examples/org.eclipse.jface.examples.databinding/src/org/eclipse/jface/examples/databinding/snippets/Snippet012CompositeUpdater.java

/*******************************************************************************
 * Copyright (c) 2007, 2018 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.jface.examples.databinding.snippets;

import java.util.Timer;
import java.util.TimerTask;

import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.core.databinding.observable.list.WritableList;
import org.eclipse.core.databinding.observable.value.WritableValue;
import org.eclipse.jface.databinding.swt.DisplayRealm;
import org.eclipse.jface.internal.databinding.provisional.swt.CompositeUpdater;
import org.eclipse.jface.layout.GridDataFactory;
import org.eclipse.jface.layout.GridLayoutFactory;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Widget;

/**
 * @since 3.2
 *
 */
public class Snippet012CompositeUpdater {

	public static void main(String[] args) {
		final Display display = new Display();
		Realm.runWithDefault(DisplayRealm.getRealm(display), () -> {
			Shell shell = new Shell(display);

			final WritableList list = new WritableList();

			Button button = new Button(shell, SWT.PUSH);
			button.setText("add");
			button.addSelectionListener(new SelectionAdapter() {
				@Override
				public void widgetSelected(org.eclipse.swt.events.SelectionEvent e) {
					list.add(0, new Counter());
				}
			});

			final Composite composite = new Composite(shell, SWT.None);

			new CompositeUpdater(composite, list) {
				@Override
				protected Widget createWidget(int index) {
					Label label = new Label(composite, SWT.BORDER);
					// requestLayout(label);
					return label;
				}

				@Override
				protected void updateWidget(Widget widget, Object element) {
					((Label) widget).setText(((Counter) element).getValue() + "");
					requestLayout((Label) widget);
				}
			};
			GridLayoutFactory.fillDefaults().numColumns(10).generateLayout(composite);

			GridDataFactory.fillDefaults().grab(true, true).applyTo(composite);

			GridLayoutFactory.fillDefaults().generateLayout(shell);
			shell.pack();
			shell.open();
			while (!shell.isDisposed()) {
				if (!display.readAndDispatch())
					display.sleep();
			}
		});
		display.dispose();
	}

	static Timer timer = new Timer(true);

	static class Counter extends WritableValue {
		Counter() {
			super(Integer.valueOf(0), Integer.class);
			scheduleIncrementTask();
		}

		private void scheduleIncrementTask() {
			timer.schedule(new TimerTask() {
				@Override
				public void run() {
					// we have to get onto the realm (UI thread) to perform the
					// increment
					getRealm().asyncExec(() -> {
						Integer currentVal = (Integer) getValue();
						setValue(Integer.valueOf(currentVal.intValue() + 1));
					});
					scheduleIncrementTask();
				}
			}, 1000);
		}
	}
}