org.apache.hadoop.hive.ql.lib

Class ExpressionWalker

java.lang.Object

org.apache.hadoop.hive.ql.lib.DefaultGraphWalker

org.apache.hadoop.hive.ql.lib.ExpressionWalker

All Implemented Interfaces:

GraphWalker, SemanticGraphWalker

Direct Known Subclasses:

SubqueryExpressionWalker

public class ExpressionWalker
extends DefaultGraphWalker

class for traversing tree This class assumes that the given node represents TREE and not GRAPH i.e. there is only single path to reach a node

Field Summary

Fields inherited from class org.apache.hadoop.hive.ql.lib.DefaultGraphWalker

dispatcher, opQueue, opStack, retMap, toWalk

Constructor Summary

Constructors

Constructor and Description
ExpressionWalker(SemanticDispatcher disp) Constructor.

Method Summary

Modifier and Type	Method and Description
protected boolean	shouldByPass(Node childNode, Node parentNode)
protected void	walk(Node nd) walk the current operator and its descendants.

Methods inherited from class org.apache.hadoop.hive.ql.lib.DefaultGraphWalker

dispatch, dispatchAndReturn, getDispatchedList, startWalking

Methods inherited from class java.lang.Object

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

Constructor Detail

ExpressionWalker

public ExpressionWalker(SemanticDispatcher disp)

Constructor.

Parameters:

disp - dispatcher to call for each op encountered

Method Detail

shouldByPass

protected boolean shouldByPass(Node childNode,
                               Node parentNode)

walk

protected void walk(Node nd)
             throws SemanticException

walk the current operator and its descendants.

Overrides:

walk in class DefaultGraphWalker

Parameters:

nd - current operator in the tree

Throws:

SemanticException