org.apache.hadoop.mapreduce.lib.partition

クラス TotalOrderPartitioner<K,V>

java.lang.Object

org.apache.hadoop.mapreduce.Partitioner<K,V>

org.apache.hadoop.mapreduce.lib.partition.TotalOrderPartitioner<K,V>

すべての実装されたインタフェース:

Configurable

直系の既知のサブクラス:

TotalOrderPartitioner

@InterfaceAudience.Public
 @InterfaceStability.Stable
public class TotalOrderPartitioner<K,V>
extends Partitioner<K,V>
implements Configurable

Partitioner effecting a total order by reading split points from an externally generated source.

フィールドのサマリー

フィールド

修飾子とタイプ	フィールドと説明
static String	DEFAULT_PATH
static String	MAX_TRIE_DEPTH
static String	NATURAL_ORDER
static String	PARTITIONER_PATH

コンストラクタのサマリー

コンストラクタ

コンストラクタと説明
TotalOrderPartitioner()

メソッドのサマリー

修飾子とタイプ	メソッドと説明
Configuration	getConf() Return the configuration used by this object.
int	getPartition(K key, V value, int numPartitions) Get the partition number for a given key (hence record) given the total number of partitions i.e. number of reduce-tasks for the job.
static String	getPartitionFile(Configuration conf) Get the path to the SequenceFile storing the sorted partition keyset.
void	setConf(Configuration conf) Read in the partition file and build indexing data structures.
static void	setPartitionFile(Configuration conf, Path p) Set the path to the SequenceFile storing the sorted partition keyset.

クラスから継承されたメソッド java.lang.Object

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

フィールドの詳細

DEFAULT_PATH

public static final String DEFAULT_PATH

関連項目:

定数フィールド値

PARTITIONER_PATH

public static final String PARTITIONER_PATH

関連項目:

定数フィールド値

MAX_TRIE_DEPTH

public static final String MAX_TRIE_DEPTH

関連項目:

定数フィールド値

NATURAL_ORDER

public static final String NATURAL_ORDER

関連項目:

定数フィールド値

コンストラクタの詳細

TotalOrderPartitioner

public TotalOrderPartitioner()

メソッドの詳細

setConf

public void setConf(Configuration conf)

Read in the partition file and build indexing data structures. If the keytype is BinaryComparable and total.order.partitioner.natural.order is not false, a trie of the first total.order.partitioner.max.trie.depth(2) + 1 bytes will be built. Otherwise, keys will be located using a binary search of the partition keyset using the RawComparator defined for this job. The input file must be sorted with the same comparator and contain JobContextImpl.getNumReduceTasks() - 1 keys.

定義:

setConf インタフェース内 Configurable

getConf

public Configuration getConf()

インタフェースからコピーされた説明: Configurable

Return the configuration used by this object.

定義:

getConf インタフェース内 Configurable

getPartition

public int getPartition(K key,
                        V value,
                        int numPartitions)

クラスからコピーされた説明: Partitioner

Get the partition number for a given key (hence record) given the total number of partitions i.e. number of reduce-tasks for the job.

Typically a hash function on a all or a subset of the key.

定義:

getPartition クラス内 Partitioner<K,V>

パラメータ:

key - the key to be partioned.

value - the entry value.

numPartitions - the total number of partitions.

戻り値:

the partition number for the key.

setPartitionFile

public static void setPartitionFile(Configuration conf,
                                    Path p)

Set the path to the SequenceFile storing the sorted partition keyset. It must be the case that for R reduces, there are R-1 keys in the SequenceFile.

getPartitionFile

public static String getPartitionFile(Configuration conf)

Get the path to the SequenceFile storing the sorted partition keyset.

関連項目:

setPartitionFile(Configuration, Path)