read

Executes the given action under the read lock of this lock.

@IgnorableReturnValueinline fun <T> ReentrantReadWriteLock.read(action: () -> T): T(source)

import java.util.concurrent.locks.ReentrantReadWriteLock
import kotlin.concurrent.read

val lock = ReentrantReadWriteLock()
val sharedState = mutableMapOf<String, Int>()

fun readValue(key: String): Int? = lock.read {
    sharedState[key]
}

Source