protected void installKeyboardActions()

in flutter-idea/src/io/flutter/view/InspectorTreeUI.java [153:236]
70 lines of code
21 McCabe index (conditional complexity)

  protected void installKeyboardActions() {
    super.installKeyboardActions();

    if (Boolean.TRUE.equals(tree.getClientProperty("MacTreeUi.actionsInstalled"))) return;

    tree.putClientProperty("MacTreeUi.actionsInstalled", Boolean.TRUE);

    final InputMap inputMap = tree.getInputMap(JComponent.WHEN_FOCUSED);
    inputMap.put(KeyStroke.getKeyStroke("pressed LEFT"), "collapse_or_move_up");
    inputMap.put(KeyStroke.getKeyStroke("pressed RIGHT"), "expand");

    final ActionMap actionMap = tree.getActionMap();

    final Action expandAction = actionMap.get("expand");
    if (expandAction != null) {
      actionMap.put("expand", new TreeUIAction() {
        @Override
        public void actionPerformed(ActionEvent e) {
          final Object source = e.getSource();
          if (source instanceof JTree) {
            final JTree tree = (JTree)source;
            final int selectionRow = tree.getLeadSelectionRow();
            if (selectionRow != -1) {
              final TreePath selectionPath = tree.getPathForRow(selectionRow);
              if (selectionPath != null) {
                final boolean leaf = tree.getModel().isLeaf(selectionPath.getLastPathComponent());
                int toSelect = -1;
                int toScroll = -1;
                if (leaf || tree.isExpanded(selectionRow)) {
                  if (selectionRow + 1 < tree.getRowCount()) {
                    toSelect = selectionRow + 1;
                    toScroll = toSelect;
                  }
                }
                //todo[kb]: make cycle scrolling

                if (toSelect != -1) {
                  tree.setSelectionInterval(toSelect, toSelect);
                }

                if (toScroll != -1) {
                  tree.scrollRowToVisible(toScroll);
                }

                if (toSelect != -1 || toScroll != -1) return;
              }
            }
          }


          expandAction.actionPerformed(e);
        }
      });
    }

    actionMap.put("collapse_or_move_up", new TreeUIAction() {
      @Override
      public void actionPerformed(final ActionEvent e) {
        final Object source = e.getSource();
        if (source instanceof JTree) {
          final JTree tree = (JTree)source;
          final int selectionRow = tree.getLeadSelectionRow();
          if (selectionRow == -1) return;

          final TreePath selectionPath = tree.getPathForRow(selectionRow);
          if (selectionPath == null) return;

          if (tree.getModel().isLeaf(selectionPath.getLastPathComponent()) || tree.isCollapsed(selectionRow)) {
            final TreePath parentPath = tree.getPathForRow(selectionRow).getParentPath();
            if (parentPath != null) {
              if (parentPath.getParentPath() != null || tree.isRootVisible()) {
                final int parentRow = tree.getRowForPath(parentPath);
                tree.scrollRowToVisible(parentRow);
                tree.setSelectionInterval(parentRow, parentRow);
              }
            }
          }
          else {
            tree.collapseRow(selectionRow);
          }
        }
      }
    });
  }