Get the parent of an IStructuredSelection (eclipse-rcp)?

Question

I have a TreeViewer in a view and need to get the parent (if it exists) of an item selected. Nothing seems to work and google yields no answers..

mBacktestTree.addDoubleClickListener(new IDoubleClickListener() {
          public void doubleClick(DoubleClickEvent event) {
       IWorkbenchPage page = getSite().getPage();
       TreeViewer tree = (TreeViewer) event.getSource();
       Object selectObject = ((IStructuredSelection) tree.getSelection()).getFirstElement();

// now how can I get the parent of selectObject?

Answer 1

You can get the parent from an ITreeSelection. E.g.

public class DirectoryView extends ViewPart 
{
    public void createPartControl(Composite parent) 
    {
     TreeViewer treeViewer = new TreeViewer(parent);
     treeViewer.setContentProvider(new DirectoryProvider());
     treeViewer.setInput(new File(System.getProperty("user.home"))); 
     treeViewer.addDoubleClickListener(new IDoubleClickListener() 
     {                    
      public void doubleClick(DoubleClickEvent event) 
      {
       ITreeSelection selection = ((ITreeSelection)event.getSelection());
       System.out.println(selection.getPaths()[0].getParentPath().getLastSegment());
      }
     });
    } 

    class DirectoryProvider implements ITreeContentProvider
    {
     public Object[] getChildren(Object parentElement) 
     {
      File[] folders = ((File) parentElement).listFiles();
      return folders == null ? new File[0] : folders;
     }

     public Object getParent(Object element) 
     {
      return ((File) element).getParent();
     }

     public boolean hasChildren(Object element) 
     {
      return getChildren(element).length >0;
     }

     public Object[] getElements(Object inputElement) 
     {
      return getChildren(inputElement);
     }

     public void dispose() 
     {
      // ignore
     }

     public void inputChanged(Viewer viewer, Object oldInput, Object newInput) 
     {
      // ignore
     }
    }

    public void setFocus() 
    {
     // ignore
    }
}

Answer 2

You can also obtain the parent from your tree content provider:

mBacktestTree.addDoubleClickListener(new IDoubleClickListener() {
                    public void doubleClick(DoubleClickEvent event) {
                            IWorkbenchPage page = getSite().getPage();
                            TreeViewer tree = (TreeViewer) event.getSource();
                            Object selectObject = ((IStructuredSelection)tree.getSelection()).getFirstElement();

ITreeContentProvider tcp =tree.getContentProvider();
Object parent = tcp.getParent(selectObject);