package bcelifier;

import org.apache.commons.bcel6.generic.*;
import org.apache.commons.bcel6.classfile.*;
import org.apache.commons.bcel6.*;
import java.io.*;

public class NullCreator implements Constants {
  private InstructionFactory _factory;
  private ConstantPoolGen    _cp;
  private ClassGen           _cg;

  public NullCreator() {
    _cg = new ClassGen("bcelifier.Null", "java.lang.Object", "Null.java", ACC_PUBLIC | ACC_SUPER, new String[] {  });

    _cp = _cg.getConstantPool();
    _factory = new InstructionFactory(_cg, _cp);
  }

  public void create(OutputStream out) throws IOException {
    createFields();
    createMethod_0();
    _cg.getJavaClass().dump(out);
  }

  private void createFields() {
    FieldGen field;

    field = new FieldGen(0, new ObjectType("java.lang.Integer"), "i", _cp);
    _cg.addField(field.getField());
  }

  private void createMethod_0() {
    InstructionList il = new InstructionList();
    MethodGen method = new MethodGen(ACC_PUBLIC, Type.VOID, Type.NO_ARGS, new String[] {  }, "<init>", "bcelifier.Null", il, _cp);

    InstructionHandle ih_0 = il.append(_factory.createLoad(Type.OBJECT, 0));
    il.append(_factory.createInvoke("java.lang.Object", "<init>", Type.VOID, Type.NO_ARGS, Constants.INVOKESPECIAL));
    InstructionHandle ih_4 = il.append(_factory.createLoad(Type.OBJECT, 0));
    il.append(InstructionConstants.ACONST_NULL);
    il.append(_factory.createFieldAccess("bcelifier.Null", "i", new ObjectType("java.lang.Integer"), Constants.PUTFIELD));
    InstructionHandle ih_9 = il.append(_factory.createReturn(Type.VOID));
    method.setMaxStack();
    method.setMaxLocals();
    _cg.addMethod(method.getMethod());
    il.dispose();
  }

  public static void main(String[] args) throws Exception {
    bcelifier.NullCreator creator = new bcelifier.NullCreator();
    creator.create(new FileOutputStream("bcelifier.Null.class"));
  }
}