com.linkedin.parseq.batching

Interface Batch<K,T>

Type Parameters:

K - Type of a Key

T - Type of a Value

All Known Implementing Classes:

BatchImpl

public interface Batch<K,T>

Batch represents a collection of keys related to each other in such a way that it is more efficient to compute values for those keys in bulk than computing value for each key individually. This class contains methods helpful in implementing bulk operation that completes Promises associated with keys.

Author:

Jaroslaw Odzga (jodzga@linkedin.com)

Method Summary

Modifier and Type	Method and Description
int	batchSize() Returns size of this batch.
void	done(K key, T value) Completes a Promise associated with given key with a value.
Set<Map.Entry<K,BatchImpl.BatchEntry<T>>>	entries()
void	fail(K key, Throwable error) Fails a Promise associated with given key with an error.
int	failAll(Throwable error) Fails all promises belonging to this batch with given error.
void	foreach(BiConsumer<K,com.linkedin.parseq.promise.SettablePromise<T>> consumer) Performs the given action for each element of the batch until all elements have been processed or the action throws an exception.
Set<K>	keys() Returns set of keys belonging to this batch.
int	keySize() Returns number of keys belonging to this batch.
Collection<BatchImpl.BatchEntry<T>>	values()

Method Detail

foreach

void foreach(BiConsumer<K,com.linkedin.parseq.promise.SettablePromise<T>> consumer)

Performs the given action for each element of the batch until all elements have been processed or the action throws an exception. Order in which elements are processed is unspecified. Exceptions thrown by the action are relayed to the caller.

Parameters:

consumer - action to be performed in each element of the batch

keys

Set<K> keys()

Returns set of keys belonging to this batch.

Returns:

set of keys belonging to this batch

keySize

int keySize()

Returns number of keys belonging to this batch.

Returns:

number of keys belonging to this batch.

batchSize

int batchSize()

Returns size of this batch. This number is not necessarily equal to the number of keys belonging to this batch. This number might be different than number of keys if BatchingStrategy.keySize(Object, Object) is defined.

Returns:

size of this batch.

done

void done(K key,
          T value)
   throws com.linkedin.parseq.promise.PromiseResolvedException

Completes a Promise associated with given key with a value. Throws PromiseResolvedException if Promise associated with given key has already been resolved.

Parameters:

key - key that identifies a Promise to be completed

value - value to complete Promise with

Throws:

com.linkedin.parseq.promise.PromiseResolvedException - if Promise associated with given key has already been resolved

fail

void fail(K key,
          Throwable error)
   throws com.linkedin.parseq.promise.PromiseResolvedException

Fails a Promise associated with given key with an error. Throws PromiseResolvedException if Promise associated with given key has already been resolved.

Parameters:

key - key that identifies a Promise to be completed

error - error to fail Promise with

Throws:

com.linkedin.parseq.promise.PromiseResolvedException - if Promise associated with given key has already been resolved

failAll

int failAll(Throwable error)

Fails all promises belonging to this batch with given error. If a promise belonging to this batch has already been completed then it is ignored by this method. This method guarantees that after it returns each Promise in this batch is either completed or failed.

Parameters:

error - error that all promises belonging to this batch will be failed with

Returns:

number of promises that were not failed because the promise has already been resolved; if this method returns 0 it means that it successfully failed all promises belonging to this batch with specified error

values

Collection<BatchImpl.BatchEntry<T>> values()

entries

Set<Map.Entry<K,BatchImpl.BatchEntry<T>>> entries()