final Model model,
            final Path projectDir,
            final ModelBuildingRequest config,
            ModelProblemCollector problems) {
        Map<String, String> modelProperties = model.getProperties();

        ValueSource projectPrefixValueSource;
        ValueSource prefixlessObjectBasedValueSource;
        if (config.getValidationLevel() >= ModelBuildingRequest.VALIDATION_LEVEL_MAVEN_4_0) {

            final Model model, final File projectDir, final ProjectBuilderConfiguration config) {
        String timestampFormat = DEFAULT_BUILD_TIMESTAMP_FORMAT;

        Properties modelProperties = model.getProperties();
        if (modelProperties != null) {
            timestampFormat = modelProperties.getProperty(BUILD_TIMESTAMP_FORMAT_PROPERTY, timestampFormat);
        }