Package org.apache.calcite.adapter.csv
Class CsvProjectTableScanRule
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- org.apache.calcite.plan.RelOptRule
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- org.apache.calcite.adapter.csv.CsvProjectTableScanRule
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public class CsvProjectTableScanRule extends RelOptRule
Planner rule that projects from aCsvTableScan
scan just the columns needed to satisfy a projection. If the projection's expressions are trivial, the projection is removed.
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Field Summary
Fields Modifier and Type Field Description static CsvProjectTableScanRule
INSTANCE
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Fields inherited from class org.apache.calcite.plan.RelOptRule
description, operands, relBuilderFactory
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Constructor Summary
Constructors Constructor Description CsvProjectTableScanRule(RelBuilderFactory relBuilderFactory)
Creates a CsvProjectTableScanRule.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description private int[]
getProjectFields(java.util.List<RexNode> exps)
void
onMatch(RelOptRuleCall call)
Receives notification about a rule match.-
Methods inherited from class org.apache.calcite.plan.RelOptRule
any, convert, convert, convertList, convertOperand, convertOperand, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, hashCode, matches, none, operand, operand, operand, operand, operand, operandJ, operandJ, some, toString, unordered
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Field Detail
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INSTANCE
public static final CsvProjectTableScanRule INSTANCE
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Constructor Detail
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CsvProjectTableScanRule
public CsvProjectTableScanRule(RelBuilderFactory relBuilderFactory)
Creates a CsvProjectTableScanRule.- Parameters:
relBuilderFactory
- Builder for relational expressions
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Method Detail
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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 classRelOptRule
- Parameters:
call
- Rule call- See Also:
RelOptRule.matches(RelOptRuleCall)
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getProjectFields
private int[] getProjectFields(java.util.List<RexNode> exps)
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