Introduced DefaultParameterNameDiscoverer which checks JDK 8's standard reflection first and then falls back to ASM-based debug symbol analysis

Also, StandardReflectionParameterNameDiscoverer calls "Parameter.isNamePresent()" now to return null (and pass on to the next discoverer) if no JDK 8 parameters are available. Note that this requires OpenJDK 8 b100 or higher to compile now.

Issue: SPR-10532

spring-aop/src/main/java/org/springframework/aop/aspectj/AbstractAspectJAdvice.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 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.
@@ -37,9 +37,8 @@ import org.springframework.aop.interceptor.ExposeInvocationInterceptor;
 import org.springframework.aop.support.ComposablePointcut;
 import org.springframework.aop.support.MethodMatchers;
 import org.springframework.aop.support.StaticMethodMatcher;
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
+import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.ParameterNameDiscoverer;
-import org.springframework.core.PrioritizedParameterNameDiscoverer;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.CollectionUtils;
@@ -435,15 +434,13 @@ public abstract class AbstractAspectJAdvice implements Advice, AspectJPrecedence
 
 	/**
 	 * Create a ParameterNameDiscoverer to be used for argument binding.
-	 * <p>The default implementation creates a {@link PrioritizedParameterNameDiscoverer}
-	 * containing a {@link LocalVariableTableParameterNameDiscoverer} and an
-	 * {@link AspectJAdviceParameterNameDiscoverer}.
+	 * <p>The default implementation creates a {@link DefaultParameterNameDiscoverer}
+	 * and adds a specifically configured {@link AspectJAdviceParameterNameDiscoverer}.
 	 */
 	protected ParameterNameDiscoverer createParameterNameDiscoverer() {
 		// We need to discover them, or if that fails, guess,
 		// and if we can't guess with 100% accuracy, fail.
-		PrioritizedParameterNameDiscoverer discoverer = new PrioritizedParameterNameDiscoverer();
-		discoverer.addDiscoverer(new LocalVariableTableParameterNameDiscoverer());
+		DefaultParameterNameDiscoverer discoverer = new DefaultParameterNameDiscoverer();
 		AspectJAdviceParameterNameDiscoverer adviceParameterNameDiscoverer =
 				new AspectJAdviceParameterNameDiscoverer(this.pointcut.getExpression());
 		adviceParameterNameDiscoverer.setReturningName(this.returningName);

spring-aop/src/main/java/org/springframework/aop/aspectj/MethodInvocationProceedingJoinPoint.java

@@ -27,7 +27,8 @@ import org.aspectj.lang.reflect.SourceLocation;
 import org.aspectj.runtime.internal.AroundClosure;
 
 import org.springframework.aop.ProxyMethodInvocation;
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
+import org.springframework.core.DefaultParameterNameDiscoverer;
+import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.util.Assert;
 
 /**
@@ -51,6 +52,8 @@ import org.springframework.util.Assert;
  */
 public class MethodInvocationProceedingJoinPoint implements ProceedingJoinPoint, JoinPoint.StaticPart {
 
+	private static final ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
+
 	private final ProxyMethodInvocation methodInvocation;
 
 	private Object[] defensiveCopyOfArgs;
@@ -213,7 +216,7 @@ public class MethodInvocationProceedingJoinPoint implements ProceedingJoinPoint,
 		@Override
 		public String[] getParameterNames() {
 			if (this.parameterNames == null) {
-				this.parameterNames = (new LocalVariableTableParameterNameDiscoverer()).getParameterNames(getMethod());
+				this.parameterNames = parameterNameDiscoverer.getParameterNames(getMethod());
 			}
 			return this.parameterNames;
 		}

spring-aop/src/main/java/org/springframework/aop/aspectj/annotation/AbstractAspectJAdvisorFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2013 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.
@@ -59,9 +59,6 @@ import org.springframework.util.StringUtils;
  */
 public abstract class AbstractAspectJAdvisorFactory implements AspectJAdvisorFactory {
 
