What are Decorators in the Zend framework?

Zend framework utilizes the decorator pattern to render elements and forms. The decorator is quite generally used to comply with the single responsibility principle as it admits functionality to be divided in between classes with unique areas of concern. One basic technique to define a common decorator pattern is a design that allows the behavior to be added to a particular object, either statically or dynamically, without having any effect on the behavior of various other objects from the same class.