Allow BeanFieldGroup.setItemDataSource() method accept null (#14731).

Change-Id: I7a451f428f0aa3ea7fc322cac6b0e62d830d7987

3 files changed, 35 insertions, 7 deletions

diff --git a/server/src/com/vaadin/data/fieldgroup/BeanFieldGroup.java b/server/src/com/vaadin/data/fieldgroup/BeanFieldGroup.java
index e5d53b759d..1f3ee36d58 100644
--- a/server/src/com/vaadin/data/fieldgroup/BeanFieldGroup.java
+++ b/server/src/com/vaadin/data/fieldgroup/BeanFieldGroup.java
@@ -130,16 +130,17 @@ public class BeanFieldGroup<T> extends FieldGroup {
      *            The bean to use as data source.
      */
     public void setItemDataSource(T bean) {
-        setItemDataSource(new BeanItem(bean));
+        setItemDataSource(new BeanItem<T>(bean, beanType));
     }
 
     @Override
     public void setItemDataSource(Item item) {
-        if (!(item instanceof BeanItem)) {
+        if (item == null || (item instanceof BeanItem)) {
+            super.setItemDataSource(item);
+        } else {
             throw new RuntimeException(getClass().getSimpleName()
                     + " only supports BeanItems as item data source");
         }
-        super.setItemDataSource(item);
     }
 
     @Override
diff --git a/server/src/com/vaadin/data/util/BeanItem.java b/server/src/com/vaadin/data/util/BeanItem.java
index 12d9b23d0a..64f30261c2 100644
--- a/server/src/com/vaadin/data/util/BeanItem.java
+++ b/server/src/com/vaadin/data/util/BeanItem.java
@@ -62,7 +62,30 @@ public class BeanItem<BT> extends PropertysetItem {
      * 
      */
     public BeanItem(BT bean) {
-        this(bean, getPropertyDescriptors((Class<BT>) bean.getClass()));
+        this(bean, (Class<BT>) bean.getClass());
+    }
+
+    /**
+     * <p>
+     * Creates a new instance of <code>BeanItem</code> and adds all properties
+     * of a Java Bean to it. The properties are identified by their respective
+     * bean names.
+     * </p>
+     * 
+     * <p>
+     * Note : This version only supports introspectable bean properties and
+     * their getter and setter methods. Stand-alone <code>is</code> and
+     * <code>are</code> methods are not supported.
+     * </p>
+     * 
+     * @param bean
+     *            the Java Bean to copy properties from.
+     * @param beanClass
+     *            class of the {@code bean}
+     * 
+     */
+    public BeanItem(BT bean, Class<BT> beanClass) {
+        this(bean, getPropertyDescriptors(beanClass));
     }
 
     /**
diff --git a/server/src/com/vaadin/data/util/MethodProperty.java b/server/src/com/vaadin/data/util/MethodProperty.java
index 5e6b731571..853f68b711 100644
--- a/server/src/com/vaadin/data/util/MethodProperty.java
+++ b/server/src/com/vaadin/data/util/MethodProperty.java
@@ -132,7 +132,7 @@ public class MethodProperty<T> extends AbstractProperty<T> {
             setArguments(getArgs, setArgs, setArgumentIndex);
             String name = (String) in.readObject();
             Class<?>[] paramTypes = SerializerHelper.readClassArray(in);
-            if (name != null) {
+            if (instance != null && name != null) {
                 setMethod = instance.getClass().getMethod(name, paramTypes);
             } else {
                 setMethod = null;
@@ -140,7 +140,7 @@ public class MethodProperty<T> extends AbstractProperty<T> {
 
             name = (String) in.readObject();
             paramTypes = SerializerHelper.readClassArray(in);
-            if (name != null) {
+            if (instance != null && name != null) {
                 getMethod = instance.getClass().getMethod(name, paramTypes);
             } else {
                 getMethod = null;
@@ -589,7 +589,11 @@ public class MethodProperty<T> extends AbstractProperty<T> {
     @Override
     public T getValue() {
         try {
-            return (T) getMethod.invoke(instance, getArgs);
+            if (instance == null) {
+                return null;
+            } else {
+                return (T) getMethod.invoke(instance, getArgs);
+            }
         } catch (final Throwable e) {
             throw new MethodException(this, e);
         }