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Message:

data reciever thread gets interrupted by AWTThread

Posted by shekar on July 19, 2001 at 11:17 AM

my app starts a reciever thread which indefinitely recieves a data/message from a server [written in c]on UDP port. these messages are split into String array[10] and they are to be added as a new row of a JTable through a TableModel. But reciever thread shall never get interrupted at any cost by AWTThread that adds a row to a Table. I want the reciever thread to just recieve message and let the main GUI that houses the JTable to handle dispathing of event lets say setTableRow(String row[]). Am afraid if i implement a producer/consumer pair, it would lock the reciever Thread which is not acceptable as the data is coming at a speed of 10 to 15 records per second.
I think EventDelegation model would offer a better design approach. But i have no knowledge of how to implement delegation model for this scenario.
existing problem: while new rows are added reciever thread missing some of packets. i suspect the AWTThread is taking more time..interrupting recieverThread.

// Following code does not contain the working module.
// this is the look of MY App's design.
// the server sends data at apretty high speed about 10 to 15 records per second
// My reciever thread is a kind of selfish thread, doesnt sleep at all.
// is there anything wrong in design approach for dispatching the event on MAinGUI Frame
// I want reciever thread to just recieve the data and let the frame handle
// processing of events for displaying the rows

class DataReciever{
JFrame frame
// gets instantiated by mainGUI
public void dataReciver(String host,int port,JFrame frm)
{
frame = frm;
// basic connection to the reciever
// register the port on which reciever listens
//set up Datagram socket
// start the RecieverThread
}

// inner reciver Thread class
class reciever extendsThread
{
public void run()
{
byte[] buf = new byte[1024];

DatagramPacket packet = new DatagramPacket(buf, buf.length);

sock.receive(packet); // block

ByteArrayInputStream bstream =
new ByteArrayInputStream(packet, 1,
packet.getLength()-1);

parseMessage(bstream);
}

parseMessage(ByteArrayInputStream stream)
{
//message parsing..
String row = new String[9];
row = message;

frame.callDispatchEvent(row);
}
};
public void disconnect(){}
}
/***************************************************************/

class mainUI
{

mainGUI()
{

enableEvents(UserEvent.USER_EVENT_MASK);

addUserEventListener(new UserEventAdapter()
{
public void showEvent(UserEvent ue)
{
// method of Table class to set add rows to the TableModel
Table.setRows((String [])ue.getObject());
}
});

table = new Table();
// set the column title
table.setColumns(Columns);
JScrollPane tableScrollPane = new JScrollPane(table);
// basic frame window
JFrame frame = new JFrame("");
// handle closing event
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e)
{
disconnect();//disconnect from the reciever
System.exit(0);
}
});

frame.getContentPane().add(tableScrollPane);//add table
// show frame
// call DataReciever to run reciever Thread with (server name, port number, frame)
}
public synchronized void addUserEventListener(UserEventListener l)
{
userEventListener = UserEventMulticaster.add(userEventListener, l);
}

public synchronized void removeUserEventListener(UserEventListener l) {
userEventListener = UserEventMulticaster.remove(userEventListener, l);
}

public void processEvent(AWTEvent e)
{
if(e instanceof UserEvent)
{
if (userEventListener != null)
{
if(e.getID() == UserEvent.SHOW_EVENT)
{
userEventListener.showEvent((UserEvent)e);
}
return;
}
}
super.processEvent(e);
}
public void callDispatchEvent(String row[])
{
UserEvent ue = new UserEvent(this,UserEvent.SHOW_EVENT,row);

frame.dispatchEvent(ue);
}
}
/***************************************************************/

public class UserEvent extends AWTEvent {

public static final int SHOW_EVENT = RESERVED_ID_MAX+1;
public static final int USER_EVENT_MASK = 0x10000;

Object sObject[] = new Object[9];

public UserEvent(Object source,int id,Object s[]){
super(source,id);
sObject =s;
}

public Object[] getObject(){
return sObject;
}

public String paramString() {
String typeStr;
switch(id) {
case SHOW_EVENT:
typeStr = "SHOW_EVENT";
//typeStr += (",Record = "+(String)sObject);
break;
default:
typeStr = "unknown type";
}
return typeStr;
}

}

/***************************************************************/

public interface UserEventListener extends EventListener {
public void showEvent(UserEvent e);
}
/***************************************************************/

public abstract class UserEventAdapter implements UserEventListener {
public void showEvent(UserEvent ue){}

}
/***************************************************************/

public class UserEventMulticaster extends AWTEventMulticaster implements UserEventListener {

protected UserEventMulticaster(EventListener a, EventListener b) {
super(a,b);
}

public void showEvent(UserEvent e) {
((UserEventListener)a).showEvent(e);
((UserEventListener)b).showEvent(e);
}

public static UserEventListener add(UserEventListener a, UserEventListener b) {
return (UserEventListener)addInternal(a, b);
}

public static UserEventListener remove(UserEventListener l, UserEventListener oldl) {
return (UserEventListener) removeInternal(l, oldl);
}

}
/***************************************************************/

class Table
{

protected static JTable m_table;
protected static TableModel m_data;

public Table()
{
// initalize TableModel and JTable
}
public static void setColumns(String columns[])
{
// set up column header
}
public static void setRows(final String rows[])
{
m_data.setTableRows(rows);

int temp = m_data.getColumnCount();

for(k = 0;k {
model.getColumn(k).setCellRenderer(new TabIconRenderer());
m_table.tableChanged(new TableModelEvent(m_data));

}
}
public JTable getTable()
{

return m_table;
}
}

/***************************************************************/

class TableModel extends DefaultTableModel
{
int rowCount;

public static Vector m_columns;

protected static Vector m_vector;

public static int m_columnsCount = ( m_columns==null) ? 0 :
m_columns.size();

TableModel()
{
m_columns = new Vector();// coulmns
m_vector = new Vector();// rows

m_vector.removeAllElements();
m_columns.removeAllElements();

m_columnsCount = ( m_columns==null) ? 0 : m_columns.size();

}

public void setColumn(){}//

public void setTableRows(String rows[])
{
m_vector.add(0,new RowObject(rows));
}

public Object getValueAt(col,row)
{
return value;//
}
}

/***************************************************************/

public class TabIconRenderer extends DefaultTableCellRenderer
{

// this render the icons and backGound color for table row depending on certain values in row

}
/******************************END*********************************/
Any suggestion with code snippet wud be of greate help.
thanks in advance.
Shekar.