Module | Sequel::Plugins::Composition::ClassMethods |
In: |
lib/sequel/plugins/composition.rb
|
compositions | [R] | A hash with composition name keys and composition reflection hash values. |
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_execed when the composition getter method is called to create the composition. |
:decomposer : | A proc that is instance_execed 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]]} |
# File lib/sequel/plugins/composition.rb, line 94 94: def composition(name, opts=OPTS) 95: opts = opts.dup 96: compositions[name] = opts 97: if mapping = opts[:mapping] 98: keys = mapping.map{|k| k.is_a?(Array) ? k.first : k} 99: if !opts[:composer] 100: late_binding_class_option(opts, name) 101: klass = opts[:class] 102: class_proc = proc{klass || constantize(opts[:class_name])} 103: opts[:composer] = proc do 104: if values = keys.map{|k| get_column_value(k)} and values.any?{|v| !v.nil?} 105: class_proc.call.new(*values) 106: else 107: nil 108: end 109: end 110: end 111: if !opts[:decomposer] 112: setter_meths = keys.map{|k| "#{k}=""#{k}="} 113: cov_methods = mapping.map{|k| k.is_a?(Array) ? k.last : k} 114: setters = setter_meths.zip(cov_methods) 115: opts[:decomposer] = proc do 116: if (o = compositions[name]).nil? 117: setter_meths.each{|sm| set_column_value(sm, nil)} 118: else 119: setters.each{|sm, cm| set_column_value(sm, o.public_send(cm))} 120: end 121: end 122: end 123: end 124: raise(Error, "Must provide :composer and :decomposer options, or :mapping option") unless opts[:composer] && opts[:decomposer] 125: define_composition_accessor(name, opts) 126: end
Define getter and setter methods for the composition object.
# File lib/sequel/plugins/composition.rb, line 131 131: def define_composition_accessor(name, opts=OPTS) 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_exec(&composer) 139: else 140: compositions[name] = instance_exec(&composer) 141: end 142: end 143: define_method("#{name}=") do |v| 144: modified! 145: compositions[name] = v 146: end 147: end 148: end
Freeze composition information when freezing model class.
# File lib/sequel/plugins/composition.rb, line 151 151: def freeze 152: compositions.freeze.each_value(&:freeze) 153: @composition_module.freeze 154: 155: super 156: end