Problem with PDE development

Question

In the basic project from the PDF workbench there is something like this:
      * the command has been executed, so extract extract the needed information
      * from the application context.
     public Object execute(ExecutionEvent event) throws ExecutionException {
          IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWindowChecked(event);
          MessageDialog.openInformation(window.getShell(),"Test", "Hello, Eclipse world");Now the call:
window.getShell()
gives this error:
"The method getShell() from the type IWorkbenchWindow refers to the missing type Shell"
Any ideas on what is wrong?
IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWind

Answer 1

These are the imports:
import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.ui.IWorkbenchWindow;
import org.eclipse.ui.handlers.HandlerUtil;
import org.eclipse.jface.dialogs.MessageDialog;
and this are the dependencies:
     <dependency>
          <groupId>swt</groupId>
          <artifactId>jface</artifactId>
          <version>3.0m8</version>
     </dependency>
     <dependency>
          <groupId>org.eclipse.core</groupId>
          <artifactId>commands</artifactId>
          <version>3.3.0-I20070605-0010</version>
     </dependency>          
     <dependency>
     <groupId>org.eclipse.ui</groupId>
     <artifactId>workbench</artifactId>
     <version>3.3.0-I20070608-1100</version>
     </dependency>     
They relate directly to the imports as I see them. But I don't get any errors unless I use the
          IWorkbenchWindow window = HandlerUtil.getActiveWorkbenchWindowChecked(event);
          window.getShell();
But maybe its not a good idea to move PDE to maven.