public Attribute setNamespace(Namespace namespace) {
    if (namespace == null) {
      namespace = Namespace.NO_NAMESPACE;
    }

    // Verify the attribute isn't trying to be in a default namespace
    // Attributes can't be in a default namespace
    if (namespace != Namespace.NO_NAMESPACE &&
        "".equals(namespace.getPrefix())) {
      throw new IllegalNameException("", "attribute namespace",
                                     "An attribute namespace without a prefix can only be the " +
                                     "NO_NAMESPACE namespace");
    }
    this.namespace = namespace;
    specified = true;
    return this;
  }
public Attribute setNamespace(Namespace namespace)