Apdu.setIncomingAndReceive() ??

Question

In order to receive the whole apdu commmand send to the card, we must implement apdu.setIncomingAndReceive(), right? But when i receive command like [00 A0 00 00 50] for the below method indicate that i will get 0x50(80 bytes) data out. But the apdu.setIncomingAndReceive() will wait the coming 80 bytes data but there is not any data sending in as i am requesting to get 80 bytes data. As a result a i will get a error msg of time out error. So the program will stuck here and will not proceed to send the data out. How am i going to solve this? Is there and receive method to just receive the first 5 bytes of apdu command? hope u can understand my question. Thank you!
private void getData(APDU apdu)
byte[] buffer = apdu.getBuffer();
short length = apdu.setIncomingAndReceive();
Util.arrayCopyNonAtomic(Data ,0 , buffer,(short) 5, buffer[5] );
apdu.setOutgoingAndSend((short) 5, buffer[5]);
}

Answer 1

Like he said the first 5 bytes should be read into the buffer automatically when the process() method receives an APDU. If you only sent 5 bytes then you have nothing left to receive so calling setIncomingAndReceive might cause it to hang. Why you would send an APDU with a non-zero data length setting if you aren't sending data might be another question.
If you are in fact sending more data you can do something like the following:
     short bytesLeft = (short) (buffer[ISO7816.OFFSET_LC] & 0x00FF);
     short readCount = apdu.setIncomingAndReceive();
     while ( bytesLeft > 0){
          // process bytes in buffer[5] to buffer[readCount+4];
          bytesLeft -= readCount;
          readCount = apdu.receiveBytes ( ISO7816.OFFSET_CDATA );
     }