Thread safe display of JTable
Hi all,
I have a JTree, which has JTable as its node.
Each JTable has some children that will be displayed on expanding a node.
When user expands a node, next sibling node of that ( a JTable again) will get header.I am programmatically adding header to the table.To display properly I am performing 2 steps:
1) adding header to the table
2) Increasing the size of the table by some new dimension for making it to show with header.
At run time when I expand the tree is not repainting properly.When I expands any node the next sibling(a JTable) is only appearing with its old size but showing header. After performing some more events it is appearing properly to the user.
Is this because of improper threads?
pls provide a solution to this problem.
thanks in advance
amar
Hi sabre150 ,
thanx for responding.
It took some time for me to prepare a sample.
Here I am pasting sample similar to my application.
I hope you can better understand my problem by running this sample.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.tree.*;
import java.util.*;
import javax.swing.event.*;
public class TestJTreePanel extends JPanel {
JScrollPane jScrollPane1 = new JScrollPane();
JTree jTree1;
TradeAllocTableNodePanel treenodePanel = new TradeAllocTableNodePanel();
TradeAllocTableNodePanel treenodePanel2 = new TradeAllocTableNodePanel();
TradeAllocRcptDelTableNodePanel childtreenodePanel = new TradeAllocRcptDelTableNodePanel();
GridBagLayout gridBagLayout1 = new GridBagLayout();
public TestJTreePanel() {
this.setBorder(null);
try {
DefaultMutableTreeNode topNode = new DefaultMutableTreeNode("Allocations", true);
treenodePanel.getTable().getTableHeader().setPreferredSize(new Dimension(897,20));
DefaultMutableTreeNode childTradeAllocNode1 = new DefaultMutableTreeNode(treenodePanel, true);
((TradeAllocTableNodePanel)childTradeAllocNode1.getUserObject()).setUserPreferedSize(new Dimension(897, 40));
DefaultMutableTreeNode childRcptDelNode1 = new DefaultMutableTreeNode(childtreenodePanel);
jScrollPane1.setBorder(null);
this.setAlignmentX((float) 0.5);
this.setAlignmentY((float) 0.5);
this.setActionMap(null);
childTradeAllocNode1.add(childRcptDelNode1);
DefaultMutableTreeNode childTradeAllocNode2 = new DefaultMutableTreeNode(new TradeAllocTableNodePanel(), true);
DefaultMutableTreeNode childRcptDelNode2 = new DefaultMutableTreeNode(childtreenodePanel);
childTradeAllocNode2.add(childRcptDelNode2);
DefaultMutableTreeNode childTradeAllocNode3 = new DefaultMutableTreeNode(new TradeAllocTableNodePanel(), true);
DefaultMutableTreeNode childRcptDelNode3 = new DefaultMutableTreeNode(childtreenodePanel);
childTradeAllocNode3.add(childRcptDelNode3);
DefaultMutableTreeNode childTradeAllocNode4 = new DefaultMutableTreeNode(new TradeAllocTableNodePanel(), true);
DefaultMutableTreeNode childRcptDelNode4 = new DefaultMutableTreeNode(childtreenodePanel);
childTradeAllocNode4.add(childRcptDelNode4);
topNode.add(childTradeAllocNode1);
topNode.add(childTradeAllocNode2);
topNode.add(childTradeAllocNode3);
topNode.add(childTradeAllocNode4);
jTree1 = new JTree(topNode);
jTree1.setCellRenderer(new TradeAllocTreeCellRenderer());
jTree1.setRootVisible(false);
jTree1.setShowsRootHandles(true);
jTree1.addTreeExpansionListener(new TreeExpansionListener()
public void treeExpanded(TreeExpansionEvent e)
//TreePath of expanded node
TreePath pathObject = e.getPath();
DefaultMutableTreeNode node = (DefaultMutableTreeNode)pathObject.getLastPathComponent();
if (node == null) return;
final DefaultMutableTreeNode siblingNode = node.getNextSibling();
if (siblingNode == null) return;
if(siblingNode.getLevel()==1)
((TradeAllocTableNodePanel)siblingNode.getUserObject()).getTable().getTableHeader().setPreferredSize(new Dimension(897, 20));
((TradeAllocTableNodePanel)siblingNode.getUserObject()).setUserPreferedSize(new Dimension(897, 40));
((DefaultTreeModel)jTree1.getModel()).nodeChanged(siblingNode);
jTree1.treeDidChange();
