org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators
Class POLimit

java.lang.Object
  org.apache.pig.impl.plan.Operator<PhyPlanVisitor>
      org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator
          org.apache.pig.backend.hadoop.executionengine.physicalLayer.relationalOperators.POLimit

All Implemented Interfaces:

Serializable, Cloneable, Comparable<Operator>, Illustrable

public class POLimit
extends PhysicalOperator

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator

alias, dummyBag, dummyBool, dummyDBA, dummyDouble, dummyFloat, dummyInt, dummyLong, dummyMap, dummyString, dummyTuple, illustrator, input, inputAttached, inputs, lineageTracer, outputs, parentPlan, pigLogger, reporter, requestedParallelism, res, resultType

Fields inherited from class org.apache.pig.impl.plan.Operator

mKey

Constructor Summary

POLimit(OperatorKey k)

POLimit(OperatorKey k, int rp)

POLimit(OperatorKey k, int rp, List<PhysicalOperator> inputs)

POLimit(OperatorKey k, List<PhysicalOperator> inputs)

Method Summary

POLimit	clone() Make a deep copy of this operator.
long	getLimit()
Result	getNext(Tuple t) Counts the number of tuples processed into static variable soFar, if the number of tuples processed reach the limit, return EOP; Otherwise, return the tuple
Tuple	illustratorMarkup(Object in, Object out, int eqClassIndex) input tuple mark up to be illustrate-able
String	name()
void	reset() Reset internal state in an operator.
void	setLimit(long limit)
boolean	supportsMultipleInputs() Indicates whether this operator supports multiple inputs.
boolean	supportsMultipleOutputs() Indicates whether this operator supports multiple outputs.
void	visit(PhyPlanVisitor v) Visit this node with the provided visitor.

Methods inherited from class org.apache.pig.backend.hadoop.executionengine.physicalLayer.PhysicalOperator

attachInput, cloneHelper, detachInput, getAlias, getAliasString, getDummy, getIllustrator, getInputs, getLogger, getNext, getNext, getNext, getNext, getNext, getNext, getNext, getNext, getNext, getNext, getPigLogger, getRequestedParallelism, getResultType, isAccumStarted, isAccumulative, isBlocking, isInputAttached, processInput, setAccumEnd, setAccumStart, setAccumulative, setAlias, setIllustrator, setInputs, setParentPlan, setPigLogger, setReporter, setRequestedParallelism, setResultType

Methods inherited from class org.apache.pig.impl.plan.Operator

compareTo, equals, getOperatorKey, getProjectionMap, hashCode, regenerateProjectionMap, rewire, toString, unsetProjectionMap

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

POLimit

public POLimit(OperatorKey k)

POLimit

public POLimit(OperatorKey k,
               int rp)

POLimit

public POLimit(OperatorKey k,
               List<PhysicalOperator> inputs)

POLimit

public POLimit(OperatorKey k,
               int rp,
               List<PhysicalOperator> inputs)

Method Detail

setLimit

public void setLimit(long limit)

getLimit

public long getLimit()

getNext

public Result getNext(Tuple t)
               throws ExecException

Counts the number of tuples processed into static variable soFar, if the number of tuples processed reach the limit, return EOP; Otherwise, return the tuple

Overrides:

getNext in class PhysicalOperator

Throws:

ExecException

name

public String name()

Specified by:

name in class Operator<PhyPlanVisitor>

supportsMultipleInputs

public boolean supportsMultipleInputs()

Description copied from class: Operator

Indicates whether this operator supports multiple inputs.

Specified by:

supportsMultipleInputs in class Operator<PhyPlanVisitor>

Returns:

true if it does, otherwise false.

supportsMultipleOutputs

public boolean supportsMultipleOutputs()

Description copied from class: Operator

Indicates whether this operator supports multiple outputs.

Specified by:

supportsMultipleOutputs in class Operator<PhyPlanVisitor>

Returns:

true if it does, otherwise false.

visit

public void visit(PhyPlanVisitor v)
           throws VisitorException

Description copied from class: Operator

Visit this node with the provided visitor. This should only be called by the visitor class itself, never directly.

Specified by:

visit in class PhysicalOperator

Parameters:

v - Visitor to visit with.

Throws:

VisitorException - if the visitor has a problem.

reset

public void reset()

Description copied from class: PhysicalOperator

Reset internal state in an operator. For use in nested pipelines where operators like limit and sort may need to reset their state. Limit needs it because it needs to know it's seeing a fresh set of input. Blocking operators like sort and distinct need it because they may not have drained their previous input due to a limit and thus need to be told to drop their old input and start over.

Overrides:

reset in class PhysicalOperator

clone

public POLimit clone()
              throws CloneNotSupportedException

Description copied from class: PhysicalOperator

Make a deep copy of this operator. This function is blank, however, we should leave a place holder so that the subclasses can clone

Overrides:

clone in class PhysicalOperator

Throws:

CloneNotSupportedException

See Also:

Do not use the clone method directly. Operators are cloned when logical plans are cloned using {@link LogicalPlanCloner}

illustratorMarkup

public Tuple illustratorMarkup(Object in,
                               Object out,
                               int eqClassIndex)

Description copied from interface: Illustrable

input tuple mark up to be illustrate-able

Parameters:

in - input tuple

out - output tuple before wrapped in ExampleTuple

eqClassIndex - index into equivalence classes in illustrator

Returns:

tuple