org.apache.calcite.rel.core

Class Filter

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.SingleRel

org.apache.calcite.rel.core.Filter

All Implemented Interfaces:

Cloneable, RelOptNode, RelNode

Direct Known Subclasses:

Bindables.BindableFilter, EnumerableFilter, JdbcRules.JdbcFilter, LogicalFilter

public abstract class Filter
extends SingleRel

Relational expression that iterates over its input and returns elements for which condition evaluates to true.

If the condition allows nulls, then a null value is treated the same as false.

See Also:

LogicalFilter

Field Summary

Fields

Modifier and Type	Field and Description
protected RexNode	condition

Fields inherited from class org.apache.calcite.rel.AbstractRelNode

digest, id, rowType, traitSet

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Filter(RelInput input) Creates a Filter by parsing serialized output.
protected	Filter(RelOptCluster cluster, RelTraitSet traits, RelNode child, RexNode condition) Creates a filter.

Method Summary

Methods

Modifier and Type	Method and Description
RelNode	accept(RexShuttle shuttle) Accepts a visit from a shuttle.
RelOptCost	computeSelfCost(RelOptPlanner planner) Returns the cost of this plan (not including children).
RelNode	copy(RelTraitSet traitSet, List<RelNode> inputs) Creates a copy of this relational expression, perhaps changing traits and inputs.
abstract Filter	copy(RelTraitSet traitSet, RelNode input, RexNode condition)
static double	estimateFilteredRows(RelNode child, RexNode condition)
static double	estimateFilteredRows(RelNode child, RexProgram program)
RelWriter	explainTerms(RelWriter pw) Describes the inputs and attributes of this relational expression.
List<RexNode>	getChildExps() Returns a list of this relational expression's child expressions.
RexNode	getCondition()
double	getRows() Returns an estimate of the number of rows this relational expression will return.
boolean	isValid(boolean fail) Returns whether this relational expression is valid.

Methods inherited from class org.apache.calcite.rel.SingleRel

childrenAccept, deriveRowType, getInput, getInputs, replaceInput

Methods inherited from class org.apache.calcite.rel.AbstractRelNode

accept, collectVariablesSet, collectVariablesUsed, computeDigest, explain, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getQuery, getRelTypeName, getRowType, getTable, getTraitSet, getVariablesStopped, isDistinct, isKey, metadata, onRegister, recomputeDigest, register, sole, toString

Methods inherited from class java.lang.Object

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

Field Detail

condition

protected final RexNode condition

Constructor Detail

Filter

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

Creates a filter.

Parameters:

cluster - Cluster that 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

Filter

protected Filter(RelInput input)

Creates a Filter by parsing serialized output.

Method Detail

copy

public final RelNode copy(RelTraitSet traitSet,
           List<RelNode> inputs)

Description copied from interface: RelNode

Creates a copy of this relational expression, perhaps changing traits and inputs.

Sub-classes with other important attributes are encouraged to create variants of this method with more parameters.

Specified by:

copy in interface RelNode

Overrides:

copy in class AbstractRelNode

Parameters:

traitSet - Trait set

inputs - Inputs

Returns:

Copy of this relational expression, substituting traits and inputs

copy

public abstract Filter copy(RelTraitSet traitSet,
          RelNode input,
          RexNode condition)

getChildExps

public List<RexNode> getChildExps()

Description copied from interface: RelNode

Returns a list of this relational expression's child expressions. (These are scalar expressions, and so do not include the relational inputs that are returned by RelNode.getInputs().

The caller should treat the list as unmodifiable; typical implementations will return an immutable list. If there are no child expressions, returns an empty list, not null.

Specified by:

getChildExps in interface RelNode

Overrides:

getChildExps in class AbstractRelNode

Returns:

List of this relational expression's child expressions

See Also:

RelNode.accept(org.apache.calcite.rex.RexShuttle)

accept

public RelNode accept(RexShuttle shuttle)

Description copied from interface: RelNode

Accepts a visit from a shuttle. If the shuttle updates expression, then a copy of the relation should be created.

Specified by:

accept in interface RelNode

Overrides:

accept in class AbstractRelNode

Parameters:

shuttle - Shuttle

Returns:

A copy of this node incorporating changes made by the shuttle to this node's children

getCondition

public RexNode getCondition()

isValid

public boolean isValid(boolean fail)

Description copied from interface: RelNode

Returns whether this relational expression is valid.

If assertions are enabled, this method is typically called with fail = true, as follows:

assert rel.isValid(true)

This signals that the method can throw an AssertionError if it is not valid.

Specified by:

isValid in interface RelNode

Overrides:

isValid in class AbstractRelNode

Parameters:

fail - Whether to fail if invalid

Returns:

Whether relational expression is valid

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.apache.calcite.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

Parameters:

planner - Planner for cost calculation

Returns:

Cost of this plan (not including children)

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.apache.calcite.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

Returns:

Estimate of the number of rows this relational expression will return

estimateFilteredRows

public static double estimateFilteredRows(RelNode child,
                          RexProgram program)

estimateFilteredRows

public static double estimateFilteredRows(RelNode child,
                          RexNode condition)

explainTerms

public RelWriter explainTerms(RelWriter pw)

Description copied from class: AbstractRelNode

Describes the inputs and attributes of this relational expression. Each node should call super.explainTerms, then call the RelWriterImpl.input(String, RelNode) and RelWriterImpl.item(String, Object) methods for each input and attribute.

Overrides:

explainTerms in class SingleRel

Parameters:

pw - Plan writer

Returns:

Plan writer for fluent-explain pattern