Kotlin coroutine's demo

gistfile1.txt

package com.example.demo

import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import kotlinx.coroutines.experimental.*

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
//        coroutineDemo()
//        runBlockingDemo()
//        doWorksInSeries()
//        doWorksInParallel()
    }

    //  #2
    fun runBlockingDemo() {
        runBlocking {
            delay(2000)
            println("Kotlin inside coroutines")
        }
    }
    // The output will be
    // Kotlin inside coroutines

    //  #1
    fun coroutineDemo() {
        println("Kotlin Start")
        launch(CommonPool) {
            delay(2000)
            println("Kotlin Inside")
        }
        println("Kotlin End")
    }
    // The output will be
    // Kotlin Start
    // Kotlin End
    // Kotlin Inside

    suspend fun doWorkFor1Seconds(): String {
        delay(1000)
        return "doWorkFor1Seconds"
    }

    suspend fun doWorkFor2Seconds(): String {
        delay(2000)
        return "doWorkFor2Seconds"
    }

    //  #3
    // Serial execution
    fun doWorksInSeries() {
        launch(CommonPool) {
            val one = doWorkFor1Seconds()
            val two = doWorkFor2Seconds()
            println("Kotlin One : " + one)
            println("Kotlin Two : " + two)
        }
    }
    // The output is
    // Kotlin One : doWorkFor1Seconds
    // Kotlin Two : doWorkFor2Seconds

    //  #4
    // Parallel execution
    private fun doWorksInParallel() {
        val one = async(CommonPool) {
            doWorkFor1Seconds()
        }
        val two = async(CommonPool) {
            doWorkFor2Seconds()
        }
        launch(CommonPool) {
            val combined = one.await() + "_" + two.await()
            println("Kotlin Combined : " + combined)
        }
    }
    // The output is
    // Kotlin Combined : doWorkFor1Seconds_doWorkFor2Seconds
}