Is the ThreadpoolExecutor thread safe?
Is the ThreadpoolExecutor thread safe? Is it safe to use a ThreadpoolExecutor from a multiple thread contexts?
If the API documentation says it's thread-safe, then it is. Otherwise you must assume it is not.
Similar Messages
-
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? -
Is the isReachable() thread safe ? How to approach it ?
I've created a ping class which uses InetAddress.isReachable().
I have 100 devices, with 100 threads which are using the ping object instances simultaneously.
When one device is not reachable ( it doesn't responde), the next 5 o 10 ping test fail as well.
I've read that isReachable is not thread safe, is this true ?
This is the code that performes the ping.
final long start = System.nanoTime();
if (InetAddress.getByName(sIp).isReachable(5000)) {
result=(System.nanoTime() - start) / 1000 / 1000;
} else {
result=-1;
Thanks for your help.I am not sure measuring the time in seconds will be very useful unless you are trying to detect very slow response times.
Do you investigate using broadcast pings i.e. it pings every box at once.
Why do you have such along timeout?
Even testing a box on the other side of the world on a decent WAN should be less than 400 ms.
What do you mean by the next 5 to 10? Do you mean in the same thread or between theads or is it that the boxes that timeout all have the same timeout so they fail at the same time? -
In the Java tutorial - Creating a GUI with JFC/Swing trail - the main methods consist of some code to make the application "thread safe" by scheduleing the job for the event-dispatching thread. I can only guess at the true meaning of this. Other Java books do not take this approach. I actually don't remember the tutoral saying that last time I looked at it (some time ago). I have been using the main method to set up my frame and add to it my GUI class. This seems to always work for me. What do other forum members do and recommend?
Whenever you write GUI code in Java, you (1) must ensure that changes to GUI objects only happen on the event thread, and (2) should schedule long-running operations on another thread.
The first rule is simple: GUI objects are not synchronized, and if you try to change one from outside the event thread it may have inconsistent internal state when the GUI thread tries to access it. "Change" may be as simple as setting the contents of a JTextfield, or as complex as rebuilding the model for a JTable.
If you simply create and display a JFrame from main(), you're generally safe. Until you call setVisible(true), the JFrame isn't actually accessed by the GUI thread. Once you call setVisible(true), the GUI thread takes control of the frame. If that's the last step in your main(), you're OK; for most complex programs, however, that's not the last step. As a result, it's a good habit to build up your frame from within a Runnable that you put on the event thread via SwingUtilities.invokeLater().
(This last recommendation is a new part of the tutorial. I think it was added as-of 1.5, when show() was deprecated in favor of setVisible(true)).
As long as your program simply reacts to events generated by your GUI programs, you don't have to worry about any other threads, since those events are distributed on the event thread. However, most real programs interact with the outside world: they read files, make database calls, access app-servers, or whatever. These calls all block the thread that's executing them; if you call them from the event thread, this will freeze your UI.
So, rule #2 says to execute those potentially blocking operations on another thread (it's a suggestion, rather than an absolute, because you're free to do everything on the event thread as long as you don't mind blocked apps -- most people do mind, however).
Of course, once you start something running on a separate thread, you need to get the results back to the event thread, which is where rule #1 (which is mandatory) comes in.
Sun provides the SwingWorker class to help you with this; you can find it linked from the tutorial. Personally, I don't like it (in part because it spins up a new thread for each operation); instead, I use an "AsynchronousOperation" class that I pass to a threadpool for execution. -
SSRS - Is there a multi thread safe way of displaying information from a DataSet in a Report Header?
In order to dynamically display data in the Report Header based in the current record of the Dataset, we started using Shared Variables, we initially used ReportItems!SomeTextbox.Value, but we noticed that when SomeTextbox was not rendered in the body
(usually because a comment section grow to occupy most of the page if not more than one page), then the ReportItem printed a blank/null value.
So, a method was defined in the Code section of the report that would set the value to the shared variable:
public shared Params as String
public shared Function SetValues(Param as String ) as String
Params = Param
Return Params
End Function
Which would be called in the detail section of the tablix, then in the header a textbox would hold the following expression:
=Code.Params
This worked beautifully since, it now didn't mattered that the body section didn't had the SetValues call, the variable persited and the Header displayed the correct value. Our problem now is that when the report is being called in different threads with
different data, the variable being shared/static gets modified by all the reports being run at the same time.
