Java EE 8 Design Patterns and Best Practices

The decorator in a JEE scenario

First of all, we create an Engineering interface that has the business method we want to decorate. We then create an abstract class named BasicEngineering that extends Engineering. As the following code shows, we can make an abstract EngineeringDecorator using two concrete decorators, or we can make two abstract decorator classes that implement Engineering directly. There is no obligation to keep the decorator classes concrete.

For the sake of simplicity, let's create the two decorator classes as abstract, without having to extend them from a basic decorator class. So, both the ElectronicDecorator and MechanicalDecorator classes will decorate the Engineering objects (ElectronicEngineering and MechanicalEngineering ...