com.amazonaws.services.dynamodbv2.streamsadapter.leases

Class StreamsLeaseTaker<T extends com.amazonaws.services.kinesis.leases.impl.Lease>

java.lang.Object

com.amazonaws.services.dynamodbv2.streamsadapter.leases.StreamsLeaseTaker<T>

All Implemented Interfaces:

com.amazonaws.services.kinesis.leases.interfaces.ILeaseTaker<T>

public final class StreamsLeaseTaker<T extends com.amazonaws.services.kinesis.leases.impl.Lease>
extends java.lang.Object
implements com.amazonaws.services.kinesis.leases.interfaces.ILeaseTaker<T>

DynamoDBStreams implementation of ILeaseTaker. Contains logic for taking and load-balancing(taking and evicting) leases.

Constructor Summary

Constructors

Constructor and Description
StreamsLeaseTaker(com.amazonaws.services.kinesis.leases.interfaces.ILeaseManager<T> leaseManager, java.lang.String workerIdentifier, long leaseDurationMillis)

Method Summary

Modifier and Type	Method and Description
java.lang.String	getWorkerIdentifier()
StreamsLeaseTaker<T>	maxLeasesForWorker(int maxLeasesForWorker) Worker will not acquire more than the specified max number of leases even if there are more shards that need to be processed.
java.util.Map<java.lang.String,T>	takeLeases()

Methods inherited from class java.lang.Object

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

Constructor Detail

StreamsLeaseTaker

public StreamsLeaseTaker(com.amazonaws.services.kinesis.leases.interfaces.ILeaseManager<T> leaseManager,
                         java.lang.String workerIdentifier,
                         long leaseDurationMillis)

Method Detail

maxLeasesForWorker

public StreamsLeaseTaker<T> maxLeasesForWorker(int maxLeasesForWorker)

Worker will not acquire more than the specified max number of leases even if there are more shards that need to be processed. This can be used in scenarios where a worker is resource constrained or to prevent lease thrashing when small number of workers pick up all leases for small amount of time during deployment. Note that setting a low value may cause data loss (e.g. if there aren't enough Workers to make progress on all shards). When setting the value for this property, one must ensure enough workers are present to process shards and should consider future resharding, child shards that may be blocked on parent shards, some workers becoming unhealthy, etc.

Parameters:

maxLeasesForWorker - Max leases this Worker can handle at a time

Returns:

LeaseTaker

takeLeases

public java.util.Map<java.lang.String,T> takeLeases()
                                             throws com.amazonaws.services.kinesis.leases.exceptions.DependencyException,
                                                    com.amazonaws.services.kinesis.leases.exceptions.InvalidStateException

Specified by:

takeLeases in interface com.amazonaws.services.kinesis.leases.interfaces.ILeaseTaker<T extends com.amazonaws.services.kinesis.leases.impl.Lease>

Throws:

com.amazonaws.services.kinesis.leases.exceptions.DependencyException

com.amazonaws.services.kinesis.leases.exceptions.InvalidStateException

getWorkerIdentifier

public java.lang.String getWorkerIdentifier()

Specified by:

getWorkerIdentifier in interface com.amazonaws.services.kinesis.leases.interfaces.ILeaseTaker<T extends com.amazonaws.services.kinesis.leases.impl.Lease>