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  • Java Executor: Small tasks or big ones?

    - by Arash Shahkar
    Consider one big task which could be broken into hundreds of small, independently-runnable tasks. To be more specific, each small task is to send a light network request and decide upon the answer received from the server. These small tasks are not expected to take longer than a second, and involve a few servers in total. I have in mind two approaches to implement this using the Executor framework, and I want to know which one's better and why. Create a few, say 5 to 10 tasks each involving doing a bunch of send and receives. Create a single task (Callable or Runnable) for each send & receive and schedule all of them (hundreds) to be run by the executor. I'm sorry if my question shows that I'm lazy to test these and see for myself what's better (at least performance-wise). My question, while looking after an answer to this specific case, has a more general aspect. In situations like these when you want to use an executor to do all the scheduling and other stuff, is it better to create lots of small tasks or to group those into a less number of bigger tasks?

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  • Accurately and securely measure the time spent viewing a web page

    - by balpha
    Suppose the following: You have a web page that presents a simple game to a user (e.g. a quiz, a puzzle, etc). The user solves the puzzle, submits the result, and you want to measure as precisely as possible how long they took to solve it. Assume it's quite simple, so we're talking seconds, not hours. Also assume JavaScript is required anyway, so there's no need to think of JS-disabled browsers. Finally, assume we don't want to use anything like Flash, Silverlight, or the like. I can think of several techniques: Simply take the time between the points when the data was sent from the server and when the submission arrives. Since this is exclusively server-side, there's no chance for cheating. However, issues like network latency and page rendering time might make this unfair for users with slow computers / browsers / internet connections. On the first request, just send the page without the actual game data. When everything is loaded so far, retrieve the game data through an AJAX call and populate it into the page. This is similar to 1., but reduces some of the caveats introduced through time spent on overhead. Have the time measured on the client side using JavaScript and submitted alongside with the solution. This would theoretically be the most accurate, but it introduces the possibility of cheating, because you're relying on client data. Use the request time headers of a "ready to play" AJAX call and the result submission request. Same caveat as 3., as it is still client data. A combination of server side and client side measuring with some kind of plausibility analysis. I can't think of a good way, but maybe you can. Thoughts? Other ideas?

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  • Is this a good starting point for iptables in Linux?

    - by sbrattla
    Hi, I'm new to iptables, and i've been trying to put together a firewall which purpose is to protect a web server. The below rules are the ones i've put together so far, and i would like to hear if the rules makes sense - and wether i've left out anything essential? In addition to port 80, i also need to have port 3306 (mysql) and 22 (ssh) open for external connections. Any feedback is highly appreciated! #!/bin/sh # Clear all existing rules. iptables -F # ACCEPT connections for loopback network connection, 127.0.0.1. iptables -A INPUT -i lo -j ACCEPT # ALLOW established traffic iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT # DROP packets that are NEW but does not have the SYN but set. iptables -A INPUT -p tcp ! --syn -m state --state NEW -j DROP # DROP fragmented packets, as there is no way to tell the source and destination ports of such a packet. iptables -A INPUT -f -j DROP # DROP packets with all tcp flags set (XMAS packets). iptables -A INPUT -p tcp --tcp-flags ALL ALL -j DROP # DROP packets with no tcp flags set (NULL packets). iptables -A INPUT -p tcp --tcp-flags ALL NONE -j DROP # ALLOW ssh traffic (and prevent against DoS attacks) iptables -A INPUT -p tcp --dport ssh -m limit --limit 1/s -j ACCEPT # ALLOW http traffic (and prevent against DoS attacks) iptables -A INPUT -p tcp --dport http -m limit --limit 5/s -j ACCEPT # ALLOW mysql traffic (and prevent against DoS attacks) iptables -A INPUT -p tcp --dport mysql -m limit --limit 25/s -j ACCEPT # DROP any other traffic. iptables -A INPUT -j DROP

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  • Creating C++ client app for some abstract windows server - how to manage TCP connection to server speed?

