WW-5716 Bound the per-locale definition caches in the Tiles plugin

[lukaszlenart]

The Tiles definition caches are keyed by the resolved Locale, which by default derives from the request. Two maps grew without limit and were never reduced for the lifetime of the web application:

• CachingLocaleUrlDefinitionDAO#locale2definitionMap — populated on each cache miss, only cleared under the (default-off) checkRefresh path.
• AbstractPatternDefinitionResolver#localePatternPaths — populated via computeIfAbsent per locale key, never swept.

The TilesContainer holding the DAO lives in application scope, so both maps persisted for the application lifetime, and the number of distinct keys was bounded only by the number of distinct locales encountered.

Change

• Bound locale2definitionMap with an insertion-order LinkedHashMap capped at maxCachedLocales (default 1000, configurable via setMaxCachedLocales). Insertion-order (not access-order) keeps the existing unsynchronized getDefinitions read unchanged.
• On eviction the DAO removes the same key from the pattern resolver through the new PatternDefinitionResolver#removePatternPaths, keeping both maps in lockstep — the resolver's keys are always a subset of the DAO's, since a pattern-paths entry is stored right before every locale2definitionMap put.
• localePatternPaths becomes a ConcurrentHashMap, as the DAO now removes keys off the request thread.

Eviction only re-incurs a load on next access; it never changes rendering. Both concrete resolvers (BasicPatternDefinitionResolver, PrefixedPatternDefinitionResolver) inherit the new behaviour from AbstractPatternDefinitionResolver.

Tests cover the bound and that both maps evict together; the full struts2-tiles-plugin module suite passes (547 tests).

Fixes WW-5716

🤖 Generated with Claude Code

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
93.8% Coverage on New Code
0.0% Duplication on New Code

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