Java EE 8 Design Patterns and Best Practices

Decorator implementation 

The following code shows the MechanicalDecorator and the ElectronicDecorator decorator classes:

@Decoratorpublic abstract class MechanicalDecorator implements Engineering {   @Mechanical   @Any   @Inject   @Delegate   Engineering engineering;   @Override   public List<String> getDisciplines() {      System.out.println("Decorating Mechanical Engineering");      List<String> disciplines = new ArrayList<>      (engineering.getDisciplines());      disciplines.addAll (Arrays.asList("d31", "d37", "d33", "d34",       "d32"));      return disciplines;    }}@Decoratorpublic abstract class EngineeringDecorator implements Engineering {   @Electronic   @Any   @Inject   @Delegate   Engineering engineering;   @Override   public List<String> getDisciplines() { System.out.println("Decorating ...