package com.github.dockerjava.core;

import static org.testng.Assert.assertEquals;

import static org.testng.Assert.assertFalse;

import static org.testng.Assert.assertNotNull;

import java.util.ArrayList;

import java.util.Collections;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

import org.testng.annotations.Test;

import com.github.dockerjava.api.command.DockerCmdExecFactory;

public class DockerClientBuilderTest {

// Amount of instances created in test

private static final int AMOUNT = 100;

@Test

public void testConcurrentClientBuilding() throws Exception {

// we use it to check instance uniqueness

final Set<DockerCmdExecFactory> instances = Collections.synchronizedSet(new HashSet<DockerCmdExecFactory>());

Runnable runnable = new Runnable() {

@Override

public void run() {

DockerCmdExecFactory factory = DockerClientBuilder.getDefaultDockerCmdExecFactory();

// factory created

assertNotNull(factory);

// and is unique

assertFalse(instances.contains(factory));

instances.add(factory);

}

};

parallel(AMOUNT, runnable);

// set contains all required unique instances

assertEquals(instances.size(), AMOUNT);

}

public static void parallel(int threads, final Runnable task) throws Exception {

final ExceptionListener exceptionListener = new ExceptionListener();

Runnable runnable = new Runnable() {

@Override

public void run() {

try {

task.run();

} catch (Throwable e) {

exceptionListener.onException(e);

}

}

};

List<Thread> threadList = new ArrayList<>(threads);

for (int i = 0; i < threads; i++) {

Thread thread = new Thread(runnable);

thread.start();

threadList.add(thread);

}

for (Thread thread : threadList) {

thread.join();

}

Throwable exception = exceptionListener.getException();

if (exception != null) {

throw new RuntimeException(exception);

}

}

private static class ExceptionListener {

private Throwable exception;

private synchronized void onException(Throwable e) {

exception = e;

}

private synchronized Throwable getException() {

return exception;

}

}

}