Examples of Quasar in Kotlin (#7045)

This commit is contained in:
Graham Cox 2019-05-31 09:09:26 +01:00 committed by Grzegorz Piwowarek
parent 823cd0b9b9
commit 76370b794f
7 changed files with 477 additions and 0 deletions

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kotlin-quasar/pom.xml Normal file
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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.baeldung</groupId>
<artifactId>kotlin-quasar</artifactId>
<version>1.0.0-SNAPSHOT</version>
<name>kotlin-quasar</name>
<packaging>jar</packaging>
<dependencies>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-stdlib-jdk8</artifactId>
<version>${kotlin.version}</version>
</dependency>
<dependency>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-test</artifactId>
<version>${kotlin.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>co.paralleluniverse</groupId>
<artifactId>quasar-core</artifactId>
<version>${quasar.version}</version>
</dependency>
<dependency>
<groupId>co.paralleluniverse</groupId>
<artifactId>quasar-actors</artifactId>
<version>${quasar.version}</version>
</dependency>
<dependency>
<groupId>co.paralleluniverse</groupId>
<artifactId>quasar-reactive-streams</artifactId>
<version>${quasar.version}</version>
</dependency>
<dependency>
<groupId>co.paralleluniverse</groupId>
<artifactId>quasar-kotlin</artifactId>
<version>${quasar.version}</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
</dependency>
</dependencies>
<build>
<sourceDirectory>src/main/kotlin</sourceDirectory>
<testSourceDirectory>src/test/kotlin</testSourceDirectory>
<plugins>
<plugin>
<groupId>org.jetbrains.kotlin</groupId>
<artifactId>kotlin-maven-plugin</artifactId>
<version>${kotlin.version}</version>
<executions>
<execution>
<id>compile</id>
<phase>compile</phase>
<goals>
<goal>compile</goal>
</goals>
</execution>
<execution>
<id>test-compile</id>
<phase>test-compile</phase>
<goals>
<goal>test-compile</goal>
</goals>
</execution>
</executions>
<configuration>
<jvmTarget>1.8</jvmTarget>
</configuration>
</plugin>
<plugin>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.1.1</version>
<executions>
<execution>
<id>getClasspathFilenames</id>
<goals>
<goal>properties</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.22.1</version>
<configuration>
<argLine>-Dco.paralleluniverse.fibers.verifyInstrumentation=true</argLine>
<argLine>-javaagent:${co.paralleluniverse:quasar-core:jar}</argLine>
</configuration>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>1.3.2</version>
<configuration>
<workingDirectory>target/classes</workingDirectory>
<executable>echo</executable>
<arguments>
<argument>-javaagent:${co.paralleluniverse:quasar-core:jar}</argument>
<argument>-classpath</argument> <classpath/>
<argument>com.baeldung.quasar.QuasarHelloWorldKt</argument>
</arguments>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<quasar.version>0.8.0</quasar.version>
<kotlin.version>1.3.31</kotlin.version>
</properties>
</project>

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package com.baeldung.quasar
import co.paralleluniverse.fibers.Fiber
import co.paralleluniverse.strands.SuspendableRunnable
/**
* Entrypoint into the application
*/
fun main(args: Array<String>) {
class Runnable : SuspendableRunnable {
override fun run() {
println("Hello")
}
}
val result = Fiber<Void>(Runnable()).start()
result.join()
println("World")
}

