Question

I’m trying to implement such a protocol:

Client side:
 1) client sends     command (String)
 2) client sends     object
 3) client receives  object or data   [depends on command]
Server side:
 1) server reads     command (String)
 2) server receives  object           [type depends on command]
 3) server sends     object or data   [depends on command]

On client side, I’m doing something like this (program blocks on line, marked with “!!!”):

/** Retrieves required wrapper streams */
private void getSocketStreams() {
    try {
        inputStream         = new DataInputStream(
                                    connection.getInputStream());

        /* !!! here is a problem: can I do next line's stuff? */
        inputObjectStream   = new ObjectInputStream(
                                    connection.getInputStream());

        outputWriter        = new BufferedWriter(
                                new OutputStreamWriter(
                                    connection.getOutputStream()));
        outputObjectStream  = new ObjectOutputStream(
                                    connection.getOutputStream());
    } catch (IOException e) {
        e.printStackTrace();
    }
}

/** "put" command processor */
private int processCmdPut(OrderInfo orderInfo) {

    /* Send command to peer */
    try {
        outputWriter.write("put");
        outputWriter.newLine();
        outputWriter.flush();
    } catch (IOException e) {
        e.printStackTrace();
    }

    /* Send inserted object to peer */
    sendObject(orderInfo);

    /* Get from peer inserted info id */
    int id = -1;
    try {
        id = inputStream.readInt();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return id;
}


/**
 * Sends object to peer.
 * @param obj object to send.
 */
public void sendObject(Object obj){
    try {
        outputObjectStream.writeObject(obj);
        outputObjectStream.flush();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

Server’s side actions a mirrored client’s.

The question about line, marked with “!!!”: is it possible to wrap socket’s byte stream
with two different high-lever streams and read/write into them by turns (one by one)?
Am I wrong? There is my error or misunderstanding?

Answer 1

Buffering tends to make using different decorators chains difficult at best. You really don’t want to be mixing text and binary data on the same stream. I suggest writing text in the same format you are using for the binary data.