Decorators for AsyncConsistentMap

Change-Id: Ie5f325ecb825951456bd950055ba88bb93af01b6
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/Hasher.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/Hasher.java
new file mode 100644
index 0000000..96de934
--- /dev/null
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/impl/Hasher.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2016 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onosproject.store.primitives.impl;
+
+import org.onosproject.cluster.PartitionId;
+
+/**
+ * Interface for mapping from an object to {@link PartitionId}.
+ *
+ * @param <K> object type.
+ */
+public interface Hasher<K> {
+    /**
+     * Returns the {@link PartitionId} to which the specified object maps.
+     * @param object object
+     * @return partition identifier
+     */
+    PartitionId hash(K object);
+}