In the Riak java client, how to properly handle the case where a key/value object was not found

Question

Relatively new with Riak development here. I am using a c++ client to connect to a Riak java client that in turn connects to the Riak cluster. The c++ client serializes as a string a query using Google Protocol Buffers in the form of "GET":KEY and the Riak java client serializes the response as "OK":VALUE. How to properly handle the case that the value was not found to the database though?

This is the sample code from the Riak java client to retrieve the object from the db:

String key //Contains the actual key
Namespace ns;

byte[] retVal = null;

Location location = new Location(ns, key);

try {
  FetchValue fv;

  FetchValue.Response response = client.execute(fv);

  if (response.isNotFound()) {
    System.out.println("The key/value pair was not found");
  } else {
    RiakObject obj = response.getValue(RiakObject.class);
    retVal = obj.getValue().getValue();
  }
}
catch (...) {...}

return retVal;

}

If the object was not found, the byte[] array remains NULL

This is the sample code from the Riak java client to serialize the reply:

ByteString valueBuf = ByteString.copyFrom(value);

// Generate reply message
reply = Request.RequestMessage.newBuilder().setCommand("OK").setValue(valueBuf).build().toByteArray();

However the code throws a NullPointerException at the copyFrom line, since it tries to copy from a Null array. Is there a way to do this more cleanly?

Thanks!

score 1 · Accepted Answer · answered Apr 27 '16 at 13:53

You should check to see if value == null before attempting the copyFrom() call.

Also, you should consider using Go's ability to be called from C (cgo) rather than the Java client for integration. I put together a very, very basic demonstration of doing that here.

In the Riak java client, how to properly handle the case where a key/value object was not found

1 Answers1