org.apache.pig.experimental.logical.relational
Class LogicalRelationalOperator

java.lang.Object
  org.apache.pig.experimental.plan.Operator
      org.apache.pig.experimental.logical.relational.LogicalRelationalOperator

Direct Known Subclasses:

LOCogroup, LOFilter, LOForEach, LOGenerate, LOInnerLoad, LOJoin, LOLoad, LOSplit, LOSplitOutput, LOStore, LOUnion

public abstract class LogicalRelationalOperator
extends Operator

Logical representation of relational operators. Relational operators have a schema.

Field Summary

protected String	alias
protected int	lineNum
protected int	requestedParallelism
protected LogicalSchema	schema

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

annotations, hashPrime, name, plan

Constructor Summary

LogicalRelationalOperator(String name, OperatorPlan plan)

LogicalRelationalOperator(String name, OperatorPlan plan, int rp)

Method Summary

protected boolean	checkEquality(LogicalRelationalOperator other) Do some basic equality checks on two relational operators.
String	getAlias() Get the alias of this operator.
int	getLineNumber() Get the line number in the submitted Pig Latin script where this operator occurred.
int	getRequestedParallelisam() Get the requestedParallelism for this operator.
abstract LogicalSchema	getSchema() Get the schema for the output of this relational operator.
void	neverUseForRealSetSchema(LogicalSchema schema) Only to be used by unit tests.
void	resetSchema() Reset the schema to null so that the next time getSchema is called the schema will be regenerated from scratch.
void	setAlias(String alias)
void	setRequestedParallelism(int parallel)
String	toString()

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

accept, annotate, getAnnotation, getName, getPlan, isEqual, removeAnnotation

Methods inherited from class java.lang.Object

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

Field Detail

schema

protected LogicalSchema schema

requestedParallelism

protected int requestedParallelism

alias

protected String alias

lineNum

protected int lineNum

Constructor Detail

LogicalRelationalOperator

public LogicalRelationalOperator(String name,
                                 OperatorPlan plan)

Parameters:

name - of this operator

plan - this operator is in

LogicalRelationalOperator

public LogicalRelationalOperator(String name,
                                 OperatorPlan plan,
                                 int rp)

Parameters:

name - of this operator

plan - this operator is in

rp - requested parallelism

Method Detail

getSchema

public abstract LogicalSchema getSchema()

Get the schema for the output of this relational operator. This does not merely return the schema variable. If schema is not yet set, this will attempt to construct it. Therefore it is abstract since each operator will need to construct its schema differently.

Returns:

the schema

resetSchema

public void resetSchema()

Reset the schema to null so that the next time getSchema is called the schema will be regenerated from scratch.

getRequestedParallelisam

public int getRequestedParallelisam()

Get the requestedParallelism for this operator.

Returns:

requestedParallelsim

getAlias

public String getAlias()

Get the alias of this operator. That is, if the Pig Latin for this operator was 'X = sort W by $0' then the alias will be X. For store and split it will be the alias being stored or split. Note that because of this this alias is not guaranteed to be unique to a single operator.

Returns:

alias

setAlias

public void setAlias(String alias)

setRequestedParallelism

public void setRequestedParallelism(int parallel)

getLineNumber

public int getLineNumber()

Get the line number in the submitted Pig Latin script where this operator occurred.

Returns:

line number

neverUseForRealSetSchema

public void neverUseForRealSetSchema(LogicalSchema schema)

Only to be used by unit tests. This is a back door cheat to set the schema without having to calculate it. This should never be called by production code, only by tests.

Parameters:

schema - to set

checkEquality

protected boolean checkEquality(LogicalRelationalOperator other)

Do some basic equality checks on two relational operators. Equality is defined here as having equal schemas and predecessors that are equal. This is intended to be used by operators' equals methods.

Parameters:

other - LogicalRelationalOperator to compare predecessors against

Returns:

true if the isEquals() methods of this node's predecessor(s) returns true when invoked with other's predecessor(s).

toString

public String toString()

Overrides:

toString in class Object