saffron.util
Class Walker

java.lang.Object
  |
  +--saffron.util.Walker

All Implemented Interfaces:

Enumeration

public class Walker

extends Object

implements Enumeration

Walks over a tree, returning nodes in prefix order. Objects which are an instance of Walkable supply their children using getChildren(); other objects are assumed to have no children. Do not modify the tree during the enumeration. Example use: Tree t; Walker w = new Walker(t); while (w.hasMoreElements()) { Tree node = (Tree) w.nextNode(); System.out.println(node.toString()); }

Nested Class Summary

(package private) class	Walker.Frame
private static class	Walker.Region

Field Summary

(package private) Walker.Frame	currentFrame
(package private) Object	nextNode
(package private) Stack	stack

Constructor Summary

Walker(Walkable root)

Method Summary

private static int	arrayFind(Object[] array, Object o)
Object	currentElement() returns the current object.
Object	getAncestor(int iDepth)
private Walker.Frame	getAncestorFrame(int iDepth) returns the iDepthth ancestor of the current element
int	getAncestorOrdinal(int iDepth) get the ordinal within its parent node of the iDepthth ancestor.
Object[]	getChildren(Object node) Override this function to prune the tree, or to allow objects which are not Walkable to have children.
int	getOrdinal() get the ordinal within its parent node of the current node.
Object	getParent()
boolean	hasMoreElements()
int	level() returns level in the tree of the current element (that is, last element returned from nextElement()).
static void	main(String[] args)
private void	moveToNext()
Object	nextElement()
void	prune() Tell walker that we don't want to visit any (more) children of this node.
void	pruneSiblings()
private void	visit(Walker.Frame parent, Object node)

Methods inherited from class java.lang.Object

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

Field Detail

stack

Stack stack

currentFrame

Walker.Frame currentFrame

nextNode

Object nextNode

Constructor Detail

Walker

public Walker(Walkable root)

Method Detail

moveToNext

private void moveToNext()

visit

private void visit(Walker.Frame parent,
                   Object node)

hasMoreElements

public boolean hasMoreElements()

Specified by:

hasMoreElements in interface Enumeration

nextElement

public Object nextElement()

Specified by:

nextElement in interface Enumeration

prune

public void prune()

Tell walker that we don't want to visit any (more) children of this node. The next node visited will be (a return visit to) the node's parent. Not valid until nextElement() has been called.

pruneSiblings

public void pruneSiblings()

currentElement

public Object currentElement()

returns the current object. Not valid until nextElement() has been called.

level

public int level()

returns level in the tree of the current element (that is, last element returned from nextElement()). The level of the root element is 0.

getParent

public final Object getParent()

getAncestor

public final Object getAncestor(int iDepth)

getAncestorFrame

private Walker.Frame getAncestorFrame(int iDepth)

returns the iDepthth ancestor of the current element

getOrdinal

public int getOrdinal()

get the ordinal within its parent node of the current node. Returns 0 for the root element. Equivalent to getAncestorOrdinal(0).

getAncestorOrdinal

public int getAncestorOrdinal(int iDepth)

get the ordinal within its parent node of the iDepthth ancestor.

getChildren

public Object[] getChildren(Object node)

Override this function to prune the tree, or to allow objects which are not Walkable to have children.

arrayFind

private static int arrayFind(Object[] array,
                             Object o)

main

public static void main(String[] args)