org.apache.hadoop.hive.ql.lib

Class RuleRegExp

java.lang.Object

org.apache.hadoop.hive.ql.lib.RuleRegExp

All Implemented Interfaces:

Rule

public class RuleRegExp
extends Object
implements Rule

Rule interface for Nodes Used in Node dispatching to dispatch process/visitor functions for Nodes.

Constructor Summary

Constructors

Constructor and Description
RuleRegExp(String ruleName, String regExp) The rule specified by the regular expression.

Method Summary

Modifier and Type	Method and Description
int	cost(Stack<Node> stack) This function returns the cost of the rule for the specified stack.
String	getName()

Methods inherited from class java.lang.Object

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

Constructor Detail

RuleRegExp

public RuleRegExp(String ruleName,
                  String regExp)

The rule specified by the regular expression. Note that, the regular expression is specified in terms of Node name. For eg: TS.*RS -> means TableScan Node followed by anything any number of times followed by ReduceSink

Parameters:

ruleName - name of the rule

regExp - regular expression for the rule

Method Detail

cost

public int cost(Stack<Node> stack)
         throws SemanticException

This function returns the cost of the rule for the specified stack. Lower the cost, the better the rule is matched

Specified by:

cost in interface Rule

Parameters:

stack - Node stack encountered so far

Returns:

cost of the function

Throws:

SemanticException

getName

public String getName()

Specified by:

getName in interface Rule

Returns:

the name of the Node