HessianSerializerInput.java

/*
 * 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;
import java.io.InputStream;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.HashMap;

/**
 * Input stream for Hessian requests, deserializing objects using the
 * java.io.Serialization protocol.
 *
 * <p>HessianSerializerInput is unbuffered, so any client needs to provide
 * its own buffering.
 *
 * <h3>Serialization</h3>
 *
 * <pre>
 * InputStream is = new FileInputStream("test.xml");
 * HessianOutput in = new HessianSerializerOutput(is);
 *
 * Object obj = in.readObject();
 * is.close();
 * </pre>
 *
 * <h3>Parsing a Hessian reply</h3>
 *
 * <pre>
 * InputStream is = ...; // from http connection
 * HessianInput in = new HessianSerializerInput(is);
 * String value;
 *
 * in.startReply();         // read reply header
 * value = in.readString(); // read string value
 * in.completeReply();      // read reply footer
 * </pre>
 */
public class HessianSerializerInput extends HessianInput {
  /**
   * Creates a new Hessian input stream, initialized with an
   * underlying input stream.
   *
   * @param is the underlying input stream.
   */
  public HessianSerializerInput(InputStream is)
  {
    super(is);
  }

  /**
   * Creates an uninitialized Hessian input stream.
   */
  public HessianSerializerInput()
  {
  }

  /**
   * Reads an object from the input stream.  cl is known not to be
   * a Map.
   */
  protected Object readObjectImpl(Class cl)
    throws IOException
  {
    try {
      Object obj = cl.newInstance();

      if (_refs == null)
        _refs = new ArrayList();
      _refs.add(obj);

      HashMap fieldMap = getFieldMap(cl);

      int code = read();
      for (; code >= 0 && code != 'z'; code = read()) {
        _peek = code;
        
        Object key = readObject();
        
        Field field = (Field) fieldMap.get(key);

        if (field != null) {
          Object value = readObject(field.getType());
          field.set(obj, value);
        }
        else {
          Object value = readObject();
        }
      }
      
      if (code != 'z')
        throw expect("map", code);

      // if there's a readResolve method, call it
      try {
        Method method = cl.getMethod("readResolve", new Class[0]);
        return method.invoke(obj, new Object[0]);
      } catch (Exception e) {
      }

      return obj;
    } catch (IOException e) {
      throw e;
    } catch (Exception e) {
      throw new IOExceptionWrapper(e);
    }
  }

  /**
   * Creates a map of the classes fields.
   */
  protected HashMap getFieldMap(Class cl)
  {
    HashMap fieldMap = new HashMap();
    
    for (; cl != null; cl = cl.getSuperclass()) {
      Field []fields = cl.getDeclaredFields();
      for (int i = 0; i < fields.length; i++) {
        Field field = fields[i];

        if (Modifier.isTransient(field.getModifiers()) ||
            Modifier.isStatic(field.getModifiers()))
          continue;

        // XXX: could parameterize the handler to only deal with public
        field.setAccessible(true);

        fieldMap.put(field.getName(), field);
      }
    }

    return fieldMap;
  }
}