Module: Sequel::Plugins::Composition::ClassMethods

Attributes

composition_module	[R]	A module included in the class holding the composition getter and setter methods.
compositions	[R]	A hash with composition name keys and composition reflection hash values.

Public Instance methods

composition(name, opts={})

Define a composition for this model, with name being the name of the composition. You must provide either a :mapping option or both the :composer and :decomposer options.

Options:

:class - if using the :mapping option, the class to use, as a Class, String or Symbol.
:composer - A proc that is instance evaled when the composition getter method is called to create the composition.
:decomposer - A proc that is instance evaled before saving the model object, if the composition object exists, which sets the columns in the model object based on the value of the composition object.

:mapping - An array where each element is either a symbol or an array of two symbols. A symbol is treated like an array of two symbols where both symbols are the same. The first symbol represents the getter method in the model, and the second symbol represents the getter method in the composition object. Example:

  # Uses columns year, month, and day in the current model
  # Uses year, month, and day methods in the composition object
  :mapping=>[:year, :month, :day]
  # Uses columns year, month, and day in the current model
  # Uses y, m, and d methods in the composition object where
  # for example y in the composition object represents year
  # in the model object.
  :mapping=>[[:year, :y], [:month, :m], [:day, :d]]

[Source]

     # File lib/sequel/plugins/composition.rb, line 93
 93:         def composition(name, opts={})
 94:           opts = opts.dup
 95:           compositions[name] = opts
 96:           if mapping = opts[:mapping]
 97:             keys = mapping.map{|k| k.is_a?(Array) ? k.first : k}
 98:             if !opts[:composer]              
 99:               late_binding_class_option(opts, name)
100:               klass = opts[:class]
101:               class_proc = proc{klass || constantize(opts[:class_name])}
102:               opts[:composer] = proc do
103:                 if values = keys.map{|k| send(k)} and values.any?{|v| !v.nil?}
104:                   class_proc.call.new(*values)
105:                 else
106:                   nil
107:                 end
108:               end
109:             end
110:             if !opts[:decomposer]
111:               setter_meths = keys.map{|k| "#{k}=""#{k}="}
112:               cov_methods = mapping.map{|k| k.is_a?(Array) ? k.last : k}
113:               setters = setter_meths.zip(cov_methods)
114:               opts[:decomposer] = proc do
115:                 if (o = compositions[name]).nil?
116:                   setter_meths.each{|sm| send(sm, nil)}
117:                 else
118:                   setters.each{|sm, cm| send(sm, o.send(cm))}
119:                 end
120:               end
121:             end
122:           end
123:           raise(Error, "Must provide :composer and :decomposer options, or :mapping option") unless opts[:composer] && opts[:decomposer]
124:           define_composition_accessor(name, opts)
125:         end

define_composition_accessor(name, opts={})

Define getter and setter methods for the composition object.

[Source]

     # File lib/sequel/plugins/composition.rb, line 130
130:         def define_composition_accessor(name, opts={})
131:           include(@composition_module ||= Module.new) unless composition_module
132:           composer = opts[:composer]
133:           composition_module.class_eval do
134:             define_method(name) do 
135:               if compositions.has_key?(name)
136:                 compositions[name]
137:               elsif frozen?
138:                 instance_eval(&composer)
139:               else
140:                 compositions[name] = instance_eval(&composer)
141:               end
142:             end
143:             define_method("#{name}=") do |v|
144:               modified!
145:               compositions[name] = v
146:             end
147:           end
148:         end