Class SuppressingSuppressor

output/java_guava/1.4.17/Closer.java:276–307

Suppresses exceptions by adding them to the exception that will be thrown using JDK7's addSuppressed(Throwable) mechanism.

   */

  @VisibleForTesting
  static final class SuppressingSuppressor implements Suppressor {
    static final SuppressingSuppressor INSTANCE = new SuppressingSuppressor();

    static boolean isAvailable() {
      return addSuppressed != null;
           }


    static final Method addSuppressed = getAddSuppressed();
    private static Method getAddSuppressed() {
      try {
        return Throwable.class.getMethod("addSuppressed", Throwable.class);
      } catch (Throwable e) {
        return null;
      }
    }

    @Override
    public void suppress(Closeable closeable, Throwable thrown, Throwable suppressed) {
      // ensure no exceptions from addSuppressed
      if (thrown == suppressed) {
        return;
      }
      try {
        addSuppressed.invoke(thrown, suppressed);
      } catch (Throwable e) {
        // if, somehow, IllegalAccessException or another exception is thrown, fall back to logging
        LoggingSuppressor.INSTANCE.suppress(closeable, thrown, suppressed);
      }
    }
  }
}