int (@NotNull ProblemDescriptorKey o) { if (file == null || o.file == null) { return Boolean.compare(file == null, o.file == null); } int comparison = file.getPath().compareTo(o.file.getPath()); if (comparison == 0) comparison = Integer.compare(lineNumber, o.lineNumber); if (comparison == 0) comparison = Integer.compare(position, o.position); if (comparison == 0) comparison = descriptionTemplate.compareTo(o.descriptionTemplate); return comparison; }