org.apache.calcite.rel.convert

Class ConverterRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.convert.ConverterRule

Direct Known Subclasses:

EnumerableBindable.EnumerableToBindableConverterRule, EnumerableCorrelateRule, EnumerableInterpreterRule, EnumerableTableFunctionScanRule, EnumerableTableModifyRule, EnumerableTableScanRule, EnumerableValuesRule, JdbcRules.JdbcTableModificationRule, JdbcRules.JdbcValuesRule, JdbcToEnumerableConverterRule, NoneToBindableConverterRule

public abstract class ConverterRule
extends RelOptRule

Abstract base class for a rule which converts from one calling convention to another without changing semantics.

Field Summary

Fields inherited from class org.apache.calcite.plan.RelOptRule

description, operands

Constructor Summary

Constructors

Constructor and Description
ConverterRule(Class<? extends RelNode> clazz, RelTrait in, RelTrait out, String description) Creates a ConverterRule.
ConverterRule(Class<R> clazz, com.google.common.base.Predicate<? super R> predicate, RelTrait in, RelTrait out, String description) Creates a ConverterRule with a predicate.

Method Summary

Methods

Modifier and Type	Method and Description
abstract RelNode	convert(RelNode rel)
RelTrait	getInTrait()
Convention	getOutConvention() Returns the convention of the result of firing this rule, null if not known.
RelTrait	getOutTrait() Returns the trait which will be modified as a result of firing this rule, or null if the rule is not a converter rule.
RelTraitDef	getTraitDef()
boolean	isGuaranteed() Returns true if this rule can convert any relational expression of the input convention.
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.

Methods inherited from class org.apache.calcite.plan.RelOptRule

any, convert, convert, convertList, equals, equals, getOperand, getOperands, hashCode, matches, none, operand, operand, operand, operand, operand, some, toString, unordered

Methods inherited from class java.lang.Object

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

Constructor Detail

ConverterRule

public ConverterRule(Class<? extends RelNode> clazz,
             RelTrait in,
             RelTrait out,
             String description)

Creates a ConverterRule.

Parameters:

clazz - Type of relational expression to consider converting

in - Trait of relational expression to consider converting

out - Trait which is converted to

description - Description of rule

ConverterRule

public ConverterRule(Class<R> clazz,
             com.google.common.base.Predicate<? super R> predicate,
             RelTrait in,
             RelTrait out,
             String description)

Creates a ConverterRule with a predicate.

Parameters:

clazz - Type of relational expression to consider converting

predicate - Predicate on the relational expression

in - Trait of relational expression to consider converting

out - Trait which is converted to

description - Description of rule

Method Detail

getOutConvention

public Convention getOutConvention()

Description copied from class: RelOptRule

Returns the convention of the result of firing this rule, null if not known.

Overrides:

getOutConvention in class RelOptRule

Returns:

Convention of the result of firing this rule, null if not known

getOutTrait

public RelTrait getOutTrait()

Description copied from class: RelOptRule

Returns the trait which will be modified as a result of firing this rule, or null if the rule is not a converter rule.

Overrides:

getOutTrait in class RelOptRule

Returns:

Trait which will be modified as a result of firing this rule, or null if the rule is not a converter rule

getInTrait

public RelTrait getInTrait()

getTraitDef

public RelTraitDef getTraitDef()

convert

public abstract RelNode convert(RelNode rel)

isGuaranteed

public boolean isGuaranteed()

Returns true if this rule can convert any relational expression of the input convention.

The union-to-java converter, for example, is not guaranteed, because it only works on unions.

Returns:

true if this rule can convert any relational expression

onMatch

public void onMatch(RelOptRuleCall call)

Description copied from class: RelOptRule

Receives notification about a rule match. At the time that this method is called, call.rels holds the set of relational expressions which match the operands to the rule; call.rels[0] is the root expression.

Typically a rule would check that the nodes are valid matches, creates a new expression, then calls back RelOptRuleCall.transformTo(org.apache.calcite.rel.RelNode, java.util.Map<org.apache.calcite.rel.RelNode, org.apache.calcite.rel.RelNode>) to register the expression.

Specified by:

onMatch in class RelOptRule

Parameters:

call - Rule call

See Also:

RelOptRule.matches(RelOptRuleCall)