javafe.filespace
Class HashTree

java.lang.Object
  javafe.filespace.Tree
      javafe.filespace.HashTree

Direct Known Subclasses:

ExtTree, PreloadedTree

abstract class HashTree

extends Tree

A HashTree is a Tree that uses a Hashtable to store the map between labels and its direct children.

This abstract class leaves how the Hashtable should be filled up to its subclasses.

Field Summary

protected java.util.Hashtable

edges The mapping between our outgoing edge's labels and the subTrees they point to.

Fields inherited from class javafe.filespace.Tree

data

Constructor Summary

	HashTree(java.lang.Object data) Create a root node:
protected	HashTree(Tree parent, java.lang.String label, java.lang.Object data) Create a non-root node:

Method Summary

java.util.Enumeration	children() An enumeration of this node's direct children.
Tree	getChild(java.lang.String label) Fetch our direct child along the edge labelled label.

Methods inherited from class javafe.filespace.Tree

getChildrenCount, getLabel, getParent, getQualifiedChild, getQualifiedName, getRootNode, getSimpleName, isLeaf, print, printDetails

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

edges

protected java.util.Hashtable edges

The mapping between our outgoing edge's labels and the subTrees they point to. No entry for a label means no edge with that label exists.

Invariant: all elements of edges are Trees and all keys are Strings.

Constructor Detail

HashTree

public HashTree(java.lang.Object data)

Create a root node:

HashTree

protected HashTree(Tree parent,
                   java.lang.String label,
                   java.lang.Object data)

Create a non-root node:

Method Detail

children

public java.util.Enumeration children()

An enumeration of this node's direct children. Each child occurs exactly once in the enumeration. The order is unspecified and may differ from call to call.

Note: The Objects returned by the resulting enumeration's nextElement method are guaranteed to be of type Tree and non-null.

Specified by:

children in class Tree

getChild

public Tree getChild(java.lang.String label)

Fetch our direct child along the edge labelled label. Iff there is no such child, return null.

Overrides:

getChild in class Tree