Polish CachePublicMetrics

CachePublicMetrics wasn't explicitly tested and was still using field
injection. This commit improves the situation in preparation of the fix
for gh-8984

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/CachePublicMetrics.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -45,6 +45,15 @@ public class CachePublicMetrics implements PublicMetrics {
 	@Autowired
 	private Collection<CacheStatisticsProvider<?>> statisticsProviders;
 
+	public CachePublicMetrics() {
+	}
+
+	public CachePublicMetrics(Map<String, CacheManager> cacheManagers,
+			Collection<CacheStatisticsProvider<?>> statisticsProviders) {
+		this.cacheManagers = cacheManagers;
+		this.statisticsProviders = statisticsProviders;
+	}
+
 	@Override
 	public Collection<Metric<?>> metrics() {
 		Collection<Metric<?>> metrics = new HashSet<Metric<?>>();

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/endpoint/CachePublicMetricsTests.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2012-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.actuate.endpoint;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.boot.actuate.cache.CacheStatisticsProvider;
+import org.springframework.boot.actuate.cache.CaffeineCacheStatisticsProvider;
+import org.springframework.boot.actuate.cache.ConcurrentMapCacheStatisticsProvider;
+import org.springframework.boot.actuate.metrics.Metric;
+import org.springframework.cache.CacheManager;
+import org.springframework.cache.concurrent.ConcurrentMapCacheManager;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
+
+/**
+ * Tests for {@link CachePublicMetrics}
+ *
+ * @author Stephane Nicoll
+ */
+public class CachePublicMetricsTests {
+
+	private Map<String, CacheManager> cacheManagers = new HashMap<String, CacheManager>();
+
+	@Before
+	public void setup() {
+		this.cacheManagers.put("cacheManager",
+				new ConcurrentMapCacheManager("foo", "bar"));
+	}
+
+	@Test
+	public void cacheMetricsWithMatchingProvider() {
+		CachePublicMetrics cpm = new CachePublicMetrics(this.cacheManagers,
+				providers(new ConcurrentMapCacheStatisticsProvider()));
+		Map<String, Number> metrics = metrics(cpm);
+		assertThat(metrics).containsOnly(entry("cache.foo.size", 0L),
+				entry("cache.bar.size", 0L));
+	}
+
+	@Test
+	public void cacheMetricsWithNoMatchingProvider() {
+		CachePublicMetrics cpm = new CachePublicMetrics(this.cacheManagers,
+				providers(new CaffeineCacheStatisticsProvider()));
+		Map<String, Number> metrics = metrics(cpm);
+		assertThat(metrics).isEmpty();
+	}
+
+	@Test
+	public void cacheMetricsWithMultipleCacheManagers() {
+		this.cacheManagers.put("anotherCacheManager",
+				new ConcurrentMapCacheManager("foo"));
+		CachePublicMetrics cpm = new CachePublicMetrics(this.cacheManagers,
+				providers(new ConcurrentMapCacheStatisticsProvider()));
+		Map<String, Number> metrics = metrics(cpm);
+		assertThat(metrics).containsOnly(entry("cache.cacheManager_foo.size", 0L),
+				entry("cache.bar.size", 0L),
+				entry("cache.anotherCacheManager_foo.size", 0L));
+	}
+
+
+	private Map<String, Number> metrics(CachePublicMetrics cpm) {
+		Collection<Metric<?>> metrics = cpm.metrics();
+		assertThat(metrics).isNotNull();
+		Map<String, Number> result = new HashMap<String, Number>();
+		for (Metric<?> metric : metrics) {
+			result.put(metric.getName(), metric.getValue());
+		}
+		return result;
+	}
+
+	private Collection<CacheStatisticsProvider<?>> providers(
+			CacheStatisticsProvider<?>... providers) {
+		return Arrays.asList(providers);
+	}
+
+}