org.apache.calcite.rel.rules

Class ProjectRemoveRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.rules.ProjectRemoveRule

public class ProjectRemoveRule
extends RelOptRule

Planner rule that, given a Project node that merely returns its input, converts the node into its child.

For example, Project(ArrayReader(a), {$input0}) becomes ArrayReader(a).

See Also:

CalcRemoveRule, ProjectMergeRule

Field Summary

Fields

Modifier and Type	Field and Description
static ProjectRemoveRule	INSTANCE

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

description, operands

Method Summary

Methods

Modifier and Type	Method and Description
static boolean	isIdentity(List<? extends RexNode> exps, RelDataType childRowType)
static boolean	isTrivial(Project project)
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.
static RelNode	strip(Project project) Returns the child of a project if the project is trivial, otherwise the project itself.

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

any, convert, convert, convertList, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, 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

Field Detail

INSTANCE

public static final ProjectRemoveRule INSTANCE

Method Detail

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)

strip

public static RelNode strip(Project project)

Returns the child of a project if the project is trivial, otherwise the project itself.

isTrivial

public static boolean isTrivial(Project project)

isIdentity

public static boolean isIdentity(List<? extends RexNode> exps,
                 RelDataType childRowType)