[#109] Implemented more map functionality

* implemented AutoCloseable close
* implemented Map clear, size, containsValue, isEmpty

examples/simple-deps/src/java_map.clj

@@ -1,56 +1,105 @@
 (ns java-map
-  (:require [datalevin.core :as d]))
-
-
-(defn ->map 
-  "Provide an implementation of java.util.Map interface backed by datalevin / LMDB."
-  [db table]
-  (d/open-dbi db table)
-  (reify java.util.Map
-
-    (clear [_this]
-      (throw (ex-info "Unimplemented" {})))
-
-    (containsKey [_this key]
-      (let [kv (d/get-value db table key :data :data false)]
-        (some? kv)))
-
-    (containsValue [_this value]
-      (throw (ex-info "Unimplemented" {})))
-
-    (entrySet [_this]
-      (throw (ex-info "Unimplemented" {})))
-
-    (get [_this key]
-      (d/get-value db table key))
-
-    (isEmpty [_this]
-      (throw (ex-info "Unimplemented" {})))
-
-    (keySet [_this]
-      (throw (ex-info "Unimplemented" {})))
-
-    (put [_this key value]
-      (d/transact-kv db [[:put table key value]]))
-
-    (remove [_this key]
-      (let [kv (d/get-value db table key :data :data false)]
-        (when (some? kv)
-          (d/transact-kv db [[:del table key :data]])
-          (nth kv 1))))
-
-    (size [_this]
-      (throw (ex-info "Unimplemented" {})))
-
-    (values [_this]
-      (throw (ex-info "Unimplemented" {})))))
+  (:require [datalevin.core :as d]
+            [datalevin.interpret :as i]))
+
+
+(defn ->map
+  "Provide an implementation of java.util.Map interface backed by datalevin / LMDB.
+   
+   Implements java.lang.AutoCloseable and can participate in with-open. 
+   However,successive open/close operations have a performance impact so be mindfull of this.
+   
+   IMPORTANT: map keys should not excede 510 bytes (LMDB limitation)
+
+   `db-or-path` - instance of ^datalevin.binding.java.LMDB or a string path / datalevin URI.
+   In case a path is provided, database is opened.
+   Pass :auto-close-db option to auto close when participating in with-open. 
+
+   `dbi` - name of sub-database to work on
+
+   `opts` is an options map that can have the following keys
+   * `db-opts` - datalevin options for opening LMDB database - pass to open-kv
+   "
+  [db-or-path ^:String dbi & {:keys [db-opts]
+                                :as _opts}]
+  (let [is-datalevin? (instance? datalevin.lmdb.ILMDB db-or-path)
+        db (if is-datalevin? db-or-path (d/open-kv db-or-path db-opts))
+        ;; do not close db when it's opened by client
+        auto-close-db (if is-datalevin? false true)]
+    (d/open-dbi db dbi)
+    (reify
+      java.lang.AutoCloseable
+      (close [_this]
+        (when auto-close-db
+          (d/close-kv db)))
+
+      java.util.Map
+
+      (clear [_this]
+        (d/clear-dbi db dbi))
+
+      (containsKey [_this key]
+        (let [kv (d/get-value db dbi key :data :data false)]
+          (some? kv)))
+
+      (containsValue [_this value]
+        (let [pred (i/inter-fn [kv]
+                               (let [v (d/read-buffer (d/v kv))]
+                                 (= v value)))]
+          (some? (d/get-some db dbi pred [:all]))))
+
+      (entrySet [_this]
+        (throw (ex-info "Unimplemented" {})))
+
+      (get [_this key]
+        (d/get-value db dbi key))
+
+      (isEmpty [_this]
+        (= 0 (d/entries db dbi)))
+
+      (keySet [_this]
+        (throw (ex-info "Unimplemented" {})))
+
+      (put [_this key value]
+        (d/transact-kv db [[:put dbi key value]]))
+
+      (remove [_this key]
+        (let [kv (d/get-value db dbi key :data :data false)]
+          (when (some? kv)
+            (d/transact-kv db [[:del dbi key :data]])
+            (nth kv 1))))
+
+      (size [_this]
+        (d/entries db dbi))
+
+      (values [_this]
+        (throw (ex-info "Unimplemented" {}))))))
 
 (comment
 
   (def db (d/open-kv "/tmp/datalevin/map"))
 
   (d/open-dbi db "map-table")
 
+  (instance? datalevin.lmdb.ILMDB db)
+
+  (with-open [m (->map "/tmp/datalevin/map2" "a")]
+    (println (.size m))
+    (println (.clear m))
+    (println (.size m))
+    (println (.put m 1 "a"))
+    (println (.containsValue m "a"))
+    (println (.containsValue m "b"))
+    (println (.size m)))
+
+  (with-open [m (->map "/tmp/datalevin/map2" "a")]
+    (println (.get m 1)))
+
+  (let [pred (i/inter-fn [kv]
+                         (let [v (d/read-buffer (d/v kv))]
+                           (= v "Is the secret number")))]
+    (d/get-some db "map-table" pred [:all]))
+
   (d/transact-kv
    db
    [[:put "map-table" :datalevin "Hello, world!"]
@@ -68,7 +117,7 @@
     (println (.get my-map 42))
     (.put my-map 36 "Is the secret number")
     (.get my-map 36)
-    (println (.remove my-map 36))
+    ;;(println (.remove my-map 36))
     (println (.containsKey my-map 36))
     (println (.containsKey my-map 3))
     (println (.containsKey my-map 42)))