Refactor.

lib/wice/grid_output_buffer.rb

@@ -1,8 +1,6 @@
 # encoding: utf-8
 module Wice
   class GridOutputBuffer < String #:nodoc:
-    attr_accessor :return_empty_strings_for_nonexistent_filters
-
     def initialize(*attrs)
       super(*attrs)
       @filters = HashWithIndifferentAccess.new
@@ -17,17 +15,19 @@ def add_filter(detach_with_id, filter_code)
       @filters[detach_with_id] = filter_code
     end
 
-    def filter_for(detach_with_id)
+    def filter_for(detach_with_id, return_empty_strings_for_nonexistent_filters = false)
       unless @filters.key? detach_with_id
-        if @return_empty_strings_for_nonexistent_filters
+        if return_empty_strings_for_nonexistent_filters
           return ''
         else
           fail WiceGridException.new("No filter with Detached ID '#{detach_with_id}'!")
         end
       end
-      if @filters[detach_with_id] == false
+
+      unless @filters[detach_with_id]
         fail WiceGridException.new("Filter with Detached ID '#{detach_with_id}' has already been requested once! There cannot be two instances of the same filter on one page")
       end
+
       res = @filters[detach_with_id]
       @filters[detach_with_id] = false
       res

lib/wice/helpers/wice_grid_view_helpers.rb

@@ -154,9 +154,7 @@ def generate_blank_slate(grid, rendering) #:nodoc:
         rendering.blank_slate_handler
       end
 
-      if rendering.find_one_for(:in_html) { |column| column.detach_with_id }
-        grid.output_buffer.return_empty_strings_for_nonexistent_filters = true
-      end
+      rendering.find_one_for(:in_html, true) { |column| column.detach_with_id }
     end
 
     def call_block(block, ar, extra_argument = nil)  #:nodoc:

spec/wice/lib/grid_output_buffer_spec.rb

@@ -34,5 +34,11 @@ module Wice
 
       expect { grid.filter_for('key') }.to raise_error
     end
+
+    it 'should filter_for return empty string' do
+      grid = GridOutputBuffer.new
+
+      expect(grid.filter_for('key', true)).to eq('')
+    end
   end
 end