Reuse the same generic EmptyMapClass instance across the project

bahusoid · bahusoid · commit cf041dfb09de · 2017-12-08T17:42:47.000+05:30
diff --git a/src/NHibernate/Cfg/MappingSchema/AbstractDecoratable.cs b/src/NHibernate/Cfg/MappingSchema/AbstractDecoratable.cs
@@ -9,7 +9,7 @@ namespace NHibernate.Cfg.MappingSchema
 	[Serializable]
 	public abstract class AbstractDecoratable : IDecoratable
 	{
-		private static readonly IDictionary<string, MetaAttribute> EmptyMetaData = new CollectionHelper.EmptyMapClass<string, MetaAttribute>();
+		private static readonly IDictionary<string, MetaAttribute> EmptyMetaData = CollectionHelper.EmptyDictionary<string, MetaAttribute>();
 
 		[NonSerialized]
 		[XmlIgnore]
diff --git a/src/NHibernate/Cfg/XmlHbmBinding/Binder.cs b/src/NHibernate/Cfg/XmlHbmBinding/Binder.cs
@@ -13,7 +13,7 @@ public abstract class Binder
 		protected static readonly INHibernateLogger log = NHibernateLogger.For(typeof (Binder));
 
 		protected static readonly IDictionary<string, MetaAttribute> EmptyMeta =
-			new CollectionHelper.EmptyMapClass<string, MetaAttribute>();
+			CollectionHelper.EmptyDictionary<string, MetaAttribute>();
 
 		protected readonly Mappings mappings;
 
diff --git a/src/NHibernate/Cfg/XmlHbmBinding/ResultSetMappingBinder.cs b/src/NHibernate/Cfg/XmlHbmBinding/ResultSetMappingBinder.cs
@@ -309,7 +309,7 @@ private IDictionary<string, string[]> BindPropertyResults(string alias, HbmRetur
 			{
 				newPropertyResults[entry.Key] = entry.Value;
 			}
-			return newPropertyResults.Count == 0 ? (IDictionary<string, string[]>)new CollectionHelper.EmptyMapClass<string, string[]>() : newPropertyResults;
+			return newPropertyResults.Count == 0 ? (IDictionary<string, string[]>)CollectionHelper.EmptyDictionary<string, string[]>() : newPropertyResults;
 		}
 
 		private static List<string> GetResultColumns(HbmReturnProperty returnPropertySchema)
diff --git a/src/NHibernate/Engine/JoinSequence.cs b/src/NHibernate/Engine/JoinSequence.cs
@@ -128,7 +128,7 @@ public JoinSequence AddJoin(IAssociationType associationType, string alias, Join
 
 		public JoinFragment ToJoinFragment()
 		{
-			return ToJoinFragment(new CollectionHelper.EmptyMapClass<string, IFilter>(), true);
+			return ToJoinFragment(CollectionHelper.EmptyDictionary<string, IFilter>(), true);
 		}
 
 		public JoinFragment ToJoinFragment(IDictionary<string, IFilter> enabledFilters, bool includeExtraJoins)
diff --git a/src/NHibernate/Hql/Ast/ANTLR/HqlSqlWalker.cs b/src/NHibernate/Hql/Ast/ANTLR/HqlSqlWalker.cs
@@ -393,7 +393,7 @@ private void PostProcessDML(IRestrictableStatement statement)
 			if (persister.DiscriminatorType != null)
 			{
 				new SyntheticAndFactory(this)
-					.AddDiscriminatorWhereFragment(statement, persister, new CollectionHelper.EmptyMapClass<string, IFilter>(), fromElement.TableAlias);
+					.AddDiscriminatorWhereFragment(statement, persister, CollectionHelper.EmptyDictionary<string, IFilter>(), fromElement.TableAlias);
 			}
 		}
 
diff --git a/src/NHibernate/Impl/SessionFactoryImpl.cs b/src/NHibernate/Impl/SessionFactoryImpl.cs
@@ -616,15 +616,15 @@ public string GetIdentifierPropertyName(string className)
 		public IType[] GetReturnTypes(String queryString)
 		{
 			return
-				queryPlanCache.GetHQLQueryPlan(queryString.ToQueryExpression(), false, new CollectionHelper.EmptyMapClass<string, IFilter>()).
+				queryPlanCache.GetHQLQueryPlan(queryString.ToQueryExpression(), false, CollectionHelper.EmptyDictionary<string, IFilter>()).
 					ReturnMetadata.ReturnTypes;
 		}
 
