Model model = loadPom(session, request, result);
        if (model != null) {
            Map<String, Object> config = session.getConfigProperties();
            ArtifactDescriptorReaderDelegate delegate =
                    (ArtifactDescriptorReaderDelegate) config.get(ArtifactDescriptorReaderDelegate.class.getName());

            if (delegate == null) {
                delegate = this.delegate;

            PlexusConfiguration config = configuration.getChild(parameter.getName(), false);
            if (config != null) {
                String expression = config.getValue(null);

                try {
                    value = expressionEvaluator.evaluate(expression);

                    if (value == null) {
                        value = config.getAttribute("default-value", null);
                    }