RCP: How to sync state of MMenuItem and MToolItem

Question

I have a handler which is linked to both a menu item and a toolbar icon. If the menu item is selected, a checkmark will appear to the left of the menu item. If the toolbar button is pressed in the icon changes to a 'sunken' to look like it's pushed in.

If the menu item is checkmarked I would like to 'auto-push' the toolbar button in (without firing another toolbar button-pressed event).

If the button is pressed in I would like the menu item to 'auto-checkmark'

Is there a way to do this? I assume it would start here..;

@Execute
public void execute(
    @Named(IServiceConstants.ACTIVE_SHELL) Shell shell, 
    @Optional MToolItem toolItem, 
    @Optional MMenuItem menuItem) {

  // Menu triggered coming into this method
  if (menuItem != null ) { 
    if(menuItem.isSelected()){
    ...
    }
  }

  // Button triggered coming into this method
  if (toolItem != null ) { 
    if(toolItem.isSelected()){
    ...
    }
  }

}

Answer 1

You need both MToolItem and MMenuItem before the first execution. You can find MToolItem via EModelService in a @PostConstruct method.

private MMenuItem menuItem;
private MToolItem toolItem;

@PostConstruct
protected void initControls(MApplication app) {
    setToolItem((MToolItem) modelService.find("tool.item.id", app));
}

As for menu item, it cannot be found in such a way via EModelService (in Eclipse 4.3 Kepler, not sure for Luna). That is how we do that in the same @PostConstruct method:

...
MUIElement window = modelService.find("main.window.id", app);
setMenuItem((MHandledMenuItem) findMenuElement("menu.item.id", window));
...

public static MMenuElement findMenuElement(String id, MUIElement searchRoot)
{
    if (id == null) {
        throw new IllegalArgumentException("id is null!");
    }

    if (id.length() == 0) {
        throw new IllegalArgumentException("Empty string is not allowed in id.");
    }

    if (searchRoot instanceof MMenuElement && id.equals(searchRoot.getElementId()))
    {
        return (MMenuElement) searchRoot;
    }

    if (searchRoot instanceof MTrimmedWindow)
    {
        MMenuElement findMenu = findMenuElement(id, ((MTrimmedWindow) searchRoot).getMainMenu());
        if (findMenu != null)
        {
            return findMenu;
        }
    }
    else if (searchRoot instanceof MPart)
    {
        List<MMenu> menus = ((MPart) searchRoot).getMenus();
        for (MMenu mm : menus)
        {
            MMenuElement findMenu = findMenuElement(id, mm);
            if (findMenu != null)
            {
                return findMenu;
            }
        }
    }
    else if (searchRoot instanceof MMenu)
    {
        List<MMenuElement> children = ((MMenu) searchRoot).getChildren();
        for (MMenuElement me : children)
        {
            MMenuElement findMenu = findMenuElement(id, me);
            if (findMenu != null)
            {
                return findMenu;
            }
        }
    }
    return null;
}