cascading.pipe.joiner

Class MixedJoin

java.lang.Object

cascading.pipe.joiner.BaseJoiner

cascading.pipe.joiner.MixedJoin

All Implemented Interfaces:

DeclaresResults, Joiner, Serializable

public class MixedJoin
extends BaseJoiner

Class MixedJoin will return an Iterator that will iterate over a given Joiner and return tuples that represent a join as defined by the given boolean array.

So if joining three streams, boolean []{true,false,false} will result in a 'inner', 'outer', 'outer' join.

Joins perform based on the equality of the join keys. In the case of null values, Java treats two null values as equivalent. SQL does not treat null values as equal. To produce SQL like results in a given join, a new Comparator will need to be used on the joined values to prevent null from equaling null. As a convenience, see the NullNotEquivalentComparator class.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	MixedJoin.JoinIterator

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	INNER Field INNER
static boolean	OUTER Field OUTER

Constructor Summary

Constructors

Constructor and Description
MixedJoin(boolean[] asInner) Constructor MixedJoin creates a new MixedJoin instance.
MixedJoin(Fields fieldDeclaration, boolean[] asInner)

Method Summary

Methods

Modifier and Type	Method and Description
Iterator<Tuple>	getIterator(JoinerClosure closure) Returns an iterator that joins the given CoGroupClosure co-groups.
int	numJoins() Returns the number of joins this instance can handle.

Methods inherited from class cascading.pipe.joiner.BaseJoiner

getFieldDeclaration

Methods inherited from class java.lang.Object

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

Field Detail

INNER

public static boolean INNER

Field INNER

OUTER

public static boolean OUTER

Field OUTER

Constructor Detail

MixedJoin

@ConstructorProperties(value="asInner")
public MixedJoin(boolean[] asInner)

Constructor MixedJoin creates a new MixedJoin instance.

Parameters:

asInner - of type boolean[]

MixedJoin

@ConstructorProperties(value={"fieldDeclaration","asInner"})
public MixedJoin(Fields fieldDeclaration,
                                    boolean[] asInner)

Method Detail

numJoins

public int numJoins()

Description copied from interface: Joiner

Returns the number of joins this instance can handle. A value of -1 denotes there is no limit.

Returns:

an int

See Also:

Joiner.numJoins()

getIterator

public Iterator<Tuple> getIterator(JoinerClosure closure)

Description copied from interface: Joiner

Returns an iterator that joins the given CoGroupClosure co-groups.

Parameters:

closure - of type GroupClosure

Returns:

an iterator