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.beam.runners.direct;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkState;
  import static org.hamcrest.MatcherAssert.assertThat;
  import static org.hamcrest.Matchers.equalTo;
  import static org.hamcrest.Matchers.is;
  import static org.hamcrest.Matchers.isA;
  import static org.hamcrest.Matchers.not;
  import static org.hamcrest.Matchers.theInstance;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.concurrent.Callable;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.Future;
  import java.util.concurrent.TimeUnit;
  import org.apache.beam.sdk.options.PipelineOptionsFactory;
  import org.apache.beam.sdk.transforms.DoFn;
  import org.apache.beam.sdk.util.UserCodeException;
  import org.hamcrest.Matchers;
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.rules.ExpectedException;
  import org.junit.runner.RunWith;
  import org.junit.runners.JUnit4;
  
  /** Tests for {@link DoFnLifecycleManager}. */
  @RunWith(JUnit4.class)
  public class DoFnLifecycleManagerTest {
    @Rule public ExpectedException thrown = ExpectedException.none();
  
    private TestFn fn = new TestFn();
    private DoFnLifecycleManager mgr = DoFnLifecycleManager.of(fn, PipelineOptionsFactory.create());
  
    @Test
    public void setupOnGet() throws Exception {
      TestFn obtained = (TestFn) mgr.get();
  
      assertThat(obtained, not(theInstance(fn)));
      assertThat(obtained.setupCalled, is(true));
      assertThat(obtained.teardownCalled, is(false));
    }
  
    @Test
    public void getMultipleCallsSingleSetupCall() throws Exception {
      TestFn obtained = (TestFn) mgr.get();
      TestFn secondObtained = (TestFn) mgr.get();
  
      assertThat(obtained, theInstance(secondObtained));
      assertThat(obtained.setupCalled, is(true));
      assertThat(obtained.teardownCalled, is(false));
    }
  
    @Test
    public void getMultipleThreadsDifferentInstances() throws Exception {
      CountDownLatch startSignal = new CountDownLatch(1);
      ExecutorService executor = Executors.newCachedThreadPool();
      List<Future<TestFn>> futures = new ArrayList<>();
      for (int i = 0; i < 10; i++) {
        futures.add(executor.submit(new GetFnCallable(mgr, startSignal)));
      }
      startSignal.countDown();
      List<TestFn> fns = new ArrayList<>();
      for (Future<TestFn> future : futures) {
        fns.add(future.get(1L, TimeUnit.SECONDS));
      }
  
      for (TestFn fn : fns) {
        assertThat(fn.setupCalled, is(true));
        int sameInstances = 0;
        for (TestFn otherFn : fns) {
          if (otherFn == fn) {
            sameInstances++;
          }
        }
        assertThat(sameInstances, equalTo(1));
      }
    }
  
    @Test
    public void teardownOnRemove() throws Exception {
      TestFn obtained = (TestFn) mgr.get();
      mgr.remove();
  
      assertThat(obtained, not(theInstance(fn)));
      assertThat(obtained.setupCalled, is(true));
      assertThat(obtained.teardownCalled, is(true));
  
      assertThat(mgr.get(), not(Matchers.<DoFn<?, ?>>theInstance(obtained)));
    }
  
    @Test
    public void teardownThrowsRemoveThrows() throws Exception {
      TestFn obtained = (TestFn) mgr.get();
      obtained.teardown();
  
      thrown.expect(UserCodeException.class);
      thrown.expectCause(isA(IllegalStateException.class));
      thrown.expectMessage("Cannot call teardown: already torn down");
      mgr.remove();
    }
  
    @Test
    public void teardownAllOnRemoveAll() throws Exception {
      CountDownLatch startSignal = new CountDownLatch(1);
      ExecutorService executor = Executors.newCachedThreadPool();
      List<Future<TestFn>> futures = new ArrayList<>();
      for (int i = 0; i < 10; i++) {
        futures.add(executor.submit(new GetFnCallable(mgr, startSignal)));
      }
      startSignal.countDown();
      List<TestFn> fns = new ArrayList<>();
      for (Future<TestFn> future : futures) {
        fns.add(future.get(1L, TimeUnit.SECONDS));
      }
      mgr.removeAll();
  
      for (TestFn fn : fns) {
        assertThat(fn.setupCalled, is(true));
        assertThat(fn.teardownCalled, is(true));
      }
    }
  
    @Test
    public void removeAndRemoveAllConcurrent() throws Exception {
      CountDownLatch startSignal = new CountDownLatch(1);
      ExecutorService executor = Executors.newCachedThreadPool();
      List<Future<TestFn>> futures = new ArrayList<>();
      for (int i = 0; i < 10; i++) {
        futures.add(executor.submit(new GetFnCallable(mgr, startSignal)));
      }
      startSignal.countDown();
      List<TestFn> fns = new ArrayList<>();
      for (Future<TestFn> future : futures) {
        fns.add(future.get(1L, TimeUnit.SECONDS));
      }
      CountDownLatch removeSignal = new CountDownLatch(1);
      List<Future<Void>> removeFutures = new ArrayList<>();
      for (int i = 0; i < 5; i++) {
        // These will reuse the threads used in the GetFns
        removeFutures.add(executor.submit(new TeardownFnCallable(mgr, removeSignal)));
      }
      removeSignal.countDown();
      assertThat(mgr.removeAll(), Matchers.emptyIterable());
      for (Future<Void> removed : removeFutures) {
        // Should not have thrown an exception.
        removed.get();
      }
  
      for (TestFn fn : fns) {
        assertThat(fn.setupCalled, is(true));
        assertThat(fn.teardownCalled, is(true));
      }
    }
  
    private static class GetFnCallable implements Callable<TestFn> {
      private final DoFnLifecycleManager mgr;
      private final CountDownLatch startSignal;
  
      private GetFnCallable(DoFnLifecycleManager mgr, CountDownLatch startSignal) {
        this.mgr = mgr;
        this.startSignal = startSignal;
      }
  
      @Override
      public TestFn call() throws Exception {
        startSignal.await();
        return (TestFn) mgr.get();
      }
    }
  
    private static class TeardownFnCallable implements Callable<Void> {
      private final DoFnLifecycleManager mgr;
      private final CountDownLatch startSignal;
  
      private TeardownFnCallable(DoFnLifecycleManager mgr, CountDownLatch startSignal) {
        this.mgr = mgr;
        this.startSignal = startSignal;
      }
  
      @Override
      public Void call() throws Exception {
        startSignal.await();
        // Will throw an exception if the TestFn has already been removed from this thread
        mgr.remove();
        return null;
      }
    }
  
    private static class TestFn extends DoFn<Object, Object> {
      boolean setupCalled = false;
      boolean teardownCalled = false;
  
      @Setup
      public void setup() {
        checkState(!setupCalled, "Cannot call setup: already set up");
        checkState(!teardownCalled, "Cannot call setup: already torn down");
  
        setupCalled = true;
      }
  
      @ProcessElement
      public void processElement(ProcessContext c) throws Exception {}
  
      @Teardown
      public void teardown() {
        checkState(setupCalled, "Cannot call teardown: not set up");
        checkState(!teardownCalled, "Cannot call teardown: already torn down");
  
        teardownCalled = true;
      }
    }
  }
  