How to use

blockingRun

method

in

com.linkedin.parseq.Engine

@Override
public void runTask(Engine engine, Task<?> t) {
 engine.blockingRun(t);
}

/**
 * Runs the given task. Task passed in as a parameter becomes a root on a new Plan.
 * All tasks created and started as a consequence of a root task will belong to that plan and will share a Trace.
 * <p>
 * This method blocks until Engine has a capacity to run the task. Engine's capacity is
 * specified by a {@value #MAX_CONCURRENT_PLANS} configuration property. Use
 * {@link EngineBuilder#setEngineProperty(String, Object)} to set this property.
 * For the sake of backwards compatibility default value for a {@value #MAX_CONCURRENT_PLANS} is
 * {@value #DEFUALT_MAX_CONCURRENT_PLANS} which essentially means "unbounded capacity".
 *
 * @param task the task to run
 */
public void blockingRun(final Task<?> task) {
 blockingRun(task, defaultPlanClass(task));
}

@Test
public void testBlockingRunWithinCapacity() throws InterruptedException {
 final AtomicInteger counter = new AtomicInteger(0);
 Task<?>[] tasks = new Task<?>[10];
 for (int i = 0; i < 10; i++) {
  tasks[i] = Task.action(counter::incrementAndGet);
 }
 for (int i = 0; i < 10; i++) {
  _engine.blockingRun(tasks[i], (i % 2 == 0) ? "evenPlan" : "oddPlan");
 }
 assertTrue(awaitAll(tasks));
 assertEquals(10, counter.get());
}

@Test
public void testBlockingRunOverCapacity() throws InterruptedException {
 final CountDownLatch latch = new CountDownLatch(1);
 Task<?>[] tasks = new Task<?>[10];
 for (int i = 0; i < 10; i++) {
  tasks[i] = Task.action(latch::await);
 }
 //within capacity
 for (int i = 0; i < 10; i++) {
  _engine.blockingRun(tasks[i], (i % 2 == 0) ? "evenPlan" : "oddPlan");
 }
 final CountDownLatch blockedTaskLatch = new CountDownLatch(1);
 final CountDownLatch blockedThreadLatch = new CountDownLatch(1);
 new Thread(() -> {
  blockedThreadLatch.countDown();
  _engine.blockingRun(Task.action(() -> { blockedTaskLatch.countDown(); }), "oddPlan");
 }).start();
 //first wait for a background thread to reach _engine.run()
 assertTrue(blockedThreadLatch.await(5, TimeUnit.SECONDS));
 //sleep for 200ms to make sure background thread executed _engine.run()
 Thread.sleep(200);
 //verify background tasks didn't run
 assertEquals(1L, blockedTaskLatch.getCount());
 //release tasks
 latch.countDown();
 //background thread should be unblocked and background task should eventually run
 assertTrue(blockedTaskLatch.await(5, TimeUnit.SECONDS));
}

@Test
public void testBlockingRunOverCapacity() throws InterruptedException {
 final CountDownLatch latch = new CountDownLatch(1);
 Task<?>[] tasks = new Task<?>[10];
 for (int i = 0; i < 10; i++) {
  tasks[i] = Task.action(latch::await);
 }
 //within capacity
 for (int i = 0; i < 10; i++) {
  _engine.blockingRun(tasks[i]);
 }
 final CountDownLatch blockedTaskLatch = new CountDownLatch(1);
 final CountDownLatch blockedThreadLatch = new CountDownLatch(1);
 new Thread(() -> {
  blockedThreadLatch.countDown();
  _engine.blockingRun(Task.action(() -> { blockedTaskLatch.countDown(); }));
 }).start();
 //first wait for a background thread to reach _engine.run()
 assertTrue(blockedThreadLatch.await(5, TimeUnit.SECONDS));
 //sleep for 200ms to make sure background thread executed _engine.run()
 Thread.sleep(200);
 //verify background tasks didn't run
 assertEquals(1L, blockedTaskLatch.getCount());
 //release tasks
 latch.countDown();
 //background thread should be unblocked and background task should eventually run
 assertTrue(blockedTaskLatch.await(5, TimeUnit.SECONDS));
}

@Test
public void testBlockingRunWithinCapacity() throws InterruptedException {
 final AtomicInteger counter = new AtomicInteger(0);
 Task<?>[] tasks = new Task<?>[10];
 for (int i = 0; i < 10; i++) {
  tasks[i] = Task.action(counter::incrementAndGet);
 }
 for (int i = 0; i < 10; i++) {
  _engine.blockingRun(tasks[i]);
 }
 assertTrue(awaitAll(tasks));
 assertEquals(10, counter.get());
}

/**
 * Runs the given task. Task passed in as a parameter becomes a root on a new Plan.
 * All tasks created and started as a consequence of a root task will belong to that plan and will share a Trace.
 * <p>
 * This method blocks until Engine has a capacity to run the task. Engine's capacity is
 * specified by a {@value #MAX_CONCURRENT_PLANS} configuration property. Use
 * {@link EngineBuilder#setEngineProperty(String, Object)} to set this property.
 * For the sake of backwards compatibility default value for a {@value #MAX_CONCURRENT_PLANS} is
 * {@value #DEFUALT_MAX_CONCURRENT_PLANS} which essentially means "unbounded capacity".
 *
 * @param task the task to run
 */
public void blockingRun(final Task<?> task) {
 blockingRun(task, defaultPlanClass(task));
}