Eclipse RCP: September 2007

Thursday, September 20, 2007

IBM Lotus Expeditor and Symphony

Dreams of IBM Lotus Symphony components appearing inside our Eclipse RCP application have quickly faded when reality tapped me on the side of the head with a large SOA middleware wiffle bat.

IBM Lotus Symphony is built on top of Eclipse RCP and IBM Lotus Expeditor. That is a key point. Your existing Eclipse RCP applications need to be ported to the IBM Lotus Expeditor environment. For example, the three IBM Lotus Symphony applications run inside the Expeditor.

For those who are interested, start with the following articles. I'm assuming you are comfortable developing Eclipse RCP applications. In fact, only Eclipse 3.2 RCP applications. If you have made the jump to Eclipse 3.3 you will have to wait. Also, you don't need to download IBM Lotus Symphony.

The last article shows how to port our favorite Eclipse RCP Mail Application into the IBM Lotus Expeditor SOA Middleware universe.

Wednesday, September 12, 2007

Sigue Sigue SIGTERM

Our IT group wondered if our Eclipse RCP based application could handle a linux system shutdown. They kept catching hell for rebooting computers at night to keep the batch processing system running. Our users would lose unsaved work and get grumpy. Grumpy seismic processors are not a pretty sight.

The trick is to teach the Eclipse RCP application to listen for a SIGTERM by adding a shutdown hook.

Please note that this does not work on Windows. More about this in a future blog.

public class IPEApplication implements IApplication {
  public Object start(IApplicationContext context) throws Exception {
    final Display display = PlatformUI.createDisplay();
    Runtime.getRuntime().addShutdownHook(new ShutdownHook());  }
    // start workbench...
  }
}

The shutdown code must be run in the UI thread and should not be run if the workbench is being closed by other means. All dirty editors are automatically saved. This avoids prompting the user who is probably at home sleeping when their computer is shutdown. Finally the workbench is closed.

private class ShutdownHook extends Thread {
  @Override
  public void run() {
    try {
      final IWorkbench workbench = PlatformUI.getWorkbench();
      final Display display = PlatformUI.getWorkbench()
                                        .getDisplay();
      if (workbench != null && !workbench.isClosing()) {
        display.syncExec(new Runnable() {
          public void run() {
            IWorkbenchWindow [] workbenchWindows = 
                            workbench.getWorkbenchWindows();
            for(int i = 0;i < workbenchWindows.length;i++) {
              IWorkbenchWindow workbenchWindow =
                                        workbenchWindows[i];
              if (workbenchWindow == null) {
                // SIGTERM shutdown code must access
                // workbench using UI thread!!
              } else {
                IWorkbenchPage[] pages = workbenchWindow
                                           .getPages();
                for (int j = 0; j < pages.length; j++) {
                  IEditorPart[] dirtyEditors = pages[j]
                                           .getDirtyEditors();
                  for (int k = 0; k < dirtyEditors.length; k++) {
                    dirtyEditors[k]
                             .doSave(new NullProgressMonitor());
                  }
                }
              }
            }
          }
        });
        display.syncExec(new Runnable() {
          public void run() {
            workbench.close();
          }
        });
      }
    } catch (IllegalStateException e) {
      // ignore
    }
  }
}

Monday, September 3, 2007

Cheat Sheet Editor

Eclipse Europa (3.3) has a new Cheat Sheet Editor which is a vast improvement over the XML editor used in the Calipso (3.2) release.

Create a cheat sheet, File->New->Other...->User Assistance->Cheat Sheets.
Enter a filename and click Finish.

The new Cheat Sheet Editor will appear. Select the Item and you will see the definition and command sections appear to the right. Click the Browse... button to see the new Command Composer.

The Command Composer shows a list of available commands and their parameters. Gone are the days of hunting through eclipse plugin.xml files looking for command ids.

In the Command Composer, select Window->Preferences.
Use the Preference Page combo box to select General->Editors->File Associations.
Click OK.

You now have a cheat sheet item which will display the File Association preference page.

If you want to see what happens inside Eclipse, display the ParameterizedCommand class and set a break point at executeWithChecks(Object, Object). Now run your application in debug mode, display your cheat sheet and press "Click to perform".

The command org.eclipse.ui.window.preferences is defined in org.eclipse.ui/plugin.xml. Its default handler is ShowPreferencePageHandler which is found in the org.eclipse.ui.workbench plugin.

Read up on the following extension points and use the ShowPreferencePageHandler as an template to build your own commands that can be accessed from a cheat sheet. See New menu contribution extension for readings on how to use a command in a menu, toolbar, or popup menu.

org.eclipse.ui.commands: A logical representation of a task. A handler does the work. See wiki and help guide.
org.eclipse.ui.handlers: A handler does what the command represents. See wiki and help guide.

Eclipse RCP