Java tutorial
/** * The contents of this file are subject to the license and copyright * detailed in the LICENSE and NOTICE files at the root of the source * tree and available online at * * http://www.dspace.org/license/ */ package org.dspace.content.packager; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.sql.SQLException; import java.util.Calendar; import java.util.List; import org.apache.commons.lang.ArrayUtils; import org.apache.log4j.Logger; import org.apache.pdfbox.cos.COSDocument; import org.apache.pdfbox.pdfparser.PDFParser; import org.apache.pdfbox.pdmodel.PDDocument; import org.apache.pdfbox.pdmodel.PDDocumentInformation; import org.dspace.authorize.AuthorizeException; import org.dspace.content.Bitstream; import org.dspace.content.BitstreamFormat; import org.dspace.content.Bundle; import org.dspace.content.Collection; import org.dspace.content.DCDate; import org.dspace.content.DSpaceObject; import org.dspace.content.Item; import org.dspace.content.WorkspaceItem; import org.dspace.content.crosswalk.CrosswalkException; import org.dspace.content.crosswalk.MetadataValidationException; import org.dspace.core.Constants; import org.dspace.core.Context; import org.dspace.core.LogManager; import org.dspace.core.SelfNamedPlugin; import org.dspace.core.Utils; /** * Accept a PDF file by itself as a SIP. * <p> * This is mainly a proof-of-concept to demonstrate the flexibility * of the packager and crosswalk plugins. * <p> * To import, open up the PDF and try to extract sufficient metadata * from its InfoDict. * <p> * Export is a crude hack: if the item has a bitstream containing PDF, * send that, otherwise it fails. Do not attempt to insert metadata. * * @author Larry Stone * @version $Revision$ * @see PackageIngester * @see PackageDisseminator */ public class PDFPackager extends SelfNamedPlugin implements PackageIngester, PackageDisseminator { /** log4j category */ private static final Logger log = Logger.getLogger(PDFPackager.class); private static final String BITSTREAM_FORMAT_NAME = "Adobe PDF"; private static String aliases[] = { "PDF", "Adobe PDF", "pdf", "application/pdf" }; public static String[] getPluginNames() { return (String[]) ArrayUtils.clone(aliases); } // utility to grovel bitstream formats.. private static void setFormatToMIMEType(Context context, Bitstream bs, String mimeType) throws SQLException { BitstreamFormat bf[] = BitstreamFormat.findNonInternal(context); for (int i = 0; i < bf.length; ++i) { if (bf[i].getMIMEType().equalsIgnoreCase(mimeType)) { bs.setFormat(bf[i]); break; } } } /** * Create new Item out of the ingested package, in the indicated * collection. It creates a workspace item, which the application * can then install if it chooses to bypass Workflow. * <p> * This is a VERY crude import of a single Adobe PDF (Portable * Document Format) file, using the document's embedded metadata * for package metadata. If the PDF file hasn't got the minimal * metadata available, it is rejected. * <p> * @param context DSpace context. * @param parent collection under which to create new item. * @param pkgFile The package file to ingest * @param params package parameters (none recognized) * @param license may be null, which takes default license. * @return workspace item created by ingest. * @throws PackageException if package is unacceptable or there is * a fatal error turning it into an Item. */ public DSpaceObject ingest(Context context, DSpaceObject parent, File pkgFile, PackageParameters params, String license) throws PackageValidationException, CrosswalkException, AuthorizeException, SQLException, IOException { boolean success = false; Bundle original = null; Bitstream bs = null; WorkspaceItem wi = null; try { // Save the PDF in a bitstream first, since the parser // has to read it as well, and we cannot "rewind" it after that. wi = WorkspaceItem.create(context, (Collection) parent, false); Item myitem = wi.getItem(); original = myitem.createBundle("ORIGINAL"); InputStream fileStream = null; try { fileStream = new FileInputStream(pkgFile); bs = original.createBitstream(fileStream); } finally { if (fileStream != null) { fileStream.close(); } } bs.setName("package.pdf"); setFormatToMIMEType(context, bs, "application/pdf"); bs.update(); if (log.isDebugEnabled()) { log.debug("Created bitstream ID=" + String.valueOf(bs.getID()) + ", parsing..."); } crosswalkPDF(context, myitem, bs.retrieve()); wi.update(); context.commit(); success = true; log.info(LogManager.getHeader(context, "ingest", "Created new Item, db ID=" + String.valueOf(myitem.getID()) + ", WorkspaceItem ID=" + String.valueOf(wi.getID()))); myitem = PackageUtils.finishCreateItem(context, wi, null, params); return myitem; } finally { // get rid of bitstream and item if ingest fails if (!success) { if (original != null && bs != null) { original.removeBitstream(bs); } if (wi != null) { wi.deleteAll(); } } context.commit(); } } /** * IngestAll() cannot be implemented for a PDF ingester, because there's only one PDF to ingest */ public List<String> ingestAll(Context context, DSpaceObject parent, File pkgFile, PackageParameters params, String license) throws PackageException, UnsupportedOperationException, CrosswalkException, AuthorizeException, SQLException, IOException { throw new UnsupportedOperationException( "PDF packager does not support the ingestAll() operation at this time."); } /** * Replace is not implemented. */ public DSpaceObject replace(Context context, DSpaceObject dso, File pkgFile, PackageParameters params) throws PackageException, UnsupportedOperationException, CrosswalkException, AuthorizeException, SQLException, IOException { throw new