 		/// <summary> Get the return aliases of a query</summary>
 		public string[] GetReturnAliases(string queryString)
 		{
 			return
-				queryPlanCache.GetHQLQueryPlan(queryString.ToQueryExpression(), false, new CollectionHelper.EmptyMapClass<string, IFilter>()).
+				queryPlanCache.GetHQLQueryPlan(queryString.ToQueryExpression(), false, CollectionHelper.EmptyDictionary<string, IFilter>()).
 					ReturnMetadata.ReturnAliases;
 		}
 
@@ -1163,7 +1163,7 @@ private IDictionary<string, HibernateException> CheckNamedQueries()
 				{
 					log.Debug("Checking named query: {0}", queryName);
 					//TODO: BUG! this currently fails for named queries for non-POJO entities
-					queryPlanCache.GetHQLQueryPlan(qd.QueryString.ToQueryExpression(), false, new CollectionHelper.EmptyMapClass<string, IFilter>());
+					queryPlanCache.GetHQLQueryPlan(qd.QueryString.ToQueryExpression(), false, CollectionHelper.EmptyDictionary<string, IFilter>());
 				}
 				catch (QueryException e)
 				{
diff --git a/src/NHibernate/Impl/SqlQueryImpl.cs b/src/NHibernate/Impl/SqlQueryImpl.cs
@@ -93,7 +93,7 @@ protected internal override IDictionary<string, LockMode> LockModes
 			get
 			{
 				//we never need to apply locks to the SQL
-				return new CollectionHelper.EmptyMapClass<string, LockMode>();
+				return CollectionHelper.EmptyDictionary<string, LockMode>();
 			}
 		}
 
@@ -236,7 +236,7 @@ public ISQLQuery AddJoin(string alias, string path, LockMode lockMode)
 			string ownerAlias = path.Substring(0, loc);
 			string role = path.Substring(loc + 1);
 			queryReturns.Add(
-				new NativeSQLQueryJoinReturn(alias, ownerAlias, role, new CollectionHelper.EmptyMapClass<string, string[]>(), lockMode));
+				new NativeSQLQueryJoinReturn(alias, ownerAlias, role, CollectionHelper.EmptyDictionary<string, string[]>(), lockMode));
 			return this;
 		}
 
diff --git a/src/NHibernate/Impl/StatelessSessionImpl.cs b/src/NHibernate/Impl/StatelessSessionImpl.cs
@@ -288,7 +288,7 @@ public override IType GetFilterParameterType(string filterParameterName)
 
 		public override IDictionary<string, IFilter> EnabledFilters
 		{
-			get { return new CollectionHelper.EmptyMapClass<string, IFilter>(); }
+			get { return CollectionHelper.EmptyDictionary<string, IFilter>(); }
 		}
 
 		public override IQueryTranslator[] GetQueries(IQueryExpression query, bool scalar)
diff --git a/src/NHibernate/Loader/AbstractEntityJoinWalker.cs b/src/NHibernate/Loader/AbstractEntityJoinWalker.cs
@@ -33,7 +33,7 @@ protected virtual void InitAll(SqlString whereString, SqlString orderByString, L
 			IList<OuterJoinableAssociation> allAssociations = new List<OuterJoinableAssociation>(associations);
 			allAssociations.Add(
 				new OuterJoinableAssociation(persister.EntityType, null, null, alias, JoinType.LeftOuterJoin, null, Factory,
-											 new CollectionHelper.EmptyMapClass<string, IFilter>()));
+											 CollectionHelper.EmptyDictionary<string, IFilter>()));
 
