Refactor common methods in in-memory data providers (#9308)

* Refactor common methods of InMemoryHierarchicalDataProvider and ListDataProvider to a single interface
* Rename HierarchyData and InMemoryHierarchicalDataProvider, introduce HasHierarchicalDataProvider
* Additionally adds a helper method for recursive constructing
TreeData with a child item provider.

5 files changed, 54 insertions, 34 deletions

diff --git a/server/src/test/java/com/vaadin/data/provider/InMemoryHierarchicalDataProviderTest.java b/server/src/test/java/com/vaadin/data/provider/TreeDataProviderTest.java
index 99b7a04b19..3f9f1f6e94 100644
--- a/server/src/test/java/com/vaadin/data/provider/InMemoryHierarchicalDataProviderTest.java
+++ b/server/src/test/java/com/vaadin/data/provider/TreeDataProviderTest.java
@@ -1,6 +1,7 @@
 package com.vaadin.data.provider;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Comparator;
 import java.util.List;
 import java.util.stream.Collectors;
@@ -8,13 +9,13 @@ import java.util.stream.Collectors;
 import org.junit.Assert;
 import org.junit.Test;
 
-import com.vaadin.data.HierarchyData;
+import com.vaadin.data.TreeData;
 import com.vaadin.server.SerializablePredicate;
 
-public class InMemoryHierarchicalDataProviderTest extends
-        DataProviderTestBase<InMemoryHierarchicalDataProvider<StrBean>> {
+public class TreeDataProviderTest extends
+        DataProviderTestBase<TreeDataProvider<StrBean>> {
 
-    private HierarchyData<StrBean> data;
+    private TreeData<StrBean> data;
     private List<StrBean> flattenedData;
     private List<StrBean> rootData;
 
@@ -24,7 +25,7 @@ public class InMemoryHierarchicalDataProviderTest extends
         flattenedData = new ArrayList<>();
         rootData = new ArrayList<>();
 
-        data = new HierarchyData<>();
+        data = new TreeData<>();
         data.addItems(null, randomBeans.subList(0, 5));
         data.addItems(randomBeans.get(0), randomBeans.subList(5, 10));
         data.addItems(randomBeans.get(5), randomBeans.subList(10, 15));
@@ -44,42 +45,60 @@ public class InMemoryHierarchicalDataProviderTest extends
     }
 
     @Test(expected = IllegalArgumentException.class)
-    public void hierarchyData_add_item_parent_not_in_hierarchy_throws() {
-        new HierarchyData<>().addItem(new StrBean("", 0, 0),
+    public void treeData_add_item_parent_not_in_hierarchy_throws() {
+        new TreeData<>().addItem(new StrBean("", 0, 0),
                 new StrBean("", 0, 0));
     }
 
     @Test(expected = NullPointerException.class)
-    public void hierarchyData_add_null_item_throws() {
-        new HierarchyData<>().addItem(null, null);
+    public void treeData_add_null_item_throws() {
+        new TreeData<>().addItem(null, null);
     }
 
     @Test(expected = IllegalArgumentException.class)
-    public void hierarchyData_add_item_already_in_hierarchy_throws() {
+    public void treeData_add_item_already_in_hierarchy_throws() {
         StrBean bean = new StrBean("", 0, 0);
-        new HierarchyData<>().addItem(null, bean).addItem(null, bean);
+        new TreeData<>().addItem(null, bean).addItem(null, bean);
     }
 
     @Test
-    public void hierarchyData_remove_root_item() {
+    public void treeData_remove_root_item() {
         data.removeItem(null);
         Assert.assertTrue(data.getChildren(null).isEmpty());
     }
 
     @Test
-    public void hierarchyData_clear() {
+    public void treeData_clear() {
         data.clear();
         Assert.assertTrue(data.getChildren(null).isEmpty());
     }
 
     @Test
-    public void hierarchyData_re_add_removed_item() {
+    public void treeData_re_add_removed_item() {
         StrBean item = rootData.get(0);
         data.removeItem(item).addItem(null, item);
         Assert.assertTrue(data.getChildren(null).contains(item));
     }
 
