Check key/value size to mimic RAMCloud limit.

Note: In RAMCloud spec, it is defined as Key <= 64KB, Value Blob <= 1MB.

Change-Id: I3924f50f27353238d7d5859bb2d644a7968955c9
diff --git a/src/main/java/net/onrc/onos/core/datastore/DataStoreClient.java b/src/main/java/net/onrc/onos/core/datastore/DataStoreClient.java
index b5c1ae7..1215770 100644
--- a/src/main/java/net/onrc/onos/core/datastore/DataStoreClient.java
+++ b/src/main/java/net/onrc/onos/core/datastore/DataStoreClient.java
@@ -5,6 +5,10 @@
 
 // This class probably need to be a service
 public final class DataStoreClient {
+
+    public static final int MAX_KEY_BYTES = 64 * 1024;
+    public static final int MAX_VALUE_BYTES = 1024 * 1024;
+
     private static final String BACKEND = System.getProperty("net.onrc.onos.core.datastore.backend", "hazelcast");
 
     // Suppresses default constructor, ensuring non-instantiability.