org.eigenbase.rel
Class FilterRelBase

java.lang.Object
  org.eigenbase.rel.AbstractRelNode
      org.eigenbase.rel.SingleRel
          org.eigenbase.rel.FilterRelBase

All Implemented Interfaces:

Cloneable, RelNode

Direct Known Subclasses:

FilterRel

public abstract class FilterRelBase
extends SingleRel

FilterRelBase is an abstract base class for implementations of FilterRel.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/FilterRelBase.java#10 $

Author:

John V. Sichi

Field Summary

private RexNode

condition

Fields inherited from class org.eigenbase.rel.AbstractRelNode

digest, id, nextId, rowType, traits

Fields inherited from interface org.eigenbase.rel.RelNode

emptyArray

Constructor Summary

protected

FilterRelBase(RelOptCluster cluster, RelTraitSet traits, RelNode child, RexNode condition) Creates a filter.

Method Summary

RelOptCost	computeSelfCost(RelOptPlanner planner) Returns the cost of this plan (not including children).
static double	estimateFilteredRows(RelNode child, RexNode condition)
static double	estimateFilteredRows(RelNode child, RexProgram program)
void	explain(RelOptPlanWriter pw)
RexNode[]	getChildExps() Returns an array of this relational expression's child expressions (not including the inputs returned by RelNode.getInputs().
RexNode	getCondition()
double	getRows() Returns an estimate of the number of rows this relational expression will return.

Methods inherited from class org.eigenbase.rel.SingleRel

childrenAccept, deriveRowType, getChild, getInputs, replaceInput

Methods inherited from class org.eigenbase.rel.AbstractRelNode

clone, cloneTraits, collectVariablesSet, collectVariablesUsed, computeDigest, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getOrCreateCorrelVariable, getQuery, getRelTypeName, getRowType, getTable, getTraits, getVariablesStopped, inheritTraitsFrom, isAccessTo, isDistinct, isValid, 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

private final RexNode condition

Constructor Detail

FilterRelBase

protected FilterRelBase(RelOptCluster cluster,
                        RelTraitSet traits,
                        RelNode child,
                        RexNode condition)

Creates a filter.

Parameters:

cluster - RelOptCluster this relational expression belongs to

traits - the traits of this rel

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 interface: RelNode

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

Specified by:

getChildExps in interface RelNode

Overrides:

getChildExps in class AbstractRelNode

getCondition

public RexNode getCondition()

computeSelfCost

public RelOptCost computeSelfCost(RelOptPlanner planner)

Description copied from interface: RelNode

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

NOTE jvs 29-Mar-2006: Don't call this method directly. Instead, use RelMetadataQuery.getNonCumulativeCost(org.eigenbase.rel.RelNode), which gives plugins a chance to override the rel's default ideas about cost.

Specified by:

computeSelfCost in interface RelNode

Overrides:

computeSelfCost in class AbstractRelNode

getRows

public double getRows()

Description copied from interface: RelNode

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

NOTE jvs 29-Mar-2006: Don't call this method directly. Instead, use RelMetadataQuery.getRowCount(org.eigenbase.rel.RelNode), which gives plugins a chance to override the rel's default ideas about row count.

Specified by:

getRows in interface RelNode

Overrides:

getRows in class SingleRel

estimateFilteredRows

public static double estimateFilteredRows(RelNode child,
                                          RexProgram program)

estimateFilteredRows

public static double estimateFilteredRows(RelNode child,
                                          RexNode condition)

explain

public void explain(RelOptPlanWriter pw)

Specified by:

explain in interface RelNode

Overrides:

explain in class SingleRel