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package com.baeldung.quasar
import co.paralleluniverse.fibers.Suspendable
import co.paralleluniverse.kotlin.fiber
import co.paralleluniverse.strands.channels.Channels
import co.paralleluniverse.strands.channels.Selector
import com.google.common.base.Function
import org.junit.Test
class ChannelsTest {
@Test
fun createChannel() {
Channels.newChannel<String>(0, // The size of the channel buffer
Channels.OverflowPolicy.BLOCK, // The policy for when the buffer is full
true, // Whether we should optimize for a single message producer
true) // Whether we should optimize for a single message consumer
}
@Test
fun blockOnMessage() {
val channel = Channels.newChannel<String>(0, Channels.OverflowPolicy.BLOCK, true, true)
fiber @Suspendable {
while (!channel.isClosed) {
val message = channel.receive()
println("Received: $message")
}
println("Stopped receiving messages")
}
channel.send("Hello")
channel.send("World")
channel.close()
}
@Test
fun selectReceiveChannels() {
val channel1 = Channels.newChannel<String>(0, Channels.OverflowPolicy.BLOCK, true, true)
val channel2 = Channels.newChannel<String>(0, Channels.OverflowPolicy.BLOCK, true, true)
fiber @Suspendable {
while (!channel1.isClosed && !channel2.isClosed) {
val received = Selector.select(Selector.receive(channel1), Selector.receive(channel2))
println("Received: $received")
}
}
fiber @Suspendable {
for (i in 0..10) {
channel1.send("Channel 1: $i")
}
}
fiber @Suspendable {
for (i in 0..10) {
channel2.send("Channel 2: $i")
}
}
}
@Test
fun selectSendChannels() {
val channel1 = Channels.newChannel<String>(0, Channels.OverflowPolicy.BLOCK, true, true)
val channel2 = Channels.newChannel<String>(0, Channels.OverflowPolicy.BLOCK, true, true)
fiber @Suspendable {
for (i in 0..10) {
Selector.select(
Selector.send(channel1, "Channel 1: $i"),
Selector.send(channel2, "Channel 2: $i")
)
}
}
fiber @Suspendable {
while (!channel1.isClosed) {
val msg = channel1.receive()
println("Read: $msg")
}
}
fiber @Suspendable {
while (!channel2.isClosed) {
val msg = channel2.receive()
println("Read: $msg")
}
}
}
@Test
fun tickerChannel() {
val channel = Channels.newChannel<String>(3, Channels.OverflowPolicy.DISPLACE)
for (i in 0..10) {
val tickerConsumer = Channels.newTickerConsumerFor(channel)
fiber @Suspendable {
while (!tickerConsumer.isClosed) {
val message = tickerConsumer.receive()
println("Received on $i: $message")
}
println("Stopped receiving messages on $i")
}
}
for (i in 0..50) {
channel.send("Message $i")
}
channel.close()
}
@Test
fun transformOnSend() {
val channel = Channels.newChannel<String>(0, Channels.OverflowPolicy.BLOCK, true, true)
fiber @Suspendable {
while (!channel.isClosed) {
val message = channel.receive()
println("Received: $message")
}
println("Stopped receiving messages")
}
val transformOnSend = Channels.mapSend(channel, Function<String, String> { msg: String? -> msg?.toUpperCase() })
transformOnSend.send("Hello")
transformOnSend.send("World")
channel.close()
}
@Test
fun transformOnReceive() {
val channel = Channels.newChannel<String>(0, Channels.OverflowPolicy.BLOCK, true, true)
val transformOnReceive = Channels.map(channel, Function<String, String> { msg: String? -> msg?.reversed() })
fiber @Suspendable {
while (!transformOnReceive.isClosed) {
val message = transformOnReceive.receive()
println("Received: $message")
}
println("Stopped receiving messages")
}
channel.send("Hello")
channel.send("World")
channel.close()
}
}

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package com.baeldung.quasar
import co.paralleluniverse.strands.dataflow.Val
import co.paralleluniverse.strands.dataflow.Var
import org.junit.Assert
import org.junit.Test
import java.util.concurrent.TimeUnit
class DataflowTest {
@Test
fun testValVar() {
val a = Var<Int>()
val b = Val<Int>()
val c = Var<Int> { a.get() + b.get() }
val d = Var<Int> { a.get() * b.get() }
// (a*b) - (a+b)
val initialResult = Val<Int> { d.get() - c.get() }
val currentResult = Var<Int> { d.get() - c.get() }
a.set(2)
b.set(4)
Assert.assertEquals(2, initialResult.get())
Assert.assertEquals(2, currentResult.get())
a.set(3)
TimeUnit.SECONDS.sleep(1)
Assert.assertEquals(2, initialResult.get())
Assert.assertEquals(5, currentResult.get())
}
}

