Backported null value support for NestedMethodProperty to 7.1 (#12884)

Support for null values in NestedMethodProperty was already implemented in master branch (#11435)
This changeset includes changesets made for that.

Change-Id: I10696467f792e234326075bbcdd5aad487905a7e
Merge: no

3 files changed, 19 insertions, 10 deletions

diff --git a/server/src/com/vaadin/data/util/AbstractBeanContainer.java b/server/src/com/vaadin/data/util/AbstractBeanContainer.java
index 35403d6419..b19cdd980c 100644
--- a/server/src/com/vaadin/data/util/AbstractBeanContainer.java
+++ b/server/src/com/vaadin/data/util/AbstractBeanContainer.java
@@ -836,8 +836,9 @@ public abstract class AbstractBeanContainer<IDTYPE, BEANTYPE> extends
      * Adds a nested container property for the container, e.g.
      * "manager.address.street".
      * 
-     * All intermediate getters must exist and must return non-null values when
-     * the property value is accessed.
+     * All intermediate getters must exist and should return non-null values
+     * when the property value is accessed. If an intermediate getter returns
+     * null, a null value will be returned.
      * 
      * @see NestedMethodProperty
      * 
@@ -854,8 +855,9 @@ public abstract class AbstractBeanContainer<IDTYPE, BEANTYPE> extends
      * property to the container. The named property itself is removed from the
      * model as its subproperties are added.
      * 
-     * All intermediate getters must exist and must return non-null values when
-     * the property value is accessed.
+     * All intermediate getters must exist and should return non-null values
+     * when the property value is accessed. If an intermediate getter returns
+     * null, a null value will be returned.
      * 
      * @see NestedMethodProperty
      * @see #addNestedContainerProperty(String)
diff --git a/server/src/com/vaadin/data/util/BeanItem.java b/server/src/com/vaadin/data/util/BeanItem.java
index fc51be8f36..49f5f95898 100644
--- a/server/src/com/vaadin/data/util/BeanItem.java
+++ b/server/src/com/vaadin/data/util/BeanItem.java
@@ -255,12 +255,13 @@ public class BeanItem<BT> extends PropertysetItem {
     }
 
     /**
-     * Adds a nested property to the item.
+     * Adds a nested property to the item. The property must not exist in the
+     * item already and must of form "field1.field2" where field2 is a field in
+     * the object referenced to by field1. If an intermediate property returns
+     * null, the property will return a null value
      * 
      * @param nestedPropertyId
-     *            property id to add. This property must not exist in the item
-     *            already and must of of form "field1.field2" where field2 is a
-     *            field in the object referenced to by field1
+     *            property id to add.
      */
     public void addNestedProperty(String nestedPropertyId) {
         addItemProperty(nestedPropertyId, new NestedMethodProperty<Object>(
diff --git a/server/src/com/vaadin/data/util/NestedMethodProperty.java b/server/src/com/vaadin/data/util/NestedMethodProperty.java
index b62ecfbfc3..8fe3b9d4c5 100644
--- a/server/src/com/vaadin/data/util/NestedMethodProperty.java
+++ b/server/src/com/vaadin/data/util/NestedMethodProperty.java
@@ -31,8 +31,9 @@ import com.vaadin.data.util.MethodProperty.MethodException;
  * The property is specified in the dotted notation, e.g. "address.street", and
  * can contain multiple levels of nesting.
  * 
- * When accessing the property value, all intermediate getters must return
- * non-null values.
+ * When accessing the property value, all intermediate getters must exist and
+ * should return non-null values when the property value is accessed. If an
+ * intermediate getter returns null, a null value will be returned.
  * 
  * @see MethodProperty
  * 
@@ -76,6 +77,8 @@ public class NestedMethodProperty<T> extends AbstractProperty<T> {
      * Constructs a nested method property for a given object instance. The
      * property name is a dot separated string pointing to a nested property,
      * e.g. "manager.address.street".
+     * <p>
+     * Calling getValue will return null if any intermediate getter returns null
      * 
      * @param instance
      *            top-level bean to which the property applies
@@ -199,6 +202,9 @@ public class NestedMethodProperty<T> extends AbstractProperty<T> {
             Object object = instance;
             for (Method m : getMethods) {
                 object = m.invoke(object);
+                if (object == null) {
+                    return null;
+                }
             }
             return (T) object;
         } catch (final Throwable e) {