lib/progression.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # This file is free software, which comes along with NIT. This software is
   4 # distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
   5 # without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
   6 # PARTICULAR PURPOSE. You can modify it is you want, provided this header
   7 # is kept unaltered, and a notification of the changes is added.
   8 # You are allowed to redistribute it and sell it, alone or is a part of
   9 # another product.
  10
  11 # Event-based interface to track the progression of an operation.
  12 module progression
  13
  14 # An operation that is trackable using a `ProgressionListener`.
  15 abstract class Trackable
  16
  17         # Listen to the progression of the operation.
  18         var progression_listeners: SimpleCollection[ProgressionListener] =
  19                         new Array[ProgressionListener]
  20
  21         # Notice the registered `ProgessionListener` that the operation started.
  22         protected fun fire_started do
  23                 for l in progression_listeners do
  24                         l.started
  25                         l.progressed(0)
  26                 end
  27         end
  28
  29         # Notice the registered `ProgessionListener` that the operation progressed.
  30         #
  31         # Parameter:
  32         #
  33         # * `done_part`: Indicates what is done.
  34         # * `total`: Indicates what need to be done, `done_part` included.
  35         protected fun fire_progressed(done_part: Int, total: Int) do
  36                 for l in progression_listeners do
  37                         l.progressed(done_part * l.progression_max / total)
  38                 end
  39         end
  40
  41         # Notice the registered `ProgessionListener` that the operation is done.
  42         protected fun fire_done do
  43                 for l in progression_listeners do
  44                         l.progressed(l.progression_max)
  45                         l.done
  46                 end
  47         end
  48 end
  49
  50 # Listens to the progression of a possibly long-running operation.
  51 interface ProgressionListener
  52         # The number that represents a completed operation.
  53         fun progression_max: Int do return 100
  54
  55         # The operation started.
  56         fun started do end
  57
  58         # The operation progressed.
  59         #
  60         # Parameter:
  61         #
  62         # * `progression`: Indicator of the progession, between `0` and
  63         # `progression_max`.
  64         fun progressed(progression: Int) do end
  65
  66         # The operation is done.
  67         fun done do end
  68 end