Luke changes. Reason for usage of Decorator pattern in Part 3 was unc…

DesignPatternsSolution/Execise.Tests/UnitTests.cs

@@ -6,24 +6,39 @@ namespace Execise.Tests
     [TestClass]
     public class UnitTests
     {
-        //test the two calls to library instance return same instance
         [TestMethod]
         public void LibraryShouldBeSingleton()
         {
-            //check that when you create a Library instance second time, 
-            //you get exactly the same instance as for a very first time
+            var library1 = Library.GetInstance();
+            var library2 = Library.GetInstance();
+
+            Assert.AreEqual(library1, library2);
         }
 
         //test that an book was registered successfully by checking the returned Id value is not -1
         [TestMethod]
         public void BookShouldRegister()
         {
+            var book = new Book("The Author", "The Book", 2001, 25);
+
+            var library = Library.GetInstance();
+
+            var registrationResult = library.Register(book);
+
+            Assert.AreNotEqual(-1, registrationResult);
         }
 
         //test that an customer was registered successfully by checking the returned Id value is not -1
         [TestMethod]
         public void CustomerShouldRegister()
         {
+            var customer = new Customer("Fred", "123 Place St.");
+
+            var library = Library.GetInstance();
+
+            var registrationResult = library.Register(customer);
+
+            Assert.AreNotEqual(-1, registrationResult);
         }
 
         //test that a book can be borrowed
@@ -33,6 +48,13 @@ public void CanBorrowBook()
             //create a borrowable book with available amount more than one. 
             //Run BorrowOne method of the BookBorrowable instance. Check that total amount was reduced by one.
 
+            var book = new Book("Mr. Cat", "Supertown", 2009, 7);
+
+            var borrowableBook = new BorrowableBook(book);
+
+            borrowableBook.BorrowOne();
+
+            Assert.AreEqual(6, borrowableBook.AvailableAmount);
         }       
     }
 }

DesignPatternsSolution/Exercise/BookBorrowable.cs

@@ -1,7 +1,28 @@
 namespace Exercise
 {
-    public class BookBorrowable 
+    /*
+     * Instructions unclear. Did this.
+    */
+    public abstract class BookDecorator : Book
     {
-
+        private Book _book;
+
+        protected BookDecorator(Book book)
+            : base(book.Author, book.NameOrTitle, book.YearCreated, book.AvailableAmount)
+        {
+            _book = book;
+        }
+    }
+
+    public class BorrowableBook : BookDecorator
+    {
+        public BorrowableBook(Book book)
+            : base(book)
+        { }
+
+        public void BorrowOne()
+        {
+            AvailableAmount--;
+        }
     }
 }

DesignPatternsSolution/Exercise/Item.cs

@@ -1,18 +1,31 @@
-namespace Exercise
+using System;
+
+namespace Exercise
 {
-    public abstract class Item : LibObject
+    public abstract class Item : LibObject, IRegistrable
     {
         public Item(int amount, int year)
         {
             AvailableAmount = amount;
             ObjType = ObjectType.Item;
             YearCreated = year;
         }
+
+        public RegisteredObject GetRegistrationInfo()
+        {
+            return new RegisteredObject
+            {
+                Id = ObjectId,
+                AvailableAmount = AvailableAmount,
+                Info = String.Format("{0} ({1})", NameOrTitle ?? ObjType.ToString(), YearCreated)
+            };
+        }
     }
 
     public class Book : Item
     {
-        public Book(string author, string title, int year, int amount) : base(amount, year)
+        public Book(string author, string title, int year, int amount)
+            : base(amount, year)
         {
             NameOrTitle = title;
             Author = author;

DesignPatternsSolution/Exercise/Library.cs

@@ -3,16 +3,19 @@
     public class Library
     {
         //implement Singleton to make sure only one library will exist
+        private static Library _library;
 
-
+        private Library() {}
 
         //Implement Register method by utilizing RegistrationRepository (complete missing parts)
-        public int Register()
+        public int Register(IRegistrable registrableItem)
         {
-            // return RegistrationRepository.Register();
+            return RegistrationRepository.Register(registrableItem);
+        }
 
-            //dummy, just to compile
-            return 0;
+        public static Library GetInstance()
+        {
+            return _library ?? (_library = new Library());
         }
     }
 }

DesignPatternsSolution/Exercise/Person.cs

@@ -2,7 +2,7 @@
 
 namespace Exercise
 {
-    public class Customer : LibObject
+    public class Customer : LibObject, IRegistrable
     {
         public string Address { get; set; }
         public DateTime RegisteredAt { get; set; }
@@ -19,5 +19,15 @@ public void SetId(int id)
         {
             ObjectId = id;
         }
+
+        public RegisteredObject GetRegistrationInfo()
+        {
+            return new RegisteredObject
+            {
+                Id = ObjectId,
+                AvailableAmount = AvailableAmount,
+                Info = String.Format("{0} of {1} ({2})", NameOrTitle, Address, RegisteredAt)
+            };
+        }
     }
 }

DesignPatternsSolution/Exercise/Registration.cs

@@ -3,7 +3,7 @@
 using System.Linq;
 namespace Exercise
 {
-    public interface IRegistarable
+    public interface IRegistrable
     {
         RegisteredObject GetRegistrationInfo();
     }
@@ -16,7 +16,7 @@ public static class RegistrationRepository
         private static int _nextId = 1;
 
         //With BRIDGE pattern, implement Register method so it will accept both a Person and an Item
-        public static int Register(IRegistarable registarable)
+        public static int Register(IRegistrable registarable)
         {
             //get info from an lib object
             var info = registarable.GetRegistrationInfo();
@@ -37,7 +37,7 @@ public static int Register(IRegistarable registarable)
 
         public static int DeleteAllRegisteredItems()
         {
-            var size = _registeredList.Count();
+            var size = _registeredList.Count;
             _registeredList.RemoveRange(0, size);
             _nextId = 1;
 
@@ -53,7 +53,7 @@ public class RegisteredObject
 
         public override string ToString()
         {
-            return Info + " " + "Available: " + AvailableAmount;
+            return string.Format("{0} Available: {1}", Info, AvailableAmount);
         }
     }
 }