "Regions count");
+			Assert.That(config.Regions[0].Region, Is.EqualTo("foo"));
+			Assert.That(config.Regions[0].Properties, Does.ContainKey("cache.use_sliding_expiration"));
+			Assert.That(config.Regions[0].Properties["cache.use_sliding_expiration"], Is.EqualTo("true"));
+			Assert.That(config.Regions[0].Properties, Does.ContainKey("expiration"));
+			Assert.That(config.Regions[0].Properties["expiration"], Is.EqualTo("500"));
 		}
 	}
 }

CoreMemoryCache/NHibernate.Caches.CoreMemoryCache/CacheConfig.cs

@@ -3,27 +3,40 @@
 namespace NHibernate.Caches.CoreMemoryCache
 {
 	/// <summary>
-	/// Cache config properties.
+	/// Cache configuration properties.
 	/// </summary>
 	public class CacheConfig
 	{
 		/// <summary>
-		/// Build a cache global configuration.
+		/// Build a cache configuration.
 		/// </summary>
 		/// <param name="expirationScanFrequency">The frequency at which scans for cleaning expired cached item have to be done.</param>
-		public CacheConfig(string expirationScanFrequency)
+		/// <param name="regions">The configured cache regions.</param>
+		public CacheConfig(string expirationScanFrequency, RegionConfig[] regions)
 		{
 			ExpirationScanFrequency = expirationScanFrequency;
-			Global = true;
+			Regions = regions;
 		}
 
+		/// <summary>The frequency at which scans for cleaning expired cached item have to be done.</summary>
+		public string ExpirationScanFrequency { get; }
+
+		/// <summary>The configured cache regions.</summary>
+		public RegionConfig[] Regions { get; }
+	}
+
+	/// <summary>
+	/// Cache region configuration properties.
+	/// </summary>
+	public class RegionConfig
+	{
 		/// <summary>
 		/// Build a cache region configuration.
 		/// </summary>
 		/// <param name="region">The configured cache region.</param>
 		/// <param name="expiration">The expiration for the region.</param>
 		/// <param name="sliding">Whether the expiration should be sliding or not.</param>
-		public CacheConfig(string region, string expiration, string sliding)
+		public RegionConfig(string region, string expiration, string sliding)
 		{
 			Region = region;
 			Properties = new Dictionary<string, string>();
@@ -33,15 +46,9 @@ public CacheConfig(string region, string expiration, string sliding)
 				Properties["cache.use_sliding_expiration"] = sliding;
 		}
 
-		/// <summary>Whether this configuration is global or is a cache region configuration.</summary>
-		public bool Global { get; }
-
 		/// <summary>The region name.</summary>
 		public string Region { get; }
 
-		/// <summary>The frequency at which scans for cleaning expired cached item have to be done.</summary>
-		public string ExpirationScanFrequency { get; }
-
 		/// <summary>The configuration properties.</summary>
 		public IDictionary<string,string> Properties { get; }
 	}

CoreMemoryCache/NHibernate.Caches.CoreMemoryCache/CoreMemoryCacheProvider.cs

@@ -36,6 +36,7 @@ public class CoreMemoryCacheProvider : ICacheProvider
 	{
 		private static readonly Dictionary<string, IDictionary<string, string>> ConfiguredCachesProperties;
 		private static readonly INHibernateLogger Log;
+
 		/// <summary>
 		/// The frequency at which scans for cleaning expired cached item have to be done. By default, its value is
 		/// initialized from <c>expiration-scan-frequency</c> attribute of the <c>corememorycache</c> configuration
@@ -49,7 +50,7 @@ public class CoreMemoryCacheProvider : ICacheProvider
 		/// For this property to be taken into account, it must be set before any cache is built.
 		/// </para>
 		/// <para>
-		/// If <c>cache.expiration_scan_frequency</c> is provided as an integer, this integer will be used as a number
+		/// If <c>expiration-scan-frequency</c> is provided as an integer, this integer will be used as a number
 		/// of minutes. Otherwise the setting will be parsed as a <see cref="TimeSpan" />.
 		/// </para>
 		/// </remarks>
@@ -60,26 +61,23 @@ static CoreMemoryCacheProvider()
 			Log = NHibernateLogger.For(typeof(CoreMemoryCacheProvider));
 			ConfiguredCachesProperties = new Dictionary<string, IDictionary<string, string>>();
 
