org.apache.flink.table.expressions

Interface Expression

All Known Subinterfaces:

ResolvedExpression

All Known Implementing Classes:

AggregateExpression, ApiExpression, CallExpression, FieldReferenceExpression, LocalReferenceExpression, LookupCallExpression, RexNodeExpression, SqlCallExpression, TableReferenceExpression, TypeLiteralExpression, UnresolvedCallExpression, UnresolvedReferenceExpression, ValueLiteralExpression

@PublicEvolving
public interface Expression

General interface for all kinds of expressions.

Expressions represent a logical tree for producing a computation result. Every expression consists of zero, one, or more subexpressions. Expressions might be literal values, function calls, or field references.

Expressions are part of the API. They might be transformed multiple times within the API stack until they are fully ResolvedExpressions. Value types and output types are expressed as instances of DataType.

Method Summary

Modifier and Type	Method and Description
<R> R	accept(ExpressionVisitor<R> visitor)
String	asSummaryString() Returns a string that summarizes this expression for printing to a console.
List<Expression>	getChildren()

Method Detail

asSummaryString

String asSummaryString()

Returns a string that summarizes this expression for printing to a console. An implementation might skip very specific properties.

Returns:

summary string of this expression for debugging purposes

getChildren

List<Expression> getChildren()

accept

<R> R accept(ExpressionVisitor<R> visitor)