diff --git a/src/main/java/org/springframework/samples/petclinic/system/CacheConfiguration.java b/src/main/java/org/springframework/samples/petclinic/system/CacheConfiguration.java index e4d7b42425430f4276a23378cec6fa4404460ba5..adde2bebdd5685ef5f309cd50c7e1ff6a9c14a65 100755 --- a/src/main/java/org/springframework/samples/petclinic/system/CacheConfiguration.java +++ b/src/main/java/org/springframework/samples/petclinic/system/CacheConfiguration.java @@ -7,10 +7,38 @@ import org.springframework.cache.annotation.EnableCaching; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; +/** + * Cache configuration intended for caches providing the JCache API. This configuration + * creates the used cache for the application and enables statistics that + * become accessible via JMX. + * + * <p>This is a minimal configuration that makes use of the JCache API to enable + * caching with any JCache implementation out of the box. The utilized JCache implementation + * is specified by the dependency in the {@code pom.xml}. + * + * <p>If the used cache implementation is configured via its specific and non standard mechanism, + * this example configuration might be redundant and can be removed or replaced by + * a programmatic configuration via the implementation specific methods. + * + * <p>In case no programmatic cache configuration is needed for the selected caching + * implementation this configuration class can be removed and the {@link EnableCaching} + * annotation can be put on the application class. + * + * @author Jens Wilke + */ @Configuration @EnableCaching class CacheConfiguration { + /** + * A customizer that creates the the cache used by the application. + * This implies that the cache is not existent before the application start and the + * cache must be created. This is the default behavior of a JCache implemenation, in case + * no additional configuration is present and typically will create a transient in memory cache. + * If a persistent cache implementation is used, creating the cache on startup + * may lead to a failure, when the cache was created before. If the cache life time + * is controlled separately, the call of {@code createCache} must be removed. + */ @Bean public JCacheManagerCustomizer petclinicCacheConfigurationCustomizer() { return cm -> { @@ -18,9 +46,14 @@ class CacheConfiguration { }; } + /** + * Enable statistics via the JCache programmatic configuration API. + * Within the configuration object that is provided by the JCache API standard, there is only + * a very limited set of configuration options. The really relevant configuration options + * (like the size limit) must be set via a configuration mechanism that is provided by the + * selected JCache implementation. + */ private javax.cache.configuration.Configuration<Object, Object> cacheConfiguration() { - // Create a cache using infinite heap. A real application will want to use a more fine-grained configuration, - // possibly using an implementation-dependent API return new MutableConfiguration<>().setStatisticsEnabled(true); }