Timestamp, OnosTimestamp and it's serializer

Change-Id: I02e3563229ddae8fc4b705c708f4066d82e24cf4
diff --git a/core/store/src/main/java/org/onlab/onos/store/serializers/OnosTimestampSerializer.java b/core/store/src/main/java/org/onlab/onos/store/serializers/OnosTimestampSerializer.java
new file mode 100644
index 0000000..812bc9d
--- /dev/null
+++ b/core/store/src/main/java/org/onlab/onos/store/serializers/OnosTimestampSerializer.java
@@ -0,0 +1,37 @@
+package org.onlab.onos.store.serializers;
+
+import org.onlab.onos.net.ElementId;
+import org.onlab.onos.store.impl.OnosTimestamp;
+
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.Serializer;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+
+/**
+ * Kryo Serializer for {@link OnosTimestamp}.
+ */
+public class OnosTimestampSerializer extends Serializer<OnosTimestamp> {
+
+    /**
+     * Default constructor.
+     */
+    public OnosTimestampSerializer() {
+        // non-null, immutable
+        super(false, true);
+    }
+    @Override
+    public void write(Kryo kryo, Output output, OnosTimestamp object) {
+        kryo.writeClassAndObject(output, object.id());
+        output.writeInt(object.termNumber());
+        output.writeInt(object.sequenceNumber());
+    }
+
+    @Override
+    public OnosTimestamp read(Kryo kryo, Input input, Class<OnosTimestamp> type) {
+        ElementId id = (ElementId) kryo.readClassAndObject(input);
+        final int term = input.readInt();
+        final int sequence = input.readInt();
+        return new OnosTimestamp(id, term, sequence);
+    }
+}