Add multikey_cache

1 files changed, 30 insertions, 0 deletions

diff --git a/src/multikey_cache.clj b/src/multikey_cache.clj
new file mode 100644
index 0000000..74822a8
--- /dev/null
+++ b/src/multikey_cache.clj
@@ -0,0 +1,30 @@
+(ns multikey-cache
+  (:import java.util.Collections
+           org.apache.commons.collections.map.LRUMap)
+  (:use    clojure.contrib.seq-utils
+           cache-dot-clj.cache
+           ))
+
+(defn multikey-lru-cache [f max-size]
+  {:f    f
+   :lru  (java.util.Collections/synchronizedMap (LRUMap. max-size))
+   })
+
+(defn get-keys [c keys]
+  (let [f         (:f c)
+        lru       (:lru c)
+        uncached  (filter (complement #(.containsKey lru %)) keys)]
+    (when-not (empty? uncached)
+      (doseq [[k v] (map list uncached (f uncached))]
+        (.put lru k v)))
+    (map #(.get lru %) keys)))
+
+(defn get-key [c key]
+  (first (get-keys c [key])))
+
+(defn has-key [c key]
+  (.containsKey (:lru c) key))
+
+(defn invalidate-key [c key]
+  (.remove (:lru c) key)
+  nil)