org.apache.bookkeeper.mledger.impl

Class NullLedgerOffloader

java.lang.Object

org.apache.bookkeeper.mledger.impl.NullLedgerOffloader

All Implemented Interfaces:

LedgerOffloader

public class NullLedgerOffloader
extends Object
implements LedgerOffloader

Null implementation that throws an error on any invokation.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.bookkeeper.mledger.LedgerOffloader

LedgerOffloader.OffloadHandle, LedgerOffloader.OffloadResult

Field Summary

Fields

Modifier and Type	Field and Description
static NullLedgerOffloader	INSTANCE

Fields inherited from interface org.apache.bookkeeper.mledger.LedgerOffloader

METADATA_SOFTWARE_GITSHA_KEY, METADATA_SOFTWARE_VERSION_KEY

Constructor Summary

Constructors

Constructor and Description
NullLedgerOffloader()

Method Summary

Modifier and Type	Method and Description
void	close() Close the resources if necessary
CompletableFuture<Void>	deleteOffloaded(long ledgerId, UUID uid, Map<String,String> offloadDriverMetadata) Delete a ledger from long term storage.
String	getOffloadDriverName() Get offload driver name.
OffloadPolicies	getOffloadPolicies() Get offload policies of this LedgerOffloader
CompletableFuture<Void>	offload(org.apache.bookkeeper.client.api.ReadHandle ledger, UUID uid, Map<String,String> extraMetadata) Offload the passed in ledger to longterm storage.
CompletableFuture<org.apache.bookkeeper.client.api.ReadHandle>	readOffloaded(long ledgerId, UUID uid, Map<String,String> offloadDriverMetadata) Create a ReadHandle which can be used to read a ledger back from longterm storage.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.bookkeeper.mledger.LedgerOffloader

deleteOffloaded, getOffloadDriverMetadata, readOffloaded, streamingOffload

Field Detail

INSTANCE

public static NullLedgerOffloader INSTANCE

Constructor Detail

NullLedgerOffloader

public NullLedgerOffloader()

Method Detail

getOffloadDriverName

public String getOffloadDriverName()

Description copied from interface: LedgerOffloader

Get offload driver name.

Specified by:

getOffloadDriverName in interface LedgerOffloader

Returns:

offload driver name.

offload

public CompletableFuture<Void> offload(org.apache.bookkeeper.client.api.ReadHandle ledger,
                                       UUID uid,
                                       Map<String,String> extraMetadata)

Description copied from interface: LedgerOffloader

Offload the passed in ledger to longterm storage. Metadata passed in is for inspection purposes only and should be stored alongside the ledger data. When the returned future completes, the ledger has been persisted to the longterm storage, so it is safe to delete the original copy in bookkeeper. The uid is used to identify an attempt to offload. The implementation should use this to deterministically generate a unique name for the offloaded object. This uid will be stored in the managed ledger metadata before attempting the call to offload(). If a subsequent or concurrent call to offload() finds a uid in the metadata, it will attempt to cleanup this attempt with a call to #deleteOffloaded(ReadHandle,UUID). Once the offload attempt completes, the managed ledger will update its metadata again, to record the completion, ensuring that subsequent calls will not attempt to offload the same ledger again.

Specified by:

offload in interface LedgerOffloader

Parameters:

ledger - the ledger to offload

uid - unique id to identity this offload attempt

extraMetadata - metadata to be stored with the offloaded ledger for informational purposes

Returns:

a future, which when completed, denotes that the offload has been successful.

readOffloaded

public CompletableFuture<org.apache.bookkeeper.client.api.ReadHandle> readOffloaded(long ledgerId,
                                                                                    UUID uid,
                                                                                    Map<String,String> offloadDriverMetadata)

Description copied from interface: LedgerOffloader

Create a ReadHandle which can be used to read a ledger back from longterm storage. The passed uid, will be match the uid of a previous successful call to #offload(ReadHandle,UUID,Map).

Specified by:

readOffloaded in interface LedgerOffloader

Parameters:

ledgerId - the ID of the ledger to load from longterm storage

uid - unique ID for previous successful offload attempt

offloadDriverMetadata - offload driver metadata

Returns:

a future, which when completed, returns a ReadHandle

deleteOffloaded

public CompletableFuture<Void> deleteOffloaded(long ledgerId,
                                               UUID uid,
                                               Map<String,String> offloadDriverMetadata)

Description copied from interface: LedgerOffloader

Delete a ledger from long term storage. The passed uid, will be match the uid of a previous call to #offload(ReadHandle,UUID,Map), which may or may not have been successful.

Specified by:

deleteOffloaded in interface LedgerOffloader

Parameters:

ledgerId - the ID of the ledger to delete from longterm storage

uid - unique ID for previous offload attempt

offloadDriverMetadata - offload driver metadata

Returns:

a future, which when completed, signifies that the ledger has been deleted

getOffloadPolicies

public OffloadPolicies getOffloadPolicies()

Description copied from interface: LedgerOffloader

Get offload policies of this LedgerOffloader

Specified by:

getOffloadPolicies in interface LedgerOffloader

Returns:

offload policies

close

public void close()

Description copied from interface: LedgerOffloader

Close the resources if necessary

Specified by:

close in interface LedgerOffloader