transactions

import com.couchbase.client.kotlin.Cluster
import com.couchbase.client.kotlin.Collection
import com.couchbase.client.kotlin.transactions.TransactionGetResult
import kotlin.random.Random
fun main() { 
   //sampleStart 
   // Assume two documents both contain integers.
// Subtract a value from the one document and add it to the other.
cluster.transactions.run {
    // The SDK may execute this lambda multiple times
    // if there are conflicts between transactions.
    // All logic related to the transaction must happen
    // inside this lambda.

    // Inside the lambda, `this` is a `TransactionAttemptContext`
    // with instance methods like `get`, `replace`, `insert`, `remove`,
    // and `query` for interacting with documents in a transactional way.
    // These are the only methods you should use to interact with documents
    // inside the transaction lambda.

    val source: TransactionGetResult = get(collection, sourceDocId)
    val dest: TransactionGetResult = get(collection, destDocId)

    val newSourceValue: Int = source.contentAs<Int>() - value
    val newDestValue: Int = dest.contentAs<Int>() + value

    replace(source, newSourceValue)

    // Throwing any exception triggers a rollback and causes
    // `transactions.run` to throw TransactionFailedException.
    if (Random.nextBoolean()) throw RuntimeException("simulated error")
    require(newSourceValue >= 0) { "transfer would result in negative source value" }
    require(newDestValue >= 0) { "transfer would result in dest value overflow" }

    replace(dest, newDestValue)
} 
   //sampleEnd
}