Create dynamic class error

[heyyaitsl]

Hello,

I want to create a dynamic class that implements an interface. This interface has four void methods. I try to do it with byte buddy but I get an error in my way of implimenting it. I have tried to find a solution, but I can't find anything that works for my problem, so below I pass the code and the exact error it gives me.

I have this Interface:

---

import javafx.scene.canvas.GraphicsContext;
import net.bytebuddy.implementation.bind.annotation.RuntimeType;

public interface Figura {


    public void setXYTamano(int x, int  y, int tamano);

    public void dibujar(GraphicsContext gc);


    public void mover();


    public void agrandar();

}

---

Then, I have this code for the dynamic class:

---

package javafxapplication1.acciones;


import net.bytebuddy.ByteBuddy;
import net.bytebuddy.description.modifier.Visibility;
import net.bytebuddy.dynamic.loading.ClassLoadingStrategy;
import net.bytebuddy.implementation.MethodDelegation;
import net.bytebuddy.implementation.bind.annotation.AllArguments;
import net.bytebuddy.implementation.bind.annotation.RuntimeType;
import net.bytebuddy.matcher.ElementMatchers;

import static net.bytebuddy.matcher.ElementMatchers.named;

public class CreateClass{
    Class<? extends Figura> claseDinamica = null;
    public void crearClaseRectangulo () throws InstantiationException, IllegalAccessException {
        try {
            claseDinamica = new ByteBuddy()
                    .subclass(Figura.class)
                    .name("Rectangulo")
                    .defineField("x", int.class, Visibility.PRIVATE)
                    .defineField("y", int.class, Visibility.PRIVATE)
                    .defineField("tamano", int.class, Visibility.PRIVATE)
                    .method(ElementMatchers.is(named("setXYTamano")))
                    .intercept(MethodDelegation.to(Interceptor.class))
                    .method(ElementMatchers.is(named("dibujar")))
                    .intercept(MethodDelegation.to(Interceptor.class))
                    .method(ElementMatchers.is(named("mover")))
                    .intercept(MethodDelegation.to(Interceptor.class))
                    .method(ElementMatchers.is(named("agrandar")))
                    .intercept(MethodDelegation.to(Interceptor.class))
                    .make()
                    .load(CreateClass.class.getClassLoader(), ClassLoadingStrategy.Default.WRAPPER)
                    .getLoaded();

        }catch (Exception e) {
            // Manejo de excepciones
            e.printStackTrace();
        }

    }
    public static class Interceptor{

        @RuntimeType
        public void setXYTamano(@AllArguments Object [] arguments) {
            //implementation
        }
        @RuntimeType
        public void dibujar(@AllArguments Object [] arguments){
            //implementation
        }

        @RuntimeType
        public void mover(@AllArguments Object [] arguments){
           //implementation
        }

        @RuntimeType
        public void agrandar(@AllArguments Object [] arguments){
            //implementation
        }
    }


   public Figura getInstance() throws InstantiationException, IllegalAccessException {
        if (claseDinamica != null){
            return claseDinamica.newInstance();
        }
        return null;
    }


}

---

When I try to create "Rectangulo" instance, I get this error:

---

GRAVE: null
java.lang.NullPointerException
	at javafxapplication1.PantallaController.lambda$initialize$5(PantallaController.java:142)

---

I have checked what I am creating in a file, and it creates a class without its methods.

I am using Java 8 and Byte Buddy 1.10.22.

Why might this be happening? Can anyone help me? Thanks.

@raphw

[raphw]

I do not think that this is doing what you intend. With (MethodDelegation.to(Interceptor.class), you delegate to a static method. You likely want to delegate to an instance. Rather define a field with an Interceptor and then delegate via MethodDelegation.toField(...).

[suyunfei]

Wow Your email format is really nice

…

2023年11月21日 05:41，Laura Sarmiento Cárdenes ***@***.***> 写道： Hello, I want to create a dynamic class that implements an interface. This interface has four void methods. I try to do it with byte buddy but I get an error in my way of implimenting it. I have tried to find a solution, but I can't find anything that works for my problem, so below I pass the code and the exact error it gives me. I have this Interface: import javafx.scene.canvas.GraphicsContext; import net.bytebuddy.implementation.bind.annotation.RuntimeType; public interface Figura { public void setXYTamano(int x, int y, int tamano); public void dibujar(GraphicsContext gc); public void mover(); public void agrandar(); } Then, I have this code for the dynamic class: package javafxapplication1.acciones; import net.bytebuddy.ByteBuddy; import net.bytebuddy.description.modifier.Visibility; import net.bytebuddy.dynamic.loading.ClassLoadingStrategy; import net.bytebuddy.implementation.MethodDelegation; import net.bytebuddy.implementation.bind.annotation.AllArguments; import net.bytebuddy.implementation.bind.annotation.RuntimeType; import net.bytebuddy.matcher.ElementMatchers; import static net.bytebuddy.matcher.ElementMatchers.named; public class CreateClass{ Class<? extends Figura> claseDinamica = null; public void crearClaseRectangulo () throws InstantiationException, IllegalAccessException { try { claseDinamica = new ByteBuddy() .subclass(Figura.class) .name("Rectangulo") .defineField("x", int.class, Visibility.PRIVATE) .defineField("y", int.class, Visibility.PRIVATE) .defineField("tamano", int.class, Visibility.PRIVATE) .method(ElementMatchers.is(named("setXYTamano"))) .intercept(MethodDelegation.to(Interceptor.class)) .method(ElementMatchers.is(named("dibujar"))) .intercept(MethodDelegation.to(Interceptor.class)) .method(ElementMatchers.is(named("mover"))) .intercept(MethodDelegation.to(Interceptor.class)) .method(ElementMatchers.is(named("agrandar"))) .intercept(MethodDelegation.to(Interceptor.class)) .make() .load(CreateClass.class.getClassLoader(), ClassLoadingStrategy.Default.WRAPPER) .getLoaded(); }catch (Exception e) { // Manejo de excepciones e.printStackTrace(); } } public static class Interceptor{ @RuntimeType public void ***@***.*** Object [] arguments) { //implementation } @RuntimeType public void ***@***.*** Object [] arguments){ //implementation } @RuntimeType public void ***@***.*** Object [] arguments){ //implementation } @RuntimeType public void ***@***.*** Object [] arguments){ //implementation } } public Figura getInstance() throws InstantiationException, IllegalAccessException { if (claseDinamica != null){ return claseDinamica.newInstance(); } return null; } } When I try to create "Rectangulo" instance, I get this error: GRAVE: null java.lang.NullPointerException at javafxapplication1.PantallaController.lambda$initialize$5(PantallaController.java:142) I have checked what I am creating in a file, and it creates a class without its methods. I am using Java 8 and Byte Buddy 1.10.22. Why might this be happening? Can anyone help me? Thanks. @raphw <https://github.com/raphw> — Reply to this email directly, view it on GitHub <#1563>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADCC5KLUDMBARZUFRK6IXF3YFPFBPAVCNFSM6AAAAAA7TR4VY2VHI2DSMVQWIX3LMV43ERDJONRXK43TNFXW4OZVHA3TGNZTG4>. You are receiving this because you are subscribed to this thread.