Improve performance of MessageSource condition

Update the MessageSourceAutoConfiguration condition to skip scanning for
well known JARs. Results are now also cached.

Fixes gh-1689

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/MessageSourceAutoConfiguration.java

@@ -17,6 +17,8 @@
 package org.springframework.boot.autoconfigure;
 
 import java.io.IOException;
+import java.util.Iterator;
+import java.util.Set;
 
 import org.springframework.boot.autoconfigure.MessageSourceAutoConfiguration.ResourceBundleCondition;
 import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
@@ -35,6 +37,7 @@ import org.springframework.core.annotation.Order;
 import org.springframework.core.io.Resource;
 import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
 import org.springframework.core.type.AnnotatedTypeMetadata;
+import org.springframework.util.ConcurrentReferenceHashMap;
 import org.springframework.util.StringUtils;
 
 import static org.springframework.util.StringUtils.commaDelimitedListToStringArray;
@@ -44,6 +47,7 @@ import static org.springframework.util.StringUtils.trimAllWhitespace;
  * {@link EnableAutoConfiguration Auto-configuration} for {@link MessageSource}.
  *
  * @author Dave Syer
+ * @author Phillip Webb
  */
 @Configuration
 @ConditionalOnMissingBean(MessageSource.class)
@@ -99,11 +103,23 @@ public class MessageSourceAutoConfiguration {
 
 	protected static class ResourceBundleCondition extends SpringBootCondition {
 
+		private static ConcurrentReferenceHashMap<String, ConditionOutcome> cache = new ConcurrentReferenceHashMap<String, ConditionOutcome>();
+
 		@Override
 		public ConditionOutcome getMatchOutcome(ConditionContext context,
 				AnnotatedTypeMetadata metadata) {
 			String basename = context.getEnvironment().getProperty(
 					"spring.messages.basename", "messages");
+			ConditionOutcome outcome = cache.get(basename);
+			if (outcome == null) {
+				outcome = getMatchOutcomeForBasename(context, basename);
+				cache.put(basename, outcome);
+			}
+			return outcome;
+		}
+
+		private ConditionOutcome getMatchOutcomeForBasename(ConditionContext context,
+				String basename) {
 			for (String name : commaDelimitedListToStringArray(trimAllWhitespace(basename))) {
 				for (Resource resource : getResources(context.getClassLoader(), name)) {
 					if (resource.exists()) {
@@ -118,7 +134,7 @@ public class MessageSourceAutoConfiguration {
 
 		private Resource[] getResources(ClassLoader classLoader, String name) {
 			try {
-				return new PathMatchingResourcePatternResolver(classLoader)
+				return new SkipPatternPathMatchingResourcePatternResolver(classLoader)
 						.getResources("classpath*:" + name + "*.properties");
 			}
 			catch (IOException ex) {
@@ -128,4 +144,60 @@ public class MessageSourceAutoConfiguration {
 
 	}
 
+	/**
+	 * {@link PathMatchingResourcePatternResolver} that skips well known JARs that don't
+	 * contain messages.properties.
+	 */
+	private static class SkipPatternPathMatchingResourcePatternResolver extends
+			PathMatchingResourcePatternResolver {
+
+		private static final ClassLoader ROOT_CLASSLOADER;
+		static {
+			ClassLoader classLoader = ClassLoader.getSystemClassLoader();
+			while (classLoader.getParent() != null) {
+				classLoader = classLoader.getParent();
+			}
+			ROOT_CLASSLOADER = classLoader;
+		}
+
+		private static final String[] SKIPPED = { "aspectjweaver-", "hibernate-core-",
+				"hsqldb-", "jackson-annotations-", "jackson-core-", "jackson-databind-",
+				"javassist-", "snakeyaml-", "spring-aop-", "spring-beans-",
+				"spring-boot-", "spring-boot-actuator-", "spring-boot-autoconfigure-",
+				"spring-core-", "spring-context-", "spring-data-commons-",
+				"spring-expression-", "spring-jdbc-", "spring-orm-", "spring-tx-",
+				"spring-web-", "spring-webmvc-", "tomcat-embed-", "joda-time-",
+				"hibernate-entitymanager-", "hibernate-validator-", "logback-classic-",
+				"logback-core-", "thymeleaf-" };
+
+		public SkipPatternPathMatchingResourcePatternResolver(ClassLoader classLoader) {
+			super(classLoader);
+		}
+
+		@Override
+		protected void addAllClassLoaderJarRoots(ClassLoader classLoader,
+				Set<Resource> result) {
+			if (classLoader != ROOT_CLASSLOADER) {
+				super.addAllClassLoaderJarRoots(classLoader, result);
+			}
+		};
+
+		@Override
+		protected Set<Resource> doFindAllClassPathResources(String path)
+				throws IOException {
+			Set<Resource> resources = super.doFindAllClassPathResources(path);
+			for (Iterator<Resource> iterator = resources.iterator(); iterator.hasNext();) {
+				Resource resource = iterator.next();
+				for (String skipped : SKIPPED) {
+					if (resource.getFilename().startsWith(skipped)) {
+						iterator.remove();
+						break;
+					}
+				}
+			}
+			return resources;
+		}
+
+	}
+
 }