org.apache.crunch.lib

Class Cogroup

java.lang.Object

org.apache.crunch.lib.Cogroup

public class Cogroup
extends Object

Constructor Summary

Constructors

Constructor and Description
Cogroup()

Method Summary

Modifier and Type	Method and Description
static <K,U,V> PTable<K,TupleN>	cogroup(int numReducers, PTable<K,?> first, PTable<K,?>... rest) Co-groups an arbitrary number of PTable arguments with a user-specified degree of parallelism (a.k.a, number of reducers.) The largest table should come last in the ordering.
static <K,U,V> PTable<K,Pair<Collection<U>,Collection<V>>>	cogroup(int numReducers, PTable<K,U> left, PTable<K,V> right) Co-groups the two PTable arguments with a user-specified degree of parallelism (a.k.a, number of reducers.)
static <K,V1,V2,V3> PTable<K,Tuple3.Collect<V1,V2,V3>>	cogroup(int numReducers, PTable<K,V1> first, PTable<K,V2> second, PTable<K,V3> third) Co-groups the three PTable arguments with a user-specified degree of parallelism (a.k.a, number of reducers.)
static <K,V1,V2,V3,V4> PTable<K,Tuple4.Collect<V1,V2,V3,V4>>	cogroup(int numReducers, PTable<K,V1> first, PTable<K,V2> second, PTable<K,V3> third, PTable<K,V4> fourth) Co-groups the three PTable arguments with a user-specified degree of parallelism (a.k.a, number of reducers.)
static <K> PTable<K,TupleN>	cogroup(PTable<K,?> first, PTable<K,?>... rest) Co-groups an arbitrary number of PTable arguments.
static <K,U,V> PTable<K,Pair<Collection<U>,Collection<V>>>	cogroup(PTable<K,U> left, PTable<K,V> right) Co-groups the two PTable arguments.
static <K,V1,V2,V3> PTable<K,Tuple3.Collect<V1,V2,V3>>	cogroup(PTable<K,V1> first, PTable<K,V2> second, PTable<K,V3> third) Co-groups the three PTable arguments.
static <K,V1,V2,V3,V4> PTable<K,Tuple4.Collect<V1,V2,V3,V4>>	cogroup(PTable<K,V1> first, PTable<K,V2> second, PTable<K,V3> third, PTable<K,V4> fourth) Co-groups the three PTable arguments.

Methods inherited from class java.lang.Object

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

Constructor Detail

Cogroup

public Cogroup()

Method Detail

cogroup

public static <K,U,V> PTable<K,Pair<Collection<U>,Collection<V>>> cogroup(PTable<K,U> left,
                                                                          PTable<K,V> right)

Co-groups the two PTable arguments.

Parameters:

left - The left (smaller) PTable

right - The right (larger) PTable

Returns:

a PTable representing the co-grouped tables

cogroup

public static <K,U,V> PTable<K,Pair<Collection<U>,Collection<V>>> cogroup(int numReducers,
                                                                          PTable<K,U> left,
                                                                          PTable<K,V> right)

Co-groups the two PTable arguments with a user-specified degree of parallelism (a.k.a, number of reducers.)

Parameters:

numReducers - The number of reducers to use

left - The left (smaller) PTable

right - The right (larger) PTable

Returns:

A new PTable representing the co-grouped tables

cogroup

public static <K,V1,V2,V3> PTable<K,Tuple3.Collect<V1,V2,V3>> cogroup(PTable<K,V1> first,
                                                                      PTable<K,V2> second,
                                                                      PTable<K,V3> third)

Co-groups the three PTable arguments.

Parameters:

first - The smallest PTable

second - The second-smallest PTable

third - The largest PTable

Returns:

a PTable representing the co-grouped tables

cogroup

public static <K,V1,V2,V3> PTable<K,Tuple3.Collect<V1,V2,V3>> cogroup(int numReducers,
                                                                      PTable<K,V1> first,
                                                                      PTable<K,V2> second,
                                                                      PTable<K,V3> third)

Co-groups the three PTable arguments with a user-specified degree of parallelism (a.k.a, number of reducers.)

Parameters:

numReducers - The number of reducers to use

first - The smallest PTable

second - The second-smallest PTable

third - The largest PTable

Returns:

A new PTable representing the co-grouped tables

cogroup

public static <K,V1,V2,V3,V4> PTable<K,Tuple4.Collect<V1,V2,V3,V4>> cogroup(PTable<K,V1> first,
                                                                            PTable<K,V2> second,
                                                                            PTable<K,V3> third,
                                                                            PTable<K,V4> fourth)

Co-groups the three PTable arguments.

Parameters:

first - The smallest PTable

second - The second-smallest PTable

third - The largest PTable

Returns:

a PTable representing the co-grouped tables

cogroup

public static <K,V1,V2,V3,V4> PTable<K,Tuple4.Collect<V1,V2,V3,V4>> cogroup(int numReducers,
                                                                            PTable<K,V1> first,
                                                                            PTable<K,V2> second,
                                                                            PTable<K,V3> third,
                                                                            PTable<K,V4> fourth)

Co-groups the three PTable arguments with a user-specified degree of parallelism (a.k.a, number of reducers.)

Parameters:

numReducers - The number of reducers to use

first - The smallest PTable

second - The second-smallest PTable

third - The largest PTable

Returns:

A new PTable representing the co-grouped tables

cogroup

public static <K> PTable<K,TupleN> cogroup(PTable<K,?> first,
                                           PTable<K,?>... rest)

Co-groups an arbitrary number of PTable arguments. The largest table should come last in the ordering.

Parameters:

first - The first (smallest) PTable to co-group

rest - The other (larger) PTables to co-group

Returns:

a PTable representing the co-grouped tables

cogroup

public static <K,U,V> PTable<K,TupleN> cogroup(int numReducers,
                                               PTable<K,?> first,
                                               PTable<K,?>... rest)

Co-groups an arbitrary number of PTable arguments with a user-specified degree of parallelism (a.k.a, number of reducers.) The largest table should come last in the ordering.

Parameters:

numReducers - The number of reducers to use

first - The first (smallest) PTable to co-group

rest - The other (larger) PTables to co-group

Returns:

A new PTable representing the co-grouped tables