org.apache.samza.table.remote

Interface TableReadFunction<K,V>

Type Parameters:

K - the type of the key in this table

V - the type of the value in this table

All Superinterfaces:

ClosableFunction, InitableFunction, java.io.Serializable

@InterfaceStability.Unstable
public interface TableReadFunction<K,V>
extends java.io.Serializable, InitableFunction, ClosableFunction

A function object to be used with a remote readable table implementation. It encapsulates the functionality of reading table record(s) for a provided set of key(s).

Instances of TableReadFunction are meant to be serializable. ie. any non-serializable state (eg: network sockets) should be marked as transient and recreated inside readObject().

Implementations are expected to be thread-safe.

Method Summary

Modifier and Type	Method and Description
default V	get(K key) Fetch single table record for a specified key.
default java.util.Map<K,V>	getAll(java.util.Collection<K> keys) Fetch the table records for specified keys.
default java.util.concurrent.CompletableFuture<java.util.Map<K,V>>	getAllAsync(java.util.Collection<K> keys) Asynchronously fetch the table records for specified keys.
java.util.concurrent.CompletableFuture<V>	getAsync(K key) Asynchronously fetch single table record for a specified key.
boolean	isRetriable(java.lang.Throwable exception) Determine whether the current operation can be retried with the last thrown exception.

Methods inherited from interface org.apache.samza.operators.functions.InitableFunction

init

Methods inherited from interface org.apache.samza.operators.functions.ClosableFunction

close

Method Detail

get

default V get(K key)

Fetch single table record for a specified key. This method must be thread-safe. The default implementation calls getAsync and blocks on the completion afterwards.

Parameters:

key - key for the table record

Returns:

table record for the specified key

getAsync

java.util.concurrent.CompletableFuture<V> getAsync(K key)

Asynchronously fetch single table record for a specified key. This method must be thread-safe.

Parameters:

key - key for the table record

Returns:

CompletableFuture for the get request

getAll

default java.util.Map<K,V> getAll(java.util.Collection<K> keys)

Fetch the table records for specified keys. This method must be thread-safe. The default implementation calls getAllAsync and blocks on the completion afterwards.

Parameters:

keys - keys for the table records

Returns:

all records for the specified keys.

getAllAsync

default java.util.concurrent.CompletableFuture<java.util.Map<K,V>> getAllAsync(java.util.Collection<K> keys)

Asynchronously fetch the table records for specified keys. This method must be thread-safe. The default implementation calls getAsync for each key and return a combined future.

Parameters:

keys - keys for the table records

Returns:

CompletableFuture for the get request

isRetriable

boolean isRetriable(java.lang.Throwable exception)

Determine whether the current operation can be retried with the last thrown exception.

Parameters:

exception - exception thrown by a table operation

Returns:

whether the operation can be retried