public void treeCollapsed(TreeExpansionEvent e)
TreePath pathObject = e.getPath();
DefaultMutableTreeNode node = (DefaultMutableTreeNode)pathObject.getLastPathComponent();
if (node == null) return;
DefaultMutableTreeNode siblingNode = node.getNextSibling();
if (siblingNode == null) return;
if(siblingNode.getLevel()==1)
((TradeAllocTableNodePanel)siblingNode.getUserObject()).getTable().getTableHeader().setPreferredSize(new Dimension(0,0));
((TradeAllocTableNodePanel)siblingNode.getUserObject()).setUserPreferedSize(new Dimension(897, 20));
((DefaultTreeModel)jTree1.getModel()).nodeChanged(siblingNode);
jTree1.treeDidChange();
this.setLayout(gridBagLayout1);
this.add(jScrollPane1, new GridBagConstraints(0, 1, 1, 1, 1.0, 1.0
,GridBagConstraints.CENTER, GridBagConstraints.BOTH, new Insets(0, 0, 0, 0), 397, -48));
jScrollPane1.getViewport().add(jTree1, null);
catch(Exception ex) {
ex.printStackTrace();
public static void main(String args[])
TestJTreePanel test=new TestJTreePanel();
JFrame frame=new JFrame();
frame.getContentPane().add(test);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(new Dimension(900,500));
frame.setVisible(true);
public static class ResultTreeCellRenderer extends DefaultTreeCellRenderer
public Component getTreeCellRendererComponent(JTree t, Object value,boolean s, boolean o,boolean l, int r, boolean h)
if (value instanceof DefaultMutableTreeNode)
DefaultMutableTreeNode node = (DefaultMutableTreeNode) value;
if (node.getUserObject() instanceof TradeAllocTableNodePanel)
return new JScrollPane((TradeAllocTableNodePanel) node.getUserObject());
return super.getTreeCellRendererComponent(t, value, s, o, l, r, h);
//*************Table code**********************
public class TradeAllocTableNodePanel extends JPanel {
JScrollPane jScrollPane1 = new JScrollPane();
public JTable jTable1 = new JTable();
BorderLayout borderLayout1 = new BorderLayout();
public TradeAllocTableNodePanel() {
this.setBorder(null);
try {
Object[] [] rowData = {
{ "Allocated", "6789", "NO6-10;NO6-12", "GLENCOR E L", "5340", "12/01/20", "12/15/20", "", "", "$", "C", "FA" }
String[] columnNames = { "AllocStatus", "AllocNumb", "Cmdty", "Cpty", "Alloc", "MinForm", "MaxToD", "MOTType", "MOT", "ShowCosts", "Comments", "FullyActualize" };
jTable1 = new JTable(rowData, columnNames);
jTable1.getTableHeader().setPreferredSize(new Dimension(0,0));
setUserPreferedSize(new Dimension(897, 20));
this.setLayout(borderLayout1);
jScrollPane1.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
jScrollPane1.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
jScrollPane1.setAutoscrolls(false);
this.add(jScrollPane1, BorderLayout.CENTER);
jScrollPane1.getViewport().add(jTable1, null);
jTable1.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS);
catch(Exception ex) {
ex.printStackTrace();
public void setUserPreferedSize(Dimension newDimension){
if(newDimension != null){
super.setPreferredSize(newDimension);
public JTable getTable() {
return jTable1;
public class TradeAllocTreeCellRenderer extends DefaultTreeCellRenderer {
public TradeAllocTreeCellRenderer() {
super();
updateUI();
public Component getTreeCellRendererComponent(JTree tree, Object value,
boolean selected,
boolean expanded, boolean leaf,
int row, boolean hasFocus) {
super.getTreeCellRendererComponent(tree, value, selected, expanded, leaf,
row, hasFocus);
if (value instanceof DefaultMutableTreeNode) {
DefaultMutableTreeNode deftreenode = (DefaultMutableTreeNode) value;
Object userObj = deftreenode.getUserObject();
if (userObj instanceof JPanel) {
JPanel pnlLeaf = (JPanel) userObj;
tree.setRowHeight(0);
pnlLeaf.repaint();
pnlLeaf.invalidate();
pnlLeaf.validate();
return ((JPanel)pnlLeaf);
return super.getTreeCellRendererComponent(tree, value, selected, expanded, leaf, row, hasFocus);
public Dimension getPreferredSize() {
Dimension retDimension = super.getPreferredSize();
if(retDimension != null)
retDimension = new Dimension(retDimension.width+3,
retDimension.height);
