org.eclipse.ui.internal.browser.OpenBrowserHandler.execute(ExecutionEvent)

Hi,

I have a Handled Toolitem toolbar contribution. Previously, this toolitem was handled by org.eclipse.ui.browser.openBrowser, but now I need to not only open a browser, but also perform some other bookkeeping action. To avoid code duplication, I decided to implement my own command such that it executes org.eclipse.ui.browser.openBrowser:

@Execute
public void execute(ECommandService commandService, EHandlerService handlerService) {
  // do bookkeeping
  Map parameters = new HashMap();
  parameters.put("url", "http://www.example.org/");
  Command command = commandService.createCommand("org.eclipse.ui.browser.openBrowser", parameters);
  handlerService.executeHandler(command);
}

Unfortunately, executing the command like this changes behavior: Where before the browser was opened in an editor, now it opens a new window (of Firefox, in my case).

I suspect this is because the IEclipseContext, in which the org.eclipse.ui.browser.openBrowser command handler is looked up changes. But injecting the IEclipseContext into my custom command and then using

handlerService.executeHandler(command, eclipseContext);

doesn't do the trick either.

So, how do I execute a command from within another command in the same context (or at least in a context so similar that the behavior of openBrowser doesn't change)?

Thanks for the pointer.

I know about OpenBrowserHandler and the General > Web Browser preference page, but reviewing that I noticed something odd: as soon as my command executes (and opens an external browser), the Use internal web browser radio button is disabled. Apparently, my command breaks something.

Digging a bit further I found this message on the console:

!ENTRY org.eclipse.ui.browser 2 0 2016-03-07 18:31:38.853
!MESSAGE Internal browser is not available: Invalid thread access

It looks like that a command executed from within another command does not run on the UI thread. The "outer" command runs on the main thread, the "inner" on (in my case) "Worker-9".

Is this to be expected? And is there any way to avoid this?

Are you sure the trigger of your outer handler is called within the UI thread? Does not look like.

1. Do I have to ensure that EHandlerService.executeHandler is executed on the UI thread myself?
   
2. What assumptions can an @Execute method make about the thread it's running on? In particular, shouldn't OpenBrowserHandler be able to execute on arbitrary threads?
   

Coming to this late. The handler service does not shunt requests onto the UI thread. Although most commands are related to UI features, the command/handler framework can be used for headless or background purposes.

Your @Execute shouldn't make any assumptions of threadedness.

High quality patches are always welcome

Hi,

I have a Handled Toolitem toolbar contribution. Previously, this toolitem was handled by org.eclipse.ui.browser.openBrowser, but now I need to not only open a browser, but also perform some other action. To avoid code duplication, I decided to implement my own command such that it executes org.eclipse.ui.browser.openBrowser:

@Execute
public void execute(ECommandService commandService, EHandlerService handlerService) {
  // do bookkeeping
  Map parameters = new HashMap();
  parameters.put("url",  
  Command command = commandService.createCommand("org.eclipse.ui.browser.openBrowser", parameters);
  handlerService.executeHandler(command);
}

Unfortunately, executing the command like this changes behavior: Where before the browser was opened in an editor, now it opens a new window (of Firefox, in my case).

I suspect this is because the IEclipseContext, in which the org.eclipse.ui.browser.openBrowser command handler is looked up changes. But injecting the IEclipseContext into my custom command and then using

handlerService.executeHandler(command, eclipseContext);

doesn't do the trick either.

So, how do I execute a command from within another command in the same context (or at least in a context so similar that the behavior of openBrowser doesn't change)?