-	protected static final ParameterNameDiscoverer ASPECTJ_ANNOTATION_PARAMETER_NAME_DISCOVERER =
-			new AspectJAnnotationParameterNameDiscoverer();
-
 	private static final String AJC_MAGIC = "ajc$";
 
 
@@ -96,14 +93,8 @@ public abstract class AbstractAspectJAdvisorFactory implements AspectJAdvisorFac
 	/** Logger available to subclasses */
 	protected final Log logger = LogFactory.getLog(getClass());
 
-	protected final ParameterNameDiscoverer parameterNameDiscoverer;
-
+	protected final ParameterNameDiscoverer parameterNameDiscoverer = new AspectJAnnotationParameterNameDiscoverer();
 
-	protected AbstractAspectJAdvisorFactory() {
-		PrioritizedParameterNameDiscoverer prioritizedParameterNameDiscoverer = new PrioritizedParameterNameDiscoverer();
-		prioritizedParameterNameDiscoverer.addDiscoverer(ASPECTJ_ANNOTATION_PARAMETER_NAME_DISCOVERER);
-		this.parameterNameDiscoverer = prioritizedParameterNameDiscoverer;
-	}
 
 	/**
 	 * We consider something to be an AspectJ aspect suitable for use by the Spring AOP system

spring-beans/src/main/java/org/springframework/beans/factory/support/AbstractAutowireCapableBeanFactory.java

@@ -68,8 +68,8 @@ import org.springframework.beans.factory.config.DependencyDescriptor;
 import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessor;
 import org.springframework.beans.factory.config.SmartInstantiationAwareBeanPostProcessor;
 import org.springframework.beans.factory.config.TypedStringValue;
+import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.GenericTypeResolver;
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.core.PriorityOrdered;
@@ -120,7 +120,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	private InstantiationStrategy instantiationStrategy = new CglibSubclassingInstantiationStrategy();
 
 	/** Resolver strategy for method parameter names */
-	private ParameterNameDiscoverer parameterNameDiscoverer = new LocalVariableTableParameterNameDiscoverer();
+	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
 
 	/** Whether to automatically try to resolve circular references between beans */
 	private boolean allowCircularReferences = true;
@@ -191,7 +191,7 @@ public abstract class AbstractAutowireCapableBeanFactory extends AbstractBeanFac
 	/**
 	 * Set the ParameterNameDiscoverer to use for resolving method parameter
 	 * names if needed (e.g. for constructor names).
-	 * <p>The default is {@link LocalVariableTableParameterNameDiscoverer}.
+	 * <p>Default is a {@link DefaultParameterNameDiscoverer}.
 	 */
 	public void setParameterNameDiscoverer(ParameterNameDiscoverer parameterNameDiscoverer) {
 		this.parameterNameDiscoverer = parameterNameDiscoverer;

spring-context/src/main/java/org/springframework/cache/interceptor/ExpressionEvaluator.java

@@ -22,7 +22,7 @@ import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
 import org.springframework.cache.Cache;
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
+import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.expression.EvaluationContext;
 import org.springframework.expression.Expression;
@@ -46,7 +46,7 @@ class ExpressionEvaluator {
 	private final SpelExpressionParser parser = new SpelExpressionParser();
 
 	// shared param discoverer since it caches data internally
-	private final ParameterNameDiscoverer paramNameDiscoverer = new LocalVariableTableParameterNameDiscoverer();
+	private final ParameterNameDiscoverer paramNameDiscoverer = new DefaultParameterNameDiscoverer();
 
 	private final Map<String, Expression> keyCache = new ConcurrentHashMap<String, Expression>(64);
 

spring-context/src/main/java/org/springframework/jmx/export/assembler/AbstractReflectiveMBeanInfoAssembler.java

@@ -30,7 +30,7 @@ import javax.management.modelmbean.ModelMBeanOperationInfo;
 import org.springframework.aop.framework.AopProxyUtils;
 import org.springframework.aop.support.AopUtils;
 import org.springframework.beans.BeanUtils;
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
+import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.jmx.support.JmxUtils;
 
