org.apache.bookkeeper.client

Interface DistributionSchedule

All Known Implementing Classes:

RoundRobinDistributionSchedule

public interface DistributionSchedule

This interface determins how entries are distributed among bookies.

Every entry gets replicated to some number of replicas. The first replica for an entry is given a replicaIndex of 0, and so on. To distribute write load, not all entries go to all bookies. Given an entry-id and replica index, an DistributionSchedule determines which bookie that replica should go to.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	DistributionSchedule.AckSet An ack set represents the set of bookies from which a response must be received so that an entry can be considered to be replicated on a quorum.
static interface	DistributionSchedule.QuorumCoverageSet Interface to keep track of which bookies in an ensemble, an action has been performed for.
static interface	DistributionSchedule.WriteSet A write set represents the set of bookies to which a request will be written.

Field Summary

Fields

Modifier and Type	Field and Description
static DistributionSchedule.WriteSet	NULL_WRITE_SET

Method Summary

Modifier and Type	Method and Description
DistributionSchedule.AckSet	getAckSet() Returns an ackset object, responses should be checked against this.
DistributionSchedule.QuorumCoverageSet	getCoverageSet()
DistributionSchedule.AckSet	getEnsembleAckSet() Returns an ackset object useful to wait for all bookies in the ensemble, responses should be checked against this.
DistributionSchedule.WriteSet	getEnsembleSet(long entryId) Return the set of bookies indices to send the messages to the whole ensemble.
java.util.BitSet	getEntriesStripedToTheBookie(int bookieIndex, long startEntryId, long lastEntryId) Get the bitset representing the entries from entry 'startEntryId' to 'lastEntryId', that would be striped to the bookie with index - bookieIndex.
DistributionSchedule.WriteSet	getWriteSet(long entryId) Return the set of bookie indices to send the message to.
boolean	hasEntry(long entryId, int bookieIndex) Whether entry presents on given bookie index.

Field Detail

NULL_WRITE_SET

static final DistributionSchedule.WriteSet NULL_WRITE_SET

Method Detail

getWriteSet

DistributionSchedule.WriteSet getWriteSet(long entryId)

Return the set of bookie indices to send the message to.

getEnsembleSet

DistributionSchedule.WriteSet getEnsembleSet(long entryId)

Return the set of bookies indices to send the messages to the whole ensemble.

Parameters:

entryId - entry id used to calculate the ensemble.

Returns:

the set of bookies indices to send the request.

getAckSet

DistributionSchedule.AckSet getAckSet()

Returns an ackset object, responses should be checked against this.

getEnsembleAckSet

DistributionSchedule.AckSet getEnsembleAckSet()

Returns an ackset object useful to wait for all bookies in the ensemble, responses should be checked against this.

getCoverageSet

DistributionSchedule.QuorumCoverageSet getCoverageSet()

hasEntry

boolean hasEntry(long entryId,
                 int bookieIndex)

Whether entry presents on given bookie index.

Parameters:

entryId - - entryId to check the presence on given bookie index

bookieIndex - - bookie index on which it need to check the possible presence of the entry

Returns:

true if it has entry otherwise false.

getEntriesStripedToTheBookie

java.util.BitSet getEntriesStripedToTheBookie(int bookieIndex,
                                              long startEntryId,
                                              long lastEntryId)

Get the bitset representing the entries from entry 'startEntryId' to 'lastEntryId', that would be striped to the bookie with index - bookieIndex. Value of the bit with the 'bitIndex+n', indicate whether entry with entryid 'startEntryId+n' is striped to this bookie or not.

Parameters:

bookieIndex - index of the bookie in the ensemble starting with 0

startEntryId - starting entryid

lastEntryId - last entryid

Returns:

the bitset representing the entries that would be striped to the bookie