/*
 * Copyright (C) 2011 The Guava Authors
 *
 * 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.common.util.concurrent;

import com.google.common.annotations.GwtCompatible;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * {@link Error} variant of {@link java.util.concurrent.ExecutionException}. As with {@code
 * ExecutionException}, the error's {@linkplain #getCause() cause} comes from a failed task,
 * possibly run in another thread. That cause should itself be an {@code Error}; if not, use {@code
 * ExecutionException} or {@link UncheckedExecutionException}. This allows the client code to
 * continue to distinguish between exceptions and errors, even when they come from other threads.
 *
 * @author Chris Povirk
 * @since 10.0
 */
@GwtCompatible
public class ExecutionError extends Error {
  /*
   * Ideally, this class would have exposed only constructors that require a non-null cause. See
   * https://github.com/jspecify/jspecify-reference-checker/blob/61aafa4ae52594830cfc2d61c8b113009dbdb045/src/main/java/com/google/jspecify/nullness/NullSpecTransfer.java#L789
   * and https://github.com/jspecify/jspecify/issues/490.
   *
   * (That would also have ensured that its cause was always an Error, rather than possibly another
   * kind of Throwable that was later passed to initCause. Then we could have declared the override
   * `public final Error getCause()`.)
   */

  /**
   * Creates a new instance with {@code null} as its detail message and no cause.
   *
   * @deprecated Prefer {@linkplain ExecutionError(Error)} a constructor that accepts a cause: Users
   *     of this class typically expect for instances to have a non-null cause. At the moment, you
   *     can <i>usually</i> still preserve behavior by passing an explicit {@code null} cause. Note,
   *     however, that passing an explicit {@code null} cause prevents anyone from calling {@link
   *     #initCause} later, so it is not quite equivalent to using a constructor that omits the
   *     cause.
   */
  @Deprecated
  protected ExecutionError() {}

  /**
   * Creates a new instance with the given detail message and no cause.
   *
   * @deprecated Prefer {@linkplain ExecutionError(String, Error)} a constructor that accepts a
   *     cause: Users of this class typically expect for instances to have a non-null cause. At the
   *     moment, you can <i>usually</i> still preserve behavior by passing an explicit {@code null}
   *     cause. Note, however, that passing an explicit {@code null} cause prevents anyone from
   *     calling {@link #initCause} later, so it is not quite equivalent to using a constructor that
   *     omits the cause.
   */
  @Deprecated
  protected ExecutionError(@Nullable String message) {
    super(message);
  }

  /**
   * Creates a new instance with the given detail message and cause. Prefer to provide a
   * non-nullable {@code cause}, as many users expect to find one.
   */
  public ExecutionError(@Nullable String message, @Nullable Error cause) {
    super(message, cause);
  }

  /**
   * Creates a new instance with {@code null} as its detail message and the given cause. Prefer to
   * provide a non-nullable {@code cause}, as many users expect to find one.
   */
  public ExecutionError(@Nullable Error cause) {
    super(cause);
  }

  private static final long serialVersionUID = 0;
}