view/config/config_element.rb

# config_element.rb: the class definition of Edmaru::ConfigElement
#
# Copyright (C) 2007 Takashi Nakamoto
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA.
#

module Edmaru::Config

  #Instances of this class represents one configuration.
  class ConfigElement

    #Initializer.
    #
    #=== Arguments
    #_key_ :: The unique key of this element.
    #_default_ :: Default value.
    #_desc_ :: Description.
    #_validator_ :: An instance of Proc.
    #
    #=== About _key_
    #The _key_ should have hierarchical structure. So all hierarycies
    #should be separated by slash characters("/") and it should start
    #with a slash character("/") like an absolute path of Unix.
    #
    #For example: "/UI/Gtk/Font"
    #
    #=== About _validator_
    #ToDo: write about _validator_
    #
    #=== Return
    #An initialized instance of Edmaru::ConfigElement.
    def initialize(key, default, desc, validator)
      @key = key
      @default_value = default
      @use_default = true
      @description = desc
      @validator = validator
    end

    def key
      @key
    end

    def value
      if @use_default
        return @default_value
      else
        return @value
      end
    end

    def value=(new_value)
      #Check if the passed value is valid or not.
      begin
        @validator.call(new_value)
      rescue => e
        raise e
      end

      @use_default = false
      @value = new_value
    end

    def description
      @description
    end
  end
end