    - by Kabumbus
    So we have some server with some address port and ip. we are developing that server so we can implement on it what ever we need for help. What are standard/best practices for data transfer speed management between C++ windows client app and server (C++)? My main point is in how to get how much data can be uploaded/downloaded from/to client via his low speed network to my relatively super fast server. (I need it for set up of his live stream Audio/Video bit rate) My try on explaining number 3. We do not care how fast is our server. It is always faster than needed. We care about client tyring to stream out to our server his media. he streams encoded (via ffmpeg) live video data to our server. But he has say ADSL with 500kb/s of outgoing traffic. Also he uses some ICQ or what so ever so he has less than 500 kb/s per second. And he wants to stream live video! So we need to set up our ffmpeg to encode video with respect to the bit rate user can provide. We develop server side and client side. We need a way of finding out how much user can upload per second currently (so value can change dynamically over time)

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  • Git repos over multiple machines - backups and keeping in sync

    - by a-or-b
    I'm new to git so please feel free to RTFM me... I have multiple development sites (none of which can communicate via a network with each other) and am working on a few projects (with a few people) at any one time. What I would ideally have is at each site a centralized repository that can be pulled from but development would occur in our own (personal) repos. Then I would like to be able to sync across the centralized repos (via USB key for example). I want a centralized repo at each location as (1) I'm new to git and do break my (personal) local repo by playing around and (2) some projects get put on hold so I want to be able to free up disk space by deleting them. This is the "backup" part of my question. I was also hoping to be able to use 'git clone --bare' for my centralized repos (and the USB key repos to?) as we don't need the full checkout, just the git benefits. However I can't seem to get a bare repo to work as repo I can push from. I've used 'git remote' to set up an remote origin (similar to http://toolmantim.com/thoughts/setting_up_a_new_remote_git_repository) but I can't get 'git push' to work - it seems I need a checked-out repo. . Does anyone else use this sort of repo/development structure or is there something fundamental about git usage that I'm missing? . A solution that I thought about that might not work - If I had a 'git clone --bare' at each site and then use a git repo on my removable media which has remotes set up for each site then I could ('pull') sync my USB key with each repo. But then can I update the site repo from my USB key? Could I push from USB?

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  • HTML relative links on various domains

    - by Adam Kiss
    I have quickie: When you code/develop themes, how do you link to various files in your html/css code? Example: We at our firm use mostly <base target="http://whatever"> in our main template and then just <img src="./images/file.png"> in our html, "/category/page" as links and something alike in our css. However, when testing on different machines, we use ip address rather than localhost on main dev station of coder, so all base links don't work (because localhost goes to viewing machine, not coder's, in our network). Same thing happens when updating pages - on dev server, we have to edit base target, so browsing site won't take us to live site - this part is actually rather simple PHP (if ... echo else echo something else), but it still not solve problem of more coding-testing problems. So, my question is, how do YOU solve it? How do you use relative links, which basically don't care for what domain is the page on and don't care for url rewrite? (because ../images/ is different for / and different for /something/somethingElse/page)?

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  • Downloading a webpage in C# example

    - by Chris
    I am trying to understand some example code on this web page: (http://www.csharp-station.com/HowTo/HttpWebFetch.aspx) that downloads a file from the internet. The piece of code quoted below goes through a loop getting chunks of data and saving them to a string until all the data has been downloaded. As I understand it, "count" contains the size of the downloaded chunk and the loop runs until count is 0 (an empty chunk of data is downloaded). My question is, isn't it possible that count could be 0 without the file being completely downloaded? Say if the network connection is interrupted, the stream may not have any data to read on a pass of the loop and count should be 0, ending the download prematurely. Or does ResStream.Read stop the program until it gets data? Is this the correct way to save a stream? int count = 0; do { // fill the buffer with data count = resStream.Read(buf, 0, buf.Length); // make sure we read some data if (count != 0) { // translate from bytes to ASCII text tempString = Encoding.ASCII.GetString(buf, 0, count); // continue building the string sb.Append(tempString); } } while (count 0); // any more data to read?

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  • Connection Pool Strategy: Good, Bad or Ugly?

