Multi-Thread Messaging

I'm sure that this question is old hat for the experienced multi-threaded programmers.
I'm trying to design a server software system, and one of the requirements that I have is that one of the clients (or even the server itself) should be able to pass messages to all of the connected clients.
I plan to have a persistent (for the lifetime of the connection) thread for each client in order to persist the user authority information. I'd like to utilize this same set of threads, to send messages to, and receive messages from the clients.
So... Two questions:
Is this an appropriate way of doing this, or should I setup a different server to manage messagin?
If this is appropriate; how do I pass a message from one thread to all other threads in the program?
Thank you for taking the time to read and consider my questions.
IsomerX

IsomerX wrote:
Ok, I can see that.
It still leaves the question of how to pass the information from one thread to another.The server should know should how many clients that are connected and post a message on each queue. The communication between the server thread and the client handling threads is the queues. That's why I told you to take a look at wait and notify.
I'm thinking that I need a central dispatch thread, one that has a single, thread safe incoming message queue, that each client-incoming thread has a reference to, and a collection of thread safe outgoing message queues that go to each client-outgoing thread.The queue doesn't need to be thread safe, but yes, you can of course use a thread safe if you want to. (wait/notify must be called from synchronized blocks).
>
Are there thread safe queues like this, preferebaly a Generic queue?Yes the are in the concurrency package. (That was added in Java 5)
Kaj

Similar Messages

(Multiple Consumers) vs (Multi-threaded Message Processing after reception)

Hi,
The question pertains to the following scenario:
1. A single input gateway (queue) for messages.
2. Messages arriving from different systems. High incidence during specific periods
3. Message should be processed in near real-time as and when it arrives.
4. A non-polling (async) client.
I'd thought of two diff approaches for it:
1> Have a lightweight single-threaded message consumer -
init connection etc and register a listener (both msg and excep).
start connection . wait indefinitely
Listener onMessage creates new thread for working and returns.
Worker thread - parses xml in message and

Here is the new code:
     public static void writeXML(DataOutputStream out, String xml) {
          byte[] byteArray = xml.getBytes();
          try {
               int length = byteArray.length;
               out.writeInt(length);
               out.write(byteArray);
               out.flush();
          } catch (IOException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
     public static String receiveXML(DataInputStream in){
          int id = (new Date()).hashCode();
          try {
               int lengthToRead = in.readInt();
               byte[] byteRead = new byte[lengthToRead];
               in.readFully(byteRead);
               String s = new String(byteRead);
               return (s);
          } catch (IOException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
          return null;
     }P.S. By changing the code I meant that I was sending the full byte array instead of sending parts as sabre suggested.

How to write a multi threaded Cache Event Listener

I have a distributed data cache called tokenCache for my application. I have also added a mapListener to this cache to listen to a particular kind of events.
tokenCache.addMapListener((MapListener) new TokenCacheListenerBean(), new MapEventFilter(tokenFilter), false);
So bascially everytime a token (The domain object of this cache) is updated the entryUpdated() method in my EJB TokenCacheListenerBean is invoked.
The issue I have though is that, from what I observe on running my code is that the Cache Listener is single threaded. So if two Token Objects on my tokenCache are updated,
lets say Token Object A and Token Object B one after the other, the entryUpdated() method in my EJB is invoked for Token Object A and once the invocation is complete
then the entryUpdated() method is invoked again for Token Object B(). At a given point of time there is only one instance of TokenCacheListenerBean EJB. Is there a way to
make this happen in multi-threaded manner ?
Is there a configuration setting somewhere which allows multiple CacheListeners to be instantiated at a given point of time ?
TokenCacheListenerBean EJB_
package oracle.communications.activation.asap.ace;
import java.util.Iterator;
import java.util.Set;
import java.util.logging.Logger;
import javax.ejb.Stateless;
import com.tangosol.net.NamedCache;
import com.tangosol.util.MapEvent;
import com.tangosol.util.MapListener;
import com.tangosol.util.ValueUpdater;
import com.tangosol.util.extractor.PofExtractor;
import com.tangosol.util.extractor.PofUpdater;
import com.tangosol.util.filter.EqualsFilter;
import com.tangosol.util.filter.LikeFilter;
import com.tangosol.util.filter.LimitFilter;
import com.tangosol.util.processor.UpdaterProcessor;
* Session Bean implementation class TokenCacheListenerBean
@Stateless
public class TokenCacheListenerBean implements TokenCacheListenerBeanRemote, TokenCacheListenerBeanLocal, MapListener {
NamedCache asdlCache;
NamedCache tokenCache;
private final int PAGE_SIZE = 1;
private static Logger logger = Logger.getLogger(ConnectionManager.class.getName());;
* An instance of the JCAModeler EJB, represents the JCA-JNEP
JCAModeler jcaBean;
* Default constructor.
public TokenCacheListenerBean() {
// TODO Auto-generated constructor stub
public void entryDeleted(MapEvent Event) {
public void entryInserted(MapEvent Event) {
public void entryUpdated(MapEvent Event) {
Token newToken = (Token) Event.getNewValue();
Token oldToken = (Token) Event.getOldValue();
if ((oldToken.getState() == Token.TOKEN_RESERVED)
&& (newToken.getState()== Token.TOKEN_AVAILABLE)) {
String networkID = newToken.getNeID();
asdlCache = AceCacheFactory.getCache("asdlCache");
tokenCache = AceCacheFactory.getCache("tokenCache");
EqualsFilter filterNE = new EqualsFilter(new PofExtractor(String.class,Asdl.NETWORKID), networkID);
LimitFilter limitFilter = new LimitFilter(filterNE, PAGE_SIZE);
Set removeASDL = asdlCache.keySet(limitFilter);
Iterator asdlIterator = removeASDL.iterator();
if (asdlIterator.hasNext()) {
logger.info(printASDLCache());
ValueUpdater updater = new PofUpdater(Token.STATE);
System.out.println("Token ID:" + newToken.getTokenID());
UpdaterProcessor updaterProcessor = new UpdaterProcessor(updater, Integer.toString(Token.TOKEN_RESERVED));
tokenCache.invoke(newToken.getTokenID(), updaterProcessor);
jcaBean = new JCAModeler(tokenCache);
Object asdlID = asdlIterator.next();
Asdl provisionAsdl = (Asdl) asdlCache.get(asdlID);
asdlCache.remove(asdlID);
jcaBean.provision(provisionAsdl, newToken.getTokenID());
logger.info(ConnectionManager.printTokenCache());
logger.info(printASDLCache());
}

