hessianoutput.java

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/*
 * Copyright (c) 2001-2008 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
 *    [e-mail].
 *
 * 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.OutputStream;
import java.util.IdentityHashMap;

/**
 * Output stream for Hessian requests, compatible with microedition
 * Java.  It only uses classes and types available in JDK.
 *
 * <p>Since HessianOutput does not depend on any classes other than
 * in the JDK, it can be extracted independently into a smaller package.
 *
 * <p>HessianOutput is unbuffered, so any client needs to provide
 * its own buffering.
 *
 * <pre>
 * OutputStream os = ...; // from http connection
 * HessianOutput out = new HessianOutput(os);
 * String value;
 *
 * out.startCall("hello");  // start hello call
 * out.writeString("arg1"); // write a string argument
 * out.completeCall();      // complete the call
 * </pre>
 */
public class HessianOutput extends AbstractHessianOutput {
  // the output stream/
  protected OutputStream os;
  // map of references
  private IdentityHashMap _refs;
  private int _version = 1;
  
  /**
   * Creates a new Hessian output stream, initialized with an
   * underlying output stream.
   *
   * @param os the underlying output stream.
   */
  public HessianOutput(OutputStream os)
  {
    init(os);
  }

  /**
   * Creates an uninitialized Hessian output stream.
   */
  public HessianOutput()
  {
  }

  /**
   * Initializes the output
   */
  public void init(OutputStream os)
  {
    this.os = os;

    _refs = null;

    if (_serializerFactory == null)
      _serializerFactory = new SerializerFactory();
  }

  /**
   * Sets the client's version.
   */
  public void setVersion(int version)
  {
    _version = version;
  }

  /**
   * Writes a complete method call.
   */
  public void call(String method, Object []args)
    throws IOException
  {
    startCall(method);
    
    if (args != null) {
      for (int i = 0; i < args.length; i++)
        writeObject(args[i]);
    }
    
    completeCall();
  }

  /**
   * Starts the method call.  Clients would use <code>startCall</code>
   * instead of <code>call</code> if they wanted finer control over
   * writing the arguments, or needed to write headers.
   *
   * <code><pre>
   * c major minor
   * m b16 b8 method-name
   * </pre></code>
   *
   * @param method the method name to call.
   */
  public void startCall(String method)
    throws IOException
  {
    os.write('c');
    os.write(_version);
    os.write(0);

    os.write('m');
    int len = method.length();
    os.write(len >> 8);
    os.write(len);
    printString(method, 0, len);
  }

  /**
   * Writes the call tag.  This would be followed by the
   * headers and the method tag.
   *
   * <code><pre>
   * c major minor
   * </pre></code>
   *
   * @param method the method name to call.
   */
  public void startCall()
    throws IOException
  {
    os.write('c');
    os.write(0);
    os.write(1);
  }

  /**
   * Writes the method tag.
   *
   * <code><pre>
   * m b16 b8 method-name
   * </pre></code>
   *
   * @param method the method name to call.
   */
  public void writeMethod(String method)
    throws IOException
  {
    os.write('m');
    int len = method.length();
    os.write(len >> 8);
    os.write(len);
    printString(method, 0, len);
  }

  /**
   * Completes.
   *
   * <code><pre>
   * z
   * </pre></code>
   */
  public void completeCall()
    throws IOException
  {
    os.write('z');
  }

  /**
   * Starts the reply
   *
   * <p>A successful completion will have a single value:
   *
   * <pre>
   * r
   * </pre>
   */
  public void startReply()
    throws IOException
  {
    os.write('r');
    os.write(1);
    os.write(0);
  }

  /**
   * Completes reading the reply
   *
   * <p>A successful completion will have a single value:
   *
   * <pre>
   * z
   * </pre>
   */
  public void completeReply()
    throws IOException
  {
    os.write('z');
  }

