R/DataCache.R

In frbl/OnlineSuperLearner: Online SuperLearner package

#' DataCache
#'
#' Class that is used internally to manage datacaching
#'
#' @docType class
#' @importFrom R6 R6Class
#'
#' @section Methods:
#' \describe{
#'   \item{\code{initialize(online = TRUE)}}{
#'     Creates a new data cache. Can be online (so new data gets overwritten),
#'     or offline (so new data gets appended).
#'     @param online (default = TRUE) boolean whether the data cache is online or offline.
#'   }
#'
#'   \item{\code{update_cache(newdata}}{
#'     Updates the data cache with the new blocks This function only
#'     updates the cache if not all estimators are online. It tells the user
#'     if it has updated by the boolean it returns.
#'     @param newdata data.table the new data to add to the cache (or to
#'      replace the cache with)
#'     @return boolean whether or not it actually needed to update the cache
#'      (FALSE if the cache is online).
#'   }
#'
#'   \item{\code{is_online}}{
#'     Active method. Function to check whether the cache is an online cache or
#'     offline cache.
#'     @return boolean whether the cache is online (TRUE) or offline (FALSE).
#'   }
#'
#'   \item{\code{get_data_cache}}{
#'     Active method. Function that returns the complete cache that is being
#'     tracked in the object.
#'     @return boolean whether the cache is online (TRUE) or offline (FALSE).
#'   }
#' }
DataCache <- R6Class("DataCache",
  public =
    list(
      initialize = function(online = TRUE) {
        private$online = online
      },

      update_cache = function(newdata) {
        if (self$is_online) {
          ## If we are truly online, just cache the last entry
          private$data_cache <- newdata
          return(FALSE)
        }
        private$data_cache <- rbindlist(list(self$get_data_cache, newdata))
        return(TRUE)
      }
    ),
  active =
    list(
      is_online = function() {
        private$online 
      },

      get_data_cache = function() {
        return(private$data_cache)
      }
    ),
  private =
    list(
      online = NULL,
      data_cache = NULL
    )
)