checkNotNull(key);
    V value = getIfCached(key);
    if (value != null) {
      return value;
    }

    value = getWithoutCaching(key);
    if (value != null) {
      addToCache((K) key, value);
    }
    return value;
  }

  // Internal methods (package-visible, but treat as only subclass-visible)

  @Override
  @Nullable V getIfCached(@Nullable Object key) {

    clearCache();
    return backingMap.remove(key);
  }

  final void clear() {
    clearCache();
    backingMap.clear();
  }

  @Nullable V get(Object key) {
    checkNotNull(key);
    V value = getIfCached(key);
    // TODO(b/192579700): Use a ternary once it no longer confuses our nullness checker.
    if (value == null) {
      return getWithoutCaching(key);
    } else {
      return value;
    }
  }