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DefaultJoinStrategy (Apache Crunch 0.10.0 API)

org.apache.crunch.lib.join
Class DefaultJoinStrategy<K,U,V>

java.lang.Object
  extended by org.apache.crunch.lib.join.DefaultJoinStrategy<K,U,V>
All Implemented Interfaces:
Serializable, JoinStrategy<K,U,V>

public class DefaultJoinStrategy<K,U,V>
extends Object
implements JoinStrategy<K,U,V>

Default join strategy that simply sends all data through the map, shuffle, and reduce phase.

This join strategy is full-featured (i.e. all methods are available), but is not highly efficient due to its passing all data through the shuffle phase.

See Also:
Serialized Form

Constructor Summary
DefaultJoinStrategy()
           
DefaultJoinStrategy(int numReducers)
           
 
Method Summary
 PTable<K,Pair<U,V>> join(PTable<K,U> left, PTable<K,V> right, JoinFn<K,U,V> joinFn)
          Perform a default join on the given PTable instances using a user-specified JoinFn.
 PTable<K,Pair<U,V>> join(PTable<K,U> left, PTable<K,V> right, JoinType joinType)
          Join two tables with the given join type.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DefaultJoinStrategy

public DefaultJoinStrategy()

DefaultJoinStrategy

public DefaultJoinStrategy(int numReducers)
Method Detail

join

public PTable<K,Pair<U,V>> join(PTable<K,U> left,
                                PTable<K,V> right,
                                JoinType joinType)
Description copied from interface: JoinStrategy
Join two tables with the given join type.

Specified by:
join in interface JoinStrategy<K,U,V>
Parameters:
left - left table to be joined
right - right table to be joined
joinType - type of join to perform
Returns:
joined tables

join

public PTable<K,Pair<U,V>> join(PTable<K,U> left,
                                PTable<K,V> right,
                                JoinFn<K,U,V> joinFn)
Perform a default join on the given PTable instances using a user-specified JoinFn.

Parameters:
left - left table to be joined
right - right table to be joined
joinFn - The user-specified implementation of the JoinFn class
Returns:
joined tables


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