return retDimension;
public class TradeAllocRcptDelTableNodePanel extends JPanel {
JScrollPane jScrollPane1 = new JScrollPane();
JTable jTable1;
BorderLayout borderLayout1 = new BorderLayout();
public TradeAllocRcptDelTableNodePanel() {
try {
jbInit();
catch(Exception ex) {
ex.printStackTrace();
void jbInit() throws Exception {
Object[] [] rowData = {
{ "REC", "GLENCOR E L", "87063/3/1/168673", "NO6-10", "12/02/2", "12/15/2", "12/02/2", "5430", "BBL", "0", "A", "true", "", "", "", "" },
{ "DEL", "GLENCOR E L", "87063/3/1/168673", "NO6-10", "12/02/2", "12/15/2", "12/02/2", "5430", "BBL", "0", "B", "true", "", "", "", "" }
String[] columnNames = { "REC_DEL", "Cpty", "Trade_Port", "Cmdty", "NomFrom", "NomTo", "ETA", "NomQTY", "NomUOM", "ActualQTY", "A", "P", "FA", "ActualDT", "Credit", "Insp_Agent" };
jTable1 = new JTable(rowData, columnNames);
this.setLayout(borderLayout1);
jScrollPane1.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
jScrollPane1.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_NEVER);
jScrollPane1.setAutoscrolls(false);
jTable1.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS);
//upto here on 080404
jScrollPane1.getViewport().add(jTable1, null);
this.add(jScrollPane1, BorderLayout.CENTER);
this.setPreferredSize(new Dimension(879, 56));
thanx
amar
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Dirigo Multimedia, Inc.
[email protected]Zac Lam wrote:
The Memory Suite does pull from a specific memory pool that is set based on the user-specified Memory settings in the Preferences. If you use standard OS calls, then you could end up allocating memory beyond the user-specified settings, whereas using the Memory Suite will help you stick to the Memory settings in the Preferences.
When you get back NULL when allocating memory, are you hitting the upper boundaries of your memory usage? Are you getting any error code returned from the function calls themselves?
I am not hitting the upper memory bounds - I have several customers that have 10's of Gb free.
There is no error return code from the ->NewPtr() call.
PrMemoryPtr (*NewPtr)(csSDK_uint32 byteCount);
A NULL pointer is how you detect a problem.
Note that changing the size of the ->ReserveMemory() doesn't seem to make any difference as to whether you'll get a memory ptr or NULL back.
btw my NewPtr size is either
W x H x sizeof(PrPixelFormat_YUVA4444_32f)
W x H x sizeof(PrPixelFormat_YUVA4444_8u)
and happens concurrently on #cpu's threads (eg 16 to 32 instances at once is pretty common).
The more processing power that the nVidia card has seems to make it fall over faster.
eg I don't see it at all on a GTS 250 but do on a GTX 480, Quadro 4000 & 5000 and GTX 660
I think there is a threading issue and an issue with the Memory Suite's pool and how it interacts with the CUDA memory pool. - note that CUDA sets RESERVED (aka locked) memory which can easily cause a fragmenting problem if you're not using the OS memory handler. -
Is the Memory Suite thread safe?
Hi all,
Is the memory suite thread safe (at least when used from the Exporter context)?
I ask because I have many threads getting and freeing memory and I've found that I get back null sometimes. This, I suspect, is the problem that's all the talk in the user forum with CS6 crashing with CUDA enabled. I'm starting to suspect that there is a memory management problem when there is also a lot of memory allocation and freeing going on by the CUDA driver. It seems that the faster the nVidia card the more likely it is to crash. That would suggest the CUDA driver (ie the code that manages the scheduling of the CUDA kernels) is in some way coupled to the memory use by Adobe or by Windows alloc|free too.
I replaced the memory functions with _aligned_malloc|free and it seems far more reliable. Maybe it's because the OS malloc|free are thread safe or maybe it's because it's pulling from a different pool of memory (vs the Memory Suite's pool or the CUDA pool)
comments?
