Rearchitect use cases into a Bukkit-free flow layer with request/response types

[nbdSteve]

Summary

Moves every use case in the plugin into a flow layer, so the decisions live in plain Java and Bukkit only appears at the edges.

Before this, the equip/unequip listeners, the /ap command tree and the GUI purchase action each mixed three concerns: reading state out of Bukkit and NBT, deciding what should happen, and applying the result back to the server. That made the decisions untestable without a running server and left the same rules duplicated across handlers.

Control flow is now strictly one direction:

Bukkit event or command -> adapter (listener/, command/)
  -> converter builds the flow's Request (reads Bukkit, NBT, config)
    -> flow decides, returns a Response of plain data
      -> adapter applies the Response back to Bukkit

Adapters carry no decisions and flows touch no platform.

What changed

Nine use-case flows, grouped by concept, each with its own request/response pair:

Flow	Use case
flow.set.ArmorPieceEquipFlow	equipping a piece: which slot's apply commands run, where a replaced head item goes
flow.set.ArmorPieceUnequipFlow	unequipping a piece
flow.set.ArmorSetCommandFlow	/<set-name> ... routing
flow.player.PlayerSetSessionFlow	join/quit set tracking
flow.combat.ArmorCombatRoutingFlow	worn set vs held item vs neither
flow.command.ArmorPlusCommandFlow	/ap subcommand resolution
flow.command.ArmorCommandAccessFlow	sender kind, then permission
flow.command.ArmorSetGiveFlow	give validation
flow.purchase.ArmorPiecePurchaseFlow	GUI purchase affordability

Adapters. listener/ holds the Bukkit event adapters and the new command/ package holds the command adapters (ArmorPlusCommand as the /ap TabExecutor, plus ArmorGuiCommand, ArmorHelpCommand, ArmorReloadCommand, ArmorSetGiveCommand, and ArmorCommandAccessGate as the shared permission adapter). This replaces the old cmd/ + cmd/sub/ packages. converter/ translates between Bukkit objects and the flow request/response types.

ArmorSwitchListener is deliberately left alone: it only republishes ArmorEquipEvents for the equip/unequip listeners, so it holds no use case of its own.

Damage and tracking logic moved into service.set.ArmorPieceSlotResolver and the existing pure registries, so the adapters no longer own it.

Enforcement

• ArchUnit LayeringRulesTest now rejects any dependency from flow.. on org.bukkit.., net.minecraft.. or de.tr7zw.., alongside the existing model.. and service.. rules. The layering is mechanically checked, not just documented.
• All nine flows and the two pure converters are on the JaCoCo check-core list at 100% line and branch coverage. The build fails if that drops.
• 380 tests pass; mvn -B clean verify is green on JDK 25.

Behavior preservation

This is a refactor, not a behavior change. The characterization suite under src/test/java/gg/steve/mc/ap/{data,player,armor,message} pins the existing behavior and is unchanged apart from one constructor-arity line - no assertion was modified.

Two rounds of review on this branch caught real regressions in the first draft, each fixed here:

• Command ordering. An intermediate version computed set-completeness before dispatching the per-slot commands.apply/commands.remove. That inverted what an ArmorPlus PAPI placeholder inside those commands observed, and stopped an apply command that changes worn armor from influencing the completeness verdict. The original ordering is restored: slot commands dispatch first, then a second flow call (completeSet, with its own ArmorSetCompletionRequest/Response) does the scan and the single registry write. ArmorEquipOrderingTest pins the dispatch order with Mockito InOrder so it cannot silently regress again.
• Fail-open permission gate. ArmorCommandAccessGate defaulted to allowing an unrecognized sender or permission. It now denies.
• Eager converter work. Converters were reading the head-items config list and running Set.isWearingSet's four-slot NBT scan before the flow's cheap guards could discard the request. They now short-circuit on the same facts the flow's IGNORED guard reads. Same fix applied to the purchase converter's unconditional permission read, the give converter resolving target and permission before the arity check, and the attacker converter resolving a damager on already-cancelled events.

Notes for the reviewer

• Flows are bound in ArmorPlusModule through @Provides @Singleton factory methods rather than @Inject on the classes, specifically so the service and flow layers import zero DI types.
• No outbound-port adapter is built yet; flows still hand platform work back to their calling adapter. The model.port interfaces remain the declared boundary for a later change.
• Emitted bytecode stays Java 8 as before; only the test sources target 17.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud