Code for Once

Once.kt

import java.util.concurrent.atomic.AtomicInteger

/**
 * Construct that helps to restrict the code execution frequency to 1. It will not allow the snippet passed through the close to be executed more than once.
 * The first client to execute run() will execute this and other calls to run() will not be respected till reset is called.
 */

class Once {
    private val mCounter = AtomicInteger(0)

    fun run(code: Closure) {
        if (mCounter.compareAndSet(0, 1)) {
            code.invoke()
        }
    }

    fun isExecuted(): Boolean {
        return mCounter.get() == 1
    }

    fun reset() = mCounter.set(0)
}

// Represents the closure. Not using default kotlin lambda here to avoid ugly looking <Function0> class generated for Java-Kotlin Compat
interface Closure {
    fun invoke()
}