net.sf.saffron.rel
Class ProjectRelBase

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

Direct Known Subclasses:

IterCalcRel, ProjectRel

public abstract class ProjectRelBase

extends SingleRel

ProjectRelBase is an abstract base class for SaffronRels which perform projection. SaffronRels which combine projection with other operations should subclass ProjectRelBase rather than ProjectRel (which represents pure projection).

Nested Class Summary

static interface

ProjectRelBase.Flags

Field Summary

protected RexNode[]	exps
protected String[]	fieldNames
protected int	flags Values defined in ProjectRelBase.Flags.

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

child

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

cluster, digest, emptyArray, id, nextId, rowType

Constructor Summary

protected

ProjectRelBase(VolcanoCluster cluster, SaffronRel child, RexNode[] exps, String[] fieldNames, int flags) Creates a Project.

Method Summary

PlanCost	computeSelfCost(SaffronPlanner planner) Returns the cost of this plan (not including children).
protected void	defineTerms(String[] terms)
protected SaffronType	deriveRowType()
void	explain(PlanWriter pw)
RexNode[]	getChildExps() Returns an array of this SaffronRel's child expressions (not including the inputs returned by SingleRel.getInputs().
String[]	getFieldNames()
int	getFlags()
SaffronRel	implementFieldAccess(RelImplementor implementor, String fieldName) Burrows into a synthetic record and returns the underlying relation which provides the field called fieldName.
boolean	isBoxed()

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

childrenAccept, getInputs, getRows, replaceInput

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

clone, computeDigest, getCluster, getConvention, getCorrelVariable, getId, getInput, getOrCreateCorrelVariable, getQualifier, getQuery, getRelTypeName, getRowType, getTable, getVariablesStopped, implement, 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

exps

protected RexNode[] exps

fieldNames

protected String[] fieldNames

flags

protected int flags

Values defined in ProjectRelBase.Flags.

Constructor Detail

ProjectRelBase

protected ProjectRelBase(VolcanoCluster cluster,
                         SaffronRel child,
                         RexNode[] exps,
                         String[] fieldNames,
                         int flags)

Creates a Project.

Parameters:

cluster - VolcanoCluster this relational expression belongs to

child - input relational expression

exps - set of expressions for the input columns

fieldNames - aliases of the expressions

flags - values as in ProjectRelBase.Flags

Method Detail

isBoxed

public boolean isBoxed()

getChildExps

public RexNode[] getChildExps()

Description copied from class: SaffronRel

Returns an array of this SaffronRel's child expressions (not including the inputs returned by SaffronRel.getInputs(). If there are no child expressions, returns an empty array, not null.

Overrides:

getChildExps in class SaffronRel

getFieldNames

public String[] getFieldNames()

getFlags

public int getFlags()

computeSelfCost

public PlanCost computeSelfCost(SaffronPlanner planner)

Description copied from class: SaffronRel

Returns the cost of this plan (not including children). The base implementation throws an error; derived classes should override.

Overrides:

computeSelfCost in class SaffronRel

defineTerms

protected void defineTerms(String[] terms)

explain

public void explain(PlanWriter pw)

Overrides:

explain in class SingleRel

implementFieldAccess

public SaffronRel implementFieldAccess(RelImplementor implementor,
                                       String fieldName)

Description copied from class: SaffronRel

Burrows into a synthetic record and returns the underlying relation which provides the field called fieldName.

Overrides:

implementFieldAccess in class SaffronRel

deriveRowType

protected SaffronType deriveRowType()

Overrides:

deriveRowType in class SingleRel