Magtek Universal SDK Programmer's Manual page 60

Appendix C - EMV Transaction Flow
// #5
@Override
public void OnEvent(EventType eventType, IData data)
{
String message;
switch (eventType);
{
case EventType.DisplayMessage:
// Display approval message.
message = data.StringValue();
// A data size of 0 is an instruction to clear the display.
if (data.StringValue().Length == 0)
{
// Clear the UI display.
}
break;
}
}
MagTek Universal SDK| For MMS Devices | Programmer's Manual ( Java )
Page 60