org.apache.pig.newplan.logical.rules

Class WholePlanRule

java.lang.Object

org.apache.pig.newplan.optimizer.Rule

org.apache.pig.newplan.logical.rules.WholePlanRule

Direct Known Subclasses:

AddForEach, ColumnMapKeyPrune

public abstract class WholePlanRule
extends Rule

Super class for all rules that operates on the whole plan. It doesn't look for a specific pattern. An example of such kind rule is ColumnPrune.

Field Summary

Fields inherited from class org.apache.pig.newplan.optimizer.Rule

currentPlan, log, name, pattern

Constructor Summary

Constructors

Constructor and Description
WholePlanRule(String n, boolean mandatory)

Method Summary

Modifier and Type	Method and Description
protected OperatorPlan	buildPattern() Build the pattern that this rule will look for
List<OperatorPlan>	match(OperatorPlan plan) Search for all the sub-plans that matches the pattern defined by this rule.

Methods inherited from class org.apache.pig.newplan.optimizer.Rule

getName, getNewTransformer, getPattern, isMandatory, isSkipListener, setSkipListener

Methods inherited from class java.lang.Object

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

Constructor Detail

WholePlanRule

public WholePlanRule(String n,
                     boolean mandatory)

Method Detail

match

public List<OperatorPlan> match(OperatorPlan plan)

Description copied from class: Rule

Search for all the sub-plans that matches the pattern defined by this rule. See class description above for limitations on the patterns supported.

Overrides:

match in class Rule

Parameters:

plan - the OperatorPlan to look for matches to the pattern

Returns:

A list of all matched sub-plans. The returned plans are partial views of the original OperatorPlan. Each is a sub-set of the original plan and represents the same topology as the pattern, but operators in the returned plan are the same objects as the original plan. Therefore, a call getPlan() from any node in the return plan would return the original plan.

buildPattern

protected OperatorPlan buildPattern()

Description copied from class: Rule

Build the pattern that this rule will look for

Specified by:

buildPattern in class Rule

Returns:

the pattern to look for by this rule