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UJG / Editor's Draft /
W3C Community Group Draft Report

Runtime

draft

Status of this Document

This report was published by the User Journal Graph Community Group . It is not a W3C Standard nor is it on the W3C Standards Track. Please note that under the W3C Community Contributor License Agreement (CLA) there is a limited opt-out and other conditions apply. Learn more about W3C Community and Business Groups .

Last Update
2026-01-28
Editors
  • Seva Dolgopolov
Group
User Journal Graph Community Group
Repository
View Source
License
W3C-Software-and-Document

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

3.1. Visual Model

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

3.2. The JourneyExecution Object (The Container)

A JourneyExecution MUST include:

  • type: "JourneyExecution"

  • id: required, MUST be a valid URI/URN, unique within resolution scope.

  • eventRefs: array of RuntimeEvent IDs

3.3. The RuntimeEvent Object (The Atom)

A RuntimeEvent MUST include:

  • type: "RuntimeEvent"

  • id: required, MUST be a valid URI/URN, unique within resolution scope.

  • executionId: ID of the owning JourneyExecution

  • previousId: string or null

    • null indicates the Root Event

    • otherwise MUST equal the id of another event in the same JourneyExecution

  • stateRef: string (Graph State or CompositeState id)

A RuntimeEvent MAY include:

  • payload: object (domain-specific data)

4. Chain Validity Rules

Within a single execution (events where executionId equals the JourneyExecution id):

  1. Root: Exactly one event MUST be the Root Event.

  2. Resolution: Every non-root previousId MUST match the id of an event in the same execution.

  3. Single Successor: An event id MUST NOT be referenced as previousId by more than one event in the same execution.

  4. 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

json 
{
  "@context": "https://ujg.specs.openuji.org/ed/context.jsonld",
  "type": "UJGDocument",
  "specVersion": "1.0",
   "items": [
    {
      "type": "JourneyExecution",
      "id": "urn:ujg:execution:12345",
      "eventRefs": [
        "urn:ujg:event:12345:100",
        "urn:ujg:event:12345:200"
      ]
    },
    {
      "type": "RuntimeEvent",
      "id": "urn:ujg:event:12345:100",
      "executionId": "urn:ujg:execution:12345",
      "previousId": null,
      "stateRef": "urn:ujg:state:product-page",
      "payload": { "action": "view" }
    },
    {
      "type": "RuntimeEvent",
      "id": "urn:ujg:event:12345:200",
      "executionId": "urn:ujg:execution:12345",
      "previousId": "urn:ujg:event:12345:100",
      "stateRef": "urn:ujg:state:cart",
      "payload": { "item": "shoes" }
    }
  ]
}
{
  "@context": "https://ujg.specs.openuji.org/ed/context.jsonld",
  "type": "UJGDocument",
  "specVersion": "1.0",
   "items": [
    {
      "type": "JourneyExecution",
      "id": "urn:ujg:execution:12345",
      "eventRefs": [
        "urn:ujg:event:12345:100",
        "urn:ujg:event:12345:200"
      ]
    },
    {
      "type": "RuntimeEvent",
      "id": "urn:ujg:event:12345:100",
      "executionId": "urn:ujg:execution:12345",
      "previousId": null,
      "stateRef": "urn:ujg:state:product-page",
      "payload": { "action": "view" }
    },
    {
      "type": "RuntimeEvent",
      "id": "urn:ujg:event:12345:200",
      "executionId": "urn:ujg:execution:12345",
      "previousId": "urn:ujg:event:12345:100",
      "stateRef": "urn:ujg:state:cart",
      "payload": { "item": "shoes" }
    }
  ]
}

References

Normative References