Convert comma-separated string into list of classes analogous to existing support for class array

Issue: SPR-14415

Author: jhoeller

spring-beans/src/main/java/org/springframework/beans/TypeConverterDelegate.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -183,10 +183,14 @@ public <T> T convertIfNecessary(String propertyName, Object oldValue, Object new
 
 		// Value not of required type?
 		if (editor != null || (requiredType != null && !ClassUtils.isAssignableValue(requiredType, convertedValue))) {
-			if (requiredType != null && Collection.class.isAssignableFrom(requiredType) && convertedValue instanceof String) {
-				TypeDescriptor elementType = typeDescriptor.getElementTypeDescriptor();
-				if (elementType != null && Enum.class.isAssignableFrom(elementType.getType())) {
-					convertedValue = StringUtils.commaDelimitedListToStringArray((String) convertedValue);
+			if (typeDescriptor != null && requiredType != null && Collection.class.isAssignableFrom(requiredType) &&
+					convertedValue instanceof String) {
+				TypeDescriptor elementTypeDesc = typeDescriptor.getElementTypeDescriptor();
+				if (elementTypeDesc != null) {
+					Class<?> elementType = elementTypeDesc.getType();
+					if (Class.class == elementType || Enum.class.isAssignableFrom(elementType)) {
+						convertedValue = StringUtils.commaDelimitedListToStringArray((String) convertedValue);
+					}
 				}
 			}
 			if (editor == null) {

spring-beans/src/test/java/org/springframework/beans/factory/xml/XmlBeanCollectionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -29,6 +29,7 @@
 import java.util.TreeMap;
 import java.util.TreeSet;
 
+import org.junit.Before;
 import org.junit.Test;
 
 import org.springframework.beans.factory.BeanCreationException;
@@ -52,14 +53,16 @@
  */
 public class XmlBeanCollectionTests {
 
-	private final DefaultListableBeanFactory beanFactory;
+	private final DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
 
-	public XmlBeanCollectionTests() {
-		this.beanFactory = new DefaultListableBeanFactory();
+
+	@Before
+	public void loadBeans() {
 		new XmlBeanDefinitionReader(this.beanFactory).loadBeanDefinitions(
 				new ClassPathResource("collections.xml", getClass()));
 	}
 
+
 	@Test
 	public void testCollectionFactoryDefaults() throws Exception {
 		ListFactoryBean listFactory = new ListFactoryBean();
@@ -327,6 +330,15 @@ public void testObjectArray() throws Exception {
 		assertTrue(hasMap.getObjectArray()[1].equals(this.beanFactory.getBean("jenny")));
 	}
 
+	@Test
+	public void testIntegerArray() throws Exception {
+		HasMap hasMap = (HasMap) this.beanFactory.getBean("integerArray");
+		assertTrue(hasMap.getIntegerArray().length == 3);
+		assertTrue(hasMap.getIntegerArray()[0].intValue() == 0);
+		assertTrue(hasMap.getIntegerArray()[1].intValue() == 1);
+		assertTrue(hasMap.getIntegerArray()[2].intValue() == 2);
+	}
+
 	@Test
 	public void testClassArray() throws Exception {
 		HasMap hasMap = (HasMap) this.beanFactory.getBean("classArray");
@@ -336,12 +348,11 @@ public void testClassArray() throws Exception {
 	}
 
 	@Test
-	public void testIntegerArray() throws Exception {
-		HasMap hasMap = (HasMap) this.beanFactory.getBean("integerArray");
-		assertTrue(hasMap.getIntegerArray().length == 3);
-		assertTrue(hasMap.getIntegerArray()[0].intValue() == 0);
-		assertTrue(hasMap.getIntegerArray()[1].intValue() == 1);
-		assertTrue(hasMap.getIntegerArray()[2].intValue() == 2);
+	public void testClassList() throws Exception {
+		HasMap hasMap = (HasMap) this.beanFactory.getBean("classList");
+		assertTrue(hasMap.getClassList().size()== 2);
+		assertTrue(hasMap.getClassList().get(0).equals(String.class));
+		assertTrue(hasMap.getClassList().get(1).equals(Exception.class));
 	}
 
 	@Test
@@ -447,4 +458,5 @@ public Object getObject() {
 			return obj;
 		}
 	}
+
 }

spring-beans/src/test/java/org/springframework/tests/sample/beans/HasMap.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -17,6 +17,7 @@
 package org.springframework.tests.sample.beans;
 
 import java.util.IdentityHashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 import java.util.Set;
@@ -38,9 +39,11 @@ public class HasMap {
 
 	private Object[] objectArray;
 
+	private Integer[] intArray;
+
 	private Class<?>[] classArray;
 
-	private Integer[] intArray;
+	private List<Class<?>> classList;
 
 	private IdentityHashMap identityMap;
 
@@ -81,6 +84,14 @@ public void setObjectArray(Object[] objectArray) {
 		this.objectArray = objectArray;
 	}
 
+	public Integer[] getIntegerArray() {
+		return intArray;
+	}
+
+	public void setIntegerArray(Integer[] is) {
+		intArray = is;
+	}
+
 	public Class<?>[] getClassArray() {
 		return classArray;
 	}
@@ -89,12 +100,12 @@ public void setClassArray(Class<?>[] classArray) {
 		this.classArray = classArray;
 	}
 
-	public Integer[] getIntegerArray() {
-		return intArray;
+	public List<Class<?>> getClassList() {
+		return classList;
 	}
 
-	public void setIntegerArray(Integer[] is) {
-		intArray = is;
+	public void setClassList(List<Class<?>> classList) {
+		this.classList = classList;
 	}
 
 	public IdentityHashMap getIdentityMap() {

spring-beans/src/test/resources/org/springframework/beans/factory/xml/collections.xml

@@ -288,15 +288,6 @@
 		</property>
 	</bean>
 
-	<bean id="classArray" class="org.springframework.tests.sample.beans.HasMap">
-		<property name="classArray">
-			<list>
-				<value>java.lang.String</value>
-				<value>java.lang.Exception</value>
-			</list>
-		</property>
-	</bean>
-
 	<bean id="integerArray" class="org.springframework.tests.sample.beans.HasMap">
 		<property name="integerArray">
 			<list>
@@ -307,6 +298,14 @@
 		</property>
 	</bean>
 
+	<bean id="classArray" class="org.springframework.tests.sample.beans.HasMap">
+		<property name="classArray" value="java.lang.String,java.lang.Exception"/>
+	</bean>
+
+	<bean id="classList" class="org.springframework.tests.sample.beans.HasMap">
+		<property name="classList" value="java.lang.String,java.lang.Exception"/>
+	</bean>
+
 	<bean id="listFactory" class="org.springframework.beans.factory.config.ListFactoryBean">
 		<property name="sourceList">
 			<list>

spring-core/src/main/java/org/springframework/core/convert/TypeDescriptor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -145,10 +145,9 @@ public Class<?> getObjectType() {
 	/**
 	 * The type of the backing class, method parameter, field, or property
 	 * described by this TypeDescriptor.
-	 * <p>Returns primitive types as-is.
-	 * <p>See {@link #getObjectType()} for a variation of this operation that
-	 * resolves primitive types to their corresponding Object types if necessary.
-	 * @return the type, or {@code null} if it cannot be determined
+	 * <p>Returns primitive types as-is. See {@link #getObjectType()} for a
+	 * variation of this operation that resolves primitive types to their
+	 * corresponding Object types if necessary.
 	 * @see #getObjectType()
 	 */
 	public Class<?> getType() {