src/org/apache/xalan/transformer/SerializerSwitcher.java

/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * 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 acknowledgment:  
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written 
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * 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 THE APACHE SOFTWARE FOUNDATION 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.xalan.transformer;

import java.io.Writer;
import java.io.OutputStream;

import java.util.Properties;

import org.apache.xalan.templates.StylesheetRoot;

import org.xml.sax.ContentHandler;

import javax.xml.transform.TransformerException;
import javax.xml.transform.OutputKeys;

import org.apache.xalan.serialize.Serializer;
import org.apache.xalan.serialize.SerializerFactory;
import org.apache.xalan.serialize.Method;
import org.apache.xalan.templates.OutputProperties;

/**
 * This is a helper class that decides if Xalan needs to switch
 * serializers, based on the first output element.
 */
public class SerializerSwitcher
{

  /**
   * Switch to HTML serializer if element is HTML
   *
   *
   * @param transformer Non-null transformer instance
   * @param ns Namespace URI of the element
   * @param localName Local part of name of element
   *
   * @throws TransformerException
   */
  public static void switchSerializerIfHTML(
          TransformerImpl transformer, String ns, String localName)
            throws TransformerException
  {

    if (null == transformer)
      return;

    if (((null == ns) || (ns.length() == 0))
            && localName.equalsIgnoreCase("html"))
    {
      // System.out.println("transformer.getOutputPropertyNoDefault(OutputKeys.METHOD): "+
      //              transformer.getOutputPropertyNoDefault(OutputKeys.METHOD));     
      // Access at level of hashtable to see if the method has been set.
      if (null != transformer.getOutputPropertyNoDefault(OutputKeys.METHOD))
        return;

      // Getting the output properties this way won't cause a clone of 
      // the properties.
      Properties prevProperties = transformer.getOutputFormat().getProperties();
      
      // We have to make sure we get an output properties with the proper 
      // defaults for the HTML method.  The easiest way to do this is to 
      // have the OutputProperties class do it.
      OutputProperties htmlOutputProperties = new OutputProperties(Method.HTML);

      htmlOutputProperties.copyFrom(prevProperties, true);
      Properties htmlProperties = htmlOutputProperties.getProperties();

      try
      {
        Serializer oldSerializer = transformer.getSerializer();

        if (null != oldSerializer)
        {
          Serializer serializer =
            SerializerFactory.getSerializer(htmlProperties);

          Writer writer = oldSerializer.getWriter();

          if (null != writer)
            serializer.setWriter(writer);
          else
          {
            OutputStream os = oldSerializer.getOutputStream();

            if (null != os)
              serializer.setOutputStream(os);
          }

          transformer.setSerializer(serializer);

          ContentHandler ch = serializer.asContentHandler();

          transformer.setContentHandler(ch);
        }
      }
      catch (java.io.IOException e)
      {
        throw new TransformerException(e);
      }
    }
  }
  
  /**
   * Get the value of a property, without using the default properties.  This 
   * can be used to test if a property has been explicitly set by the stylesheet 
   * or user.
   *
   * @param name The property name, which is a fully-qualified URI.
   *
   * @return The value of the property, or null if not found.
   *
   * @throws IllegalArgumentException If the property is not supported, 
   * and is not namespaced.
   */
  private static String getOutputPropertyNoDefault(String qnameString, Properties props)
    throws IllegalArgumentException
  {    
    String value = (String)props.get(qnameString);
    
    return value;
  }
  
  /**
   * Switch to HTML serializer if element is HTML
   *
   *
   * @param ns Namespace URI of the element
   * @param localName Local part of name of element
   *
   * @throws TransformerException
   * @return new contentHandler.
   */
  public static Serializer switchSerializerIfHTML(
          String ns, String localName, Properties props, Serializer oldSerializer)
            throws TransformerException
  {
    Serializer newSerializer = oldSerializer;

    if (((null == ns) || (ns.length() == 0))
            && localName.equalsIgnoreCase("html"))
    {
      // System.out.println("transformer.getOutputPropertyNoDefault(OutputKeys.METHOD): "+
      //              transformer.getOutputPropertyNoDefault(OutputKeys.METHOD));     
      // Access at level of hashtable to see if the method has been set.
      if (null != getOutputPropertyNoDefault(OutputKeys.METHOD, props))
        return newSerializer;

      // Getting the output properties this way won't cause a clone of 
      // the properties.
      Properties prevProperties = props;
      
      // We have to make sure we get an output properties with the proper 
      // defaults for the HTML method.  The easiest way to do this is to 
      // have the OutputProperties class do it.
      OutputProperties htmlOutputProperties = new OutputProperties(Method.HTML);

      htmlOutputProperties.copyFrom(prevProperties, true);
      Properties htmlProperties = htmlOutputProperties.getProperties();

//      try
      {
        if (null != oldSerializer)
        {
          Serializer serializer =
            SerializerFactory.getSerializer(htmlProperties);

          Writer writer = oldSerializer.getWriter();

          if (null != writer)
            serializer.setWriter(writer);
          else
          {
            OutputStream os = serializer.getOutputStream();

            if (null != os)
              serializer.setOutputStream(os);
          }
          newSerializer = serializer;
        }
      }
//      catch (java.io.IOException e)
//      {
//        throw new TransformerException(e);
//      }
    }
    return newSerializer;
  }
  
}