• CoroutineContext serves as a vital interface and a cornerstone of coroutines.

• A coroutine launches with a context and remains tied to it until the completion or cancellation of its job.

• It represents an indexed set of Element instances.

  • An indexed set combines the characteristics of a set and a map.

  • Each element in this set possesses a unique key.

  • Element implements the CoroutineContext interface.

    • An element within the coroutine context is a singleton context on its own.

• By default, any coroutine builder or scope function utilizes an empty coroutine context known as EmptyCoroutineContext.

• It is generally discouraged to access the coroutineContext property of a CoroutineScope in regular code

  • except when accessing the Job instance for advanced purposes.

Code blocks

• CoroutineContext interface holds these given below three blocks of code.

public interface CoroutineContext {
    public operator fun <E : Element> get(key: Key<E>): E?
    public operator fun plus(context: CoroutineContext): CoroutineContext {}
    public fun minusKey(key: Key<*>): CoroutineContext
    public fun <R> fold(initial: R, operation: (R, Element) -> R): R
}

public interface Key<E : Element>

public interface Element : CoroutineContext {
    // A key of this coroutine context element.
    public val key: Key<*>

    public override operator fun <E : Element> get(key: Key<E>): E? {}
    public override fun minusKey(key: Key<*>): CoroutineContext = {}
    public override fun <R> fold(initial: R, operation: (R, Element) -> R): R {}
}

• A few examples of CoroutineContext's Element are:

  • EmptyCoroutineContext, CombinedContext

  • AbstractCoroutineContextElement

  • EventLoop, BlockingEventLoop

  • Dispatcher, DefaultScheduler

Example

@OptIn(ExperimentalStdlibApi::class)
suspend fun main() {

    val coroutineName = CoroutineName("Name: EmptyCoroutineContext") + EmptyCoroutineContext
    val job = GlobalScope.launch(coroutineName) {
        val dispatcher = coroutineContext[CoroutineDispatcher]
        val name = coroutineContext[CoroutineName]?.name
        println("Coroutine Context details: $name , Dispatcher: $dispatcher")
    }
    job.join()
}

Happy coding... 😊