/// <summary>
/// By introducing the MemberDecoratorBase, that 'wraps' a Member-subtype, we can easily add behaviour to a member implementation on demand. This alliviates class explosion, and further gives us the ability to decorate the same class multiple times.
/// </summary>
public static void Main()
{
IMember clint = Member.CreateMember("Clint Eastwood", 300);
Debug.WriteLine(clint.GetMemberStatus());
// Using the decorator pattern, we can now 'wrap' the original object in new clothes.
// This is why the pattern is sometimes also called the 'wrapper pattern'.
WithSpecialOfferDecorator specialDealForClint = new WithSpecialOfferDecorator(clint, 100);
Debug.WriteLine(specialDealForClint.GetMemberStatus());
WithAnniversaryDecorator anniversaryDealForClint = new WithAnniversaryDecorator(clint);
Debug.WriteLine(anniversaryDealForClint.GetMemberStatus());
// we can apply different decorators - wrappers - to the same member.
WithAnniversaryDecorator anniversaryDealForSpecialOfferClint = new WithAnniversaryDecorator(specialDealForClint);
Debug.WriteLine(anniversaryDealForSpecialOfferClint.GetMemberStatus());
// We can easily use the same wrapper twice - twice the special deal!
// This wasn't so easy before we applied the pattern.
Member multipleDealsArnold = Member.CreateMember("Arnold Schwarzenegger", 300);
WithSpecialOfferDecorator firstSpecialDealForArnold = new WithSpecialOfferDecorator(multipleDealsArnold, 500);
WithSpecialOfferDecorator secondSpecialDealForArnold = new WithSpecialOfferDecorator(firstSpecialDealForArnold, 500);
WithSpecialOfferDecorator thirdSpecialDealForArnold = new WithSpecialOfferDecorator(secondSpecialDealForArnold, 500);
Debug.WriteLine(thirdSpecialDealForArnold.GetMemberStatus());
}
public void DecoratorTests_CanDecorate()
{
// arrange
Member multipleDealsArnold = Member.CreateMember("Arnold Schwarzenegger", 300);
// act
WithSpecialOfferDecorator firstSpecialDealForArnold = new WithSpecialOfferDecorator(multipleDealsArnold, 500);
WithSpecialOfferDecorator secondSpecialDealForArnold = new WithSpecialOfferDecorator(firstSpecialDealForArnold, 500);
WithSpecialOfferDecorator thirdSpecialDealForArnold = new WithSpecialOfferDecorator(secondSpecialDealForArnold, 500);
var points = thirdSpecialDealForArnold.Points;
// assert
Assert.AreEqual(points, 1800);
}
