5 Universally Unique Identifier (UUID)

Within the context of any Energistics specification, a UUID as defined by RFC 4122 (https://tools.ietf.org/html/rfc4122 ) identifies a unique data object. The UUID may or may not be generated or ‘owned’ by a server, so long as it conforms to the standard for a UUID. A UUID is more precisely an array of 16 unsigned bytes (or a single 128 bit unsigned integer), and can be printed and serialized in various ways. When serialized, Energistics specifications always expect the UUID to appear in ‘Microsoft Registry Format’, which looks like this:

f81d4fae-7dec-11d0-a765-00a0c91e6bf6

A UUID can also be represented as a special form of URI (as described below).

urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6

A UUID by itself should only be used where the underlying data object types are known, are described in metadata, or can be discovered using some kind of service.