PPTExtractor.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.nutch.parse.mspowerpoint;

// JDK imports
import java.io.IOException;
import java.io.InputStream;

// Nutch imports
import org.apache.nutch.parse.ms.MSExtractor;

// Jakarta POI imports
import org.apache.poi.poifs.eventfilesystem.POIFSReader;


/**
 * Converts the Powerpoint document content to plain text.
 * 
 * @author Stephan Strittmatter - http://www.sybit.de
 * @author Jérôme Charron
 */
class PPTExtractor extends MSExtractor {

  private StringBuffer text = null;
  private POIFSReader reader = null;
  
  
  protected String extractText(InputStream input) throws Exception {
    this.reader = new POIFSReader();
    this.text = new StringBuffer();
    reader.registerListener(
            new ContentReaderListener(this.text),
            PPTConstants.POWERPOINT_DOCUMENT);
    input.reset();
    if (input.available() > 0) {
      this.reader.read(input);
    } else if (LOG.isWarnEnabled()) {
      LOG.warn("Input <=0 :" + input.available());
    }
    return (this.text != null) ? text.toString() : null;
  }

}