package de.unigoettingen.sub.commons.ocr.util.merge;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import com.lowagie.text.Document;
import com.lowagie.text.DocumentException;
import com.lowagie.text.pdf.PdfCopy;
import com.lowagie.text.pdf.PdfImportedPage;
import com.lowagie.text.pdf.PdfReader;
import com.lowagie.text.pdf.SimpleBookmark;
public class PdfMerger extends Merger {
@Override
@SuppressWarnings("unchecked")
public void merge(List<InputStream> inputs, OutputStream output) {
try {
// Stolen from itext (com.lowagie.tools.concat_pdf)
int pageOffset = 0;
List<HashMap<String, Object>> master = new ArrayList<HashMap<String, Object>>();
int f = 0;
Document document = null;
PdfCopy writer = null;
while (f < inputs.size()) {
// we create a reader for a certain document
PdfReader reader = new PdfReader(inputs.get(f));
reader.consolidateNamedDestinations();
// we retrieve the total number of pages
int n = reader.getNumberOfPages();
List<HashMap<String, Object>> bookmarks = SimpleBookmark
.getBookmark(reader);
if (bookmarks != null) {
if (pageOffset != 0) {
SimpleBookmark
.shiftPageNumbers(bookmarks, pageOffset, null);
}
master.addAll(bookmarks);
}
pageOffset += n;
if (f == 0) {
// step 1: creation of a document-object
document = new Document(reader.getPageSizeWithRotation(1));
// step 2: we create a writer that listens to the document
writer = new PdfCopy(document, output);
// step 3: we open the document
document.open();
}
// step 4: we add content
PdfImportedPage page;
for (int i = 0; i < n;) {
++i;
page = writer.getImportedPage(reader, i);
writer.addPage(page);
}
writer.freeReader(reader);
f++;
}
if (!master.isEmpty()) {
writer.setOutlines(master);
}
// step 5: we close the document
document.close();
} catch (IOException e) {
throw new IllegalStateException("Error while merging files.", e);
} catch (DocumentException e) {
throw new IllegalStateException("Error while merging files.", e);
}
}
}