    - by Drew
    I'm in charge of developing and maintaining a group of Web Applications that are centered around similar data. The architecture I decided on at the time was that each application would have their own database and web-root application. Each application maintains a connection pool to its own database and a central database for shared data (logins, etc.) A co-worker has been positing that this strategy will not scale because having so many different connection pools will not be scalable and that we should refactor the database so that all of the different applications use a single central database and that any modifications that may be unique to a system will need to be reflected from that one database and then use a single pool powered by Tomcat. He has posited that there is a lot of "meta data" that goes back and forth across the network to maintain a connection pool. My understanding is that with proper tuning to use only as many connections as necessary across the different pools (low volume apps getting less connections, high volume apps getting more, etc.) that the number of pools doesn't matter compared to the number of connections or more formally that the difference in overhead required to maintain 3 pools of 10 connections is negligible compared to 1 pool of 30 connections. The reasoning behind initially breaking the systems into a one-app-one-database design was that there are likely going to be differences between the apps and that each system could make modifications on the schema as needed. Similarly, it eliminated the possibility of system data bleeding through to other apps. Unfortunately there is not strong leadership in the company to make a hard decision. Although my co-worker is backing up his worries only with vagueness, I want to make sure I understand the ramifications of multiple small databases/connections versus one large database/connection pool.

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  • c++ connect() keeps returning WSATIMEDOUT over internet but not localy

    - by KaiserJohaan
    Hello, For some reason, my chat application always gets WSATIMEDOUT when trying to connect to another person over the internet. int len_ip = GetWindowTextLength(GetDlgItem(hWnd,ID_EDIT_IP)); char ipBuffer[16]; SendMessage(GetDlgItem(hWnd,ID_EDIT_IP),WM_GETTEXT,16,(LPARAM)ipBuffer); long host_ip = inet_addr(ipBuffer); int initializeConnection(long host_ip, HWND hWnd) { // initialize winsock WSADATA wdata; int result = WSAStartup(MAKEWORD(2,2),&wdata); if (result != 0) { return 0; } // setup socket tcp_sock = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP); if (tcp_sock == INVALID_SOCKET) { return 0; } // setup socket address SOCKADDR_IN tcp_sock_addr; tcp_sock_addr.sin_family = AF_INET; tcp_sock_addr.sin_port = SERVER_TCP_PORT; tcp_sock_addr.sin_addr.s_addr = host_ip; // connect to server if (connect(tcp_sock,(SOCKADDR*)&tcp_sock_addr,sizeof(tcp_sock_addr)) == SOCKET_ERROR) { return 0; } HRESULT hr = WSAGetLastError(); // set socket in asynchronous mode if (WSAAsyncSelect(tcp_sock,hWnd,SOCKET_TCP, FD_READ | FD_WRITE | FD_CONNECT | FD_CLOSE) == SOCKET_ERROR) { return 0; } return 1; } For some reason it works perfectly fine on local network between computers, but totally screws up over the internet. WSATIMEDOUT is always returned (not connection refused, so its not a port problem). It makes me believe something is wrong with the IP but why on earth can it work on local addresses (like 192.168.2.4) Any ideas? Cheers

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  • Reporting Services "cannot connect to the report server database"

    - by Dano
    We have Reporting Services running, and twice in the past 6 months it has been down for 1-3 days, and suddenly it will start working again. The errors range from not being able to view the tree root in a browser, down to being able to insert parameters on a report, but crashing before the report can generate. Looking at the logs, there is 1 error and 1 warning which seem to correspond somewhat. ERROR:Event Type: Error Event Source: Report Server (SQL2K5) Event Category: Management Event ID: 107 Date: 2/13/2009 Time: 11:17:19 AM User: N/A Computer: ******** Description: Report Server (SQL2K5) cannot connect to the report server database. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. WARNING: always comes before the previous error Event code: 3005 Event message: An unhandled exception has occurred. Event time: 2/13/2009 11:06:48 AM Event time (UTC): 2/13/2009 5:06:48 PM Event ID: 2efdff9e05b14f4fb8dda5ebf16d6772 Event sequence: 550 Event occurrence: 5 Event detail code: 0 Process information: Process ID: 5368 Process name: w3wp.exe Account name: NT AUTHORITY\NETWORK SERVICE Exception information: Exception type: ReportServerException Exception message: For more information about this error navigate to the report server on the local server machine, or enable remote errors. During the downtime we tried restarting everything from the server RS runs on, to the database it calls to fill reports with no success. When I came in monday morning it was working again. Anyone out there have any ideas on what could be causing these issues? Edit Tried both suggestions below several months ago to no avail. This issue hasn't arisen since, maybe something out of my control has changed....

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  • Can i change the identity of the logged in user in ASP.net?

