org.apache.crunch.lib

Class PTables

java.lang.Object

org.apache.crunch.lib.PTables

public class PTables
extends Object

Methods for performing common operations on PTables.

Constructor Summary

Constructors

Constructor and Description
PTables()

Method Summary

Methods

Modifier and Type	Method and Description
static <K,V> PTable<K,V>	asPTable(PCollection<Pair<K,V>> pcollect) Convert the given PCollection<Pair<K, V>> to a PTable<K, V>.
static <K,V> Pair<K,V>	getDetachedValue(PTableType<K,V> tableType, Pair<K,V> value) Create a detached value for a table Pair.
static <K,V> Pair<K,Iterable<V>>	getGroupedDetachedValue(PGroupedTableType<K,V> groupedTableType, Pair<K,Iterable<V>> value) Created a detached value for a PGroupedTable value.
static <K,V> PCollection<K>	keys(PTable<K,V> ptable) Extract the keys from the given PTable<K, V> as a PCollection<K>.
static <K,V> PCollection<V>	values(PTable<K,V> ptable) Extract the values from the given PTable<K, V> as a PCollection<V>.

Methods inherited from class java.lang.Object

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

Constructor Detail

PTables

public PTables()

Method Detail

asPTable

public static <K,V> PTable<K,V> asPTable(PCollection<Pair<K,V>> pcollect)

Convert the given PCollection<Pair<K, V>> to a PTable<K, V>.

Parameters:

pcollect - The PCollection to convert

Returns:

A PTable that contains the same data as the input PCollection

keys

public static <K,V> PCollection<K> keys(PTable<K,V> ptable)

Extract the keys from the given PTable<K, V> as a PCollection<K>.

Parameters:

ptable - The PTable

Returns:

A PCollection<K>

values

public static <K,V> PCollection<V> values(PTable<K,V> ptable)

Extract the values from the given PTable<K, V> as a PCollection<V>.

Parameters:

ptable - The PTable

Returns:

A PCollection<V>

getDetachedValue

public static <K,V> Pair<K,V> getDetachedValue(PTableType<K,V> tableType,
                               Pair<K,V> value)

Create a detached value for a table Pair.

Parameters:

tableType - The table type

value - The value from which a detached value is to be created

Returns:

The detached value

See Also:

PType.getDetachedValue(Object)

getGroupedDetachedValue

public static <K,V> Pair<K,Iterable<V>> getGroupedDetachedValue(PGroupedTableType<K,V> groupedTableType,
                                                Pair<K,Iterable<V>> value)

Created a detached value for a PGroupedTable value.

Parameters:

groupedTableType - The grouped table type

value - The value from which a detached value is to be created

Returns:

The detached value

See Also:

PType.getDetachedValue(Object)