@Override
  protected AbstractKerberosDescriptor getDescriptor(Type type, String name) {
    if (Type.IDENTITY == type) {
      return getIdentity(name);
    } else if (Type.CONFIGURATION == type) {
      return getConfiguration(name);
    } else {
      return null;
    }
  }
Gets the requested AbstractKerberosDescriptor implementation using a type name and a relevant
descriptor name.
<p/>
This implementation handles identity and configuration descriptors within this
AbstractKerberosDescriptorContainer.
<p/>
Implementing classes should override this to handle other types, but call this method to
ensure no data is missed.

@param type a String indicating the type of the requested descriptor
@param name a String indicating the name of the requested descriptor
@return a AbstractKerberosDescriptor representing the requested descriptor or null if not found
ambari-server/src/main/java/org/apache/ambari/server/state/kerberos/AbstractKerberosDescriptorContainer.java