Package org.apache.calcite.rel.core

Class Project

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.SingleRel

org.apache.calcite.rel.core.Project

All Implemented Interfaces:

java.lang.Cloneable, RelOptNode, RelNode

Direct Known Subclasses:

Bindables.BindableProject, CassandraProject, ElasticsearchProject, EnumerableProject, GeodeProject, JdbcRules.JdbcProject, LogicalProject, MongoProject, PigProject

public abstract class Project
extends SingleRel

Relational expression that computes a set of 'select expressions' from its input relational expression.

See Also:

LogicalProject

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Project.Flags	Deprecated.

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

RelNode.Context

Field Summary

Fields

Modifier and Type	Field	Description
protected com.google.common.collect.ImmutableList<RexNode>	exps

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

input

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

digest, id, rowType, traitSet

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Project(RelOptCluster cluster, RelTraitSet traits, RelNode input, java.util.List<? extends RexNode> projects, RelDataType rowType)	Creates a Project.
protected	Project(RelOptCluster cluster, RelTraitSet traitSet, RelNode input, java.util.List<? extends RexNode> projects, RelDataType rowType, int flags)	Deprecated.
protected	Project(RelInput input)	Creates a Project by parsing serialized output.

Method Summary

Modifier and Type	Method	Description
RelNode	accept(RexShuttle shuttle)	Accepts a visit from a shuttle.
RelOptCost	computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq)	Returns the cost of this plan (not including children).
RelNode	copy(RelTraitSet traitSet, java.util.List<RelNode> inputs)	Creates a copy of this relational expression, perhaps changing traits and inputs.
abstract Project	copy(RelTraitSet traitSet, RelNode input, java.util.List<RexNode> projects, RelDataType rowType)	Copies a project.
Project	copy(RelTraitSet traitSet, RelNode input, java.util.List<RexNode> projects, RelDataType rowType, int flags)	Deprecated.
RelWriter	explainTerms(RelWriter pw)	Describes the inputs and attributes of this relational expression.
java.util.List<RexNode>	getChildExps()	Returns a list of this relational expression's child expressions.
int	getFlags()	Deprecated.
Mappings.TargetMapping	getMapping()	Returns a mapping, or null if this projection is not a mapping.
static Mappings.TargetMapping	getMapping(int inputFieldCount, java.util.List<? extends RexNode> projects)	Returns a mapping of a set of project expressions.
java.util.List<Pair<RexNode,java.lang.String>>	getNamedProjects()	Returns a list of (expression, name) pairs.
static Mappings.TargetMapping	getPartialMapping(int inputFieldCount, java.util.List<? extends RexNode> projects)	Returns a partial mapping of a set of project expressions.
Permutation	getPermutation()	Returns a permutation, if this projection is merely a permutation of its input fields; otherwise null.
static Permutation	getPermutation(int inputFieldCount, java.util.List<? extends RexNode> projects)	Returns a permutation, if this projection is merely a permutation of its input fields; otherwise null.
java.util.List<RexNode>	getProjects()	Returns the project expressions.
boolean	isBoxed()	Deprecated.
boolean	isMapping()	Checks whether this is a functional mapping.
boolean	isValid(Litmus litmus, RelNode.Context context)	Returns whether this relational expression is valid.

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

childrenAccept, deriveRowType, estimateRowCount, getInput, getInputs, replaceInput

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

accept, collectVariablesSet, collectVariablesUsed, computeDigest, computeSelfCost, explain, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getQuery, getRelTypeName, getRows, getRowType, getTable, getTraitSet, getVariablesSet, getVariablesStopped, isDistinct, isKey, isValid, 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

exps

protected final com.google.common.collect.ImmutableList<RexNode> exps

Constructor Detail

Project

protected Project(RelOptCluster cluster,
                  RelTraitSet traits,
                  RelNode input,
                  java.util.List<? extends RexNode> projects,
                  RelDataType rowType)

Creates a Project.

