ESC/Java2
© 2003,2004,2005 David Cok and Joseph Kiniry
© 2005 UCD Dublin
© 2003,2004 Radboud University Nijmegen
© 1999,2000 Compaq Computer Corporation
© 1997,1998,1999 Digital Equipment Corporation
All Rights Reserved

javafe.filespace
Class ExtTree

java.lang.Object
  extended byjavafe.filespace.Tree
      extended byjavafe.filespace.HashTree
          extended byjavafe.filespace.ExtTree
Direct Known Subclasses:
ZipTree

class ExtTree
extends HashTree

A ExtTree is a HashTree that starts out as just a root node, but may be extended at any time by (recursively) adding children.

Edges and nodes cannot be deleted once added, however.


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
  ExtTree(java.lang.Object data)
          Create a root node:
protected ExtTree(Tree parent, java.lang.String label, java.lang.Object data)
          Create a non-root node:
 
Method Summary
 ExtTree addChild(java.lang.String label, java.lang.Object newData)
          Create a new direct child of us with label label and data newData.
 ExtTree addPath(java.lang.String[] path)
          This is an extended version of addChild that takes a path (a list of labels) instead of a single label.
 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

ExtTree

public ExtTree(java.lang.Object data)
Create a root node:


ExtTree

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

Method Detail

addChild

public ExtTree addChild(java.lang.String label,
                        java.lang.Object newData)
Create a new direct child of us with label label and data newData. The new child will have no direct children.

If a child by the name of label already exists, then this routine leaves the tree unchanged.

In either case, the (resulting) child with label label is returned.


addPath

public ExtTree addPath(java.lang.String[] path)
This is an extended version of addChild that takes a path (a list of labels) instead of a single label. It returns the child located by following path from this node. It creates any necessary nodes along the way using addChild with null for newData. Path must be non-null.


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

ESC/Java2
© 2003,2004,2005 David Cok and Joseph Kiniry
© 2005 UCD Dublin
© 2003,2004 Radboud University Nijmegen
© 1999,2000 Compaq Computer Corporation
© 1997,1998,1999 Digital Equipment Corporation
All Rights Reserved

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