VersionInfo info = infos.get(key);
        if (info == null) {
            info = new VersionInfo(timestamp, version, repository);
            infos.put(key, info);
        } else if (info.isOutdated(timestamp)) {
            info.version = version;
            info.repository = repository;
            info.timestamp = timestamp;
        }
    }

     * @return true if updated, false otherwise
     */
    public boolean isUpdated() {
        return newInput != null;
    }

    /**
     * Checks if this item has been deleted.
     * @return true if deleted, false otherwise
     */
    public boolean isDeleted() {
        return isUpdated() && newInput.length() == 0;
    }

    @Override
    public int hashCode() {

     */
    public boolean isUpdated() {
        return newInput != null && newOutput != null;
    }

    /**
     * Checks if the item has been marked for deletion.
     *
     * @return true if the item is marked for deletion, false otherwise.
     */
    public boolean isDeleted() {
        return isUpdated() && StringUtil.isBlank(newInput);
    }

    @Override

    }

    /**
     * Checks whether this mapping item has pending updates.
     *
     * @return true if both newInputs and newOutput are not null, indicating pending updates
     */
    public boolean isUpdated() {
        return newInputs != null && newOutput != null;
    }

    /**
     * Checks whether this mapping item is marked for deletion.

     */
    public boolean isUpdated() {
        return newInput != null;
    }

    /**
     * Checks if the item has been marked for deletion.
     *
     * @return true if the item is marked for deletion, false otherwise.
     */
    public boolean isDeleted() {
        return isUpdated() && newInput.length() == 0;
    }

    @Override

     *
     * @return True if the item has been updated.
     */
    public boolean isUpdated() {
        return newToken != null;
    }

    /**
     * Returns true if the item has been deleted.
     *
     * @return True if the item has been deleted.
     */
    public boolean isDeleted() {
        return isUpdated() && newToken.length() == 0;
    }

    @Override
    public int hashCode() {

     */
    public boolean isUpdated() {
        return newInputs != null && newOutputs != null;
    }

    /**
     * Checks if the item has been marked for deletion.
     *
     * @return true if the item is marked for deletion, false otherwise.
     */
    public boolean isDeleted() {
        return isUpdated() && newInputs.length == 0;
    }

    @Override

         */
        public KuromojiItem write(final KuromojiItem oldItem) {
            try {
                if (item == null || item.getId() != oldItem.getId() || !item.isUpdated()) {
                    writer.write(oldItem.toLineString());
                    writer.write(Constants.LINE_SEPARATOR);
                    return oldItem;
                }

         */
        public CharMappingItem write(final CharMappingItem oldItem) {
            try {
                if (item == null || item.getId() != oldItem.getId() || !item.isUpdated()) {
                    writer.write(oldItem.toLineString());
                    writer.write(Constants.LINE_SEPARATOR);
                    return oldItem;
                }

         */
        public SynonymItem write(final SynonymItem oldItem) {
            try {
                if (item == null || item.getId() != oldItem.getId() || !item.isUpdated()) {
                    writer.write(oldItem.toLineString());
                    writer.write(Constants.LINE_SEPARATOR);
                    return oldItem;
                }