alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

What this is

This file is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Other links

The source code

/*******************************************************************************
 * Copyright (c) 2006 Tom Schindl 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:
 *     Tom Schindl - initial API and implementation
 *******************************************************************************/

package org.eclipse.jface.snippets.viewers;

import org.eclipse.jface.viewers.IStructuredContentProvider;
import org.eclipse.jface.viewers.ITableLabelProvider;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.jface.viewers.TableViewer;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.TableColumn;

/**
 * Example how to update a viewer from a long running task
 *
 * @author Tom Schindl <tom.schindl@bestsolution.at>
 *
 */
public class Snippet046UpdateViewerFromBackgroundThread {
	private static Image[] images;

	private class MyContentProvider implements IStructuredContentProvider {

		/* (non-Javadoc)
		 * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
		 */
		public Object[] getElements(Object inputElement) {
			return (MyModel[])inputElement;
		}

		/* (non-Javadoc)
		 * @see org.eclipse.jface.viewers.IContentProvider#dispose()
		 */
		public void dispose() {

		}

		/* (non-Javadoc)
		 * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
		 */
		public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {

		}

	}

	public class MyModel {
		public int counter;
		public boolean finished;

		public MyModel(int counter) {
			this.counter = counter;
		}

		public String toString() {
			return "Item " + this.counter;
		}
	}

	public class MyLabelProvider extends LabelProvider implements ITableLabelProvider {

		public Image getColumnImage(Object element, int columnIndex) {
			if( columnIndex == 0 ) {
				return images[((MyModel)element).finished?0:1];
			}

			return null;
		}

		public String getColumnText(Object element, int columnIndex) {
			return "Column " + columnIndex + " => " + element.toString();
		}

	}

	private static Image createImage(Display display, int red, int green, int blue) {
		Color color = new Color(display,red,green,blue);
		Image image = new Image(display,10,10);
		GC gc = new GC(image);
		gc.setBackground(color);
		gc.fillRectangle(0, 0, 10, 10);
		gc.dispose();

		return image;
	}

	public Snippet046UpdateViewerFromBackgroundThread(Shell shell) {
		final TableViewer v = new TableViewer(shell,SWT.BORDER|SWT.FULL_SELECTION);
		v.setLabelProvider(new MyLabelProvider());
		v.setContentProvider(new MyContentProvider());

		TableColumn column = new TableColumn(v.getTable(),SWT.NONE);
		column.setWidth(200);
		column.setText("Column 1");

		column = new TableColumn(v.getTable(),SWT.NONE);
		column.setWidth(200);
		column.setText("Column 2");

		final MyModel[] model = createModel();
		v.setInput(model);
		v.getTable().setLinesVisible(true);
		v.getTable().setHeaderVisible(true);

		Button b = new Button(shell,SWT.PUSH);
		b.setText("Start Long Task");
		b.addSelectionListener(new SelectionAdapter() {

			public void widgetSelected(SelectionEvent e) {
				final Thread t = new Thread() {

					public void run() {
						for( int i = 0; i < model.length; i++ ) {
							if( v.getTable().isDisposed()) {
								return;
							}
							final int j = i;
							v.getTable().getDisplay().asyncExec(new Runnable() {

								public void run() {
									model[j].finished = true;
									v.update(model[j], null);
								}

							});
							try {
								Thread.sleep(1000);
							} catch (InterruptedException e) {
								e.printStackTrace();
							}
						}
					}
				};
				t.start();
			}
		});
	}

	private MyModel[] createModel() {
		MyModel[] elements = new MyModel[10];

		for( int i = 0; i < 10; i++ ) {
			elements[i] = new MyModel(i);
		}

		return elements;
	}

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Display display = new Display ();

		images = new Image[2];
		images[0] = createImage(display,0,255,0);
		images[1] = createImage(display,255,0,0);

		Shell shell = new Shell(display);
		shell.setLayout(new FillLayout());
		new Snippet046UpdateViewerFromBackgroundThread(shell);
		shell.open ();

		while (!shell.isDisposed ()) {
			if (!display.readAndDispatch ()) display.sleep ();
		}

		for( int i = 0; i < images.length; i++ ) {
			images[i].dispose();
		}

		display.dispose ();

	}

}
... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.