-			if (!(ConfigurationManager.GetSection("corememorycache") is CacheConfig[] list))
+			if (!(ConfigurationManager.GetSection("corememorycache") is CacheConfig config))
 				return;
-			foreach (var cache in list)
+
+			if (config.ExpirationScanFrequency != null)
 			{
-				if (cache.Global)
-				{
-					if (cache.ExpirationScanFrequency != null)
-					{
-						if (int.TryParse(cache.ExpirationScanFrequency, out var minutes))
-							ExpirationScanFrequency = TimeSpan.FromMinutes(minutes);
-						else if (TimeSpan.TryParse(cache.ExpirationScanFrequency, out var expirationScanFrequency))
-							ExpirationScanFrequency = expirationScanFrequency;
-						if (!ExpirationScanFrequency.HasValue)
-							Log.Warn(
-								"Invalid value '{0}' for cache.expiration_scan_frequency setting: it is neither an int nor a TimeSpan. Ignoring.",
-								cache.ExpirationScanFrequency);
-					}
-					continue;
-				}
+				if (int.TryParse(config.ExpirationScanFrequency, out var minutes))
+					ExpirationScanFrequency = TimeSpan.FromMinutes(minutes);
+				else if (TimeSpan.TryParse(config.ExpirationScanFrequency, out var expirationScanFrequency))
+					ExpirationScanFrequency = expirationScanFrequency;
+				if (!ExpirationScanFrequency.HasValue)
+					Log.Warn(
+						"Invalid value '{0}' for expiration-scan-frequency setting: it is neither an int nor a TimeSpan. Ignoring.",
+						config.ExpirationScanFrequency);
+			}
 
+			foreach (var cache in config.Regions)
+			{
 				ConfiguredCachesProperties.Add(cache.Region, cache.Properties);
 			}
 		}
@@ -94,7 +92,8 @@ public ICache BuildCache(string regionName, IDictionary<string, string> properti
 				regionName = string.Empty;
 			}
 
-			if (ConfiguredCachesProperties.TryGetValue(regionName, out var configuredProperties) && configuredProperties.Count > 0)
+			if (ConfiguredCachesProperties.TryGetValue(regionName, out var configuredProperties) &&
+				configuredProperties.Count > 0)
 			{
 				if (properties != null)
 				{
@@ -130,8 +129,9 @@ public ICache BuildCache(string regionName, IDictionary<string, string> properti
 					sb.Append(";");
 				}
 
-				Log.Debug("building cache with region: {0}, properties: {1}" , regionName, sb.ToString());
+				Log.Debug("building cache with region: {0}, properties: {1}", regionName, sb.ToString());
 			}
+
 			return new CoreMemoryCache(regionName, properties);
 		}
 

CoreMemoryCache/NHibernate.Caches.CoreMemoryCache/CoreMemoryCacheSectionHandler.cs

@@ -19,49 +19,30 @@ public class CoreMemoryCacheSectionHandler : IConfigurationSectionHandler
 		/// <param name="parent"></param>
 		/// <param name="configContext"></param>
 		/// <param name="section"></param>
-		/// <returns>An array of CacheConfig objects.</returns>
+		/// <returns>A <see cref="CacheConfig" /> object.</returns>
 		public object Create(object parent, object configContext, XmlNode section)
 		{
-			var caches = new List<CacheConfig>();
+			var caches = new List<RegionConfig>();
 
-			var esf = section.Attributes?["expiration-scan-frequency"];
-			if (esf != null)
-			{
-				caches.Add(new CacheConfig(esf.Value));
-			}
-			
 			var nodes = section.SelectNodes("cache");
 			foreach (XmlNode node in nodes)
 			{
-				string region = null;
-				string expiration = null;
-				string sliding = null;
-				var r = node.Attributes["region"];
-				var e = node.Attributes["expiration"];
-				var s = node.Attributes["sliding"];
-				if (r != null)
-				{
-					region = r.Value;
-				}
-				if (e != null)
-				{
-					expiration = e.Value;
-				}
-				if (s != null)
-				{
-					sliding = s.Value;
-				}
+				var region = node.Attributes["region"]?.Value;
+				var expiration = node.Attributes["expiration"]?.Value;
+				var sliding = node.Attributes["sliding"]?.Value;
 				if (region != null)
 				{
-					caches.Add(new CacheConfig(region, expiration, sliding));
+					caches.Add(new RegionConfig(region, expiration, sliding));
 				}
 				else
 				{
-					Log.Warn("Found a cache node lacking a region name: ignored. Node: {0}",
+					Log.Warn("Found a cache region node lacking a region name: ignored. Node: {0}",
 						node.OuterXml);
 				}
 			}
-			return caches.ToArray();
+
+			var esf = section.Attributes?["expiration-scan-frequency"]?.Value;
+			return new CacheConfig(esf, caches.ToArray());
 		}
 
 		#endregion