  /**
   * Writes a header name.  The header value must immediately follow.
   *
   * <code><pre>
   * H b16 b8 foo <em>value</em>
   * </pre></code>
   */
  public void writeHeader(String name)
    throws IOException
  {
    int len = name.length();
    
    os.write('H');
    os.write(len >> 8);
    os.write(len);

    printString(name);
  }

  /**
   * Writes a fault.  The fault will be written
   * as a descriptive string followed by an object:
   *
   * <code><pre>
   * f
   * &lt;string>code
   * &lt;string>the fault code
   *
   * &lt;string>message
   * &lt;string>the fault mesage
   *
   * &lt;string>detail
   * mt\x00\xnnjavax.ejb.FinderException
   *     ...
   * z
   * z
   * </pre></code>
   *
   * @param code the fault code, a three digit
   */
  public void writeFault(String code, String message, Object detail)
    throws IOException
  {
    os.write('f');
    writeString("code");
    writeString(code);

    writeString("message");
    writeString(message);

    if (detail != null) {
      writeString("detail");
      writeObject(detail);
    }
    os.write('z');
  }

  /**
   * Writes any object to the output stream.
   */
  public void writeObject(Object object)
    throws IOException
  {
    if (object == null) {
      writeNull();
      return;
    }

    Serializer serializer;

    serializer = _serializerFactory.getSerializer(object.getClass());

    serializer.writeObject(object, this);
  }

  /**
   * Writes the list header to the stream.  List writers will call
   * <code>writeListBegin</code> followed by the list contents and then
   * call <code>writeListEnd</code>.
   *
   * <code><pre>
   * V
   * t b16 b8 type
   * l b32 b24 b16 b8
   * </pre></code>
   */
  public boolean writeListBegin(int length, String type)
    throws IOException
  {
    os.write('V');

    if (type != null) {
      os.write('t');
      printLenString(type);
    }

    if (length >= 0) {
      os.write('l');
      os.write(length >> 24);
      os.write(length >> 16);
      os.write(length >> 8);
      os.write(length);
    }

    return true;
  }

  /**
   * Writes the tail of the list to the stream.
   */
  public void writeListEnd()
    throws IOException
  {
    os.write('z');
  }

  /**
   * Writes the map header to the stream.  Map writers will call
   * <code>writeMapBegin</code> followed by the map contents and then
   * call <code>writeMapEnd</code>.
   *
   * <code><pre>
   * Mt b16 b8 (<key> <value>)z
   * </pre></code>
   */
  public void writeMapBegin(String type)
    throws IOException
  {
    os.write('M');
    os.write('t');
    printLenString(type);
  }

  /**
   * Writes the tail of the map to the stream.
   */
  public void writeMapEnd()
    throws IOException
  {
    os.write('z');
  }

  /**
   * Writes a remote object reference to the stream.  The type is the
   * type of the remote interface.
   *
   * <code><pre>
   * 'r' 't' b16 b8 type url
   * </pre></code>
   */
  public void writeRemote(String type, String url)
    throws IOException
  {
    os.write('r');
    os.write('t');
    printLenString(type);
    os.write('S');
    printLenString(url);
  }

  /**
   * Writes a boolean value to the stream.  The boolean will be written
   * with the following syntax:
   *
   * <code><pre>
   * T
   * F
   * </pre></code>
   *
   * @param value the boolean value to write.
   */
  public void writeBoolean(boolean value)
    throws IOException
  {
    if (value)
      os.write('T');
    else
      os.write('F');
  }

  /**
   * Writes an integer value to the stream.  The integer will be written
   * with the following syntax:
   *
   * <code><pre>
   * I b32 b24 b16 b8
   * </pre></code>
   *
   * @param value the integer value to write.
   */
  public void writeInt(int value)
    throws IOException
  {
    os.write('I');
    os.write(value >> 24);
    os.write(value >> 16);
    os.write(value >> 8);
    os.write(value);
  }

  /**
   * Writes a long value to the stream.  The long will be written
   * with the following syntax:
   *
   * <code><pre>
   * L b64 b56 b48 b40 b32 b24 b16 b8
   * </pre></code>
   *
   * @param value the long value to write.
   */
  public void writeLong(long value)
    throws IOException
  {
    os.write('L');
    os.write((byte) (value >> 56));
    os.write((byte) (value >> 48));
    os.write((byte) (value >> 40));
    os.write((byte) (value >> 32));
    os.write((byte) (value >> 24));
    os.write((byte) (value >> 16));
    os.write((byte) (value >> 8));
    os.write((byte) (value));
  }

  /**
   * Writes a double value to the stream.  The double will be written
   * with the following syntax:
   *
   * <code><pre>
   * D b64 b56 b48 b40 b32 b24 b16 b8
   * </pre></code>