Class FuturesGetChecked

output/java_guava/1.4.16/FuturesGetChecked.java:45–310

Static methods used to implement Futures#getChecked(Future, Class).

@GwtIncompatible
final class FuturesGetChecked {
  @CanIgnoreReturnValue
  static <V, X extends Exception> V getChecked(Future<V> future, Class<X> exceptionClass)
      throws X {
    return getChecked(bestGetCheckedTypeValidator(), future, exceptionClass);
  }

  /**
   * Implementation of {@link Futures#getChecked(Future, Class)}.
   */

  @CanIgnoreReturnValue
  @VisibleForTesting
  static <V, X extends Exception> V getChecked(GetCheckedTypeValidator validator, Future<V> future, Class<X> exceptionClass)
      throws X {
    validator.validateClass(exceptionClass);
    try {
      return future.get();
    } catch (InterruptedException e) {
      currentThread().interrupt();
      throw newWithCause(exceptionClass, e);
    } catch (ExecutionException e) {
      wrapAndThrowExceptionOrError(e.getCause(), exceptionClass);
      throw new AssertionError();
    }
  }

  /**
   * Implementation of {@link Futures#getChecked(Future, Class, long, TimeUnit)}.
   */

  @CanIgnoreReturnValue
  static <V, X extends Exception> V getChecked(Future<V> future, Class<X> exceptionClass, long timeout, TimeUnit unit)
      throws X {
    // TODO(cpovirk): benchmark a version of this method that accepts a GetCheckedTypeValidator
    bestGetCheckedTypeValidator().validateClass(exceptionClass);
    try {
      return future.get(timeout, unit);
    } catch (InterruptedException e) {
      currentThread().interrupt();
      throw newWithCause(exceptionClass, e);
    } catch (TimeoutException e) {
      throw newWithCause(exceptionClass, e);
    } catch (ExecutionException e) {
      wrapAndThrowExceptionOrError(e.getCause(), exceptionClass);
      throw new AssertionError();
    }
  }

  @VisibleForTesting
  interface GetCheckedTypeValidator {

    void validateClass(Class<? extends Exception> exceptionClass);
  }

  private static GetCheckedTypeValidator bestGetCheckedTypeValidator() {
    return GetCheckedTypeValidatorHolder.BEST_VALIDATOR;