/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You under the Apache License, Version 2.0
    * (the "License"); you may not use this file except in compliance with
    * the License.  You may obtain a copy of the License at
    *
    *      https://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.commons.lang3.builder;
  
  import org.objectweb.asm.ClassWriter;
  import org.objectweb.asm.MethodVisitor;
  import org.objectweb.asm.Opcodes;
  
  /**
   * Builds classes dynamically for tests.
   */
  public class TestClassBuilder {
  
      /**
       * Extends {@link ClassLoader} to make {@link ClassLoader#defineClass(String, byte[])} public.
       */
      static final class DynamicClassLoader extends ClassLoader {
          public Class<?> defineClass(final String name, final byte[] b) {
              return defineClass(name, b, 0, b.length);
          }
      }
  
      /**
       * Defines the simplest possible class.
       *
       * @param name The class name.
       * @return The new class.
       */
      static Class<?> defineSimpleClass(final String name) {
          final ClassWriter classWriter = new ClassWriter(ClassWriter.COMPUTE_FRAMES | ClassWriter.COMPUTE_MAXS);
          classWriter.visit(Opcodes.V1_8, Opcodes.ACC_PUBLIC, name, null, "java/lang/Object", new String[] {});
          final MethodVisitor ctor = classWriter.visitMethod(Opcodes.ACC_PUBLIC, "<init>", "()V", null, null);
          ctor.visitCode();
          ctor.visitVarInsn(Opcodes.ALOAD, 0);
          ctor.visitMethodInsn(Opcodes.INVOKESPECIAL, "java/lang/Object", "<init>", "()V", false);
          ctor.visitInsn(Opcodes.RETURN);
          ctor.visitMaxs(1, 1);
          return new DynamicClassLoader().defineClass(name.replace('/', '.'), classWriter.toByteArray());
      }
  
      static Class<?> defineSimpleClass(final String packageName, final int i) {
          return defineSimpleClass(packageName.replace('.', '/') + "/C" + i);
      }
  
  }