SpEL support for methods and properties on class …

Update the ReflectiveMethodResolver and ReflectivePropertyAccessor
to allow methods and properties of java.lang.Class to be resolved
when the target object is a class.

Issue: SPR-9017
Backport-Commit: d28592a

Author: philwebb

org.springframework.expression/src/main/java/org/springframework/expression/spel/support/ReflectiveMethodResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -21,8 +21,10 @@
 import java.util.Arrays;
 import java.util.Comparator;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import org.springframework.core.MethodParameter;
 import org.springframework.core.convert.TypeDescriptor;
@@ -90,7 +92,7 @@ public MethodExecutor resolve(EvaluationContext context, Object targetObject, St
 		try {
 			TypeConverter typeConverter = context.getTypeConverter();
 			Class<?> type = (targetObject instanceof Class ? (Class<?>) targetObject : targetObject.getClass());
-			Method[] methods = getMethods(type);
+			Method[] methods = getMethods(type, targetObject);
 
 			// If a filter is registered for this type, call it
 			MethodFilter filter = (this.filters != null ? this.filters.get(type) : null);
@@ -197,6 +199,16 @@ public void registerMethodFilter(Class<?> type, MethodFilter filter) {
 		}
 	}
 
+	private Method[] getMethods(Class<?> type, Object targetObject) {
+		if(targetObject instanceof Class) {
+			Set<Method> methods = new HashSet<Method>();
+			methods.addAll(Arrays.asList(getMethods(type)));
+			methods.addAll(Arrays.asList(getMethods(targetObject.getClass())));
+			return methods.toArray(new Method[methods.size()]);
+		}
+		return getMethods(type);
+	}
+
 	/**
 	 * Return the set of methods for this type. The default implementation returns the
 	 * result of Class#getMethods for the given {@code type}, but subclasses may override

org.springframework.expression/src/main/java/org/springframework/expression/spel/support/ReflectivePropertyAccessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -71,7 +71,7 @@ public boolean canRead(EvaluationContext context, Object target, String name) th
 		if (this.readerCache.containsKey(cacheKey)) {
 			return true;
 		}
-		Method method = findGetterForProperty(name, type, target instanceof Class);
+		Method method = findGetterForProperty(name, type, target);
 		if (method != null) {
 			// Treat it like a property
 			// The readerCache will only contain gettable properties (let's not worry about setters for now)
@@ -82,10 +82,10 @@ public boolean canRead(EvaluationContext context, Object target, String name) th
 			return true;
 		}
 		else {
-			Field field = findField(name, type, target instanceof Class);
+			Field field = findField(name, type, target);
 			if (field != null) {
 				TypeDescriptor typeDescriptor = new TypeDescriptor(field);
-				this.readerCache.put(cacheKey, new InvokerPair(field,typeDescriptor));	
+				this.readerCache.put(cacheKey, new InvokerPair(field,typeDescriptor));
 				this.typeDescriptorCache.put(cacheKey, typeDescriptor);
 				return true;
 			}
@@ -112,7 +112,7 @@ public TypedValue read(EvaluationContext context, Object target, String name) th
 		if (invoker == null || invoker.member instanceof Method) {
 			Method method = (Method) (invoker != null ? invoker.member : null);
 			if (method == null) {
-				method = findGetterForProperty(name, type, target instanceof Class);
+				method = findGetterForProperty(name, type, target);
 				if (method != null) {
 					// TODO remove the duplication here between canRead and read
 					// Treat it like a property
@@ -138,7 +138,7 @@ public TypedValue read(EvaluationContext context, Object target, String name) th
 		if (invoker == null || invoker.member instanceof Field) {
 			Field field = (Field) (invoker == null ? null : invoker.member);
 			if (field == null) {
-				field = findField(name, type, target instanceof Class);
+				field = findField(name, type, target);
 				if (field != null) {
 					invoker = new InvokerPair(field, new TypeDescriptor(field));
 					this.readerCache.put(cacheKey, invoker);
@@ -168,7 +168,7 @@ public boolean canWrite(EvaluationContext context, Object target, String name) t
 		if (this.writerCache.containsKey(cacheKey)) {
 			return true;
 		}
-		Method method = findSetterForProperty(name, type, target instanceof Class);
+		Method method = findSetterForProperty(name, type, target);
 		if (method != null) {
 			// Treat it like a property
 			Property property = new Property(type, null, method);
@@ -178,7 +178,7 @@ public boolean canWrite(EvaluationContext context, Object target, String name) t
 			return true;
 		}
 		else {
-			Field field = findField(name, type, target instanceof Class);
+			Field field = findField(name, type, target);
 			if (field != null) {
 				this.writerCache.put(cacheKey, field);
 				this.typeDescriptorCache.put(cacheKey, new TypeDescriptor(field));
@@ -211,7 +211,7 @@ public void write(EvaluationContext context, Object target, String name, Object
 		if (cachedMember == null || cachedMember instanceof Method) {
 			Method method = (Method) cachedMember;
 			if (method == null) {
-				method = findSetterForProperty(name, type, target instanceof Class);
+				method = findSetterForProperty(name, type, target);
 				if (method != null) {
 					cachedMember = method;
 					this.writerCache.put(cacheKey, cachedMember);
@@ -232,7 +232,7 @@ public void write(EvaluationContext context, Object target, String name, Object
 		if (cachedMember == null || cachedMember instanceof Field) {
 			Field field = (Field) cachedMember;
 			if (field == null) {
-				field = findField(name, type, target instanceof Class);
+				field = findField(name, type, target);
 				if (field != null) {
 					cachedMember = field;
 					this.writerCache.put(cacheKey, cachedMember);
@@ -281,6 +281,30 @@ else if (canWrite(context, target, name)) {
 		return typeDescriptor;
 	}
 
