String (@NotNull String semicolonDelimited) { StringTokenizer tokenizer = new StringTokenizer(semicolonDelimited, FileTypeConsumer.EXTENSION_DELIMITER, false); StringBuilder builder = null; while (tokenizer.hasMoreTokens()) { String extension = tokenizer.nextToken().trim(); if (myPendingAssociations.findByExtension(extension) == null && getFileTypeByExtension(extension) == UnknownFileType.INSTANCE) { if (builder == null) { builder = new StringBuilder(); } else if (builder.length() > 0) { builder.append(FileTypeConsumer.EXTENSION_DELIMITER); } builder.append(extension); } } return builder == null ? "" : builder.toString(); }