public boolean isAlive(){
  if (hasSentData) {
    if (System.currentTimeMillis() - lastSendTime < TIMEOUT)     return true;
    return hasReceivedData && lastReceiveTime > lastSendTime;
  }
  return true;
}

public boolean isAlive ( ) { if ( hasSentData ) { if ( System . currentTimeMillis ( ) - lastSendTime < TIMEOUT ) return true ; return hasReceivedData && lastReceiveTime > lastSendTime ; } return true ; }
calculates whether this peer is alive : the peer is alive when the peer hasn ' t send data yet , or when data is received within the timeout after sending data .
