How to create a default constructor with ByteBuddy?











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1
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I use ByteBuddy and I have this code:



public class A extends B {
public A(String a) {
super(a);
}

public String getValue() {
return "HARDCODED VALUE";
}
}

public abstract class B {
private final String message;

protected B(String message) {
this.message = message;
}

public String getMessage() {
return message;
}
}


My current generation code is:



Constructor<T> declaredConstructor;

try {
declaredConstructor = A.class.getDeclaredConstructor(String.class);
} catch (NoSuchMethodException e) {
//fail with exception..
}

new ByteBuddy()
.subclass(A.class, Default.IMITATE_SUPER_CLASS)
.name(A.class.getCanonicalName() + "$Generated")
.defineConstructor(Visibility.PUBLIC)
.intercept(MethodCall.invoke(declaredConstructor).with("message"))
.make()
.load(tClass.getClassLoader(),ClassLoadingStrategy.Default.WRAPPER)
.getLoaded()
.newInstance();


I want to get instance of class A, and also I want to make some actions in constructor after invoke super(), like this:



public A(){
super("message");

// do something special..
}


I tried implement with MethodDelegation.to(DefaultConstructorInterceptor.class), but I didn't succeed.










share|improve this question




























    up vote
    1
    down vote

    favorite












    I use ByteBuddy and I have this code:



    public class A extends B {
    public A(String a) {
    super(a);
    }

    public String getValue() {
    return "HARDCODED VALUE";
    }
    }

    public abstract class B {
    private final String message;

    protected B(String message) {
    this.message = message;
    }

    public String getMessage() {
    return message;
    }
    }


    My current generation code is:



    Constructor<T> declaredConstructor;

    try {
    declaredConstructor = A.class.getDeclaredConstructor(String.class);
    } catch (NoSuchMethodException e) {
    //fail with exception..
    }

    new ByteBuddy()
    .subclass(A.class, Default.IMITATE_SUPER_CLASS)
    .name(A.class.getCanonicalName() + "$Generated")
    .defineConstructor(Visibility.PUBLIC)
    .intercept(MethodCall.invoke(declaredConstructor).with("message"))
    .make()
    .load(tClass.getClassLoader(),ClassLoadingStrategy.Default.WRAPPER)
    .getLoaded()
    .newInstance();


    I want to get instance of class A, and also I want to make some actions in constructor after invoke super(), like this:



    public A(){
    super("message");

    // do something special..
    }


    I tried implement with MethodDelegation.to(DefaultConstructorInterceptor.class), but I didn't succeed.










    share|improve this question


























      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      I use ByteBuddy and I have this code:



      public class A extends B {
      public A(String a) {
      super(a);
      }

      public String getValue() {
      return "HARDCODED VALUE";
      }
      }

      public abstract class B {
      private final String message;

      protected B(String message) {
      this.message = message;
      }

      public String getMessage() {
      return message;
      }
      }


      My current generation code is:



      Constructor<T> declaredConstructor;

      try {
      declaredConstructor = A.class.getDeclaredConstructor(String.class);
      } catch (NoSuchMethodException e) {
      //fail with exception..
      }

      new ByteBuddy()
      .subclass(A.class, Default.IMITATE_SUPER_CLASS)
      .name(A.class.getCanonicalName() + "$Generated")
      .defineConstructor(Visibility.PUBLIC)
      .intercept(MethodCall.invoke(declaredConstructor).with("message"))
      .make()
      .load(tClass.getClassLoader(),ClassLoadingStrategy.Default.WRAPPER)
      .getLoaded()
      .newInstance();


      I want to get instance of class A, and also I want to make some actions in constructor after invoke super(), like this:



      public A(){
      super("message");

      // do something special..
      }


      I tried implement with MethodDelegation.to(DefaultConstructorInterceptor.class), but I didn't succeed.










      share|improve this question















      I use ByteBuddy and I have this code:



      public class A extends B {
      public A(String a) {
      super(a);
      }

      public String getValue() {
      return "HARDCODED VALUE";
      }
      }

      public abstract class B {
      private final String message;

      protected B(String message) {
      this.message = message;
      }

      public String getMessage() {
      return message;
      }
      }


      My current generation code is:



      Constructor<T> declaredConstructor;

      try {
      declaredConstructor = A.class.getDeclaredConstructor(String.class);
      } catch (NoSuchMethodException e) {
      //fail with exception..
      }

      new ByteBuddy()
      .subclass(A.class, Default.IMITATE_SUPER_CLASS)
      .name(A.class.getCanonicalName() + "$Generated")
      .defineConstructor(Visibility.PUBLIC)
      .intercept(MethodCall.invoke(declaredConstructor).with("message"))
      .make()
      .load(tClass.getClassLoader(),ClassLoadingStrategy.Default.WRAPPER)
      .getLoaded()
      .newInstance();


      I want to get instance of class A, and also I want to make some actions in constructor after invoke super(), like this:



      public A(){
      super("message");

      // do something special..
      }


      I tried implement with MethodDelegation.to(DefaultConstructorInterceptor.class), but I didn't succeed.







      java code-generation byte-buddy






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 9 at 10:36

























      asked Nov 9 at 7:45









      Sergey

      4015




      4015
























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          The JVM requires you to hard-code the super method call into a method what is not possible using delegation (also see the javadoc), this is why you cannot use the MethodDelegation to invoke the constructor. What you can do is to chain the method call you already have and the delegation by using composition by the andThen step as in:



          MethodCall.invoke(declaredConstructor).with("message")
          .andThen(MethodDelegation.to(DefaultConstructorInterceptor.class));





          share|improve this answer





















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            up vote
            1
            down vote













            The JVM requires you to hard-code the super method call into a method what is not possible using delegation (also see the javadoc), this is why you cannot use the MethodDelegation to invoke the constructor. What you can do is to chain the method call you already have and the delegation by using composition by the andThen step as in:



            MethodCall.invoke(declaredConstructor).with("message")
            .andThen(MethodDelegation.to(DefaultConstructorInterceptor.class));





            share|improve this answer

























              up vote
              1
              down vote













              The JVM requires you to hard-code the super method call into a method what is not possible using delegation (also see the javadoc), this is why you cannot use the MethodDelegation to invoke the constructor. What you can do is to chain the method call you already have and the delegation by using composition by the andThen step as in:



              MethodCall.invoke(declaredConstructor).with("message")
              .andThen(MethodDelegation.to(DefaultConstructorInterceptor.class));





              share|improve this answer























                up vote
                1
                down vote










                up vote
                1
                down vote









                The JVM requires you to hard-code the super method call into a method what is not possible using delegation (also see the javadoc), this is why you cannot use the MethodDelegation to invoke the constructor. What you can do is to chain the method call you already have and the delegation by using composition by the andThen step as in:



                MethodCall.invoke(declaredConstructor).with("message")
                .andThen(MethodDelegation.to(DefaultConstructorInterceptor.class));





                share|improve this answer












                The JVM requires you to hard-code the super method call into a method what is not possible using delegation (also see the javadoc), this is why you cannot use the MethodDelegation to invoke the constructor. What you can do is to chain the method call you already have and the delegation by using composition by the andThen step as in:



                MethodCall.invoke(declaredConstructor).with("message")
                .andThen(MethodDelegation.to(DefaultConstructorInterceptor.class));






                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 10 at 16:39









                Rafael Winterhalter

                27.3k1364142




                27.3k1364142






























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