Zend Server Question:

- The decorator is used to extend the functionality of the class that wraps up the structure.

- The decorator extends the class and its functionality by wrapping up in a defined pattern.

- The use of it allows the user to add or modify the existing behaviour of the API that is same.

- Decorators wrap other that identifies the original object and follows with the same API.

- The WindowDecorator is being created to display the window, by showing scrollbars, window title, etc;

$window = new WindowScrollbarDecorator(
new WindowTitleDecorator(
new WindowDecorator(
new Window()
)
)
);