EdwardZac Lam wrote:
The Memory Suite does pull from a specific memory pool that is set based on the user-specified Memory settings in the Preferences. If you use standard OS calls, then you could end up allocating memory beyond the user-specified settings, whereas using the Memory Suite will help you stick to the Memory settings in the Preferences.
When you get back NULL when allocating memory, are you hitting the upper boundaries of your memory usage? Are you getting any error code returned from the function calls themselves?
I am not hitting the upper memory bounds - I have several customers that have 10's of Gb free.
There is no error return code from the ->NewPtr() call.
PrMemoryPtr (*NewPtr)(csSDK_uint32 byteCount);
A NULL pointer is how you detect a problem.
Note that changing the size of the ->ReserveMemory() doesn't seem to make any difference as to whether you'll get a memory ptr or NULL back.
btw my NewPtr size is either
W x H x sizeof(PrPixelFormat_YUVA4444_32f)
W x H x sizeof(PrPixelFormat_YUVA4444_8u)
and happens concurrently on #cpu's threads (eg 16 to 32 instances at once is pretty common).
The more processing power that the nVidia card has seems to make it fall over faster.
eg I don't see it at all on a GTS 250 but do on a GTX 480, Quadro 4000 & 5000 and GTX 660
I think there is a threading issue and an issue with the Memory Suite's pool and how it interacts with the CUDA memory pool. - note that CUDA sets RESERVED (aka locked) memory which can easily cause a fragmenting problem if you're not using the OS memory handler. -
Can use the same thread safe variable in the different processes?
Hello,
Can use the same thread safe variable in the different processes? my application has a log file used to record some event, the log file will be accessed by the different process, is there any synchronous method to access the log file with CVI ?
DavidLimiting concurrent access to shared resources can be better obtained by using locks: once created, the lock can be get by one requester at a time by calling CmtGetLock, the other being blocked in the same call until the lock is free. If you do not want to lock a process you can use CmtTryToGtLock instead.
Don't forget to discard locks when you have finished using them or at program end.
Alternatively you can PostDeferredCall a unique function (executed in the main thread) to write the log passing the apprpriate data to it.
Proud to use LW/CVI from 3.1 on.
My contributions to the Developer Zone Community
If I have helped you, why not giving me a kudos? -
Native library NOT thread safe - how to use it via JNI?
Hello,
has anybody ever tried to use a native library from JNI, when the library is not thread safe?
The library (Windows DLL) was up to now used in an MFC App and thus was only used by one user - that meant one thread - at a time.
Now we would like to use the library like a "server": many Java clients connect the same time to the library via JNI. That would mean each client makes its calls to the library in its own thread. Because the library is not thread safe, this would cause problems.
Now we discussed to load the library several times - separately for each client (for each thread).
Is this possible at all? How can we do that?
And do you think we can solve the problem in this way?
Are there other ways to use the library, though it is not thread safe?
Any ideas welcome.
Thanks for any contributions to the discussion, Ina(1)
has anybody ever tried to use a native library from
JNI, when the library (Windows DLL) is not thread safe?
Now we want many Java clients.
That would mean each client makes its calls
to the library in its own thread. Because the library
is not thread safe, this would cause problems.Right. And therefore you have to encapsulate the DLL behind a properly synchronized interface class.
Now the details of how you have to do that depends: (a) does the DLL contain state information other than TLS? (b) do you know which methods are not thread-safe?
Depending on (a), (b) two extremes are both possible:
One extreme would be to get an instance of the interface to the DLL from a factory method you'll have to write, where the factory method will block until it can give you "the DLL". Every client thread would obtain "the DLL", then use it, then release it. That would make the whole thing a "client-driven" "dedicated" server. If a client forgets to release the DLL, everybody else is going to be locked out. :-(
The other extreme would be just to mirror the DLL methods, and mark the relevant ones as synchronized. That should be doable if (a) is false, and (b) is true.
(2)
Now we discussed to load the library several times -
separately for each client (for each thread).
Is this possible at all? How can we do that?
And do you think we can solve the problem in this
way?The DLL is going to be mapped into the process address space on first usage. More Java threads just means adding more references to the same DLL instance.
