EnvelopeCodec

Reads and writes Envelopes as the JSON value of a Kafka message, with Wow's mapper (WowJson): every number of a payload or a state keeps its exact value and scale, and the modules are fixed, so the wire form does not depend on what a host brings.

• Value: {"format":1,"kind":"state-event","id":…,"type":…,"payload":{…},"transport":{…}}; transport is null when there is none, and holds the wait context and the trace only, in the one form of a transport (me.ahoo.wow.spi.log.TransportCodec): the reservations of a log entry stay in the context.

• Reading: unknown fields are ignored at every level, so this version reads what the next minor one writes; a format other than Envelope.FORMAT, or a kind this version does not know, is refused with an IllegalArgumentException.

• State events: stateEvent and stateEventOf turn a StateEventRecord into the envelope of kind EnvelopeKind.STATE_EVENT and back: id is ref@version, type the aggregate type, payload {ref, version, commandId, requestId, commandType, commitTime, events, state, scope, deleted, access, accessVersion, causation, headers, operator, imported} (operator, imported, access and accessVersion, additions within format 1; imported only when true; access in its stored form, AccessValues, or null when not stamped, and an envelope of a version that wrote tags instead reads with none; accessVersion the version it is of, null with it or when an envelope of an earlier version left it out) with each event {name, revision, payload} and the state {version, schemaFingerprint, state} or null.