Package at.aimon.session.postgres

Class PostgresConversationLock

java.lang.Object

at.aimon.session.postgres.PostgresConversationLock

All Implemented Interfaces:

at.aimon.session.web.spi.ConversationLock

public final class PostgresConversationLock
extends Object
implements at.aimon.session.web.spi.ConversationLock

Postgres-backed ConversationLock per design §4.1.

Row-level lease with a separate fencing-token counter — no pg_advisory_lock. The conversation_lock_fence table issues a monotonically increasing token per conversation; the conversation_lock row is upserted with ON CONFLICT DO UPDATE WHERE lease_expires_at < now() so a stale lease gets stomped while a live lease is left alone. RETURNING fencing_token after the upsert tells the caller whether they won the race (token matches the freshly-reserved one) or another holder still owns the row (return value differs / nothing returned).

Failure semantics:

• Lock held by another holder → empty Optional from tryAcquire(at.aimon.core.agent.conversation.ConversationId, java.lang.String, java.time.Duration).
• JDBC failure → ConversationLockException.

Nested Class Summary

Nested classes/interfaces inherited from interface at.aimon.session.web.spi.ConversationLock

at.aimon.session.web.spi.ConversationLock.LockHandle

Constructor Summary

Constructors

Constructor	Description
PostgresConversationLock(DataSource dataSource)
PostgresConversationLock(DataSource dataSource, Clock clock)

Method Summary

Modifier and Type	Method	Description
boolean	extend(at.aimon.session.web.spi.ConversationLock.LockHandle handle, Duration lease)
void	release(at.aimon.session.web.spi.ConversationLock.LockHandle handle)
Optional<at.aimon.session.web.spi.ConversationLock.LockHandle>	tryAcquire(at.aimon.core.agent.conversation.ConversationId id, String holderId, Duration lease)

Methods inherited from class java.lang.Object

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

Constructor Details

PostgresConversationLock

public PostgresConversationLock(DataSource dataSource)

PostgresConversationLock

public PostgresConversationLock(DataSource dataSource,
 Clock clock)

Method Details

tryAcquire

public Optional<at.aimon.session.web.spi.ConversationLock.LockHandle> tryAcquire(at.aimon.core.agent.conversation.ConversationId id,
 String holderId,
 Duration lease)

Specified by:

tryAcquire in interface at.aimon.session.web.spi.ConversationLock

extend

public boolean extend(at.aimon.session.web.spi.ConversationLock.LockHandle handle,
 Duration lease)

Specified by:

extend in interface at.aimon.session.web.spi.ConversationLock

release

public void release(at.aimon.session.web.spi.ConversationLock.LockHandle handle)

Specified by:

release in interface at.aimon.session.web.spi.ConversationLock