Java serialization. Field changes value

[Siobhan Chom]

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I have the following problem. I can set the transaction state to be either "start, end or ongoing". I set this, then serialise my Transaction object over to the server, who retrieves it. Works like a charm the first time (when the transaction is in start mode), but then when I resend the object, this time in "ongoing" mode, the server continues to see it in "start" mode. I've tested the code at the line before the serialization, and the line after the deserialization, and this is definitely where the problem is. Any help would be very much appreciated. The relevant code snippets are as follows:

serialization

        if ((query instanceof Transaction) && !(trx.getTransactionState()==Consts.trx_start)) System.out.println("Not start");
        oos.writeObject(query);
        oos.flush();

deserialization

    while (true) {
                Object statement = null;

                try {

                    statement = ois.readObject();
                    if ((statement instanceof Transaction) && !(((Transaction) statement).getTransactionState()==Consts.trx_start)) System.out.println("Not start 2");
                    handle_statement(statement, socket);
                } catch (IOException e) {

and the Transaction class:

    public class Transaction extends Statement{

/**
 * 
 */
private static final long serialVersionUID = -2284996855537430822L;
Statement statement_list;
int trx_state; 


/**
 * 
 */
public Transaction() {
    trx_state = Consts.trx_start;; 
}

/**
 * @param statement
 */
public void setStatement(Statement statement ) { 
    statement_list = statement; 
} 


public void setTransactionState(int state) {
        trx_state = state; 
}

public int getTransactionState() {
    return trx_state; 
}
/**
 * @return
 */
public Statement getStatement() {
    return statement_list;
}

[Jeff Verdegan]

If you resend the same object over the same stream, the object itself is not sent, just a reference to the original one sent (which obviously will still have the original value). This is done to save bandwidth on network serialization and make files of serialized objects smaller. If you want the stream to actually resend the object, there's a method to make it forget what it has sent so far. I think it's reset(), but check the docs to be sure.

[Siobhan Chom]

Genius thanks! I thought using flush would be enough. but reset works very well

[Jeff Verdegan]

Siobhan Chom wrote:Genius thanks! I thought using flush would be enough. but reset works very well

Calling flush() just tells the stream to send any data it's buffering to the other end.

Glad you got it sorted out! Welcome to the Ranch!