Package me.ahoo.cosid.segment

Class AbstractIdSegmentDistributor

java.lang.Object

me.ahoo.cosid.segment.AbstractIdSegmentDistributor

All Implemented Interfaces:

Grouped, IdSegmentDistributor

Direct Known Subclasses:

JdbcIdSegmentDistributor, MongoIdSegmentDistributor, ProxyIdSegmentDistributor, SpringRedisIdSegmentDistributor, ZookeeperIdSegmentDistributor

public abstract class AbstractIdSegmentDistributor
extends Object
implements IdSegmentDistributor

Base of the IdSegmentDistributors: common properties and one rollback rule for every backend.

The max id this distributor got from the store must strictly move forward. If the store hands out a max id below last max id + step (restored from a backup, a lost Redis key, a manual edit), the range overlaps ids already issued, and nextMaxId(long) throws IdSegmentRollbackException (an IllegalStateException) instead of issuing duplicates. Subclasses only implement doNextMaxId(long).

Since:

3.4.0

Field Summary

Fields inherited from interface me.ahoo.cosid.segment.IdSegmentDistributor

DEFAULT_OFFSET, DEFAULT_SEGMENTS, DEFAULT_STEP

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	AbstractIdSegmentDistributor(String namespace, String name, long step)

Method Summary

Modifier and Type	Method	Description
protected abstract long	doNextMaxId(long step)	Ask the store for the next max id, step after the previous one.
long	getLastMaxId()	The largest max id this distributor got so far, 0 before the first one.
@NonNull String	getName()	Get the name for this distributor.
@NonNull String	getNamespace()	Get the namespace for this distributor.
long	getStep()	Get the step size for ID segments.
long	nextMaxId(long step)	Allocate the next maximum ID for the specified step size.

Methods inherited from class java.lang.Object

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

Methods inherited from interface me.ahoo.cosid.segment.grouped.Grouped

group

Methods inherited from interface me.ahoo.cosid.segment.IdSegmentDistributor

allowReset, getNamespacedName, getStep, nextIdSegment, nextIdSegment, nextIdSegment, nextIdSegmentChain, nextIdSegmentChain, nextMaxId

Constructor Details

AbstractIdSegmentDistributor

protected AbstractIdSegmentDistributor(String namespace,
 String name,
 long step)

Method Details

getNamespace

public @NonNull String getNamespace()

Description copied from interface: IdSegmentDistributor

Get the namespace for this distributor.

The namespace provides a logical grouping for ID segments, allowing multiple independent segment spaces within the same system.

Specified by:

getNamespace in interface IdSegmentDistributor

Returns:

The namespace

getName

public @NonNull String getName()

Description copied from interface: IdSegmentDistributor

Get the name for this distributor.

The name uniquely identifies this distributor within its namespace.

Specified by:

getName in interface IdSegmentDistributor

Returns:

The name

getStep

public long getStep()

Description copied from interface: IdSegmentDistributor

Get the step size for ID segments.

The step size determines how many IDs are allocated in each segment. Larger steps reduce coordination overhead but may lead to ID gaps.

Specified by:

getStep in interface IdSegmentDistributor

Returns:

The step size

getLastMaxId

public long getLastMaxId()

The largest max id this distributor got so far, 0 before the first one.

nextMaxId

public long nextMaxId(long step)

Description copied from interface: IdSegmentDistributor

Allocate the next maximum ID for the specified step size.

This method allocates a new range of IDs by returning the maximum ID in the allocated range. The range starts at the previous maximum plus one and ends at the returned value.

Specified by:

nextMaxId in interface IdSegmentDistributor

Parameters:

step - The step size for allocation

Returns:

The maximum ID in the allocated range

doNextMaxId

protected abstract long doNextMaxId(long step)

Ask the store for the next max id, step after the previous one.

Parameters:

step - the step, already validated

Returns:

the new max id