    - by Rising Star
    I have an ASP.net application I'm developing authentication for. I am using an existing cookie-based log on system to log users in to the system. The application runs as an anonymous account and then checks the cookie when the user wants to do something restricted. This is working fine. However, there is one caveat: I've been told that for each page that connects to our SQL server, I need to make it so that the user connects using an Active Directory account. because the system I'm using is cookie based, the user isn't logged in to Active Directory. Therefore, I use impersonation to connect to the server as a specific account. However, the powers that be here don't like impersonation; they say that it clutters up the code. I agree, but I've found no way around this. It seems that the only way that a user can be logged in to an ASP.net application is by either connecting with Internet Explorer from a machine where the user is logged in with their Active Directory account or by typing an Active Directory username and password. Neither of these two are workable in my application. I think it would be nice if I could make it so that when a user logs in and receives the cookie (which actually comes from a separate log on application, by the way), there could be some code run which tells the application to perform all network operations as the user's Active Directory account, just as if they had typed an Active Directory username and password. It seems like this ought to be possible somehow, but the solution evades me. How can I make this work?

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  • UnauthorizedAccessException when running desktop application from shared folder

    - by Atara
    I created a desktop application using VS 2008. When I run it locally, all works well. I shared my output folder (WITHOUT allowing network users to change my files) and ran my exe from another Vista computer on our intranet. When running the shared exe, I receive "System.UnauthorizedAccessException" when trying to read a file. How can I give permission to allow reading the file? Should I change the code? Should I grant permission to the application\folder on the Vista computer? how? Notes: I do not use ClickOnce. the application should be distributed using xcopy. My application target framework is ".Net Framework 2.0" On the Vista computer, "controlPanel | UninstallOrChangePrograms" it says it has "Microsoft .Net Framework 3.5 SP1" I also tried to map the folder drive, but got the same errors, only now the fileName is "T:\my.ocx" ' ---------------------------------------------------------------------- ' my code: Dim src As String = mcGlobals.cmcFiles.mcGetFileNameOcx() Dim ioStream As New System.IO.FileStream(src, IO.FileMode.Open) ' ---------------------------------------------------------------------- Public Shared Function mcGetFileNameOcx() As String ' ---------------------------------------------------------------------- Dim dirName As String = Application.StartupPath & "\" Dim sFiles() As String = System.IO.Directory.GetFiles(dirName, "*.ocx") Dim i As Integer For i = 0 To UBound(sFiles) Debug.WriteLine(System.IO.Path.GetFullPath(sFiles(i))) ' if found any - return the first: Return System.IO.Path.GetFullPath(sFiles(i)) Next Return "" End Function ' ---------------------------------------------------------------------- ' The Exception I receive: System.UnauthorizedAccessException: Access to the path '\\computerName\sharedFolderName\my.ocx' is denied. at System.IO._Error(Int32 errorCode, String maybeFullPath) at System.IO.FileStream.Init(...) at System.IO.FileStream..ctor(...) at System.IO.FileStream..ctor(String path, FileMode mode) ' ----------------------------------------------------------------------

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  • C# & SQL Server Authentication

    - by Peter
    Hello, I'm currently developing a C# app with an SQL Server DB back-end. I'm approaching the point of deployment and hitting a problem. The applicaiton will be deployed within an active directory network. As far as SQL authentication goes, I understand that I have 2 options - Windows Authenticaiton or Server Authenticaiton. If I use Server Authentication, I'm concerned that the username and password for the account will be stored in plain text in the app.config file, and therefore leave the database vulnerable. Using Windows Authenticaiton will avoid this issue, however it would mean giving every member of staff within our organisation read/write access to the database in order to run the app correctly. Whilst this is ok, it also means that they can easily connect to the database themselves via other means and directly alter the data outside of the app. I'm guessing there is someting really obvious I'm missing here, but I've been googling all evening to no avail. Any advice/guidance would be much appreciated! Peter Addition - my project is Windows Form based not ASP.NET - is encrypting the app.config file still the right answer? If it is, does anyone have any examples that are not ASP.NET based?

