7091: JOverflow Instance View table should be sortable by clicking he…

…aders

Reviewed-by: hirt

application/org.openjdk.jmc.joverflow.ui/src/main/java/org/openjdk/jmc/joverflow/ui/viewers/JavaThingTreeViewer.java

@@ -1,6 +1,6 @@
 /*
- * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2019, Red Hat Inc. All rights reserved.
+ * Copyright (c) 2018, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2021, Red Hat Inc. All rights reserved.
  *
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -42,9 +42,12 @@
 import org.eclipse.jface.viewers.ITreeContentProvider;
 import org.eclipse.jface.viewers.TreeViewer;
 import org.eclipse.jface.viewers.TreeViewerColumn;
+import org.eclipse.jface.viewers.Viewer;
+import org.eclipse.jface.viewers.ViewerComparator;
 import org.eclipse.swt.SWT;
+import org.eclipse.swt.events.SelectionEvent;
+import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.widgets.Composite;
-
 import org.openjdk.jmc.joverflow.heap.model.JavaField;
 import org.openjdk.jmc.joverflow.heap.model.JavaObject;
 import org.openjdk.jmc.joverflow.heap.model.JavaObjectArray;
@@ -53,17 +56,49 @@
 import org.openjdk.jmc.joverflow.ui.model.JavaThingItem;
 
 public class JavaThingTreeViewer<T extends JavaThingItem> extends TreeViewer {
+	private static final String ELLIPSIS = "..."; //$NON-NLS-1$
+	private static final String NAME_COLUMN = "Name"; //$NON-NLS-1$
+	private static final String SIZE_COLUMN = "Size"; //$NON-NLS-1$
+	private static final String VALUE_COLUMN = "Value"; //$NON-NLS-1$
+
 	public JavaThingTreeViewer(Composite parent, int style) {
 		super(parent, style);
 
 		setContentProvider(new JavaThingItemContentProvider());
 
-		createTreeViewerColumn("Name", T::getName);
-		createTreeViewerColumn("Value", T::getValue);
-		createTreeViewerColumn("Size", T::getSize);
+		createTreeViewerColumn(NAME_COLUMN, T::getName);
+		createTreeViewerColumn(VALUE_COLUMN, T::getValue);
+		createTreeViewerColumn(SIZE_COLUMN, T::getSize);
 
 		getTree().setLinesVisible(true);
 		getTree().setHeaderVisible(true);
+
+		setComparator(new ViewerComparator() {
+			@Override
+			public int compare(Viewer viewer, Object e1, Object e2) {
+				JavaThingItem item1 = (JavaThingItem) e1;
+				JavaThingItem item2 = (JavaThingItem) e2;
+				// keep the overflow ellipsis row at the bottom of the view
+				if (item1.getName().equals(ELLIPSIS)) {
+					return SWT.MAX;
+				} else if (item2.getName().equals(ELLIPSIS)) {
+					return -SWT.MAX;
+				}
+				int result = 0;
+				int sortDirection = getTree().getSortDirection() == SWT.UP ? 1
+						: getTree().getSortDirection() == SWT.DOWN ? -1 : SWT.NONE;
+				if (getTree().getSortColumn() != null) {
+					if (getTree().getSortColumn().getText().equals(NAME_COLUMN)) {
+						result = item1.getName().compareTo(item2.getName());
+					} else if (getTree().getSortColumn().getText().equals(VALUE_COLUMN)) {
+						result = item1.getValue().compareTo(item2.getValue());
+					} else if (getTree().getSortColumn().getText().equals(SIZE_COLUMN)) {
+						result = Integer.parseInt(item1.getSize()) - Integer.parseInt(item2.getSize());
+					}
+				}
+				return result * sortDirection;
+			}
+		});
 	}
 
 	private void createTreeViewerColumn(String label, Function<T, String> labelProvider) {
@@ -79,6 +114,24 @@ public String getText(Object element) {
 				return labelProvider.apply((T) element);
 			}
 		});
+
+		column.getColumn().addSelectionListener(new SelectionListener() {
+			@Override
+			public void widgetSelected(SelectionEvent e) {
+				int newSortDirection = SWT.DOWN;
+				if (getTree().getSortColumn() != null
+						&& getTree().getSortColumn().getText().equals(column.getColumn().getText())) {
+					newSortDirection = getTree().getSortDirection() == SWT.UP ? SWT.DOWN : SWT.UP;
+				}
+				getTree().setSortColumn(column.getColumn());
+				getTree().setSortDirection(newSortDirection);
+				refresh();
+			}
+
+			@Override
+			public void widgetDefaultSelected(SelectionEvent e) {
+			}
+		});
 	}
 
 	private class JavaThingItemContentProvider implements ITreeContentProvider {