Package org.apache.jorphan.collections

Interface HashTreeTraverser

All Known Implementing Classes:
CheckDirty, ComponentTreeClonerForValidation, ConvertListeners, FindTestElementsUpToRootTraverser, PreCompiler, SearchByClass, TestCompiler, TreeCloner, TreeClonerForValidation, TreeClonerNoTimer, TurnElementsOn
public interface HashTreeTraverser
By implementing this interface, a class can easily traverse a HashTree object, and be notified via callbacks of certain events. There are three such events:
  1. When a node is first encountered, the traverser's addNode(Object,HashTree) method is called. It is handed the object at that node, and the entire sub-tree of the node.
  2. When a leaf node is encountered, the traverser is notified that a full path has been finished via the processPath() method. It is the traversing class's responsibility to know the path that has just finished (this can be done by keeping a simple stack of all added nodes).
  3. When a node is retraced, the traverser's subtractNode() is called. Again, it is the traverser's responsibility to know which node has been retraced.
To summarize, as the traversal goes down a tree path, nodes are added. When the end of the path is reached, the processPath() call is sent. As the traversal backs up, nodes are subtracted.

The traversal is a depth-first traversal.

See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    addNode(Object node, HashTree subTree)
    The tree traverses itself depth-first, calling addNode for each object it encounters as it goes.
    void
    processPath()
    Process path is called when a leaf is reached.
    void
    subtractNode()
    Indicates traversal has moved up a step, and the visitor should remove the top node from its stack structure.

  • Method Details

    • addNode

      void addNode(Object node, HashTree subTree)
      The tree traverses itself depth-first, calling addNode for each object it encounters as it goes. This is a callback method, and should not be called except by a HashTree during traversal.
      Parameters:
      node - the node currently encountered
      subTree - the HashTree under the node encountered

    • subtractNode

      void subtractNode()
      Indicates traversal has moved up a step, and the visitor should remove the top node from its stack structure. This is a callback method, and should not be called except by a HashTree during traversal.

    • processPath

      void processPath()
      Process path is called when a leaf is reached. If a visitor wishes to generate Lists of path elements to each leaf, it should keep a Stack data structure of nodes passed to it with addNode, and removing top items for every subtractNode() call. This is a callback method, and should not be called except by a HashTree during traversal.