From 3963808152fdaad61e8e5896c445b4e194040d71 Mon Sep 17 00:00:00 2001
From: "Michael S. Klishin" <michael@novemberain.com>
Date: Sun, 16 Oct 2011 14:19:04 +0400
Subject: [PATCH] Introduce monger.collection/distinct

---
 src/monger/collection.clj       | 15 ++++++++++++++-
 test/monger/test/collection.clj | 17 +++++++++++++++++
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/src/monger/collection.clj b/src/monger/collection.clj
index 461580a..95ec797 100644
--- a/src/monger/collection.clj
+++ b/src/monger/collection.clj
@@ -8,7 +8,7 @@
 ;; You must not remove this notice, or any other, from this software.
 
 (ns monger.collection
-  (:refer-clojure :exclude [find remove count drop])
+  (:refer-clojure :exclude [find remove count drop distinct])
   (:import [com.mongodb Mongo DB DBCollection WriteResult DBObject WriteConcern DBCursor MapReduceCommand MapReduceCommand$OutputType]
            [java.util List Map]
            [clojure.lang IPersistentMap ISeq])
@@ -296,6 +296,19 @@
        (.mapReduce coll js-mapper js-reducer output output-type (to-db-object query)))))
 
 
+;;
+;; monger.collection/distinct
+;;
+
+(defn distinct
+  ([^String collection, ^String key]
+     (let [^DBCollection coll (.getCollection monger.core/*mongodb-database* collection)]
+       (.distinct coll ^String (to-db-object key))))
+  ([^String collection, ^String key, ^Map query]
+     (let [^DBCollection coll (.getCollection monger.core/*mongodb-database* collection)]
+       (.distinct coll ^String (to-db-object key) ^DBObject (to-db-object query)))))
+
+
 
 ;;
 ;; Implementation
diff --git a/test/monger/test/collection.clj b/test/monger/test/collection.clj
index 858ba54..17db479 100644
--- a/test/monger/test/collection.clj
+++ b/test/monger/test/collection.clj
@@ -552,3 +552,20 @@
       (is (= ["CA" "IL" "NY" "OR"]
              (map :_id (mgcol/find-maps "merged_mr_outputs"))))
       (.drop ^MapReduceOutput output))))
+
+
+;;
+;; distinct
+;;
+
+(deftest distinct-values
+  (let [collection "widgets"
+        batch      [{ :state "CA" :quantity 1 :price 199.00 }
+                    { :state "NY" :quantity 2 :price 199.00 }
+                    { :state "NY" :quantity 1 :price 299.00 }
+                    { :state "IL" :quantity 2 :price 11.50  }
+                    { :state "CA" :quantity 2 :price 2.95   }
+                    { :state "IL" :quantity 3 :price 5.50   }]]
+    (mgcol/insert-batch collection batch)
+    (is (= ["CA" "IL" "NY"] (sort (mgcol/distinct collection :state))))
+    (is (= ["CA" "NY"] (sort (mgcol/distinct collection :state { :price { "$gt" 100.00 } }))))))