So far I've tried several things:
- The variables need to be shared, otherwise the value set in the Body can't be seen by the header.
- Using Hashtables behaves exactly like the ReportItem option.
- Using a C# DLL with non static variables to take care of this, didn't work because apparently when the DLL is being called by the Body generates a different instance of the DLL than when it's called from the header.
So is there a way to deal with this issue in a multi thread safe way?
Thanks in advance!
Hi Angel,
Per my understanding that you want to dynamic display the group data in the report header, you have set page break based on the group, so when click to the next page, the report hearder will change according to the value in the group, when you are using
the shared variables you got the multiple thread safe problem, right?
I have tested on my local environment and can reproduce the issue, according to the multiple safe problem the better way is to use the harshtable behaves in the custom code, you have mentioned that you have tryied touse the harshtable but finally got
the same result as using the ReportItem!TextBox.Value, the problem can be cuased by the logic of the code that not works fine.
Please reference to the custom code below which works fine and can get all the expect value display on every page:
Shared ht As System.Collections.Hashtable = New System.Collections.Hashtable
Public Function SetGroupHeader( ByVal group As Object _
,ByRef groupName As String _
,ByRef userID As String) As String
Dim key As String = groupName & userID
If Not group Is Nothing Then
Dim g As String = CType(group, String)
If Not (ht.ContainsKey(key)) Then
' must be the first pass so set the current group to group
ht.Add(key, g)
Else
If Not (ht(key).Equals(g)) Then
ht(key) = g
End If
End If
End If
Return ht(key)
End Function
Using this exprssion in the textbox of the reportheader:
=Code.SetGroupHeader(ReportItems!Language.Value,"GroupName", User!UserID)
Links belowe about the hashtable and the mutiple threads safe problem for your reference:
http://stackoverflow.com/questions/2067537/ssrs-code-shared-variables-and-simultaneous-report-execution
http://sqlserverbiblog.wordpress.com/2011/10/10/using-custom-code-functions-in-reporting-services-reports/
If you still have any problem, please feel free to ask.
Regards
Vicky Liu -
I am working on a lobby system with a chat are using Networking, and recently I noticed that occasionally my JTextArea does not append the data I give it, even if I have a System.out.println() directly before which shows me what it is being passed, and it is being passed correct Strings, it is just not appending them.
Thread updateText = new Thread() {
public void run()
for(;;)
try {
for (int x = 0; x < texts.size(); x++) {
System.out.println("ADDED: "+texts.get(x));
textArea.append(texts.get(x));
texts.clear();
scrollToEnd(textArea);
Thread.sleep(100);
} catch (InterruptedException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
};I have an ArrayList texts, which keeps track of what is being typed into the Chat Area. This code displays correctly What I want it to, i.e. "ADDED: Hello guys, etc.", however the JTextArea does not update. Is there something to make the JTextArea thread-safe because I have heard on several sites that JTextAreas are not thread-safe.
Any help would be greatly appreciated.I changed my code to this: and now it does not work at all, i.e., the JTextArea never updates:
Thread updateText = new Thread() {
public void run()
for(;;)
try {
SwingUtilities.invokeAndWait(update);
} catch (InterruptedException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
} catch (InvocationTargetException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
Runnable update = new Runnable() {
public void run()
try {
texts.clear();
scrollToEnd(textArea);
for (int x = 0; x < texts.size(); x++) {
System.out.println("ADDED: " + texts.get(x));
textArea.append(texts.get(x));
Thread.sleep(100);
} catch (InterruptedException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}; -
Are CacheStore's and BackingMapListener's thread safe?
I'm implementing a JMS CacheStore and have a quick question: does Coherence ever attempt to run multiple threads concurrently across a CacheStore instance on a given node?
Reason I ask is that only certain objects are thread-safe in the JMS spec.: Connection Factories, Destinations (i.e. a Queue) and Connections. However Sessions, Producers and Consumers are not.
In order to improve performance, it's recommended (obviously) to try and reuse Sessions/Producers and not recreate them for every message sent. So I'd like to declare them as instance variables in my class and assign them once-only at construction time.
I just wanted to make sure that this would be OK (i.e. Coherence would start multiple threads running across my CacheStore). Anyone any ideas?