 			InitPersisters(allAssociations, lockMode);
 			InitStatementString(whereString, orderByString, lockMode);
diff --git a/src/NHibernate/Loader/Collection/OneToManyJoinWalker.cs b/src/NHibernate/Loader/Collection/OneToManyJoinWalker.cs
@@ -38,7 +38,7 @@ public OneToManyJoinWalker(IQueryableCollection oneToManyPersister, int batchSiz
 			IList<OuterJoinableAssociation> allAssociations = new List<OuterJoinableAssociation>(associations);
 			allAssociations.Add(
 				new OuterJoinableAssociation(oneToManyPersister.CollectionType, null, null, alias, JoinType.LeftOuterJoin, null, Factory,
-				                             new CollectionHelper.EmptyMapClass<string, IFilter>()));
+				                             CollectionHelper.EmptyDictionary<string, IFilter>()));
 
 			InitPersisters(allAssociations, LockMode.None);
 			InitStatementString(elementPersister, alias, batchSize, subquery);
diff --git a/src/NHibernate/Loader/DefaultEntityAliases.cs b/src/NHibernate/Loader/DefaultEntityAliases.cs
@@ -19,7 +19,7 @@ public class DefaultEntityAliases : IEntityAliases
 		private readonly IDictionary<string, string[]> userProvidedAliases;
 
 		public DefaultEntityAliases(ILoadable persister, string suffix)
-			: this(new CollectionHelper.EmptyMapClass<string, string[]>(), persister, suffix) {}
+			: this(CollectionHelper.EmptyDictionary<string, string[]>(), persister, suffix) {}
 
 		/// <summary>
 		/// Calculate and cache select-clause suffixes.
@@ -147,4 +147,4 @@ private static void Intern(string[] strings)
 			}
 		}
 	}
-}
+}
diff --git a/src/NHibernate/Loader/Entity/CascadeEntityJoinWalker.cs b/src/NHibernate/Loader/Entity/CascadeEntityJoinWalker.cs
@@ -12,12 +12,12 @@ public class CascadeEntityJoinWalker : AbstractEntityJoinWalker
 
 		public CascadeEntityJoinWalker(IOuterJoinLoadable persister, CascadingAction action,
 		                               ISessionFactoryImplementor factory)
-			: base(persister, factory, new CollectionHelper.EmptyMapClass<string, IFilter>())
+			: base(persister, factory, CollectionHelper.EmptyDictionary<string, IFilter>())
 		{
 			cascadeAction = action;
 			SqlStringBuilder whereCondition = WhereString(Alias, persister.IdentifierColumnNames, 1)
 				//include the discriminator and class-level where, but not filters
-				.Add(persister.FilterFragment(Alias, new CollectionHelper.EmptyMapClass<string, IFilter>()));
+				.Add(persister.FilterFragment(Alias, CollectionHelper.EmptyDictionary<string, IFilter>()));
 
 			InitAll(whereCondition.ToSqlString(), SqlString.Empty, LockMode.Read);
 		}
diff --git a/src/NHibernate/Loader/Entity/CascadeEntityLoader.cs b/src/NHibernate/Loader/Entity/CascadeEntityLoader.cs
@@ -7,7 +7,7 @@ namespace NHibernate.Loader.Entity
 	public class CascadeEntityLoader : AbstractEntityLoader
 	{
 		public CascadeEntityLoader(IOuterJoinLoadable persister, CascadingAction action, ISessionFactoryImplementor factory)
-			: base(persister, persister.IdentifierType, factory, new CollectionHelper.EmptyMapClass<string, IFilter>())
+			: base(persister, persister.IdentifierType, factory, CollectionHelper.EmptyDictionary<string, IFilter>())
 		{
 			JoinWalker walker = new CascadeEntityJoinWalker(persister, action, factory);
 			InitFromWalker(walker);
diff --git a/src/NHibernate/Loader/Entity/EntityJoinWalker.cs b/src/NHibernate/Loader/Entity/EntityJoinWalker.cs
@@ -23,7 +23,7 @@ public EntityJoinWalker(IOuterJoinLoadable persister, string[] uniqueKey, int ba
 
