1 files changed, 46 insertions, 0 deletions
diff --git a/ruby/fields.rb b/ruby/fields.rb
new file mode 100644
index 0000000000..c46ba645ee
--- /dev/null
+++ b/ruby/fields.rb
@@ -0,0 +1,46 @@
+#
+# Copyright (c) 2006 The Apache Software Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+class Class
+  def fields(*fields)
+    module_eval {
+      def initialize(*args, &block)
+        args = init_fields(*args)
+
+        if respond_to? :init
+          init(*args) {|*a| yield(*a)}
+        elsif args.any?
+          raise ArgumentException.new("extra arguments: #{args}")
+        end
+      end
+    }
+
+    vars = fields.map {|f| :"@#{f.to_s().chomp("?")}"}
+
+    define_method(:init_fields) {|*args|
+      vars.each {|v|
+        instance_variable_set(v, args.shift())
+      }
+      args
+    }
+
+    vars.each_index {|i|
+      define_method(fields[i]) {
+        instance_variable_get(vars[i])
+      }
+    }
+  end
+end