org.apache.flink.table.planner.expressions

Class ColumnReferenceFinder

java.lang.Object

org.apache.flink.table.planner.expressions.ColumnReferenceFinder

public class ColumnReferenceFinder
extends Object

A finder used to look up referenced column name in a ResolvedExpression.

Method Summary

Modifier and Type	Method and Description
static Set<String>	findReferencedColumn(String columnName, ResolvedSchema schema) Find referenced column names that derive the computed column.
static Set<String>	findWatermarkReferencedColumn(ResolvedSchema schema) Find referenced column names that derive the watermark expression.

Methods inherited from class java.lang.Object

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

Method Detail

findReferencedColumn

public static Set<String> findReferencedColumn(String columnName,
                                               ResolvedSchema schema)

Find referenced column names that derive the computed column.

Parameters:

columnName - the name of the column

schema - the schema contains the computed column definition

Returns:

the referenced column names

findWatermarkReferencedColumn

public static Set<String> findWatermarkReferencedColumn(ResolvedSchema schema)

Find referenced column names that derive the watermark expression.

Parameters:

schema - resolved columns contains the watermark expression.

Returns:

the referenced column names