Multi-Client TCP Server /w Swing GUI

Question

Hi everybody,
i have to develop a Multi-Client TCP Server with a Swing GUI. The GUI mainly consists of a JTable which shows various trace messages from processes running on other computers. As the data needs to be filtered i�m using a custom TableModel derived from AbstractTableModel. I�m creating a new thread for every client that connects as shown in http://java.sun.com/developer/onlineTraining/Programming/BasicJava2/socket.html
Now every client thread reads data from its TCP connection and puts it into the JTable by calling the method addRow of the model. But i�m getting strange NullPointerExceptions and IndexOutOfBoundExceptions when data arrives (i�m using ArrayList in the model). These exceptions never show in a single-threaded Swing app (i�ve tested this already, so i don�t think it�s a bug in my model), so i think this is a problem with Swing�s thread unsafety? Do you have any hints on how to get away with it? Also general design tips for a Multi-Client TCP Server /w Swing GUI are greatly appreciated.
Thanks in advance!
Best regards,
Disposable_Hero

Answer 1

Of course, but i don�t think it is the model (as said before it works fine in a single thread swing app)
Here�s the code:
public class LogTableModel extends AbstractTableModel{
private Vector dataVector;
private Vector filterVector;
private String[] columnIdentifiers;
private Vector filteredbyProcess;
private Vector filteredbyLoglevel;
private boolean bEnableRefresh;
/** Creates a new instance of LogTableModel */
public LogTableModel() {
dataVector=new Vector(0);
columnIdentifiers=new String[]{"LogTime","HostName","IP","ProcessName","LogLevel","Handle","PID","TID","LogData"};
filteredbyProcess=new Vector(0);
filteredbyLoglevel=new Vector(0);
filterVector=new Vector(0);
bEnableRefresh=true;
public synchronized void enableRefresh(boolean bEnableRefresh){
this.bEnableRefresh=bEnableRefresh;
if(bEnableRefresh){
this.buildIndexListBasedOnFilter();
public synchronized void addRow(LogLine row){
dataVector.add(row);
if(bEnableRefresh)
this.buildIndexListBasedOnFilter();
public synchronized void addFilter(Filter filter){
filterVector.add(filter);
if(filter.isActive())
this.buildIndexListBasedOnFilter();
public synchronized void setFilterActive(String name,boolean active){
int i;
for(i=0;i<filterVector.size();i++)
if(((Filter)filterVector.elementAt(i)).getName().equals(name))
break;
Filter tmp=(Filter)filterVector.elementAt(i);
tmp.setActive(active);
if(active)
this.buildIndexListBasedOnFilter();
public synchronized void setFilterLoglevel(String name,int Loglevel){
int i;
for(i=0;i<filterVector.size();i++)
if(((Filter)filterVector.elementAt(i)).getName().equals(name))
break;
Filter tmp=(Filter)filterVector.elementAt(i);
tmp.setLoglevel(Loglevel);
if(tmp.isActive()==false)
this.buildIndexListBasedOnFilter();
private void buildIndexListBasedOnFilter(){
filteredbyProcess.clear();
filteredbyLoglevel.clear();
applyProcessFilter();
applyLoglevelFilter();
if(bEnableRefresh)
this.fireTableDataChanged();
private void applyProcessFilter(){
LogLine line=null;
Filter filter=null;
for(int i=0;i<dataVector.size();i++){
for(int j=0;j<filterVector.size();j++){
filter=(Filter)filterVector.elementAt(j);
line=(LogLine)dataVector.elementAt(i);
if(filter.isActive()&&(filter.getName().equals(line.getProcessName()))){
line.setHidden(true);
break;
else{
line.setHidden(false);
if(line.getHidden()!=true)
filteredbyProcess.add(new Integer(i));
private void applyLoglevelFilter(){
for(int i=0;i<filteredbyProcess.size();i++){
int index=((Integer)filteredbyProcess.get(i)).intValue();
LogLine line=(LogLine)dataVector.elementAt(index);
for(int j=0;j<filterVector.size();j++){
if(((Filter)filterVector.elementAt(j)).getName().equals(line.getProcessName())){
Filter filter=(Filter)filterVector.elementAt(j);
if((filter.getLoglevel()&line.getLogLevelAsInt())!=line.getLogLevelAsInt())
line.setHidden(true);
else
filteredbyLoglevel.add(new Integer(index));
break;
public synchronized String getColumnName(int columnIndex){
return columnIdentifiers[columnIndex];
public synchronized void clearData(){
dataVector.clear();
filteredbyProcess.clear();
filteredbyLoglevel.clear();
public synchronized int getColumnCount() {
return columnIdentifiers.length;
public synchronized int getRowCount() {
return filteredbyLoglevel.size();
public synchronized Object getValueAt(int rowIndex, int columnIndex) {
int iIndex=((Integer)filteredbyLoglevel.get(rowIndex)).intValue();// hier krachts warum???
LogLine tmp=(LogLine)dataVector.elementAt(iIndex);
switch(columnIndex){
case 0:
return tmp.getLogTime();
case 1:
return tmp.getHostName();
case 2:
return tmp.getIP();
case 3:
return tmp.getProcessName();
case 4:
return tmp.getLogLevel();
case 5:
return tmp.getHandle();
case 6:
return tmp.getProcessID();
case 7:
return tmp.getThreadID();
case 8:
return tmp.getLogData();
default:
return null;