support java Bigdecimal in mongodb 3.4 or later

project.clj

@@ -5,7 +5,7 @@
   :license {:name "Eclipse Public License"
             :url "http://www.eclipse.org/legal/epl-v10.html"}
   :dependencies [[org.clojure/clojure        "1.8.0"]
-                 [org.mongodb/mongodb-driver "3.4.2"]
+                 [org.mongodb/mongodb-driver "3.6.0-beta2"]
                  [clojurewerkz/support       "1.1.0"]]
   :test-selectors {:default     (fn [m]
                                   (and (not (:performance m))

src/clojure/monger/conversion.clj

@@ -46,7 +46,8 @@
   (:import [com.mongodb DBObject BasicDBObject BasicDBList DBCursor]
            [clojure.lang IPersistentMap Named Keyword Ratio]
            [java.util List Map Date Set]
-           org.bson.types.ObjectId))
+           org.bson.types.ObjectId
+           (org.bson.types Decimal128)))
 
 (defprotocol ConvertToDBObject
   (^com.mongodb.DBObject to-db-object [input] "Converts given piece of Clojure data to BasicDBObject MongoDB Java driver uses"))
@@ -104,7 +105,6 @@
 
 
 
-
 (defprotocol ConvertFromDBObject
   (from-db-object [input keywordize] "Converts given DBObject instance to a piece of Clojure data"))
 
@@ -115,6 +115,11 @@
   Object
   (from-db-object [input keywordize] input)
 
+  Decimal128
+  (from-db-object [^Decimal128 input keywordize]
+    (.bigDecimalValue input)
+    )
+
   List
   (from-db-object [^List input keywordize]
     (vec (map #(from-db-object % keywordize) input)))
@@ -140,7 +145,6 @@
             {} (.keySet input))))
 
 
-
 (defprotocol ConvertToObjectId
   (^org.bson.types.ObjectId to-object-id [input] "Instantiates ObjectId from input unless the input itself is an ObjectId instance. In that case, returns input as is."))
 

test/monger/test/conversion_test.clj

@@ -4,7 +4,8 @@
             [monger.conversion :refer :all])
   (:import [com.mongodb DBObject BasicDBObject BasicDBList]
            [java.util Date Calendar List ArrayList]
-           org.bson.types.ObjectId))
+           org.bson.types.ObjectId
+           (org.bson.types Decimal128)))
 
 
 ;;
@@ -101,6 +102,13 @@
   (is (= 2 (from-db-object 2 false)))
   (is (= 2 (from-db-object 2 true))))
 
+(deftest convert-decimal-from-dbobject
+  (is (= 2.3M (from-db-object (Decimal128. 2.3M) false)))
+  (is (= 2.3M (from-db-object (Decimal128. 2.3M) true)))
+  (is (= 2.3M (from-db-object (Decimal128/parse "2.3") true)))
+  (is (not= 2.32M (from-db-object (Decimal128/parse "2.3") true)))
+  )
+
 (deftest convert-float-from-dbobject
   (is (= 3.3 (from-db-object 3.3 false)))
   (is (= 3.3 (from-db-object 3.3 true))))