org.apache.flink.table.operations.utils

Class OperationExpressionsUtils

java.lang.Object

org.apache.flink.table.operations.utils.OperationExpressionsUtils

@Internal
public class OperationExpressionsUtils
extends Object

Utility methods for transforming Expression to use them in QueryOperations.

Note: Some of these utilities are intended to be used before expressions are fully resolved and some afterwards.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	OperationExpressionsUtils.CategorizedExpressions Container for extracted expressions of the same family.

Method Summary

Modifier and Type	Method and Description
static OperationExpressionsUtils.CategorizedExpressions	extractAggregationsAndProperties(List<Expression> expressions) Extracts and deduplicates all aggregation and window property expressions (zero, one, or more) from the given expressions.
static Optional<String>	extractName(Expression expression) Extracts name from given expression if it has one.
static List<Optional<String>>	extractNames(List<ResolvedExpression> expressions) Extracts names from given expressions if they have one.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

extractAggregationsAndProperties

public static OperationExpressionsUtils.CategorizedExpressions extractAggregationsAndProperties(List<Expression> expressions)

Extracts and deduplicates all aggregation and window property expressions (zero, one, or more) from the given expressions.

Parameters:

expressions - a list of expressions to extract

Returns:

a Tuple2, the first field contains the extracted and deduplicated aggregations, and the second field contains the extracted and deduplicated window properties.

extractNames

public static List<Optional<String>> extractNames(List<ResolvedExpression> expressions)

Extracts names from given expressions if they have one. Expressions that have names are:

• FieldReferenceExpression
• TableReferenceExpression
• LocalReferenceExpression
• BuiltInFunctionDefinitions.AS

Parameters:

expressions - list of expressions to extract names from

Returns:

corresponding list of optional names

extractName

public static Optional<String> extractName(Expression expression)

Extracts name from given expression if it has one. Expressions that have names are:

• FieldReferenceExpression
• TableReferenceExpression
• LocalReferenceExpression
• BuiltInFunctionDefinitions.AS

Parameters:

expression - expression to extract name from

Returns:

optional name of given expression