Added examples of cache usage

docs/antora.yml

@@ -17,3 +17,4 @@ asciidoc:
     chomp: 'all'
     include-java: 'example$docs-src/test/java/io/micrometer/docs'
     include-resources: 'example$docs-src/test/resources'
+    include-core-test-java: 'example$core-test'

docs/modules/ROOT/examples/core-test

@@ -0,0 +1 @@
+../../../../micrometer-core/src/test/java

docs/modules/ROOT/pages/reference/cache.adoc

@@ -1,5 +1,11 @@
+[[overview]]
+= Micrometer Cache Instrumentations
+
 Micrometer supports binding metrics to a variety of different popular caching libraries. Each implementation supports basic features, such as cache hits versus misses, from which you can derive basic information about the cache hit ratio over a period of time. Micrometer uses a function tracking counter to monitor such things as hits and misses, giving you a notion not only of hits and misses over the total life of the cache (the basic metric exposed from Guava's `CacheStats`, for example) but hits and misses inside a given interval.
 
+[[cache-example]]
+== Example
+
 To demonstrate the features of cache monitoring, we start with a simple program that uses `reactor-netty` to read the entirety of Mary Shelley's _Frankenstein_ and put each word in the cache if it has not yet been seen:
 
 ====
@@ -42,3 +48,91 @@ The following image shows the miss ratio when it exceeds 10%:
 
 .Alerting when the miss ratio exceeds 10%
 image::reference/cache/grafana-guava-miss-ratio.png[Miss ratio (alerted),width=800]
+
+== Cache implementations
+
+Micrometer can instrument various cache implementations
+
+* <<cache-caffeine, Caffeine>>
+* <<cache-ehcache, EhCache>>
+* <<cache-guava, Guava>>
+* <<cache-hazelcast, Hazelcast>>
+* <<cache-jcache, JCache>>
+
+[[cache-caffeine]]
+=== Caffeine
+
+[source,java,subs=+attributes]
+-----
+// Setting up instrumentation
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/CaffeineCacheMetricsTest.java[tags=setup, indent=0]
+
+// Binding manually
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/CaffeineCacheMetricsTest.java[tags=register, indent=0]
+
+// Binding through a static method
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/CaffeineCacheMetricsTest.java[tags=monitor, indent=0]
+-----
+
+[[cache-ehcache]]
+=== EhCache2
+
+[source,java,subs=+attributes]
+-----
+// Setting up instrumentation
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/EhCache2MetricsTest.java[tags=setup, indent=0]
+
+// Binding manually
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/EhCache2MetricsTest.java[tags=register, indent=0]
+
+// Binding through a static method
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/EhCache2MetricsTest.java[tags=monitor, indent=0]
+-----
+
+[[cache-guava]]
+=== Guava
+
+[source,java,subs=+attributes]
+-----
+// Setting up instrumentation
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/GuavaCacheMetricsTest.java[tags=setup, indent=0]
+
+// Binding manually
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/GuavaCacheMetricsTest.java[tags=register, indent=0]
+
+// Binding through a static method
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/GuavaCacheMetricsTest.java[tags=monitor, indent=0]
+-----
+
+[[cache-hazelcast]]
+=== Hazelcast
+
+[source,java,subs=+attributes]
+-----
+// Setting up instrumentation
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/HazelcastCacheMetricsTest.java[tags=setup, indent=0]
+
+// Binding manually
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/HazelcastCacheMetricsTest.java[tags=register, indent=0]
+
+// Binding through a static method
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/HazelcastCacheMetricsTest.java[tags=monitor, indent=0]
+-----
+
+[[cache-jcache]]
+=== JCache
+
+[source,java,subs=+attributes]
+-----
+// Setting up instrumentation
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/JCacheMetricsTest.java[tags=setup, indent=0]
+
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/JCacheMetricsTest.java[tags=setup_2, indent=0]
+
+// Binding manually
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/JCacheMetricsTest.java[tags=register, indent=0]
+
+// Binding through a static method
+include::{include-core-test-java}/io/micrometer/core/instrument/binder/cache/JCacheMetricsTest.java[tags=monitor, indent=0]
+-----
+

