Add method to get parent in TreeData (#9701)

2 files changed, 27 insertions, 0 deletions

diff --git a/server/src/main/java/com/vaadin/data/TreeData.java b/server/src/main/java/com/vaadin/data/TreeData.java
index bebf312614..1a5b0e4d3a 100644
--- a/server/src/main/java/com/vaadin/data/TreeData.java
+++ b/server/src/main/java/com/vaadin/data/TreeData.java
@@ -368,6 +368,25 @@ public class TreeData<T> implements Serializable {
     }
 
     /**
+     * Get the parent item for the given item.
+     *
+     * @param item
+     *         the item for which to retrieve the parent item for
+     * @return parent item for the given item or {@code null} if the item is a
+     *         root item.
+     * @throws IllegalArgumentException
+     *         if the item does not exist in this structure
+     * @since 8.1.1
+     */
+    public T getParent(T item) {
+        if (!contains(item)) {
+            throw new IllegalArgumentException(
+                    "Item '" + item + "' not in hierarchy");
+        }
+        return itemToWrapperMap.get(item).getParent();
+    }
+
+    /**
      * Moves an item to become a child of the given parent item. The new parent
      * item must exist in the hierarchy. Setting the parent to {@code null}
      * makes the item a root item. After making changes to the tree data, {@link
diff --git a/server/src/test/java/com/vaadin/data/provider/TreeDataProviderTest.java b/server/src/test/java/com/vaadin/data/provider/TreeDataProviderTest.java
index 8232d2fc45..3ff94e9988 100644
--- a/server/src/test/java/com/vaadin/data/provider/TreeDataProviderTest.java
+++ b/server/src/test/java/com/vaadin/data/provider/TreeDataProviderTest.java
@@ -81,6 +81,14 @@ public class TreeDataProviderTest
     }
 
     @Test
+    public void treeData_get_parent() {
+        StrBean root = rootData.get(0);
+        StrBean firstChild = data.getChildren(root).get(0);
+        Assert.assertNull(data.getParent(root));
+        Assert.assertEquals(root, data.getParent(firstChild));
+    }
+
+    @Test
     public void treeData_set_parent() {
         StrBean item1 = rootData.get(0);
         StrBean item2 = rootData.get(1);