question

Root cause

The Java driver can't serialise the LocalDateTime object in your code and so it throws the InvalidTypeException.

Workaround

I apologise that it's not clear to me from your code what class the LocalDateTime object is but if it's Joda Time, it might be possible for you to get around it by converting it to Java Date like this:

    LocalDateTime.now().toDate()

It isn't elegant but may work in your situation.

Custom codecs

The correct way of handling this is to map the CQL timestamp to a Joda class using a custom codec.

Here's an example implementation of a custom DateTimeCodec:

public class DateTimeCodec extends TypeCodec<DateTime> {
  public DateTimeCodec() {
    super(DataType.timestamp(), DateTime.class);
  }

  @Override
  public DateTime parse(String value) {
    if (value == null || value.equals("NULL"))
      return null;

    try {
      return DateTime.parse(value);
    } catch (IllegalArgumentException iae) {
      throw new InvalidTypeException("Could not parse format: " + value, iae);
    }
  }

  @Override
  public String format(DateTime value) {
    if (value == null)
      return "NULL";

    return Long.toString(value.getMillis());
  }

  @Override
  public ByteBuffer serialize(DateTime value, ProtocolVersion protocolVersion) {
    return value == null ? null : BigintCodec.instance.serializeNoBoxing(value.getMillis(), protocolVersion);
  }

  @Override
  public DateTime deserialize(ByteBuffer bytes, ProtocolVersion protocolVersion) {
    return bytes == null || bytes.remaining() == 0 ? null: new DateTime(BigintCodec.instance.deserializeNoBoxing(bytes, protocolVersion));
  }
}

The full example is available on https://github.com/o19s/JodaTimeCodecs.

Credits

The example is compliments of Christopher Bradford (@bradfordcp).

For more information, see the Java driver Custom Codecs page. Cheers!