io.cdap.directives.column

Class Keep

java.lang.Object

io.cdap.directives.column.Keep

All Implemented Interfaces:

Directive, Executor<List<Row>,List<Row>>, Lineage, Serializable

@Categories(categories="column")
public class Keep
extends Object
implements Directive, Lineage

This class Keep implements a directive that opposite of Drop columns. Instead of dropping the columns specified, it keeps only those columns that are specified.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static String	NAME

Fields inherited from interface io.cdap.wrangler.api.Directive

TYPE

Constructor Summary

Constructors

Constructor and Description
Keep()

Method Summary

Modifier and Type	Method and Description
UsageDefinition	define()
void	destroy()
List<Row>	execute(List<Row> rows, ExecutorContext context)
void	initialize(Arguments args)
Mutation	lineage()

Methods inherited from class java.lang.Object

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

Field Detail

NAME

public static final String NAME

See Also:

Constant Field Values

Constructor Detail

Keep

public Keep()

Method Detail

define

public UsageDefinition define()

Specified by:

define in interface Directive

initialize

public void initialize(Arguments args)
                throws DirectiveParseException

Specified by:

initialize in interface Executor<List<Row>,List<Row>>

Throws:

DirectiveParseException

destroy

public void destroy()

Specified by:

destroy in interface Executor<List<Row>,List<Row>>

execute

public List<Row> execute(List<Row> rows,
                         ExecutorContext context)
                  throws DirectiveExecutionException

Specified by:

execute in interface Executor<List<Row>,List<Row>>

Throws:

DirectiveExecutionException

lineage

public Mutation lineage()

Specified by:

lineage in interface Lineage