Eclipse PluginDevelopment-Handlerclass不是由plugin.xml启动的

Question

Iam working at a project which shall open a View. It shall be opened by the contextmenu-entry. But it does not work. Everytime I open the contextmenu inside the new Eclipse Workspace, I get a Exception and it does not open the Handler someorg.handlers.ShowViewHandler

!MESSAGE Exception while dispatching event org.osgi.service.event.Event

I commented the plugin.xml with "what i expect it does"

Can anyone tell me what the problem is / why the handlerclass is not started?

<plugin>
     <extension point="org.eclipse.ui.commands">
      <command
            id="someorg.editor.ShowView"
            name="ShowView">
            <commandParameter
                  id="FeatureType"
                  name="feature type"
                  optional="false"
            />
      </command>
    </extension>

    <extension point="org.eclipse.ui.menus"><!--adds a contextmenu entry with the name "ShowtheView..."-->
        <menuContribution locationURI="popup:#TextEditorContext?after=group.find" > 
            <command
                 commandId="someorg.editor.ShowView"
                 label="ShowTheView...">
                <visibleWhen checkEnabled="false">
                    <reference definitionId="someorg.Editor.opened">
                    </reference>
                </visibleWhen>
                <parameter name="Type" value="ViewThis"/>
            </command>
        </menuContribution>
    </extension>

    <extension point="org.eclipse.ui.handlers"><!--opens the handlerclass "someorg.handlers.ShowViewHandler" where the View is computed.-->
        <handler
            class="someorg.handlers.ShowViewHandler"
            commandId="someorg.editor.ShowView">
            <activeWhen>
                <reference
                    definitionId="someorg.Editor.opened">
                </reference>
            </activeWhen>
        </handler>
    </extension>


    <!--some other (independent) declarations-->

Full Errorlog after opening context menu:

