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• a completely decoupled OO system ?

  - by shrini1000

  To make an OO system as decoupled as possible, I'm thinking of the following approach: 1) we run an RMI/directory like service where objects can register and discover each other. They talk to this service through an interface 2) we run a messaging service to which objects can publish messages, and register subscription callbacks. Again, this happens through interfaces 3) when object A wants to invoke a method on object B, it discovers the target object's unique identity through #1 above, and publishes a message on the message service for object B 4) message services invokes B's callback to give it the message 5) B processes the request and sends the response for A on message service 6) A's callback is called and it gets the response. I feel this system is as decoupled as practically possible, but it has the following problems: 1) communication is typically asynchronous 2) hence it's non real time 3) the system as a whole is less efficient. Are there any other practical problems where this design obviously won't be applicable ? What are your thoughts on this design in general ?

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• MySQL IDE recommendation?

  - by Maxim Veksler

  Hello, I've been wondering what you guys are using to write,debug,test your SQL queries there days? The requirements are quite simple: Auto-complete Syntax Highlighting SQL Hisotry Good UI There are some tools which are common for this task, each with his own problems. To name a few Mysql Query Browser MySQL Workbench (GA?, Beta?) Eclipse Database development perspective Oracle SQL Developer with Connector/J I won't go into why none of them is perfect, trust me they all have their problems. So, what are you guys using?

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• ClickOnce deployment with VS2008 - prerequisites not installing on Windows 7 (only)

  - by dataft

  I have a VS2008 clickonce application with a custom prerequiste, which I install with the bootstrapper. When deployed online, the prerequisite is downloaded and installed fine. No problems. When deployed via CD to a Windows XP machine, also fine as above. No problems. However, when deployed via CD to a Windows 7 machine: the prerequisite is downloaded - good then the user is asked for permission to the run the file - good then the installation of the prerequiste is just SKIPPED - bad and the ClickOnce application installation begins without the prerequisite - bad Has anyone encountered this weird behaviour? I cannot find a solution anywhere.

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• How I can I get my home network's IP address from a shell script?

  - by Steven Stewart-Gallus

  I have an account at a server at school, and a home computer that I need to work with sometimes. I have exchanged keys, and now only have one problem. While my school account has a name associated with it, "account_name@school", my home network does not. My plan is to have a script that every hour retrieves my home network's IP address, ssh'es into my school account and updates my ssh config file storing my home network's IP address. How can I retrieve my home computer's IP address from a shell script? P.S. Is this a sensible plan?

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• how to create a telnet connction in delphi applications

  - by Monica

  i want to create a telnet connection in delphi that will allow me to connect to the command prompt on my computer.

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• How do I generate (and label) a random integer with python 3.2?

  - by An hero

  Okay, so I'm admittedly a newbie to programming, but I can't determine how to get python v3.2 to generate a random positive integer between parameters I've given it. Just so you can understand the context, I'm trying to create a guessing-game where the user inputs parameters (say 1 to 50), and the computer generates a random number between the given numbers. The user would then have to guess the value that the computer has chosen. I've searched long and hard, but all of the solutions I can find only tell one how to get earlier versions of python to generate a random integer. As near as I can tell, v.3.2 changed how to generate and label a random integer. Anyone know how to do this? Thanks!

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• Efficient algorithm to distribute work?

