Package org.apache.flink.cdc.runtime.operators.transform

Class ProjectionColumn

java.lang.Object

org.apache.flink.cdc.runtime.operators.transform.ProjectionColumn

All Implemented Interfaces:

Serializable

public class ProjectionColumn
extends Object
implements Serializable

The ProjectionColumn applies to describe the information of the transformation column. If it only has column info, it describes the data column. If it has column info and expression info, it describes the user-defined computed columns.

A projection column contains:

• column: column information parsed from projection.
• expression: a string for column expression split from the user-defined projection.
• scriptExpression: a string for column script expression compiled from the column expression.
• originalColumnNames: a list for recording the name of all columns used by the column expression.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
ProjectionColumn(Column column, String expression, String scriptExpression, List<String> originalColumnNames, Map<String,String> columnNameMap)

Method Summary

Modifier and Type	Method	Description
ProjectionColumn	copy()
Column	getColumn()
String	getColumnName()
Map<String,String>	getColumnNameMap()
String	getColumnNameMapAsString()
DataType	getDataType()
String	getExpression()
List<String>	getOriginalColumnNames()
String	getScriptExpression()
boolean	isValidTransformedProjectionColumn()
static ProjectionColumn	ofAliased(Column column, String newName, String mappedColumnName)	This projection is created with a simple $id$ AS $new_id$ expression.
static ProjectionColumn	ofCalculated(String columnName, DataType dataType, String expression, String scriptExpression, List<String> originalColumnNames, Map<String,String> columnNameMap)	This projection is created with a complex calculation expression.
static ProjectionColumn	ofForwarded(Column column, String mappedColumnName)	This projection is created with a plain column name.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ProjectionColumn

public ProjectionColumn(Column column,
                        String expression,
                        String scriptExpression,
                        List<String> originalColumnNames,
                        Map<String,String> columnNameMap)

Method Detail

copy

public ProjectionColumn copy()

getColumn

public Column getColumn()

getColumnName

public String getColumnName()

getDataType

public DataType getDataType()

getExpression

public String getExpression()

getScriptExpression

public String getScriptExpression()

getOriginalColumnNames

public List<String> getOriginalColumnNames()

getColumnNameMap

public Map<String,String> getColumnNameMap()

getColumnNameMapAsString

public String getColumnNameMapAsString()

isValidTransformedProjectionColumn

public boolean isValidTransformedProjectionColumn()

ofForwarded

public static ProjectionColumn ofForwarded(Column column,
                                           String mappedColumnName)

This projection is created with a plain column name.
Just like column id in id, name AS new_name, age + 1 AS new_age.
Comments and default expressions will be intact.

ofAliased

public static ProjectionColumn ofAliased(Column column,
                                         String newName,
                                         String mappedColumnName)

This projection is created with a simple $id$ AS $new_id$ expression.
Just like column new_name in id, name AS new_name, age + 1 AS new_age.
Comments and default expressions will be intact.

ofCalculated

public static ProjectionColumn ofCalculated(String columnName,
                                            DataType dataType,
                                            String expression,
                                            String scriptExpression,
                                            List<String> originalColumnNames,
                                            Map<String,String> columnNameMap)

This projection is created with a complex calculation expression.
Just like column new_age in id, name AS new_name, age + 1 AS new_age.
No comments nor default expressions will be kept.

toString

public String toString()

Overrides:

toString in class Object