Here is what I am asking!
I have added 2 listeners (Listener A and Listener B) which each listen on for changes made to 2 different token Cache Objects (Token A and Token B).
for (i = 0; i < 2 ; i++) {
Token tokenAdded = new Token(UUID.randomUUID().toString(),TOKEN_AVAILABLE, networkID);
tokenCache.put(tokenAdded.getTokenID(), tokenAdded);
     tokenCache.addMapListener((MapListener) new TokenCacheListener(), tokenAdded.getTokenID(), false);
Now assume that updates are made to Token A and Token B simuntaneosly.
Why do i observe in my diagnostic messages that only one Listener is invoked at a given point of time.
Which means I see Listener A getting invoked and then once invocation of Listener A is complete I see Listener B bieng invoked.
Ideally I would want both listeners to be invoked simultaneously rather than in a one off fashion.
Here is the code for my token cache Listener
package oracle.communications.activation.asap.ace;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.tangosol.net.CacheFactory;
import com.tangosol.net.NamedCache;
import com.tangosol.util.AbstractMapListener;
import com.tangosol.util.Filter;
import com.tangosol.util.MapEvent;
import com.tangosol.util.MapListener;
import com.tangosol.util.ObservableMap;
import com.tangosol.util.ValueUpdater;
import com.tangosol.util.extractor.PofExtractor;
import com.tangosol.util.extractor.PofUpdater;
import com.tangosol.util.filter.AndFilter;
import com.tangosol.util.filter.EqualsFilter;
import com.tangosol.util.filter.LikeFilter;
import com.tangosol.util.filter.LimitFilter;
import com.tangosol.util.processor.UpdaterProcessor;
public class TokenCacheListener extends AbstractMapListener {
     NamedCache asdlCache;
     NamedCache tokenCache;
     AceCacheFactory cacheFactoryBean = new AceCacheFactory();
     private final int PAGE_SIZE = 1;
     private static Logger logger = Logger.getLogger(ConnectionManager.class
               .getName());;
     * An instance of the JCAModeler EJB, represents the JCA-JNEP
     JCAModeler jcaBean;
     * This is a utility method and prints the tokens cache.
     public String printTokenCache() {
          NamedCache tokenCache = cacheFactoryBean.getCache("tokenCache");
          LikeFilter tokenList = new LikeFilter(new PofExtractor(String.class,
                    Token.STATE), "%", (char) 0, false);
          Set keySet = tokenCache.keySet(tokenList);
          StringBuffer cachedTokenList = new StringBuffer("\n################################## Token(s) Cache ##################################");
          int counter = 1;
          for (Object tokenInCache: keySet) {
               Token tokenObject = (Token) tokenCache.get(tokenInCache.toString());
               cachedTokenList.append("\nS.NO:" + (counter++)
                         + "\t ID:" + tokenInCache.toString()
                         + "\t State:" + Token.tokenToString(tokenObject.getState()));
          cachedTokenList.append("\n####################################################################################");
          return cachedTokenList.toString();
     * This method is a utility method and it prints all the ASDL(s) currently present on the
     * asdlCache.
     private String printASDLCache() {
          NamedCache asdlCache = cacheFactoryBean.getCache("asdlCache");
          LikeFilter asdlList = new LikeFilter(new PofExtractor(String.class,
                              Asdl.NETWORKID), "%", (char) 0, false);
          Set keySet = asdlCache.keySet(asdlList);
          StringBuffer cachedASDLList = new StringBuffer("\n################ ASDL Cache ######## ########");
          int counter = 1;
          for (Object asdlInCache: keySet) {
               cachedASDLList.append("\nS.NO:" + (counter++) + "\t ID:" + asdlInCache.toString());
          cachedASDLList.append("\n################ ASDL Cache ######## ########\n");
          return cachedASDLList.toString();
     public TokenCacheListener() {
     public void checkASDLCache(MapEvent Event) {
     // Not currently used
     public void entryUpdated(MapEvent Event) {
          Token newToken = (Token) Event.getNewValue();
          Token oldToken = (Token) Event.getOldValue();
          logger.info("\n=============================================================================================="
                    + "\nTOKEN CACHE LISTENER"
                    + "\n=============================================================================================="
                    + printTokenCache()
                    + "\n==============================================================================================");
          if ((oldToken.getState() == Token.TOKEN_RESERVED)
                    && (newToken.getState()== Token.TOKEN_AVAILABLE)) {
          String networkID = newToken.getNeID();
          asdlCache = cacheFactoryBean.getCache("asdlCache");
          tokenCache = cacheFactoryBean.getCache("tokenCache");
          EqualsFilter filterNE = new EqualsFilter(new PofExtractor(String.class,Asdl.NETWORKID), networkID);
          LimitFilter limitFilter = new LimitFilter(filterNE, PAGE_SIZE);
          Set removeASDL = asdlCache.keySet(limitFilter);
          Iterator asdlIterator = removeASDL.iterator();
          if (asdlIterator.hasNext()) {
          logger.info(printASDLCache());
          ValueUpdater updater = new PofUpdater(Token.STATE);
          System.out.println("Token ID:" + newToken.getTokenID());
          UpdaterProcessor updaterProcessor = new UpdaterProcessor(updater, Integer.toString(Token.TOKEN_RESERVED));
          tokenCache.invoke(newToken.getTokenID(), updaterProcessor);
          jcaBean = new JCAModeler(tokenCache);
          Object asdlID = asdlIterator.next();
          Asdl provisionAsdl = (Asdl) asdlCache.get(asdlID);
          asdlCache.remove(asdlID);
          jcaBean.provision(provisionAsdl, newToken.getTokenID());
          logger.info(printTokenCache());
          logger.info(printASDLCache());
I only see one instance of this listener alive at any given point of time.
Edited by: 807103 on Nov 3, 2011 1:00 PM
Edited by: 807103 on Nov 3, 2011 1:12 PM

Multi-Threaded FTP

Multi-Threaded FTP was a huge attraction for me, and one of the features that sold me on upgrading to Dreamweaver CS6. However, I haven't seen any sign of it in the product or any documentation to help me use it. My files keep transferring in the traditional one-at-a-time way.
Is there something I need to do to enable this feature? Has anybody used this feature yet?

Might not help but I saw this in the comments on David Powers' blog
http://foundationphp.com/blog/2012/04/23/my-verdict-on-dreamweaver-cs6/
"Multi-thread FTP is the default in Dreamweaver CS6. You can neither turn it on nor off. It handles a maximum of three transfers simultaneously in either direction (so you can download at the same time as uploading). However, it doesn’t work with Check In/Check Out."
He also has the following comments in the body of the blog entry:
Multichannel FTP
Let’s be honest. In the past, Dreamweaver’s FTP client was a dog. Not any more. It now supports multichannel transfers, and can even download at the same time as uploading. Orange arrows indicate items queued for transfer. When the transfer begins, the arrow turns green. And if you’re transferring a large item, hovering over the filename displays a tooltip of how much of the file has been transferred. With Dreamweaver CS5.5, it took more than 90 minutes to upload a WordPress site on my internet connection. Now, it’s more than ten times faster.
The FTP error messages are also more meaningful. No one is likely to buy Dreamweaver CS6 for its FTP client alone, but this is a major improvement to the program.

