when reset perspective is done on E4 error occurs - reset

Question

When reset Perspective code is done as in the given link https://www.eclipse.org/forums/index.php/m/1209165/srch=reset+perspective+in+e4#msg_1209165
and code called is
The code is as follows
public class ResetPerspective {
// private static final String MAIN_PERSPECTIVE_STACK_ID = "MainPerspectiveStack";
#Execute
public void execute(#Named(IServiceConstants.ACTIVE_SHELL) Shell shell,
EModelService modelService, MApplication app,
EPartService partService) {
MWindow window = (MWindow) modelService.find("Main", app); //main
final MPerspective perspective = modelService.getActivePerspective(window);
final MUIElement snippet = modelService.cloneSnippet(app,
perspective.getElementId(), window);
snippet.setToBeRendered(true);
if (snippet != null) {
MElementContainer<MUIElement> parent = perspective.getParent();
perspective.setToBeRendered(false);
List<MWindow> existingDetachedWindows = new ArrayList<MWindow>();
existingDetachedWindows.addAll(perspective.getWindows());
MPerspective dummyPerspective = (MPerspective) snippet;
while (dummyPerspective.getWindows().size() > 0) {
MWindow detachedWindow = dummyPerspective.getWindows()
.remove(0);
perspective.getWindows().add(detachedWindow);
}
parent.getChildren().remove(perspective);
parent.getChildren().add(snippet);
System.out.println(parent.getChildren().get(0).getElementId());
partService.switchPerspective((MPerspective) snippet);
}
}
}
and reset perspective is selected gives the following error
The error is as follows
!ENTRY org.eclipse.e4.ui.workbench 4 0 2014-06-10 11:28:54.063
!MESSAGE Internal Error
!STACK 0
org.eclipse.e4.core.di.InjectionException: java.lang.IllegalArgumentException:
at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:63)
at org.eclipse.e4.core.internal.di.InjectorImpl.invokeUsingClass(InjectorImpl.java:243)
at org.eclipse.e4.core.internal.di.InjectorImpl.invoke(InjectorImpl.java:224)
at org.eclipse.e4.core.contexts.ContextInjectionFactory.invoke(ContextInjectionFactory.java:132)
at org.eclipse.e4.core.commands.internal.HandlerServiceHandler.execute(HandlerServiceHandler.java:167)
at org.eclipse.core.commands.Command.executeWithChecks(Command.java:499)
at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:508)
at org.eclipse.e4.core.commands.internal.HandlerServiceImpl.executeHandler(HandlerServiceImpl.java:213)
at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.executeItem(HandledContributionItem.java:850)
at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.handleWidgetSelection(HandledContributionItem.java:743)
at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.access$7(HandledContributionItem.java:727)
at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem$4.handleEvent(HandledContributionItem.java:662)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1057)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4170)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3759)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1113)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:997)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:140)
at org.eclipse.e4.ui.internal.workbench.swt.E4Application.start(E4Application.java:162)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:354)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:181)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:636)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:591)
at org.eclipse.equinox.launcher.Main.run(Main.java:1450)
at org.eclipse.equinox.launcher.Main.main(Main.java:1426)
Caused by: java.lang.IllegalArgumentException:
at org.eclipse.core.runtime.Assert.isLegal(Assert.java:63)
at org.eclipse.core.runtime.Assert.isLegal(Assert.java:47)
at org.eclipse.e4.ui.internal.workbench.ModelServiceImpl.findElementsRecursive(ModelServiceImpl.java:286)
at org.eclipse.e4.ui.internal.workbench.ModelServiceImpl.findElements(ModelServiceImpl.java:371)
at org.eclipse.e4.ui.internal.workbench.ModelServiceImpl.getActivePerspective(ModelServiceImpl.java:1075)
at bomb.handlers.ResetPerspective.execute(ResetPerspective.java:44)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:56)
... 33 more

Answer 1

It looks like you do not have a window in your application model with the id "Main" so modelService.find("Main", app) is returning null. null is an illegal argument for modelService.getActivePerspective(window) so you get an error.
You must adapt this code you found to use the ids for your application. You must also follow the instructions for creating snippets for the perspectives.