Tolerate Hazelcast 4

This commit updates HazelcastHealthIndicator and
HazelcastCacheMeterBinderProvider so that they work with
Hazelcast 4 while retaining compatibility with Hazelcast 3. Reflection
is used when necessary.

This commit also adds a smoke test that validates those features are
working when Hazelcast 4 is on the classpath.

Closes gh-21169

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/hazelcast/HazelcastHealthIndicator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -16,12 +16,16 @@
 
 package org.springframework.boot.actuate.hazelcast;
 
+import java.lang.reflect.Method;
+import java.util.UUID;
+
 import com.hazelcast.core.HazelcastInstance;
 
 import org.springframework.boot.actuate.health.AbstractHealthIndicator;
 import org.springframework.boot.actuate.health.Health;
 import org.springframework.boot.actuate.health.HealthIndicator;
 import org.springframework.util.Assert;
+import org.springframework.util.ReflectionUtils;
 
 /**
  * {@link HealthIndicator} for Hazelcast.
@@ -43,10 +47,22 @@ public class HazelcastHealthIndicator extends AbstractHealthIndicator {
 	@Override
 	protected void doHealthCheck(Health.Builder builder) {
 		this.hazelcast.executeTransaction((context) -> {
-			builder.up().withDetail("name", this.hazelcast.getName()).withDetail("uuid",
-					this.hazelcast.getLocalEndpoint().getUuid());
+			builder.up().withDetail("name", this.hazelcast.getName()).withDetail("uuid", extractUuid());
 			return null;
 		});
 	}
 
+	private String extractUuid() {
+		try {
+			return this.hazelcast.getLocalEndpoint().getUuid();
+		}
+		catch (NoSuchMethodError ex) {
+			// Hazelcast 4
+			Method endpointAccessor = ReflectionUtils.findMethod(HazelcastInstance.class, "getLocalEndpoint");
+			Object endpoint = ReflectionUtils.invokeMethod(endpointAccessor, this.hazelcast);
+			Method uuidAccessor = ReflectionUtils.findMethod(endpoint.getClass(), "getUuid");
+			return ((UUID) ReflectionUtils.invokeMethod(uuidAccessor, endpoint)).toString();
+		}
+	}
+
 }

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

@@ -16,11 +16,15 @@
 
 package org.springframework.boot.actuate.metrics.cache;
 
+import java.lang.reflect.Method;
+
 import com.hazelcast.spring.cache.HazelcastCache;
 import io.micrometer.core.instrument.Tag;
 import io.micrometer.core.instrument.binder.MeterBinder;
 import io.micrometer.core.instrument.binder.cache.HazelcastCacheMetrics;
 
+import org.springframework.util.ReflectionUtils;
+
 /**
  * {@link CacheMeterBinderProvider} implementation for Hazelcast.
  *
@@ -31,7 +35,25 @@ public class HazelcastCacheMeterBinderProvider implements CacheMeterBinderProvid
 
 	@Override
 	public MeterBinder getMeterBinder(HazelcastCache cache, Iterable<Tag> tags) {
-		return new HazelcastCacheMetrics(cache.getNativeCache(), tags);
+		try {
+			return new HazelcastCacheMetrics(cache.getNativeCache(), tags);
+		}
+		catch (NoSuchMethodError ex) {
+			// Hazelcast 4
+			return createHazelcast4CacheMetrics(cache, tags);
+		}
+	}
+
+	private MeterBinder createHazelcast4CacheMetrics(HazelcastCache cache, Iterable<Tag> tags) {
+		try {
+			Method nativeCacheAccessor = ReflectionUtils.findMethod(HazelcastCache.class, "getNativeCache");
+			Object nativeCache = ReflectionUtils.invokeMethod(nativeCacheAccessor, cache);
+			return HazelcastCacheMetrics.class.getConstructor(Object.class, Iterable.class).newInstance(nativeCache,
+					tags);
+		}
+		catch (Exception ex) {
+			throw new IllegalStateException("Failed to create MeterBinder for Hazelcast", ex);
+		}
 	}
 
 }