WallpaperDetailBloomService

Info

@Service implementing a Redis-backed bloom filter with exact-set verification for wallpaper detail ID existence checks.

Overview

Pre-filters invalid wallpaper IDs before they reach the database, reducing cache-miss pressure from random or fabricated ID requests. Uses a two-layer approach identical to UserBanBloomService: bloom filter for fast negatives, Redis Set for exact verification.

Methods

Method	Description
mightContain(id)	Check if wallpaper ID exists (bloom filter + exact set)
add(id)	Add ID to both bloom filter and exact set
remove(id)	Remove ID from exact set only
rebuildFromIds(ids)	Rebuild entire bloom filter from a collection of active IDs

Configuration Properties

Property	Default	Description
wallpaper.detail.bloom.key	wallpaper:detail:bloom	Redis key for bloom filter bitmap
wallpaper.detail.set.key	wallpaper:detail:set	Redis key for exact ID set
wallpaper.detail.bloom.bit-size	2000003	Bloom filter bit array size (minimum 1024)
wallpaper.detail.bloom.hash-count	6	Number of hash functions (minimum 2)

Hash Strategy

• Hash 1: CRC32 of stringified ID
• Hash 2: Java String.hashCode() with #wallpaper-detail salt
• Combined: hash1 + i * hash2 + i * i (double hashing)

Lifecycle

• rebuildFromIds() is called during WallpaperMarketService construction to initialize the filter from all active wallpaper IDs
• add() is called when a new wallpaper is created
• remove() is called when a wallpaper is deleted

Dependencies

• wallpaperDetailBloomRedisTemplate -- Redis operations on dedicated DB 3