Cosid Manual Integration

Integrate CosId Programmatically

Provide code that compiles against the user's CosId version. Prefer direct constructors for fixed local inputs and backend factories for distributed state.

Workflow

1. Confirm the target version and chosen strategy. Use $cosid-strategy-guide only when the strategy is undecided.
2. Identify the uniqueness authority: fixed machine ID, StatefulSet ordinal, distributed machine-ID backend, or segment backend.
3. Construct the smallest generator that satisfies the requirement.
4. Own every created client, guarder, executor, and distributor for its full lifecycle.
5. Add one focused check for uniqueness, local monotonicity, parsing, restart, or clock rollback.

When a CosId checkout is available, verify signatures in cosid-core/src/main/java/me/ahoo/cosid/ and use existing backend factories and tests as examples. Do not copy older README snippets without checking the current source.

SnowflakeId with a Fixed Machine ID

Use this only when deployment automation guarantees a unique value per live instance.

int machineId = 1;
SnowflakeId idGenerator = new ClockSyncSnowflakeId(
    new MillisecondSnowflakeId(machineId)
);

long id = idGenerator.generate();

Use SecondSnowflakeId only for a deliberate second-based bit layout. Use SafeJavaScriptSnowflakeId.ofMillisecond(machineId) when a numeric ID must stay within JavaScript's safe integer range; otherwise serialize ordinary IDs as strings.

Distributed Machine-ID Allocation

Create the backend-specific MachineIdDistributor, then allocate with the exact namespace, machine bits, instance identity, and lease:

static SnowflakeId createSnowflake(MachineIdDistributor distributor) {
    String namespace = "order-service";
    InstanceId instanceId = InstanceId.of("10.0.0.12:8080", false);
    Duration lease = Duration.ofMinutes(5);

    MachineState state = distributor.distribute(
        namespace,
        10,
        instanceId,
        lease
    );
    return new ClockSyncSnowflakeId(
        new MillisecondSnowflakeId(state.getMachineId())
    );
}

The snippet shows allocation, not heartbeat ownership. For expiring distributed leases, wrap allocation with GuardDistribute, run a DefaultMachineIdGuarder, stop it during shutdown, and call distributor.revert(namespace, instanceId) after stopping the guarder. Gate readiness and generation on guarder.hasFailure() because the guarder records heartbeat failure but does not stop ID generation. Shut down any ScheduledExecutorService created by the application after stopping the guarder. Pass stable: true only for a stable deployment identity such as a StatefulSet slot; stable instances retain their machine-ID claim instead of being recycled by the lease cutoff. Use local state storage only when the filesystem follows that stable identity; it helps reclaim the previous machine ID and prevents clock regression after restart.

For a fixed manual ID through the distributor API, use the real constructor:

MachineIdDistributor distributor = new ManualMachineIdDistributor(
    1,
    MachineStateStorage.LOCAL,
    ClockBackwardsSynchronizer.DEFAULT
);

Segment Generators

Obtain the distributor from the selected backend's IdSegmentDistributorFactory and keep the namespace/name/offset/step definition explicit:

static SegmentId createSegment(IdSegmentDistributorFactory distributorFactory) {
    IdSegmentDistributorDefinition definition =
        new IdSegmentDistributorDefinition("order-service", "order", 0, 100);
    IdSegmentDistributor distributor = distributorFactory.create(definition);
    return new SegmentChainId(distributor);
}

Use new DefaultSegmentId(distributor) instead when synchronous rollover is preferred. SegmentChainId uses PrefetchWorkerExecutorService.DEFAULT, which installs a JVM shutdown hook; if the application supplies its own executor, shut that executor down explicitly.

Segment IDs are monotonic only within one generator. Distributed ranges provide global uniqueness and trend ordering, not strict global generation-time order.

String Conversion

Wrap long generators with the matching string decorator instead of reimplementing generation:

IdConverter converter = new PrefixIdConverter(
    "ORD-",
    Radix62IdConverter.PAD_START
);
SnowflakeId stringSnowflake = new StringSnowflakeId(snowflakeId, converter);
SegmentId stringSegment = new StringSegmentId(segmentId, converter);

Call generateAsString() on the wrapper and test converter.asLong() when round-trip parsing is required. CosIdGenerator does not support IdConverter; select or implement its CosIdIdStateParser instead.

CosIdGenerator

CosIdGenerator produces strings; calling generate() throws UnsupportedOperationException.

CosIdGenerator generator = new ClockSyncCosIdGenerator(
    new Radix62CosIdGenerator(machineId)
);
String id = generator.generateAsString();

Allocate machineId with the same uniqueness and lifecycle rules as SnowflakeId.

Boundaries and Checks

• Keep one namespace per independent allocation domain and one stable instance identity per deployment slot.
• Reject machine IDs outside the configured bit range before starting traffic.
• Do not claim global monotonicity for segment generators or global total order for clock-based generators.
• Keep custom epoch, timestamp unit, bit layout, parser, and sharding converter aligned.
• Close backend clients created by the application. Do not close shared framework clients that the application does not own.
• Test with at least two simulated instances when correctness depends on distributed uniqueness.

Response Contract

Return the required module dependencies, exact imports and constructors, lifecycle ownership, one runnable check, and no unrelated Spring Boot configuration.