Added the ability to automatically do lookups by passing an integer ID to .new

lib/draper/base.rb

@@ -1,7 +1,7 @@
 module Draper
   class Base      
     require 'active_support/core_ext/class/attribute'
-    class_attribute :denied, :allowed, :source_class
+    class_attribute :denied, :allowed, :source_class, :model_class
     attr_accessor :model
     
     DEFAULT_DENIED = Object.new.methods
@@ -9,12 +9,19 @@ module Draper
     self.denied = DEFAULT_DENIED
 
     def initialize(input)
+      if input.instance_of?(Fixnum)
+        input = model_class.find(Fixnum)
+      end
       input.inspect
       self.class.source_class = input.class
       @model = input      
       build_methods
     end
     
+    def self.decorates(input)
+      self.model_class = input.to_s.classify.constantize
+    end
+    
     def self.denies(*input_denied)
       raise ArgumentError, "Specify at least one method (as a symbol) to exclude when using denies" if input_denied.empty?
       raise ArgumentError, "Use either 'allows' or 'denies', but not both." if self.allowed?

spec/base_spec.rb

@@ -4,7 +4,13 @@ require 'draper'
 describe Draper::Base do
   subject{ Draper::Base.new(source) }
   let(:source){ "Sample String" }    
-    
+
+  context(".decorates") do
+    it "sets the model class for the decorator" do
+      ProductDecorator.new(source).model_class == Product
+    end
+  end
+  
   it "should return the wrapped object when converted to a model" do
     subject.to_model.should == source
   end
@@ -26,6 +32,14 @@ describe Draper::Base do
     Draper::Base.new(source).to_param.should == 1
   end
   
+  context ".new" do
+    it "should lookup the associated model when passed an integer" do
+      pd = ProductDecorator.new(1)
+      pd.should be_instance_of(ProductDecorator)
+      pd.model.should be_instance_of(Product)
+    end
+  end
+  
   context ".decorate" do
     it "should return a collection of wrapped objects when given a collection of source objects" do
       sources = ["one", "two", "three"]

spec/samples/product_decorator.rb

@@ -0,0 +1,9 @@
+class Product
+  def self.find(id)
+    return Product.new
+  end
+end
+
+class ProductDecorator < Draper::Base
+  decorates :product
+end