From bb97ca32c460ed1763384edba57cf615b3bb193c Mon Sep 17 00:00:00 2001
From: Juergen Hoeller <jhoeller@vmware.com>
Date: Wed, 25 Nov 2009 00:17:29 +0000
Subject: [PATCH] added configurable "autoGrowNestedPaths" property to
 DataBinder (SPR-6430)

---
 .../springframework/beans/BeanWrapper.java    |  8 +++----
 .../validation/BeanPropertyBindingResult.java | 15 +++++++++++-
 .../validation/DataBinder.java                | 23 ++++++++++++++++++-
 3 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/org.springframework.beans/src/main/java/org/springframework/beans/BeanWrapper.java b/org.springframework.beans/src/main/java/org/springframework/beans/BeanWrapper.java
index 3a4a26ec19..3469d8506a 100644
--- a/org.springframework.beans/src/main/java/org/springframework/beans/BeanWrapper.java
+++ b/org.springframework.beans/src/main/java/org/springframework/beans/BeanWrapper.java
@@ -79,11 +79,11 @@ public interface BeanWrapper extends ConfigurablePropertyAccessor {
 	PropertyDescriptor getPropertyDescriptor(String propertyName) throws InvalidPropertyException;
 
 	/**
-	 * Set if this BeanWrapper should attempt to "auto-grow" a nested path that contains a null value.
-	 * <p>If true, a null path location will be populated with a default object value and traversed
+	 * Set whether this BeanWrapper should attempt to "auto-grow" a nested path that contains a null value.
+	 * <p>If "true", a null path location will be populated with a default object value and traversed
 	 * instead of resulting in a {@link NullValueInNestedPathException}. Turning this flag on also
-	 * enables auto-growth of collection elements when an index that is out of bounds is accessed.
-	 * <p>Default is false.
+	 * enables auto-growth of collection elements when accessing an out-of-bounds index.
+	 * <p>Default is "false" on a plain BeanWrapper.
 	 */
 	void setAutoGrowNestedPaths(boolean autoGrowNestedPaths);
 
diff --git a/org.springframework.context/src/main/java/org/springframework/validation/BeanPropertyBindingResult.java b/org.springframework.context/src/main/java/org/springframework/validation/BeanPropertyBindingResult.java
index 0f77384f4e..3437e672b9 100644
--- a/org.springframework.context/src/main/java/org/springframework/validation/BeanPropertyBindingResult.java
+++ b/org.springframework.context/src/main/java/org/springframework/validation/BeanPropertyBindingResult.java
@@ -44,6 +44,8 @@ public class BeanPropertyBindingResult extends AbstractPropertyBindingResult imp
 
 	private final Object target;
 
+	private final boolean autoGrowNestedPaths;
+
 	private transient BeanWrapper beanWrapper;
 
 
@@ -53,8 +55,19 @@ public class BeanPropertyBindingResult extends AbstractPropertyBindingResult imp
 	 * @param objectName the name of the target object
 	 */
 	public BeanPropertyBindingResult(Object target, String objectName) {
+		this(target, objectName, true);
+	}
+
+	/**
+	 * Creates a new instance of the {@link BeanPropertyBindingResult} class.
+	 * @param target the target bean to bind onto
+	 * @param objectName the name of the target object
+	 * @param autoGrowNestedPaths whether to "auto-grow" a nested path that contains a null value
+	 */
+	public BeanPropertyBindingResult(Object target, String objectName, boolean autoGrowNestedPaths) {
 		super(objectName);
 		this.target = target;
+		this.autoGrowNestedPaths = autoGrowNestedPaths;
 	}
 
 
@@ -73,7 +86,7 @@ public class BeanPropertyBindingResult extends AbstractPropertyBindingResult imp
 		if (this.beanWrapper == null) {
 			this.beanWrapper = createBeanWrapper();
 			this.beanWrapper.setExtractOldValueForEditor(true);
-			this.beanWrapper.setAutoGrowNestedPaths(true);
+			this.beanWrapper.setAutoGrowNestedPaths(this.autoGrowNestedPaths);
 		}
 		return this.beanWrapper;
 	}
diff --git a/org.springframework.context/src/main/java/org/springframework/validation/DataBinder.java b/org.springframework.context/src/main/java/org/springframework/validation/DataBinder.java
index 6ee866ae28..b5d13ef184 100644
--- a/org.springframework.context/src/main/java/org/springframework/validation/DataBinder.java
+++ b/org.springframework.context/src/main/java/org/springframework/validation/DataBinder.java
@@ -125,6 +125,8 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 
 	private boolean ignoreInvalidFields = false;
 
+	private boolean autoGrowNestedPaths = true;
+
 	private String[] allowedFields;
 
 	private String[] disallowedFields;
@@ -182,7 +184,7 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	public void initBeanPropertyAccess() {
 		Assert.isNull(this.bindingResult,
 				"DataBinder is already initialized - call initBeanPropertyAccess before any other configuration methods");
-		this.bindingResult = new BeanPropertyBindingResult(getTarget(), getObjectName());
+		this.bindingResult = new BeanPropertyBindingResult(getTarget(), getObjectName(), isAutoGrowNestedPaths());
 		if (this.conversionService != null) {
 			this.bindingResult.initConversion(this.conversionService);
 		}
@@ -330,6 +332,25 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 		return this.ignoreInvalidFields;
 	}
 
+	/**
+	 * Set whether this binder should attempt to "auto-grow" a nested path that contains a null value.
+	 * <p>If "true", a null path location will be populated with a default object value and traversed
+	 * instead of resulting in an exception. This flag also enables auto-growth of collection elements
+	 * when accessing an out-of-bounds index.
+	 * <p>Default is "true" on a standard DataBinder.
+	 * @see org.springframework.beans.BeanWrapper#setAutoGrowNestedPaths
+	 */
+	public void setAutoGrowNestedPaths(boolean autoGrowNestedPaths) {
+		this.autoGrowNestedPaths = autoGrowNestedPaths;
+	}
+
+	/**
+	 * Return whether "auto-growing" of nested paths has been activated.
+	 */
+	public boolean isAutoGrowNestedPaths() {
+		return this.autoGrowNestedPaths;
+	}
+
 	/**
 	 * Register fields that should be allowed for binding. Default is all
 	 * fields. Restrict this for example to avoid unwanted modifications