/*
 * Copyright (c) 2001-2004 Caucho Technology, Inc.  All rights reserved.
 *
 * The Apache Software License, Version 1.1
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Caucho Technology (http://www.caucho.com/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "Burlap", "Resin", and "Caucho" must not be used to
 *    endorse or promote products derived from this software without prior
 *    written permission. For written permission, please contact
 *    info@caucho.com.
 *
 * 5. Products derived from this software may not be called "Resin"
 *    nor may "Resin" appear in their names without prior written
 *    permission of Caucho Technology.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL CAUCHO TECHNOLOGY OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @author Scott Ferguson
 */

package com.caucho.hessian.io;

import java.io.IOException;

/**
 * Deserializing an object. 
 */
public class AbstractDeserializer implements Deserializer {
  public static final NullDeserializer NULL = new NullDeserializer();
  
  public Class<?> getType()
  {
    return Object.class;
  }

  public boolean isReadResolve()
  {
    return false;
  }

  public Object readObject(AbstractHessianInput in)
    throws IOException
  {
    Object obj = in.readObject();

    String className = getClass().getName();

    if (obj != null)
      throw error(className + ": unexpected object " + obj.getClass().getName() + " (" + obj + ")");
    else
      throw error(className + ": unexpected null value");
  }
  
  public Object readList(AbstractHessianInput in, int length)
    throws IOException
  {
    throw new UnsupportedOperationException(String.valueOf(this));
  }
  
  public Object readLengthList(AbstractHessianInput in, int length)
    throws IOException
  {
    throw new UnsupportedOperationException(String.valueOf(this));
  }
  
  public Object readMap(AbstractHessianInput in)
    throws IOException
  {
    Object obj = in.readObject();

    String className = getClass().getName();

    if (obj != null)
      throw error(className + ": unexpected object " + obj.getClass().getName() + " (" + obj + ")");
    else
      throw error(className + ": unexpected null value");
  }
  
  /**
   * Creates the field array for a class. The default
   * implementation returns a String[] array.
   *
   * @param len number of items in the array
   * @return the new empty array
   */
  public Object []createFields(int len)
  {
    return new String[len];
  }
  
  /**
   * Creates a field value class. The default
   * implementation returns the String.
   *
   * @param len number of items in the array
   * @return the new empty array
   */
  public Object createField(String name)
  {
    return name;
  }
  
  @Override
  public Object readObject(AbstractHessianInput in,
                           String []fieldNames)
    throws IOException
  {
    return readObject(in, (Object []) fieldNames);
  }
  
  /**
   * Reads an object instance from the input stream
   */
  public Object readObject(AbstractHessianInput in, 
                           Object []fields)
    throws IOException
  {
    throw new UnsupportedOperationException(toString());
  }

  protected HessianProtocolException error(String msg)
  {
    return new HessianProtocolException(msg);
  }

  protected String codeName(int ch)
  {
    if (ch < 0)
      return "end of file";
    else
      return "0x" + Integer.toHexString(ch & 0xff);
  }

  /**
   * The NullDeserializer exists as a marker for the factory classes so
   * they save a null result.
   */
  static final class NullDeserializer extends AbstractDeserializer {
  }
}
