HHH-12529 - Some StatisticsImpl methods throw an exception instead of returning null

Author: sebersole

hibernate-core/src/main/java/org/hibernate/stat/internal/StatisticsImpl.java

@@ -625,10 +625,12 @@ public CacheRegionStatisticsImpl getCacheRegionStatistics(String regionName) {
 		return l2CacheStatsMap.computeIfAbsent(
 				regionName,
 				s -> {
-					final Region region = sessionFactory.getCache().getRegion( regionName );
+					Region region = sessionFactory.getCache().getRegion( regionName );
 
 					if ( region == null ) {
-						throw new IllegalArgumentException( "Unknown cache region : " + regionName );
+						// this is the pre-5.3 behavior.  and since this is a pre-5.3 method it should behave consistently
+						// NOTE that this method is deprecated
+						region = sessionFactory.getCache().getQueryResultsCache( regionName ).getRegion();
 					}
 
 					return new CacheRegionStatisticsImpl( region );
@@ -638,6 +640,9 @@ public CacheRegionStatisticsImpl getCacheRegionStatistics(String regionName) {
 
 	@Override
 	public CacheRegionStatisticsImpl getSecondLevelCacheStatistics(String regionName) {
+		if ( sessionFactory == null ) {
+			return null;
+		}
 		return getCacheRegionStatistics( sessionFactory.getCache().unqualifyRegionName( regionName ) );
 	}
 

hibernate-core/src/test/java/org/hibernate/test/cache/RegionNameTest.java

@@ -82,6 +82,9 @@ public void testLegacyStatsApi() {
 
 		final NaturalIdCacheStatistics naturalIdCacheStatistics = stats.getNaturalIdCacheStatistics( regionName );
 		assert naturalIdCacheStatistics != null;
+
+		final SecondLevelCacheStatistics dne = stats.getSecondLevelCacheStatistics( cachePrefix + ".does.not.exist" );
+		assert dne != null;
 	}
 
 	// todo (5.3) : any other API I can think of that deals with region-name?