import be.nikiroo.utils.Version;
+/**
+ * Base class used for the client/server basic handling.
+ * <p>
+ * It represents a single action: a client is expected to only execute one
+ * action, while a server is expected to execute one action for each client
+ * action.
+ *
+ * @author niki
+ */
abstract class ConnectAction {
private Socket s;
private boolean server;
private Version version;
+ private Version clientVersion;
private Object lock = new Object();
private BufferedReader in;
private OutputStreamWriter out;
private boolean contentToSend;
- // serverVersion = null on server (or bad clients)
- abstract public void action(Version serverVersion) throws Exception;
+ /**
+ * Method that will be called when an action is performed on either the
+ * client or server this {@link ConnectAction} represent.
+ *
+ * @param version
+ * the counter part version
+ *
+ * @throws Exception
+ * in case of I/O error
+ */
+ abstract protected void action(Version version) throws Exception;
+
+ /**
+ * Method called when we negotiate the version with the client.
+ * <p>
+ * Thus, it is only called on the server.
+ * <p>
+ * Will return the actual server version by default.
+ *
+ * @param clientVersion
+ * the client version
+ *
+ * @return the version to send to the client
+ */
+ abstract protected Version negotiateVersion(Version clientVersion);
+
+ /**
+ * Handler called when an unexpected error occurs in the code.
+ *
+ * @param e
+ * the exception that occurred
+ */
+ abstract protected void onError(Exception e);
- // server = version NULL
+ /**
+ * Create a new {@link ConnectAction}.
+ *
+ * @param s
+ * the socket to bind to
+ * @param server
+ * TRUE for a server action, FALSE for a client action (will
+ * impact the process)
+ * @param version
+ * the version of this client-or-server
+ */
protected ConnectAction(Socket s, boolean server, Version version) {
this.s = s;
this.server = server;
} else {
this.version = version;
}
+
+ clientVersion = new Version();
}
- public void connectAsync() {
- new Thread(new Runnable() {
- @Override
- public void run() {
- connect();
- }
- }).start();
+ /**
+ * The version of this client-or-server.
+ *
+ * @return the version
+ */
+ public Version getVersion() {
+ return version;
}
- // connect, do the action (sync)
+ /**
+ * Actually start the process (this is synchronous).
+ */
public void connect() {
try {
in = new BufferedReader(new InputStreamReader(s.getInputStream(),
out = new OutputStreamWriter(s.getOutputStream(), "UTF-8");
try {
if (server) {
- action(version);
+ action(clientVersion);
} else {
String v = sendString("VERSION " + version.toString());
if (v != null && v.startsWith("VERSION ")) {
}
}
- // (also, server never get anything)
- public Object send(Object data) throws IOException, NoSuchFieldException,
- NoSuchMethodException, ClassNotFoundException {
+ /**
+ * Serialise and send the given object to the counter part (and, only for
+ * client, return the deserialised answer -- the server will always receive
+ * NULL).
+ *
+ * @param data
+ * the data to send
+ *
+ * @return the answer (which can be NULL) if this action is a client, always
+ * NULL if it is a server
+ *
+ * @throws IOException
+ * in case of I/O error
+ * @throws NoSuchFieldException
+ * if the serialised data contains information about a field
+ * which does actually not exist in the class we know of
+ * @throws NoSuchMethodException
+ * if a class described in the serialised data cannot be created
+ * because it is not compatible with this code
+ * @throws ClassNotFoundException
+ * if a class described in the serialised data cannot be found
+ */
+ protected Object send(Object data) throws IOException,
+ NoSuchFieldException, NoSuchMethodException, ClassNotFoundException {
synchronized (lock) {
String rep = sendString(new Exporter().append(data).toString(true));
if (rep != null) {
}
}
- public Object flush() throws NoSuchFieldException, NoSuchMethodException,
- ClassNotFoundException, IOException, java.lang.NullPointerException {
+ /**
+ * Reserved for the server: flush the data to the client and retrieve its
+ * answer.
+ * <p>
+ * Also used internally for the client (only do something if there is
+ * contentToSend).
+ * <p>
+ * Will only flush the data if there is contentToSend.
+ *
+ * @return the deserialised answer (which can actually be NULL)
+ *
+ * @throws IOException
+ * in case of I/O error
+ * @throws NoSuchFieldException
+ * if the serialised data contains information about a field
+ * which does actually not exist in the class we know of
+ * @throws NoSuchMethodException
+ * if a class described in the serialised data cannot be created
+ * because it is not compatible with this code
+ * @throws ClassNotFoundException
+ * if a class described in the serialised data cannot be found
+ * @throws java.lang.NullPointerException
+ * if the counter part has no data to send
+ */
+ protected Object rec() throws IOException, NoSuchFieldException,
+ NoSuchMethodException, ClassNotFoundException,
+ java.lang.NullPointerException {
String str = flushString();
if (str == null) {
- throw new NullPointerException("No more data from client");
+ throw new NullPointerException("No more data available");
}
return new Importer().read(str).getValue();
}
/**
- * Handler called when the client {@link Version} is received.
+ * Send the given string to the counter part (and, only for client, return
+ * the answer -- the server will always receive NULL).
*
- * @param clientVersion
- * the client {@link Version}
- */
- protected void onClientVersionReceived(
- @SuppressWarnings("unused") Version clientVersion) {
- }
-
- /**
- * Handler called when an unexpected error occurs in the code.
+ * @param line
+ * the data to send (we will add a line feed)
*
- * @param e
- * the exception that occurred
+ * @return the answer if this action is a client (without the added line
+ * feed), NULL if it is a server
+ *
+ * @throws IOException
+ * in case of I/O error
*/
- protected void onError(@SuppressWarnings("unused") Exception e) {
- }
-
- // \n included in line, but not in rep (also, server never get anything)
- private String sendString(String line) throws IOException {
+ protected String sendString(String line) throws IOException {
synchronized (lock) {
out.write(line);
out.write("\n");
}
}
- // server can receive something even without pending content
- private String flushString() throws IOException {
+ /**
+ * Reserved for the server (externally): flush the data to the client and
+ * retrieve its answer.
+ * <p>
+ * Also used internally for the client (only do something if there is
+ * contentToSend).
+ * <p>
+ * Will only flush the data if there is contentToSend.
+ *
+ * @return the answer (which can be NULL)
+ *
+ * @throws IOException
+ * in case of I/O error
+ */
+ protected String flushString() throws IOException {
synchronized (lock) {
if (server || contentToSend) {
if (contentToSend) {
// "VERSION client-version" (VERSION 1.0.0)
Version clientVersion = new Version(
line.substring("VERSION ".length()));
- onClientVersionReceived(clientVersion);
- sendString("VERSION " + version.toString());
+ this.clientVersion = clientVersion;
+ Version v = negotiateVersion(clientVersion);
+ if (v == null) {
+ v = new Version();
+ }
+ sendString("VERSION " + v.toString());
line = in.readLine();
}
git://git.nikiroo.be / nikiroo-utils.git / blobdiff