org.olat.search.service.document.file.pdf.PdfBoxExtractor.java Source code

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Here is the source code for org.olat.search.service.document.file.pdf.PdfBoxExtractor.java

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/**
 * <a href="http://www.openolat.org">
 * OpenOLAT - Online Learning and Training</a><br>
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License"); <br>
 * you may not use this file except in compliance with the License.<br>
 * You may obtain a copy of the License at the
 * <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache homepage</a>
 * <p>
 * Unless required by applicable law or agreed to in writing,<br>
 * software distributed under the License is distributed on an "AS IS" BASIS, <br>
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. <br>
 * See the License for the specific language governing permissions and <br>
 * limitations under the License.
 * <p>
 * Initial code contributed and copyrighted by<br>
 * frentix GmbH, http://www.frentix.com
 * <p>
 */
package org.olat.search.service.document.file.pdf;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.util.PDFTextStripper;
import org.olat.core.logging.OLog;
import org.olat.core.logging.Tracing;
import org.olat.core.util.StringHelper;
import org.olat.core.util.io.LimitedContentWriter;
import org.olat.core.util.vfs.VFSLeaf;
import org.olat.search.service.document.file.DocumentAccessException;
import org.olat.search.service.document.file.FileContent;
import org.olat.search.service.document.file.FileDocumentFactory;

/**
 * 
 * Initial date: 19.07.2013<br>
 * @author srosse, stephane.rosse@frentix.com, http://www.frentix.com
 *
 */
public class PdfBoxExtractor implements PdfExtractor {

    private static final OLog log = Tracing.createLoggerFor(PdfBoxExtractor.class);

    @Override
    public void extract(VFSLeaf document, File bufferFile) throws IOException, DocumentAccessException {
        FileContent content = extractTextFromPdf(document);
        storePdfTextInBuffer(content, bufferFile);
    }

    private void storePdfTextInBuffer(FileContent pdfText, File pdfTextFile) throws IOException {
        try (FileWriter out = new FileWriter(pdfTextFile)) {
            if (StringHelper.containsNonWhitespace(pdfText.getTitle())) {
                out.write(pdfText.getTitle());
                out.write("\u00A0|\u00A0");
            }
            out.write(pdfText.getContent());
        } catch (IOException e) {
            throw e;
        }
    }

    private FileContent extractTextFromPdf(VFSLeaf leaf) throws IOException, DocumentAccessException {
        if (log.isDebug())
            log.debug("readContent from pdf starts...");
        PDDocument document = null;
        BufferedInputStream bis = null;
        try {
            bis = new BufferedInputStream(leaf.getInputStream());
            document = PDDocument.load(bis);
            if (document.isEncrypted()) {
                try {
                    document.decrypt("");
                } catch (Exception e) {
                    log.warn("PDF is encrypted. Can not read content file=" + leaf.getName());
                    LimitedContentWriter writer = new LimitedContentWriter(128,
                            FileDocumentFactory.getMaxFileSize());
                    writer.append(leaf.getName());
                    writer.close();
                    return new FileContent(leaf.getName(), writer.toString());
                }
            }
            String title = getTitle(document);
            if (log.isDebug())
                log.debug("readContent PDDocument loaded");
            PDFTextStripper stripper = new PDFTextStripper();
            LimitedContentWriter writer = new LimitedContentWriter(50000, FileDocumentFactory.getMaxFileSize());
            stripper.writeText(document, writer);
            writer.close();
            return new FileContent(title, writer.toString());
        } finally {
            if (document != null) {
                document.close();
            }
            if (bis != null) {
                bis.close();
            }
        }
    }

    private String getTitle(PDDocument document) {
        if (document != null && document.getDocumentInformation() != null) {
            return document.getDocumentInformation().getTitle();
        }
        return null;
    }
}