Migrate process design to typed standard kernels

The typed workflow is additive. Existing mechanical-design classes continue to work, but new or migrated code should make editions, applicability, readiness, calculation status, cases, and qualification evidence explicit.

Backward compatibility

The migration preserves the existing public source entry points. Legacy standard factories, single-argument canonical-unit methods, mechanical-design execution methods, and unconfigured DesignOptimizer fluent calls remain available. The strict selection and typed-kernel APIs are additive and can be adopted incrementally.

Backward compatibility does not mean identical behavior. Correctness fixes deliberately change several observable results:

• DesignOptimizer.optimize() without explicit search bounds reports VALIDATED or AUTO_SIZED with isConverged() == false; it no longer claims that an optimization ran.
• invalid safety factors, null objectives, incompatible shared design updates, unsupported strict selections, and incomplete typed-kernel inputs fail earlier;
• system mechanical-design execution retains caller-configured design objects instead of replacing them with defaults;
• the API 610 catalog default is the implemented 13th-edition screening basis, and API 521/API 526 applicability is restricted to relief-system equipment;
• returned equipment-size collections are defensive snapshots and no longer expose mutable internal state.

Existing integrations should therefore continue to compile, but tests or control logic that relied on the previous permissive outcomes must migrate to explicit result statuses. This compatibility contract covers public source APIs and normal runtime use; deserializing Java object graphs written by older NeqSim versions is outside its scope.

1. Replace global edition overrides

Process-global overrides are deprecated because concurrent projects can observe each other’s mutable state. Carry the edition and amendments with the design instead:

// Legacy compatibility only
StandardRegistry.setVersionOverride(StandardType.API_610, "13th Ed");

// Reproducible project selection
StandardEdition edition = StandardEdition.of(StandardType.API_610, "13th Ed",
    Collections.singletonList("Project amendment A"));
StandardSelection selection = StandardSelection.strict(edition);

StandardSelection.legacy(...) is a temporary compatibility bridge. It preserves permissive factory behavior and must not be interpreted as calculation support.

2. Separate metadata factories from executable calculations

StandardRegistry.createStandard(...) creates the legacy category-specific metadata/calculation object. It does not prove that the selected edition has an executable implementation. Require the typed kernel when a calculation is needed:

EquipmentDesignKernel<?, ?> kernel = StandardRegistry.requireDesignKernel(selection);

The call fails with KERNEL_NOT_IMPLEMENTED or EDITION_NOT_IMPLEMENTED instead of returning a metadata object that appears usable. The concrete kernel then checks equipment applicability and input readiness before calculation.

3. Snapshot mutable calculator inputs

API 610 and API 617 adapters accept configured legacy calculators for compatibility, but their input constructors snapshot the scalar configuration. Configure first, construct the typed input, and do not reuse a calculated legacy object as uncontrolled evidence. API 521 similarly copies the protected item basis. Returned assessments and collections are immutable snapshots.

Every caller must branch on EngineeringCalculationResult.Status. A CALCULATED_REVIEW_REQUIRED result contains findings; it is not certification. BLOCKED retains structured readiness findings, and FAILED identifies an execution failure.

4. Migrate design cases and envelopes

The envelope-only DesignCaseEngine.run(...) entry point is deprecated. Build one deterministic EngineeringCaseSet and use EngineeringCaseRunner:

EngineeringCaseRunReport report = EngineeringCaseRunner.run(process, caseSet,
    EngineeringCaseRunOptions.builder()
        .failurePolicy(EngineeringCaseFailurePolicy.THROW_WITH_PARTIAL_RESULT)
        .build());

Use report.isComplete() before treating the envelope as a closed basis. isAccepted() additionally requires acceptance limits for every governing metric and no violations. An exception thrown under THROW_WITH_PARTIAL_RESULT retains the report for diagnosis and audit.

For an EngineeringProject, use EngineeringSimulationRunner.buildCaseSet(project) so the detailed runner, closed design loop, and deliverable compiler use the same case identity and ordering.

5. Run regression and qualification gates

StandardDesignKernelVerificationSuite.evaluateRegression() executes the five registered kernels, numeric API baselines, API 526 SI/customary equivalence, and API 12J metre/micrometre equivalence. Require areAllBenchmarksPassed() in regression CI. Do not use that flag as qualification: isPassed() requires independently reviewed, non-regression evidence for every exact method@version.

Recommended deployment order

1. Inventory legacy standards and record explicit editions and amendments.
2. Introduce strict selections and resolve catalog-only, edition, and applicability failures.
3. Move calculation calls behind typed kernels without deleting the legacy configuration path.
4. Replace envelope-only execution and require complete case reports.
5. Add project limits, independent benchmark datasets, applicability envelopes, and approvals.
6. Remove use of global overrides only after integrations have migrated and the removal is scheduled for a major release.

The complete runnable API 526 path is in examples/neqsim/process/design/StandardDesignKernelMigrationExample.java.