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/cache/CaffeineCacheMetricsTest.java

@@ -35,15 +35,19 @@
  */
 class CaffeineCacheMetricsTest extends AbstractCacheMetricsTest {
 
-    private LoadingCache<String, String> cache = Caffeine.newBuilder().build(key -> "");
+    // tag::setup[]
+    LoadingCache<String, String> cache = Caffeine.newBuilder().build(key -> "");
 
-    private CaffeineCacheMetrics<String, String, Cache<String, String>> metrics = new CaffeineCacheMetrics<>(cache,
+    CaffeineCacheMetrics<String, String, Cache<String, String>> metrics = new CaffeineCacheMetrics<>(cache,
             "testCache", expectedTag);
+    // end::setup[]
 
     @Test
     void reportExpectedGeneralMetrics() {
+        // tag::register[]
         MeterRegistry registry = new SimpleMeterRegistry();
         metrics.bindTo(registry);
+        // end::register[]
 
         verifyCommonCacheMetrics(registry, metrics);
 
@@ -64,8 +68,10 @@ void reportExpectedGeneralMetrics() {
 
     @Test
     void constructInstanceViaStaticMethodMonitor() {
+        // tag::monitor[]
         MeterRegistry meterRegistry = new SimpleMeterRegistry();
         CaffeineCacheMetrics.monitor(meterRegistry, cache, "testCache", expectedTag);
+        // end::monitor[]
 
         meterRegistry.get("cache.eviction.weight").tags(expectedTag).functionCounter();
     }

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/cache/EhCache2MetricsTest.java

@@ -41,14 +41,18 @@ class EhCache2MetricsTest extends AbstractCacheMetricsTest {
 
     private static CacheManager cacheManager;
 
-    private static Cache cache;
+    // tag::setup[]
+    static Cache cache;
 
-    private EhCache2Metrics metrics = new EhCache2Metrics(cache, expectedTag);
+    EhCache2Metrics metrics = new EhCache2Metrics(cache, expectedTag);
+    // end::setup[]
 
     @Test
     void reportMetrics() {
+        // tag::register[]
         MeterRegistry registry = new SimpleMeterRegistry();
         metrics.bindTo(registry);
+        // end::register[]
 
         verifyCommonCacheMetrics(registry, metrics);
 
@@ -117,8 +121,10 @@ void reportMetrics() {
 
     @Test
     void constructInstanceViaStaticMethodMonitor() {
+        // tag::monitor[]
         MeterRegistry meterRegistry = new SimpleMeterRegistry();
         EhCache2Metrics.monitor(meterRegistry, cache, expectedTag);
+        // end::monitor[]
 
         meterRegistry.get("cache.remoteSize").tags(expectedTag).gauge();
     }

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/cache/GuavaCacheMetricsTest.java

@@ -29,19 +29,23 @@
  */
 class GuavaCacheMetricsTest extends AbstractCacheMetricsTest {
 
-    private LoadingCache<String, String> cache = CacheBuilder.newBuilder().build(new CacheLoader<String, String>() {
+    // tag::setup[]
+    LoadingCache<String, String> cache = CacheBuilder.newBuilder().build(new CacheLoader<String, String>() {
         public String load(String key) throws Exception {
             return "";
         }
     });
 
-    private GuavaCacheMetrics<String, String, Cache<String, String>> metrics = new GuavaCacheMetrics<>(cache,
+    GuavaCacheMetrics<String, String, Cache<String, String>> metrics = new GuavaCacheMetrics<>(cache,
             "testCache", expectedTag);
+    // end::setup[]
 
     @Test
     void reportExpectedMetrics() {
+        // tag::register[]
         MeterRegistry registry = new SimpleMeterRegistry();
         metrics.bindTo(registry);
+        // end::register[]
 
         verifyCommonCacheMetrics(registry, metrics);
 
