Adding a factory for creating filters in a non-generic way (issue #25)

ExpressionBuilder.Test/Unit/FilterTest.cs

@@ -2,6 +2,7 @@
 using ExpressionBuilder.Generics;
 using ExpressionBuilder.Operations;
 using ExpressionBuilder.Test.Models;
+using FluentAssertions;
 using NUnit.Framework;
 using System;
 using System.Linq;
@@ -77,5 +78,12 @@ public void ShouldNotStartGroupIfPreviousOneIsEmpty()
             filter.StartGroup();
             Assert.That(filter.Statements.Count(), Is.EqualTo(1));
         }
+
+        [TestCase(TestName = "Should create a filter by passing the type as an argument")]
+        public void ShouldCreateAFilterByPassingTheTypeAsAnArgument()
+        {
+            var filter = FilterFactory.Create(typeof(Person));
+            filter.Should().BeOfType(typeof(Filter<Person>));
+        }
     }
 }

ExpressionBuilder/ExpressionBuilder.csproj

@@ -61,8 +61,9 @@
     <Compile Include="Exceptions\PropertyValueTypeMismatchException.cs" />
     <Compile Include="Exceptions\WrongNumberOfValuesException.cs" />
     <Compile Include="Exceptions\UnsupportedOperationException.cs" />
-    <Compile Include="Generics\FilterStatement.cs" />
+    <Compile Include="FilterFactory.cs" />
     <Compile Include="Generics\Filter.cs" />
+    <Compile Include="Generics\FilterStatement.cs" />
     <Compile Include="Generics\FilterStatementConnection.cs" />
     <Compile Include="Helpers\OperationEqualityComparer.cs" />
     <Compile Include="Helpers\OperationHelper.cs" />

ExpressionBuilder/FilterFactory.cs

@@ -0,0 +1,24 @@
+using ExpressionBuilder.Generics;
+using ExpressionBuilder.Interfaces;
+using System;
+
+namespace ExpressionBuilder
+{
+    /// <summary>
+    /// </summary>
+    public static class FilterFactory
+    {
+        /// <summary>
+        /// Creates a Filter&lt;TClass&gt; by passing the 'TClass' as a parameter.
+        /// </summary>
+        /// <param name="type"></param>
+        /// <typeparam name="TClass"></typeparam>
+        /// <returns></returns>
+        public static IFilter Create(Type type)
+        {
+            Type[] typeArgs = { type };
+            var filterType = typeof(Filter<>).MakeGenericType(typeArgs);
+            return (IFilter)Activator.CreateInstance(filterType);
+        }
+    }
+}