/*
    * 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
    *
   *   http://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.jcs.jcache.proxy;
  
  import java.lang.reflect.Constructor;
  import java.lang.reflect.InvocationHandler;
  import java.lang.reflect.InvocationTargetException;
  import java.lang.reflect.Method;
  import java.lang.reflect.Proxy;
  
  public class ExceptionWrapperHandler<T> implements InvocationHandler
  {
      private final T delegate;
      private final Constructor<? extends RuntimeException> wrapper;
  
      public ExceptionWrapperHandler(final T delegate, final Class<? extends RuntimeException> exceptionType)
      {
          this.delegate = delegate;
          try
          {
              this.wrapper = exceptionType.getConstructor(Throwable.class);
          }
          catch (final NoSuchMethodException e)
          {
              throw new IllegalStateException(e);
          }
      }
  
      @Override
      public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable
      {
          try
          {
              return method.invoke(delegate, args);
          }
          catch (final InvocationTargetException ite)
          {
              final Throwable e = ite.getCause();
              if (RuntimeException.class.isInstance(e))
              {
                  final RuntimeException re;
                  try
                  {
                      re = wrapper.newInstance(e);
                  }
                  catch (final Exception e1)
                  {
                      throw new IllegalArgumentException(e1);
                  }
                  throw re;
              }
              throw e;
          }
      }
  
      public static <T> T newProxy(final ClassLoader loader, final T delegate, final Class<? extends RuntimeException> exceptionType,
              final Class<T> apis)
      {
          return (T) Proxy.newProxyInstance(loader, new Class<?>[] { apis }, new ExceptionWrapperHandler<T>(delegate, exceptionType));
      }
  }