(NB. I'm using JMS Connection Pooling to get around this issue at the moment - as the pools are thread-safe and I can close/open them quickly as many times as I like - but this is not a part of the JMS standard, so I end up using vendor-specific classes which I'd rather not do. Likewise I could make many of these non-thread-safe objects use ThreadLocals, but this all seems a bit overkill if it isn't actually required...)
An other issue... :)
What about closing the connection when it's finished with? Again, it's JMS recommended best-practice to do so. How is this best accomplished, seem as though it was Coherence that created the CacheStore instance and my client code has no reference to it? Best I can think of for now is have a static method in my CacheStore class that is kicked off via an invocation-service agent. Again, if anyone has a better idea I'm all ears.
An other issue... :)
Does the same thread-safety hit BackMapListeners? The "receiving" end of my JMS messages is a BackingMapListener based on the Incubator Commons "AbstractMultiplexingBackingMapListener" class. So, does Coherence ever kick off multiple threads across a single BackingMapListener instance, or can I safely have the JMS Session and Consumer left open after construction as class-level members?
Cheers,
Stevestevephe wrote:
True... But I was rather hoping I could just get someone from Oracle who wrote the stuff to comment instead! :) Don't really want to second-guess this, as there could always be unusual corner-cases that could be difficult to replicate. Still...
I did a bit more testing on my CacheStore this morning. I removed the non JMS-standard "pooling" and just created instance variables for only those items which I know to be thread-safe (ConnectionFactory, Connection and my target queue, a "Destination" in JMS terminology) I now re-get the Session and Producer in each Cachestore method. This makes the code thread-safe and portable. TBH, it hasn't affected performance too much, so I'll leave it as it is for now (and I've put a comment in the code stating that people could move these things to ThreadLocal's if they wanted to further boost performance in their own usage cases and still keep the CacheStore thread-safe.)
As regards the "receiving" end of these published messages, my BackingMapListener does nothing more than register a JMS MessageListener and a "connection.start()" call. This is a very short, one-off call, so shouldn't leave Coherence service threads "hanging" on anything for extended periods.
Cheers,
SteveHi Steve,
to cut things short:
1. Coherence instantiates one cache store per read-write-backing-map, therefore it needs to be thread-safe if you have a thread-pool or use write-behind.
2. If you don't have write-behind then Coherence uses the worker thread to execute the cache store operations.
3. If you have write-behind then generally Coherence uses the write-behind thread (this is a separate thread per write-behind-configured service) to execute the cache store operations, except for erase[All]() operations on cache.remove() or batch remove which cannot be delayed due to consistency reasons and are executed on the worker thread.
If you don't have a thread-pool, replace worker thread with service thread.
I don't know off my head where the refresh-ahead operation executes.
There is a single backing-map-listener per backing map instantiated, therefore it needs to be thread-safe. BackingMapManagerContext is thread-safe, so there is no issue with sharing it across multiple threads executing on a backing-map-listener.
Best regards,
Robert -
hello all,
please help me by answering these questions?
singleton patterns calls for creation of a single class that can be shared between classes. since one class has been created
Can singletons be used in a multithreaded environment? is singleton thread safe?
Are threading problems a consequence of the pattern or programming language?
thank you very much,
HiruHi,
Before explaining whether a singleton is thread safe
e i want to explaing what is thread safe here
When multiple threads execute a single instance of a
program and therefore share memory, multiple threads
could possibly be attempting to read and write to the
same place in memory.If we have a multithreaded
program, we will have multiple threads processing the
same instance.What happens when Thread-A examines
instance variable x? Notice how Thread-B has just
incremented instance variable x. The problem here is
Thread-A has written to the instance variable x and
is not expecting that value to change unless Thread-A
explicitly does so. Unfortunately Thread-B is
thinking the same thing regarding itself; the only
problem is they share the same variable.
First method to make a program threadsafe-: Avoidance
To ensure we have our own unique variable instance
for each thread, we simply move the declaration of
the variable from within the class to within the
method using it. We have now changed our variable
from an instance variable to a local variable. The
difference is that, for each call to the method, a
new variable is created; therefore, each thread has
its own variable. Before, when the variable was an
instance variable, the variable was shared for all
threads processing that class instance. The following
thread-safe code has a subtle, yet important,
difference.
second defense:Partial synchronization
Thread synchronization is an important technique to
know, but not one you want to throw at a solution
unless required. Anytime you synchronize blocks of
code, you introduce bottlenecks into your system.