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  • Cross-platform general purpose C++ RPC library

    - by iUm
    Here's the task: Imagine, we have an applications and a plug-in for it (dynamic library). Interface between the application and the plug-in is completely defined. Now I need to run the application and the plug-in on different computers. I wrote a stub for the plug-in on a computer where the real applications is running. And the application loads it and calls its functions like if it were a native plug-in. On the other computer there's a stub instead of the real application, which loads the native plug-in. Now I need to organize RPCs between my stubs over the network, regardless the very transport. Usually, it's not difficult. But there're some restrictions: Application-plug-in interaction can be reenterable (e.g. application calls f1() from plug-in, in f1() plug-in calls g1() from application, in g1() application calls f2() from plug-in and so on...) Any such reenteration should be executed exactly by the same thread, which started the sequence Where can I find a cross-platform C++ RPC library with such features?

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  • .NET Remoting: Getting underlying socket?

    - by Alan
    Hi, I'm writing a light remoting app to assist in debugging a problem with remoting communication. This app mimics much of what a larger application does: Periodically sends a heartbeat to another peer application, and periodically verifies that a heartbeat has been received within some time threshold. What we're seeing is in our big application, the heartbeats seem to get dropped. One peer will go for long periods of time without seeing heartbeats from another peer, until the peer that is "dead" is restarted. The big application is responsive in all other ways. We believe it has something to do with the network setup. We were able to repro the problem locally, and fixed it by making some configuration changes to our test environment. To help our customer diagnose the issue, the mini-remoting app needs to log as much information as possible. So, is there a way to get the underlying socket for the remoting connection? I'm aware that I could write a custom sink for this, but I'd like to keep the actual remoting process as close to what is implemented in the big app as possible. Also as an aside, any ideas why the big-app might be "dropping" heartbeats?

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  • does entity framework or mysql provider swallows timeout exceptions on enumeration of result?!

    - by Freddy Rios
    I'm trying to make sense of a situation I have using entity framework on .net 3.5 sp1 + MySQL 6.1.2.0 as the provider. It involves the following code: Response.Write("Products: " + plist.Count() + "<br />"); var total = 0; foreach (var p in plist) { //... some actions total++; //... other actions } Response.Write("Total Products Checked: " + total + "<br />"); Basically the total products is varying on each run, and it isn't matching the full total in plist. Its varies widely, from ~ 1/5th to half. There isn't any control flow code inside the foreach i.e. no break, continue, try/catch, conditions around total++, anything that could affect the count. As confirmation, there are other totals captured inside the loop related to the actions, and those match the lower and higher total runs. I don't find any reason to the above, other than something in entity framework or the mysql provider that causes it to end the foreach when retrieving an item. The body of the foreach can have some good variation in time, as the actions involve file & network access, my best shot at the time is that when it takes beyond certain threshold there is some type of timeout in the underlying framework/provider and instead of causing an exception it is silently reporting no more items for enumeration. Can anyone give some light in the above scenario and/or confirm if the entity framework/mysql provider has the above behavior?

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  • asp.net 3.5 app - can not load asemblies, "Strong name signature could not be verified", only when d

    - by hitsolutions
    Have developed an asp.net 3.5 application which consists of a we-site, some developed assemblies and some 3rd party assembles such as Telerik, Jayrock etc, all very much standard 3rd party apps. Created and built this app, tested on Win 2008 Eval running on a VM, all fine. Imagine my frustration when after installing on clients production Win 2008 server, that the app could not run and the error message was the "Strong name signature could not be verified. The assembly may have been tampered with, or it was delay signed ..." one. This was for all assembles in app (removed one and this kept popping up for a different assembly). Attempted to install on a machine on the network and received the same error. I am fairly baffled and a little freaked as I can not figure this out and time is rapidly running out. Have inspected all parts of server I know about (.NET, IIS7) but all seems fine. What could cause this? It sounds like there is a stricter security manifest on the production server - but where would I look and for what? It must be a group policy. only other item is that the machines are running Symantec ante-virus. The IT head is on hols so can't quiz him which is also frustrating - but as they say time waits for no man!

