org.apache.pig.newplan.logical.rules
Class ImplicitSplitInserter

java.lang.Object
  org.apache.pig.newplan.optimizer.Rule
      org.apache.pig.newplan.logical.rules.ImplicitSplitInserter

public class ImplicitSplitInserter
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.

Nested Class Summary

class

ImplicitSplitInserter.ImplicitSplitInserterTransformer

Field Summary

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

currentPlan, log, name, pattern

Constructor Summary

ImplicitSplitInserter(String n)

Method Summary

protected OperatorPlan	buildPattern() Build the pattern that this rule will look for
Transformer	getNewTransformer() Get the transformer for this rule.
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, getPattern, isMandatory, isSkipListener, setSkipListener

Methods inherited from class java.lang.Object

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

Constructor Detail

ImplicitSplitInserter

public ImplicitSplitInserter(String n)

Method Detail

match

public List<OperatorPlan> match(OperatorPlan plan)
                         throws FrontendException

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.

Throws:

FrontendException

getNewTransformer

public Transformer getNewTransformer()

Description copied from class: Rule

Get the transformer for this rule. Abstract because the rule may want to choose how to instantiate the transformer. This should never return a cached transformer, it should always return a fresh one with no state.

Specified by:

getNewTransformer in class Rule

Returns:

Transformer to use with this rule

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