vogella.de

The Eclipse Jobs API provides background capabilities to Eclipse with can also be used in Eclipse RCP.

The important parts of the Job API are:

Using the Jobs API in Eclipse RCP is the same as in Eclipse plug-in development therefore I just give a small example. Check the appendix for a general introduction to the Eclipse Jobs API.

The following assumes that you are familiar with Eclipse RCP development .

Create a new Eclipse RCP project "de.vogella.jobs.first" with the "Hello RCP" example. Create one command "de.vogella.jobs.first.runJob1" with the following default handler.

			
package de.vogella.jobs.first.handler;


import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.Status;
import org.eclipse.core.runtime.jobs.Job;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.ui.handlers.HandlerUtil;

public class RunJob1 extends AbstractHandler {

	@Override
	public Object execute(final ExecutionEvent event) throws ExecutionException {
		Job job = new Job("First Job"){
			@Override
			protected IStatus run(IProgressMonitor monitor) {
				
				for (int i=0; i<10; i++){
					try {
						Thread.sleep(100);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println("Doing something");
				}
				HandlerUtil.getActiveShell(event).getDisplay().getDefault().asyncExec(new Runnable() {
		               public void run() {
		            	   MessageDialog.openInformation(HandlerUtil.getActiveShell(event), "Info", "Info for you");
		               }
				});
				

				

				return Status.OK_STATUS;
			}
			
		}; 
		
		job.schedule();
		return null;
	}

}

		

Add the command to the menu.

Run your application to see the Job API in action.

If you perform long running operations you should provide the user some information about the long running job. A good way of doing this is to show a progress indicator or a progress dialog.

Create a new project "de.vogella.rcp.intro.progress" with "Hello RCP" as a template. Create the command "de.vogella.rcp.intro.progress.showDialog" with the default handler "de.vogella.rcp.intro.progress.handler.ShowDialog". Create the handler class.

			
package de.vogella.rcp.intro.progress.handler;

import java.lang.reflect.InvocationTargetException;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.jface.dialogs.ProgressMonitorDialog;
import org.eclipse.jface.operation.IRunnableWithProgress;
import org.eclipse.ui.handlers.HandlerUtil;

public class ShowDialog extends AbstractHandler {

	@Override
	public Object execute(ExecutionEvent event) throws ExecutionException {
		ProgressMonitorDialog dialog = new ProgressMonitorDialog(HandlerUtil
				.getActiveShell(event).getShell());
		try {
			dialog.run(true, true, new IRunnableWithProgress() {
				@Override
				public void run(IProgressMonitor monitor) {
					monitor
							.beginTask("Doing something timeconsuming here",
									100);
					for (int i = 0; i < 10; i++) {
						if (monitor.isCanceled())
							return;
						monitor.subTask("I'm doing something here " + i);
						sleep(1000);
						monitor.worked(i);
					}
					monitor.done();
				}
			});
		} catch (InvocationTargetException e) {
			e.printStackTrace();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}

		return null;
	}

	private void sleep(Integer waitTime) {
		try {
			Thread.sleep(waitTime);
		} catch (Throwable t) {
			System.out.println("Wait time interrupted");
		}
	}

}

		

Add this command to the menu.

Run the application. Your command should open a dialog which show the process.

Thank you for practicing with this tutorial.

Please note that I maintain this website in my private time. If you like the information I'm providing please help me by donating.

For questions and discussion around this article please use the www.vogella.de Google Group. Also if you note an error in this article please post the error and if possible the correction to the Group.

I believe the following is a very good guideline for asking questions in general and also for the Google group How To Ask Questions The Smart Way.