Runtime

Conformance

As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.

The key words MAY, MUST, MUST NOT, OPTIONAL, RECOMMENDED, REQUIRED, SHALL, SHALL NOT, SHOULD, and SHOULD NOT in this document are to be interpreted as described in [RFC2119] and [RFC8174] when, and only when, they appear in all capitals, as shown here.

1. Overview

This module defines the data model for recording actual user behavior as a causally ordered event chain. Ordering is established by explicit linkage between events, not by timestamps.

2. Terminology

• JourneyExecution: A bounded container for events belonging to one logical trace.

• RuntimeEvent: An atomic record of a single runtime moment.

• Event Chain: A sequence where each event references its immediate predecessor via previousId.

3. Event Chaining

graph LR
  subgraph Execution [JourneyExecution]
    direction LR
    E1[Event A, id: e1<br/>previousId: null]
    E2[Event B, id: e2<br/>previousId: e1]
    E3[Event C, id: e3<br/>previousId: e2]
    E1 -->|previousId| E2
    E2 -->|previousId| E3
  end

4. Chain Validity Rules

Within a single JourneyExecution:

1. Uniqueness: No two events MAY share the same id.

2. Root: Exactly one event MUST be the Root Event (previousId is null or empty string).

3. Resolution: Every non-root previousId MUST match the id of an event in the same events[].

4. Single Successor: An event id MUST NOT be referenced as previousId by more than one event. (No branching.)

5. Acyclic: The chain MUST NOT contain cycles.

If any rule above is violated, the JourneyExecution is invalid.

5. Reconstruction

A Consumer reconstructing event order MUST:

1. Identify the Root Event.

2. Repeatedly select the unique event whose previousId equals the current event’s id.

3. Continue until no successor exists.

Appendix: Combined JSON Example

{
  "type": "UJGDocument",
  "specVersion": "1.0",
  "items": [
    {
      "type": "JourneyExecution",
      "id": "urn:session:12345",
      "events": [
        {
          "type": "RuntimeEvent",
          "id": "evt-100",
          "previousId": null,
          "stateRef": "urn:ujg:state:product-page",
          "payload": { "action": "view" }
        },
        {
          "type": "RuntimeEvent",
          "id": "evt-200",
          "previousId": "evt-100",
          "stateRef": "urn:ujg:state:cart",
          "payload": { "item": "shoes" }
        }
      ]
    }
  ]
}

{
  "type": "UJGDocument",
  "specVersion": "1.0",
  "items": [
    {
      "type": "JourneyExecution",
      "id": "urn:session:12345",
      "events": [
        {
          "type": "RuntimeEvent",
          "id": "evt-100",
          "previousId": null,
          "stateRef": "urn:ujg:state:product-page",
          "payload": { "action": "view" }
        },
        {
          "type": "RuntimeEvent",
          "id": "evt-200",
          "previousId": "evt-100",
          "stateRef": "urn:ujg:state:cart",
          "payload": { "item": "shoes" }
        }
      ]
    }
  ]
}

References