Log cache hit and cache miss for synchronized access

Closes gh-25248

Author: snicoll

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

@@ -379,7 +379,7 @@ private Object execute(final CacheOperationInvoker invoker, Method method, Cache
 				Object key = generateKey(context, CacheOperationExpressionEvaluator.NO_RESULT);
 				Cache cache = context.getCaches().iterator().next();
 				try {
-					return wrapCacheValue(method, cache.get(key, () -> unwrapReturnValue(invokeOperation(invoker))));
+					return wrapCacheValue(method, handleSynchronizedGet(invoker, key, cache));
 				}
 				catch (Cache.ValueRetrievalException ex) {
 					// Directly propagate ThrowableWrapper from the invoker,
@@ -436,6 +436,22 @@ private Object execute(final CacheOperationInvoker invoker, Method method, Cache
 		return returnValue;
 	}
 
+	@Nullable
+	private Object handleSynchronizedGet(CacheOperationInvoker invoker, Object key, Cache cache) {
+		InvocationAwareResult invocationResult = new InvocationAwareResult();
+		Object result = cache.get(key, () -> {
+			invocationResult.invoked = true;
+			if (logger.isTraceEnabled()) {
+				logger.trace("No cache entry for key '" + key + "' in cache " + cache.getName());
+			}
+			return unwrapReturnValue(invokeOperation(invoker));
+		});
+		if (!invocationResult.invoked && logger.isTraceEnabled()) {
+			logger.trace("Cache entry for key '" + key + "' found in cache '" + cache.getName() + "'");
+		}
+		return result;
+	}
+
 	@Nullable
 	private Object wrapCacheValue(Method method, @Nullable Object cacheValue) {
 		if (method.getReturnType() == Optional.class &&
@@ -869,4 +885,13 @@ public int compareTo(CacheOperationCacheKey other) {
 		}
 	}
 
+	/**
+	 * Internal holder class for recording that a cache method was invoked.
+	 */
+	private static class InvocationAwareResult {
+
+		boolean invoked;
+
+	}
+
 }