public static void registerClipboardFormat(ClipboardFormat format) { checkNotNull(format); for (String key : format.getAliases()) { String lowKey = key.toLowerCase(Locale.ENGLISH); ClipboardFormat old = aliasMap.put(lowKey, format); if (old != null) { aliasMap.put(lowKey, old); WorldEdit.logger.warning(format.getClass().getName() + " cannot override existing alias '" + lowKey + "' used by " + old.getClass().getName()); } } for (String ext : format.getFileExtensions()) { String lowExt = ext.toLowerCase(Locale.ENGLISH); fileExtensionMap.put(lowExt, format); } registeredFormats.add(format); }