contrib/textfilters/src/java/org/apache/jackrabbit/core/query/PdfTextFilter.java

/*
 * Copyright 2004-2005 The Apache Software Foundation or its licensors,
 *                     as applicable.
 *
 * 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.jackrabbit.core.query;

import java.io.CharArrayReader;
import java.io.CharArrayWriter;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import javax.jcr.RepositoryException;

import org.apache.jackrabbit.core.query.lucene.FieldNames;
import org.apache.jackrabbit.core.state.PropertyState;
import org.apache.jackrabbit.core.value.BLOBFileValue;
import org.apache.jackrabbit.core.value.InternalValue;
import org.pdfbox.pdfparser.PDFParser;
import org.pdfbox.pdmodel.PDDocument;
import org.pdfbox.util.PDFTextStripper;

/**
 * Extracts texts from Adobe PDF document binary data.
 * Taken from Jakarta Slide class
 * <code>org.apache.slide.extractor.PDFExtractor</code>
 */
public class PdfTextFilter implements TextFilter {

    /**
     * @return <code>true</code> for <code>application/pdf</code>, <code>false</code> otherwise.
     */
    public boolean canFilter(String mimeType) {
        return "application/pdf".equalsIgnoreCase(mimeType);
    }

    /**
     * Returns a map with a single entry for field {@link FieldNames#FULLTEXT}.
     * @param data object containing Adobe PDF document data.
     * @param encoding text encoding is not used, since it is specified in the data.
     * @return a map with a single Reader value for field {@link FieldNames#FULLTEXT}.
     * @throws RepositoryException if data is a multi-value property or it does not
     * contain valid PDF document.
     */
    public Map doFilter(PropertyState data, String encoding) throws RepositoryException {
        InternalValue[] values = data.getValues();
        if (values.length > 0) {
            BLOBFileValue blob = (BLOBFileValue) values[0].internalValue();
                
            try {
                PDFParser parser = new PDFParser(blob.getStream());
                parser.parse();
    
                PDDocument document = parser.getPDDocument();
    
                CharArrayWriter writer = new CharArrayWriter();
    
                PDFTextStripper stripper = new PDFTextStripper();
                stripper.setLineSeparator("\n");
                stripper.writeText(document, writer);
    
                document.close();
                writer.close();
                
                Map result = new HashMap();
                result.put(FieldNames.FULLTEXT, new CharArrayReader(writer.toCharArray()));
                return result;
            } 
            catch (IOException ex) {
                throw new RepositoryException(ex);
            }
        } 
        else {
            // multi value not supported
            throw new RepositoryException("Multi-valued binary properties not supported.");
        }
    }
}