====== 12.8 Establish or Update FX Contract State ======

[[fxdemo:04-part:12-phase-0-interaction-pattern-realization:start | Go To Phase 0 Interaction Pattern Realization ]]

The Establish or Update FX Contract State pattern realizes Phase 0 contract state determination.

The implementation participant performing the Contract State Management Role consumes validation and semantic interpretation outputs, applies the selected Phase 0 contract-state logic, produces FX Contract State, and publishes it to the contract state DDS Topic.

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**Table 12-6:** Establish or Update FX Contract State implementation realization.
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^ Realization Concern ^ Phase 0 Implementation Treatment ^
| FX logical interaction pattern | Establish or Update FX Contract State |
| Primary implementation participant | Contract state implementation participant |
| Primary Runtime Plane | FX Logical Data Plane |
| Supporting Runtime Plane | FX Logical Audit and Provenance Plane |
| Input DDS Topics | Data.FX.ValidationResult; Data.FX.SemanticAssertion; transaction-related Topics as required by Phase 0 |
| Output DDS Topic | Data.FX.ContractState |
| Primary IDL / generated types | FxValidationResult; FxSemanticAssertion; FxContractState |
| Expected processing outcome | Implementation publishes applicable FX Contract State, along with prior state, target state, transition context, producing participant, and timestamp, where Phase 0 requires it. |
| Logging and exception handling | Missing input, unsupported transition, transition failure, publication failure, and retry conditions follow the logging and exception-handling baseline. |
| Audit and provenance expectation | Contract state records preserve input references, transition rule context, producing participant, timestamp, and state outcome. |
| Traceability expectation | Interaction traces to FX Contract State Node, Contract State Management Role, FX Contract State Endpoint, FX Contract State, and implementation participant. |

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