Cache Interface to talk to the whole app

DataStore.kt

interface DataStore<T> {

    fun modelListObservable(): Maybe<List<T>>

    fun modelObservable(id: String): Maybe<T>

    fun putModels(vararg models: T)

    fun clear()

    fun modelObservable(): Maybe<T>
            = modelListObservable().map {
        list -> list.get(0)
    }

    val isDataAvailableObservable: Single<Boolean>
        get() = modelObservable().isEmpty
                .map { !it }
}