Merge branch '4182' into 'master'

Improve update performance of DynamicTreeTableViewer

See merge request !164

org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/.ratings

@@ -3,10 +3,10 @@ DynamicListContentProvider.java 817cba44f246a361207a88ef9a4e1869215803f7 GREEN
 DynamicStreamContentProvider.java f46e91400609cba54793dd240be0fe2aa0d5cced GREEN
 DynamicTextFieldTreeTableCell.java de24117e6f785b328f1ff62383626a0b4b54e8ff GREEN
 DynamicTreeContentProviderBase.java 91896b1fb5104d126544c44c1ff8c30f2a13a8d6 GREEN
-DynamicTreeItem.java 7486071d20e896d6ca9a9101bf105caccf3656d0 GREEN
+DynamicTreeItem.java 7e81ea98038b5eca90df583e0268d4e8f37aaf25 GREEN
 DynamicTreeItemBase.java d883066ecc181120302ca32f328538de7a45b093 GREEN
 DynamicTreeTableUIProviderBase.java d150a4c379cc41aab2a44a5f1643f4956332c8e3 GREEN
-DynamicTreeTableViewer.java cb289413d15159abbcccfea87d731738905b4b28 GREEN
+DynamicTreeTableViewer.java 62712ba0f72b57c55256648204566ac2448b8d56 GREEN
 DynamicTreeUIProviderBase.java 82d3c051213f0147f4c67ad247a08696cee73110 GREEN
 DynamicTreeViewer.java 545f1ca10b7b3cad171b294a4b447875da45c9ed GREEN
 DynamicTreeViewerBase.java a2013538b62d86f6a09efdf2cd78babac2072484 GREEN

org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/DynamicTreeItem.java

@@ -15,8 +15,10 @@
  *******************************************************************************/
 package org.fortiss.tooling.common.ui.javafx.control.treetableview;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.List;
 
 import javafx.scene.control.TreeItem;
 
@@ -37,24 +39,59 @@ public class DynamicTreeItem<T> extends DynamicTreeItemBase<T> {
 	/** {@inheritDoc} */
 	@Override
 	public void update() {
-		// remember expanded state of children
-		HashMap<T, TreeItem<T>> expanded = new HashMap<>();
-		for(TreeItem<T> c : getChildren()) {
-			if(c.isExpanded()) {
-				expanded.put(c.getValue(), c);
+
+		// This method is written so that in the common cases of deleting a child, inserting a child
+		// and swapping two children, it only updates the affected children. Especially in these
+		// common cases, this is much faster than clearing and re-populating the list of children.
+		List<TreeItem<T>> children = getChildren();
+
+		HashMap<T, Boolean> expanded = new HashMap<>();
+		for(TreeItem<T> child : children) {
+			expanded.put(child.getValue(), child.isExpanded());
+		}
+
+		Collection<? extends T> updatedContent =
+				contentProvider.getFilteredSortedChildren(getValue());
+
+		// List of values that are new since the last update
+		List<T> newlyAddedValues = new ArrayList<>(updatedContent);
+		for(TreeItem<T> child : children) {
+			newlyAddedValues.remove(child.getValue());
+		}
+
+		// Remove:
+		children.removeIf(ti -> !updatedContent.contains(ti.getValue()));
+
+		// Insert and Update:
+		// In the common cases where only new values have been inserted or values have been
+		// permuted, this will insert/modify only the affected values. This is faster than deleting
+		// all children and adding them from scratch.
+		int i = 0;
+		for(T updatedValue : updatedContent) {
+			DynamicTreeItem<T> child = null;
+			if(i < children.size()) {
+				if(updatedValue.equals(children.get(i).getValue())) {
+					// Child at position i already has the right value
+					child = (DynamicTreeItem<T>)children.get(i);
+				} else {
+					// There is a child at position i, but its value is incorrect
+					child = new DynamicTreeItem<T>(updatedValue, contentProvider);
+					child.setExpanded(expanded.getOrDefault(updatedValue, false));
+
+					if(newlyAddedValues.contains(updatedValue)) {
+						children.add(i, child);
+					} else {
+						children.set(i, child);
 					}
 				}
-		// get list of children and create tree items
-		getChildren().clear();
-		for(T element : contentProvider.getFilteredSortedChildren(getValue())) {
-			DynamicTreeItem<T> dti;
-			if(expanded.containsKey(element)) {
-				dti = (DynamicTreeItem<T>)expanded.get(element);
 			} else {
-				dti = new DynamicTreeItem<T>(element, contentProvider);
+				// There is no child at position i
+				child = new DynamicTreeItem<T>(updatedValue, contentProvider);
+				child.setExpanded(expanded.getOrDefault(updatedValue, false));
+				children.add(child);
 			}
-			getChildren().add(dti);
-			dti.update();
+			child.update();
+			i++;
 		}
 	}
 

org.fortiss.tooling.common.ui/src/org/fortiss/tooling/common/ui/javafx/control/treetableview/DynamicTreeTableViewer.java

@@ -16,15 +16,18 @@
 package org.fortiss.tooling.common.ui.javafx.control.treetableview;
 
 import static java.lang.Integer.MAX_VALUE;
+import static java.util.stream.Collectors.toList;
 import static javafx.scene.control.cell.CheckBoxTreeTableCell.forTreeTableColumn;
 
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
 
 import javafx.beans.property.SimpleObjectProperty;
+import javafx.collections.ObservableList;
 import javafx.scene.control.Label;
 import javafx.scene.control.SelectionMode;
 import javafx.scene.control.TreeItem;
@@ -139,11 +142,33 @@ public final class DynamicTreeTableViewer<T> extends DynamicTreeViewerBase<T> {
 	/** Updates the viewer content. */
 	public void update() {
 		// wild cast works: see constructor
-		IDynamicItem rootItem = (IDynamicItem)view.getRoot();
+		DynamicTreeItemBase<T> rootItem = (DynamicTreeItemBase<T>)view.getRoot();
+
+		List<T> selectedValues = getSelectedValues();
+		view.getSelectionModel().clearSelection();
 		rootItem.update();
+		selectValues(rootItem, selectedValues);
 		view.refresh();
 	}
 
+	/** Returns a list of all selected values */
+	private List<T> getSelectedValues() {
+		ObservableList<TreeItem<T>> selectedItems = view.getSelectionModel().getSelectedItems();
+		return selectedItems.stream().map(c -> c.getValue()).collect(toList());
+	}
+
+	/** Selects the given values in item's subtree */
+	private void selectValues(TreeItem<T> item, List<T> values) {
+		if(values.contains(item.getValue())) {
+			view.getSelectionModel().select(item);
+		}
+		if(item.isExpanded()) {
+			for(TreeItem<T> child : item.getChildren()) {
+				selectValues(child, values);
+			}
+		}
+	}
+
 	/** Expands items up to the given level. */
 	private void expandItem(TreeItem<T> parentItem, int revealLevel) {
 		if(revealLevel <= 0) {