 			SqlStringBuilder whereCondition = WhereString(Alias, uniqueKey, batchSize)
 				//include the discriminator and class-level where, but not filters
-				.Add(persister.FilterFragment(Alias, new CollectionHelper.EmptyMapClass<string, IFilter>()));
+				.Add(persister.FilterFragment(Alias, CollectionHelper.EmptyDictionary<string, IFilter>()));
 
 			InitAll(whereCondition.ToSqlString(), SqlString.Empty, lockMode);
 		}
diff --git a/src/NHibernate/Loader/GeneratedCollectionAliases.cs b/src/NHibernate/Loader/GeneratedCollectionAliases.cs
@@ -37,7 +37,7 @@ public GeneratedCollectionAliases(IDictionary<string, string[]> userProvidedAlia
 		}
 
 		public GeneratedCollectionAliases(ICollectionPersister persister, string str)
-			: this(new CollectionHelper.EmptyMapClass<string, string[]>(), persister, str) {}
+			: this(CollectionHelper.EmptyDictionary<string, string[]>(), persister, str) {}
 
 		private string[] GetUserProvidedCompositeElementAliases(string[] defaultAliases)
 		{
diff --git a/src/NHibernate/Persister/Collection/AbstractCollectionPersister.cs b/src/NHibernate/Persister/Collection/AbstractCollectionPersister.cs
@@ -559,7 +559,7 @@ public AbstractCollectionPersister(Mapping.Collection collection, ICacheConcurre
 		public void PostInstantiate()
 		{
 			initializer = queryLoaderName == null
-							? CreateCollectionInitializer(new CollectionHelper.EmptyMapClass<string, IFilter>())
+							? CreateCollectionInitializer(CollectionHelper.EmptyDictionary<string, IFilter>())
 							: new NamedQueryCollectionInitializer(queryLoaderName, this);
 		}
 
diff --git a/src/NHibernate/Persister/Entity/AbstractEntityPersister.cs b/src/NHibernate/Persister/Entity/AbstractEntityPersister.cs
@@ -2118,7 +2118,7 @@ protected void CreateUniqueKeyLoaders()
 					//don't need filters for the static loaders
 					uniqueKeyLoaders[propertyNames[i]] =
 						CreateUniqueKeyLoader(propertyTypes[i], GetPropertyColumnNames(i),
-																	new CollectionHelper.EmptyMapClass<string, IFilter>());
+																	CollectionHelper.EmptyDictionary<string, IFilter>());
 				}
 			}
 		}
@@ -2197,7 +2197,7 @@ protected IUniqueEntityLoader CreateEntityLoader(LockMode lockMode, IDictionary<
 
 		protected IUniqueEntityLoader CreateEntityLoader(LockMode lockMode)
 		{
-			return CreateEntityLoader(lockMode, new CollectionHelper.EmptyMapClass<string, IFilter>());
+			return CreateEntityLoader(lockMode, CollectionHelper.EmptyDictionary<string, IFilter>());
 		}
 
 		protected bool Check(int rows, object id, int tableNumber, IExpectation expectation, DbCommand statement)
diff --git a/src/NHibernate/Util/CollectionHelper.cs b/src/NHibernate/Util/CollectionHelper.cs
@@ -214,6 +214,12 @@ public IEnumerator GetEnumerator()
 
 		public static readonly IEnumerable EmptyEnumerable = new EmptyEnumerableClass();
 		public static readonly IDictionary EmptyMap = new EmptyMapClass();
+
+		public static IDictionary<TKey, TValue> EmptyDictionary<TKey, TValue>()
+		{
+			return EmptyDictionaryHolder<TKey, TValue>.Instance;
+		}
+
 		public static readonly ICollection EmptyCollection = EmptyMap;
 		// Since v5
 		[Obsolete("It has no more usages in NHibernate and will be removed in a future version.")]
@@ -457,6 +463,11 @@ public object Current
 			#endregion
 		}
 
