Change mapping to use contructor for default type

Author: Tasteful

src/Nest/Domain/Mapping/Types/BooleanMapping.cs

@@ -8,9 +8,8 @@ namespace Nest
 	[JsonObject(MemberSerialization.OptIn)]
 	public class BooleanMapping : MultiFieldMapping, IElasticType, IElasticCoreType
 	{
-		public BooleanMapping()
+		public BooleanMapping():base("boolean")
 		{
-			Type = "boolean";
 		}
 
 		/// <summary>

src/Nest/Domain/Mapping/Types/DateMapping.cs

@@ -8,9 +8,8 @@ namespace Nest
 	[JsonObject(MemberSerialization.OptIn)]
 	public class DateMapping : MultiFieldMapping, IElasticType, IElasticCoreType
 	{
-		public DateMapping()
+		public DateMapping():base("date")
 		{
-			Type = "date";
 		}
 
 		/// <summary>

src/Nest/Domain/Mapping/Types/GenericMapping.cs

@@ -12,9 +12,8 @@ namespace Nest
 	[JsonObject(MemberSerialization.OptIn)]
 	public class GenericMapping : MultiFieldMapping, IElasticType, IElasticCoreType
 	{
-		public GenericMapping()
+		public GenericMapping():base(null)
 		{
-			Type = string.Empty;
 		}
 
 		/// <summary>

src/Nest/Domain/Mapping/Types/MultiFieldMapping.cs

@@ -8,14 +8,27 @@ namespace Nest
 	[JsonObject(MemberSerialization.OptIn)]
 	public class MultiFieldMapping : IElasticType
 	{
+		private readonly TypeNameMarker _defaultType;
+
+		public MultiFieldMapping()
+			: this("multi_field")
+		{
+			this.Fields = new Dictionary<PropertyNameMarker, IElasticCoreType>();
+		}
+
+		protected MultiFieldMapping(TypeNameMarker defaultType)
+		{
+			_defaultType = defaultType;
+		}
+
 		public PropertyNameMarker Name { get; set; }
 
 		private TypeNameMarker _typeOverride;
 
 		[JsonProperty("type")]
 		public virtual TypeNameMarker Type
 		{
-			get { return _typeOverride ?? new TypeNameMarker { Name = "multi_field" }; }
+			get { return _typeOverride ?? _defaultType; }
 			set { _typeOverride = value; }
 		}
 
@@ -30,12 +43,6 @@ public virtual TypeNameMarker Type
 
 		[JsonProperty("fields", DefaultValueHandling = DefaultValueHandling.Ignore), JsonConverter(typeof(ElasticCoreTypeConverter))]
 		public IDictionary<PropertyNameMarker, IElasticCoreType> Fields { get; set; }
-
-
-		public MultiFieldMapping()
-		{
-			this.Fields = new Dictionary<PropertyNameMarker, IElasticCoreType>();
-		}
 	}
 
     public class MultiFieldMappingPath

src/Nest/Domain/Mapping/Types/NumberMapping.cs

@@ -1,47 +1,47 @@
 using System.Collections.Generic;
-using Newtonsoft.Json;
-using System;
+using Newtonsoft.Json;
+using System;
 using Newtonsoft.Json.Converters;
 
-namespace Nest
-{
+namespace Nest
+{
 	[JsonObject(MemberSerialization.OptIn)]
-	public class NumberMapping : MultiFieldMapping, IElasticType, IElasticCoreType
+	public class NumberMapping : MultiFieldMapping, IElasticType, IElasticCoreType
 	{
 		public NumberMapping()
+			: base("double")
 		{
-			Type = "double";
 		}
-
-		/// <summary>
-		/// The name of the field that will be stored in the index. Defaults to the property/field name.
-		/// </summary>
-		[JsonProperty("index_name")]
-		public string IndexName { get; set; }
-
-		[JsonProperty("store")]
-		public bool? Store { get; set; }
-
-		[JsonProperty("index"), JsonConverter(typeof(StringEnumConverter))]
-		public NonStringIndexOption? Index { get; set; }
-
-		[JsonProperty("precision_step")]
-		public int? PrecisionStep { get; set; }
-
-		[JsonProperty("boost")]
-		public double? Boost { get; set; }
-
-		[JsonProperty("null_value")]
-		public double? NullValue { get; set; }
-
+
+		/// <summary>
+		/// The name of the field that will be stored in the index. Defaults to the property/field name.
+		/// </summary>
+		[JsonProperty("index_name")]
+		public string IndexName { get; set; }
+
+		[JsonProperty("store")]
+		public bool? Store { get; set; }
+
+		[JsonProperty("index"), JsonConverter(typeof(StringEnumConverter))]
+		public NonStringIndexOption? Index { get; set; }
+
+		[JsonProperty("precision_step")]
+		public int? PrecisionStep { get; set; }
+
+		[JsonProperty("boost")]
+		public double? Boost { get; set; }
+
+		[JsonProperty("null_value")]
+		public double? NullValue { get; set; }
+
 		[JsonProperty("doc_values")]
-		public bool? DocValues { get; set; }
-
+		public bool? DocValues { get; set; }
+
 		[JsonProperty("ignore_malformed")]
 		public bool? IgnoreMalformed { get; set; }
 
-		[JsonProperty("coerce")]
-		public bool? Coerce { get; set; }
-
-	}
+		[JsonProperty("coerce")]
+		public bool? Coerce { get; set; }
+
+	}
 }

src/Nest/Domain/Mapping/Types/StringMapping.cs

@@ -8,9 +8,8 @@ namespace Nest
 	[JsonObject(MemberSerialization.OptIn)]
 	public class StringMapping : MultiFieldMapping, IElasticType, IElasticCoreType
 	{
-		public StringMapping()
+		public StringMapping():base("string")
 		{
-			Type = "string";
 		}
 
 		/// <summary>