/*
 * SAXSource.java
 * Copyright (C) 2004 The Free Software Foundation
 * 
 * This file is part of GNU JAXP, a library.
 *
 * GNU JAXP is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * GNU JAXP is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library.  Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obliged to do so.  If you do not wish to do so, delete this
 * exception statement from your version. 
 */

package javax.xml.transform.sax;

import java.io.InputStream;
import java.io.Reader;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;

/**
 * Specifies a SAX XML source. This is a tuple of input source and SAX
 * parser.
 *
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
public class SAXSource
  implements Source
{

  /**
   * Factory feature indicating that SAX sources are supported.
   */
  public static final String FEATURE =
    "http://javax.xml.transform.sax.SAXSource/feature";

  private XMLReader  xmlReader;
  private InputSource  inputSource;

  /**
   * Default constructor.
   */
  public SAXSource()
  {
  }

  /**
   * Constructor with a SAX parser and input source.
   */
  public SAXSource(XMLReader reader, InputSource inputSource)
  {
    xmlReader = reader;
    this.inputSource = inputSource;
  }

  /**
   * Constructor with an input source.
   * The SAX parser will be instantiated by the transformer.
   */
  public SAXSource(InputSource inputSource)
  {
    this.inputSource = inputSource;
  }

  /**
   * Sets the SAX parser to be used by this source.
   * If null, the transformer will instantiate its own parser.
   */
  public void setXMLReader(XMLReader reader)
  {
    xmlReader = reader;
  }

  /**
   * Returns the SAX parser to be used by this source.
   * If null, the transformer will instantiate its own parser.
   */
  public XMLReader getXMLReader()
  {
    return xmlReader;
  }

  /**
   * Sets the input source to parse.
   */
  public void setInputSource(InputSource inputSource)
  {
    this.inputSource = inputSource;
  }

  /**
   * Returns the input source to parse.
   */
  public InputSource getInputSource()
  {
    return inputSource;
  }

  /**
   * Sets the system ID for this source.
   */
  public void setSystemId(String systemId)
  {
    if (inputSource != null)
      {
        inputSource.setSystemId(systemId);
      }
  }

  /**
   * Returns the system ID for this source.
   */
  public String getSystemId()
  {
    if (inputSource != null)
      {
        return inputSource.getSystemId();
      }
    return null;
  }

  /**
   * Converts a source into a SAX input source.
   * This method can use a StreamSource or the system ID.
   * @return an input source or null
   */
  public static InputSource sourceToInputSource(Source source)
  {
    InputSource in = null;
    if (source instanceof SAXSource)
      {
        in = ((SAXSource) source).getInputSource();
      }
    else if (source instanceof StreamSource)
      {
        StreamSource streamSource = (StreamSource) source;
        InputStream inputStream = streamSource.getInputStream();
        if (inputStream != null)
          {
            in = new InputSource(inputStream);
          }
        else
          {
            Reader reader = streamSource.getReader();
            if (reader != null)
              {
                in = new InputSource(reader);
              }
          }
        String publicId = streamSource.getPublicId();
        if (publicId != null && in != null)
          {
            in.setPublicId(publicId);
          }
      }
    String systemId = source.getSystemId();
    if (systemId != null)
      {
        if (in == null)
          {
            in = new InputSource(systemId);
          }
        else
          {
            in.setSystemId(systemId);
          }
      }
    return in;
  }

}
