BeanSerializer.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.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.logging.*;

/**
 * Serializing an object for known object types.
 */
public class BeanSerializer extends AbstractSerializer {
  private static final Logger log
    = Logger.getLogger(BeanSerializer.class.getName());
  
  private static final Object []NULL_ARGS = new Object[0];
  private Method []_methods;
  private String []_names;

  private Object _writeReplaceFactory;
  private Method _writeReplace;
  
  public BeanSerializer(Class cl)
  {
    introspectWriteReplace(cl);

    ArrayList primitiveMethods = new ArrayList();
    ArrayList compoundMethods = new ArrayList();
    
    for (; cl != null; cl = cl.getSuperclass()) {
      Method []methods = cl.getDeclaredMethods();
      
      for (int i = 0; i < methods.length; i++) {
	Method method = methods[i];

	if (Modifier.isStatic(method.getModifiers()))
	  continue;

	if (method.getParameterTypes().length != 0)
	  continue;

	String name = method.getName();

	if (! name.startsWith("get"))
	  continue;

	Class type = method.getReturnType();

	if (type.equals(void.class))
	  continue;

	if (findSetter(methods, name, type) == null)
	  continue;

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

	if (type.isPrimitive() ||
	    type.getName().startsWith("java.lang.") &&
	    ! type.equals(Object.class))
	  primitiveMethods.add(method);
	else
	  compoundMethods.add(method);
      }
    }

    ArrayList methodList = new ArrayList();
    methodList.addAll(primitiveMethods);
    methodList.addAll(compoundMethods);

    _methods = new Method[methodList.size()];
    methodList.toArray(_methods);

    _names = new String[_methods.length];
    
    for (int i = 0; i < _methods.length; i++) {
      String name = _methods[i].getName();

      name = name.substring(3);

      int j = 0;
      for (; j < name.length() && Character.isUpperCase(name.charAt(j)); j++) {
      }

      if (j == 1)
	name = name.substring(0, j).toLowerCase() + name.substring(j);
      else if (j > 1)
	name = name.substring(0, j - 1).toLowerCase() + name.substring(j - 1);

      _names[i] = name;
    }
  }

  private void introspectWriteReplace(Class cl)
  {
    try {
      ClassLoader loader = Thread.currentThread().getContextClassLoader();

      String className = cl.getName() + "HessianSerializer";

      Class serializerClass = Class.forName(className, false, loader);

      Object serializerObject = serializerClass.newInstance();

      Method writeReplace = getWriteReplace(serializerClass, cl);

      if (writeReplace != null) {
	_writeReplaceFactory = serializerObject;
	_writeReplace = writeReplace;

	return;
      }
    } catch (ClassNotFoundException e) {
    } catch (Exception e) {
      log.log(Level.FINER, e.toString(), e);
    }
      
    _writeReplace = getWriteReplace(cl);
  }

  /**
   * Returns the writeReplace method
   */
  protected Method getWriteReplace(Class cl)
  {
    for (; cl != null; cl = cl.getSuperclass()) {
      Method []methods = cl.getDeclaredMethods();
      
      for (int i = 0; i < methods.length; i++) {
	Method method = methods[i];

	if (method.getName().equals("writeReplace") &&
	    method.getParameterTypes().length == 0)
	  return method;
      }
    }

    return null;
  }

  /**
   * Returns the writeReplace method
   */
  protected Method getWriteReplace(Class cl, Class param)
  {
    for (; cl != null; cl = cl.getSuperclass()) {
      for (Method method : cl.getDeclaredMethods()) {
	if (method.getName().equals("writeReplace")
	    && method.getParameterTypes().length == 1
	    && param.equals(method.getParameterTypes()[0]))
	  return method;
      }
    }

    return null;
  }
  
  public void writeObject(Object obj, AbstractHessianOutput out)
    throws IOException
  {
    if (out.addRef(obj))
      return;
    
    Class cl = obj.getClass();
    
    try {
      if (_writeReplace != null) {
	Object repl;

	if (_writeReplaceFactory != null)
	  repl = _writeReplace.invoke(_writeReplaceFactory, obj);
	else
	  repl = _writeReplace.invoke(obj);

	out.removeRef(obj);

	out.writeObject(repl);

	out.replaceRef(repl, obj);

	return;
      }
    } catch (Exception e) {
      log.log(Level.FINER, e.toString(), e);
    }

    int ref = out.writeObjectBegin(cl.getName());

    if (ref < -1) {
      // Hessian 1.1 uses a map
      
      for (int i = 0; i < _methods.length; i++) {
	Method method = _methods[i];
	Object value = null;

	try {
	  value = _methods[i].invoke(obj, (Object []) null);
	} catch (Exception e) {
	  log.log(Level.FINE, e.toString(), e);
	}

	out.writeString(_names[i]);
	
	out.writeObject(value);
      }
      
      out.writeMapEnd();
    }
    else {
      if (ref == -1) {
	out.writeInt(_names.length);
	
	for (int i = 0; i < _names.length; i++)
	  out.writeString(_names[i]);
	
	out.writeObjectBegin(cl.getName());
      }

      for (int i = 0; i < _methods.length; i++) {
	Method method = _methods[i];
	Object value = null;

	try {
	  value = _methods[i].invoke(obj, (Object []) null);
	} catch (Exception e) {
	  log.log(Level.FINER, e.toString(), e);
	}
	
	out.writeObject(value);
      }
    }
  }

  /**
   * Finds any matching setter.
   */
  private Method findSetter(Method []methods, String getterName, Class arg)
  {
    String setterName = "set" + getterName.substring(3);
    
    for (int i = 0; i < methods.length; i++) {
      Method method = methods[i];

      if (! method.getName().equals(setterName))
	continue;
      
      if (! method.getReturnType().equals(void.class))
	continue;

      Class []params = method.getParameterTypes();

      if (params.length == 1 && params[0].equals(arg))
	return method;
    }

    return null;
  }
}