pdffilter.java

dspace 用j2ee架构的一个数字图书馆.开源程序

/*
 * PDFFilter.java
 *
 * Version: $Revision: 1.8 $
 *
 * Date: $Date: 2005/07/29 15:56:07 $
 *
 * Copyright (c) 2002-2005, Hewlett-Packard Company and Massachusetts
 * Institute of Technology.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - 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.
 *
 * - Neither the name of the Hewlett-Packard Company nor the name of the
 * Massachusetts Institute of Technology nor the names of their
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS 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 COPYRIGHT
 * HOLDERS OR 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.
 */
package org.dspace.app.mediafilter;

import java.io.ByteArrayInputStream;
import java.io.InputStream;

import org.pdfbox.cos.COSDocument;
import org.pdfbox.pdfparser.PDFParser;
import org.pdfbox.pdmodel.PDDocument;
import org.pdfbox.util.PDFTextStripper;

/*
 * 
 * to do: helpful error messages - can't find mediafilter.cfg - can't
 * instantiate filter - bitstream format doesn't exist
 *  
 */
public class PDFFilter extends MediaFilter
{
    public String getFilteredName(String oldFilename)
    {
        return oldFilename + ".txt";
    }

    /**
     * @return String bundle name
     *  
     */
    public String getBundleName()
    {
        return "TEXT";
    }

    /**
     * @return String bitstreamformat
     */
    public String getFormatString()
    {
        return "Text";
    }

    /**
     * @return String description
     */
    public String getDescription()
    {
        return "Extracted text";
    }

    /**
     * @param source
     *            source input stream
     * 
     * @return InputStream the resulting input stream
     */
    public InputStream getDestinationStream(InputStream source)
            throws Exception
    {
        // get input stream from bitstream
        // pass to filter, get string back
        PDFTextStripper pts = new PDFTextStripper();
        PDFParser parser = new PDFParser(source);

        parser.parse();

        COSDocument cos = parser.getDocument();

        String extractedText = pts
                .getText(new PDDocument(parser.getDocument()));

        // now close the pdf
        cos.close();

        // if verbose flag is set, print out extracted text
        // to STDOUT
        if (MediaFilterManager.isVerbose)
        {
            System.out.println(extractedText);
        }

        // generate an input stream with the extracted text
        byte[] textBytes = extractedText.getBytes();
        ByteArrayInputStream bais = new ByteArrayInputStream(textBytes);

        return bais; // will this work? or will the byte array be out of scope?
    }
}