private DesignerGraphicalEditorPart editor;

    private PageBook pageBook;

    private Control treeview;

    private Canvas overview;

    private Thumbnail thumbnail;

    //private IAction moveItemUpAction;

    private IAction showOverviewAction;

    private IAction showTreeviewAction;

    public OutlineViewer(DesignerGraphicalEditorPart editor) {

        super(new TreeViewer());

        this.editor = editor;

    }

    @Override

    public void createControl(Composite parent) {

        createToolBar();

        createPageBook(parent);

        getSite().getWorkbenchWindow().getSelectionService().addSelectionListener(this);

    }

    @Override

    public void dispose() {

        if (null != thumbnail) {

            thumbnail.deactivate();

        }

        getSite().getWorkbenchWindow().getSelectionService().removeSelectionListener(this);

        super.dispose();

    }

    public void selectionChanged(IWorkbenchPart part, ISelection selection) {

        if (!(selection instanceof IStructuredSelection)) {

            return;

        }

        IStructuredSelection structuredSelection = (IStructuredSelection) selection;

        Object selectedObject = structuredSelection.getFirstElement();

        if (!(selectedObject instanceof EditPart))

            return;

        EditPart source = (EditPart) selectedObject;

        select((GraphElement) source.getModel());

    }

   

    public void select(GraphElement element) {

        EditPart target = (EditPart) getViewer().getEditPartRegistry().get(element);

        if (target != null) {

            getViewer().select(target);

        }

    }

    private void createToolBar() {

        IToolBarManager tbm = getSite().getActionBars().getToolBarManager();

        //createMoveItemUpAction(tbm);

        createShowOverviewAction(tbm);

        createShowTreeviewAction(tbm);

    }

    private void createShowOverviewAction(IToolBarManager tbm) {

        showOverviewAction = new Action() {

            @Override

            public void run() {

                showOverview();

            }

        };

        showOverviewAction.setImageDescriptor(SharedImages.getImageDescriptor("icons/overview.gif"));

        tbm.add(showOverviewAction);

    }

    /*

    private GraphElement getModelSelection() {

        AbstractTreeEditPart selectedEditPart = (AbstractTreeEditPart) ((IStructuredSelection) getViewer().getSelection()).getFirstElement();

        if (selectedEditPart == null) {

            return null;

        }

        return (GraphElement) selectedEditPart.getModel();

    }

    private void updateUpButton() {

        GraphElement selection = getModelSelection();

        if (selection == null || selection.getParent() == null) {

            moveItemUpAction.setEnabled(false);

        } else {

            List<? extends GraphElement> children = selection.getParent().getChildren(selection.getClass());

            moveItemUpAction.setEnabled(children.indexOf(selection) > 0);

        }

    }

    private void createMoveItemUpAction(IToolBarManager tbm) {

        getViewer().addSelectionChangedListener(new ISelectionChangedListener() {

            public void selectionChanged(SelectionChangedEvent event) {

                updateUpButton();

            }

        });

        moveItemUpAction = new Action() {

            @Override

            public void run() {

                IStructuredSelection structuredSelection = (IStructuredSelection) getViewer().getSelection();

                AbstractTreeEditPart selectedEditPart = (AbstractTreeEditPart) structuredSelection.getFirstElement();

                GraphElement selection = (GraphElement) selectedEditPart.getModel();

                List<? extends GraphElement> children = selection.getParent().getChildren(selection.getClass());

                int index = children.indexOf(selection);

                selection.getParent().swapChilds(selection, children.get(index-1));

                getViewer().select(selectedEditPart);

            }

        };

        moveItemUpAction.setEnabled(false);

        moveItemUpAction.setImageDescriptor(SharedImages.getImageDescriptor("icons/up.gif"));

        tbm.add(moveItemUpAction);

    }

    */

    private void showOverview() {

        showTreeviewAction.setChecked(false);

        showOverviewAction.setChecked(true);

        pageBook.showPage(overview);

        thumbnail.setVisible(true);

    }

    private void createShowTreeviewAction(IToolBarManager tbm) {

        showTreeviewAction = new Action() {

            @Override

            public void run() {

                showTreeview();

            }

        };

        showTreeviewAction.setImageDescriptor(SharedImages.getImageDescriptor("icons/treeview.gif"));

        tbm.add(showTreeviewAction);

    }

    private void showTreeview() {

        showTreeviewAction.setChecked(true);

        showOverviewAction.setChecked(false);

        pageBook.showPage(treeview);

        thumbnail.setVisible(false);

    }

    private void createPageBook(Composite parent) {

        pageBook = new PageBook(parent, SWT.NONE);

        createTreeview(pageBook);

        createOverview(pageBook);

        showTreeview();

    }

    private void createOverview(Composite parent) {

        ScalableFreeformRootEditPart rootEditPart = (ScalableFreeformRootEditPart) editor.getGraphicalViewer().getRootEditPart();

        overview = new Canvas(parent, SWT.NONE);

        LightweightSystem lws = new LightweightSystem(overview);

        thumbnail = new ScrollableThumbnail((Viewport) rootEditPart.getFigure());

        thumbnail.setBorder(new MarginBorder(3));

        thumbnail.setSource(rootEditPart.getLayer(LayerConstants.PRINTABLE_LAYERS));

        lws.setContents(thumbnail);

    }

    private void createTreeview(Composite parent) {

        treeview = getViewer().createControl(parent);

        getSite().setSelectionProvider(getViewer());

        //getViewer().setContextMenu(createContextMenu());

        getViewer().setEditDomain(editor.getEditDomain());

        getViewer().setEditPartFactory(new GPDEditPartFactory());

        getViewer().setContents(editor.getEditor().getDefinition());

    }

    /*

    private MenuManager createContextMenu() {

        MenuManager menuManager = new OutlineContextMenuProvider(getViewer());

        getSite().registerContextMenu("org.jbpm.ui.outline.contextmenu", menuManager, getViewer());

        return menuManager;

    }

    private class OutlineContextMenuProvider extends ContextMenuProvider {

        public OutlineContextMenuProvider(EditPartViewer viewer) {

            super(viewer);

        }

        @Override

        public void buildContextMenu(IMenuManager menu) {

            menu.add(new Separator(IWorkbenchActionConstants.MB_ADDITIONS));

        }

    }

    */

        private boolean firstTime = true;

        public EditPart createEditPart(EditPart context, Object model) {

            if (firstTime && model instanceof ProcessDefinition) {

                firstTime = false;

                EditPart rootEditPart = new OutlineRootTreeEditPart();

                rootEditPart.setModel(model);

                return rootEditPart;

            }

            GraphElement element = (GraphElement) model;

            if (element instanceof Variable) {

                return new VariableTreeEditPart((Variable) element);

            }

            if (element instanceof GroupElement) {

                return new GroupElementTreeEditPart((GroupElement) element);

            }

            return element.getTypeDefinition().createTreeEditPart(element);

        }

    }

    public CommandStack getCommandStack() {

        return editor.getCommandStack();

    }

    @Override

    public Control getControl() {

        return pageBook;

    }

}