From c25609a5c354e967ec2d64e72b2365f16ac23300 Mon Sep 17 00:00:00 2001
From: "Michael S. Klishin" <michael@novemberain.com>
Date: Wed, 28 Dec 2011 19:46:29 +0400
Subject: [PATCH] monger.conversion/to-object-id

---
 src/monger/conversion.clj       | 26 +++++++++++++++++++++++---
 test/monger/test/conversion.clj | 13 ++++++++++++-
 2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/src/monger/conversion.clj b/src/monger/conversion.clj
index 7654e61..dd646f5 100644
--- a/src/monger/conversion.clj
+++ b/src/monger/conversion.clj
@@ -22,9 +22,10 @@
 ;; THE SOFTWARE.
 
 (ns monger.conversion
-  (:import (com.mongodb DBObject BasicDBObject BasicDBList DBCursor)
-           (clojure.lang IPersistentMap Keyword)
-           (java.util List Map)))
+  (:import [com.mongodb DBObject BasicDBObject BasicDBList DBCursor]
+           [clojure.lang IPersistentMap Keyword]
+           [java.util List Map Date]
+           [org.bson.types ObjectId]))
 
 (defprotocol ConvertToDBObject
   (to-db-object [input] "Converts given piece of Clojure data to BasicDBObject MongoDB Java driver uses"))
@@ -101,3 +102,22 @@
               (assoc m k (from-db-object v false))))
           {} (reverse pairs)))
 
+
+
+(defprotocol ConvertToObjectId
+  (to-object-id [input] "Instantiates ObjectId from input unless the input itself is an ObjectId instance. In that case, returns input as is."))
+
+(extend-protocol ConvertToObjectId
+  String
+  (to-object-id [^String input]
+    (ObjectId. input))
+
+  Date
+  (to-object-id [^Date input]
+    (ObjectId. input))
+
+  ObjectId
+  (to-object-id [^ObjectId input]
+    input))
+
+
diff --git a/test/monger/test/conversion.clj b/test/monger/test/conversion.clj
index d27fac8..2d15643 100644
--- a/test/monger/test/conversion.clj
+++ b/test/monger/test/conversion.clj
@@ -2,7 +2,8 @@
   (:require [monger core collection]
             [monger.conversion :as cnv])
   (:import [com.mongodb DBObject BasicDBObject BasicDBList]
-           [java.util Date Calendar List ArrayList])
+           [java.util Date Calendar List ArrayList]
+           [org.bson.types ObjectId])
   (:use [clojure.test]))
 
 
@@ -131,3 +132,13 @@
     (is (= (-> output (get "nested") (get "list")) ["red" "green" "blue"]))
     (is (= (-> output (get "nested") (get "dblist")) [0 1]))))
 
+
+
+;;
+;; ObjectId coercion
+;;
+
+(deftest test-conversion-to-object-id
+  (let [output (ObjectId. "4efb39370364238a81020502")]
+    (is (= output (cnv/to-object-id "4efb39370364238a81020502")))
+    (is (= output (cnv/to-object-id output)))))