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

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

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

    }

    /**
     * Converts the item to a string representation for writing to a file.
     *
     * @return A string in the format "input=>output".
     */
    public String toLineString() {
        if (isUpdated()) {
            return newInput + "=>" + newOutput;
        }
        return input + "=>" + output;
    }

    }

    /**
     * Converts the item to a string representation for writing to a file.
     *
     * @return The stopword as a string.
     */
    public String toLineString() {
        if (isUpdated()) {
            return StringUtils.join(newInput);
        }
        return StringUtils.join(input);
    }

     * If the item has pending updates, the new values are used; otherwise, the current values are used.
     *
     * @return compact string representation of the mapping rule
     */
    public String toLineString() {
        if (isUpdated()) {
            return StringUtils.join(newInputs, ",") + "=>" + newOutput;
        }
        return StringUtils.join(inputs, ",") + "=>" + output;
    }

    }

    /**
     * Converts the item to a string representation for writing to a file.
     *
     * @return A string in the format "input1,input2=>output1,output2".
     */
    public String toLineString() {
        if (isUpdated()) {
            if (Arrays.equals(newInputs, newOutputs)) {
                return StringUtils.join(newInputs, ",");
            }

    }

    /**
     * Returns the item as a line string.
     *
     * @return The item as a line string.
     */
    public String toLineString() {
        final StringBuilder buf = new StringBuilder(100);
        if (isUpdated()) {
            buf.append(quoteEscape(newToken));
            buf.append(',');

        // Debug: print what we actually got
        if (result.size() > 0) {
            for (CharMappingItem item : result) {
                System.out.println("Unexpected item: " + item.toLineString());
            }
        }

        // An empty file should return no items
        assertEquals("Empty file should have no items", 0, result.size());