Package org.apache.calcite.rel.core

Class Window

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.SingleRel

org.apache.calcite.rel.core.Window

All Implemented Interfaces:

java.lang.Cloneable, RelOptNode, RelNode

Direct Known Subclasses:

Bindables.BindableWindow, EnumerableWindow, LogicalWindow

public abstract class Window
extends SingleRel

A relational expression representing a set of window aggregates.

A Window can handle several window aggregate functions, over several partitions, with pre- and post-expressions, and an optional post-filter. Each of the partitions is defined by a partition key (zero or more columns) and a range (logical or physical). The partitions expect the data to be sorted correctly on input to the relational expression.

Each Window.Group has a set of RexOver objects.

Created by ProjectToWindowRule.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Window.Group	Group of windowed aggregate calls that have the same window specification.
static class	Window.RexWinAggCall	A call to a windowed aggregate function.

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

RelNode.Context

Field Summary

Fields

Modifier and Type	Field	Description
com.google.common.collect.ImmutableList<RexLiteral>	constants
com.google.common.collect.ImmutableList<Window.Group>	groups

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

Constructor	Description
Window(RelOptCluster cluster, RelTraitSet traitSet, RelNode input, java.util.List<RexLiteral> constants, RelDataType rowType, java.util.List<Window.Group> groups)	Creates a window relational expression.

Method Summary

Modifier and Type	Method	Description
RelOptCost	computeSelfCost(RelOptPlanner planner, RelMetadataQuery mq)	Returns the cost of this plan (not including children).
RelWriter	explainTerms(RelWriter pw)	Describes the inputs and attributes of this relational expression.
static RelCollation	getCollation(java.util.List<RexFieldCollation> collations)
java.util.List<RexLiteral>	getConstants()	Returns constants that are additional inputs of current relation.
static ImmutableIntList	getProjectOrdinals(java.util.List<RexNode> exprs)
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, accept, collectVariablesSet, collectVariablesUsed, computeDigest, computeSelfCost, copy, explain, getChildExps, 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

groups

public final com.google.common.collect.ImmutableList<Window.Group> groups

constants

public final com.google.common.collect.ImmutableList<RexLiteral> constants

Constructor Detail

Window

public Window(RelOptCluster cluster,
              RelTraitSet traitSet,
              RelNode input,
              java.util.List<RexLiteral> constants,
              RelDataType rowType,
              java.util.List<Window.Group> groups)

Creates a window relational expression.

Parameters:

cluster - Cluster

traitSet - Trait set

input - Input relational expression

constants - List of constants that are additional inputs

rowType - Output row type

groups - Windows

Method Detail

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

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

getProjectOrdinals

public static ImmutableIntList getProjectOrdinals(java.util.List<RexNode> exprs)

getCollation

public static RelCollation getCollation(java.util.List<RexFieldCollation> collations)

getConstants

public java.util.List<RexLiteral> getConstants()

Returns constants that are additional inputs of current relation.

Returns:

constants that are additional inputs of current relation

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)