Multi-thread failure - Error in assignment

Hello
I have a c++ program processor running under Windows XP with Oracle 9i. My program access to oracle by an ODBC driver version 9.2.0.4.0. It could be launched in multi-thread to increase performance. When I launch it with one thread everything is fine. When I use several threads I have problems. ODBC driver returns to me a "error in assignment ... General error" message and my updates queries failed. Under SQl server it works without problems. It seems to be a kind of deadlock. When I disable check box in my odbc driver of "enable query timeout" my program encounter a problem and freezes...
Could someone help me ?

user13335017 wrote:
I have thought of the above solutions as workable, however, it is not. Some exhibited errors are:
A. "Attempt to use database while environment is closed." This error applies to 2, 3 and 4 all the way;
B. "Attempt to read / write database while database is closed." This error applies to 3 in particular;
C. "Attempt to close environment while some database is still open." This error applies to 5.
Please help me with designing a better strategy to solve the concurrent issue. Many thanks in advance.All these are expected errors. You should design the application so that you do not close an environment handle while database handles are still open, keep database handles open for as long as operations need to be performed on the underlying databases, open the database handles after opening the database handles, and close database handles before closing the environment handle.
In short, in pseudo-code, you should have something like this:
- open environment handle,
- open database handles,
- perform whatever operations are needed on the databases,
- close database handles,
- close environment handle.
You can refer to the Getting Started with Data Storage and the Getting Started with Transaction Processing guides appropriate for the API you are using, from the Berkeley DB documentation page.
Regards,
Andrei

Multi threading under single file channel

Hi,
We have File-Proxy scenario .
We are using fCC sender channel and using
recordset sequence as varaibale
recordsets per message was 250.
When large size file like 2GB was processed, PI is taking 45-50 min to process the file and from proxy end its taking 8 hrs to process this file.
we are using one channel and 250 recordsets per message by chunking file and process to target. We are following EOIO for sequence for these chunk files.
with this approach in PI target system proxy is taking huge time to process.
experts suggested using multi threading and multiple channels are the ideal solution for this issue.
am expecting with multiple channels and multi threading will cause issue for receiver proxy because of more objects and current approach is fine.
Please suggest any other alternatives we can acheive in PI with respect to this issue?
Note: I checked blog for file chunk option under Adv parameters and I cant use that here as FCC and Mapping is there .
Rgds,
aman

Hi Aman,
We had file to proxy interface and the XML payload of the proxy was around 400mb...to reduce the time taken in PI in mapping step we reduced the XML payload of the proxy by cutting the XML tagnames.
for example an xml field <firstname>Anand</firstname> was converted to <f>Anand</f>
with this we were able to achieve about 40-50% reduction in XML payload the file and a good improvement in the time taken by PI mapping to process the file.
Hope it helps,
Thanks,
Anand

InfoPath: the multi-threading challenge

Or to be more specific: calling a DataSource from a different thread.
A project I'm working on includes an InfoPath form in which some heavy duty tasks are executed. These tasks can take over 10+ seconds to execute. To avoid the GUI to get stuck during execution, multi-threading is implemented. The problem lies in providing
feedback to the user. Several methods have been used, but all end in the exceptions shown below.
Unlike WinForms and such, InfoPath does not seem to provide a way to invoke the GUI. What we are trying to do is change field values to reflect the status of the process. This is done through the MainDataSource. I've tried several methods to call
this datasource through another thread, like invoking a provided delegate, or execution context. However all these methods have similar results.
When calling a method or property on the datasource the following exception is thrown:
System.InvalidOperationException was unhandled
Message="Operation is not valid due to the current state of the object."
Source="Microsoft.Office.InfoPath.Client.Internal.Host"
StackTrace:
       at Microsoft.Office.Interop.InfoPath.SemiTrust.ICLRExtensionsWrapper.IncrementSqmPoint(Int32 idDataPt)
       at Microsoft.Office.InfoPath.Internal.DataSourceHost.CreateNavigator()
       at Form1.FormCode.ContextCallbackMethod(Object obj) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 74
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at Form1.FormCode.ThreadMethod(Object myParamsObj) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 68
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart(Object obj)
This seems to indicate the DataSource is locked for some reason. Even the ReadOnly property can not be read.
When calling the SetValue method on an XPathNavigator provided by a datasource and passed through another thread, the following exception is thrown:
System.AccessViolationException was unhandled
Message="Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
Source="Microsoft.Office.InfoPath.Client.Internal.Host.Interop"
StackTrace:
       at Microsoft.MsoOffice.InfoPath.MsxmlInterop.NativeHelpers.SetText(IXMLDOMNode* , Char* )
       at Microsoft.MsoOffice.InfoPath.MsxmlInterop.MsxmlNodeImpl.set_Text(String strText)
       at Microsoft.Office.InfoPath.MsxmlNavigator.SetValue(String value)
       at Form1.FormCode.DelegateMethod(XPathNavigator nav) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 81
       at Form1.FormCode.ThreadMethod(Object myParamsObj) in E:\Projects\InfoPath Multithreading\Source\Form1\FormCode.cs:line 70
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart(Object obj)
I have searched through the internet but am unable to find any useful information about this subject. There are only a few weeks remaining before the deadline. A work-around has been implemented, but since it requires additional active user interaction
it is far from ideal. I hope you can help me in finding a solution.

For anyone who is still interested all this time later....
I wouldn't use a Dispatcher in InfoPath simply because InfoPath requires .Net 2.0 only and Dispatcher was not added until .Net 3.0 which means you would have to enforce installation of .Net 3.0 yourself.
There is an easy alternative which is SynchronizationContext (more specifically a WindowsFormsSynchronizationContext).
Also I suggest you do not use ThreadStart but rather use one of the more modern and well known threading paradigms. A good alternative is a BackgroundWorker.
e.g.
private BackgroundWorker _Worker;
public void InternalStartup()
InitializeWorker();
((ButtonEvent)EventManager.ControlEvents["Button"]).Clicked += new ClickedEventHandler(ButtonClick);
public void InitializeWorker()
_Worker = new BackgroundWorker();
_Worker.WorkerReportsProgress = true;
_Rorker.WorkerSupportsCancellation = true;
_Worker.DoWork += new DoWorkEventHandler(_Worker_DoWork);
_Worker.ProgressChanged += new ProgressChangedEventHandler(_Worker_ProgressChanged);
_Worker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(_Worker_RunWorkerCompleted);
public void ButtonClick(object sender, ClickedEventArgs e)
if (_Worker.IsBusy)
_Worker.CancelAsync();
else
// Very important to include this line!
AsyncOperationManager.SynchronizationContext = new WindowsFormsSynchronizationContext();
_Worker.RunWorkerAsync();
void _Worker_DoWork(object sender, DoWorkEventArgs e)
// Do stuff in another thread and report back to the UI thread.
object state;
int percentage = 0;
_Worker.ReportProgress(percentage, state).
public void _Worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
// This is called on the thread that started the worker.
// In this case the UI thread which means it is safe to use the MainDataSource.
CreateNavigator().SelectSingleNode("my:Main/my:Progress", NamespaceManager).SetValue(e.ProgressPercentage);
void _Worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
// Do anything you want to do on completion here.
One thing of note is that the SynchronizationContext in InfoPath for some reason or other always seems to be Null. The result is that when you call RunWorkerAsync() it captures the current synchronization context (null) which means the default is used and
a ProgressChanged is called on a new thread each time. To prevent this we need to manually set the context before calling RunWorkerAsync() which is done using the AsyncOperationManager.