!ENTRY org.eclipse.equinox.event 4 0 2016-02-25 12:00:25.511
!MESSAGE Exception while dispatching event org.osgi.service.event.Event [topic=org/eclipse/e4/ui/model/ui/ElementContainer/children/ADD] {ChangedElement=org.eclipse.e4.ui.model.application.ui.menu.impl.PopupMenuImpl@cd19d0a (elementId: #TextEditorContext, tags: [menuContribution:popup, popup:#TextEditorContext, popup:someorg.EditorContext, popup:#AbstractTextEditorContext], contributorURI: null) (widget: Menu {&Undo Ctrl+Z, Re&vert File, &Save Ctrl+S, |, Quick Outline    Ctrl+O, Open Source File, Quick Outline Ctrl+O, Open Declaration    F3, Open Call Hierarchy Ctrl+Alt+H, Quick Hierarchy Ctrl+T, Open Type in Hierarchy  F4, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Open Call Hierarchy Ctrl+Alt+H, Quick Hierarchy Ctrl+T, Open Type in Hierarchy  F4, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Open with SceneBuilder, Open W&ith, Sho&w In    Alt+Shift+W, |, Cu&t    Ctrl+X, &Copy   Ctrl+C, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, &Paste    Ctrl+V, |, Rename Element   Alt+Shift+R, Validate, Validate, Validate, Extract Local Variable   Alt+Shift+L, Organize Imports   Ctrl+Shift+O, Rename Element    Alt+Shift+R, Validate, Rename Element   Alt+Shift+R, Validate, Extract Local Variable   Alt+Shift+L, Organize Imports   Ctrl+Shift+O, Rename Element    Alt+Shift+R, Validate, Validate, Rename Element Alt+Shift+R, Validate, Validate, Rename Element Alt+Shift+R, Validate, Validate, Rename Element Alt+Shift+R, Validate, Rename Element   Alt+Shift+R, Validate, Validate, Validate, Validate, Validate, Validate, Validate, Validate, Validate, &Quick Fix   Ctrl+1, |, ShowTheView, Find References Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, |, Wa&tch, Build & Export FX Application, Upgrade to EclipseLink Mapping File, Upgrade JPA Document Version, Synchronize Class List, Retrieve Context, Explore, I&mport from Repository..., Register As Service...    Ctrl+Shift+F10, |, Pre&ferences...}, renderer: null, toBeRendered: true, onTop: false, visible: true, containerData: null, accessibilityPhrase: null) (label: null, iconURI: null, tooltip: null, mnemonics: null) (enabled: true) (context: popup:#TextEditorContext, variables: null), Widget=Menu {&Undo Ctrl+Z, Re&vert File, &Save Ctrl+S, |, Quick Outline    Ctrl+O, Open Source File, Quick Outline Ctrl+O, Open Declaration    F3, Open Call Hierarchy Ctrl+Alt+H, Quick Hierarchy Ctrl+T, Open Type in Hierarchy  F4, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Open Call Hierarchy Ctrl+Alt+H, Quick Hierarchy Ctrl+T, Open Type in Hierarchy  F4, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Quick Outline   Ctrl+O, Open with SceneBuilder, Open W&ith, Sho&w In    Alt+Shift+W, |, Cu&t    Ctrl+X, &Copy   Ctrl+C, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, Copy Qualified Name, &Paste    Ctrl+V, |, Rename Element   Alt+Shift+R, Validate, Validate, Validate, Extract Local Variable   Alt+Shift+L, Organize Imports   Ctrl+Shift+O, Rename Element    Alt+Shift+R, Validate, Rename Element   Alt+Shift+R, Validate, Extract Local Variable   Alt+Shift+L, Organize Imports   Ctrl+Shift+O, Rename Element    Alt+Shift+R, Validate, Validate, Rename Element Alt+Shift+R, Validate, Validate, Rename Element Alt+Shift+R, Validate, Validate, Rename Element Alt+Shift+R, Validate, Rename Element   Alt+Shift+R, Validate, Validate, Validate, Validate, Validate, Validate, Validate, Validate, Validate, &Quick Fix   Ctrl+1, |, ShowTheView..., Find References  Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, Find References   Ctrl+Shift+G, |, Wa&tch, Build & Export FX Application, Upgrade to EclipseLink Mapping File, Upgrade JPA Document Version, Synchronize Class List, Retrieve Context, Explore, I&mport from Repository..., Register As Service...    Ctrl+Shift+F10, |, Pre&ferences...}, AttName=children, NewValue=org.eclipse.e4.ui.model.application.ui.menu.impl.HandledMenuItemImpl@6a2e7d2d (elementId: someorg.Editor.ShowView, tags: [], contributorURI: null) (widget: MenuItem {ShowTheView}, renderer: org.eclipse.e4.ui.workbench.renderers.swt.MenuManagerRenderer@40e420fe, toBeRendered: true, onTop: false, visible: true, containerData: null, accessibilityPhrase: null) (label: ShowTheView..., iconURI: null, tooltip: null, enabled: true, selected: false, type: Push) (mnemonics: null) (wbCommand: null), EventType=ADD, Position=92} to handler org.eclipse.e4.ui.internal.di.UIEventObjectSupplier$UIEventHandler@60cb098b
!STACK 0
org.eclipse.e4.core.di.InjectionException: java.lang.NullPointerException
    at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:68)
    at org.eclipse.e4.ui.internal.di.UIEventObjectSupplier$UIEventHandler$1.run(UIEventObjectSupplier.java:56)
    at org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:186)
    at org.eclipse.ui.internal.UISynchronizer.syncExec(UISynchronizer.java:145)
    at org.eclipse.swt.widgets.Display.syncExec(Display.java:4761)
    at org.eclipse.e4.ui.internal.workbench.swt.E4Application$1.syncExec(E4Application.java:211)
    at org.eclipse.e4.ui.internal.di.UIEventObjectSupplier$UIEventHandler.handleEvent(UIEventObjectSupplier.java:53)
    at org.eclipse.equinox.internal.event.EventHandlerWrapper.handleEvent(EventHandlerWrapper.java:197)
    at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:197)
