mongo.rb in mongo_doc-0.4.1

- old
+ new

@@ -1,10 +1,10 @@
 module MongoDoc
   module Contexts
     class Mongo
       include Mongoid::Contexts::Paging
-      include MongoDoc::Contexts::Ids
+      include Mongoid::Contexts::Ids
 
       attr_reader :criteria, :cache
 
       delegate :klass, :options, :selector, :to => :criteria
       delegate :collection, :to => :klass
@@ -24,10 +24,29 @@
       # A +Hash+ with field values as keys, counts as values
       def aggregate
         collection.group(options[:fields], selector, { :count => 0 }, AGGREGATE_REDUCE, true)
       end
 
+      # Get the average value for the supplied field.
+      #
+      # This will take the internally built selector and options
+      # and pass them on to the Ruby driver's +group()+ method on the collection. The
+      # collection itself will be retrieved from the class provided, and once the
+      # query has returned it will provided a grouping of keys with averages.
+      #
+      # Example:
+      #
+      # <tt>context.avg(:age)</tt>
+      #
+      # Returns:
+      #
+      # A numeric value that is the average.
+      def avg(field)
+        total = sum(field)
+        total ? (total / count) : nil
+      end
+
       # Get the count of matching documents in the database for the context.
       #
       # Example:
       #
       # <tt>context.count</tt>
@@ -35,9 +54,19 @@
       # Returns:
       #
       # An +Integer+ count of documents.
       def count
         @count ||= collection.find(selector, options).count
+      end
+
+      # Gets an array of distinct values for the supplied field across the
+      # entire collection or the susbset given the criteria.
+      #
+      # Example:
+      #
+      # <tt>context.distinct(:title)</tt>
+      def distinct(field)
+        collection.distinct(field, selector)
       end
 
       # Determine if the context is empty or blank given the criteria. Will
       # perform a quick find_one asking only for the id.
       #