+		private static class EmptyDictionaryHolder<TKey, TValue>
+		{
+			public static readonly EmptyMapClass<TKey, TValue> Instance = new EmptyMapClass<TKey, TValue>();
+		}
+
 		/// <summary>
 		/// A read-only dictionary that is always empty and permits lookup by <see langword="null" /> key.
 		/// </summary>

Original file line number	Diff line number	Diff line change
`@@ -9,7 +9,7 @@ namespace NHibernate.Cfg.MappingSchema`
`9`	`9`	`[Serializable]`
`10`	`10`	`public abstract class AbstractDecoratable : IDecoratable`
`11`	`11`	`{`
`12`		`- private static readonly IDictionary<string, MetaAttribute> EmptyMetaData = new CollectionHelper.EmptyMapClass<string, MetaAttribute>();`
	`12`	`+ private static readonly IDictionary<string, MetaAttribute> EmptyMetaData = CollectionHelper.EmptyDictionary<string, MetaAttribute>();`
`13`	`13`
`14`	`14`	`[NonSerialized]`
`15`	`15`	`[XmlIgnore]`
Original file line number	Diff line number	Diff line change
`@@ -309,7 +309,7 @@ private IDictionary<string, string[]> BindPropertyResults(string alias, HbmRetur`
`309`	`309`	`{`
`310`	`310`	`newPropertyResults[entry.Key] = entry.Value;`
`311`	`311`	`}`
`312`		`- return newPropertyResults.Count == 0 ? (IDictionary<string, string[]>)new CollectionHelper.EmptyMapClass<string, string[]>() : newPropertyResults;`
	`312`	`+ return newPropertyResults.Count == 0 ? (IDictionary<string, string[]>)CollectionHelper.EmptyDictionary<string, string[]>() : newPropertyResults;`
`313`	`313`	`}`
`314`	`314`
`315`	`315`	`private static List<string> GetResultColumns(HbmReturnProperty returnPropertySchema)`
Original file line number	Diff line number	Diff line change
`@@ -128,7 +128,7 @@ public JoinSequence AddJoin(IAssociationType associationType, string alias, Join`
`128`	`128`
`129`	`129`	`public JoinFragment ToJoinFragment()`
`130`	`130`	`{`
`131`		`- return ToJoinFragment(new CollectionHelper.EmptyMapClass<string, IFilter>(), true);`
	`131`	`+ return ToJoinFragment(CollectionHelper.EmptyDictionary<string, IFilter>(), true);`
`132`	`132`	`}`
`133`	`133`
`134`	`134`	`public JoinFragment ToJoinFragment(IDictionary<string, IFilter> enabledFilters, bool includeExtraJoins)`
Original file line number	Diff line number	Diff line change
`@@ -393,7 +393,7 @@ private void PostProcessDML(IRestrictableStatement statement)`
`393`	`393`	`if (persister.DiscriminatorType != null)`
`394`	`394`	`{`
`395`	`395`	`new SyntheticAndFactory(this)`
`396`		`- .AddDiscriminatorWhereFragment(statement, persister, new CollectionHelper.EmptyMapClass<string, IFilter>(), fromElement.TableAlias);`
	`396`	`+ .AddDiscriminatorWhereFragment(statement, persister, CollectionHelper.EmptyDictionary<string, IFilter>(), fromElement.TableAlias);`
`397`	`397`	`}`
`398`	`398`	`}`
`399`	`399`
Original file line number	Diff line number	Diff line change
`@@ -616,15 +616,15 @@ public string GetIdentifierPropertyName(string className)`
`616`	`616`	`public IType[] GetReturnTypes(String queryString)`
`617`	`617`	`{`
`618`	`618`	`return`
