implement symmetric validator

lib/goo/validators/enforce.rb

@@ -39,6 +39,8 @@ def enforce(inst,attr,value)
               check Goo::Validators::DataType, inst, attr, value, opt, DateTime
             when :float, Float
               check Goo::Validators::DataType, inst, attr, value, opt, Float
+            when :symmetric
+              check Goo::Validators::Symmetric, inst, attr, value, opt
             when Proc
               call_proc(opt, inst, attr)
             when /^max_/, /^min_/

lib/goo/validators/implementations/existence.rb

@@ -8,9 +8,12 @@ class Existence < ValidatorBase
       error_message ->(obj) { "`#{@value}` value cannot be nil"}
 
       validity_check -> (obj) do
-        not (@value.nil? || self.class.empty?(@value) || self.class.empty_array?(@value))
+        not self.class.empty_value?(@value)
       end
 
+      def self.empty_value?(value)
+        value.nil? || self.empty?(value) || self.empty_array?(value)
+      end
       def self.empty?(value)
         empty_string?(value) || empty_to_s?(value)
       end

lib/goo/validators/implementations/symmetric.rb

@@ -0,0 +1,44 @@
+module Goo
+  module Validators
+    class Symmetric < ValidatorBase
+      include Validator
+
+      key :symmetric
+
+      error_message ->(obj) {
+        "symmetric error"
+      }
+
+      validity_check -> (obj) do
+        return true if Existence.empty_value?(@value)
+
+        return Array(@value).select{|x| not self.class.symmetric?(@attr,x, @inst)}.empty?
+      end
+
+      def self.symmetric?(attr, value, source_object)
+        if self.respond_to?(attr, value)
+          target_values = self.attr_value(attr, value)
+          return target_values.any?{ |target_object| self.equivalent?(target_object, source_object)}
+        end
+
+        return false
+      end
+
+      def self.respond_to?(attr, object)
+        object && object.respond_to?(attr)
+      end
+
+      def self.attr_value(attr, object)
+        Array(object.send(attr))
+      end
+
+      def self.equivalent?(object1, object2)
+        if object1.respond_to?(:id) && object2.respond_to?(:id)
+          object1.id.eql?(object2.id)
+        else
+          object2 == object1
+        end
+      end
+    end
+  end
+end