Merge pull request #4 from unidev-platform/feature/weak-cache

Add basic weak cache

Author: denis256

unidev-common/src/main/java/com/unidev/platform/cache/WeakConcurrentCache.java

@@ -0,0 +1,25 @@
+package com.unidev.platform.cache;
+
+import lombok.Getter;
+
+import java.lang.ref.WeakReference;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * Weak concurrent cache
+ * @param <K>
+ * @param <V>
+ */
+@Getter
+public class WeakConcurrentCache<K, V> {
+    private final ConcurrentHashMap<K, WeakReference<V>> cache = new ConcurrentHashMap<>();
+
+    public void put(K key, V value) {
+        cache.put(key, new WeakReference<>(value));
+    }
+
+    public V get(K key) {
+        WeakReference<V> weakRef = cache.get(key);
+        return weakRef == null ? null : weakRef.get();
+    }
+}