`619`		`- queryPlanCache.GetHQLQueryPlan(queryString.ToQueryExpression(), false, new CollectionHelper.EmptyMapClass<string, IFilter>()).`
	`619`	`+ queryPlanCache.GetHQLQueryPlan(queryString.ToQueryExpression(), false, CollectionHelper.EmptyDictionary<string, IFilter>()).`
`620`	`620`	`ReturnMetadata.ReturnTypes;`
`621`	`621`	`}`
`622`	`622`
`623`	`623`	`/// <summary> Get the return aliases of a query</summary>`
`624`	`624`	`public string[] GetReturnAliases(string queryString)`
`625`	`625`	`{`
`626`	`626`	`return`
`627`		`- queryPlanCache.GetHQLQueryPlan(queryString.ToQueryExpression(), false, new CollectionHelper.EmptyMapClass<string, IFilter>()).`
	`627`	`+ queryPlanCache.GetHQLQueryPlan(queryString.ToQueryExpression(), false, CollectionHelper.EmptyDictionary<string, IFilter>()).`
`628`	`628`	`ReturnMetadata.ReturnAliases;`
`629`	`629`	`}`
`630`	`630`
`@@ -1163,7 +1163,7 @@ private IDictionary<string, HibernateException> CheckNamedQueries()`
`1163`	`1163`	`{`
`1164`	`1164`	`log.Debug("Checking named query: {0}", queryName);`
`1165`	`1165`	`//TODO: BUG! this currently fails for named queries for non-POJO entities`
`1166`		`- queryPlanCache.GetHQLQueryPlan(qd.QueryString.ToQueryExpression(), false, new CollectionHelper.EmptyMapClass<string, IFilter>());`
	`1166`	`+ queryPlanCache.GetHQLQueryPlan(qd.QueryString.ToQueryExpression(), false, CollectionHelper.EmptyDictionary<string, IFilter>());`
`1167`	`1167`	`}`
`1168`	`1168`	`catch (QueryException e)`
`1169`	`1169`	`{`
Original file line number	Diff line number	Diff line change
`@@ -93,7 +93,7 @@ protected internal override IDictionary<string, LockMode> LockModes`
`93`	`93`	`get`
`94`	`94`	`{`
`95`	`95`	`//we never need to apply locks to the SQL`
`96`		`- return new CollectionHelper.EmptyMapClass<string, LockMode>();`
	`96`	`+ return CollectionHelper.EmptyDictionary<string, LockMode>();`
`97`	`97`	`}`
`98`	`98`	`}`
`99`	`99`
`@@ -236,7 +236,7 @@ public ISQLQuery AddJoin(string alias, string path, LockMode lockMode)`
`236`	`236`	`string ownerAlias = path.Substring(0, loc);`
`237`	`237`	`string role = path.Substring(loc + 1);`
`238`	`238`	`queryReturns.Add(`
`239`		`- new NativeSQLQueryJoinReturn(alias, ownerAlias, role, new CollectionHelper.EmptyMapClass<string, string[]>(), lockMode));`
	`239`	`+ new NativeSQLQueryJoinReturn(alias, ownerAlias, role, CollectionHelper.EmptyDictionary<string, string[]>(), lockMode));`
`240`	`240`	`return this;`
`241`	`241`	`}`
`242`	`242`
Original file line number	Diff line number	Diff line change
`@@ -288,7 +288,7 @@ public override IType GetFilterParameterType(string filterParameterName)`
`288`	`288`
`289`	`289`	`public override IDictionary<string, IFilter> EnabledFilters`
`290`	`290`	`{`
`291`		`- get { return new CollectionHelper.EmptyMapClass<string, IFilter>(); }`
	`291`	`+ get { return CollectionHelper.EmptyDictionary<string, IFilter>(); }`
`292`	`292`	`}`
`293`	`293`
`294`	`294`	`public override IQueryTranslator[] GetQueries(IQueryExpression query, bool scalar)`