private Optional<ValidationEvent> validateTrait(Shape shape, XmlNamespaceTrait xmlNamespace) {
        // Validate the xmlNamespace URI against the URI specification.
        try {
            new java.net.URI(xmlNamespace.getUri());
        } catch (java.net.URISyntaxException uriSyntaxException) {
            return Optional.of(error(shape,
                    format(
                            "An `xmlNamespace` trait is applied to the %s shape with an invalid uri: %s",
                            shape,
                            xmlNamespace.getUri())));
        }

        return Optional.empty();
    }
Validates that the xmlNamespace traits are applied correctly for structures.

<ul>
    <li>Validates that uri is valid.</li>
</ul>
smithy-model/src/main/java/software/amazon/smithy/model/validation/validators/XmlNamespaceTraitValidator.java