Add native hints for Caffeine cache. (#1194)

Author: OlgaMaciaszek

docs/src/main/asciidoc/spring-cloud-commons.adoc

@@ -635,7 +635,7 @@ public class MyClass {
 The Spring WebFlux can work with both reactive and non-reactive `WebClient` configurations, as the topics describe:
 
 * <<webflux-with-reactive-loadbalancer>>
-* <<load-balancer-exchange-filter-functionload-balancer-exchange-filter-function>>
+* <<load-balancer-exchange-filter-function>>
 
 [[webflux-with-reactive-loadbalancer]]
 ==== Spring WebFlux `WebClient` with `ReactorLoadBalancerExchangeFilterFunction`

spring-cloud-loadbalancer/src/main/java/org/springframework/cloud/loadbalancer/config/LoadBalancerCacheAutoConfiguration.java

@@ -16,12 +16,21 @@
 
 package org.springframework.cloud.loadbalancer.config;
 
+import java.util.Objects;
+import java.util.Set;
+import java.util.stream.Collectors;
+
 import com.github.benmanes.caffeine.cache.Caffeine;
 import com.stoyanr.evictor.ConcurrentMapWithTimedEviction;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.aot.hint.MemberCategory;
+import org.springframework.aot.hint.RuntimeHints;
+import org.springframework.aot.hint.RuntimeHintsRegistrar;
+import org.springframework.aot.hint.TypeReference;
 import org.springframework.beans.factory.InitializingBean;
+import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.AllNestedConditions;
@@ -39,8 +48,11 @@
 import org.springframework.cloud.loadbalancer.cache.LoadBalancerCacheManager;
 import org.springframework.cloud.loadbalancer.cache.LoadBalancerCacheProperties;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.core.type.filter.AssignableTypeFilter;
+import org.springframework.util.ClassUtils;
 
 /**
  * An AutoConfiguration that automatically enables caching when Spring Boot, and Spring
@@ -149,3 +161,52 @@ static class LoadBalancerCacheEnabled {
 	}
 
 }
+
+// Remove after adding hints to GraalVM reachability metadata repo
+class CaffeineHints implements RuntimeHintsRegistrar {
+
+	private static final Log LOG = LogFactory.getLog(CaffeineHints.class);
+
+	private static final String CAFFEINE_BOUNDED_LOCAL_CACHE_CLASS_NAME = "com.github.benmanes.caffeine.cache.BoundedLocalCache";
+
+	private static final String CAFFEINE_CACHE_BASE_PACKAGE = "com/github/benmanes/caffeine/cache";
+
+	private static final String CAFFEINE_NODE_CLASS_NAME = "com.github.benmanes.caffeine.cache.Node";
+
+	@Override
+	public void registerHints(RuntimeHints hints, ClassLoader classLoader) {
+		if (!ClassUtils.isPresent("com.github.benmanes.caffeine.cache.Caffeine", classLoader)) {
+			return;
+		}
+		hints.reflection()
+				.registerType(TypeReference.of(Caffeine.class),
+						hint -> hint.withMembers(MemberCategory.INVOKE_DECLARED_METHODS,
+								MemberCategory.INVOKE_DECLARED_CONSTRUCTORS, MemberCategory.DECLARED_FIELDS))
+				.registerType(TypeReference.of("com.github.benmanes.caffeine.cache.BoundedLocalCache"),
+						hint -> hint.withMembers(MemberCategory.INVOKE_DECLARED_METHODS,
+								MemberCategory.INVOKE_DECLARED_CONSTRUCTORS, MemberCategory.DECLARED_FIELDS))
+				.registerType(TypeReference.of("com.github.benmanes.caffeine.cache.LocalCacheFactory"),
+						hint -> hint.withMembers(MemberCategory.INVOKE_DECLARED_METHODS,
+								MemberCategory.INVOKE_DECLARED_CONSTRUCTORS, MemberCategory.DECLARED_FIELDS))
+				.registerType(TypeReference.of("com.github.benmanes.caffeine.cache.Node"),
+						hint -> hint.withMembers(MemberCategory.INVOKE_DECLARED_METHODS,
+								MemberCategory.INVOKE_DECLARED_CONSTRUCTORS, MemberCategory.DECLARED_FIELDS));
+		getCaffeineSubtypes().forEach(cacheType -> hints.reflection().registerType(TypeReference.of(cacheType),
+				hint -> hint.withMembers(MemberCategory.INVOKE_DECLARED_METHODS,
+						MemberCategory.INVOKE_DECLARED_CONSTRUCTORS, MemberCategory.DECLARED_FIELDS)));
+	}
+
+	private Set<String> getCaffeineSubtypes() {
+		ClassPathScanningCandidateComponentProvider provider = new ClassPathScanningCandidateComponentProvider(false);
+		try {
+			provider.addIncludeFilter(new AssignableTypeFilter(Class.forName(CAFFEINE_BOUNDED_LOCAL_CACHE_CLASS_NAME)));
+			provider.addIncludeFilter(new AssignableTypeFilter(Class.forName(CAFFEINE_NODE_CLASS_NAME)));
+		}
+		catch (ClassNotFoundException e) {
+			LOG.warn("Could not get class for name: " + CAFFEINE_BOUNDED_LOCAL_CACHE_CLASS_NAME);
+		}
+		return provider.findCandidateComponents(CAFFEINE_CACHE_BASE_PACKAGE).stream().filter(Objects::nonNull)
+				.map(BeanDefinition::getBeanClassName).filter(Objects::nonNull).collect(Collectors.toSet());
+	}
+
+}

spring-cloud-loadbalancer/src/main/resources/META-INF/spring/aot.factories

@@ -0,0 +1,2 @@
+org.springframework.aot.hint.RuntimeHintsRegistrar=\
+org.springframework.cloud.loadbalancer.config.CaffeineHints

spring-cloud-loadbalancer/src/test/java/org/springframework/cloud/loadbalancer/config/LoadBalancerCacheAutoConfigurationTests.java

@@ -38,7 +38,6 @@
  *
  * @author Olga Maciaszek-Sharma
  */
-
 class LoadBalancerCacheAutoConfigurationTests {
 
 	@Test