software.amazon.kinesis.leases

Class Lease

java.lang.Object

software.amazon.kinesis.leases.Lease

Direct Known Subclasses:

MultiStreamLease

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) Deprecated.
	Lease(String leaseKey, String leaseOwner, Long leaseCounter, UUID concurrencyToken, Long lastCounterIncrementNanos, ExtendedSequenceNumber checkpoint, ExtendedSequenceNumber pendingCheckpoint, Long ownerSwitchesSinceCheckpoint, Set<String> parentShardIds, Set<String> childShardIds, byte[] pendingCheckpointState, HashKeyRangeForLease hashKeyRangeForLease)

Method Summary

Modifier and Type	Method and Description
String	actualOwner() Need to handle the case during graceful shutdown where leaseOwner isn't the current owner
boolean	blockedOnPendingCheckpoint(long currentTimeMillis) Check whether lease should be blocked on pending checkpoint.
void	checkpoint(@NonNull ExtendedSequenceNumber checkpoint) Sets checkpoint.
void	childShardIds(@NonNull Collection<String> childShardIds) Sets childShardIds.
void	concurrencyToken(@NonNull UUID concurrencyToken) Sets concurrencyToken.
Lease	copy() Returns a deep copy of this object.
void	hashKeyRange(HashKeyRangeForLease hashKeyRangeForLease) Set the hash range key for this shard.
boolean	isAvailable(long leaseDurationNanos, long asOfNanos)
boolean	isEligibleForGracefulShutdown() Check whether lease is eligible for graceful shutdown.
boolean	isExpired(long leaseDurationNanos, long asOfNanos)
void	lastCounterIncrementNanos(Long lastCounterIncrementNanos) Sets lastCounterIncrementNanos
void	leaseCounter(@NonNull Long leaseCounter) Sets leaseCounter.
void	leaseKey(@NonNull String leaseKey) Sets leaseKey.
void	leaseOwner(String leaseOwner) Sets leaseOwner.
void	ownerSwitchesSinceCheckpoint(@NonNull Long ownerSwitchesSinceCheckpoint) Sets ownerSwitchesSinceCheckpoint.
Set<String>	parentShardIds()
void	parentShardIds(@NonNull Collection<String> parentShardIds) Sets parentShardIds.
void	pendingCheckpoint(ExtendedSequenceNumber pendingCheckpoint) Sets pending checkpoint.
void	pendingCheckpointState(byte[] pendingCheckpointState) Sets pending checkpoint state.
boolean	shutdownRequested()
void	throughputKBps(double throughputKBps) Sets throughputKbps.
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

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

Deprecated.

Lease

public Lease(String leaseKey,
             String leaseOwner,
             Long leaseCounter,
             UUID concurrencyToken,
             Long lastCounterIncrementNanos,
             ExtendedSequenceNumber checkpoint,
             ExtendedSequenceNumber pendingCheckpoint,
             Long ownerSwitchesSinceCheckpoint,
             Set<String> parentShardIds,
             Set<String> childShardIds,
             byte[] pendingCheckpointState,
             HashKeyRangeForLease hashKeyRangeForLease)

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 -

isAvailable

public boolean isAvailable(long leaseDurationNanos,
                           long asOfNanos)

Parameters:

leaseDurationNanos - duration of lease in nanoseconds

asOfNanos - time in nanoseconds to check expiration as-of

Returns:

true if lease lease is ready to be taken

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

shutdownRequested

public boolean shutdownRequested()

Returns:

true if checkpoint owner is set. Indicating a requested shutdown.

blockedOnPendingCheckpoint

public boolean blockedOnPendingCheckpoint(long currentTimeMillis)

Check whether lease should be blocked on pending checkpoint. We DON'T block if - lease is expired (Expired lease should be assigned right away) OR ----- at this point we know lease is assigned ----- - lease is shardEnd (No more processing possible) OR - lease is NOT requested for shutdown OR - lease shutdown expired

Parameters:

currentTimeMillis - current time in milliseconds

Returns:

true if lease is blocked on pending checkpoint

isEligibleForGracefulShutdown

public boolean isEligibleForGracefulShutdown()

Check whether lease is eligible for graceful shutdown. It's eligible if - lease is still assigned (not expired) AND - lease is NOT shardEnd (No more processing possible AND - lease is NOT requested for shutdown

Returns:

true if lease is eligible for graceful shutdown

actualOwner

public String actualOwner()

Need to handle the case during graceful shutdown where leaseOwner isn't the current owner

Returns:

the actual owner

lastCounterIncrementNanos

public void lastCounterIncrementNanos(Long lastCounterIncrementNanos)

Sets lastCounterIncrementNanos

Parameters:

lastCounterIncrementNanos - last renewal in nanoseconds since the epoch

concurrencyToken

public void concurrencyToken(@NonNull
                             @NonNull UUID concurrencyToken)

Sets concurrencyToken.

Parameters:

concurrencyToken - may not be null

leaseKey

public void leaseKey(@NonNull
                     @NonNull String leaseKey)

Sets leaseKey. LeaseKey is immutable once set.

Parameters:

leaseKey - may not be null.

leaseCounter

public void leaseCounter(@NonNull
                         @NonNull Long leaseCounter)

Sets leaseCounter.

Parameters:

leaseCounter - may not be null

checkpoint

public void checkpoint(@NonNull
                       @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

pendingCheckpointState

public void pendingCheckpointState(byte[] pendingCheckpointState)

Sets pending checkpoint state.

Parameters:

pendingCheckpointState - can be null

ownerSwitchesSinceCheckpoint

public void ownerSwitchesSinceCheckpoint(@NonNull
                                         @NonNull Long ownerSwitchesSinceCheckpoint)

Sets ownerSwitchesSinceCheckpoint.

Parameters:

ownerSwitchesSinceCheckpoint - may not be null

parentShardIds

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

Sets parentShardIds.

Parameters:

parentShardIds - may not be null

childShardIds

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

Sets childShardIds.

Parameters:

childShardIds - may not be null

throughputKBps

public void throughputKBps(double throughputKBps)

Sets throughputKbps.

Parameters:

throughputKBps - may not be null

hashKeyRange

public void hashKeyRange(HashKeyRangeForLease hashKeyRangeForLease)

Set the hash range key for this shard.

Parameters:

hashKeyRangeForLease -

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.