Clarify TreeData and TreeDataProvider javadocs, improve documentation (#9349)

2 files changed, 9 insertions, 22 deletions

diff --git a/documentation/components/components-treegrid.asciidoc b/documentation/components/components-treegrid.asciidoc
index 7f444602d9..d85178507d 100644
--- a/documentation/components/components-treegrid.asciidoc
+++ b/documentation/components/components-treegrid.asciidoc
@@ -37,20 +37,11 @@ Populating a [classname]#TreeGrid# with in-memory data can be done as follows
 
 [source, java]
 ----
-Project rootProject = getRootRroject();
-
-TreeData<Project> data = new TreeData<>();
-// add a root level item with null parent
-data.addItem(null, rootProject);
-
-// Add all children for root item
-rootProject.flattened().forEach(
-       project -> data.addItems(project, project.getSubProjects()));
-
+// Initialize a TreeGrid and set in-memory data
 TreeGrid<Project> treeGrid = new TreeGrid<>();
-treeGrid.setDataProvider(new TreeDataProvider<>(data));
+treeGrid.setItems(getRootProjects(), Project::getSubProjects);
 
-// the first column gets the hierarchy indicator by default
+// The first column gets the hierarchy indicator by default
 treeGrid.addColumn(Project::getName).setCaption("Project Name");
 treeGrid.addColumn(Project::getHoursDone).setCaption("Hours Done");
 treeGrid.addColumn(Project::getLastModified).setCaption("Last Modified");
diff --git a/documentation/datamodel/datamodel-hierarchical.asciidoc b/documentation/datamodel/datamodel-hierarchical.asciidoc
index f405bc775f..24605adc53 100644
--- a/documentation/datamodel/datamodel-hierarchical.asciidoc
+++ b/documentation/datamodel/datamodel-hierarchical.asciidoc
@@ -27,7 +27,7 @@ Collection<Project> projects = service.getProjects();
 
 TreeData<Project> data = new TreeData<>();
 // add root level items
-data.addItems(null, projects);
+data.addItems(null, Project::getSubProjects);
 
 // add children for the root level items
 projects.forEach(project -> data.addItems(project, project.getChildren()));
@@ -42,7 +42,7 @@ When adding or removing items from the [classname]#TreeData#, you need to always
 
 [source, java]
 ----
-TreeData<Project> data = dataProvider.getData();
+TreeData<Project> data = dataProvider.getTreeData();
 data.addItem(null, newProject);
 data.addItems(newProject, newProject.getChildren());
 
@@ -93,8 +93,9 @@ The following code snippet shows a simple example on how to building a lazy hier
 
 [source, java]
 ----
-class FileSystemDataProvider
-      extends AbstractHierarchicalDataProvider<File, FilenameFilter> {
+class FileSystemDataProvider extends
+      AbstractBackEndHierarchicalDataProvider<File, FilenameFilter> {
+
   private final File root;
 
   public FileSystemDataProvider(File root) {
@@ -108,7 +109,7 @@ class FileSystemDataProvider
   }
 
   @Override
-  public Stream<File> fetchChildren(
+  public Stream<File> fetchChildrenFromBackEnd(
       HierarchicalQuery<File, FilenameFilter> query) {
     final File parent = query.getParentOptional().orElse(root);
     return query.getFilter()
@@ -121,11 +122,6 @@ class FileSystemDataProvider
   public boolean hasChildren(File item) {
     return item.list() != null && item.list().length > 0;
   }
-
-  @Override
-  public boolean isInMemory() {
-    return false;
-  }
 }
 ----