Add cache-related logs

Add a trace log for cache hit and cache miss events.

Issue: SPR-11654

Author: snicoll

spring-context/src/main/java/org/springframework/cache/interceptor/CacheAspectSupport.java

@@ -435,6 +435,11 @@ private Cache.ValueWrapper findCachedItem(Collection<CacheOperationContext> cont
 				if (cached != null) {
 					return cached;
 				}
+				else {
+					if (logger.isTraceEnabled()) {
+						logger.trace("No cache entry for key '" + key + "' in cache(s) " + context.getCacheNames());
+					}
+				}
 			}
 		}
 		return null;
@@ -462,6 +467,9 @@ private Cache.ValueWrapper findInCaches(CacheOperationContext context, Object ke
 		for (Cache cache : context.getCaches()) {
 			Cache.ValueWrapper wrapper = doGet(cache, key);
 			if (wrapper != null) {
+				if (logger.isTraceEnabled()) {
+					logger.trace("Cache entry for key '" + key + "' found in cache '" + cache.getName() + "'");
+				}
 				return wrapper;
 			}
 		}
@@ -484,7 +492,7 @@ private Object generateKey(CacheOperationContext context, Object result) {
 					"using named params on classes without debug info?) " + context.metadata.operation);
 		}
 		if (logger.isTraceEnabled()) {
-			logger.trace("Computed cache key " + key + " for operation " + context.metadata.operation);
+			logger.trace("Computed cache key '" + key + "' for operation " + context.metadata.operation);
 		}
 		return key;
 	}
@@ -548,13 +556,16 @@ protected class CacheOperationContext implements CacheOperationInvocationContext
 
 		private final Collection<? extends Cache> caches;
 
+		private final Collection<String> cacheNames;
+
 		private final AnnotatedElementKey methodCacheKey;
 
 		public CacheOperationContext(CacheOperationMetadata metadata, Object[] args, Object target) {
 			this.metadata = metadata;
 			this.args = extractArgs(metadata.method, args);
 			this.target = target;
 			this.caches = CacheAspectSupport.this.getCaches(this, metadata.cacheResolver);
+			this.cacheNames = createCacheNames(this.caches);
 			this.methodCacheKey = new AnnotatedElementKey(metadata.method, metadata.targetClass);
 		}
 
@@ -633,6 +644,18 @@ private EvaluationContext createEvaluationContext(Object result) {
 		protected Collection<? extends Cache> getCaches() {
 			return this.caches;
 		}
+
+		protected Collection<String> getCacheNames() {
+			return this.cacheNames;
+		}
+
+		private Collection<String> createCacheNames(Collection<? extends Cache> caches) {
+			Collection<String> names = new ArrayList<String>();
+			for (Cache cache : caches) {
+				names.add(cache.getName());
+			}
+			return names;
+		}
 	}