diff --git a/lib/rack/filter_param.rb b/lib/rack/filter_param.rb
index c6f9180..0828705 100644
--- a/lib/rack/filter_param.rb
+++ b/lib/rack/filter_param.rb
@@ -1,86 +1,14 @@
-require "rack/filter_param/version"
+require 'rack/filter_param/version'
+require 'rack/filter_param/middleware'
+require 'rack/filter_param/filter'
+require 'rack/filter_param/apply_filter'
 
 module Rack
-  class FilterParam
+  module FilterParam
     ACTION_DISPATCH_KEY = 'action_dispatch.request.request_parameters'.freeze
     FILTERED_PARAMS_KEY = 'rack.filtered_params'.freeze
 
-    def initialize(app, *params)
-      @app = app
-      @params = params.flatten
-    end
-
-    def call(env)
-      @request = Rack::Request.new(env)
-      @params.each { |param| process_param(param) }
-
-      @app.call(env)
-    end
-
-    private
-
-    attr_reader :request
-
-    def process_param(param)
-      return unless path_matches?(param)
-      return unless param_exists?(param)
-      return unless affirmative_conditional?(param)
-
-      param = param[:param] if param.is_a?(Hash)
-
-      if delete_from_action_dispatch(param) || delete_from_request(param)
-        filtered_params << [ param.to_s, nil ]
-      end
-    end
-
-    def path_matches?(param)
-      return true unless param.is_a?(Hash)
-
-      path = param[:path]
-      return true unless path = param[:path]
-
-      return request.env['PATH_INFO'] == path if path.is_a?(String)
-      return request.env['PATH_INFO'] =~ path if path.is_a?(Regexp)
-
-      false
-    end
-
-    def param_exists?(param)
-      param = param.is_a?(Hash) ? param[:param] : param
-      params.has_key?(param.to_s)
-    end
-
-    def params
-      action_dispatch_parsed? ? action_dispatch_params : request.params
-    end
-
-    def affirmative_conditional?(param)
-      return true unless param.is_a?(Hash)
-
-      callable, param = param[:if], param[:param]
-      return true if callable.nil?
-
-      callable.call(params[param.to_s])
-    end
-
-    def delete_from_action_dispatch(param)
-      action_dispatch_parsed? && !!action_dispatch_params.delete(param.to_s)
-    end
-
-    def delete_from_request(param)
-      !!request.delete_param(param.to_s)
-    end
-
-    def action_dispatch_params
-      request.env[ACTION_DISPATCH_KEY]
-    end
-
-    def action_dispatch_parsed?
-      !action_dispatch_params.nil?
-    end
-
-    def filtered_params
-      request.env[FILTERED_PARAMS_KEY] ||= []
-    end
+    extend SingleForwardable
+    def_delegators :'Rack::FilterParam::Middleware', :new
   end
 end
diff --git a/lib/rack/filter_param/apply_filter.rb b/lib/rack/filter_param/apply_filter.rb
new file mode 100644
index 0000000..0d3f34b
--- /dev/null
+++ b/lib/rack/filter_param/apply_filter.rb
@@ -0,0 +1,73 @@
+module Rack
+  class ApplyFilter
+    extend Forwardable
+
+    def initialize(filter, request)
+      @filter  = filter
+      @request = request
+    end
+
+    def call
+      return unless param_exists?
+      return unless path_matches?
+      return unless if_proc_affirmative?
+
+      if delete_from_action_dispatch || delete_from_request
+        filtered_params << [ param, nil ]
+      end
+    end
+
+    private
+    attr_reader :filter, :request
+
+    def_delegators :@filter, :param, :path, :if_proc
+    def_delegators :@request, :env
+
+    def params
+      action_dispatch_parsed? ? action_dispatch_params : request.params
+    end
+
+    def param_exists?
+      params.has_key?(param)
+    end
+
+    def param_value
+      params[param]
+    end
+
+    def action_dispatch_params
+      env[FilterParam::ACTION_DISPATCH_KEY]
+    end
+
+    def action_dispatch_parsed?
+      !action_dispatch_params.nil?
+    end
+
+    def path_matches?
+      return true if path.nil?
+
+      return env['PATH_INFO'] == path if path.is_a?(String)
+      return env['PATH_INFO'] =~ path if path.is_a?(Regexp)
+
+      false
+    end
+
+    def if_proc_affirmative?
+      return true if if_proc.nil?
+
+      if_proc.call(param_value)
+    end
+
+    def delete_from_action_dispatch
+      action_dispatch_parsed? && !!action_dispatch_params.delete(param)
+    end
+
+    def delete_from_request
+      !!request.delete_param(param)
+    end
+
+    def filtered_params
+      env[FilterParam::FILTERED_PARAMS_KEY] ||= []
+    end
+  end
+end
diff --git a/lib/rack/filter_param/filter.rb b/lib/rack/filter_param/filter.rb
new file mode 100644
index 0000000..7d43c32
--- /dev/null
+++ b/lib/rack/filter_param/filter.rb
@@ -0,0 +1,21 @@
+module Rack
+  class Filter
+    attr_reader :param, :path, :if_proc
+
+    def initialize(options)
+      if options.is_a?(Hash)
+        @param   = parse_param(options[:param])
+        @path    = options[:path]
+        @if_proc = options[:if]
+      else
+        @param   = parse_param(options)
+      end
+    end
+
+    private
+
+    def parse_param(param)
+      param.is_a?(Symbol) ? param.to_s : param
+    end
+  end
+end
diff --git a/lib/rack/filter_param/middleware.rb b/lib/rack/filter_param/middleware.rb
new file mode 100644
index 0000000..cd3266b
--- /dev/null
+++ b/lib/rack/filter_param/middleware.rb
@@ -0,0 +1,17 @@
+module Rack
+  module FilterParam
+    class Middleware
+      def initialize(app, *filters)
+        @app = app
+        @filters = filters.flatten.map(&Filter.public_method(:new))
+      end
+
+      def call(env)
+        request = Request.new(env)
+
+        @filters.each { |filter| ApplyFilter.new(filter, request).call }
+        @app.call(env)
+      end
+    end
+  end
+end
diff --git a/lib/rack/filter_param/version.rb b/lib/rack/filter_param/version.rb
index 33ce8e8..4090048 100644
--- a/lib/rack/filter_param/version.rb
+++ b/lib/rack/filter_param/version.rb
@@ -1,5 +1,5 @@
 module Rack
-  class FilterParam
+  module FilterParam
     VERSION = "0.2.1"
   end
 end
diff --git a/spec/rack/filter_param_spec.rb b/spec/rack/filter_param_spec.rb
index 6acd6de..1e3aad9 100644
--- a/spec/rack/filter_param_spec.rb
+++ b/spec/rack/filter_param_spec.rb
@@ -7,7 +7,7 @@ RSpec.describe Rack::FilterParam do
   let(:headers)         { {} }
   let(:rack_env)        { {} }
   let(:params_to_test)  {
-    last_request.env[described_class::ACTION_DISPATCH_KEY] || last_request.params
+    last_request.env[Rack::FilterParam::ACTION_DISPATCH_KEY] || last_request.params
   }
 
   before {
@@ -225,7 +225,7 @@ RSpec.describe Rack::FilterParam do
     let(:params) { super().to_json }
 
     let(:rack_env) {
-      { described_class::ACTION_DISPATCH_KEY => params }
+      { Rack::FilterParam::ACTION_DISPATCH_KEY => params }
     }
 
     describe 'basic functionality' do