Adding missing $nin operator.

src/monger/operators.clj

@@ -37,6 +37,13 @@
 ;;   (mgcol/find-maps "languages" { :tags { $in [ "functional" "object-oriented" ] } } )
 (defoperator $in)
 
+;; The $nin operator is similar to $in, but it selects objects for which the specified field does not
+;; have any value in the specified array.
+;;
+;; EXAMPLES
+;;   (mgcol/find-maps "languages" { :tags { $nin [ "functional" ] } } )
+(defoperator $nin)
+
 ;; $ne is "non-equals" comparator
 ;;
 ;; EXAMPLES:

test/monger/test/query_operators.clj

@@ -1,6 +1,6 @@
 (set! *warn-on-reflection* true)
 
-(ns monger.test.collection
+(ns monger.test.query-operators
   (:import  [com.mongodb WriteResult WriteConcern DBCursor DBObject CommandResult$CommandFailure MapReduceOutput MapReduceCommand MapReduceCommand$OutputType]
             [org.bson.types ObjectId]
             [java.util Date])
@@ -68,7 +68,7 @@
                                                   {:users { $gt 10 } } ]}))))))
 
 ;;
-;; $all, $in
+;; $all, $in, $nin
 ;;
 
 (deftest find-on-embedded-arrays
@@ -78,7 +78,8 @@
                                     { :language "Ruby",    :tags [ "object-oriented" "dynamic" ] }])
 
     (is (= "Scala" (:language (first (mgcol/find-maps collection { :tags { $all [ "functional" "object-oriented" ] } } )))))
-    (is (= 3 (.count (mgcol/find-maps collection { :tags { $in [ "functional" "object-oriented" ] } } ))))))
+    (is (= 3 (.count (mgcol/find-maps collection { :tags { $in [ "functional" "object-oriented" ] } } ))))
+    (is (= 1 (.count (mgcol/find-maps collection { :tags { $nin [ "functional" ] } } ))))))
 
 
 (deftest find-with-conditional-operators-on-embedded-documents
@@ -93,4 +94,4 @@
     (are [a b] (= a (.count (mgcol/find collection b)))
          1 { :comments { $elemMatch { :text "Nice!" :rating { $gte 1 } } } }
          2 { "comments.rating" 1 }
-         1 { "comments.rating" { $gt 3 } })))
+         1 { "comments.rating" { $gt 3 } })))