Refactored ReadPreference to not using Optional<T> and move Optional<T> to MongoDB.Driver namespace.

Author: rstam

src/MongoDB.Driver.Core.Tests/ReadPreferenceTests.cs

@@ -26,8 +26,6 @@ namespace MongoDB.Driver
     [TestFixture]
     public class ReadPreferenceTests
     {
-        private static readonly ReadPreference __defaults = new ReadPreference();
-
         [Test]
         public void constructor_should_throw_when_mode_is_primary_and_tagSets_is_not_empty()
         {
@@ -39,11 +37,12 @@ public void constructor_should_throw_when_mode_is_primary_and_tagSets_is_not_emp
         }
 
         [Test]
-        public void constructor_should_throw_when_tagSets_is_null()
+        public void constructor_should_initialize_instance_when_tagSets_is_null()
         {
-            Action action = () => new ReadPreference(ReadPreferenceMode.Primary, null);
+            var result = new ReadPreference(ReadPreferenceMode.Secondary, null);
 
-            action.ShouldThrow<ArgumentNullException>().And.ParamName.Should().Be("tagSets");
+            result.ReadPreferenceMode.Should().Be(ReadPreferenceMode.Secondary);
+            result.TagSets.Should().BeEmpty();
         }
 
         [Test]
@@ -54,22 +53,13 @@ public void constructor_with_mode_should_initialize_instance()
             var result = new ReadPreference(mode: mode);
 
             result.ReadPreferenceMode.Should().Be(mode);
-            result.TagSets.Should().Equal(__defaults.TagSets);
-        }
-
-        [Test]
-        public void constructor_with_no_arguments_should_initialize_instance()
-        {
-            var result = new ReadPreference();
-
-            result.ReadPreferenceMode.Should().Be(ReadPreferenceMode.Primary);
-            result.TagSets.Count.Should().Be(0);
+            result.TagSets.Should().BeEmpty();
         }
 
         [Test]
         public void constructor_with_tagSets_should_initialize_instance()
         {
-            var mode = ReadPreferenceMode.Secondary; // can't use tagSets with default mode Primary
+            var mode = ReadPreferenceMode.Secondary; // can't use tagSets with mode Primary
             var tagSets = new[] { new TagSet(new[] { new Tag("name", "value") }) };
 
             var result = new ReadPreference(mode: mode, tagSets: tagSets);

src/MongoDB.Driver.Core.Tests/Specifications/server-selection/ServerSelectionTestRunner.cs

@@ -99,7 +99,7 @@ private ReadPreference BuildReadPreference(BsonDocument readPreferenceDescriptio
                     throw new NotSupportedException("Unknown read preference mode: " + readPreferenceDescription["mode"]);
             }
 
-            return readPreference.With(tagSets: Optional.Enumerable(tagSets));
+            return readPreference.With(tagSets: tagSets);
         }
 
         private ClusterDescription BuildClusterDescription(BsonDocument topologyDescription)

src/MongoDB.Driver.Core/MongoDB.Driver.Core.csproj

@@ -123,7 +123,7 @@
     <Compile Include="Core\Events\ConnectionBeforeClosingEvent.cs" />
     <Compile Include="Core\Events\ConnectionFailedEvent.cs" />
     <Compile Include="Core\Misc\ExceptionMapper.cs" />
-    <Compile Include="Core\Misc\Optional.cs" />
+    <Compile Include="Optional.cs" />
     <Compile Include="Core\Misc\ReferenceCounted.cs" />
     <Compile Include="Core\Bindings\WritableServerBinding.cs" />
     <Compile Include="Core\Clusters\ServerSelectors\WritableServerSelector.cs" />

src/MongoDB.Driver.Core/Core/Misc/Optional.cs renamed to src/MongoDB.Driver.Core/Optional.cs

@@ -19,7 +19,7 @@
 using System.Text;
 using System.Threading.Tasks;
 
-namespace MongoDB.Driver.Core.Misc
+namespace MongoDB.Driver
 {
     /// <summary>
     /// Represents helper methods for use with the <see cref="Optional{T}"/> struct.

