Historically, the Chinese Empire was able to dominate its neighbors, due to its superior size, strength, and level of civilization. Adjoining countries which had accommodated at least some aspects of Chinese culture were treated (generally benignly) as vassal states; other nations were viewed purely as barbarians.
Western nations did not fit in this paradigm; hence, the Empire’s conceptual and practical difficulty in dealing with them.
While the ultimate scope of the international ambitions of the current Chinese state is not clear, it is reasonable to assume, based on its actions in the last few years, that its aspirations in the near abroad are consistent with China’s traditional behavior towards its neighbors. Call it the Xi Doctrine.