BeanWrapper auto-growing support for EnumSet / EnumMap

Issue: SPR-12483

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

@@ -613,16 +613,17 @@ public class BeanWrapperImpl extends AbstractPropertyAccessor implements BeanWra
 	}
 
 	private PropertyValue createDefaultPropertyValue(PropertyTokenHolder tokens) {
-		Class<?> type = getPropertyTypeDescriptor(tokens.canonicalName).getType();
+		TypeDescriptor desc = getPropertyTypeDescriptor(tokens.canonicalName);
+		Class<?> type = desc.getType();
 		if (type == null) {
 			throw new NullValueInNestedPathException(getRootClass(), this.nestedPath + tokens.canonicalName,
 					"Could not determine property type for auto-growing a default value");
 		}
-		Object defaultValue = newValue(type, tokens.canonicalName);
+		Object defaultValue = newValue(type, desc, tokens.canonicalName);
 		return new PropertyValue(tokens.canonicalName, defaultValue);
 	}
 
-	private Object newValue(Class<?> type, String name) {
+	private Object newValue(Class<?> type, TypeDescriptor desc, String name) {
 		try {
 			if (type.isArray()) {
 				Class<?> componentType = type.getComponentType();
@@ -637,17 +638,20 @@ public class BeanWrapperImpl extends AbstractPropertyAccessor implements BeanWra
 				}
 			}
 			else if (Collection.class.isAssignableFrom(type)) {
-				return CollectionFactory.createCollection(type, 16);
+				TypeDescriptor elementDesc = (desc != null ? desc.getElementTypeDescriptor() : null);
+				return CollectionFactory.createCollection(type, (elementDesc != null ? elementDesc.getType() : null), 16);
 			}
 			else if (Map.class.isAssignableFrom(type)) {
-				return CollectionFactory.createMap(type, 16);
+				TypeDescriptor keyDesc = (desc != null ? desc.getMapKeyTypeDescriptor() : null);
+				return CollectionFactory.createMap(type, (keyDesc != null ? keyDesc.getType() : null), 16);
 			}
 			else {
 				return type.newInstance();
 			}
 		}
 		catch (Exception ex) {
-			// TODO Root cause exception context is lost here... should we throw another exception type that preserves context instead?
+			// TODO: Root cause exception context is lost here; just exception message preserved.
+			// Should we throw another exception type that preserves context instead?
 			throw new NullValueInNestedPathException(getRootClass(), this.nestedPath + name,
 					"Could not instantiate property type [" + type.getName() + "] to auto-grow nested property path: " + ex);
 		}
@@ -860,7 +864,7 @@ public class BeanWrapperImpl extends AbstractPropertyAccessor implements BeanWra
 			Object newArray = Array.newInstance(componentType, index + 1);
 			System.arraycopy(array, 0, newArray, 0, length);
 			for (int i = length; i < Array.getLength(newArray); i++) {
-				Array.set(newArray, i, newValue(componentType, name));
+				Array.set(newArray, i, newValue(componentType, null, name));
 			}
 			// TODO this is not efficient because conversion may create a copy ... set directly because we know it is assignable.
 			setPropertyValue(name, newArray);
@@ -882,7 +886,7 @@ public class BeanWrapperImpl extends AbstractPropertyAccessor implements BeanWra
 			Class<?> elementType = GenericCollectionTypeResolver.getCollectionReturnType(pd.getReadMethod(), nestingLevel);
 			if (elementType != null) {
 				for (int i = collection.size(); i < index + 1; i++) {
-					collection.add(newValue(elementType, name));
+					collection.add(newValue(elementType, null, name));
 				}
 			}
 		}

spring-beans/src/test/java/org/springframework/beans/BeanWrapperEnumTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -16,8 +16,12 @@
 
 package org.springframework.beans;
 
+import java.util.LinkedHashMap;
+import java.util.Map;
+
 import org.junit.Test;
 
+import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.tests.sample.beans.CustomEnum;
 import org.springframework.tests.sample.beans.GenericBean;
 
@@ -121,4 +125,52 @@ public final class BeanWrapperEnumTests {
 		assertTrue(gb.getCustomEnumSet().contains(CustomEnum.VALUE_2));
 	}
 
