Eclipse RCP: Can I remove Orphaned Perspectives from the Perspective Bar? - eclipse-rcp

Question

I'm developing an RCP that has two product versions, a core app and one with some extensions. If a user opens the core app after having opened the extended app in the same workspace, eclipse detects a perspective used only in the extended app and makes a local copy of it, so it shows up in the perspective toolbar as an orphaned extension.
I created an activity to hide the extended app perspective when running the core app. That hides it from the perspective menu and the perspective shortcut menu, but it doesn't remove it from the perspective toolbar.I also tried detecting orphaned perspectives from the active page of the active workbench window (by looking for angle brackets in the label) and removing them with PlatformUI.getWorkbench().getPerspectiveRegistry().deletePerspective(perspective), but this doesn't affect the perspective toolbar either. The perspective I'm removing is not present in the core app.
Is there a way I can access the perspective toolbar programmatically so I can remove any orphaned perspectives? Or any other approach tha would work?

Answer 1

I thought a good solution would be creating a custom perspective switcher, but that path was blocked by an eclipse bug. There is a suggested workaround, but it did not work for me. I created a custom perspective switcher toolbar, but I could find no way to make it update when perspectives are opened or activated. My attempts are documented here.
I removed the orphan perspectives in a workspace shutdown hook, but for some reason an NPE is thrown by the E4 workbench (LazyStackRenderer line 238) when I select a perspective in the switcher that was opened but not selected when I launched the app.
I got it to work as desired by closing all open perspectives on shutdown, after storing their IDs in a preference value, and then opening them again when the app is launched in the WorkbenchWindowAdvisor. It's a bit of a hack, but it's the only way I could find to avoid the E4 workbench NPE, which also prevents setting the perspective from the toolbar until it's closed and re-opened from the Window menu.
Here's my code.
...
IWorkbench workbench = ...
static final String PERPSECTIVE_ID_1 = ...
static fnal String PERSPECTIVE_ID_2 = ...
static final String PREFERENCE_KEY = ...
workbench.addWorkbenchListener( new IWorkbenchListener() {
public boolean preShutdown( IWorkbench workbench, boolean forced ) {
IPerspectiveDescriptor[] openPerspectives = page.getOpenPerspectives();
page.closeAllPerspectives(false, false);
StringBuilder sb = new StringBuilder();
String delim = "";
for (IPerspectiveDescriptor persp : openPerspectives) {
if (!persp.getId().equals(PERSPECTIVE_ID_1) && !persp.getId().equals(PERSPECTIVE_ID_2) {
sb.append(delim + persp.getId());
delim = ";";
}
}
getPreferenceStore().setValue(PREF_KEY, sb.toString());
return true;
}
public void postShutdown( IWorkbench workbench ) {
}
});
class MyWorkbenchWindowAdvisor extends WorkbenchWindowAdvisor {
static final String PRODUCT_ID_1 = ...
static final String PRODUCT_ID_2 = ...
static final String PREFERENCE_KEY = ...
...
#Override
public void postWindowOpen() {
IWorkbenchPage page = getWindowConfigurer().getWindow().getActivePage();
String savedOpenPerspectiveStr = getPreferenceStore().getString(PREFERENCE_KEY);
if (!"".equals(savedOpenPerspectiveStr)) {
List<IPerspectiveDescriptor> openPerspectives = new ArrayList<IPerspectiveDescriptor>();
String[] perspectiveIds = savedOpenPerspectiveStr.split(";");
if (perspectiveIds.length == 0) {
openPerspectives.add(PlatformUI.getWorkbench().getPerspectiveRegistry().findPerspectiveWithId(savedOpenPerspectiveStr));
} else {
for (String id : perspectiveIds) {
openPerspectives.add(PlatformUI.getWorkbench().getPerspectiveRegistry().findPerspectiveWithId(id));
}
}
//successively setting perspectives causes them to appear in the perspective switcher toolbar
for (IPerspectiveDescriptor persp : openPerspectives) {
page.setPerspective(persp);
}
}
//now we set the appropriate perspective
if (Platform.getProduct().getId().equals(PRODUCT_ID_1)) {
page.setPerspective(PlatformUI.getWorkbench().getPerspectiveRegistry().findPerspectiveWithId(PERSPECTIVE_ID_1));
} else if (Platform.getProduct().getId().equals(PRODUCT_ID_2)) {
page.setPerspective(PlatformUI.getWorkbench().getPerspectiveRegistry().findPerspectiveWithId(PERSPECTIVE_ID_2));
}
}
...
}