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  • Firefox extension js object initialization

    - by Michael
    Note: this is about Firefox extension, not a js general question. In Firefox extension project I need my javascript object to be initialized just once per Firefox window. Otherwise each time I open my window a new timers will be engaged, new properties will be used, so everything will start from scratch. hope example below will demystify my question :) var StupidExtension { statusBarValue: "Not Initialized Yet", startup: function () { ... // Show statusBarValue in Status Bar Panel }, initTimerToRetrieveStatusBarValueFromNetwork: function () { ... } } so each time you hit Ctrl+N a new window you will see "Not Initialized Yet" and then new timer will be fired, so after some time it retrieve data from network you will see value also on second window and so on. Ideally would be to have just a single timer function running and updating all status bar panels in all Firefox windows. Of course I can do some caching, like saving the value in prefs or some other storage, then show it from there. But I feel like this is artificial. So the question will be is there "native" technique of making static some parts of the object among all Firefox window instances?

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  • Java "Pool" of longs or Oracle sequence with reusable values

    - by Anthony Accioly
    Several months ago I implemented a solution to choose unique values from a range between 1 and 65535 (16 bits). This range is used to generate unique Route Targets suffixes, which for this customer massive network (it's a huge ISP) are a very disputed resource, so any free index needs to become immediately available to the end user. To tackle this requirement I used a BitSet. Allocate on the RT index with set and deallocate a suffix with clear. The method nextClearBit() can find the next available index. I handle synchronization / concurrency issues manually. This works pretty well for a small range... The entire index is small (around 10k), it is blazing fast and can be easy serialized into a Blob field. The problem is, some new devices can handle RTs of 32 bits (range 1 / 4294967296). Which can't be managed with a BitSet (it would, by itself, consume around 600Mb, plus be limited to int range). Even with this massive range available, the client still wants to free available Route Targets for the end user, mainly because the lowest ones (up to 65535) - which are compatible with old routers - are being heavily disputed. Before I tell the customer that this is impossible and he will have to conform with my reusable index for lower RTs (up to 65550) and use a database sequence for the other ones (which means that when the user frees a Route Target, it will not become available again). Would anyone shed some light? Maybe some kind soul already implemented a high performance number pool for Java (6 if it matters), or I am missing a killer feature of Oracle database (11R2 if it matters)... Wishful thinking. Thank you very much in advance.

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  • MouseListener fired without checking JCheckBox

    - by Morinar
    This one is pretty crazy: I've got an AppSight recording (for those not familiar, it's a recording of what they did including keyboard/mouse input + network traffic, etc) of a customer reproducing a bug. Basically, we've got a series of items listed on the screen with JCheckBox-es down the left side. We've got a MouseListener set for the JPanel that looks something like this: private MouseAdapter createMouseListener() { return new MouseAdapter(){ public void mousePressed( MouseEvent e ) { if( e.getComponent() instanceof JCheckBox ) { // Do stuff } } }; } Based on the recording, it appears very strongly that they click just above one of the checkboxes. After that, it's my belief that this listener fired and the "Do stuff" block happened. However, it did NOT check the box. The user then saw that the box was unchecked, so they clicked on it. This caused the "Do stuff" block to fire again, thus undoing what it had done the first time. This time, the box was checked. Therefore, the user thinks that the box is checked, and it looks like it is, but our client thinks that the box is unchecked as it was clicked twice. Is this possible at all? For the life of me, I can't reproduce it or see how it could be possible, but based on the recording and the data the client sent to the server, I can't see any other logical explanation. Any help, thoughts, and or ideas would be much appreciated.

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  • Suggestions on writing a TCP IP messaging system (Client/Server) using Delphi 2010

    - by Shane
    I would like to write a messaging system using TCP IP in Delphi 2010. I would like to hear what my best options are for using the standard delphi 2010 components/indy components for doing this. I would like to write a server which does the listening and forwarding of messages to all machines on the network running a client. 1.) a.) clients can send a message to server to be forwarded to all other clients b.) clients listen for messages from other senders (via server) and displays messages. 2.) a.) Server can send a message to all clients b.) Server forwards any messages from clients to all other clients thanks for any suggestions NOTE: I am not writing a instant messaging or chat program. This is merely a system where users can send alerts/messages to other users - they can not reply to each other! NO commercial, shareware, etc links - please! I would like to hear about how you would go about writing this type of system and what approachs you would take, and possibly the TCP IP messaging architecture you would use. Whether it be straight Winows API, Indy components, etc, etc.

