src/be/nikiroo/utils/serial/server/ServerString.java

   1 package be.nikiroo.utils.serial.server;
   2
   3 import java.io.IOException;
   4 import java.net.Socket;
   5
   6 import be.nikiroo.utils.Version;
   7
   8 /**
   9  * This class implements a simple server that can listen for connections and
  10  * send/receive Strings.
  11  * <p>
  12  * Note: this {@link ServerString} has to be discarded after use (cannot be
  13  * started twice).
  14  *
  15  * @author niki
  16  */
  17 abstract public class ServerString extends Server {
  18         /**
  19          * Create a new server that will start listening on the network when
  20          * {@link ServerString#start()} is called.
  21          *
  22          * @param port
  23          *            the port to listen on, or 0 to assign any unallocated port
  24          *            found (which can later on be queried via
  25          *            {@link ServerString#getPort()}
  26          * @param ssl
  27          *            use a SSL connection (or not)
  28          *
  29          * @throws IOException
  30          *             in case of I/O error
  31          */
  32         public ServerString(int port, boolean ssl) throws IOException {
  33                 super(port, ssl);
  34         }
  35
  36         /**
  37          * Create a new server that will start listening on the network when
  38          * {@link ServerString#start()} is called.
  39          *
  40          * @param name
  41          *            the server name (only used for debug info and traces)
  42          * @param port
  43          *            the port to listen on
  44          * @param ssl
  45          *            use a SSL connection (or not)
  46          *
  47          * @throws IOException
  48          *             in case of I/O error
  49          */
  50         public ServerString(String name, int port, boolean ssl) throws IOException {
  51                 super(name, port, ssl);
  52         }
  53
  54         @Override
  55         protected ConnectActionServer createConnectActionServer(Socket s) {
  56                 return new ConnectActionServerString(s) {
  57                         @Override
  58                         public void action(Version clientVersion) throws Exception {
  59                                 try {
  60                                         for (String data = rec(); data != null; data = rec()) {
  61                                                 String rep = null;
  62                                                 try {
  63                                                         rep = onRequest(this, clientVersion, data);
  64                                                 } catch (Exception e) {
  65                                                         onError(e);
  66                                                 }
  67
  68                                                 if (rep == null) {
  69                                                         rep = "";
  70                                                 }
  71
  72                                                 send(rep);
  73                                         }
  74                                 } catch (NullPointerException e) {
  75                                         // Client has no data any more, we quit
  76                                         getTraceHandler()
  77                                                         .trace(getName()
  78                                                                         + ": client has data no more, stopping connection");
  79                                 }
  80                         }
  81
  82                         @Override
  83                         public void connect() {
  84                                 try {
  85                                         super.connect();
  86                                 } finally {
  87                                         count(-1);
  88                                 }
  89                         }
  90                 };
  91         }
  92
  93         /**
  94          * This is the method that is called on each client request.
  95          * <p>
  96          * You are expected to react to it and return an answer (NULL will be
  97          * converted to an empty {@link String}).
  98          *
  99          * @param action
 100          *            the client action
 101          * @param clientVersion
 102          *            the client version
 103          * @param data
 104          *            the data sent by the client
 105          *
 106          * @return the answer to return to the client
 107          *
 108          * @throws Exception
 109          *             in case of an exception, the error will only be logged
 110          */
 111         abstract protected String onRequest(ConnectActionServerString action,
 112                         Version clientVersion, String data) throws Exception;
 113 }