* @param line The one-based index of the line containing the problem or {@code -1} if unknown.
     * @param column The one-based index of the column containing the problem or {@code -1} if unknown.
     * @param cause The cause of the problem, may be {@code null}.
     */
    void add(Problem.Severity severity, String message, int line, int column, Exception cause);

    /**

     */
    int getLineNumber();

    /**
     * Gets the one-based index of the column containing the problem. The column number should refer to some text file
     * that is given by {@link #getSource()}.
     *
     * @return the one-based index of the column containing the problem or non-positive value if unknown
     */
    int getColumnNumber();

    /**

    public void setSource(String source) {
        this.source = source;
    }

    @Override
    public void add(Problem.Severity severity, String message, int line, int column, Exception cause) {
        Problem problem = new DefaultProblem(message, severity, source, line, column, cause);

        problems.add(problem);
    }

     * returns -1 if none is available.
     * @return the current line number
     */
    int getLineNumber();

    /**
     * Return the column number where the current event ends,
     * returns -1 if none is available.
     * @return the current column number
     */
    int getColumnNumber();

    /**
     * Return the byte or character offset into the input source this location

                                problem.getLineNumber() > 0 ? "line " + problem.getLineNumber() : "",
                                problem.getColumnNumber() > 0 ? "column " + problem.getColumnNumber() : "")
                        .filter(s -> !s.isEmpty())
                        .collect(Collectors.joining(", "));
                if (!loc.isEmpty()) {

    private static class SimpleProblemCollector implements SettingsProblemCollector {

        public List<String> messages = new ArrayList<>();

        public void add(Severity severity, String message, int line, int column, Exception cause) {
            messages.add(message);
        }
    }

     */

     */
    int getLineNumber();

    /**
     * Gets the one-based index of the column containing the problem. The column number should refer to some text file
     * that is given by {@link #getSource()}.
     *
     * @return The one-based index of the column containing the problem or non-positive value if unknown.
     */
    int getColumnNumber();

    /**

     * @param lineNumber The one-based index of the line containing the problem or {@code -1} if unknown.
     * @param columnNumber The one-based index of the column containing the problem or {@code -1} if unknown.
     * @param exception The exception that caused this problem, may be {@code null}.
     */
    DefaultProblem(

                .appendText(formatLocation(columnNumber, lineNumber));
    }

    private String formatLocation(int columnNumber, int lineNumber) {
        return String.format("line %d, column %d", lineNumber, columnNumber);
    }

    @Override
    public void describeMismatch(final Object o, final Description description) {
        if (!(o instanceof ProjectBuildingResult)) {

            buffer.append("line ").append(getLineNumber());
        }
        if (getColumnNumber() > 0) {
            if (!buffer.isEmpty()) {
                buffer.append(", ");
            }
            buffer.append("column ").append(getColumnNumber());
        }
        return buffer.toString();
    }

    @Override
    public String toString() {
        StringBuilder buffer = new StringBuilder(128);