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package com.baeldung.quasar
import co.paralleluniverse.fibers.Fiber
import co.paralleluniverse.fibers.FiberAsync
import co.paralleluniverse.fibers.Suspendable
import co.paralleluniverse.kotlin.fiber
import co.paralleluniverse.strands.Strand
import org.junit.Assert
import org.junit.Test
import java.math.BigDecimal
import java.util.concurrent.TimeUnit
interface PiCallback {
fun success(result: BigDecimal)
fun failure(error: Exception)
}
fun computePi(callback: PiCallback) {
println("Starting calculations")
TimeUnit.SECONDS.sleep(2)
println("Finished calculations")
callback.success(BigDecimal("3.14"))
}
class PiAsync : PiCallback, FiberAsync<BigDecimal, Exception>() {
override fun success(result: BigDecimal) {
asyncCompleted(result)
}
override fun failure(error: Exception) {
asyncFailed(error)
}
override fun requestAsync() {
computePi(this)
}
}
class PiAsyncTest {
@Test
fun testPi() {
val result = fiber @Suspendable {
val pi = PiAsync()
println("Waiting to get PI on: " + Fiber.currentFiber().name)
val result = pi.run()
println("Got PI")
result
}.get()
Assert.assertEquals(BigDecimal("3.14"), result)
}
}

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package com.baeldung.quasar
import co.paralleluniverse.fibers.Fiber
import co.paralleluniverse.fibers.Suspendable
import co.paralleluniverse.kotlin.fiber
import co.paralleluniverse.strands.SuspendableCallable
import org.junit.Assert
import org.junit.Test
import java.util.concurrent.TimeUnit
class SuspendableCallableTest {
@Test
fun createFiber() {
class Callable : SuspendableCallable<String> {
override fun run(): String {
println("Inside Fiber")
return "Hello"
}
}
val result = Fiber<String>(Callable()).start()
Assert.assertEquals("Hello", result.get())
}
@Test
fun createFiberLambda() {
val lambda: (() -> String) = {
println("Inside Fiber Lambda")
"Hello"
}
val result = Fiber<String>(lambda)
result.start()
Assert.assertEquals("Hello", result.get())
}
@Test
fun createFiberDsl() {
val result = fiber @Suspendable {
TimeUnit.SECONDS.sleep(5)
println("Inside Fiber DSL")
"Hello"
}
Assert.assertEquals("Hello", result.get())
}
}

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package com.baeldung.quasar
import co.paralleluniverse.fibers.Fiber
import co.paralleluniverse.fibers.Suspendable
import co.paralleluniverse.kotlin.fiber
import co.paralleluniverse.strands.SuspendableRunnable
import org.junit.Test
import java.util.concurrent.TimeUnit
import java.util.concurrent.TimeoutException
class SuspensableRunnableTest {
@Test
fun createFiber() {
class Runnable : SuspendableRunnable {
override fun run() {
println("Inside Fiber")
}
}
val result = Fiber<Void>(Runnable()).start()
result.join()
}
@Test
fun createFiberLambda() {
val result = Fiber<Void> {
println("Inside Fiber Lambda")
}
result.start()
result.join()
}
@Test
fun createFiberDsl() {
fiber @Suspendable {
println("Inside Fiber DSL")
}.join()
}
@Test(expected = TimeoutException::class)
fun fiberTimeout() {
fiber @Suspendable {
TimeUnit.SECONDS.sleep(5)
println("Inside Fiber DSL")
}.join(2, TimeUnit.SECONDS)
}
}