code: public Map getPdfLayers() {
      	if (documentOCG.isEmpty()) {
      		readOCProperties();
      	}
      	HashMap map = new HashMap();
      	PdfLayer layer;
      	String key;
      	for (Iterator i = documentOCG.iterator(); i.hasNext(); ) {
      		layer = (PdfLayer)i.next();
      		if (layer.getTitle() == null) {
      			key = layer.getAsString(PdfName.NAME).toString();
      		}
      		else {
      			key = layer.getTitle();
      		}
      		if (map.containsKey(key)) {
      			int seq = 2;
      			String tmp = key + "(" + seq + ")";
      			while (map.containsKey(tmp)) {
      				seq++;
      				tmp = key + "(" + seq + ")";
      			}
      			key = tmp;
      		}
  			map.put(key, layer);
      	}
      	return map;
      }
docs: Gets the PdfLayer objects in an existing document as a Map
  with the names/titles of the layers as keys.
  @return	a Map with all the PdfLayers in the document (and the name/title of the layer as key)
  @since	2.1.2