When you synchronize a code block, you tell the JVM
that only one thread may be within this synchronized
block of code at a given moment. If we run a
multithreaded application and a thread runs into a
synchronized code block being executed by another
thread, the second thread must wait until the first
thread exits that block.
It is important to accurately identify which code
block truly needs to be synchronized and to
synchronize as little as possible. In our example, we
assume that making our instance variable a local
variable is not an option.
Third Defence:--Whole synchronization
Here u should implement an interface which make the
whole class a thread safe on or synchronized
Thre views are made by Phillip Bridgham, M.S., is a
technologist for Comtech Integrated Systems.I'm
inspired by this and posting the same hereWas there a point in all of that? The posted Singleton is thread-safe. Furthermore, some of that was misleading. A local variable is only duplicated if the method is synchronized, a premise I did not see established. Also, it is misleading to say that only one Thread can be in a synchronized block of code at any time because the same block may be using different monitors at runtime, in which case two threads could be in the same block of code at the same time.
private Object lock;
public void doSomething() {
lock = new Object();
synchronized(lock) {
// Do something.
}It is not guaranteed that only one Thread can enter that synchronized block because every Thread that calls doSomething() will end up synchronizing on another monitor.
This is a trivial example and obviously something no competent developer would do, but it illustrates that the statement assumes premises that I have not seen established. It would be more accurate to say that only one Thread can enter a synchronized block so long as it uses the same monitor.
It's also not noted in the discussion of local variables vs instance variables that what he says only applies to primitives. When it comes to actual Objects, just because the variable holding the reference is unique to each Thread does not make use of it thread-safe if it points to an Object to which references are held elsewhere. -
Need thread safe way to access read-only objects
I have been working on a lot of projects and all the developers agree that they want thread safe code when called by many threads. It's rare developers are making statement like: "Data are not corrupted often so don't bother" or "It's not thread safe, but that will not often create issues".
In TopLink client session itself is thread safe but not the persistent object themselves. Via client session, if you want thread safe access you need to put a lock on CacheKey and it's not a public/supported API. So the only thread safe access is via unit of work.
We would like fast access to objects. We have a batch process that just need read-only access to objects. We need to read via unit of work to get thread safe access. But we just need the clone when we read via unit of work, we don't need the backup for change detection.
However, TopLink doesn't have a mean to do that.
Please push implementation of Bug5998333[WANT THREAD SAFE AND CORRECT ISOLATION WITH OBJECTS FROM ADDREADONLYCLASS]
In Hibernate, by design, all access are always thread safe. Accessing read-only object just create one copy (a clone), no backup needed.
Oracle claims that TopLink is fast. I wonder if their performance testing code is thread safe, so access objects via unit of work or they take the shortcut of accessing objects from client session. Also, reliable performance comparison should use conform in unit of work.As you stated the UnitOfWork offers you your desired functionality, you would just like an improvement in performance.
In TopLink 10.1.3 (or 11g preview) you have a few options:
- Use a UnitOfWork an live with the slight overhead of the back copies (it will only add 5-30 % overhead to your processing)
- Instead use an isolated client session, this will not require any cloning or backup clones, but also does not allow any caching.
- Use change tracking, TopLink added attribute-level change tracking in 10.1.3, when used the UnitOfWork does not create backup clones. In 10.1.3 it was mainly used for CMP and requires code generation, but you could implement or weave the code yourself. In TopLink 11g, change tracking is weaved by default with JPA and the weaver can also be used with POJO objects.
I agree that having a feature to mark an object as transactionally read-only would be desirable, it seems like you have logged the enhancement. You could try escalting the enhancement through Oracle support, but since it is an enhancement and not a bug, it is probably beyond what support offers. You may wish to investigate services, or potentially join the open source Eclipse EclipseLink project which the next version of TopLink is being developed under and take part in the feature yourself. -
Is ThreadPoolExecutor.execute(Runnable) thread-safe?
Is ThreadPoolExecutor.execute(Runnable) thread-safe, i.e. is it safe
to invoke this method from multiple threads without making any
special arrangements to ensure that not more than one thread is
in the execute() method of the ThreadPoolExecutor object at the same time
(such as synchronizing on the ThreadPoolExecutor object)?
I can find nothing in the Java 6 documentation to say it is thread-safe
(Executor, ExecutorService, ThreadPoolExecutor and package documentation).
Note that I am not asking anything about the actual execution of the Runnables.
I am asking about the act of inserting the Runnables into the thread pool.Thanks to everyone who replied.
