* @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);

    /**

    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

     */
    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(

     */
    public int getLineNumber() {
        return lineNumber;
    }

    /**
     * Gets the one-based index of the column containing the error.
     *
     * @return The one-based index of the column containing the error or non-positive value if unknown.
     */
    public int getColumnNumber() {
        return columnNumber;
    }

            source = getSource();
        }

        if (line <= 0 && column <= 0 && exception instanceof ModelParserException e) {
            line = e.getLineNumber();
            column = e.getColumnNumber();
        }

        ModelProblem problem =
                new DefaultModelProblem(message, severity, version, source, line, column, modelId, exception);

        add(problem);
    }

            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);

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

    /**
     * Creates a string with all location details for the specified model problem. If the project identifier is
     * provided, the generated location will omit the model id and source information and only give line/column
     * information for problems originating directly from this POM.
     *
     * @param problem The problem whose location should be formatted, must not be {@code null}.