1.1.55

Rebranding & Configuration

• Package rename — io.github.hyshmily.hotkey → io.github.hyshmily.zeta, all class names and imports updated accordingly.
• Configuration prefix — hotkey.* → zeta.* (including local, sync, worker, report, spring‑cache, etc.).
• Artifact IDs — hotkey-parent → zeta-parent, hotkey → zeta, hotkey-worker → zeta-worker.
• Exchange/queue names — Default exchange names (zeta.report.exchange, zeta.heartbeat.exchange), queue prefixes, and Redis key prefixes all switched to zeta:*.

Architecture & Core Refactoring

• Interface/Impl split — Most concrete classes (e.g., SingleFlight, CircuitBreaker, ExpireManager, RingManager, HealthView, SreRateLimiter, VersionController, SystemLoadMonitor) are now public interfaces with package‑private implementation classes in impl/ sub‑packages.
• CentralDispatcher — Replaces scattered direct calls to CacheSyncPublisher and HotKeyReporter; provides unified recordAccess() and send() coordination.
• CacheCompressor abstraction — Value‑level LZ4 compression/decompression via Lz4CacheCompressor (falls back to no‑op if LZ4 unavailable).
• Memory‑weighted eviction — New CacheConfig with max‑weight (bytes) and DefaultWeigher to enforce memory‑based limits (overrides entry‑count when set).
• @Internal marker — Annotates classes not intended for public API consumption.

New Capabilities

• Atomic computeIfAbsent — Uses Caffeine's compute() within stripe lock, eliminating TOCTOU race between lookup and load.
• CAS operations — compareAndSet() and compareAndInvalidate() for lock‑free optimistic updates.
• Batch get — get(Iterable<String>, Function, ...) for bulk read‑through with per‑key TTL/report control.
• Timed refresh scheduler — registerRefresh(), updateRefresh(), unregisterRefresh() with a lazy 2‑thread pool for background periodic refresh.
• Per‑key ordered dispatcher — PerKeyOrderedDispatcher ensures FIFO execution of tasks for the same key in both CacheSyncListener and WorkerListener.
• Concurrent‑threads interception — New InterceptTrigger.CONCURRENT_THREADS with concurrentThreads() attribute to guard per‑key thread count.
• Broadcast control — All invalidate(), putThrough(), invalidateAfterPut() methods now accept an isBroadcastByThisTime parameter; invalidate(keys, false) replaces evictLocal().
• Multi‑key mutate‑invalidate — Batch invalidateAfterPut(Map) overload for atomic invalidations.

Fixes & Improvements

• Worker broadcast rollback — WorkerBroadcaster.broadcastHot/Cool() returns boolean; ReportConsumer calls rollbackToPreviousState() when broadcast fails, preventing state drift.
• INVALIDATE vs REFRESH race — CacheSyncListener tracks recentInvalidated high‑water mark per key, skipping stale REFRESH after an INVALIDATE.
• Stale‑return on circuit‑breaker open — HotKeyCache.mapEmpty() now returns the stale CacheEntry (if available) when circuit‑breaker is open, instead of Optional.empty().
• ExpireManager centralization — All CacheEntry construction flows through ExpireManager.createBuilder(), applyTtl(), replaceEntryValue(), unifying TTL logic and compression.

Dependency & Build Changes

• New dependencies — org.lz4:lz4‑java:1.8.0 (compression), org.apache.lucene:lucene‑core:10.5.0 (root POM) and 9.12.0 (common POM – version mismatch, likely intentional for compatibility).
• JaCoCo excludes — Updated package paths from io/github/hyshmily/hotkey/* to io/github/hyshmily/zeta/*.
• Main class — WorkerApplication moved to io.github.hyshmily.zeta.worker.

Removed / Deprecated

• evictLocal() — Replaced by invalidate(key, false).
• putBeforeInvalidate() — Replaced by invalidateAfterPut() with broadcast control.
• Batch computeIfAbsent(Collection, Function, ...) — Removed; use single‑key atomics plus new batch get() instead.
• HotKey* classes — All renamed to Zeta* (e.g., HotKeyCacheStats → ZetaCacheStats, HotKeyDecision → ZetaDecision).
• Old endpoint paths — /actuator/hotkey → /actuator/zeta, /actuator/hotkey/worker/state → /actuator/zeta/worker/state.