The three example implementations in the interface documentation for Executor, including the one where the Runnable is executed by the invoking thread, are thread-safe but only the last one needs to do anything special (namely make the execute(...) method synchronized) to be thread-safe. It is not clear whether the thread-safety of the first two implementations is conscious or accidental. Even if conscious that would not imply that it is necessary.
I think the published documentation (unless I've missed something) is deficient. The method would not be useless if not thread-safe. I don't think thread-safety is a safe default assumption. I think a package that supports concurrent programming should be clear on where it is thread-safe.
I've had a quick look at the source code in the 1.6 JDK implementation. It makes a serious and plausible effort to be thread-safe. It was written by Doug Lea.
I'm going to assume the method is thread-safe, based on looking at the source code. -
Is the Illustrator SDK thread-safe?
After searching this forum and the Illustrator SDK documentation, I can't find any references to a discussion about threading issues using the Illustrator C++ SDK. There is only a reference in some header files as to whether menu text is threaded, without any explanation.
I take this to mean that probably the Illustrator SDK is not "thread-safe" (i.e., it is not safe to make API calls from arbitrary threads; you should only call the API from the thread that calls into your plug-in). Does anyone know this to be the case, or not?
If it is the case, the normal way I'd write a plug-in to respond to requests from other applications for drawing services would be through a mutex-protected queue. In other words, when Illustrator calls the plug-in at application startup time, the plug-in could set up a mutually exclusive lock (a mutex), start a thread that could respond to requests from other applications, and request periodic idle processing time from the application. When such a request arrived from another application at an arbitrary time, the thread could respond by locking the queue, adding a request to the queue for drawing services in some format that the plug-in would define, and unlocking the queue. The next time the application called the plugin with an idle event, the queue could be locked, pulled from, and unlocked. Whatever request had been pulled could then be serviced with Illustrator API calls. Does anyone know whether that is a workable strategy for Illustrator?
I assume it probably is, because that seems to be the way the ScriptingSupport.aip plug-in works. I did a simple test with three instances of a Visual Basic generated EXE file. All three were able to make overlapping requests to Illustrator, and each request was worked upon in turn, with intermediate results from each request arriving in turn. This was a simple test to add some "Hello, World" text and export some jpegs,
repeatedly.
Any advice would be greatly appreciated!
Glenn Picher
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. -
Is the java 1.5 default SAXParser thread safe.
I used the following code to create a parser and validate my xml data.
But the following code is causing too many open file issue.
After doing some analysis I understood that each object of parser is open the file "file://var/app/bea/files/wfinf/xmlschema/WorkflowDecisionResponse.xsd".
So if I comment the setProperty method it will work fine.
My question is this parser is thread safe so that I can create single instance of parser and can be shared by all my thread?
If not can some body suggest a better idea to validate it.
public static boolean validate(String XMLData){
SAXParserFactory factory = SAXParserFactory.newInstance();
factory.setNamespaceAware(true);
factory.setValidating(true);
SAXParser parser = factory.newSAXParser();
parser.setProperty("http://java.sun.com/xml/jaxp/properties/schemaLanguage", "http://www.w3.org/2001/XMLSchema");
parser.setProperty("http://java.sun.com/xml/jaxp/properties/schemaSource", "file://var/app/bea/files/wfinf/xmlschema/WorkflowDecisionResponse.xsd");
try{
parser.parse(new InputSource(new StringReader(XMLData)), new DummyHandlerImpl());
}catch(Exception e) {
return false;
return true;
}Hi There,
I found this thread of yours with no reply from anybody.
I'm also facing a similar issue. Did you found a solution to this.
If yes please share.
Regards,
Mayank -
BC4J View not Thread safe, user sessions are using the same view instance
Hi There,
We are using BC4J that came with JDeveloper 10.1.2.0.0 with Oracle 10G 10.1.2.0.0.
I have an BC4J account search view (BC4J AccountSearchView) that users can call to search for an account. So this view could be used by numerous users and pieces of code at the same time. Now my understanding is that each user gets their own instance of the view so changing the view's query should not be an issue (since the view definition is not changing). Under a light load the account search view looks like everyone get there own instance of the view and there expected account search results. But under a heavy user load when we have User A and User B the search query that was for User A will be used by User B. So the user results for one user will get the other users results.
I do not understand if the view definition is been changed by the other user and is impacting all view instances. How can this occur if it is thread safe?
