protected Writer writer;

        /** The mapping item being updated, or null for read-only operations. */
        protected CharMappingItem item;

        /**
         * Constructs a new MappingUpdater for handling file updates.
         *
         * @param newItem the character mapping item to update, or null for read-only operations
         */
        protected MappingUpdater(final CharMappingItem newItem) {