/*

  * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH

  *

  * Licensed 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 de.smartics.properties.spi.core.util;

 import java.io.IOException;

 import java.io.ObjectInputStream;

 import java.io.ObjectOutputStream;

 import java.io.Serializable;

 import java.lang.reflect.Method;

 import javax.annotation.CheckForNull;

 import org.apache.commons.lang.ObjectUtils;

 /**

  * Wrapper to serialize {@link Method}s.

  */

 public final class SerializableMethod implements Serializable

 {

   // ********************************* Fields *********************************

   // --- constants ------------------------------------------------------------

   /**

    * The class version identifier.

    */

   private static final long serialVersionUID = 1L;

   // --- members --------------------------------------------------------------

   /**

    * The wrapped method. The method may be <code>null</code>.

    */

   private transient volatile Method method;

   /**

    * Default constructor.

    *

    * @param method the wrapped method. The method may be <code>null</code>.

    */

   public SerializableMethod(final Method method)

   {

     this.method = method;

   }

   // ****************************** Initializer *******************************

   // ****************************** Constructors ******************************

   // ****************************** Inner Classes *****************************

   // ********************************* Methods ********************************

   // --- init -----------------------------------------------------------------

   // --- get&set --------------------------------------------------------------

   /**

    * Returns the wrapped method.

    *

    * @return the wrapped method. The method may be <code>null</code>.

    */

   @CheckForNull

   public Method getMethod()

   {

     return method;

   }

   // --- business -------------------------------------------------------------

   // --- object basics --------------------------------------------------------

   /**

    * Method to write the object to the stream.

    *

    * @param out the stream to write to.

    * @throws IOException on any write problem.

    */

   private void writeObject(final ObjectOutputStream out) throws IOException

   {

     out.defaultWriteObject();

     if (method != null)

     {

       final Class<?> declaringType = method.getDeclaringClass();

       final String methodName = method.getName();

       final Class<?>[] parameterTypes = method.getParameterTypes();

       out.writeObject(declaringType);

       out.writeObject(methodName);

       out.writeObject(parameterTypes);

     }

     else

     {

       out.writeObject(null);

     }

   }

   /**

    * Reads the object from the given stream.

    *

    * @param in the stream to read from.

    * @throws IOException on read problems.

    * @throws ClassNotFoundException if a class cannot be found.

    */

   private void readObject(final ObjectInputStream in) throws IOException,

     ClassNotFoundException

   {

     in.defaultReadObject();

     final Class<?> declaringType = (Class<?>) in.readObject();

     if (declaringType != null)

     {

       final String methodName = (String) in.readObject();

       final Class<?>[] parameterTypes = (Class<?>[]) in.readObject();

       try

       {

         this.method =

             declaringType.getDeclaredMethod(methodName, parameterTypes);

       }

       catch (final Exception e)

       {

         final String message =

             message(declaringType, methodName, parameterTypes);

         throw new IOException(message, e);

       }

     }

     else

     {

       method = null;

     }

   }

   private static String message(final Class<?> declaringType,

       final String methodName, final Class<?>[] parameterTypes)

   {

     final StringBuilder buffer = new StringBuilder(256);

     buffer.append("Cannot recreate method ").append(declaringType.getName())

         .append('.').append(methodName).append('(');

     int counter = parameterTypes.length;

     for (final Class<?> parameterType : parameterTypes)

     {

       buffer.append(parameterType.getName());

       if (--counter > 0)

       {

         buffer.append(", ");

       }

     }

     buffer.append(").");

     return buffer.toString();

   }

   @Override

   public String toString()

   {

     return ObjectUtils.toString(method, null);

   }

 }