    at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:1)
    at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
    at org.eclipse.osgi.framework.eventmgr.ListenerQueue.dispatchEventSynchronous(ListenerQueue.java:148)
    at org.eclipse.equinox.internal.event.EventAdminImpl.dispatchEvent(EventAdminImpl.java:135)
    at org.eclipse.equinox.internal.event.EventAdminImpl.sendEvent(EventAdminImpl.java:78)
    at org.eclipse.equinox.internal.event.EventComponent.sendEvent(EventComponent.java:39)
    at org.eclipse.e4.ui.services.internal.events.EventBroker.send(EventBroker.java:85)
    at org.eclipse.e4.ui.internal.workbench.UIEventPublisher.notifyChanged(UIEventPublisher.java:59)
    at org.eclipse.emf.common.notify.impl.BasicNotifierImpl.eNotify(BasicNotifierImpl.java:374)
    at org.eclipse.emf.ecore.util.EcoreEList.dispatchNotification(EcoreEList.java:249)
    at org.eclipse.emf.common.notify.impl.NotifyingListImpl.addUnique(NotifyingListImpl.java:356)
    at org.eclipse.emf.common.util.AbstractEList.add(AbstractEList.java:341)
    at org.eclipse.e4.ui.workbench.renderers.swt.ContributionRecord.mergeIntoModel(ContributionRecord.java:250)
    at org.eclipse.e4.ui.workbench.renderers.swt.MenuManagerRenderer.processAddition(MenuManagerRenderer.java:554)
    at org.eclipse.e4.ui.workbench.renderers.swt.MenuManagerRenderer.generateContributions(MenuManagerRenderer.java:529)
    at org.eclipse.e4.ui.workbench.renderers.swt.MenuManagerRenderer.processContributions(MenuManagerRenderer.java:494)
    at org.eclipse.ui.internal.PopupMenuExtender.addMenuContributions(PopupMenuExtender.java:409)
    at org.eclipse.ui.internal.PopupMenuExtender.menuAboutToShow(PopupMenuExtender.java:381)
    at org.eclipse.jface.action.MenuManager.fireAboutToShow(MenuManager.java:333)
    at org.eclipse.jface.action.MenuManager.handleAboutToShow(MenuManager.java:466)
    at org.eclipse.jface.action.MenuManager.access$1(MenuManager.java:461)
    at org.eclipse.jface.action.MenuManager$2.menuShown(MenuManager.java:493)
    at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:255)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4362)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1113)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1137)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1118)
    at org.eclipse.swt.widgets.Control.WM_INITMENUPOPUP(Control.java:5023)
    at org.eclipse.swt.widgets.Control.windowProc(Control.java:4691)
    at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:339)
    at org.eclipse.swt.widgets.Decorations.windowProc(Decorations.java:1633)
    at org.eclipse.swt.widgets.Shell.windowProc(Shell.java:2117)
    at org.eclipse.swt.widgets.Display.windowProc(Display.java:5050)
    at org.eclipse.swt.internal.win32.OS.TrackPopupMenu(Native Method)
    at org.eclipse.swt.widgets.Menu._setVisible(Menu.java:262)
    at org.eclipse.swt.widgets.Display.runPopups(Display.java:4221)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3763)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$4.run(PartRenderingEngine.java:1127)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:337)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1018)
    at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:156)
    at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:654)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:337)
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:598)
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
    at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:139)
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:380)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:235)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:669)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:608)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1515)
    at org.eclipse.equinox.launcher.Main.main(Main.java:1488)
Caused by: java.lang.NullPointerException
    at org.eclipse.ui.internal.commands.SlaveCommandService.registerElementForCommand(SlaveCommandService.java:311)
    at org.eclipse.ui.internal.commands.SlaveCommandService.registerElementForUpdate(SlaveCommandService.java:395)
    at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.fill(HandledContributionItem.java:324)
    at org.eclipse.jface.action.MenuManager.doItemFill(MenuManager.java:724)
    at org.eclipse.jface.action.MenuManager.update(MenuManager.java:806)
    at org.eclipse.jface.action.MenuManager.update(MenuManager.java:665)
    at org.eclipse.e4.ui.workbench.renderers.swt.MenuManagerRenderer.scheduleManagerUpdate(MenuManagerRenderer.java:1164)
    at org.eclipse.e4.ui.workbench.renderers.swt.MenuManagerRenderer.processContents(MenuManagerRenderer.java:636)
    at org.eclipse.e4.ui.workbench.renderers.swt.MenuManagerRenderer.subscribeTopicChildAdded(MenuManagerRenderer.java:313)
    at sun.reflect.GeneratedMethodAccessor20.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:56)
    ... 68 more

Answer 1

I think this is because you are specifying the wrong id for your mandatory command parameter.

In org.eclipse.ui.commands you declare the parameter as

 <commandParameter
        id="FeatureType"
        name="feature type"
        optional="false"

so the id is FeatureType

but in org.eclipse.ui.menus you use:

<parameter name="Type" value="ViewThis"/>

the name does match.