JooqContextsTests.kt

package com.gildedrose

import com.gildedrose.domain.StockList
import com.gildedrose.foundation.magic
import com.gildedrose.persistence.*
import dev.forkhandles.result4k.Result
import dev.forkhandles.result4k.Success
import org.jooq.DSLContext
import org.junit.jupiter.api.Test

class JooqContextsTests {

    val items = NewItems()

    @Test
    fun `two transactions`() {
        with(Persistence(testDslContext)) {
            items.save(initialStockList)
            items.load()
        }
    }

    @Test
    fun `one transaction`() {
        with(Persistence(testDslContext)) {
            inNewOrExistingTX {
                items.save(initialStockList)
                items.load()
            }
        }
    }

    @Test
    fun `nested transaction with savepoints`() {
        with(Persistence(testDslContext)) {
            inNewOrExistingTX {
                inNewTX {
                    items.save(initialStockList)
                }
                items.load()
            }
        }
    }
}

data class Persistence(
    val dslContext: DSLContext,
    val isInTX: Boolean = false
)

context(Persistence)
fun <R> inNewOrExistingTX(f: context(Persistence)() -> R): R = when {
    isInTX -> f(magic())
    else -> dslContext.transactionResult { trx ->
        f(Persistence(trx.dsl(), isInTX = true))
    }
}

context(Persistence)
fun <R> inNewTX(f: context(Persistence)() -> R): R =
    dslContext.transactionResult { trx ->
        f(Persistence(trx.dsl(), isInTX = true))
    }

class NewItems {
    context(Persistence)
    fun save(stockList: StockList)
        : Result<StockList, StockListLoadingError.IOError> = inNewOrExistingTX {
        dslContext.save(stockList)
        Success(stockList)
    }

    context(Persistence)
    fun load(): Result<StockList, StockListLoadingError> = inNewOrExistingTX {
        Success(dslContext.load())
    }
}