+	@Test
+	public void testStandardEnumSetWithMultipleValues() {
+		GenericBean<?> gb = new GenericBean<Object>();
+		BeanWrapper bw = new BeanWrapperImpl(gb);
+		bw.setConversionService(new DefaultConversionService());
+		assertNull(gb.getStandardEnumSet());
+		bw.setPropertyValue("standardEnumSet", new String[] {"VALUE_1", "VALUE_2"});
+		assertEquals(2, gb.getStandardEnumSet().size());
+		assertTrue(gb.getStandardEnumSet().contains(CustomEnum.VALUE_1));
+		assertTrue(gb.getStandardEnumSet().contains(CustomEnum.VALUE_2));
+	}
+
+	@Test
+	public void testStandardEnumSetWithAutoGrowing() {
+		GenericBean<?> gb = new GenericBean<Object>();
+		BeanWrapper bw = new BeanWrapperImpl(gb);
+		bw.setAutoGrowNestedPaths(true);
+		assertNull(gb.getStandardEnumSet());
+		bw.getPropertyValue("standardEnumSet.class");
+		assertEquals(0, gb.getStandardEnumSet().size());
+	}
+
+	@Test
+	public void testStandardEnumMapWithMultipleValues() {
+		GenericBean<?> gb = new GenericBean<Object>();
+		BeanWrapper bw = new BeanWrapperImpl(gb);
+		bw.setConversionService(new DefaultConversionService());
+		assertNull(gb.getStandardEnumMap());
+		Map<String, Integer> map = new LinkedHashMap<String, Integer>();
+		map.put("VALUE_1", 1);
+		map.put("VALUE_2", 2);
+		bw.setPropertyValue("standardEnumMap", map);
+		assertEquals(2, gb.getStandardEnumMap().size());
+		assertEquals(new Integer(1), gb.getStandardEnumMap().get(CustomEnum.VALUE_1));
+		assertEquals(new Integer(2), gb.getStandardEnumMap().get(CustomEnum.VALUE_2));
+	}
+
+	@Test
+	public void testStandardEnumMapWithAutoGrowing() {
+		GenericBean<?> gb = new GenericBean<Object>();
+		BeanWrapper bw = new BeanWrapperImpl(gb);
+		bw.setAutoGrowNestedPaths(true);
+		assertNull(gb.getStandardEnumMap());
+		bw.setPropertyValue("standardEnumMap[VALUE_1]", 1);
+		assertEquals(1, gb.getStandardEnumMap().size());
+		assertEquals(new Integer(1), gb.getStandardEnumMap().get(CustomEnum.VALUE_1));
+	}
+
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2010 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -19,6 +19,8 @@ package org.springframework.tests.sample.beans;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.EnumMap;
+import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -67,6 +69,10 @@ public class GenericBean<T> {
 
 	private Set<CustomEnum> customEnumSet;
 
+	private EnumSet<CustomEnum> standardEnumSet;
+
+	private EnumMap<CustomEnum, Integer> standardEnumMap;
+
 	private T genericProperty;
 
 	private List<T> genericListProperty;
@@ -267,6 +273,22 @@ public class GenericBean<T> {
 		}
 	}
 
+	public EnumSet<CustomEnum> getStandardEnumSet() {
+		return standardEnumSet;
+	}
+
+	public void setStandardEnumSet(EnumSet<CustomEnum> standardEnumSet) {
+		this.standardEnumSet = standardEnumSet;
+	}
+
+	public EnumMap<CustomEnum, Integer> getStandardEnumMap() {
+		return standardEnumMap;
+	}
+
+	public void setStandardEnumMap(EnumMap<CustomEnum, Integer> standardEnumMap) {
+		this.standardEnumMap = standardEnumMap;
+	}
+
 	public static GenericBean createInstance(Set<Integer> integerSet) {
 		return new GenericBean(integerSet);
 	}

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

@@ -140,8 +140,10 @@ public abstract class CollectionFactory {
 	 * Create the most appropriate collection for the given collection type.
 	 * @param collectionClass the desired type of the target Collection
 	 * @param elementType the collection's element type, or {@code null} if not known
+	 * (note: only relevant for {@link EnumSet} creation)
 	 * @param capacity the initial capacity
 	 * @return the new Collection instance
+	 * @since 4.1.3
 	 * @see java.util.LinkedHashSet
 	 * @see java.util.TreeSet
 	 * @see java.util.EnumSet
@@ -229,8 +231,10 @@ public abstract class CollectionFactory {
 	 * Create the most approximate map for the given map.
 	 * @param mapClass the desired type of the target Map
 	 * @param keyType the map's key type, or {@code null} if not known
+	 * (note: only relevant for {@link EnumMap} creation)
 	 * @param capacity the initial capacity
 	 * @return the new Map instance
+	 * @since 4.1.3
 	 * @see java.util.LinkedHashMap
 	 * @see java.util.TreeMap
 	 * @see java.util.EnumMap