Class LazyStorage

api/src/context/java/io/grpc/Context.java:113–140

  // they don't depend on storage, like key() and currentContextExecutor(). It also makes it easier
  // to handle exceptions.
  private static final class LazyStorage {
    static final Storage storage;

    static {
      AtomicReference<Throwable> deferredStorageFailure = new AtomicReference<>();
      storage = createStorage(deferredStorageFailure);
      Throwable failure = deferredStorageFailure.get();
      // Logging must happen after storage has been set, as loggers may use Context.
      if (failure != null) {
        log.log(Level.FINE, "Storage override doesn't exist. Using default", failure);
      }
    }

    private static Storage createStorage(
        AtomicReference<? super ClassNotFoundException> deferredStorageFailure) {
      try {
        Class<?> clazz = Class.forName("io.grpc.override.ContextStorageOverride");
        // The override's constructor is prohibited from triggering any code that can loop back to
        // Context
        return clazz.asSubclass(Storage.class).getConstructor().newInstance();
      } catch (ClassNotFoundException e) {
        deferredStorageFailure.set(e);
        return new ThreadLocalContextStorage();
      } catch (Exception e) {
        throw new RuntimeException("Storage override failed to initialize", e);
      }
    }
  }

  /**
   * Create a {@link Key} with the given debug name.