# File lib/FileCache.rb, line 115
def force_native_file_to_cache(native_file,method_to_cache_on_native_file,extension)
  cache_filename=cache_name_for_native_file(native_file,extension)
  if ! File.exists?(cache_filename) then    
      local_file=File.open(cache_filename,"wb")      
      local_file<<native_file.send(method_to_cache_on_native_file)
      local_file.close        
    end
    return cache_filename
end