cascading.pipe.joiner
Class LeftJoin

java.lang.Object
  extended by cascading.pipe.joiner.LeftJoin
All Implemented Interfaces:
Joiner, Serializable

public class LeftJoin
extends Object
implements Joiner

Class LeftJoin will return an LeftJoin.JoinIterator that will iterate over a given Joiner and return tuples that represent a left inner, right outer join of the CoGrouper internal grouped tuple collections.

Note only the farthest right tuple stream will be used as the outer join. All preceding joins to the left will be inner joins. See MixedJoin for more flexibility.

See Also:
MixedJoin, Serialized Form

Nested Class Summary
static class LeftJoin.JoinIterator
           
 
Constructor Summary
LeftJoin()
           
 
Method Summary
 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 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

LeftJoin

public LeftJoin()
Method Detail

getIterator

public Iterator<Tuple> getIterator(JoinerClosure closure)
Description copied from interface: Joiner
Returns an iterator that joins the given CoGroupClosure co-groups.

Specified by:
getIterator in interface Joiner
Parameters:
closure - of type GroupClosure
Returns:
an iterator

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.

Specified by:
numJoins in interface Joiner
Returns:
an int


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