class DictionaryAllWordsDataSource(//...) :
    PositionalDataSource<Meaning>() {
    //...
    override fun loadRange(params: LoadRangeParams, callback: LoadRangeCallback<Meaning>) {
        //...
              val startPage = (params.startPosition / PAGE_SIZE) + 1
              if (totalPages >= startPage) {
                  val words = getWordsFromPage(startPage, startPage)
                  if (words.isEmpty()) throw NoDataException()
                  callback.onResult(words)
              }
        //...
    }

    override fun loadInitial(params: LoadInitialParams, callback: LoadInitialCallback<Meaning>) {
        //...
              val total = getTotalPages()
              val endPage = min((params.requestedLoadSize / PAGE_SIZE), 3)
              val startPage = 1
              val words = getWordsFromPage(startPage, endPage)
              if (words.isEmpty()) throw NoDataException()
              callback.onResult(words, 0, (total.end * PAGE_SIZE))
              totalPages = total.end
        //...
    }

    fun getWordsFromPage(startPage: Int, endPage: Int): MutableList<Meaning> {
        val words = mutableListOf<Meaning>()
        for (index in startPage..endPage) {
            val dictionary = getWordsFromPage(index)
            dictionary.words.forEach { words.add(it) }
        }
        //...
        return words
    }

    private fun getWordsFromPage(pageNo: Int): Dictionary {
        //...
        return repository.getPageInDictionary(pageNo)
    }

    private fun getTotalPages(): Page {
        //...
        return repository.getNumberOfPagesInDictionary()
    }
}