org.apache.derby.impl.sql.compile
Class HasNodeVisitor

java.lang.Object
  org.apache.derby.impl.sql.compile.HasNodeVisitor

All Implemented Interfaces:

Visitor

Direct Known Subclasses:

HasTableFunctionVisitor

public class HasNodeVisitor
extends java.lang.Object
implements Visitor

Find out if we have a particular node anywhere in the tree. Stop traversal as soon as we find one.

Can find any type of node -- the class or class name of the target node is passed in as a constructor parameter.

Field Summary

protected boolean	hasNode
private java.lang.Class	nodeClass
private java.lang.Class	skipOverClass

Constructor Summary

HasNodeVisitor(java.lang.Class nodeClass)
Construct a visitor

HasNodeVisitor(java.lang.Class nodeClass, java.lang.Class skipOverClass)
Construct a visitor

Method Summary

boolean	hasNode() Indicate whether we found the node in question
void	reset() Reset the status so it can be run again.
boolean	skipChildren(Visitable node) Don't visit childen under the skipOverClass node, if it isn't null.
boolean	stopTraversal() Stop traversal if we found the target node
Visitable	visit(Visitable node) If we have found the target node, we are done.
boolean	visitChildrenFirst(Visitable node) Visit parent before children.

Methods inherited from class java.lang.Object

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

Field Detail

hasNode

protected boolean hasNode

nodeClass

private java.lang.Class nodeClass

skipOverClass

private java.lang.Class skipOverClass

Constructor Detail

HasNodeVisitor

public HasNodeVisitor(java.lang.Class nodeClass)

Construct a visitor

Parameters:

nodeClass - the class of the node that we are looking for.

HasNodeVisitor

public HasNodeVisitor(java.lang.Class nodeClass,
                      java.lang.Class skipOverClass)

Construct a visitor

Parameters:

nodeClass - the class of the node that we are looking for.

skipOverClass - do not go below this node when searching for nodeClass.

Method Detail

visit

public Visitable visit(Visitable node)

If we have found the target node, we are done.

Specified by:

visit in interface Visitor

Parameters:

node - the node to process

Returns:

me

stopTraversal

public boolean stopTraversal()

Stop traversal if we found the target node

Specified by:

stopTraversal in interface Visitor

Returns:

true/false

skipChildren

public boolean skipChildren(Visitable node)

Don't visit childen under the skipOverClass node, if it isn't null.

Specified by:

skipChildren in interface Visitor

Parameters:

node - the node to process

Returns:

true/false

visitChildrenFirst

public boolean visitChildrenFirst(Visitable node)

Visit parent before children.

Specified by:

visitChildrenFirst in interface Visitor

Parameters:

node - the top node of a sub-tree about to be visited

Returns:

true if node's children should be visited before node, false otherwise

hasNode

public boolean hasNode()

Indicate whether we found the node in question

Returns:

true/false

reset

public void reset()

Reset the status so it can be run again.