+	private Method findGetterForProperty(String propertyName, Class<?> clazz, Object target) {
+		Method method = findGetterForProperty(propertyName, clazz, target instanceof Class);
+		if(method == null && target instanceof Class) {
+			method = findGetterForProperty(propertyName, target.getClass(), false);
+		}
+		return method;
+	}
+
+	private Method findSetterForProperty(String propertyName, Class<?> clazz, Object target) {
+		Method method = findSetterForProperty(propertyName, clazz, target instanceof Class);
+		if(method == null && target instanceof Class) {
+			method = findSetterForProperty(propertyName, target.getClass(), false);
+		}
+		return method;
+	}
+
+	private Field findField(String name, Class<?> clazz, Object target) {
+		Field field = findField(name, clazz, target instanceof Class);
+		if(field == null && target instanceof Class) {
+			field = findField(name, target.getClass(), false);
+		}
+		return field;
+	}
+
 	/**
 	 * Find a getter method for the specified property. A getter is defined as a method whose name start with the prefix
 	 * 'get' and the rest of the name is the same as the property name (with the first character uppercased).
@@ -404,7 +428,7 @@ public PropertyAccessor createOptimalAccessor(EvaluationContext eContext, Object
 		if (invocationTarget == null || invocationTarget.member instanceof Method) {
 			Method method = (Method) (invocationTarget==null?null:invocationTarget.member);
 			if (method == null) {
-				method = findGetterForProperty(name, type, target instanceof Class);
+				method = findGetterForProperty(name, type, target);
 				if (method != null) {
 					invocationTarget = new InvokerPair(method,new TypeDescriptor(new MethodParameter(method,-1)));
 					ReflectionUtils.makeAccessible(method);

org.springframework.expression/src/test/java/org/springframework/expression/spel/MethodInvocationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -38,6 +38,8 @@
 import org.springframework.expression.spel.support.StandardEvaluationContext;
 import org.springframework.expression.spel.testresources.PlaceOfBirth;
 
+import static org.junit.Assert.*;
+
 /**
  * Tests invocation of methods.
  * 
@@ -361,4 +363,10 @@ public void testInvocationOnNullContextObject() {
 		evaluateAndCheckError("null.toString()",SpelMessage.METHOD_CALL_ON_NULL_OBJECT_NOT_ALLOWED);
 	}
 
+	@Test
+	public void testMethodOfClass() throws Exception {
+		Expression expression = parser.parseExpression("getName()");
+		Object value = expression.getValue(new StandardEvaluationContext(String.class));
+		assertEquals(value, "java.lang.String");
+	}
 }

org.springframework.expression/src/test/java/org/springframework/expression/spel/PropertyAccessTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2009 the original author or authors.
+ * Copyright 2002-2012 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.
@@ -33,6 +33,8 @@
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
 
+import static org.junit.Assert.*;
+
 ///CLOVER:OFF
 
 /**
@@ -155,6 +157,13 @@ public void testAddingRemovingAccessors() {
 		Assert.assertEquals(2,ctx.getPropertyAccessors().size());
 	}
 
+	@Test
+	public void testAccessingPropertyOfClass() throws Exception {
+		Expression expression = parser.parseExpression("name");
+		Object value = expression.getValue(new StandardEvaluationContext(String.class));
+		assertEquals(value, "java.lang.String");
+	}
+
 
 	// This can resolve the property 'flibbles' on any String (very useful...)
 	private static class StringyPropertyAccessor implements PropertyAccessor {