动态地使用泛型扩展Java类

Question

is possible to use aspectj or javassist for extending a class with a generic class? for example i have a class with:

@someAnnotation(GenerictTypeParameter.class)
public aClass{
  ...
}

so the idea is to search all classes with @someAnnotation and then extending them with another class and get this:

public aClass extends anotherClass<GenericTypeParameter>{
  ...
}

Answer 1

You can do so using Byte Buddy , if you are willing to use another code generation library. With Byte Buddy, you can:

new ByteBuddy()
  .subclass(TypeDescription.Generic.Builder
              .parameterizedType(AnotherClass.class, GenericTypeParameter.class)
              .build())
  .make();

You can simply resolve the relevant type from the annotation. Byte Buddy also allows you to redefine existing types if this is what you are trying to achieve.