RxPaging.kt

class RxPaging {
    var page = 1
    val cache = CacheBuilder.newBuilder().build<Any, Single<List<Single<Int>>>>()


    @Test
    fun getPages() {
        val tab1 = pagedList().blockingGet().iterator()
        val tab2 = pagedList().blockingGet().iterator()

        val a = tab1.next().test().assertValue(1)
        val b = tab2.next().test().assertValue(1)
        val c = tab1.next().test().assertValue(2)
        val d = tab1.next().test().assertValue(3)
        val e = tab2.next().test().assertValue(2)

    }

    private fun pagedList() = cache.get("", { dbPages() })!!
    private fun dbPages() = Single.just(listOf(dbPage(), dbPage(), dbPage())).cache()
    private fun dbPage() = Single.fromCallable { nextPage() }.cache() //replace with DAO.getItems(offset,pageSize)
    private fun nextPage(): Int = page++
}