PPTX2TextConverter.java

/*
 * (C) Copyright 2006-2012 Nuxeo SA (http://nuxeo.com/) and others.
 *
 * 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.
 *
 * Contributors:
 *     Nuxeo
 *     Antoine Taillefer
 *
 */

package org.nuxeo.ecm.core.convert.plugins.text.extractors;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.nuxeo.ecm.core.convert.plugins.text.extractors.presentation.PresentationSlide;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;

/**
 * Pptx to text converter: parses the Open XML presentation document to read its content.
 */
public class PPTX2TextConverter extends XmlZip2TextConverter {

    protected static final Log log = LogFactory.getLog(PPTX2TextConverter.class);

    private static final String PRESENTATION_SLIDE_ZIP_ENTRY_NAME_PREFIX = "ppt/slides/slide";

    protected void readXmlZipContent(ZipInputStream zis, XMLReader reader, StringBuilder sb) throws IOException,
            SAXException {

        Set<PresentationSlide> slides = new TreeSet<PresentationSlide>();

        ZipEntry zipEntry = zis.getNextEntry();
        while (zipEntry != null) {
            String zipEntryName = zipEntry.getName();
            if (zipEntryName.startsWith(PRESENTATION_SLIDE_ZIP_ENTRY_NAME_PREFIX)
                    && zipEntryName.length() > PRESENTATION_SLIDE_ZIP_ENTRY_NAME_PREFIX.length()) {
                char slideNumberChar = zipEntryName.charAt(PRESENTATION_SLIDE_ZIP_ENTRY_NAME_PREFIX.length());
                int slideNumber = -1;
                try {
                    slideNumber = Integer.parseInt(String.valueOf(slideNumberChar));
                } catch (NumberFormatException nfe) {
                    log.warn("Slide number is not an non integer, won't take this slide into account.");
                }
                if (slideNumber > -1) {
                    OpenXmlContentHandler contentHandler = new OpenXmlContentHandler();
                    reader.setContentHandler(contentHandler);
                    reader.parse(new InputSource(new ByteArrayInputStream(IOUtils.toByteArray(zis))));
                    slides.add(new PresentationSlide(contentHandler.getContent(), slideNumber));
                }
            }
            zipEntry = zis.getNextEntry();
        }
        if (!slides.isEmpty()) {
            Iterator<PresentationSlide> slidesIt = slides.iterator();
            while (slidesIt.hasNext()) {
                PresentationSlide slide = slidesIt.next();
                sb.append(slide.getContent());
                sb.append("\n");
            }
        }
    }
}