I have enclosed the core code for this search.
If you can help that would be much appreciated, thanks in advance,
Nigel
accountSearchView.setQuery(baseSelectQuery+generateWhereClause());
logger.debug("SearchAccounts Query: "+accountSearchView.getQuery());
System.out.println("SearchAccounts SQL: "+accountSearchView.getQuery());
accountSearchView.setPassivationEnabled(false);
accountSearchView.setForwardOnly(true);
accountSearchView.executeQuery();
get attributes for each row result and place in new Java bean objects and return to user.Nigel, we've only certified JDeveloper 10.1.2 against the Struts 1.1 with which it ships.
If there have been any changes in Struts 1.2 to the Struts Request Processor, then this could easily have an impact on the BC4JRequestProcessor's correct functioning, depending on what the changes were.
My quick look into the issue tells me that the ActionServlet init parameter named mapping in web.xml that we use for the 9.0.3-style BC4J/Struts integration is getting ignored by Struts 1.2. This parameter is used by Struts 1.1 to globally configure a custom ActionMapping subclass which can support additional properties. My quick test shows me that Struts 1.2 is ignoring this setting and so the oracle.jbo.html.struts11.BC4JActionMapping subclass of Struts's default ActionMapping is not getting used correctly as it does in Struts 1.1. This leads to errors when Struts tries to configure its actions in struts-config.xml since the Apache digester tries to set properties on the ActionMapping instance that don't exist (since the BC4JActionMapping has these properties, and it's not being used).
<servlet>
<servlet-name>action</servlet-name>
<servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
<init-param>
<param-name>mapping</param-name>
<param-value>oracle.jbo.html.struts11.BC4JActionMapping</param-value>
</init-param>
</servlet>This is my quick analysis of what's not out-of-the-box compatible. I don't know enough about the changes in Struts 1.2 to know why this Struts 1.1 feature broke in Struts 1.2, or what the Struts 1.2 way to accomplish the same thing is.
I'd encourage you to use Worldwide Support's Metalink site and open a TAR for any time-critical issues you need assistance in resolving. Many of us are constantly traveling and only able to sporadically chime in with tips in the forum as our time permits.
The source of the BC4JRequestProcessor ships with the produce in the ./BC4J/src directory inside the bc4jstrutssrc.zip file. -
How to know whether a method is thread-safe through the java-doc?
In some book, it says that SAXParserFactory.newSAXParser() is thread-safe,but in the java-doc,it doesn't say that.
newSAXParser
public abstract SAXParser newSAXParser()
throws ParserConfigurationException,
SAXExceptionCreates a new instance of a SAXParser using the currently configured factory parameters.
Returns:
A new instance of a SAXParser.
Throws:
ParserConfigurationException - if a parser cannot be created which satisfies the requested configuration.
SAXException - for SAX errors.
I want to know, how to know whether a method is thread-safe?System.out is a PrintStream object. None of the methods there use the synchronized modifier, but if you look in the source code, you will find out it is thread-safe, because it will use synchronized blocks whenever it writes some text.
The source code is in the src.jar file which you can extract.
I didn't find any comments about that PrintStream is thread-safe in the API.
Maybe you are looking for
-
HT1369 when syncing ipod, receiving blue screen error WDF_Violation
When syncing ipod, receiving blue screen error WDF_Violation
-
Losing network connection when loading new firmware from iTunes (or syncing
Noticed this when loading 1.1.1 weeks ago and now 1.1.2. Several times during the download/installation process, I lost my network connection. Rebooting the PC restored it, only to have it go down again, requiring another reboot. Required several PC
-
Unable to read sms in Nokia 5800
I bought a Nokia 5800 last year. It was working perfectly fine but since yesterday I am unable to read smses as when I click on the message, the touch is recognized but the message does not open. The new message notification as well as all the other
-
Import issue - folder view not refreshing
I found this old thread https://discussions.apple.com/message/3316449#3316449 that describes the problem I am having. The solution was to go into terminal but I don't know how to do that. Can someone please walk me thru it? Thanks a bunch!!!
-
Advanced Custom Field help. Need fiscal quarter/fiscal week.
A coworker is setting up an MS Project...project, and she asked for some help adding a custom field that would convert the Start date field into our Fiscal Quarter Fiscal Week schema, to display as FQFW, e.g. Q1W1. I've written a formula that accompl