@@ -74,8 +78,10 @@ void reportExpectedMetrics() {
 
     @Test
     void constructInstanceViaStaticMethodMonitor() {
+        // tag::monitor[]
         MeterRegistry meterRegistry = new SimpleMeterRegistry();
         GuavaCacheMetrics.monitor(meterRegistry, cache, "testCache", expectedTag);
+        // end::monitor[]
 
         meterRegistry.get("cache.load.duration").tags(expectedTag).timeGauge();
     }

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/cache/HazelcastCacheMetricsTest.java

@@ -43,14 +43,18 @@
  */
 class HazelcastCacheMetricsTest extends AbstractCacheMetricsTest {
 
-    private static IMap<String, String> cache;
+    // tag::setup[]
+    static IMap<String, String> cache;
 
-    private HazelcastCacheMetrics metrics = new HazelcastCacheMetrics(cache, expectedTag);
+    HazelcastCacheMetrics metrics = new HazelcastCacheMetrics(cache, expectedTag);
+    // end::setup[]
 
     @Test
     void reportMetrics() {
+        // tag::register[]
         MeterRegistry meterRegistry = new SimpleMeterRegistry();
         metrics.bindTo(meterRegistry);
+        // end::register[]
 
         verifyCommonCacheMetrics(meterRegistry, metrics);
 
@@ -102,8 +106,10 @@ void reportMetrics() {
 
     @Test
     void constructInstanceViaStaticMethodMonitor() {
+        // tag::monitor[]
         MeterRegistry meterRegistry = new SimpleMeterRegistry();
         HazelcastCacheMetrics.monitor(meterRegistry, cache, expectedTag);
+        // end::monitor[]
 
         meterRegistry.get("cache.partition.gets").tags(expectedTag).functionCounter();
     }

micrometer-core/src/test/java/io/micrometer/core/instrument/binder/cache/JCacheMetricsTest.java

@@ -41,22 +41,28 @@
 class JCacheMetricsTest extends AbstractCacheMetricsTest {
 
     @SuppressWarnings("unchecked")
-    private Cache<String, String> cache = mock(Cache.class);
+    // tag::setup[]
+    Cache<String, String> cache;
 
-    private CacheManager cacheManager = mock(CacheManager.class);
+    JCacheMetrics<String, String, Cache<String, String>> metrics;
+    // end::setup[]
 
-    private JCacheMetrics<String, String, Cache<String, String>> metrics;
+    private CacheManager cacheManager;
 
     private MBeanServer mbeanServer;
 
     private Long expectedAttributeValue = new Random().nextLong();
 
     @BeforeEach
     void setup() throws Exception {
+        cache = mock(Cache.class);
+        cacheManager = mock(CacheManager.class);
         when(cache.getCacheManager()).thenReturn(cacheManager);
         when(cache.getName()).thenReturn("testCache");
         when(cacheManager.getURI()).thenReturn(new URI("http://localhost"));
+        // tag::setup_2[]
         metrics = new JCacheMetrics<>(cache, expectedTag);
+        // end::setup_2[]
 
         // emulate MBean server with MBean used for statistic lookup
         mbeanServer = MBeanServerFactory.createMBeanServer();
@@ -75,8 +81,10 @@ void tearDown() {
 
     @Test
     void reportExpectedMetrics() {
+        // tag::register[]
         MeterRegistry meterRegistry = new SimpleMeterRegistry();
         metrics.bindTo(meterRegistry);
+        // end::register[]
 
         verifyCommonCacheMetrics(meterRegistry, metrics);
 
@@ -86,8 +94,10 @@ void reportExpectedMetrics() {
 
     @Test
     void constructInstanceViaStaticMethodMonitor() {
+        // tag::monitor[]
         MeterRegistry meterRegistry = new SimpleMeterRegistry();
         JCacheMetrics.monitor(meterRegistry, cache, expectedTag);
+        // end::monitor[]
 
         meterRegistry.get("cache.removals").tags(expectedTag).gauge();
     }