private Statement makeMethodBody(
      ClassNode classNode, MethodSignature methodSignature, Parameter[] parameters) {
    String invokeMethod = methodSignature.isStatic() ? "invokeStatic" : "invokeInstance";
    Expression[] args = new Expression[parameters.length + 2];
    args[0] =
        methodSignature.isStatic()
            ? new ClassExpression(classNode)
            : VariableExpression.THIS_EXPRESSION;
    args[1] = new ConstantExpression(methodSignature.getMethodName());
    int i = 2;
    for (Parameter parameter : parameters) {
      args[i++] = new VariableExpression(parameter.getName());
    }

    return returns(call(getDomainHandlerMethod(classNode), invokeMethod, args(args)));
  }
  public static void apply(ClassNode declaringClass) {
    injectInterface(declaringClass, MYBATIS_CONTRIBUTION_HANDLER_CNODE);

    // add field:
    // protected MybatisProvider this$MybatisProvider = DefaultMybatisProvider.instance
    FieldNode providerField =
        declaringClass.addField(
            MYBATIS_PROVIDER_FIELD_NAME,
            ACC_PRIVATE | ACC_SYNTHETIC,
            MYBATIS_PROVIDER_CNODE,
            defaultMybatisProviderInstance());

    // add method:
    // MybatisProvider getMybatisProvider() {
    //     return this$MybatisProvider
    // }
    injectMethod(
        declaringClass,
        new MethodNode(
            METHOD_GET_MYBATIS_PROVIDER,
            ACC_PUBLIC,
            MYBATIS_PROVIDER_CNODE,
            Parameter.EMPTY_ARRAY,
            NO_EXCEPTIONS,
            returns(field(providerField))));

    // add method:
    // void setMybatisProvider(MybatisProvider provider) {
    //     this$MybatisProvider = provider ?: DefaultMybatisProvider.instance
    // }
    injectMethod(
        declaringClass,
        new MethodNode(
            METHOD_SET_MYBATIS_PROVIDER,
            ACC_PUBLIC,
            ClassHelper.VOID_TYPE,
            params(param(MYBATIS_PROVIDER_CNODE, PROVIDER)),
            NO_EXCEPTIONS,
            block(
                ifs_no_return(
                    cmp(var(PROVIDER), ConstantExpression.NULL),
                    assigns(field(providerField), defaultMybatisProviderInstance()),
                    assigns(field(providerField), var(PROVIDER))))));

    for (MethodNode method : MYBATIS_CONTRIBUTION_HANDLER_CNODE.getMethods()) {
      if (Arrays.binarySearch(DELEGATING_METHODS, method.getName()) < 0) continue;
      List<Expression> variables = new ArrayList<Expression>();
      Parameter[] parameters = new Parameter[method.getParameters().length];
      for (int i = 0; i < method.getParameters().length; i++) {
        Parameter p = method.getParameters()[i];
        parameters[i] = new Parameter(makeClassSafe(p.getType()), p.getName());
        parameters[i].getType().setGenericsTypes(p.getType().getGenericsTypes());
        variables.add(var(p.getName()));
      }
      ClassNode returnType = makeClassSafe(method.getReturnType());
      returnType.setGenericsTypes(method.getReturnType().getGenericsTypes());
      returnType.setGenericsPlaceHolder(method.getReturnType().isGenericsPlaceHolder());

      MethodNode newMethod =
          new MethodNode(
              method.getName(),
              ACC_PUBLIC,
              returnType,
              parameters,
              NO_EXCEPTIONS,
              returns(call(field(providerField), method.getName(), args(variables))));
      newMethod.setGenericsTypes(method.getGenericsTypes());
      injectMethod(declaringClass, newMethod);
    }
  }