001/*
002 * Copyright (C) 2008 The Guava Authors
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package com.google.common.testing;
018
019import static com.google.common.base.Preconditions.checkNotNull;
020import static com.google.common.base.Throwables.throwIfUnchecked;
021
022import com.google.common.annotations.GwtCompatible;
023import com.google.common.annotations.VisibleForTesting;
024import com.google.errorprone.annotations.concurrent.GuardedBy;
025import java.util.ArrayDeque;
026import java.util.ArrayList;
027import java.util.Deque;
028import java.util.List;
029import java.util.logging.Level;
030import java.util.logging.Logger;
031import org.jspecify.annotations.NullMarked;
032
033/**
034 * A {@code TearDownStack} contains a stack of {@link TearDown} instances.
035 *
036 * <p>This class is thread-safe.
037 *
038 * @author Kevin Bourrillion
039 * @since 10.0
040 */
041@GwtCompatible
042@NullMarked
043public class TearDownStack implements TearDownAccepter {
044  private static final Logger logger = Logger.getLogger(TearDownStack.class.getName());
045
046  @VisibleForTesting final Object lock = new Object();
047
048  @GuardedBy("lock")
049  final Deque<TearDown> stack = new ArrayDeque<>();
050
051  /*
052   * TODO(cpovirk): Rework the "suppress" terminology in this class for Java's "new" concept of
053   * "suppressed exceptions." At the moment, we use addSuppressed only if suppressThrows is *false*!
054   */
055
056  private final boolean suppressThrows;
057
058  /**
059   * Constructs a new {@code TearDownStack} that does not suppress exceptions throw during teardown.
060   */
061  public TearDownStack() {
062    this.suppressThrows = false;
063  }
064
065  /**
066   * Constructs a new {@code TearDownStack}, specifying whether to suppress exceptions thrown during
067   * teardown.
068   */
069  public TearDownStack(boolean suppressThrows) {
070    this.suppressThrows = suppressThrows;
071  }
072
073  @Override
074  public final void addTearDown(TearDown tearDown) {
075    synchronized (lock) {
076      stack.addFirst(checkNotNull(tearDown));
077    }
078  }
079
080  /** Causes teardown to execute. */
081  public final void runTearDown() {
082    Throwable exception = null;
083    List<TearDown> stackCopy;
084    synchronized (lock) {
085      stackCopy = new ArrayList<>(stack);
086      stack.clear();
087    }
088    for (TearDown tearDown : stackCopy) {
089      try {
090        tearDown.tearDown();
091      } catch (Throwable t) {
092        if (suppressThrows) {
093          logger.log(Level.INFO, "exception thrown during tearDown", t);
094        } else {
095          if (exception == null) {
096            exception = t;
097          } else {
098            exception.addSuppressed(t);
099          }
100        }
101      }
102    }
103    if (exception != null) {
104      throwIfUnchecked(exception);
105      throw new RuntimeException("failure during tearDown", exception);
106    }
107  }
108}