resource_factory.rb in hyperclient-0.0.6

- old
+ new

@@ -12,11 +12,16 @@
     # Public: A factory method to build Resources. It will try to find a
     # Resource in the identity map or build a new one if does not exist.
     #
     # url - A String to identify the Resource
     # args - An Array to pass other arguments to the Resource initialization.
+    #
+    # Raises MissingURLException if no url given.
+    # Returns a Resource.
     def self.resource(url, *args)
+      raise MissingURLException.new(args) unless url
+
       identity_map.fetch(url) do |url|
         resource = Resource.new(url, *args)
         identity_map.update(url => resource)
         resource
       end
@@ -24,9 +29,24 @@
 
     private
     # Internal: Returns a Hash that acts as identity map.
     def self.identity_map
       @identity_map ||= {}
+    end
+  end
+
+  # Public: Exception that is raised when building a Resource without a URL.
+  class MissingURLException < StandardError
+    # Public: Initializes a MissingURLException
+    #
+    # args - An Array of the args the were to be used to build the Resource.
+    def initialize(args)
+      @args = args
+    end
+
+    # Public: Returns a String with the exception message.
+    def message
+      "Cannot build Resource without a URL, given args were: #{@args.inspect}"
     end
   end
 end
 
 require 'hyperclient/resource'