Re: super object reference

From:

=?windows-1252?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 01 Feb 2015 09:21:04 -0500

Message-ID:

<54ce3657$0$292$14726298@news.sunsite.dk>

On 2/1/2015 9:13 AM, Arne Vajh?j wrote:

On 2/1/2015 6:40 AM, Philipp Kraus wrote:

I see this is a conceptional design error at my code. I use my variable x
within a deeper framewok call and this call runs
x.getclass.getDecalredFields(), but
this returns in the example case nothing, ebcause my child class does
not have any fields.

I have got only the x reference but I need all fields of the object,
also the fields of the child & parent
class and fields of the parent-parent class... I would like to create a
field list from my object x over all
fields that are exists within the objects. IMHO I must run from my
object class up to the java.object and collect all fields.
How can I do this?

You recurse.

First getDeclaredFields() and then getSuperclass() and process that.

Demo:

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;

public class AllFields {
    private static void analyze(Class<?> clz, List<Field> fields) {
        for(Field f : clz.getDeclaredFields()) fields.add(f);
        if(!clz.getSuperclass().equals(Object.class))
analyze(clz.getSuperclass(), fields);
    }
    public static void dump(Object o) {
        System.out.println(o.getClass().getName());
        List<Field> fields = new ArrayList<>();
        analyze(o.getClass(), fields);
        for(Field f : fields) {
            System.out.println(" " + f.getName());
        }
    }
    public static void main(String[] args) {
        dump(new A());
        dump(new B());
        dump(new C());
    }
}

class A {
    private Object a;
}

class B extends A {
    private Object b;
}

class C extends B {
    private Object c;
}

Arne