A couple of trivial examples with futures

Author: elizarov

kotlinx-coroutines-jdk8/src/test/kotlin/examples/simple-example-1.kt

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+package examples
+
+import kotlinx.coroutines.experimental.future.await
+import kotlinx.coroutines.experimental.runBlocking
+import java.util.concurrent.CompletableFuture
+
+fun main(args: Array<String>) {
+    // Let's assume that we have a future coming from some 3rd party API
+    val future: CompletableFuture<Int> = CompletableFuture.supplyAsync {
+        Thread.sleep(1000L) // imitate some long-running computation, actually
+        42
+    }
+    // now let's launch a coroutine and await for this future inside it
+    runBlocking {
+        println("We can do something else, while we are waiting for future...")
+        println("We've got ${future.await()} from the future!")
+    }
+}

kotlinx-coroutines-jdk8/src/test/kotlin/examples/simple-example-2.kt

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+package examples
+
+import kotlinx.coroutines.experimental.delay
+import kotlinx.coroutines.experimental.future.future
+import java.util.concurrent.CompletableFuture
+import java.util.concurrent.TimeUnit
+
+// this function returns a CompletableFuture using Kotlin coroutines
+fun supplyTheAnswerAsync(): CompletableFuture<Int> = future {
+    println("We might be doing some asynchronous IO here or something else...")
+    delay(1, TimeUnit.SECONDS) // just do a non-blocking delay
+    42 // The answer!
+}
+
+fun main(args: Array<String>) {
+    // We can use `supplyTheAnswerAsync` just like any other future-supplier function
+    val future = supplyTheAnswerAsync()
+    println("The answer is ${future.get()}")
+}