static void Main(string[] args)
{
IShape circle = new Circle();
IShape rectangle = new Rectangle();
Console.WriteLine("Exibindo Circulo");
circle.Draw();
Console.WriteLine(string.Empty);
Console.WriteLine("Exibindo Retangulo");
rectangle.Draw();
Console.WriteLine(string.Empty);
Console.WriteLine(string.Empty);
Console.WriteLine("Adicionando funcionalidade de alteração de cores aos shapes");
ShapeDecorator decoratedCircle = new RedShapeDecorator(circle);
ShapeDecorator decoratedRectangle = new RedShapeDecorator(rectangle);
Console.WriteLine("Exibindo Circulo");
decoratedCircle.Draw();
Console.WriteLine(string.Empty);
Console.WriteLine("Exibindo Retangulo");
decoratedRectangle.Draw();
}
public static void Demo()
{
Factory.IShape c = new Factory.Circle();
Factory.IShape rc = new RedShapeDecorator(new Factory.Circle());
c.Draw();
rc.Draw();
Console.ReadLine();
}
static void Main(string[] args)
{
Shape circle = new Circle();
Shape redCircle = new RedShapeDecorator(new Circle());
Shape redRectangle = new RedShapeDecorator(new Rectangle());
Console.WriteLine("Circle with norm border");
circle.draw();
Console.WriteLine("\nCircle with red border");
redCircle.draw();
Console.WriteLine("\nRectangle with red border");
redRectangle.draw();
Console.Read();
}
static void Main(string[] args)
{
// 待维护
IShape circle = new Circle();
IShape redCircle = new RedShapeDecorator(new Circle());
RedShapeDecorator redRectangle = new RedShapeDecorator(new Rectangle());
Console.WriteLine("Circle with normal border");
circle.Draw();
Console.WriteLine("\nCircle of red border");
redCircle.Draw();
Console.WriteLine("\nRectangle of red border");
redRectangle.Draw();
Console.ReadKey();
}
public MainWindow()
{
InitializeComponent();
this.Height = 950;
this.Width = 925;
this.GuiUC.DefineText = "Decorator pattern allows a user to add new functionality to an existing object without altering its structure. This pattern creates a decorator class which wraps the original class and provides additional functionality keeping class methods signature intact.";
IShape circle = new Circle();
IShape redCircle = new RedShapeDecorator(new Circle());
IShape redRectangle = new RedShapeDecorator(new Rectangle());
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.Append("Circle with normal border" + "\n");
stringBuilder.Append(circle.Draw());
stringBuilder.Append("Circle with red border" + "\n");
stringBuilder.Append(redCircle.Draw());
stringBuilder.Append("Rectangle with red border" + "\n");
stringBuilder.Append(redRectangle.Draw());
this.GuiUC.TextBlockText = stringBuilder.ToString();
this.GuiUC.TextBlockConsequence = @"Applicability
To add responsibilities to individual objects dynamically and transparently, that is, without affecting other objects for responsibilities that can be withdrawn
When extension by sub-classing is impractical. Sometimes a large number of independent extensions are possible and would produce an explosion of subclasses to support every combination. Or a class definition may be hidden or otherwise unavailable for sub-classing
Consequences
More flexibility than static inheritance
• Provides a more flexible way to add responsibilities to objects than can be had with static (multiple) inheritance. With decorators responsibilities can be added and removed at runtime simply by attaching and detaching them
Avoids feature-laden classes high up in the hierarchy
• Offers a pay-as-you-go approach to adding responsibilities. Instead of trying to support all foreseeable features in a complex, customizable class, you can define a simple class and add functionality incrementally with Decorator objects. Functionality can be composed from simple pieces. As a result, an application needn't pay for features it doesn't use
A decorator and its component aren't identical
• Acts as a transparent enclosure. But from an object identity point of view, a decorated component is not identical to the component itself. Hence you shouldn't rely on object identity when you use decorators
Lots of little objects
• A design that uses Decorator often results in systems composed of lots of little objects that all look alike. The objects differ only in the way they are interconnected, not in their class or in the value of their variables. Although these systems are easy to customize by those who understand them, they can be hard to learn and debug";
}
