public void addSelectedFilesToTargetList() {
    ISelection selection = sourceFileViewer.getSelection();

    if (isValidSourceFileViewerSelection(selection)) {
      java.util.List list = null;
      if (selection instanceof IStructuredSelection) {
        list = ((IStructuredSelection) selection).toList();

        if (list != null) {
          list = ((IStructuredSelection) selection).toList();
          for (Iterator i = list.iterator(); i.hasNext(); ) {
            IResource resource = (IResource) i.next();
            if (resource instanceof IFile) {
              // Check if its in the list. Don't add it if it is.
              String resourceName = resource.getFullPath().toString();
              if (selectedListBox.indexOf(resourceName) == -1) selectedListBox.add(resourceName);
            }
          }
          setFiles(selectedListBox.getItems());
        }

        setAddButtonEnabled(false);

        if (selectedListBox.getItemCount() > 0) {
          removeAllButton.setEnabled(true);
          if (isFileMandatory) setPageComplete(true);
          if (selectedListBox.getSelectionCount() > 0) setRemoveButtonEnabled(true);
          else setRemoveButtonEnabled(false);
        }
      }
    }
  }
 public boolean checkIfFileInTarget(IFile fileToCheck) {
   String[] strings = selectedListBox.getItems();
   int size = selectedListBox.getItemCount();
   for (int i = 0; i < size; i++) {
     if (strings[i].compareTo(fileToCheck.getFullPath().toString()) == 0) return true;
   }
   return false;
 }
  private void createSelectedListBox(Composite parent) {
    selectedListBox = new List(parent, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL | SWT.BORDER);
    selectedListBox.addSelectionListener(
        new SelectionListener() {
          public void widgetDefaultSelected(SelectionEvent event) {}

          public void widgetSelected(SelectionEvent event) {

            if (selectedListBox.getSelectionCount() > 0) setRemoveButtonEnabled(true);
            else setRemoveButtonEnabled(false);
            return;
          }
        });

    GridData gd = new GridData(GridData.FILL_BOTH);
    gd.widthHint = SIZING_LISTS_WIDTH;
    gd.heightHint = SIZING_LISTS_HEIGHT;
    selectedListBox.setLayoutData(gd);
  }