lib/bindata/single.rb in bindata-0.9.1 vs lib/bindata/single.rb in bindata-0.9.2

@@ -43,20 +43,15 @@
   #                           this criteria.  The variable +value+ is made
   #                           available to any lambda assigned to this
   #                           parameter.  A boolean return indicates success
   #                           or failure.  Any other return is compared to
   #                           the value just read in.
-  class Single < Base
+  class Single < BinData::Base
     # These are the parameters used by this class.
     optional_parameters :initial_value, :value, :check_value
     mutually_exclusive_parameters :initial_value, :value
 
-    # Single objects don't contain fields so this returns an empty list.
-    def self.all_possible_field_names(sanitized_params)
-      []
-    end
-
     def initialize(params = {}, env = nil)
       super(params, env)
       clear
     end
 
@@ -74,20 +69,10 @@
     # Single objects are single_values
     def single_value?
       true
     end
 
-    # Single objects don't contain fields so this returns an empty list.
-    def field_names
-      []
-    end
-
-    # Returns a snapshot of this data object.
-    def snapshot
-      value
-    end
-
     # To be called after calling #do_read.
     def done_read
       @in_read = false
     end
 
@@ -120,11 +105,11 @@
       # does the value meet expectations?
       if has_param?(:check_value)
         current_value = self.value
         expected = eval_param(:check_value, :value => current_value)
         if not expected
-          raise ValidityError, "value not as expected"
+          raise ValidityError, "value '#{current_value}' not as expected"
         elsif current_value != expected and expected != true
           raise ValidityError, "value is '#{current_value}' but " +
                                "expected '#{expected}'"
         end
       end
@@ -137,9 +122,14 @@
     end
 
     # Returns the number of bytes it will take to write this data.
     def _do_num_bytes(ignored)
       val_to_str(_value).length
+    end
+
+    # Returns a snapshot of this data object.
+    def _snapshot
+      value
     end
 
     # The unmodified value of this data object.  Note that #value calls this
     # method.  This is so that #value can be overridden in subclasses to 
     # modify the value.