Oracle 8 on Linux in Multi-Thread mode

I installed Oracle 8.0.5.0.0 on Linux RedHat 5.1
But I cann't startup database in multi-threaed mode.
When I try to startup DB the errors follow
SVRMGR> startup;
ORA-00101: invalid specification for system parameter
MTS_DISPATCHERS
ORA-00102: network protocol
(ADDRESS=(PARTIAL=YES)(PROTOCOL=tcp)) cannot be used by
dispatchers
My configuration files are:
listener.ora
LISTENER =
(ADDRESS_LIST =
(ADDRESS= (PROTOCOL= IPC)(KEY= orcl))
(ADDRESS= (PROTOCOL= IPC)(KEY= PNPKEY))
(ADDRESS= (PROTOCOL= TCP)(Host=
pcstar.kharkov.ua)(Port= 1521))
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(GLOBAL_DBNAME= pcstar.kharkov.ua)
(ORACLE_HOME= /usr/oracle)
(SID_NAME = orcl)
(SID_DESC =
(SID_NAME = extproc)
(ORACLE_HOME = /usr/oracle)
(PROGRAM = extproc)
STARTUP_WAIT_TIME_LISTENER = 0
CONNECT_TIMEOUT_LISTENER = 10
TRACE_LEVEL_LISTENER = OFF
tnslistener working normally
tnsnames.ora
extproc_connection_data =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = IPC)(KEY = orcl))
(CONNECT_DATA = (SID = extproc))
orcl =
(DESCRIPTION =
(ADDRESS = (PROTOCOL= TCP)(Host=
pcstar.pcstar.kharkov.ua)(Port= 1521))
(CONNECT_DATA = (SID = orcl))
orcl_BEQ =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = BEQ)(PROGRAM = /usr/oracle)
(argv0 = oracleorcl)
(args = '(DESCRIPTION =
(LOCAL=YES)(ADDRESS=(PROTOCOL=BEQ)))')
(envs =
'ORACLE_HOME=/usr/oracle,ORACLE_SID=orcl')
initorcl.ora
mts_dispatchers="tcp,1"
mts_max_dispatchers=3
mts_servers=1
mts_max_servers=5
mts_service=orcl
mts_listener_address="(ADDRESS=(PROTOCOL=tcp)(Host=pcstar)(Por
t=1521))"
If anybody started server in Multi-Thread mode, mail me
[email protected]
Best Regards!
Gennady Saldiga
null

Yes, the MTS for TCP protocol does not work. A patch will be
released soon for the production release with the fix for
the MTS problem.
Maturi
Satoshi Hirai (guest) wrote:
: Gennady Saldiga (guest) wrote:
: : I installed Oracle 8.0.5.0.0 on Linux RedHat 5.1
: : But I cann't startup database in multi-threaed mode.
: : When I try to startup DB the errors follow
: : SVRMGR> startup;
: : ORA-00101: invalid specification for system parameter
: : MTS_DISPATCHERS
: : ORA-00102: network protocol
: : (ADDRESS=(PARTIAL=YES)(PROTOCOL=tcp)) cannot be used by
: : dispatchers
: : My configuration files are:
: : listener.ora
: : LISTENER =
: : (ADDRESS_LIST =
: : (ADDRESS= (PROTOCOL= IPC)(KEY= orcl))
: : (ADDRESS= (PROTOCOL= IPC)(KEY= PNPKEY))
: : (ADDRESS= (PROTOCOL= TCP)(Host=
: : pcstar.kharkov.ua)(Port= 1521))
: : SID_LIST_LISTENER =
: : (SID_LIST =
: : (SID_DESC =
: : (GLOBAL_DBNAME= pcstar.kharkov.ua)
: : (ORACLE_HOME= /usr/oracle)
: : (SID_NAME = orcl)
: : (SID_DESC =
: : (SID_NAME = extproc)
: : (ORACLE_HOME = /usr/oracle)
: : (PROGRAM = extproc)
: : STARTUP_WAIT_TIME_LISTENER = 0
: : CONNECT_TIMEOUT_LISTENER = 10
: : TRACE_LEVEL_LISTENER = OFF
: : tnslistener working normally
: : tnsnames.ora
: : extproc_connection_data =
: : (DESCRIPTION =
: : (ADDRESS = (PROTOCOL = IPC)(KEY = orcl))
: : (CONNECT_DATA = (SID = extproc))
: : orcl =
: : (DESCRIPTION =
: : (ADDRESS = (PROTOCOL= TCP)(Host=
: : pcstar.pcstar.kharkov.ua)(Port= 1521))
: : (CONNECT_DATA = (SID = orcl))
: : orcl_BEQ =
: : (DESCRIPTION =
: : (ADDRESS = (PROTOCOL = BEQ)(PROGRAM = /usr/oracle)
: : (argv0 = oracleorcl)
: : (args = '(DESCRIPTION =
: : (LOCAL=YES)(ADDRESS=(PROTOCOL=BEQ)))')
: : (envs =
: : 'ORACLE_HOME=/usr/oracle,ORACLE_SID=orcl')
: : initorcl.ora
: : mts_dispatchers="tcp,1"
: : mts_max_dispatchers=3
: : mts_servers=1
: : mts_max_servers=5
: : mts_service=orcl
mts_listener_address="(ADDRESS=(PROTOCOL=tcp)(Host=pcstar)(Por
: : t=1521))"
: : If anybody started server in Multi-Thread mode, mail me
: : [email protected]
: : Best Regards!
: : Gennady Saldiga
: Hi!
: Same problem occured on my environment (Debian GNU/Linux 2.0).
: But I succeeded to start Multi-thread server on ipc protocol.
: My current configuration file (mts_* in init.ora) as follows:
: mts_dispatchers="ipc,1"
: mts_max_dispatchers=10
: mts_servers=1
: mts_max_servers=10
: mts_service=orcl
: # I confirmed mts_listener_address syntax by manual and
: # v$parameter.
: # Net8 Admn man says: If you have multiple MTS_LISTENER_ADDRESS
: # parameters, they must be adjacent to each other in your
: # initialization file.
mts_listener_address="(ADDRESS=(PROTOCOL=TCP)(host=j-00872)(port=
: 1521))"
: mts_listener_address="(ADDRESS=(PROTOCOL=IPC)(KEY=orcl))"
: So I tested MTS_DISPATCHERS parameter's other syntax.
: The test results are:
: # mts_dispatchers="ipc,1"
: # OK
: # mts_dispatchers="tcp,1"
: # ORA-00101,ORA-00102 occured
: # mts_dispatchers="TCP,1"
: # ORA-00101,ORA-00102 occured
: # mts_dispatchers="ipc,1","tcp,1"
: # ORA-00101,ORA-00102 occured
: # mts_dispatchers="(ADDRESS=(PARTIAL=YES)(PROTOCOL=tcp))"
: # ORA-00101,ORA-00102 occured
: # mts_dispatchers="(ADDRESS=(PARTIAL=NO)(PROTOCOL=tcp))"
: # ORA-00101,ORA-00102 occured
: # mts_dispatchers="(ADDRESS=(PARTIAL=YES)(PROTOCOL=ipc))"
: # OK
: # mts_dispatchers="(PROTOCOL=IPC) (DISPATCHERS=3)"
: # OK
: # mts_dispatchers="(PROTOCOL=TCP) (DISPATCHERS=3)"
: # ORA-00101,ORA-00102 occured
: # mts_dispatchers="(ADDRESS=(PROTOCOL=IPC)(KEY=orcl))
: (dispatchers=3)"
: # OK
mts_dispatchers="(ADDRESS=(PROTOCOL=TCP)(host=j-00872)(port=1521)
: ) (dispatcher
: s=3)"
: # ORA-00101,ORA-00102 occured
mts_dispatchers="(description=(ADDRESS=(PROTOCOL=IPC)(KEY=orcl))(
: connect_data=
: (sid=orcl))) (dispatchers=3)"
: # OK
mts_dispatchers="(description=(ADDRESS=(PROTOCOL=TCP)(host=j-0087
: 2)(port=1521)
: )(connect_data=(sid=orcl))) (dispatchers=3)"
: # ORA-00101,ORA-00102 occured
: ### While the test, sometimes ORA-00472 (ORA-00472: PMON
process
: ### terminated with error) occured when instance shutdown.
: ### I think the error reported in another message
: ### on the same thread.
: It seems dispatcher is not binded to tcp protocol adapter.
: Does anybody have more information about Multi-thread server
: using TCP protocol.
: ### Please forgive my bad english.
: Thank you.
: Satoshi Hirai
null

