How to get super fields in Lombok annotation handler

Question

I want to modify the format of Lombok @ToString to make it behave like the toString code generated by IDEA. There is no option available so I try to modify Lombok source code lombok.javac.handlers.HandleToString.java. I want to get fields of parents till Object then join them with ", " but I can't find way to achieve it.

Now I can only reluctantly achieve it by recursion and String.substring method, but it is not very general. One of the decompilation results with my modified Lombok is as follows:

public String toString() {
        String varSuperToString = super.toString();
        int varStart = varSuperToString.indexOf("{") + 1;
        int varEnd = varSuperToString.lastIndexOf("}");
        String varSuperSub = "";

        try {
            varSuperSub = varSuperToString.substring(varStart, varEnd);
        } catch (StringIndexOutOfBoundsException var6) {
        }

        if (!varSuperSub.isEmpty()) {
            varSuperSub = varSuperSub + ", ";
        }

        return "NonEmptyChild_NonEmptyParent{" + varSuperSub + "email=" + this.email + ", " + "city=" + this.city + "}";
    }

Lombok's toString: NonEmptyChild_NonEmptyParent(super=NonEmptyParent(id=8, name=zfff), [email protected], city=bj)

But I want: NonEmptyChild_NonEmptyParent{id=8, name=zfff, [email protected], city=bj}

I think I need to get fields of parents till Object in Lombok annotation processor, but I don't how to get them. Can you help me please?

Answer 1

Specify callSuper=true for calling super class toString

 @ToString(callSuper=true)

Using lombook annotation you cannot change the pattern, if you need any pattern changes you have to override the toString, Since super class fields are non private you can access them directly using this keyword

@Override
public String toString() {
    return "TestModel {id=" + this.id +"name= "+this.name+"email= "+this.email+"city= "+this.city+ "}";
}

Answer 2

Annotation processors like Lombok only have access to the compilation unit (i.e. Java file) that they are currently processing. They cannot access any superclass of the processed unit. That means that all generated code must solely rely on local information, and thus the superclass's fields can only be printed by the superclass's toString().

The only way is to make Lombok generate some ugly string replacement code that removes the classname and the parentheses from the result of the super.toString() call. But you really should not do that. (Remember that you also have to change it for the Eclipse generator and in the IntelliJ plugin.)

NB: If something else relies on your toString() implementation, you should implement it manually to make that clear. If not, it's better to live with an imperfect format than to hack Lombok.