@@ -180,7 +180,7 @@ public abstract class AbstractReflectiveMBeanInfoAssembler extends AbstractMBean
 
 	private boolean exposeClassDescriptor = false;
 
-	private ParameterNameDiscoverer parameterNameDiscoverer = new LocalVariableTableParameterNameDiscoverer();
+	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
 
 
 	/**
@@ -262,7 +262,7 @@ public abstract class AbstractReflectiveMBeanInfoAssembler extends AbstractMBean
 	/**
 	 * Set the ParameterNameDiscoverer to use for resolving method parameter
 	 * names if needed (e.g. for parameter names of MBean operation methods).
-	 * <p>The default is {@link LocalVariableTableParameterNameDiscoverer}.
+	 * <p>Default is a {@link DefaultParameterNameDiscoverer}.
 	 */
 	public void setParameterNameDiscoverer(ParameterNameDiscoverer parameterNameDiscoverer) {
 		this.parameterNameDiscoverer = parameterNameDiscoverer;

spring-context/src/main/java/org/springframework/validation/beanvalidation/LocalValidatorFactoryBean.java

@@ -42,7 +42,7 @@ import org.springframework.beans.factory.InitializingBean;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.MessageSource;
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
+import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.core.io.Resource;
 import org.springframework.util.ClassUtils;
@@ -93,7 +93,7 @@ public class LocalValidatorFactoryBean extends SpringValidatorAdapter
 
 	private ConstraintValidatorFactory constraintValidatorFactory;
 
-	private ParameterNameDiscoverer parameterNameDiscoverer;
+	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
 
 	private Resource[] mappingLocations;
 
@@ -161,7 +161,7 @@ public class LocalValidatorFactoryBean extends SpringValidatorAdapter
 	/**
 	 * Set the ParameterNameDiscoverer to use for resolving method and constructor
 	 * parameter names if needed for message interpolation.
-	 * <p>Default is a {@link org.springframework.core.LocalVariableTableParameterNameDiscoverer}.
+	 * <p>Default is a {@link org.springframework.core.DefaultParameterNameDiscoverer}.
 	 */
 	public void setParameterNameDiscoverer(ParameterNameDiscoverer parameterNameDiscoverer) {
 		this.parameterNameDiscoverer = parameterNameDiscoverer;
@@ -269,8 +269,7 @@ public class LocalValidatorFactoryBean extends SpringValidatorAdapter
 					Configuration.class.getMethod("parameterNameProvider", parameterNameProviderClass);
 			final Object defaultProvider = ReflectionUtils.invokeMethod(
 					Configuration.class.getMethod("getDefaultParameterNameProvider"), configuration);
-			final ParameterNameDiscoverer discoverer = (this.parameterNameDiscoverer != null ?
-					this.parameterNameDiscoverer : new LocalVariableTableParameterNameDiscoverer());
+			final ParameterNameDiscoverer discoverer = this.parameterNameDiscoverer;
 			Object parameterNameProvider = Proxy.newProxyInstance(getClass().getClassLoader(),
 					new Class[] {parameterNameProviderClass}, new InvocationHandler() {
 				@Override

spring-core/src/main/java/org/springframework/core/DefaultParameterNameDiscoverer.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2002-2013 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
+ *
+ *      http://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.core;
+
+/**
+ * Default implementation of the {@link ParameterNameDiscoverer} strategy interface,
+ * using the Java 8 standard reflection mechanism (if available), and falling back
+ * to the ASM-based {@link LocalVariableTableParameterNameDiscoverer} for checking
+ * debug information in the class file.
+ *
+ * <p>Further discoverers may be added through {@link #addDiscoverer(ParameterNameDiscoverer)}.
+ *
+ * @author Juergen Hoeller
+ * @since 4.0
+ * @see StandardReflectionParameterNameDiscoverer
+ * @see LocalVariableTableParameterNameDiscoverer
+ */
+public class DefaultParameterNameDiscoverer extends PrioritizedParameterNameDiscoverer {
+
+	private static final boolean standardReflectionAvailable =
+			(JdkVersion.getMajorJavaVersion() >= JdkVersion.JAVA_18);
+
+
+	public DefaultParameterNameDiscoverer() {
+		if (standardReflectionAvailable) {
+			addDiscoverer(new StandardReflectionParameterNameDiscoverer());
+		}
+		addDiscoverer(new LocalVariableTableParameterNameDiscoverer());
+	}
+
+}

spring-core/src/main/java/org/springframework/core/StandardReflectionParameterNameDiscoverer.java

