content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   *
   *    http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.kafka.connect.util;
  
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  import java.util.concurrent.CancellationException;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.ExecutionException;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.TimeoutException;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.concurrent.atomic.AtomicReference;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  import static org.junit.jupiter.api.Assertions.fail;
  
  public class ConvertingFutureCallbackTest {
  
      private ExecutorService executor;
  
      @BeforeEach
      public void setup() {
          executor = Executors.newSingleThreadExecutor();
      }
    
      @Test
      public void shouldConvertBeforeGetOnSuccessfulCompletion() throws Exception {
          final Object expectedConversion = new Object();
          TestConvertingFutureCallback testCallback = new TestConvertingFutureCallback();
          testCallback.onCompletion(null, expectedConversion);
          assertEquals(1, testCallback.numberOfConversions());
          assertEquals(expectedConversion, testCallback.get());
      }
  
      @Test
      public void shouldConvertOnlyOnceBeforeGetOnSuccessfulCompletion() throws Exception {
          final Object expectedConversion = new Object();
          TestConvertingFutureCallback testCallback = new TestConvertingFutureCallback();
          testCallback.onCompletion(null, expectedConversion);
          testCallback.onCompletion(null, 69);
          testCallback.cancel(true);
          testCallback.onCompletion(new RuntimeException(), null);
          assertEquals(1, testCallback.numberOfConversions());
          assertEquals(expectedConversion, testCallback.get());
      }
  
      @Test
      public void shouldNotConvertBeforeGetOnFailedCompletion() throws Exception {
          final Throwable expectedError = new Throwable();
          TestConvertingFutureCallback testCallback = new TestConvertingFutureCallback();
          testCallback.onCompletion(expectedError, null);
          assertEquals(0, testCallback.numberOfConversions());
          try {
              testCallback.get();
              fail("Expected ExecutionException");
          } catch (ExecutionException e) {
              assertEquals(expectedError, e.getCause());
          }
      }
  
      @Test
      public void shouldRecordOnlyFirstErrorBeforeGetOnFailedCompletion() throws Exception {
          final Throwable expectedError = new Throwable();
          TestConvertingFutureCallback testCallback = new TestConvertingFutureCallback();
          testCallback.onCompletion(expectedError, null);
          testCallback.onCompletion(new RuntimeException(), null);
          testCallback.cancel(true);
          testCallback.onCompletion(null, "420");
          assertEquals(0, testCallback.numberOfConversions());
          try {
              testCallback.get();
              fail("Expected ExecutionException");
          } catch (ExecutionException e) {
              assertEquals(expectedError, e.getCause());
          }
      }
    
      @Test
      public void shouldCancelBeforeGetIfMayCancelWhileRunning() {
          TestConvertingFutureCallback testCallback = new TestConvertingFutureCallback();
          assertTrue(testCallback.cancel(true));
          assertThrows(CancellationException.class, testCallback::get);
      }
  
      @Test
      public void shouldBlockUntilSuccessfulCompletion() throws Exception {
          AtomicReference<Exception> testThreadException = new AtomicReference<>();
          TestConvertingFutureCallback testCallback = new TestConvertingFutureCallback();
          final Object expectedConversion = new Object();
          executor.submit(() -> {
              try {
                  testCallback.waitForGet();
                  testCallback.onCompletion(null, expectedConversion);
              } catch (Exception e) {
                  testThreadException.compareAndSet(null, e);
              }
          });
          assertFalse(testCallback.isDone());
          assertEquals(expectedConversion, testCallback.get());
          assertEquals(1, testCallback.numberOfConversions());
          assertTrue(testCallback.isDone());
          if (testThreadException.get() != null) {
              throw testThreadException.get();
          }
      }
  
      @Test
      public void shouldBlockUntilFailedCompletion() throws Exception {
          AtomicReference<Exception> testThreadException = new AtomicReference<>();
          TestConvertingFutureCallback testCallback = new TestConvertingFutureCallback();
          final Throwable expectedError = new Throwable();
          executor.submit(() -> {
              try {
                  testCallback.waitForGet();
                  testCallback.onCompletion(expectedError, null);
              } catch (Exception e) {
                  testThreadException.compareAndSet(null, e);
              }
          });
          assertFalse(testCallback.isDone());
          try {
              testCallback.get();
              fail("Expected ExecutionException");
          } catch (ExecutionException e) {
              assertEquals(expectedError, e.getCause());
          }
          assertEquals(0, testCallback.numberOfConversions());
          assertTrue(testCallback.isDone());
          if (testThreadException.get() != null) {
              throw testThreadException.get();
          }
      }
  
      @Test
      public void shouldBlockUntilCancellation() {
          AtomicReference<Exception> testThreadException = new AtomicReference<>();
          TestConvertingFutureCallback testCallback = new TestConvertingFutureCallback();
          executor.submit(() -> {
              try {
                  testCallback.waitForGet();
                  testCallback.cancel(true);
              } catch (Exception e) {
                  testThreadException.compareAndSet(null, e);
              }
          });
          assertFalse(testCallback.isDone());
          assertThrows(CancellationException.class, testCallback::get);
      }
  
      @Test
      public void shouldNotCancelIfMayNotCancelWhileRunning() throws Exception {
          AtomicReference<Exception> testThreadException = new AtomicReference<>();
          TestConvertingFutureCallback testCallback = new TestConvertingFutureCallback();
          final Object expectedConversion = new Object();
          executor.submit(() -> {
              try {
                  testCallback.waitForCancel();
                  testCallback.onCompletion(null, expectedConversion);
              } catch (Exception e) {
                  testThreadException.compareAndSet(null, e);
              }
          });
          assertFalse(testCallback.isCancelled());
          assertFalse(testCallback.isDone());
          testCallback.cancel(false);
          assertFalse(testCallback.isCancelled());
          assertTrue(testCallback.isDone());
          assertEquals(expectedConversion, testCallback.get());
          assertEquals(1, testCallback.numberOfConversions());
          if (testThreadException.get() != null) assertThrows(CancellationException.class, testThreadException::get);
      }
    
      protected static class TestConvertingFutureCallback extends ConvertingFutureCallback<Object, Object> {
          private final AtomicInteger numberOfConversions = new AtomicInteger();
          private final CountDownLatch getInvoked = new CountDownLatch(1);
          private final CountDownLatch cancelInvoked = new CountDownLatch(1);
      
          public int numberOfConversions() {
              return numberOfConversions.get();
          }
  
          public void waitForGet() throws InterruptedException {
              getInvoked.await();
          }
  
          public void waitForCancel() throws InterruptedException {
              cancelInvoked.await();
          }
      
          @Override
          public Object convert(Object result) {
              numberOfConversions.incrementAndGet();
              return result;
          }
  
          @Override
          public Object get() throws InterruptedException, ExecutionException {
              getInvoked.countDown();
              return super.get();
          }
  
          @Override
          public Object get(
              long duration,
              TimeUnit unit
          ) throws InterruptedException, ExecutionException, TimeoutException {
              getInvoked.countDown();
              return super.get(duration, unit);
          }
  
          @Override
          public boolean cancel(boolean mayInterruptIfRunning) {
              cancelInvoked.countDown();
              return super.cancel(mayInterruptIfRunning);
          }
      }
  }
  