cascading.pipe.joiner
Class InnerJoin

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

public class InnerJoin
extends BaseJoiner

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

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
static class InnerJoin.JoinIterator
           
 
Constructor Summary
InnerJoin()
           
InnerJoin(Fields fieldDeclaration)
           
 
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 cascading.pipe.joiner.BaseJoiner
getFieldDeclaration
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

InnerJoin

public InnerJoin()

InnerJoin

@ConstructorProperties(value="fieldDeclaration")
public InnerJoin(Fields fieldDeclaration)
Method Detail

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

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


Copyright © 2007-2015 Concurrent, Inc. All Rights Reserved.