     @Test
+    public void populate_treeData_with_child_item_provider() {
+        TreeData<String> stringData = new TreeData<>();
+        List<String> rootItems = Arrays.asList("a", "b", "c");
+        stringData.addItems(rootItems, item -> {
+            if (item.length() >= 3 || item.startsWith("c")) {
+                return Arrays.asList();
+            }
+            return Arrays.asList(item + "/a", item + "/b", item + "/c");
+        });
+        Assert.assertEquals(stringData.getChildren("a"),
+                Arrays.asList("a/a", "a/b", "a/c"));
+        Assert.assertEquals(stringData.getChildren("b"),
+                Arrays.asList("b/a", "b/b", "b/c"));
+        Assert.assertEquals(stringData.getChildren("c"), Arrays.asList());
+        Assert.assertEquals(stringData.getChildren("a/b"), Arrays.asList());
+    }
+
+    @Test
     public void setFilter() {
         getDataProvider().setFilter(item -> item.getValue().equals("Xyz")
                 || item.getValue().equals("Baz"));
@@ -226,8 +245,8 @@ public class InMemoryHierarchicalDataProviderTest extends
     }
 
     @Override
-    protected InMemoryHierarchicalDataProvider<StrBean> createDataProvider() {
-        return new InMemoryHierarchicalDataProvider<>(data);
+    protected TreeDataProvider<StrBean> createDataProvider() {
+        return new TreeDataProvider<>(data);
     }
 
     @Override
diff --git a/server/src/test/java/com/vaadin/tests/components/TreeTest.java b/server/src/test/java/com/vaadin/tests/components/TreeTest.java
index 13ef0acc49..9224934a4c 100644
--- a/server/src/test/java/com/vaadin/tests/components/TreeTest.java
+++ b/server/src/test/java/com/vaadin/tests/components/TreeTest.java
@@ -3,8 +3,8 @@ package com.vaadin.tests.components;
 import org.junit.Assert;
 import org.junit.Test;
 
-import com.vaadin.data.HierarchyData;
-import com.vaadin.data.provider.InMemoryHierarchicalDataProvider;
+import com.vaadin.data.TreeData;
+import com.vaadin.data.provider.TreeDataProvider;
 import com.vaadin.event.CollapseEvent;
 import com.vaadin.event.CollapseEvent.CollapseListener;
 import com.vaadin.event.ExpandEvent;
@@ -52,12 +52,12 @@ public class TreeTest {
     @Test
     public void event_source_is_tree() {
         Tree<String> tree = new Tree<>();
-        HierarchyData<String> hierarchyData = new HierarchyData<>();
-        hierarchyData.addItem(null, "Foo");
-        hierarchyData.addItem("Foo", "Bar");
-        hierarchyData.addItem("Foo", "Baz");
+        TreeData<String> treeData = new TreeData<>();
+        treeData.addItem(null, "Foo");
+        treeData.addItem("Foo", "Bar");
+        treeData.addItem("Foo", "Baz");
         tree.setDataProvider(
-                new InMemoryHierarchicalDataProvider<>(hierarchyData));
+                new TreeDataProvider<>(treeData));
 
         TreeCollapseExpandListener listener = new TreeCollapseExpandListener(
                 tree);
diff --git a/server/src/test/java/com/vaadin/tests/components/treegrid/TreeGridTest.java b/server/src/test/java/com/vaadin/tests/components/treegrid/TreeGridTest.java
index 2e335f865e..1544a4f69d 100644
--- a/server/src/test/java/com/vaadin/tests/components/treegrid/TreeGridTest.java
+++ b/server/src/test/java/com/vaadin/tests/components/treegrid/TreeGridTest.java
@@ -3,8 +3,8 @@ package com.vaadin.tests.components.treegrid;
 import org.junit.Assert;
 import org.junit.Test;
 
-import com.vaadin.data.HierarchyData;
-import com.vaadin.data.provider.InMemoryHierarchicalDataProvider;
+import com.vaadin.data.TreeData;
+import com.vaadin.data.provider.TreeDataProvider;
 import com.vaadin.ui.TreeGrid;
 import com.vaadin.ui.renderers.TextRenderer;
 
