TreeWalker (repo API)

All Known Implementing Classes:

ParentAfterChildrenWalker
```
public interface TreeWalker
```
Provides a method to walk through a tree of Nodes. The order of visiting the nodes is defined by the implementation.
The walk(Node, NodeCallback) method allows to provide callbacks which allows to perform actions at certain moments of the walk-through. The moment when a callback is called depends of the interfaces that are implemented by a specific callback. Possible callbacks and their purposes are:
- EveryNodeCallback: The single method of this callback will be called once for every node in the tree in the order of the walkthrough.
- BottomNodeCallback: The single method of this callback will be called for every node in the tree, which is a bottom node (has no children).
- SkipNodeAndSubTreesCallback: The method of this callback is called before a node (or its children) are visited. Its sole method can return a boolean flag. If the callback returns true, then the node (and all the subtree starting from there) is skipped. If false is returned, the sub tree is processed normally.
- StepUpCallback: The sole method of this callback is called when some children of a node were visited and before the actual node is visited.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`walk(Node startingNode, NodeCallback callback)`	Walks through the tree starting from the given node and calls back on every node to the given callback

- Method Detail
  - walk
```
void walk(Node startingNode,
          NodeCallback callback)
```
    Walks through the tree starting from the given node and calls back on every node to the given callback
    
    Parameters:
    
    startingNode - the node where to start walking
    
    callback - the callback to call on each node