code: public void addDirectoryOperation(DirectoryOperation op, File f) {
  		addAll(op.getUpdatedFiles(), updatedFiles);
  		addAll(op.getNewFiles(), newFiles);
  		addAll(op.getUnchangedFiles(), unchangedFiles);
  		addAll(op.getDeletedFiles(), deletedFiles);
  
  		Object obj;
  		for (Enumeration e = op.failedTransfers.keys(); e.hasMoreElements();) {
  			obj = e.nextElement();
  			failedTransfers.put(obj, op.failedTransfers.get(obj));
  		}
  
  		recursedDirectories.addElement(f);
  	}
docs: Add the contents of another directory operation. This is used to record
  changes when recuring through directories.
  
  @param op
  @param f