src/MongoDB.Driver.Core/ReadPreference.cs

@@ -102,11 +102,11 @@ public static ReadPreference SecondaryPreferred
         /// <param name="mode">The read preference mode.</param>
         /// <param name="tagSets">The tag sets.</param>
         public ReadPreference(
-            Optional<ReadPreferenceMode> mode = default(Optional<ReadPreferenceMode>), 
-            Optional<IEnumerable<TagSet>> tagSets = default(Optional<IEnumerable<TagSet>>))
+            ReadPreferenceMode mode, 
+            IEnumerable<TagSet> tagSets = null)
         {
-            _mode = mode.WithDefault(ReadPreferenceMode.Primary);
-            _tagSets = Ensure.IsNotNull(tagSets.WithDefault(Enumerable.Empty<TagSet>()), "tagSets").ToList();
+            _mode = mode;
+            _tagSets = (tagSets ?? Enumerable.Empty<TagSet>()).ToList();
 
             if (_mode == ReadPreferenceMode.Primary && _tagSets.Count() > 0)
             {
@@ -176,15 +176,20 @@ public override string ToString()
         /// Returns a new instance of ReadPreference with some values changed.
         /// </summary>
         /// <param name="mode">The read preference mode.</param>
+        /// <returns>A new instance of ReadPreference.</returns>
+        public ReadPreference With(ReadPreferenceMode mode)
+        {
+            return new ReadPreference(mode, _tagSets);
+        }
+
+        /// <summary>
+        /// Returns a new instance of ReadPreference with some values changed.
+        /// </summary>
         /// <param name="tagSets">The tag sets.</param>
         /// <returns>A new instance of ReadPreference.</returns>
-        public ReadPreference With(
-            Optional<ReadPreferenceMode> mode = default(Optional<ReadPreferenceMode>), 
-            Optional<IEnumerable<TagSet>> tagSets = default(Optional<IEnumerable<TagSet>>))
+        public ReadPreference With(IEnumerable<TagSet> tagSets)
         {
-            return new ReadPreference(
-                mode.WithDefault(_mode),
-                Optional.Enumerable(tagSets.WithDefault(_tagSets)));
+            return new ReadPreference(_mode, tagSets);
         }
     }
 }

src/MongoDB.Driver.Core/WriteConcern.cs

@@ -15,9 +15,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using MongoDB.Bson;
 using MongoDB.Driver.Core.Misc;
 using MongoDB.Shared;
@@ -125,7 +122,7 @@ public WriteConcern(
             Optional<TimeSpan?> wTimeout = default(Optional<TimeSpan?>),
             Optional<bool?> fsync = default(Optional<bool?>),
             Optional<bool?> journal = default(Optional<bool?>))
-            : this((WValue)Ensure.IsGreaterThanOrEqualToZero(w, "w"), wTimeout, fsync, journal)
+            : this(new WCount(Ensure.IsGreaterThanOrEqualToZero(w, "w")), wTimeout, fsync, journal)
         {
         }
 
@@ -141,7 +138,7 @@ public WriteConcern(
             Optional<TimeSpan?> wTimeout = default(Optional<TimeSpan?>),
             Optional<bool?> fsync = default(Optional<bool?>),
             Optional<bool?> journal = default(Optional<bool?>))
-            : this((WValue)Ensure.IsNotNullOrEmpty(mode, "mode"), wTimeout, fsync, journal)
+            : this(new WMode(Ensure.IsNotNullOrEmpty(mode, "mode")), wTimeout, fsync, journal)
         {
         }
 

src/MongoDB.Driver/MongoUrlBuilder.cs

@@ -561,7 +561,7 @@ public void Parse(string url)
                 {
                     throw new MongoConfigurationException("ReadPreferenceMode is required when using tag sets.");
                 }
-                _readPreference = _readPreference.With(tagSets: Optional.Enumerable(connectionString.ReadPreferenceTags));
+                _readPreference = _readPreference.With(tagSets: connectionString.ReadPreferenceTags);
             }
 
             _replicaSetName = connectionString.ReplicaSet;