R/ToLowerCasePipe.R

In bdpar: Big Data Preprocessing Architecture

#
# Bdpar provide a tool to easily build customized data flows to pre-process
# large volumes of information from different sources. To this end, bdpar allows
# to (i) easily use and create new functionalities and (ii) develop new data
# source extractors according to the user needs. Additionally, the package
# provides by default a predefined data flow to extract and preprocess the most
# relevant information (tokens, dates, ... ) from some textual sources (SMS,
# email, tweets, YouTube comments).
#
# Copyright (C) 2020-2022 Sing Group (University of Vigo)
#
# This program is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation, either version 3 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along with
# this program. If not, see <https://www.gnu.org/licenses/gpl-3.0.html>

#' @title Class to convert the data field of an Instance to lower case
#'
#' @description Class to convert the data field of an \code{\link{Instance}}
#' to lower case.
#'
#' @section Inherit:
#' This class inherits from \code{\link{GenericPipe}} and implements the
#' \code{pipe} abstract function.
#'
#' @seealso \code{\link{AbbreviationPipe}}, \code{\link{ContractionPipe}},
#'          \code{\link{File2Pipe}}, \code{\link{FindEmojiPipe}},
#'          \code{\link{FindEmoticonPipe}}, \code{\link{FindHashtagPipe}},
#'          \code{\link{FindUrlPipe}}, \code{\link{FindUserNamePipe}},
#'          \code{\link{GuessDatePipe}}, \code{\link{GuessLanguagePipe}},
#'          \code{\link{Instance}}, \code{\link{InterjectionPipe}},
#'          \code{\link{MeasureLengthPipe}}, \code{\link{GenericPipe}},
#'          \code{\link{ResourceHandler}}, \code{\link{SlangPipe}},
#'          \code{\link{StopWordPipe}}, \code{\link{StoreFileExtPipe}},
#'          \code{\link{TargetAssigningPipe}}, \code{\link{TeeCSVPipe}}
#'
#' @keywords NULL
#'
#' @import R6
#' @export ToLowerCasePipe

ToLowerCasePipe <- R6Class(

  "ToLowerCasePipe",

  inherit = GenericPipe,

  public = list(
    #'
    #' @description Creates a \code{\link{ToLowerCasePipe}} object.
    #'
    #' @param propertyName A \code{\link{character}} value. Name of the property
    #' associated with the \code{\link{GenericPipe}}.
    #' @param alwaysBeforeDeps A \code{\link{list}} value. The dependencies
    #' alwaysBefore (\code{\link{GenericPipe}s} that must be executed before
    #' this one).
    #' @param notAfterDeps A \code{\link{list}} value. The dependencies
    #' notAfter (\code{\link{GenericPipe}s} that cannot be executed after
    #' this one).
    #'
    initialize = function(propertyName = "",
                          alwaysBeforeDeps = list(),
                          notAfterDeps = list()) {

      if (!"character" %in% class(propertyName)) {
        bdpar.log(message = paste0("Checking the type of the 'propertyName' variable: ",
                                   class(propertyName)),
                  level = "FATAL",
                  className = class(self)[1],
                  methodName = "initialize")
      }

      if (!"list" %in% class(alwaysBeforeDeps)) {
        bdpar.log(message = paste0("Checking the type of the 'alwaysBeforeDeps' variable: ",
                                   class(alwaysBeforeDeps)),
                  level = "FATAL",
                  className = class(self)[1],
                  methodName = "initialize")
      }

      if (!"list" %in% class(notAfterDeps)) {
        bdpar.log(message = paste0("Checking the type of the 'notAfterDeps' variable: ",
                                   class(notAfterDeps)),
                  level = "FATAL",
                  className = class(self)[1],
                  methodName = "initialize")
      }

      super$initialize(propertyName, alwaysBeforeDeps, notAfterDeps)
    },
    #'
    #' @description Preprocesses the \code{\link{Instance}} to convert the
    #' data to lower case.
    #'
    #' @param instance A \code{\link{Instance}} value. The \code{\link{Instance}}
    #' to preprocess.
    #'
    #' @return The \code{\link{Instance}} with the modifications that have
    #' occurred in the pipe.
    #'
    pipe = function(instance) {

      if (!"Instance" %in% class(instance)) {
        bdpar.log(message = paste0("Checking the type of the 'instance' variable: ",
                                   class(instance)),
                  level = "FATAL",
                  className = class(self)[1],
                  methodName = "pipe")
      }

      instance$setData(self$toLowerCase(instance$getData()))

      instance
    },
    #'
    #' @description Converts the data to lower case
    #'
    #' @param data A \code{\link{character}} value. Text to preprocess.
    #'
    #' @return The data in lower case.
    #'
    toLowerCase = function(data) {

      if (!"character" %in% class(data)) {
        bdpar.log(message = paste0("Checking the type of the 'data' variable: ",
                                   class(data)),
                  level = "FATAL",
                  className = class(self)[1],
                  methodName = "toLowerCase")
      }

      tolower(data)
    }
  )
)