That would not result in thread-safe behavior. -
Is Persistence context thread safe? nop
In my code, i have a servlet , 2 stateless session beans:
in the servlet, i use jndi to find a stateless bean (A) and invoke a method methodA in A:
(Stateless bean A):
@EJB
StatelessBeanB beanB;
methodA(obj) {
beanB.save(obj);
(Stateless bean B, where container inject a persistence context):
@PersistenceContext private EntityManager em;
save(obj) {
em.persist(obj);
it is said entity manager is not thread safe, so it should not be an instance variable. But in the code above, the variable "em" is an instance variable of stateless bean B, Does it make sense to put it there using pc annotation? is it then thread safe when it is injected (manager) by container?
since i think B is a stateless session bean, so each request will share the instance variable of B class which is not a thread safe way.
So , could you please give me any guide on this problem? make me clear.
any is appreciated. thank you
and what if i change stateless bean B to
(Stateless bean B, where container inject a persistence context):
@PersistenceUnit private EntityManagerFactory emf;
save(obj) {
em = emf.creatEntityManager()
//begin tran
em.persist(obj);
// commit tran
//close em
the problem is i have several stateless beans like B, if each one has a emf injected, is there any problem ?Hi Jacky,
An EntityManager object is not thread-safe. However, that's not a problem when accessing an EntityManager from EJB bean instance state. The EJB container guarantees that no more than one thread has access to a particular bean instance at any given time. In the case of stateless session beans, the container uses as many distinct bean instances as there are concurrent requests.
Storing an EntityManager object in servlet instance state would be a problem, since in the servlet programming model any number of concurrent threads share the same servlet instance.
--ken -
Web service client proxy thread safe?
Is the jax-ws web service client proxy and port objects thread safe in Weblogic 10.3.4?
Been searching through the docs but can't find any info on this.I have searched and it seems that with cxf it's safe to do something like this.
Nobody knows if this is safe using metro? -
Thread-safe design pattern for encapsulating Collections?
Hi,
This must be a common problem, but I just can't get my head around it.
Bascially I'm reading in data from a process, and creating/updating data structuers from this data. I've got a whloe bunch of APTProperty objects (each with a name/value) stored in a sychronized HashMap encapsulated by a class called APTProperties. It has methods such as:
addProperty(APTProperty) // puts to hashmap
getProperty(String name) // retreives from hashmap
I also want clients to be able to iterate through all the APTProperties, in a thread safe manner . ie. they aren't responsible for sychronizing on the Map before getting the iterator. (See Collections.synchronizedMap() API docs).
Is there any way of doing this?
Or should I just have a method called
Iterator propertyIterator() which returns the corresponding iterator of the HashMap (but then I can't really make it thread safe).
I'd rather not make the internal HashMap visible to calling clients, if possible, 'cause I don't want people tinkering with it, if you know what I mean.
Hope this makes sense.
KeithIn that case, I think you need to provide your own locking mechanism.
public class APTProperties {
the add, get and remove methods call lock(), executes its own logic, then call unlock()
//your locking mechanism
private Thread owner; //dont need to be volatile due to synchronized access
public synchronized void lock() {
while(owner != null) {
wait();
th = Thread.currentThread();
public synzhronized void unlock() {
if(owner == currentThread()){
owner = null;
notifyAll();
}else {
throw new IllegalMonitorStateException("Thread: "+ Thread.currentThread() + "does not own the lock");
Now you dont gain a lot from this code, since a client has to use it as
objAPTProperties.lock();
Iterator ite = objAPTProperties.propertyIterator();
... do whatever needed
objAPTProperties.unlock();
But if you know how the iterator will be used, you can make the client unaware of the locking mechanism. Lets say, your clients will always go upto the end thru the iterator. In that case, you can use a decorator iterator to handle the locking
public class APTProperties {
public Iterator getThreadSafePropertyIterator() {
private class ThreadSafeIterator implements Iterator {
private iterator itr;
private boolean locked;
private boolean doneIterating;
public ThreadSafeIterator(Iterator itr){
this.itr = itr;
public boolean hasNext() {
return doneIterating ? false : itr.hasNext();
public Object next() {
lockAsNecessary();
Object obj = itr.next();
unlockAsNecessary();
return obj;
public void remove() {
lockAsNecessary();
itr.remove();
unlockAsNecessary();
private void lockAsNecessary() {
if(!locked) {
lock();
locked = true;
private void unlcokAsNecessary() {
if(!hasNext()) {
unlock();
doneIterating = true;
}//APTProperties ends
The code is right out of my head, so it may have some logic problem, but the basic idea should work.
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