software.amazon.kinesis.leases

Class Lease

java.lang.Object

software.amazon.kinesis.leases.Lease

public class Lease
extends Object

This class contains data pertaining to a Lease. Distributed systems may use leases to partition work across a fleet of workers. Each unit of work (identified by a leaseKey) has a corresponding Lease. Every worker will contend for all leases - only one worker will successfully take each one. The worker should hold the lease until it is ready to stop processing the corresponding unit of work, or until it fails. When the worker stops holding the lease, another worker will take and hold the lease.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Lease(Lease lease) Copy constructor, used by clone().
	Lease(String leaseKey, String leaseOwner, Long leaseCounter, UUID concurrencyToken, Long lastCounterIncrementNanos, ExtendedSequenceNumber checkpoint, ExtendedSequenceNumber pendingCheckpoint, Long ownerSwitchesSinceCheckpoint, Set<String> parentShardIds)

Method Summary

Modifier and Type	Method and Description
void	checkpoint(ExtendedSequenceNumber checkpoint) Sets checkpoint.
void	concurrencyToken(UUID concurrencyToken) Sets concurrencyToken.
Lease	copy() Returns a deep copy of this object.
boolean	isExpired(long leaseDurationNanos, long asOfNanos)
void	lastCounterIncrementNanos(Long lastCounterIncrementNanos) Sets lastCounterIncrementNanos
void	leaseCounter(Long leaseCounter) Sets leaseCounter.
void	leaseKey(String leaseKey) Sets leaseKey.
void	leaseOwner(String leaseOwner) Sets leaseOwner.
void	ownerSwitchesSinceCheckpoint(Long ownerSwitchesSinceCheckpoint) Sets ownerSwitchesSinceCheckpoint.
Set<String>	parentShardIds()
void	parentShardIds(Collection<String> parentShardIds) Sets parentShardIds.
void	pendingCheckpoint(ExtendedSequenceNumber pendingCheckpoint) Sets pending checkpoint.
void	update(Lease lease) Updates this Lease's mutable, application-specific fields based on the passed-in lease object.

Methods inherited from class java.lang.Object

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

Constructor Detail

Lease

protected Lease(Lease lease)

Copy constructor, used by clone().

Parameters:

lease - lease to copy

Lease

public Lease(String leaseKey,
             String leaseOwner,
             Long leaseCounter,
             UUID concurrencyToken,
             Long lastCounterIncrementNanos,
             ExtendedSequenceNumber checkpoint,
             ExtendedSequenceNumber pendingCheckpoint,
             Long ownerSwitchesSinceCheckpoint,
             Set<String> parentShardIds)

Method Detail

parentShardIds

public Set<String> parentShardIds()

Returns:

shardIds that parent this lease. Used for resharding.

update

public void update(Lease lease)

Updates this Lease's mutable, application-specific fields based on the passed-in lease object. Does not update fields that are internal to the leasing library (leaseKey, leaseOwner, leaseCounter).

Parameters:

lease -

isExpired

public boolean isExpired(long leaseDurationNanos,
                         long asOfNanos)

Parameters:

leaseDurationNanos - duration of lease in nanoseconds

asOfNanos - time in nanoseconds to check expiration as-of

Returns:

true if lease is expired as-of given time, false otherwise

lastCounterIncrementNanos

public void lastCounterIncrementNanos(Long lastCounterIncrementNanos)

Sets lastCounterIncrementNanos

Parameters:

lastCounterIncrementNanos - last renewal in nanoseconds since the epoch

concurrencyToken

public void concurrencyToken(@NonNull
                             UUID concurrencyToken)

Sets concurrencyToken.

Parameters:

concurrencyToken - may not be null

leaseKey

public void leaseKey(@NonNull
                     String leaseKey)

Sets leaseKey. LeaseKey is immutable once set.

Parameters:

leaseKey - may not be null.

leaseCounter

public void leaseCounter(@NonNull
                         Long leaseCounter)

Sets leaseCounter.

Parameters:

leaseCounter - may not be null

checkpoint

public void checkpoint(@NonNull
                       ExtendedSequenceNumber checkpoint)

Sets checkpoint.

Parameters:

checkpoint - may not be null

pendingCheckpoint

public void pendingCheckpoint(ExtendedSequenceNumber pendingCheckpoint)

Sets pending checkpoint.

Parameters:

pendingCheckpoint - can be null

ownerSwitchesSinceCheckpoint

public void ownerSwitchesSinceCheckpoint(@NonNull
                                         Long ownerSwitchesSinceCheckpoint)

Sets ownerSwitchesSinceCheckpoint.

Parameters:

ownerSwitchesSinceCheckpoint - may not be null

parentShardIds

public void parentShardIds(@NonNull
                           Collection<String> parentShardIds)

Sets parentShardIds.

Parameters:

parentShardIds - may not be null

leaseOwner

public void leaseOwner(String leaseOwner)

Sets leaseOwner.

Parameters:

leaseOwner - may be null.

copy

public Lease copy()

Returns a deep copy of this object. Type-unsafe - there aren't good mechanisms for copy-constructing generics.

Returns:

A deep copy of this object.