/*
 * DSS - Digital Signature Services
 *
 * Copyright (C) 2013 European Commission, Directorate-General Internal Market and Services (DG MARKT), B-1049 Bruxelles/Brussel
 *
 * Developed by: 2013 ARHS Developments S.A. (rue Nicolas Bové 2B, L-1253 Luxembourg) http://www.arhs-developments.com
 *
 * This file is part of the "DSS - Digital Signature Services" project.
 *
 * "DSS - Digital Signature Services" is free software: you can redistribute it and/or modify it under the terms of
 * the GNU Lesser General Public License as published by the Free Software Foundation, either version 2.1 of the
 * License, or (at your option) any later version.
 *
 * DSS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with
 * "DSS - Digital Signature Services".  If not, see <http://www.gnu.org/licenses/>.
 */

package eu.europa.ec.markt.dss.signature.pdf;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import eu.europa.ec.markt.dss.signature.pdf.pdfbox.PdfBoxObjectFactory;

/**
 * The usage of this interface permit the user to choose the underlying PDF library use to created PDF signatures.
 * 
 * 
 * @version $Revision: 1653 $ - $Date: 2013-02-01 11:48:52 +0100 (Fri, 01 Feb 2013) $
 */
public abstract class PdfObjFactory {

   private static final org.slf4j.Logger LOGGER = org.slf4j.LoggerFactory.getLogger(PdfObjFactory.class.getName());

   private static PdfObjFactory INSTANCE;

   public static PdfObjFactory getInstance() {
      if (INSTANCE == null) {
         String factoryClassName = System.getProperty("dss.pdf_obj_factory");
         if (factoryClassName != null) {
            LOGGER.info("Using '" + factoryClassName + "' as the PDF Object Factory Implementation");
            try {
               @SuppressWarnings("unchecked")
               Class<PdfObjFactory> factoryClass = (Class<PdfObjFactory>) Class.forName(factoryClassName);
               INSTANCE = factoryClass.newInstance();
            } catch (Exception ex) {
               LOGGER.error("dss.pdf_obj_factory is '" + factoryClassName + "' but factory cannot be instantiated (fallback will be used)");
            }
         }
         if (INSTANCE == null) {
            LOGGER.info("Fallback to '" + PdfBoxObjectFactory.class.getName() + "' as the PDF Object Factory Implementation");
            INSTANCE = new PdfBoxObjectFactory();
         }
      }
      return INSTANCE;
   }

   public abstract PdfArray newArray();

   public abstract PdfDict newDict(String dictType);

   public PdfDict newDict() {
      return newDict(null);
   }

   public abstract PdfReader newReader(InputStream input) throws IOException;

   public abstract PdfStream newStream(byte[] bytes) throws IOException;

   public abstract PdfWriter newWriter(PdfReader reader, OutputStream output) throws IOException;

   public abstract PDFSignatureService newPAdESSignatureService();

   public abstract PDFTimestampService newTimestampSignatureService();

}