Strategies

A Transactor.Strategy defines hooks that wrap every execution. The built-in strategies cover common patterns — this page covers customization.

Hook Lifecycle

Hook	When it runs
onBegin	Before your code — typically setAutoCommit(false)
onSuccess	After your code succeeds — typically commit
onFailure	When an exception is thrown (catch) — receives the connection and the throwable
onComplete	In all cases (finally) — typically close
listener	A QueryListener for observability (see Observability)

Custom Strategies

Build a strategy from scratch using replaceX methods — each one sets a single hook:

Kotlin

val customStrategy: Strategy =
    Strategy.empty()
        .replaceOnBegin { conn -> conn.autoCommit = false }
        .replaceOnSuccess(Connection::commit)
        .replaceOnFailure { _, _ -> /* handle error */ }
        .replaceOnComplete(Connection::close)

Java

Transactor.Strategy customStrategy =
    Transactor.Strategy.empty()
        .replaceOnBegin(conn -> conn.setAutoCommit(false))
        .replaceOnSuccess(Connection::commit)
        .replaceOnFailure((conn, throwable) -> { /* handle error */ })
        .replaceOnComplete(Connection::close);

Scala

val customStrategy: Transactor.Strategy =
  Strategy.empty()
    .replaceOnBegin(conn => conn.setAutoCommit(false))
    .replaceOnSuccess((conn: Connection) => conn.commit())
    .replaceOnFailure((_, _) => { /* handle error */ })
    .replaceOnComplete((conn: Connection) => conn.close())

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Strategy Merging

Use mergeX methods to compose hooks — both the existing and new hook run in order. mergeListener composes listeners:

Kotlin

val base: Strategy = Transactor.defaultStrategy()
val withLogging: Strategy = base.mergeListener(logger)

Java

Transactor.Strategy base = Transactor.defaultStrategy();
Transactor.Strategy withLogging = base.mergeListener(logger);

Scala

val base: Transactor.Strategy = Transactor.defaultStrategy()
val withLogging: Transactor.Strategy = base.mergeListener(logger)

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The mergeListener convenience on Transactor creates a derived transactor with the listener merged into its strategy:

Kotlin

val txWithLogging: Transactor = tx.mergeListener(logger)

Java

Transactor txWithLogging = tx.mergeListener(logger);

Scala

val txWithLogging: Transactor = tx.mergeListener(logger)

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