/**
     * Get the identifier of the POM in the format {@code
     * <groupId>:<artifactId>:<version>}.
     *
     * @return String
     */
    public String getModelId() {
        return this.modelId;
    } // -- String getModelId()

    /**
     * Set the path/URL of the POM or {@code null} if unknown.
     *
     * @param location
     */
    public void setLocation(String location) {

        return this.location;
    }

    /**
     * Get the identifier of the POM in the format {@code <groupId>:<artifactId>:<version>}.
     *
     * @return the model id
     */
    public String getModelId() {
        return this.modelId;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {

        }
        try {
            InputSource source = null;
            if (request.getModelId() != null || request.getLocation() != null) {
                source = new InputSource(request.getModelId(), request.getLocation());
            }
            MavenToolchainsStaxReader xml = new MavenToolchainsStaxReader();

            if (req.getLocation().getSource() != null) {
                modelId = req.getLocation().getSource().getModelId();
                source = req.getLocation().getSource().getLocation();
            }
        }

        if (modelId == null) {
            modelId = getModelId();
            source = getSource();
        }

    @Nullable
    InputStream getInputStream();

    @Nullable
    Reader getReader();

    @Nullable
    Transformer getTransformer();

    boolean isStrict();

    @Nullable
    String getModelId();

    @Nullable
    String getLocation();

    boolean isAddDefaultEntities();

    interface Transformer {
        /**
         * Interpolate the value read from the xml document
         *

     */
    public static String formatLocation(ModelProblem problem, String projectId) {
        StringBuilder buffer = new StringBuilder(256);

        if (!problem.getModelId().equals(projectId)) {
            buffer.append(problem.getModelId());
            if (!problem.getSource().isEmpty()) {
                if (!buffer.isEmpty()) {
                    buffer.append(", ");
                }

                sb.append("] ");
                sb.append(problem.getMessage());
                String loc = Stream.of(
                                problem.getModelId().equals(modelId) ? problem.getModelId() : "",
                                problem.getModelId().equals(modelId) ? problem.getSource() : "",
                                problem.getLineNumber() > 0 ? "line " + problem.getLineNumber() : "",

            if (location.getSource() != null) {
                modelId = location.getSource().getModelId();
                source = location.getSource().getLocation();
            }
        }

        if (modelId == null) {
            modelId = getModelId();
            source = getSource();
        }

        }
        try {
            InputSource source = null;
            if (request.getModelId() != null || request.getLocation() != null) {
                source = new InputSource(
                        request.getModelId(), path != null ? path.toUri().toString() : null);
            }
            MavenStaxReader xml = new MavenStaxReader();

     */
    public static String formatLocation(ModelProblem problem, String projectId) {
        StringBuilder buffer = new StringBuilder(256);

        if (!problem.getModelId().equals(projectId)) {
            buffer.append(problem.getModelId());

            if (!problem.getSource().isEmpty()) {
                if (buffer.length() > 0) {
                    buffer.append(", ");
                }