src/main/java/com/google/devtools/build/lib/concurrent/ThrowableRecordingRunnableWrapper.java


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// Copyright 2014 Google Inc. All rights reserved.
//
// Licensed 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 com.google.devtools.build.lib.concurrent;

import com.google.common.base.Preconditions;

import java.util.concurrent.atomic.AtomicReference;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.annotation.Nullable;

/**
 * A class that wraps Runnables and records the first Throwable thrown by the wrapped Runnables
 * when they are run.
 */
public class ThrowableRecordingRunnableWrapper {

  private final String name;
  private AtomicReference<Throwable> errorRef = new AtomicReference<>();

  private static final Logger LOG =
      Logger.getLogger(ThrowableRecordingRunnableWrapper.class.getName());

  public ThrowableRecordingRunnableWrapper(String name) {
    this.name = Preconditions.checkNotNull(name);
  }

  @Nullable
  public Throwable getFirstThrownError() {
    return errorRef.get();
  }

  public Runnable wrap(final Runnable runnable) {
    return new Runnable() {
      @Override
      public void run() {
        try {
          runnable.run();
        } catch (Throwable error) {
          errorRef.compareAndSet(null, error);
          LOG.log(Level.SEVERE, "Error thrown by runnable in " + name, error);
        }
      }
    };
  }
}