Crystal Report XI u2013 Multi Thread - function PEOpenEngineEx failed. Reason:

In Crystal Report XI u2013 Multi Thread - function PEOpenEngineEx failed. Reason: Report engine not opened
Hi
I am using Crystal report XI with Delphi 7
OS: Windows XP.
Delphi 7
CR Version: Crystal Report XI
In Crystal Report XI While calling PEOpenEngineEx() by setting Engine option as multi thread, It failed with error message u201CError:512 Report Engine Not Openedu201D
Code Change in Delphi 7 UCrpe32.pas (Crystal Reports XI Release 1 - Service Pack 3 and Service Pack 4)
aEngineOptions.openEngineType := PE_OE_MULTI_THREADED;
FEngineOpened := FCrpeEngine.PEOpenEngineEx(EngineOptions);
I tried the same with Crystal Report 8.5 (above mentioned code change) Function PEOpenEngineEx() working fine.
How to overcome this error to make work Multi Thread using CR XI?

I found that it is bug Release 2 and the script server_patch_xir2 resolved it.

Multi threaded programming

I am quite new to multi threaded programming.
The problem I am facing in my code is as follows:
I can instantiate 1-10 threads from my controller class. For example if my controller class generates 10 threads, 5 threads
finish the task they are assigned to do(i.e send SMS and Update the Database) and the other 5 threads eventhough send SMS but
get stuck when they are supposed to update the Database (this is inferred from the logs).
Due to this problem my controller class remains in a wait state as I am using the join() method and some of the threads never
join.
Another interesting observation is that it always happens that the thread numbered 0-5 always get stuck at the exact point
where database has to be updated and thread number 6-10 complete their task. Same is the case when i instantiate 2 threads, i
thread completes its task and another thread gets stuck, again at the same point.
I am using Connection Pooling to connect to the database.
I am sure that the problem is with the query
int j=dbObject.execute_pst("UPDATE table SET flag='true' WHERE message IN("+trueFlag+")",con);
where true flag is a comma seperated string containing some ID's.
What i cannot understand is why some of the threads (almost 50% of them), work fine with this query and the others get stuck
(i.e. just wait at this query during runtime)

The problem must lie in the connection, as the SQL statement is to basic to cause an endless loop inside the DBMS. If you are in doubt, try the setMaxRows() method of the Statement interface, I'm using Sybase and it also limits the number of rows processed in update and delete statements (which I'm pretty sure is buggy, but you can still try it).
Which DBMS are you using by the way?

