module Ecoportal::API::Common::Content::ClassHelpers

Constants

NOT_USED

Public Instance Methods

inheritable_attrs(*attrs) click to toggle source

Builds the attr_reader and attr_writer of `attrs` and registers the associated instance variable as inheritable.

# File lib/ecoportal/api/common/content/class_helpers.rb, line 119
def inheritable_attrs(*attrs)
  attrs.each do |attr|
    class_eval %(
      class << self; attr_accessor :#{attr} end
    )
  end
  inheritable_class_vars(*attrs)
end
inheritable_class_vars(*vars) click to toggle source

Keeps track on class instance variables that should be inherited by child classes. @note

- subclasses will inherit the value as is at that moment
- any change afterwards will be only on the specific class (in line with class instance variables)
- adapted from https://stackoverflow.com/a/10729812/4352306

TODO: this separates the logic of the method to the instance var. Think if would be possible to join them somehow.

# File lib/ecoportal/api/common/content/class_helpers.rb, line 113
def inheritable_class_vars(*vars)
  @inheritable_class_vars ||= [:inheritable_class_vars]
  @inheritable_class_vars += vars
end
inherited(subclass) click to toggle source

This callback method is called whenever a subclass of the current class is created. @note

- values of the instance variables are copied as they are (no dups or clones)
- the above means: avoid methods that change the state of the mutable object on it
- mutating methods would reflect the changes on other classes as well
- therefore, `freeze` will be called on the values that are inherited.
# File lib/ecoportal/api/common/content/class_helpers.rb, line 134
def inherited(subclass)
  inheritable_class_vars.each do |var|
    instance_var = instance_variable_name(var)
    value        = instance_variable_get(instance_var)
    subclass.instance_variable_set(instance_var, value.freeze)
  end
end
instance_variable_name(name) click to toggle source

Helper to create an instance variable `name` @param [String, Symbol] the name of the variable @reutrn [String] the name of the created instance variable

# File lib/ecoportal/api/common/content/class_helpers.rb, line 46
def instance_variable_name(name)
  str = name.to_s
  str = "@#{str}" unless str.start_with?("@")
  str
end
new_class(name, inherits:) { |klass| ... } click to toggle source

If the class for `name` exists, it returns it. Otherwise it generates it. @param name [String, Symbol] the name of the new class @param inherits [Class] the parent class to inherit from @yield [child_class] configure the new class @yieldparam child_class [Class] the new class @return [Class] the new generated class

# File lib/ecoportal/api/common/content/class_helpers.rb, line 58
def new_class(name, inherits:)
  name            = name.to_sym.freeze
  class_name      = to_constant(name)
  full_class_name = "#{inherits}::#{class_name}"

  unless target_class = resolve_class(full_class_name, exception: false)
    target_class = Class.new(inherits)
    self.const_set class_name, target_class
  end

  target_class.tap do |klass|
    yield(klass) if block_given?
  end
end
resolve_class(klass, exception: true) click to toggle source

Class resolver @note it caches the resolved `klass`es @raise [Exception] when could not resolve if `exception` is `true` @param klass [Class, String, Symbol] the class to resolve @param exception [Boolean] if it should raise exception when could not resolve @return [Class] the `Class` constant

# File lib/ecoportal/api/common/content/class_helpers.rb, line 15
def resolve_class(klass, exception: true)
  @resolved ||= {}
  @resolved[klass] ||=
    case klass
      when Class
        klass
      when String
        begin
          Kernel.const_get(klass)
        rescue NameError => e
          raise if exception
        end
      when Symbol
        resolve_class(self.send(klass))
      else
        raise "Unknown class: #{klass}" if exception
    end
end
to_constant(key) click to toggle source

Helper to normalize `key` into a correct `ruby` **constant name** @param key [String, Symbol] to be normalized @return [String] a correct constant name

# File lib/ecoportal/api/common/content/class_helpers.rb, line 37
def to_constant(key)
  str_name = key.to_s.strip.split(/[\-\_ ]/i).compact.map do |str|
    str.slice(0).upcase + str.slice(1..-1).downcase
  end.join("")
end
to_time(value, exception: true) click to toggle source

Helper to parse a value into a `Time` object. @raise [Exception] if `exception` is `true` and could not convert @param value [String, Date] the value to convert to `Time` @param exception [Boolean] if should raise `Exception` when could not convert @return

# File lib/ecoportal/api/common/content/class_helpers.rb, line 78
def to_time(value, exception: true)
  case value
  when NilClass
    value
  when String
    begin
      Time.parse(value)
    rescue ArgumentArgument => e
      raise if exception
      nil
    end
  when Date
    Time.parse(value.to_s)
  when Time
    value
  else
    to_time(value.to_s) if value.respond_to?(:to_s)
  end
end
used_param?(val) click to toggle source

Helper to determine if a paramter has been used @note to effectivelly use this helper, you should initialize your target

paramters with the constant `NOT_USED`

@param val [] the value of the paramter @return [Boolean] `true` if value other than `NOT_USED`, `false` otherwise

# File lib/ecoportal/api/common/content/class_helpers.rb, line 103
def used_param?(val)
  val != NOT_USED
end