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  • CoreMidi _MIDINetworkNotificationContactsDidChange symbol not found

    - by Domestic Cat
    I'm getting the following error after a crash in an iPad app that uses CoreMIDI (The * are to blank out the app name): Dyld Error Message: Symbol not found: _MIDINetworkNotificationContactsDidChange Referenced from: /var/mobile/Applications/8F08B78E-929D-4C5A-9F02-08FD5743C17F/***.app/*** Expected in: /System/Library/Frameworks/CoreMIDI.framework/CoreMIDI in /var/mobile/Applications/8F08B78E-929D-4C5A-9F02-08FD5743C17F/***.app/*** Dyld Version: 179.4 When the app launches, I listen for MIDI Network Sessions using [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sessionDidChange:) name:MIDINetworkNotificationSessionDidChange object:nil]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sessionDidChange:) name:MIDINetworkNotificationContactsDidChange object:nil]; Which seems to be what is causing the crash. This is after I call session = [MIDINetworkSession defaultSession]; session.enabled = YES; session.connectionPolicy = MIDINetworkConnectionPolicy_Anyone; MIDIClientCreate(CFSTR("MidiManager"), midiNotifyProc, (void*)self, &midiClientRef); This kind of looks like CoreMIDI library has not been included in the build. Problem is, it IS included in the build as a required framework. (And the deployment target is set to 4.2). I can run the build fine on my iPad and have been testing extensively with other users' iPads also with no problems whatsoever. Also, this is an update to an existing app that has had several updates already with no problems. I just double checked my deployment build and the framework is definitely included, and I just installed that build onto my iPad (with a different provisioning profile from the store) and it works fine also. What could be happening? Could it be that Xcode just did a bad build for the one I sent to Apple, or am I missing something obvious? Could I change the MIDINetworkNotificationSessionDidChange notification symbol to a literal string (@"MIDINetworkNotificationSessionDidChange") to fix things for the mean time? Thanks for any help!

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  • Integrated Windows authentication in IIS causing ADO.NET failure

    - by TrueWill
    We have a .NET 3.5 Web Service running under IIS. It must use identity impersonate="true" and Integrated Windows authentication in order to authenticate to third-party software. In addition, it connects to a SQL Server database using ADO.NET and SQL Server Authentication (specifying a fixed User ID and Password in the connection string). Everything worked fine until the database was moved to another SQL Server. Then the Web Service would throw the following exception: A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) This error only occurs if identity impersonate is true in the Web.config. Again, the connection string hasn't changed and it specifies the user. I have tested the connection string and it works, both under the impersonated account and under the service account (and from both the remote machine and the server). What needs to be changed to get this to work with impersonation?

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  • Strategies for Synchronizing Data Between a Rails App and iPhone App

    - by jessecurry
    I've written many iPhone Applications that have pulled data from web services and I've worked on synchronizing data between an iPhone App and a Web Application, but I've always felt that there is probably a better way to handle the synchronization. I'd like to know what strategies you have used to synchronize data between your iPhone(read: mobile) Apps and your Rails(read: web) Applications. Are there any strategies that scale particularly well? How have you dealt with large amounts of data? (Do you use paged responses?) How do you make sure that data is not overwritten? Is there a reason to avoid Ruby on Rails? if so, can you suggest an alternative? What is better about the alternative? What strategies have failed? Why do you believe that those strategies failed? I would like to be able to keep all of the data modifications on the server, but the particular application I am about to start work on will need the ability to operate while disconnected from the network. The user will be able to update data on the mobile device and update data through the web application. When the user's mobile device connects to the server any local changes will be pushed to the server.

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  • How to control virtual memory management in linux?

    - by chmike
    I'm writing a program that uses an mmap file to hold a huge buffer organized as an array of 64 MB blocks. The blocks are used to aggregate data received from different hosts through the network. As a consequence the total data size written in each block is not known in advance. Most of the time it is only 2MB but in some cases it can be up to 20MB or more. The data doesn't stay long in the buffer. 90% is deleted after less than a second and the rest is transmitted to another host. I would like to know if there is a way to tell the virtual memory manager that ram pages are not dirty anymore when data is deleted. Should I use mmap and munmap when a block is used and released to control the virtual memory ? What would be the overhead of doing this ? Also, some colleagues expressed concerns about the performance impact of allocating such a big mmap space. I expect it to behave like a swap file so that only dirty pages are to be considered.

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