Add support for cache2k in memory caching

See gh-28498

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/cache/Cache2kCacheMeterBinderProvider.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2012-2022 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
+ *
+ *      https://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.metrics.cache;
+
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.binder.MeterBinder;
+import org.cache2k.extra.micrometer.Cache2kCacheMetrics;
+import org.cache2k.extra.spring.SpringCache2kCache;
+
+/**
+ * {@link CacheMeterBinderProvider} implementation for cache2k.
+ *
+ * @author Jens Wilke
+ * @since 2.7.0
+ */
+public class Cache2kCacheMeterBinderProvider implements CacheMeterBinderProvider<SpringCache2kCache> {
+
+	@Override
+	public MeterBinder getMeterBinder(SpringCache2kCache cache, Iterable<Tag> tags) {
+		return new Cache2kCacheMetrics(cache.getNativeCache(), tags);
+	}
+
+}

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/cache/Cache2kCacheMeterBinderProviderTests.java

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+/*
+ * Copyright 2012-2022 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
+ *
+ *      https://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.metrics.cache;
+
+import java.util.Collections;
+
+import io.micrometer.core.instrument.binder.MeterBinder;
+import org.cache2k.extra.micrometer.Cache2kCacheMetrics;
+import org.cache2k.extra.spring.SpringCache2kCacheManager;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link Cache2kCacheMeterBinderProvider}.
+ *
+ * @author Stephane Nicoll
+ */
+class Cache2kCacheMeterBinderProviderTests {
+
+	@Test
+	void cache2kCacheProvider() {
+		SpringCache2kCacheManager cacheManager = new SpringCache2kCacheManager()
+				.addCaches((builder) -> builder.name("test"));
+		MeterBinder meterBinder = new Cache2kCacheMeterBinderProvider().getMeterBinder(cacheManager.getCache("test"),
+				Collections.emptyList());
+		assertThat(meterBinder).isInstanceOf(Cache2kCacheMetrics.class);
+	}
+
+}