public void addPhoneNumberDescriptor() {
    XMLDescriptor descriptor = new XMLDescriptor();
    descriptor.setJavaClass(PhoneNumber.class);
    descriptor.setDefaultRootElement("phone-number");

    XMLDirectMapping num = new XMLDirectMapping();
    num.setAttributeName("number");
    num.setXPath("text()");
    descriptor.addMapping(num);

    this.addDescriptor(descriptor);
  }
  public XMLDescriptor addAddressDescriptor() {
    XMLDescriptor descriptor = new XMLDescriptor();
    descriptor.setJavaClass(Address.class);
    descriptor.setDefaultRootElement("address");

    XMLDirectMapping street = new XMLDirectMapping();
    street.setAttributeName("street");
    street.setXPath("street/text()");
    descriptor.addMapping(street);

    this.addDescriptor(descriptor);
    return descriptor;
  }