Multi-threaded performance server using 2 ports to two-way communication

Hi, I'm new in the forums so welcome everyone. I'm developing now an online computer game based on orginal Polish board-game, but it doesn't mean. Important is that I need to develope a high-performance multi-threaded server, which can serve... let's say few hundres of games, and a thousend of players simulateously. My server works on two ports/sockets.
First one is represented by "ServerSocketChannel clientConSsc" in my code. The main thread in my server class which invokes the method "run()" (which You can see below), registers clientConSsc with Selector and then repeatingly accepts incoming connections from clients on this socket. When connection(channel) is estabilished and clients wants to write some request to this channel, the main thread on server creates a new instance of class "RequestHandler" which extends Thread and handles this request (reads the request from channel, makes some changes on server, spreads some new messages to other clients in the same game and so on... everything on the same socket/port/channel). Then the channel/connection is closed by the server - I call such connections: "a short connections". In the same time the main thread continues the loop and is still able to accept connections from another players. That's the idea of multi-threaded server, right? :) And to this point, everything works fine, but... what if the server wants to trigger some new command, write new information to client?
Server could have tried to open a SocketChannel to client's IP address, but then the client programme would have to create and ServerSocketChannel object, bind it to some InetAddress and then... and then client becomes a server! - that breaks the idea of client-server cooperation and demands on players of my game to have routed some port on their machines. To resolve this problem I made some sort of "system" which, when some player/client is logging into my server, accepts second (this time constant, not "short") connection on the second port I mentoined on the beginning. This connection is held in variable "SocketChannel serverCon" of class "Player" - which reflects a player logged onto server. Server maintains every such connection till the client logs off. After the connection is accepted, the player whom connection it was is added to collection called "playersToRegisterToWrite". After the Selector.selectNow() is invoked (as You can see in the code below), each and every player's connection is registered in selector (with selection key - OP_WRITE and attachment pointing on owning player). In the same time client's code is trying to read some bytes from this connection and blocks on it until some bytes are written to this connection. When server wants to "tell" something to client, deliver some message/command, it creates a new instance of class which extends an abstract class called "ServerAction" (another new thread) and adds it to collection "actionsToDo". In ServerAction's method "run()" there are whole code to interact with client (e.g. send an update of players' list, an update of games' list, a chat message). Finnaly when Selector informs the server that some connection is writable (some client is waiting for commands), then server checks if there's any "actionToDo" involving this client/player. If there is, it unregisters the connection from Selector (so no other ServerAction (thread) can write on this connection) and starts the action. At the end of every "run()" method of subclass of ServerAction there's a code, which again adds the player to collection "playersToRegisterToWrite", so the player's connection can again be registered in Selector and the player can again receive informations from server - after it consumed THIS "ServerAction".
It looks to me like it should be working fine, but it's not. When I test my server and clients on the same machine (no ping/latency) everything seems to be working fine. But when it comes to play my game with somebody even on LAN or through the Internet there comes the problems. My first socket I describe (and first type of connections - short connections) works perfectly fine, so the requests triggered by client are delivered and handled properly. But the second socket is cirppling. For example: the server triggers a command refering to an update of clients logged to server' list. It is triggered by Selector so the client should be ready to read data from server, so the server sends data! And the client never receives it... Why?
It experimented a whole lot of time on SocketChannel's method "configureBlocking(boolean)", but it never helps. I think the client should always block it's listening thread on connection, contratry to server which is ment to be fast, so it should send the data through non-blocking channels. Am I right? Are there any rules refering blocking configuration of SocketChannels?
I will be grateful for every answer. To help You out I attach also drafts from run()'s methods of my classes.
Server's main method - main thread :
    public void run() {
       try {
            selector = Selector.open();
            clientConSsc.configureBlocking(false);
            clientConSsc.register(selector , SelectionKey.OP_ACCEPT);
            while(serverRunning) {
                try {
                    selector.selectNow();
                    Iterator it;
                    synchronized(playersToRegisterToWrite) {
                        it = playersToRegisterToWrite.iterator();
                        while(it.hasNext()) {
                            Player player = (Player)it.next();
                            it.remove();
                            player.serverCon.configureBlocking(false);
                            player.serverCon.register(selector , SelectionKey.OP_WRITE , player);
                    Set keys = selector.selectedKeys() {
                    it = keys.iterator();
                    while(it.hasNext()) {
                        SelectionKey key = (SelectionKey)it.next();
                        if(key.isAcceptable()) {
                            it.remove();
                            clientCon = clientConSsc.accept();
                            clientCon.configureBlocking(false);
                            clientCon.register(selector , SelectionKey.OP_READ);
                            continue;
                        if(key.isReadable()) {
                            it.remove();
                            key.cancel();
                            new RequestHandler(this , (SocketChannel)key.channel()).start();
                            continue;
                        if(key.isWritable()) {
                            if(key.attachment() != null ) {
                                ServerAction action = null;
                                synchronized(actionsToDo) {
                                    Iterator aIt = actionsToDo.iterator();
                                    while(aIt.hasNext()) {
                                        ServerAction temp = (ServerAction)aIt.next();
                                        if(temp.getPlayer().equals((Player)key.attachment())) {
                                            action = temp;
                                            aIt.remove();
                                            break;
                                if(action != null) {
                                    key.channel().configureBlocking(false);
                                    it.remove();
                                    key.cancel();
                                    action.start();
                            continue;
                } catch(Exception e) {
                    statusArea.append(e.toString() + "\n");
                    e.printStackTrace();
                    continue;
        } catch(ClosedChannelException e) {
            statusArea.append(e.toString() + "\n");
        } catch(IOException e) {
            statusArea.append(e.toString() + "\n");
            A part of server's RequestHandler's class' method run() - the method which handles requests triggered by client on first port:
public void run() {
        boolean served = false;
            try {
                channel.configureBlocking(true);
                retryCount++;
                retry = false;
                String command = ns.readText(channel).trim();
                ns.statusArea.append("ktos przesyla komende: " + command + "\n");
                if(command != null && !command.equals("ERROR")) {
                    String[] cmd = command.split("�");
                    ns.statusArea.append("komenda: " + cmd[0] + "\n");
                    if(cmd[0].equals("CHAT")) {
                        if(cmd.length != 5) {
                            retry();
                        } else {
                            if(cmd[2].equals("NOGAME")) {      // jezeli nie ma okreslonej gry czyli rozsylamy do wszystkich
                                for(int i = 0 ; i < ns.loggedPlayersListItems.size() ; i++) {
                                    Player current = (Player)ns.loggedPlayersListItems.get(i);
                                    if(current.state == Player.CHOOSING && !current.equals(new Player(Integer.parseInt(cmd[1]))))   // jezeli gracz jest w okienku wybierania gry to wysylamy mu broadcast
                                        ns.actionsToDo.add(new SendMsg(ns , current , "CHAT�" + cmd[1] + "�" + cmd[3] + "�" + cmd[4]));
                            } else {
                                Game game = (Game)ns.gamesListItems.get(ns.gamesListItems.indexOf(new Game(Integer.parseInt(cmd[2]))));
                                for(int i = 0 ; i < game.players.size() ; i++) {
                                    Player current = (Player)game.players.get(i);
                                    if(!current.equals(new Player(Integer.parseInt(cmd[1]))))
                                        ns.actionsToDo.add(new SendMsg(ns , current , "CHAT�" + cmd[1] + "�" + cmd[3] + "�" + cmd[4]));
                            served = true;
                    } else if(cmd[0].equals("GETGAMEINFO")) {
                        if(cmd.length != 3)
                            retry();
                        else {
                            int gameID = Integer.parseInt(cmd[2]);
                            ns.statusArea.append("poproszono o informacje o grze nr: " + gameID + "\n");
                            Game checkedGame = new Game(gameID);
                            if(ns.gamesListItems.contains(checkedGame)) {
                                Game game = (Game)ns.gamesListItems.get(ns.gamesListItems.indexOf(checkedGame));
                                channel.configureBlocking(true);
                                ObjectOutputStream oos = new ObjectOutputStream(channel.socket().getOutputStream());
                                oos.writeObject(game);
                                oos.writeObject(game.players);
                                oos.flush();
                                ns.statusArea.append("wyslano informacje o grze nr: " + gameID + "\n");
                            } else {
                                ns.statusArea.append("brak gry o nr: " + gameID + "\n");
                            served = true;
            } catch(IOException e) {
                e.printStackTrace();
        if(!served) {
            ns.findAndDisconnectPlayer(channel);
        try {
            channel.close();
        } catch(IOException e) {
            e.printStackTrace();
    }An example of ServerAction's subclass - the class which triggers server commands to client on second port:
class UpdateLoggedPlayersList extends ServerAction {
    public UpdateLoggedPlayersList(NeuroServer ns , Player player) {
        super(ns , player);
    public void run() {
        try {
            serverCon.configureBlocking(true);
            ns.sendText("UPDATELOGGEDPLAYERSLIST" , serverCon);
            if(ns.readText(serverCon).equals("OK")) {
                ObjectOutputStream oos = new ObjectOutputStream(serverCon.socket().getOutputStream());
                oos.writeObject(ns.loggedPlayersListItems);
                oos.flush();
            synchronized(ns.playersToRegisterToWrite) {
                 ns.playersToRegisterToWrite.add(player);
        } catch(IOException e) {
            e.printStackTrace();
}A part of client's CmdHandler's class' method run() - the method which handles commands triggered by server:
public void run() {
    try {
        while(works) {
            String command = nc.readText(nc.serverCon);
            System.out.println("Server przesyla komende: " + command + "\n");
            String[] cmd = command.split("�");
            if(cmd[0] != null && !cmd[0].equals("ERROR")) {
                if(cmd[0].equals("CHAT")) {
                    if(nc.chooseGameDialog != null && nc.chooseGameDialog.isVisible()) {     // jezeli na wybieraniu gry
                        newChatEntry(cmd[2] , null , cmd[3] , nc.chooseGameDialog.chatPane);
                    } else if(nc.readyDialog != null && nc.readyDialog.isVisible()) { // jesli na przygotowywaniu
                        Player sender = (Player)nc.actGame.players.get(nc.actGame.players.indexOf(new Player(Integer.parseInt(cmd[1]))));
                        newChatEntry(cmd[2] , sender.fraction , cmd[3] , nc.readyDialog.chatPane);
                    } else if(nc.ng != null) {                   // jesli w grze
                        Player sender = (Player)nc.actGame.players.get(nc.actGame.players.indexOf(new Player(Integer.parseInt(cmd[1]))));
                        newChatEntry(cmd[2] , sender.fraction , cmd[3] , nc.ng.inGameChatPane);
                } else if(cmd[0].equals("UPDATELOGGEDPLAYERSLIST")) {
                    nc.sendText("OK" , nc.serverCon , false);
                    nc.serverCon.configureBlocking(true);
                    ObjectInputStream ois = new ObjectInputStream(nc.serverCon.socket().getInputStream());
                    DefaultListModel players = (DefaultListModel)ois.readObject();
                    nc.chooseGameDialog.updateLoggedPlayersList(players);
    } catch(IndexOutOfBoundsException e) {
        System.out.println(e);
    } catch(IOException e) {
        System.out.println(e);
    } catch(ClassNotFoundException e) {
        System.out.println(e);
}And two methods I used in codes above: sendText(String text , SocketChannel sc) and readText(SocketChannel sc) - they are my "utility" methods, which I use to send and receive Strings through specified SocketChannels.
boolean sendText(String text , SocketChannel sc) {
    ByteBuffer bbuf = ByteBuffer.allocate(BSIZE);
    boolean sendRetry;
    boolean sent = false;
    do {
        sendRetry = false;
        try {
            StringBuffer cmd = new StringBuffer();
            cmd.setLength(0);
            if(text.length()+4 < 100)
                cmd.append("0");
            if(text.length()+4 < 10)
                cmd.append("0");
            cmd.append(Integer.toString(text.length()+4) + "�");
            cmd.append(text);
            cmd.append("\n");
            bbuf = charset.encode(CharBuffer.wrap(cmd));
            sc.write(bbuf);
            bbuf.clear();
            int n = sc.read(bbuf);
            if(n == 1) {
                bbuf.flip();
                Byte re = bbuf.get();
                if(re == 1) {
                    sendRetry = true;
                } else {
                    sent = true;
        } catch(Exception e) {
            findAndDisconnectPlayer(sc);
            try {
                sc.close();
            } catch(IOException f) {
                f.printStackTrace();
            return false;
    } while(!sent && sendRetry);
    return true;
String readText(SocketChannel sc) {
    ByteBuffer bbuf = ByteBuffer.allocate(BSIZE);
    int readRetryCount = -1;
    boolean readRetry;
    do {
        readRetry = false;
        readRetryCount++;
        StringBuffer cmd = new StringBuffer();
        cmd.setLength(0);
        bbuf.clear();
        try {
            readLoop:
            while(true) {
                int n = sc.read(bbuf);
                if(n > 0) {
                    bbuf.flip();
                    CharBuffer cbuf = charset.decode(bbuf);
                    while(cbuf.hasRemaining()) {
                        char c = cbuf.get();
                        if(c == '\r' || c == '\n') break readLoop;
                        cmd.append(c);
                } else break;
            statusArea.append(Thread.currentThread().getId() + " readText() odczytuje: " + cmd.toString() + "\n");
            if(cmd.length() < 3 || Integer.parseInt(cmd.substring(0 , 3)) != cmd.length()) {
                sc.write(ByteBuffer.wrap(new byte[] {1}));
                readRetry = true;
            } else {
                sc.write(ByteBuffer.wrap(new byte[] {0}));    // length OK
                return cmd.toString().substring(4 , cmd.toString().length());
        } catch(Exception e) {
            findAndDisconnectPlayer(sc);
            try {
                sc.close();
            } catch(IOException f) {
                f.printStackTrace();
            return "ERROR";
    } while(readRetry && readRetryCount < 3);
    findAndDisconnectPlayer(sc);
    try {
        sc.close();
    } catch(IOException e) {
        e.printStackTrace();
    return "ERROR";
}Edited by: Kakalec on Jul 23, 2008 11:04 AM

