com.google.appengine.tools.mapreduce

Interface Sharder

All Superinterfaces:

Serializable

All Known Implementing Classes:

HashingSharder

public interface Sharder
extends Serializable

Used to determine which shard an item belongs to. This is used when emitting data from Map to specify which reduce shard it should go to. The only criteria that is required is that the same key always map to the same shard.

Method Summary

Methods

Modifier and Type	Method and Description
int	getNumShards()
int	getShardForKey(ByteBuffer key)

Method Detail

getNumShards

int getNumShards()

Returns:

the number of shards that are items may be assigned to.

getShardForKey

int getShardForKey(ByteBuffer key)

Parameters:

key - The serialized key. (The ByteBuffer should be unmodified by the implementation)

Returns:

a number between 0 and numShards-1 inclusive