[#109] This is exploratory work for providing map interface on top of…

… datalevin

examples/simple-deps/deps.edn

@@ -1,7 +1,8 @@
 {:paths ["src"]
- :deps {io.github.juji-io/datalevin #_{:git/tag "0.6.21"
+ :deps {datalevin/datalevin #_{:git/tag "0.6.21"
                                        :git/sha "41d1915eb67b1606aab4807058ff24bb41fdb8e8"}
-        {:local/root "../.."}
+        #_{:local/root "../.."}
+        {:mvn/version "0.8.9"}
         com.cognitect/transit-clj {:mvn/version "1.0.329"}}
  :aliases {:dev {:jvm-opts ["--add-opens=java.base/java.nio=ALL-UNNAMED"
                             "--add-opens=java.base/sun.nio.ch=ALL-UNNAMED"]}}}

examples/simple-deps/src/java_map.clj

@@ -0,0 +1,77 @@
+(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" {})))))
+
+(comment
+
+  (def db (d/open-kv "/tmp/datalevin/map"))
+
+  (d/open-dbi db "map-table")
+
+  (d/transact-kv
+   db
+   [[:put "map-table" :datalevin "Hello, world!"]
+    [:put "map-table" 42 {:saying "So Long, and thanks for all the fish"
+                          :source "The Hitchhiker's Guide to the Galaxy"}]
+    [:put "map-table" #inst "1991-12-25" "USSR broke apart" :instant]
+    [:put "map-table" #inst "1989-11-09" "The fall of the Berlin Wall" :instant]])
+
+  (d/get-value db "map-table" 1 :data :data false)
+  (d/get-value db "map-table" 36 :data :data false)
+
+  (d/transact-kv db [[:del "map-table" 36 :data]])
+
+  (let [my-map (->map db "map-table")]
+    (println (.get my-map 42))
+    (.put my-map 36 "Is the secret number")
+    (.get my-map 36)
+    (println (.remove my-map 36))
+    (println (.containsKey my-map 36))
+    (println (.containsKey my-map 3))
+    (println (.containsKey my-map 42)))
+
+  (d/close-kv db)
+  )

examples/simple-deps/src/kv.clj

@@ -1,4 +1,5 @@
-(ns kv)
+(ns kv 
+  (:require [datalevin.core :as d]))
 
 (require '[datalevin.core :as d])
 (import '[java.util Date])