/*******************************************************************************
 * Copyright (c) 2000, 2016 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.snippets;

/*
 * Virtual Tree example snippet: create a tree with 10,000 items (lazy)
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 *
 * @since 3.0
 */
import org.eclipse.swt.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class Snippet144Tree {

static final int COUNT = 100_000;

public static void main(String[] args) {
	Display display = new Display ();
	final Shell shell = new Shell (display);
	shell.setLayout (new RowLayout (SWT.VERTICAL));
	final Tree tree = new Tree (shell, SWT.VIRTUAL | SWT.BORDER);
	TreeItem[] top = { null };
	tree.addListener (SWT.SetData, event -> {
		TreeItem item = (TreeItem) event.item;
		if (item.getParentItem() == null) {
			top[0] = item;
			item.setText("top");
		} else {
			int index = top[0].indexOf (item);
			item.setText ("Item " + index);
		}
		System.out.println (item.getText ());
	});
	tree.setLayoutData (new RowData (200, 200));
	Button button = new Button (shell, SWT.PUSH);
	button.setText ("&Add Items");
	final Label label = new Label(shell, SWT.NONE);
	button.addListener (SWT.Selection, event -> {
		long t1 = System.currentTimeMillis ();
		top[0].setItemCount (COUNT);
		top[0].setExpanded(true);
		long t2 = System.currentTimeMillis ();
		label.setText ("Items: " + COUNT + ", Time: " + (t2 - t1) + " (ms)");
		shell.layout ();
	});
	tree.setItemCount (1);
	shell.pack ();
	shell.open ();
	while (!shell.isDisposed ()) {
		if (!display.readAndDispatch ()) display.sleep ();
	}
	display.dispose ();
}
}