net.sf.saffron.rel
Class SingleRel

java.lang.Object
  |
  +--net.sf.saffron.rel.SaffronRel
        |
        +--net.sf.saffron.rel.SingleRel

Direct Known Subclasses:

AggregateRel, ConverterRel, DistinctRel, FilterRel, ProjectRelBase, SingleTerminatorRel, SortRel, TableModificationRel, VolcanoPlannerTest.TestSingleRel

public abstract class SingleRel

extends SaffronRel

A SingleRel is a base class single-input relational expressions.

Since:

23 September, 2001

Version:

$Id: //open/saffron/src/net/sf/saffron/rel/SingleRel.java#5 $

Author:

jhyde

Field Summary

SaffronRel

child

Fields inherited from class net.sf.saffron.rel.SaffronRel

cluster, digest, emptyArray, id, nextId, rowType

Constructor Summary

protected

SingleRel(VolcanoCluster cluster, SaffronRel child) Creates a SingleRel.

Method Summary

void	childrenAccept(RelVisitor visitor)
protected SaffronType	deriveRowType()
void	explain(PlanWriter pw)
SaffronRel[]	getInputs() Returns an array of this SaffronRel's inputs.
double	getRows() Returns an estimate of the number of rows this relational expression will return.
void	replaceInput(int ordinalInParent, SaffronRel rel) Replaces the ordinalInParentth input.

Methods inherited from class net.sf.saffron.rel.SaffronRel

clone, computeDigest, computeSelfCost, getChildExps, getCluster, getConvention, getCorrelVariable, getId, getInput, getOrCreateCorrelVariable, getQualifier, getQuery, getRelTypeName, getRowType, getTable, getVariablesStopped, implement, implementFieldAccess, isAccessTo, isDistinct, onRegister, recomputeDigest, register, registerCorrelVariable, setCorrelVariable, toString

Methods inherited from class java.lang.Object

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

Field Detail

child

public SaffronRel child

Constructor Detail

SingleRel

protected SingleRel(VolcanoCluster cluster,
                    SaffronRel child)

Creates a SingleRel.

Parameters:

cluster - VolcanoCluster this relational expression belongs to

child - input relational expression

Method Detail

getInputs

public SaffronRel[] getInputs()

Description copied from class: SaffronRel

Returns an array of this SaffronRel's inputs. If there are no inputs, returns an empty array, not null.

Overrides:

getInputs in class SaffronRel

getRows

public double getRows()

Description copied from class: SaffronRel

Returns an estimate of the number of rows this relational expression will return.

Overrides:

getRows in class SaffronRel

childrenAccept

public void childrenAccept(RelVisitor visitor)

Overrides:

childrenAccept in class SaffronRel

explain

public void explain(PlanWriter pw)

Overrides:

explain in class SaffronRel

replaceInput

public void replaceInput(int ordinalInParent,
                         SaffronRel rel)

Description copied from class: SaffronRel

Replaces the ordinalInParent^th input. You must override this method if you override SaffronRel.getInputs().

Overrides:

replaceInput in class SaffronRel

deriveRowType

protected SaffronType deriveRowType()

Specified by:

deriveRowType in class SaffronRel