be.SIRAPRISE.typeimplementations

Class RelationalOperator

java.lang.Object

be.SIRAPRISE.typeimplementations.RelationalOperator

All Implemented Interfaces:

OperatorGenerator

Direct Known Subclasses:

AGGREGATE, DIVIDEBYPER, EXTEND, GROUP, GTCLOSE, INTERSECT, INTERSECTUSING, JOIN, JOINUSING, LEFTJOIN, LEFTJOINUSING, MINUS, MINUSUSING, PACK, PROJECT, RENAME, RESTRICT, SEMIJOIN, SEMIJOINUSING, SEMIMINUS, SEMIMINUSUSING, SUMMARIZEBY, TCLOSE, TRANSFORM, UNGROUP, UNION, UNIONUSING, UNPACK, XMINUS, XMINUSUSING

public abstract class RelationalOperator
extends java.lang.Object
implements OperatorGenerator

A NonScalarOperator is, in principle, an operator that takes nonscalar values as at least one of its arguments, and is in one of the following classes :

1. Detailed behaviour of the operator (and validity of its invocations) depend not solely on the nonscalar types involved, but also on Heading information associated with the arguments. Examples : JOIN, UNION, MINUS.
2. Detailed behaviour of the operator also depends on additional "parametric" information (e.g. EXTEND expressions, TCLOSE closure specs, PROJECT attribute listst, ...) provided in the invocations. Examples : EXTEND, RENAME, PROJECT, RESTRICT, TCLOSE.

Example of an operator that takes a nonscalar value as an argument but is not in either one of these categories is LENGTH(<RELATION>)

Author:

Erwin Smout

Constructor Summary

Constructors

Constructor and Description
RelationalOperator()

Method Summary

Modifier and Type	Method and Description
java.lang.String	getInvocationName() Gets the operator invocation name.
int	getMaximumArgumentCount() Gets the maximum argument count for this operator.
int	getMinimumArgumentCount() Gets the minimum argument count for this operator.
java.lang.String	getName() Gets the operator name.
java.util.List<OperatorGeneratorArgumentType>	getOperatorGeneratorSignature() Gets the operator generator signature.
boolean	isMonoRelationOperator() Checks if the operator takes only one Relation as input.
java.lang.String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface be.SIRAPRISE.typeimplementations.OperatorGenerator

getOperatorImplementation

Constructor Detail

RelationalOperator

public RelationalOperator()

Method Detail

getInvocationName

public java.lang.String getInvocationName()

Gets the operator invocation name. This default implementation returns the value specified in the OperatorGeneratorCharacteristics annotation, or this class' getSimpleName() if no such annotation exists.

Specified by:

getInvocationName in interface OperatorGenerator

Returns:

the operator invocation name

getMaximumArgumentCount

public int getMaximumArgumentCount()

Gets the maximum argument count for this operator. This default implementation returns the value specified in the OperatorGeneratorCharacteristics annotation, or 255 if there is no such annotation. Note that stuff like rename lists are regarded as an argument as far as this count is concerned.

Returns:

the maximum argument count for this operator.

getMinimumArgumentCount

public int getMinimumArgumentCount()

Gets the minimum argument count for this operator. This default implementation returns the value specified in the OperatorGeneratorCharacteristics annotation, or 0 if there is no such annotation. Note that stuff like rename lists are regarded as an argument as far as this count is concerned

Returns:

the minimum argument count for this operator

getName

public java.lang.String getName()

Gets the operator name. This default implementation returns the value specified in the OperatorGeneratorCharacteristics annotation, or this class' getSimpleName() if no such annotation exists.

Returns:

the operator name

getOperatorGeneratorSignature

public java.util.List<OperatorGeneratorArgumentType> getOperatorGeneratorSignature()

Gets the operator generator signature. This default implementation returns the value specified in the OperatorGeneratorCharacteristics annotation, or an empty list if no such annotation exists.

Specified by:

getOperatorGeneratorSignature in interface OperatorGenerator

Returns:

the operator generator signature

isMonoRelationOperator

public boolean isMonoRelationOperator()

Checks if the operator takes only one Relation as input. This default implementation returns true if an MonoRelationOperator annotation is present for the class, false otherwise.

Returns:

true if the operator takes only one Relation as input

toString

public final java.lang.String toString()

Overrides:

toString in class java.lang.Object