UnsupportedOperationException( "PDF packager does not support the replace() operation at this time."); } /** * ReplaceAll() cannot be implemented for a PDF ingester, because there's only one PDF to ingest */ public List<String> replaceAll(Context context, DSpaceObject dso, File pkgFile, PackageParameters params) throws PackageException, UnsupportedOperationException, CrosswalkException, AuthorizeException, SQLException, IOException { throw new UnsupportedOperationException( "PDF packager does not support the replaceAll() operation at this time."); } /** * VERY crude dissemination: just look for the first * bitstream with the PDF package type, and toss it out. * Works on packages importer with this packager, and maybe some others. */ public void disseminate(Context context, DSpaceObject dso, PackageParameters params, File pkgFile) throws PackageValidationException, CrosswalkException, AuthorizeException, SQLException, IOException { if (dso.getType() != Constants.ITEM) { throw new PackageValidationException("This disseminator can only handle objects of type ITEM."); } Item item = (Item) dso; BitstreamFormat pdff = BitstreamFormat.findByShortDescription(context, BITSTREAM_FORMAT_NAME); if (pdff == null) { throw new PackageValidationException("Cannot find BitstreamFormat \"" + BITSTREAM_FORMAT_NAME + "\""); } Bitstream pkgBs = PackageUtils.getBitstreamByFormat(item, pdff, Constants.DEFAULT_BUNDLE_NAME); if (pkgBs == null) { throw new PackageValidationException( "Cannot find Bitstream with format \"" + BITSTREAM_FORMAT_NAME + "\""); } //Make sure our package file exists if (!pkgFile.exists()) { PackageUtils.createFile(pkgFile); } //open up output stream to copy bitstream to file FileOutputStream out = null; try { //open up output stream to copy bitstream to file out = new FileOutputStream(pkgFile); Utils.copy(pkgBs.retrieve(), out); } finally { if (out != null) { out.close(); } } } /** * disseminateAll() cannot be implemented for a PDF disseminator, because there's only one PDF to disseminate */ public List<File> disseminateAll(Context context, DSpaceObject dso, PackageParameters params, File pkgFile) throws PackageException, CrosswalkException, AuthorizeException, SQLException, IOException { throw new UnsupportedOperationException( "PDF packager does not support the disseminateAll() operation at this time."); } /** * Identifies the MIME-type of this package, i.e. "application/pdf". * * @return the MIME type (content-type header) of the package to be returned */ public String getMIMEType(PackageParameters params) { return "application/pdf"; } private void crosswalkPDF(Context context, Item item, InputStream metadata) throws CrosswalkException, IOException, SQLException, AuthorizeException { COSDocument cos = null; try { PDFParser parser = new PDFParser(metadata); parser.parse(); cos = parser.getDocument(); // sanity check: PDFBox breaks on encrypted documents, so give up. if (cos.getEncryptionDictionary() != null) { throw new MetadataValidationException("This packager cannot accept an encrypted PDF document."); } /* PDF to DC "crosswalk": * * NOTE: This is not in a crosswalk plugin because (a) it isn't * useful anywhere else, and more importantly, (b) the source * data is not XML so it doesn't fit the plugin's interface. * * pattern of crosswalk -- PDF dict entries to DC: * Title -> title.null * Author -> contributor.author * CreationDate -> date.created * ModDate -> date.created * Creator -> description.provenance (application that created orig) * Producer -> description.provenance (convertor to pdf) * Subject -> description.abstract * Keywords -> subject.other * date is java.util.Calendar */ PDDocument pd = new PDDocument(cos); PDDocumentInformation docinfo = pd.getDocumentInformation(); String title = docinfo.getTitle(); // sanity check: item must have a title. if (title == null) { throw new MetadataValidationException( "This PDF file is unacceptable, it does not have a value for \"Title\" in its Info dictionary."); } if (log.isDebugEnabled()) { log.debug("PDF Info dict title=\"" + title + "\""); } item.addDC("title", null, "en", title); String value = docinfo.getAuthor(); if (value != null) { item.addDC("contributor", "author", null, value); if (log.isDebugEnabled()) { log.debug("PDF Info dict author=\"" + value + "\""); } } value = docinfo.getCreator(); if (value != null) { item.addDC("description", "provenance", "en", "Application that created the original document: " + value); } value = docinfo.getProducer(); if (value != null) { item.addDC("description", "provenance", "en", "Original document converted to PDF by: " + value); } value = docinfo.getSubject(); if (value != null) { item.addDC("description", "abstract", null, value); } value = docinfo.getKeywords(); if (value != null) { item.addDC("subject", "other", null, value); } // Take either CreationDate or ModDate as "date.created", // Too bad there's no place to put "last modified" in the DC. Calendar calValue = docinfo.getCreationDate(); if (calValue == null) { calValue = docinfo.getModificationDate(); } if (calValue != null) { item.addDC("date", "created", null, (new DCDate(calValue.getTime())).toString()); } item.update(); } finally { if (cos != null) { cos.close(); } } } /** * Returns a user help string which should describe the * additional valid command-line options that this packager * implementation will accept when using the <code>-o</code> or * <code>--option</code> flags with the Packager script. * * @return a string describing additional command-line options available * with this packager */ @Override public String getParameterHelp() { return "No additional options available."; } }