mwalk.visitor
Class CollapseVisitor

java.lang.Object
  |
  +--mwalk.visitor.AbstractVisitor
        |
        +--mwalk.visitor.CollapseVisitor

public class CollapseVisitor

extends AbstractVisitor

implements DownVisitor

A visitor that collapses the primary tree based on matching data at each node. The type of data referenced can be specified in the config file.

Version:

1.0

Author:

Robert Chalmers

Field Summary

private static java.lang.String	CFG_BASE Base of keys in configuration file
protected java.lang.String	type Type of data - used as node's hash key

Fields inherited from class mwalk.visitor.AbstractVisitor

CFG_BASE, eval, seen, verbose

Constructor Summary

CollapseVisitor()
Default constructor.

Method Summary

TreeNode[]	getChildren(Tree tree, TreeNode node) Retrieve the list of children of this node.
boolean	init(Tree tree) Initialize the visitor state.
boolean	postfix() Whether to visit after visiting parent/children.
protected void	transfer(TreeNode src, TreeNode dst) Transfer children from one node to another.
java.lang.Object	visitDown(Tree tree, TreeNode node, java.util.Vector list) Visit the current node after visiting children.

Methods inherited from class mwalk.visitor.AbstractVisitor

again, cfgBoolean, cfgInt, cfgString, cfgVisitor, evaluator, evaluator, getParents, getReceivers, haveSeen, haveVisited, markSeen, markVisited, nextReceiver, prefix, reset, verbose, visitDown, visitUp, visitUp, walkDown, walkUp

Methods inherited from class java.lang.Object

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

Field Detail

CFG_BASE

private static final java.lang.String CFG_BASE

Base of keys in configuration file

type

protected java.lang.String type

Type of data - used as node's hash key

Constructor Detail

CollapseVisitor

public CollapseVisitor()

Default constructor.

Method Detail

postfix

public boolean postfix()

Whether to visit after visiting parent/children.

Overrides:

postfix in class AbstractVisitor

Returns:

boolean whether to visit after

init

public boolean init(Tree tree)

Initialize the visitor state.

Overrides:

init in class AbstractVisitor

Parameters:

Tree - current tree instance

Returns:

boolean whether to walk again

transfer

protected void transfer(TreeNode src,
                        TreeNode dst)

Transfer children from one node to another.

Parameters:

TreeNode - node to transfer from

TreeNode - node to transfer to

visitDown

public java.lang.Object visitDown(Tree tree,
                                  TreeNode node,
                                  java.util.Vector list)
                           throws VisitException

Visit the current node after visiting children. This method is called if postfix() returns true.

Specified by:

visitDown in interface DownVisitor

Overrides:

visitDown in class AbstractVisitor

Parameters:

Tree - current tree instance

TreeNode - current node

Object - list of return values passed back along the path

Returns:

Object optional return value to pass back along the path

Throws:

VisitException - if a problem ocurred during visit

getChildren

public TreeNode[] getChildren(Tree tree,
                              TreeNode node)

Retrieve the list of children of this node.

Specified by:

getChildren in interface DownVisitor

Overrides:

getChildren in class AbstractVisitor

Parameters:

Tree - vistited tree

TreeNode - currently visited node

Returns:

TreeNode[] array of child nodes of currently visited node