wt.visitor
Class BasicWalker

java.lang.Object
  wt.visitor.BasicWalker

All Implemented Interfaces:

Walker

Direct Known Subclasses:

Navigator

public abstract class BasicWalker

extends Object

implements Walker

This abstract class is an implementation which provides some basic functionality for sub-class use.

Descendant classes are responsible for maintaining a list of nodes that have been visited. This is used to pass a flag to the Visitor's visit operation. As a convenience, registerVisitedNode() and clearVisitedNodes() methods are implemented in this base class.

Supported API: false

Extendable: false

Field Summary

private static String	CLASSNAME
private NodeExpander	nodeExpander
private Hashtable	nodes
private boolean	recursionDetectionEnabled The notion of recursion detection is established here.
private static String	RESOURCE
private Visitor	visitor

Fields inherited from interface wt.visitor.Walker

NODE_EXPANDER, VISITOR

Constructor Summary

BasicWalker()

Method Summary

protected void	clearVisitedNodes() This method clears the internal registration of nodes that were visited.
NodeExpander	getNodeExpander() Gets the object for the association that plays role: nodeExpander.
Visitor	getVisitor() Gets the object for the association that plays role: visitor.
boolean	isRecursionDetectionEnabled()
private void	nodeExpanderValidate(NodeExpander a_NodeExpander)
protected boolean	registerVisitedNode(ObjectIdentifier a_object) This method registers the node as visited.
void	setNodeExpander(NodeExpander a_NodeExpander) Sets the object for the association that plays role: nodeExpander.
void	setRecursionDetectionEnabled(boolean enable)
void	setVisitor(Visitor a_Visitor) Sets the object for the association that plays role: visitor.
private void	visitorValidate(Visitor a_Visitor)

Methods inherited from class java.lang.Object

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

Methods inherited from interface wt.visitor.Walker

traverse

Field Detail

RESOURCE

private static final String RESOURCE

See Also:

Constant Field Values

CLASSNAME

private static final String CLASSNAME

visitor

private Visitor visitor

nodeExpander

private NodeExpander nodeExpander

recursionDetectionEnabled

private boolean recursionDetectionEnabled

The notion of recursion detection is established here. This class defines the object necessary (PathNode) to validate, but requires the extenders (DFSWalker and BFSWalker) to use it correctly. Note that these classes must also implement appropriate behavior when recursion is disabled. The reason for not doing it here is that there's no need to even create the PathNodes if we're not doing detection; if we were to disable validatePath in the PathNode, we'd ultimately be creating a lot of objects that won't do anything.

nodes

private Hashtable nodes

Constructor Detail

BasicWalker

public BasicWalker()

Method Detail

registerVisitedNode

protected boolean registerVisitedNode(ObjectIdentifier a_object)

This method registers the node as visited. It returns true, if the node was previously registered.

Supported API: false

Parameters:

a_object -

Returns:

boolean

clearVisitedNodes

protected void clearVisitedNodes()

This method clears the internal registration of nodes that were visited.

Supported API: false

getVisitor

public Visitor getVisitor()

Gets the object for the association that plays role: visitor.

Supported API: false

Specified by:

getVisitor in interface Walker

Returns:

Visitor

setVisitor

public void setVisitor(Visitor a_Visitor)
                throws WTPropertyVetoException

Sets the object for the association that plays role: visitor.

Supported API: false

Specified by:

setVisitor in interface Walker

Parameters:

a_Visitor -

Throws:

WTPropertyVetoException

visitorValidate

private void visitorValidate(Visitor a_Visitor)
                      throws WTPropertyVetoException

Parameters:

a_Visitor -

Throws:

WTPropertyVetoException

getNodeExpander

public NodeExpander getNodeExpander()

Gets the object for the association that plays role: nodeExpander.

Supported API: false

Specified by:

getNodeExpander in interface Walker

Returns:

NodeExpander

setNodeExpander

public void setNodeExpander(NodeExpander a_NodeExpander)
                     throws WTPropertyVetoException

Sets the object for the association that plays role: nodeExpander.

Supported API: false

Specified by:

setNodeExpander in interface Walker

Parameters:

a_NodeExpander -

Throws:

WTPropertyVetoException

nodeExpanderValidate

private void nodeExpanderValidate(NodeExpander a_NodeExpander)
                           throws WTPropertyVetoException

Parameters:

a_NodeExpander -

Throws:

WTPropertyVetoException

isRecursionDetectionEnabled

public boolean isRecursionDetectionEnabled()

setRecursionDetectionEnabled

public void setRecursionDetectionEnabled(boolean enable)