net.sourceforge.vaticanfetcher.model.parse.PdfParser.java Source code

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Here is the source code for net.sourceforge.vaticanfetcher.model.parse.PdfParser.java

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/*******************************************************************************
 * Copyright (c) 2011 Tran Nam Quang.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Tran Nam Quang - initial API and implementation
 *******************************************************************************/

package net.sourceforge.vaticanfetcher.model.parse;

import java.io.IOException;
import java.io.InputStream;
import java.io.StringWriter;
import java.util.Collection;
import java.util.Collections;

import net.sourceforge.vaticanfetcher.enums.Msg;
import net.sourceforge.vaticanfetcher.util.annotations.NotNull;
import net.sourceforge.vaticanfetcher.util.annotations.Nullable;

import org.apache.pdfbox.exceptions.CryptographyException;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentInformation;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.util.PDFTextStripper;

public final class PdfParser extends StreamParser {

    private static final Collection<String> extensions = Collections.singleton("pdf");
    private static final Collection<String> types = MediaType.Col.application("pdf");

    PdfParser() {
    }

    @Override
    protected ParseResult parse(@NotNull InputStream in, @NotNull final ParseContext context)
            throws ParseException {
        PDDocument pdfDoc = null;
        try {
            /* TODO post-release-1.1: check if 'force' argument in PDDocument/Stripper increases number of parsed PDF files */
            pdfDoc = PDDocument.load(in, true);
            PDDocumentInformation pdInfo;
            final int pageCount;
            try {
                pdInfo = pdfDoc.getDocumentInformation();
                pageCount = pdfDoc.getNumberOfPages();
            } catch (ClassCastException e) {
                // Bug #3529070 and #3528345
                throw new ParseException(e);
            }
            StringWriter writer = new StringWriter();

            /*
             * If the PDF file is encrypted, the PDF stripper will automatically try an empty password.
             * 
             * In contrast to the paging PDF parser that is used for the preview, we do not need to call 
             * setSortByPosition(true) here because the extracted text will be digested by Lucene anyway.
             */
            PDFTextStripper stripper = new PDFTextStripper() {
                protected void startPage(PDPage page) throws IOException {
                    context.getReporter().subInfo(getCurrentPageNo(), pageCount);
                }

                protected void endPage(PDPage page) throws IOException {
                    if (context.getCancelable().isCanceled())
                        setEndPage(0);
                }
            };
            stripper.setForceParsing(true);

            try {
                stripper.writeText(pdfDoc, writer);
            } catch (RuntimeException e) {
                /* PDFTextStripper.writeText can throw various RuntimeExceptions, see bugs #3446010, #3448272, #3444887. */
                throw new ParseException(e);
            }

            return new ParseResult(writer.getBuffer()).setTitle(pdInfo.getTitle()).addAuthor(pdInfo.getAuthor())
                    .addMiscMetadata(pdInfo.getSubject()).addMiscMetadata(pdInfo.getKeywords());
        } catch (IOException e) {
            if (e.getCause() instanceof CryptographyException)
                throw new ParseException(Msg.doc_pw_protected.get());
            throw new ParseException(e);
        } finally {
            close(pdfDoc);
        }
    }

    static void close(@Nullable PDDocument doc) {
        if (doc != null) {
            try {
                doc.close();
            } catch (IOException e) {
            }
        }
    }

    protected Collection<String> getExtensions() {
        return extensions;
    }

    protected Collection<String> getTypes() {
        return types;
    }

    public String getTypeLabel() {
        return Msg.filetype_pdf.get();
    }

}