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

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

All Implemented Interfaces:

Visitor

public class ReferencedTablesVisitor
extends java.lang.Object
implements Visitor

Build a JBitSet of all of the referenced tables in the tree.

Field Summary

private JBitSet

tableMap

Constructor Summary

ReferencedTablesVisitor(JBitSet tableMap)

Method Summary

(package private) JBitSet	getTableMap()
boolean	skipChildren(Visitable node) No need to go below a Predicate or ResultSet.
boolean	stopTraversal() Method that is called to see if query tree traversal should be stopped before visiting all nodes.
Visitable	visit(Visitable node) Don't do anything unless we have a ColumnReference, Predicate or ResultSetNode node.
boolean	visitChildrenFirst(Visitable node) Method that is called to see if visit() should be called on the children of node before it is called on node itself.

Methods inherited from class java.lang.Object

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

Field Detail

tableMap

private JBitSet tableMap

Constructor Detail

ReferencedTablesVisitor

public ReferencedTablesVisitor(JBitSet tableMap)

Method Detail

visit

public Visitable visit(Visitable node)
                throws StandardException

Don't do anything unless we have a ColumnReference, Predicate or ResultSetNode node.

Specified by:

visit in interface Visitor

Parameters:

node - the node to process

Returns:

me

Throws:

StandardException - on error

skipChildren

public boolean skipChildren(Visitable node)

No need to go below a Predicate or ResultSet.

Specified by:

skipChildren in interface Visitor

Parameters:

node - the node to process

Returns:

Whether or not to go below the node.

visitChildrenFirst

public boolean visitChildrenFirst(Visitable node)

Description copied from interface: Visitor

Method that is called to see if visit() should be called on the children of node before it is called on node itself. If this method always returns true, the visitor will walk the tree bottom-up. If it always returns false, the tree is visited top-down.

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

stopTraversal

public boolean stopTraversal()

Description copied from interface: Visitor

Method that is called to see if query tree traversal should be stopped before visiting all nodes. Useful for short circuiting traversal if we already know we are done.

Specified by:

stopTraversal in interface Visitor

Returns:

true/false

getTableMap

JBitSet getTableMap()