Working on a pipeline pattern implementation

Author: Craig W. Selbert

ConsoleApplication/Program.cs

@@ -4,44 +4,58 @@
 using UMV.Reference.ClassLibrary.Ninject;
 using UMV.Reference.Patterns;
 using UMV.Reference.Patterns.Aspects;
+using UMV.Reference.Patterns.Base.Interfaces;
 using UMV.Reference.Patterns.Models;
-using UMV.Reference.Patterns.Operations;
+using UMV.Reference.Patterns.Ninject;
+using UMV.Reference.Patterns.Operations.Interfaces;
 
 namespace UMV.Reference.ConsoleApplication
 {
     class Program
     {
         static void Main(string[] args)
+        {
+            PipelineExample();
+
+            Console.ReadLine();
+        }
+
+        private static void TestChangeTracking()
         {
             var member = new Member();
 
             member.FirstName = "Craig";
 
-            member.Initialize();
+            member.InitializeChangeState();
 
             member.FirstName = "CRAIG";
 
-            var changes = member.GetChanges();
-
-            Console.ReadLine();
+            var changes = member.GetChangeState();
         }
 
         private static void PipelineExample()
         {
+            var kernel = new StandardKernel(new PatternsModule());
             var context = new Member();
 
-            IOperation<Member> m = null;
+            var trackChanges = kernel.Get<IOperation<IChangeTrackable>>("TrackChanges");
+            var addAuditInformation = kernel.Get<IOperation<IAuditible>>("AddAuditInformation");
+            var updateMemberNameToCraigOperation = kernel.Get<IOperation<Member>>("UpdateMemberNameToCraigOperation");
+            var initializeChangeTracking = kernel.Get<IOperation<IChangeTrackable>>("InitializeChangeTracking");
 
             // Build up your pipeline
-            var pipeline = new Pipeline<Member>()
-                .Register(m)
-                .Register(new AddMemberNameOperation());
+            var pipeline = new Pipeline<IChangeTrackable>()
+                .Register(initializeChangeTracking)
+                .Register(addAuditInformation)
+                .Register(updateMemberNameToCraigOperation)
+                .Register(trackChanges)
+                ;
 
             // Add aspects around the pipline 
-            var exceptionLogginAspect = new ExceptionLoggingAspect<Member>(pipeline.Execute);
+            var exceptionLogginAspect = new ExceptionLoggingAspect<IChangeTrackable>(pipeline.Execute);
 
             // Execute 
-            context = exceptionLogginAspect.Execute(context);
+            context = exceptionLogginAspect.Execute(context) as Member;
 
             Console.WriteLine(context.FirstName);
         }

Patterns/Base/ChangeTrackable.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using UMV.Reference.Patterns.Base.Interfaces;
+using UMV.Reference.Patterns.Base.Models;
+
+namespace UMV.Reference.Patterns.Base
+{
+    public abstract class ChangeTrackable : Auditible, IChangeTrackable
+    {
+        private readonly List<PropertyInfo> _properties;
+        private readonly List<PropertyInfo> _propertiesToIgnore;
+        private readonly Dictionary<string, object> _originalValues = new Dictionary<string, object>();
+
+        protected ChangeTrackable()
+        {
+            _propertiesToIgnore = typeof(Auditible).GetProperties().ToList();
+            _properties = GetType().GetProperties().Where(x => !_propertiesToIgnore.Contains(x)).ToList();
+        }
+
+        public void InitializeChangeState()
+        {
+            // Save the current value of the properties to our dictionary.
+            foreach (var property in _properties)
+                _originalValues.Add(property.Name, property.GetValue(this));
+        }
+
+        public ChangeState GetChangeState()
+        {
+            // Filter properties by only getting what has changed
+            var changedProperties = _properties.Where(p => !Equals(p.GetValue(this, null), _originalValues[p.Name])).ToArray();
+
+            return new ChangeState
+            {
+                CreateDate = CreateDate,
+                UpdateDate = UpdateDate,
+                UpdateUser = UpdateUser,
+                CreateUser = CreateUser,
+                ChangedProperties = changedProperties.Select(x => new ChangedProperty
+                {
+                    Name = x.Name,
+                    CurrentValue = x.GetValue(this),
+                    OriginalValue = _originalValues[x.Name]
+                })
+            };
+        }
+    }
+}

Patterns/Base/ChangeTrackingBase.cs

@@ -0,0 +1,9 @@
+namespace UMV.Reference.Patterns.Base.Enums
+{
+    public enum ObjectState
+    {
+        New,
+        Changed,
+        NoChange
+    }
+}

Patterns/Base/Enums/ObjectState.cs

@@ -1,9 +1,12 @@
 using System;
+using UMV.Reference.Patterns.Base.Enums;
 
 namespace UMV.Reference.Patterns.Base.Interfaces
 {
-    public interface IAuditible
+    public interface IAuditible : IIdentifiable
     {
+        ObjectState ObjectState { get; set; }
+
         string CreateUser { get; set; }
 
         DateTime CreateDate { get; set; }

Patterns/Base/Interfaces/IAuditible.cs

@@ -0,0 +1,12 @@
+using UMV.Reference.Patterns.Base.Models;
+
+namespace UMV.Reference.Patterns.Base.Interfaces
+{
+    public interface IChangeTrackable : IAuditible
+    {
+        ChangeState GetChangeState();
+
+        void InitializeChangeState();
+
+    }
+}

Patterns/Base/Interfaces/IChangeTrackable.cs

@@ -0,0 +1,7 @@
+namespace UMV.Reference.Patterns.Base.Interfaces
+{
+    public interface IIdentifiable
+    {
+        int Id { get; set; }
+    }
+}

Patterns/Base/Interfaces/IIdentifiable.cs

@@ -1,9 +1,10 @@
 using System;
+using UMV.Reference.Patterns.Base.Enums;
 using UMV.Reference.Patterns.Base.Interfaces;
 
-namespace UMV.Reference.Patterns.Base
+namespace UMV.Reference.Patterns.Base.Models
 {
-    public abstract class Auditible : IAuditible
+    public abstract class Auditible : Identifiable, IAuditible
     {
         public string CreateUser { get; set; }
 
@@ -12,5 +13,7 @@ public abstract class Auditible : IAuditible
         public string UpdateUser { get; set; }
 
         public DateTime UpdateDate { get; set; }
+
+        public ObjectState ObjectState { get; set; }
     }
 }

Patterns/Base/Auditible.cs renamed to Patterns/Base/Models/Auditible.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Collections.Generic;
+using UMV.Reference.Patterns.Base.Enums;
+using UMV.Reference.Patterns.Base.Interfaces;
+
+namespace UMV.Reference.Patterns.Base.Models
+{
+    public class ChangeState : IAuditible
+    {
+        public int Id { get; set; }
+
+        public string CreateUser { get; set; }
+
+        public DateTime CreateDate { get; set; }
+
+        public string UpdateUser { get; set; }
+
+        public DateTime UpdateDate { get; set; }
+
+        public ObjectState ObjectState { get; set; }
+
+        public IEnumerable<ChangedProperty> ChangedProperties { get; set; }
+
+    }
+}

Patterns/Base/Models/ChangeState.cs

@@ -0,0 +1,11 @@
+namespace UMV.Reference.Patterns.Base.Models
+{
+    public class ChangedProperty
+    {
+        public string Name { get; set; }
+
+        public object OriginalValue { get; set; }
+
+        public object CurrentValue { get; set; }
+    }
+}