You seem to be using a horrendous mixture of PrintWriters, BufferedReaders, ObjectOutputStreams, and no doubt ObjectInputStreams. You can't do that.
Some rules about this:
(a) Whenever you use a stream or reader or writer on a socket, you must allocate it once for the life of the socket, not every time you want to do an I/O.
There are many reasons for this including losing buffered data in the old stream and auto-closure of the socket on garbage-collection of the old stream.
(b) You can't mix stream types on the same socket. (i) If you're writing objects, use an ObjectOutputStream, you must read with an ObjectInputStream, and you can't read or write anything that isn't supported by the API of ObjectOutputStream. (ii) If you're writing lines, use a BufferedWriter and a BufferedReader at the other end. If you're writing characters, use a Writer and a Reader. (iii) If you're writing primitive data or UTF strings, use a DataOutputStream and a DataInputStream. (iv) If you're writing bytes, use DataOutputStream and a DataInputStream or an OutputStream and an InputStream. You can't mix (i), (ii), (iii), and (iv).
(c) Don't use PrintWriter or PrintStream over the network. They swallow exceptions that you need to know about. They are for writing to the console, or log files, where you don't really care about exceptions.
(d) Call flush() before reading.
(e) Always close the 'outermost' output stream or writer of a socket, never the input stream or the socket itself. Closing any of these closes the socket and therefore makes the other stream unusable, but only closing the output stream/writer will flush it.