Parameters:

cluster - Cluster that this relational expression belongs to

traits - Traits of this relational expression

input - Input relational expression

projects - List of expressions for the input columns

rowType - Output row type

Project

@Deprecated
protected Project(RelOptCluster cluster,
                  RelTraitSet traitSet,
                  RelNode input,
                  java.util.List<? extends RexNode> projects,
                  RelDataType rowType,
                  int flags)

Deprecated.

Project

protected Project(RelInput input)

Creates a Project by parsing serialized output.

Method Detail

copy

public final RelNode copy(RelTraitSet traitSet,
                          java.util.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 Project copy(RelTraitSet traitSet,
                             RelNode input,
                             java.util.List<RexNode> projects,
                             RelDataType rowType)

Copies a project.

Parameters:

traitSet - Traits

input - Input

projects - Project expressions

rowType - Output row type

Returns:

New Project if any parameter differs from the value of this Project, or just this if all the parameters are the same

See Also:

copy(RelTraitSet, List)

copy

@Deprecated
public Project copy(RelTraitSet traitSet,
                    RelNode input,
                    java.util.List<RexNode> projects,
                    RelDataType rowType,
                    int flags)

Deprecated.

isBoxed

@Deprecated
public boolean isBoxed()

Deprecated.

getChildExps

public java.util.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

getProjects

public java.util.List<RexNode> getProjects()

Returns the project expressions.

Returns:

Project expressions

getNamedProjects

public final java.util.List<Pair<RexNode,java.lang.String>> getNamedProjects()

Returns a list of (expression, name) pairs. Convenient for various transformations.

Returns:

List of (expression, name) pairs

getFlags

@Deprecated
public int getFlags()

Deprecated.

isValid

public boolean isValid(Litmus litmus,
                       RelNode.Context context)

Description copied from interface: RelNode

Returns whether this relational expression is valid.

If assertions are enabled, this method is typically called with litmus = THROW, as follows:

assert rel.isValid(Litmus.THROW)

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:

litmus - What to do if invalid

context - Context for validity checking

Returns:

Whether relational expression is valid

computeSelfCost

public RelOptCost computeSelfCost(RelOptPlanner planner,
                                  RelMetadataQuery mq)

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

mq - Metadata query

Returns:

Cost of this plan (not including children)

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

getMapping

public Mappings.TargetMapping getMapping()

Returns a mapping, or null if this projection is not a mapping.

Returns:

Mapping, or null if this projection is not a mapping

getMapping

public static Mappings.TargetMapping getMapping(int inputFieldCount,
                                                java.util.List<? extends RexNode> projects)

Returns a mapping of a set of project expressions.

The mapping is an inverse surjection. Every target has a source field, but a source field may appear as zero, one, or more target fields. Thus you can safely call Mappings.TargetMapping.getTarget(int).

Parameters:

inputFieldCount - Number of input fields

projects - Project expressions

Returns:

Mapping of a set of project expressions, or null if projection is not a mapping

getPartialMapping

public static Mappings.TargetMapping getPartialMapping(int inputFieldCount,
                                                       java.util.List<? extends RexNode> projects)

Returns a partial mapping of a set of project expressions.

The mapping is an inverse function. Every target has a source field, but a source might have 0, 1 or more targets. Project expressions that do not consist of a mapping are ignored.

Parameters:

inputFieldCount - Number of input fields

projects - Project expressions

Returns:

Mapping of a set of project expressions, never null

getPermutation

public Permutation getPermutation()

Returns a permutation, if this projection is merely a permutation of its input fields; otherwise null.

Returns:

Permutation, if this projection is merely a permutation of its input fields; otherwise null

getPermutation

public static Permutation getPermutation(int inputFieldCount,
                                         java.util.List<? extends RexNode> projects)

Returns a permutation, if this projection is merely a permutation of its input fields; otherwise null.

isMapping

public boolean isMapping()

Checks whether this is a functional mapping. Every output is a source field, but a source field may appear as zero, one, or more output fields.