net.sf.saffron.rel
Class FilterRel

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

Direct Known Subclasses:

JavaFilterRel

public class FilterRel

extends SingleRel

A FilterRel is a relational expression which iterates over its input, and returns elements for which condition evaluates to true.

Field Summary

RexNode

condition

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

FilterRel(VolcanoCluster cluster, SaffronRel child, RexNode condition)
Creates a filter.

Method Summary

Object	clone()
PlanCost	computeSelfCost(SaffronPlanner planner) Returns the cost of this plan (not including children).
void	explain(PlanWriter pw)
RexNode[]	getChildExps() Returns an array of this SaffronRel's child expressions (not including the inputs returned by SingleRel.getInputs().
double	getRows() Returns an estimate of the number of rows this relational expression will return.

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

childrenAccept, deriveRowType, getInputs, replaceInput

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

computeDigest, 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

condition

public RexNode condition

Constructor Detail

FilterRel

public FilterRel(VolcanoCluster cluster,
                 SaffronRel child,
                 RexNode condition)

Creates a filter.

Parameters:

cluster - VolcanoCluster this relational expression belongs to

child - input relational expression

condition - boolean expression which determines whether a row is allowed to pass

Method Detail

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

clone

public Object clone()

Specified by:

clone in class SaffronRel

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

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 SingleRel

explain

public void explain(PlanWriter pw)

Overrides:

explain in class SingleRel