@@ -20,6 +20,8 @@ import java.lang.reflect.Constructor;
 import java.lang.reflect.Method;
 import java.lang.reflect.Parameter;
 
+import org.springframework.util.ClassUtils;
+
 /**
  * {@link ParameterNameDiscoverer} implementation which uses JDK 8's
  * reflection facilities for introspecting parameter names.
@@ -35,7 +37,11 @@ public class StandardReflectionParameterNameDiscoverer implements ParameterNameD
 		Parameter[] parameters = method.getParameters();
 		String[] parameterNames = new String[parameters.length];
 		for (int i = 0; i < parameters.length; i++) {
-			parameterNames[i] = parameters[i].getName();
+			Parameter param = parameters[i];
+			if (!param.isNamePresent()) {
+				return null;
+			}
+			parameterNames[i] = param.getName();
 		}
 		return parameterNames;
 	}
@@ -45,7 +51,11 @@ public class StandardReflectionParameterNameDiscoverer implements ParameterNameD
 		Parameter[] parameters = ctor.getParameters();
 		String[] parameterNames = new String[parameters.length];
 		for (int i = 0; i < parameters.length; i++) {
-			parameterNames[i] = parameters[i].getName();
+			Parameter param = parameters[i];
+			if (!param.isNamePresent()) {
+				return null;
+			}
+			parameterNames[i] = param.getName();
 		}
 		return parameterNames;
 	}

spring-web/src/main/java/org/springframework/web/method/support/InvocableHandlerMethod.java

@@ -20,8 +20,8 @@ import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.Arrays;
 
+import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.GenericTypeResolver;
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.util.ReflectionUtils;
@@ -51,7 +51,7 @@ public class InvocableHandlerMethod extends HandlerMethod {
 
 	private WebDataBinderFactory dataBinderFactory;
 
-	private ParameterNameDiscoverer parameterNameDiscoverer = new LocalVariableTableParameterNameDiscoverer();
+	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
 
 
 	/**
@@ -97,8 +97,9 @@ public class InvocableHandlerMethod extends HandlerMethod {
 	}
 
 	/**
-	 * Set the ParameterNameDiscoverer for resolving parameter names when needed (e.g. default request attribute name).
-	 * <p>Default is an {@link org.springframework.core.LocalVariableTableParameterNameDiscoverer} instance.
+	 * Set the ParameterNameDiscoverer for resolving parameter names when needed
+	 * (e.g. default request attribute name).
+	 * <p>Default is a {@link org.springframework.core.DefaultParameterNameDiscoverer}.
 	 */
 	public void setParameterNameDiscoverer(ParameterNameDiscoverer parameterNameDiscoverer) {
 		this.parameterNameDiscoverer = parameterNameDiscoverer;

spring-webmvc-portlet/src/main/java/org/springframework/web/portlet/mvc/annotation/AnnotationMethodHandlerAdapter.java

@@ -58,7 +58,7 @@ import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.config.BeanExpressionContext;
 import org.springframework.beans.factory.config.BeanExpressionResolver;
 import org.springframework.beans.factory.config.ConfigurableBeanFactory;
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
+import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.Ordered;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.core.annotation.AnnotationUtils;
@@ -138,7 +138,7 @@ public class AnnotationMethodHandlerAdapter extends PortletContentGenerator
 
 	private boolean synchronizeOnSession = false;
 