Multi-thread application recompile object with make but runs with old value

Hi. I am working on a simulation in Java, and there is some behavior going on that I cannot understand. Granted, I'm a mechanical engineer, not a CS student (a fact that is probably made obvious by the code I'm posting below). The simulation comprises three parts: a controller, a robot, and a 3-d sensor. Here's the code for the "Simulation" application.
class Simulation {
    void go() {
     ThreeDSensor sensorRunner = new ThreeDSensor();
     VSController controllerRunner = new VSController();
     KukaKR15SL robotRunner = new KukaKR15SL();
     Thread sensorThread = new Thread(sensorRunner);
     Thread controllerThread = new Thread(controllerRunner);
     Thread robotThread = new Thread(robotRunner);
     sensorThread.start();
     try {
         Thread.sleep(1000); // Give sensorThread time to start in order to catch first triggers
     } catch(InterruptedException ex) {
         ex.printStackTrace();
     controllerThread.start();
     try {
         Thread.sleep(1000); // Give controllerThread time to open the socket for communication with robotThread
     } catch(InterruptedException ex) {
         ex.printStackTrace();
     robotThread.start();
    public static void main(String[] args) {
     Simulation sim = new Simulation();
     sim.go();
}I guess the big reason I'm using multi-threading is that once this simulation is working I want to be able to just run VSController alone and have it interface with a robot controller and a PC performing image processing. So with multiple threads I'm sending TCP and UDP messages around just like the final system will.
I have made an object for my VSController that just stores values used by the simulation. That way I could have them all in one place instead of hunting through methods to change them. One example is "double noiseThreshold". Quickly, here is the code for "ControllerSettings.java".
class ControllerSettings {
    final double cameraXOffset = 0; // If > 0 then the origin of the camera CS is not on the center line of the lens
    final double cameraYOffset = 0; // If > 0 then the origin of the camera CS is not on the center line of the lens
    final double cameraZOffset = 700; // The distance that must be kept between the camera and the target
    // Error magnitude less than this is disregarded (in centimeters if roundingData else in millimeters)
    final double noiseThreshold = 60;
    final boolean estimatingEndPoints = false; // If the controller is using two images per cycle then true
    final boolean roundingData = false;
    final boolean using3DData = true; // How double[] sent from Matlab image processing is used
     * If the robot controller uses the output of this controller to command
     * motions in cartesian space then true. This is used in two places: 1) initial guess of Jacobian,
     * and 2) "commandType" element sent to robot controller.
    final boolean useRobotControllerModel = false;
    final double thetaBumpValueForEstimationOfJacobian = .1; // Distance each joint is jogged in estimation process
    final double bumpDistance = 50; // Distance robot moves each time (magnitude of translation in mm)
    final double limitAngular = .5; // Max amout robot joint will be commanded to rotate (in degrees)
}And here is some pertinent code from "VSController.java".
class VSController implements Runnable{
    ControllerSettings cSettings; // Stores all the preferences used by the controller
    NGN controller; // This is the controller algorithm.
    int dof; // The degrees of freedom of the robot being controlled
    KukaSendData ksd; // This provides communication to the robot.
    protected DatagramSocket socketForVisionSystem = null;
    ImageFeaturesData ifd; // This parses and stores data from the image system.
    double[] errorVector; // This is what's acted on by the algorithm
    PrintWriter errorTrackerOut = null; // For analysis of error vector
    public void run() {
     VSController vsc = new VSController();
     vsc.go();
    public void go() {
     initWriters();
     cSettings = new ControllerSettings();
    public boolean isNoise() {
     boolean ret = false;
     double magnitude = 0;
     for (int i = 0; i < errorVector.length; i++) {
         magnitude += errorVector[i] * errorVector;
     magnitude = Math.sqrt(magnitude);
     if (magnitude <= cSettings.noiseThreshold) {
     System.out.println("VSController: magnitude (of errorVector) = " + magnitude +
               ", threshold = " + cSettings.noiseThreshold); // Debug
Now here's my issue: I change the value for "noiseThreshold" in "ControllerSettings.java" then run make from terminal (makefile code posted below) and rerun "Simulation". However, despite my changes to "ControllerSettings.java" the value for "noiseThreshold" is not changed, as evidenced by the output on the terminal screen:VSController: magnitude (of errorVector) = 6.085046125925263, threshold = 10.0 See, that value of 10.0 is what I used to have for noiseThreshold. I do not know why this value does not update even though I save the java file and execute make in between executions of Simulation. I would love it if someone could explain this problem to me.
Here's the contents of makefile.
JFLAGS = -cp ../Jama\-1\.0\.2.jar:../utils/:/usr/share/java/vecmath\-1\.5\.2.jar:.
JC = javac
.SUFFIXES: .java .class
.java.class:
     $(JC) $(JFLAGS) $*.java
CLASSES = \
     ControllerSettings.java \
     ImageFeaturesData.java \
     KukaKR15SL.java \
     ../utils/KukaSendData.java \
     NGN.java \
     Puma560.java \
     Robot.java \
     RobotSettings.java \
     Simulation.java \
     SimulationSettings.java \
     SixRRobot.java \
     Targets.java \
     TargetsSettings.java \
     ThreeDData.java \
     ThreeDSensor.java \
     VSController.java
default: classes
classes: $(CLASSES:.java=.class)
clean:
     $(RM) *.classEdited by: raequin on Apr 5, 2010 1:43 PM

I saw this explanation about what's causing my problem.
"When the Java compiler sees a reference to a final static primitive or String, it inserts the actual value of that constant into the class that uses it. If you then change the constant value in the defining class but don't recompile the using class, it will continue to use the old value."
I verified that the value updates if I also change something in VSController.java, forcing it to recompile. I think I will solve this problem by just making the variables in ControllerSettings no longer final (and then recompile VSController to make sure it takes effect!). Is there another solution? I saw intern(), but that seems to only apply to Strings.
Thanks.

JMS multi thread best practise

Hi,
I would like to code a JMS layer that could be accessed by
a multi thread environment (a web app)
Is there any "Connection-Pool/DAO" equivalent design
pattern for JMS ?
Form what I know, connection are Thread Safe and Sessions
are not ...
Philippe

Many J2EE providers have their own JMS facades which provide pooling - so you could just use your container's JMS wrappers.
Another option, if you are inside a Servlet Engine, is to use Jencks which provides JMS & JDBC connection pooling as well as pooling of threads & message listeners & exception handling when consuming JMS messages.
e.g. here's inbound message consumption...
http://jencks.org/Message+Driven+POJOs
and here's outbound JMS (i.e. pooling when sending JMS messages etc)
http://jencks.org/Outbound+JMS
Jencks is basically a Spring based JCA container so it takes care of all the pooling for you as well as handling message inflow & outflow and can work with XA if you need it as well as local transactions.
James
http://logicblaze.com/

Oracle Multi-threaded libraries and Forte R3

Hello all,
I heard through the grapevine that it would be possible
to use Oracle 7.3 multi-threaded support with Forte 3.0G.
(thus making Load-Balancing obsolete in this case)
Has anyone given a try at this assumption ?
If yes, on what platform and what versions ?
Thanks,
Vincent Figari
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Hi,
It is available In R3.0.F.2 also. I tested it this release and it works
very well. But, you need to make a design pattern on it : A Oracle
Session can not be shared between several transactions throught threads.
So You need to manage a pool of DBSessions.
Hope this Helps,
Daniel Nguyen
Freelance Forte Consultant
Vincent R Figari wrote:
>
Hello all,
I heard through the grapevine that it would be possible
to use Oracle 7.3 multi-threaded support with Forte 3.0G.
(thus making Load-Balancing obsolete in this case)
Has anyone given a try at this assumption ?
If yes, on what platform and what versions ?
Thanks,
Vincent Figari
You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com
Or call Juno at (800) 654-JUNO [654-5866]
To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
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To unsubscribe, email '[email protected]' with
'unsubscribe forte-users' as the body of the message.
Searchable thread archive <URL:http://pinehurst.sageit.com/listarchive/>

Multi-threaded?

When a MessageListener is attached to a queue, are the messages received in multi-threaded mode? I have some global-variables to be taken care.
thanks for any help.

Message listeners have their own thread which is created for them by the client runtime.

Multi-Thread Messaging

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