@@ -24,12 +24,12 @@ public class TreeGridTest {
 
     @Test
     public void testExpandAndCollapseEvents() {
-        HierarchyData<String> hierarchyData = new HierarchyData<>();
-        hierarchyData.addItem(null, "Foo");
-        hierarchyData.addItem("Foo", "Bar");
-        hierarchyData.addItem("Foo", "Baz");
+        TreeData<String> treeData = new TreeData<>();
+        treeData.addItem(null, "Foo");
+        treeData.addItem("Foo", "Bar");
+        treeData.addItem("Foo", "Baz");
         treeGrid.setDataProvider(
-                new InMemoryHierarchicalDataProvider<>(hierarchyData));
+                new TreeDataProvider<>(treeData));
 
         treeGrid.addExpandListener(e -> expandEventFired = true);
         treeGrid.addCollapseListener(e -> collapseEventFired = true);
diff --git a/server/src/test/java/com/vaadin/tests/server/ClassesSerializableTest.java b/server/src/test/java/com/vaadin/tests/server/ClassesSerializableTest.java
index b4f9851867..d2d25b4777 100644
--- a/server/src/test/java/com/vaadin/tests/server/ClassesSerializableTest.java
+++ b/server/src/test/java/com/vaadin/tests/server/ClassesSerializableTest.java
@@ -76,6 +76,7 @@ public class ClassesSerializableTest {
             "com\\.vaadin\\.buildhelpers.*", //
             "com\\.vaadin\\.util\\.EncodeUtil.*", //
             "com\\.vaadin\\.util\\.ReflectTools.*", //
+            "com\\.vaadin\\.data\\.provider\\.InMemoryDataProviderHelpers",
             "com\\.vaadin\\.data\\.provider\\.HierarchyMapper\\$TreeLevelQuery",
             "com\\.vaadin\\.data\\.util\\.ReflectTools.*", //
             "com\\.vaadin\\.data\\.util\\.JsonUtil.*", //
diff --git a/server/src/test/java/com/vaadin/tests/server/component/treegrid/TreeGridDeclarativeTest.java b/server/src/test/java/com/vaadin/tests/server/component/treegrid/TreeGridDeclarativeTest.java
index c8a51a1928..a13ba357ef 100644
--- a/server/src/test/java/com/vaadin/tests/server/component/treegrid/TreeGridDeclarativeTest.java
+++ b/server/src/test/java/com/vaadin/tests/server/component/treegrid/TreeGridDeclarativeTest.java
@@ -4,9 +4,9 @@ import java.lang.reflect.InvocationTargetException;
 
 import org.junit.Assert;
 
-import com.vaadin.data.HierarchyData;
+import com.vaadin.data.TreeData;
 import com.vaadin.data.provider.HierarchicalQuery;
-import com.vaadin.data.provider.InMemoryHierarchicalDataProvider;
+import com.vaadin.data.provider.TreeDataProvider;
 import com.vaadin.tests.data.bean.Person;
 import com.vaadin.tests.server.component.abstractlisting.AbstractListingDeclarativeTest;
 import com.vaadin.ui.TreeGrid;
@@ -28,7 +28,7 @@ public class TreeGridDeclarativeTest
         Person person6 = createPerson("ca", "last-name");
         Person person7 = createPerson("caa", "last-name");
 
-        HierarchyData<Person> data = new HierarchyData<>();
+        TreeData<Person> data = new TreeData<>();
         data.addItems(null, person1, person4, person5);
         data.addItems(person1, person2, person3);
         data.addItem(person5, person6);
@@ -38,7 +38,7 @@ public class TreeGridDeclarativeTest
         grid.addColumn(Person::getLastName).setId("id").setCaption("Id");
 
         grid.setHierarchyColumn("id");
-        grid.setDataProvider(new InMemoryHierarchicalDataProvider<>(data));
+        grid.setDataProvider(new TreeDataProvider<>(data));
 
         String design = String.format(
                 "<%s hierarchy-column='id'><table><colgroup>"