-	private ParameterNameDiscoverer parameterNameDiscoverer = new LocalVariableTableParameterNameDiscoverer();
+	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
 
 	private WebArgumentResolver[] customArgumentResolvers;
 
@@ -211,7 +211,7 @@ public class AnnotationMethodHandlerAdapter extends PortletContentGenerator
 	/**
 	 * Set the ParameterNameDiscoverer to use for resolving method parameter
 	 * names if needed (e.g. for default attribute names).
-	 * <p>Default is a {@link org.springframework.core.LocalVariableTableParameterNameDiscoverer}.
+	 * <p>Default is a {@link org.springframework.core.DefaultParameterNameDiscoverer}.
 	 */
 	public void setParameterNameDiscoverer(ParameterNameDiscoverer parameterNameDiscoverer) {
 		this.parameterNameDiscoverer = parameterNameDiscoverer;

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/annotation/AnnotationMethodHandlerAdapter.java

@@ -52,6 +52,7 @@ import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.config.BeanExpressionContext;
 import org.springframework.beans.factory.config.BeanExpressionResolver;
 import org.springframework.beans.factory.config.ConfigurableBeanFactory;
+import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
 import org.springframework.core.Ordered;
 import org.springframework.core.ParameterNameDiscoverer;
@@ -173,7 +174,7 @@ public class AnnotationMethodHandlerAdapter extends WebContentGenerator
 
 	private boolean synchronizeOnSession = false;
 
-	private ParameterNameDiscoverer parameterNameDiscoverer = new LocalVariableTableParameterNameDiscoverer();
+	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
 
 	private WebArgumentResolver[] customArgumentResolvers;
 
@@ -312,7 +313,7 @@ public class AnnotationMethodHandlerAdapter extends WebContentGenerator
 	/**
 	 * Set the ParameterNameDiscoverer to use for resolving method parameter names if needed
 	 * (e.g. for default attribute names).
-	 * <p>Default is a {@link org.springframework.core.LocalVariableTableParameterNameDiscoverer}.
+	 * <p>Default is a {@link org.springframework.core.DefaultParameterNameDiscoverer}.
 	 */
 	public void setParameterNameDiscoverer(ParameterNameDiscoverer parameterNameDiscoverer) {
 		this.parameterNameDiscoverer = parameterNameDiscoverer;

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerAdapter.java

@@ -26,7 +26,6 @@ import java.util.Map.Entry;
 import java.util.Set;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ConcurrentHashMap;
-
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
@@ -36,7 +35,7 @@ import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.config.ConfigurableBeanFactory;
-import org.springframework.core.LocalVariableTableParameterNameDiscoverer;
+import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.OrderComparator;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.core.annotation.AnnotationUtils;
@@ -150,7 +149,7 @@ public class RequestMappingHandlerAdapter extends AbstractHandlerMethodAdapter i
 
 	private SessionAttributeStore sessionAttributeStore = new DefaultSessionAttributeStore();
 
-	private ParameterNameDiscoverer parameterNameDiscoverer = new LocalVariableTableParameterNameDiscoverer();
+	private ParameterNameDiscoverer parameterNameDiscoverer = new DefaultParameterNameDiscoverer();
 
 	private ConfigurableBeanFactory beanFactory;
 
@@ -452,9 +451,9 @@ public class RequestMappingHandlerAdapter extends AbstractHandlerMethodAdapter i
 	}
 
 	/**
-	 * Set the ParameterNameDiscoverer to use for resolving method parameter
-	 * names if needed (e.g. for default attribute names). Default is a
-	 * {@link org.springframework.core.LocalVariableTableParameterNameDiscoverer}.
+	 * Set the ParameterNameDiscoverer to use for resolving method parameter names if needed
+	 * (e.g. for default attribute names).
+	 * <p>Default is a {@link org.springframework.core.DefaultParameterNameDiscoverer}.
 	 */
 	public void setParameterNameDiscoverer(ParameterNameDiscoverer parameterNameDiscoverer) {
 		this.parameterNameDiscoverer = parameterNameDiscoverer;