/*******************************************************************************
 * Copyright (c) 2007 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.SWTObservables;
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(SWTObservables.getRealm(display), new Runnable() {
			public void run() {
				Shell shell = new Shell(display);

				final WritableList list = new WritableList();

				Button button = new Button(shell, SWT.PUSH);
				button.setText("add");
				button.addSelectionListener(new SelectionAdapter() {
					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) {
					protected Widget createWidget(int index) {
						Label label = new Label(composite, SWT.BORDER);
						//requestLayout(label);
						return label;
					}

					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(new Integer(0), Integer.class);
			scheduleIncrementTask();
		}

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