Package org.apache.calcite.rel

Class SingleRel

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.SingleRel

All Implemented Interfaces:

Cloneable, RelOptNode, RelNode

Direct Known Subclasses:

Aggregate, Calc, CassandraLimit, Chi, Collect, ConverterImpl, Delta, EnumerableInterpreter, EnumerableLimit, Exchange, Filter, JdbcRules.JdbcCalc, Match, Project, Sample, Snapshot, Sort, SparkRules.SparkCalc, Spool, TableModify, Uncollect, Window

public abstract class SingleRel
extends AbstractRelNode

Abstract base class for relational expressions with a single input.

It is not required that single-input relational expressions use this class as a base class. However, default implementations of methods make life easier.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.calcite.rel.RelNode

RelNode.Context

Field Summary

Fields

Modifier and Type	Field	Description
protected RelNode	input

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

digest, id, rowType, traitSet

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SingleRel(RelOptCluster cluster, RelTraitSet traits, RelNode input)	Creates a SingleRel.

Method Summary

Modifier and Type	Method	Description
void	childrenAccept(RelVisitor visitor)	Interacts with the RelVisitor in a visitor pattern to traverse the tree of relational expressions.
protected RelDataType	deriveRowType()
double	estimateRowCount(RelMetadataQuery mq)	Returns an estimate of the number of rows this relational expression will return.
RelWriter	explainTerms(RelWriter pw)	Describes the inputs and attributes of this relational expression.
RelNode	getInput()
List<RelNode>	getInputs()	Returns an array of this relational expression's inputs.
void	replaceInput(int ordinalInParent, RelNode rel)	Replaces the ordinalInParentth input.

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

accept, accept, collectVariablesSet, collectVariablesUsed, computeSelfCost, copy, deepEquals, deepHashCode, equals, explain, getCluster, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getRelDigest, getRelTypeName, getRowType, getTable, getTraitSet, getVariablesSet, hashCode, isEnforcer, isValid, metadata, onRegister, recomputeDigest, register, sole, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.calcite.rel.RelNode

explain, fieldIsNullable, stripped

Field Details

input

protected RelNode input

Constructor Details

SingleRel

protected SingleRel(RelOptCluster cluster,
 RelTraitSet traits,
 RelNode input)

Creates a SingleRel.

Parameters:

cluster - Cluster this relational expression belongs to

input - Input relational expression

Method Details

getInput

public RelNode getInput()

getInputs

public List<RelNode> getInputs()

Description copied from interface: RelNode

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

Specified by:

getInputs in interface RelNode

Specified by:

getInputs in interface RelOptNode

Overrides:

getInputs in class AbstractRelNode

Returns:

Array of this relational expression's inputs

estimateRowCount

public double estimateRowCount(RelMetadataQuery mq)

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:

estimateRowCount in interface RelNode

Overrides:

estimateRowCount in class AbstractRelNode

Parameters:

mq - Metadata query

Returns:

Estimate of the number of rows this relational expression will return

childrenAccept

public void childrenAccept(RelVisitor visitor)

Description copied from interface: RelNode

Interacts with the RelVisitor in a visitor pattern to traverse the tree of relational expressions.

Specified by:

childrenAccept in interface RelNode

Overrides:

childrenAccept in class AbstractRelNode

Parameters:

visitor - Visitor that will traverse the tree of relational expressions

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 RelWriter.input(String, RelNode) and RelWriter.item(String, Object) methods for each input and attribute.

Overrides:

explainTerms in class AbstractRelNode

Parameters:

pw - Plan writer

Returns:

Plan writer for fluent-explain pattern

replaceInput

public void replaceInput(int ordinalInParent,
 RelNode rel)

Description copied from interface: RelNode

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

Specified by:

replaceInput in interface RelNode

Overrides:

replaceInput in class AbstractRelNode

Parameters:

ordinalInParent - Position of the child input, 0 is the first

rel - New node that should be put at position ordinalInParent

deriveRowType

protected RelDataType deriveRowType()

Overrides:

deriveRowType in class AbstractRelNode