Activate the cursor node (e.g. emit an activation event).
Clear all selection.
Collapse the cursor node.
Whether the cursor node has children (is expandable).
Expand the cursor node.
Whether any node currently has the keyboard cursor.
Whether the cursor node is currently expanded.
Move cursor to the next visible node.
Move cursor to the first visible node.
Move cursor to the last visible node.
Move cursor to the parent of the current node.
Move cursor to the previous visible node.
Delegate interface that the TreeKeyboardHandler uses to query and navigate the tree-view's state.
All navigation and selection logic lives in the delegate (the component). The handler is just a thin key-to-intent mapper.
Implement this on the host component (or any adapter) to wire up the handler without coupling it to a specific component class.