Polish ConcurrentReferenceCachingMetadataReaderFactory to use Map::computeIfAbsent

Author: quaff

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/type/classreading/ConcurrentReferenceCachingMetadataReaderFactory.java

@@ -26,6 +26,7 @@
 import org.springframework.core.type.classreading.MetadataReaderFactory;
 import org.springframework.core.type.classreading.SimpleMetadataReaderFactory;
 import org.springframework.util.ConcurrentReferenceHashMap;
+import org.springframework.util.function.ThrowingFunction;
 
 /**
  * Caching implementation of the {@link MetadataReaderFactory} interface backed by a
@@ -70,22 +71,14 @@ public ConcurrentReferenceCachingMetadataReaderFactory(ClassLoader classLoader)
 
 	@Override
 	public MetadataReader getMetadataReader(String className) throws IOException {
-		MetadataReader metadataReader = this.classNameCache.get(className);
-		if (metadataReader == null) {
-			metadataReader = super.getMetadataReader(className);
-			this.classNameCache.put(className, metadataReader);
-		}
-		return metadataReader;
+		return this.classNameCache.computeIfAbsent(className,
+				(ThrowingFunction<String, MetadataReader>) super::getMetadataReader);
 	}
 
 	@Override
 	public MetadataReader getMetadataReader(Resource resource) throws IOException {
-		MetadataReader metadataReader = this.resourceCache.get(resource);
-		if (metadataReader == null) {
-			metadataReader = createMetadataReader(resource);
-			this.resourceCache.put(resource, metadataReader);
-		}
-		return metadataReader;
+		return this.resourceCache.computeIfAbsent(resource,
+				(ThrowingFunction<Resource, MetadataReader>) this::createMetadataReader);
 	}
 
 	/**