ASF_20_SRC_AUTO/src/blocks/poi/java/org/apache/cocoon/serialization/POIFSSerializer.java

/*
 * Copyright 1999-2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.cocoon.serialization;

import java.io.IOException;
import java.io.OutputStream;

import org.apache.cocoon.components.elementprocessor.ElementProcessor;
import org.apache.cocoon.components.elementprocessor.impl.poi.POIFSElementProcessor;

import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import org.xml.sax.SAXException;

/**
 *  An extension of ElementProcessorSerializer with extensions for dealing with
 *  the POIFS filesystem This is an abstract class. Concrete extensions need to
 *  implement the following methods:
 *  <ul>
 *    <li> String getMimeType()</li>
 *    <li> void doLocalPreEndDocument()</li>
 *    <li> void doLocalPostEndDocument()</li>
 *    <li> ElementProcessorFactory getElementProcessorFactory()</li>
 *    </li>
 *  </ul>
 *
 * @author   Marc Johnson (marc_johnson27591@hotmail.com)
 * @author   Nicola Ken Barozzi (nicolaken@apache.org)
 * @version CVS $Id: POIFSSerializer.java,v 1.4 2004/03/05 13:02:07 bdelacretaz Exp $
 */
public abstract class POIFSSerializer extends ElementProcessorSerializer
{
  private POIFSFileSystem _filesystem;

  /**
   *  Constructor
   */

  public POIFSSerializer() {
    super();
    _filesystem = new POIFSFileSystem();
  }

  /*
   *  ********** START implementation of ContentHandler **********
   */
  /**
   *  Receive notification of the end of a document.
   *
   *@exception  SAXException  if there is an error writing the document to the
   *      output stream
   */

  public void endDocument() throws SAXException {
    doLocalPreEndDocument();

    OutputStream stream = getOutputStream();

    if ( stream != null ) {
      try {
        _filesystem.writeFilesystem( stream );
      } catch ( IOException e ) {
        throw SAXExceptionFactory(
          "could not process endDocument event", e );
      }
    } else {
      throw SAXExceptionFactory(
        "no outputstream for writing the document!!" );
    }
    doLocalPostEndDocument();
  }

  /**
   *  Provide access to the filesystem for extending classes
   *
   *@return    the filesystem
   */

  protected POIFSFileSystem getFilesystem() {
    return _filesystem;
  }

  /**
   *  Extending classes should do whatever they need to do prior to writing the
   *  filesystem out
   */

  protected abstract void doLocalPreEndDocument();

  /**
   *  Extending classes should do whatever they need to do after writing the
   *  filesystem out
   */

  protected abstract void doLocalPostEndDocument();

  /**
   *  perform pre-initialization on an element processor
   *
   *@param  processor         the element processor to be iniitialized
   *@exception  SAXException  on errors
   */

  protected void doPreInitialization(ElementProcessor processor)
      throws SAXException {
    try {
      ((POIFSElementProcessor)processor).setFilesystem(_filesystem);
    } catch (ClassCastException e) {
      throw SAXExceptionFactory( "could not pre-initialize processor", e );
    }
  }

  /*
   *  **********  END  implementation of ContentHandler **********
   */
}
// end public abstract class POIFSSerializer