Transactors

A Transactor manages database connections and transactions. It provides a clean API for executing database operations with automatic connection and transaction lifecycle management.

Setting Up a Transactor

Java

// The Transactor manages connections and transactions
// You choose the strategy — it handles the lifecycle
var tx = connectionSource.transactor(Transactor.defaultStrategy());

// Everything inside runs in one transaction: begin, commit, close
List<ProductRow> products = tx.execute(conn ->
    Fragment.of("SELECT * FROM product WHERE price > ?")
        .param(PgTypes.numeric, minPrice)
        .query(ProductRow.rowParser.list())
        .runUnchecked(conn)
);

Kotlin

// The Transactor manages connections and transactions
val tx = connectionSource.transactor(Transactor.defaultStrategy())

// Everything inside runs in one transaction: begin, commit, close
val products: List<ProductRow> = tx.execute { conn ->
    Fragment.of("SELECT * FROM product WHERE price > ?")
        .param(PgTypes.numeric, minPrice)
        .query(ProductRow.rowParser.list())
        .runUnchecked(conn)
}

Scala

// The Transactor manages connections and transactions
val tx = connectionSource.transactor(Transactor.defaultStrategy())

// Everything inside runs in one transaction: begin, commit, close
val products: List[ProductRow] = tx.execute(conn =>
    sql"SELECT * FROM product WHERE price > ${PgTypes.numeric.encode(minPrice)}"
        .query(ProductRow.rowParser.list())
        .runUnchecked(conn)
)

Built-in Strategies

Strategy	Description
Transactor.defaultStrategy()	begin, commit, close
Transactor.autoCommitStrategy()	no transaction, just close
Transactor.rollbackOnErrorStrategy()	begin, commit on success, rollback on error, close
Transactor.testStrategy()	begin, rollback, close (for tests)

Custom Strategies

Define your own with explicit hooks:

Java

new Transactor.Strategy(
    conn -> conn.setAutoCommit(false),  // before
    Connection::commit,                  // after (success)
    throwable -> { /* handle error */ }, // oops
    Connection::close                    // always (finally)
);

Kotlin

Transactor.Strategy(
    { conn -> conn.autoCommit = false },  // before
    { conn -> conn.commit() },             // after (success)
    { throwable -> /* handle error */ },   // oops
    { conn -> conn.close() }               // always (finally)
)

Scala

Transactor.Strategy(
    conn => conn.setAutoCommit(false),  // before
    conn => conn.commit(),               // after (success)
    throwable => (),                     // oops
    conn => conn.close()                 // always (finally)
)