  - by Zwei Steinen

  It's a bit complicated to explain but here we go. We have problems like this (code is pseudo-code, and is only for illustrating the problem. Sorry it's in java. If you don't understand, I'd be glad to explain.). class Problem { final Set<Integer> allSectionIds = { 1,2,4,6,7,8,10 }; final Data data = //Some data } And a subproblem is: class SubProblem { final Set<Integer> targetedSectionIds; final Data data; SubProblem(Set<Integer> targetedSectionsIds, Data data){ this.targetedSectionIds = targetedSectionIds; this.data = data; } } Work will look like this, then. class Work implements Runnable { final Set<Section> subSections; final Data data; final Result result; Work(Set<Section> subSections, Data data) { this.sections = SubSections; this.data = data; } @Override public void run(){ for(Section section : subSections){ result.addUp(compute(data, section)); } } } Now we have instances of 'Worker', that have their own state sections I have. class Worker implements ExecutorService { final Map<Integer,Section> sectionsIHave; { sectionsIHave = {1:section1, 5:section5, 8:section8 }; } final ExecutorService executor = //some executor. @Override public void execute(SubProblem problem){ Set<Section> sectionsNeeded = fetchSections(problem.targetedSectionIds); super.execute(new Work(sectionsNeeded, problem.data); } } phew. So, we have a lot of Problems and Workers are constantly asking for more SubProblems. My task is to break up Problems into SubProblem and give it to them. The difficulty is however, that I have to later collect all the results for the SubProblems and merge (reduce) them into a Result for the whole Problem. This is however, costly, so I want to give the workers "chunks" that are as big as possible (has as many targetedSections as possible). It doesn't have to be perfect (mathematically as efficient as possible or something). I mean, I guess that it is impossible to have a perfect solution, because you can't predict how long each computation will take, etc.. But is there a good heuristic solution for this? Or maybe some resources I can read up before I go into designing? Any advice is highly appreciated!

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• C++ networking simple send and receive

  - by Wallter

  I'm trying to link 10 computers together, the program i would like to write would have one 'control' computer. From what I've looked up this computer would take all the packets sent over the network and do a echo with them... right? The other computers would need to be able to send information (then echoed to the others) to the 'control' ... is there a easy! or simple way to do this? From what I've seen i want a non-blocking socket? I have looked into sockets and such but for an armature programmer like me, this seems like a daunting task :) I'm kind-of looking for an easy class implication that has a send() and an event driven recv(). I'm not going to be sending that much information over the network.

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• How do I make a background thread in Java that allows the main application to exit completely? This

  - by Bob

  I have a Java application that creates a new thread to do some work. I can launch the new thread with no problems. When the "main" program terminates, I want the thread I created to keep running - which it does... But the problem is, when I run the main application from Eclipse or from Ant under Windows, control doesn't return unless the background process is killed. If I fork the main java process in ant, I want control to return to ant once the main thread is done with its work... But as it is, ant continues to wait until both the main process and the created thread are both terminated. How do I launch the thread in the background such that control will return to ant when the "main" application is finished? (By the way, when I run the same application under Linux, I am able to do this with no problems).

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• CVS in cmd/gui works only the third time I run a command.

  - by Somebody still uses you MS-DOS

  I'm using CVS in the command line. I'm in my repository folder. When I call a CVS command, I get... cvs [log aborted]: unrecognized auth response from localhost: -f [pserver aborted]: /opt/cvs/XXXXXX: no such repository ...2 times. The third time I run the command, it works with no problems. I tried to use a GUI client (CrossVC) and the same problem occurs. I tried inside gVim and Vim using VCSCommand and I'm having the same issues as well. I've tested with different times between each command, but I still have the same problems. I'm using a CVS configuration with stunnel. Why am I having problem with this setup? Why every time just the third time that I try to run the command that actually works?

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• Consuming Web Service via Windows Authentication

  - by saravanaram

  I am just trying to consuming a web service in remote computer using windows authentication however login credentials are different in local & remote computer. Code Snippet: Dim objproxy As New WebReference.Service1 'Create a new instance of CredentialCache. Dim mycredentialCache As CredentialCache = New CredentialCache() 'Create a new instance of NetworkCredential using the client Dim credentials As NetworkCredential = New NetworkCredential("username", "pwd","domain") 'Add the NetworkCredential to the CredentialCache. 'mycredentialCache.Add(New Uri(objproxy.Url), "Basic", credentials) objproxy.Credentials = credentials It is timing out but when i use mycredentialCache.Add(New Uri(objproxy.Url), "Basic", credentials) I get "401 Unauthorized" message, Please assist.

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• APC not recommended for production?

  - by solomongaby

  I have started having problems with my VPS in the way that it would faill to serve the pages on all the websites. It just showed a blank page, or offered to download the php file ( luckily the code was not in the download file :) ). The server was still running, but this seemed to be a problem with PHP, since i could login into WHM. If i did a apache restart, the sites would work again. After some talks with the server support they told me this is a problem with the APC extension witch they considered to be old and not recommended for production servers. So they removed it for now, to see if the same kind of fails would continue to appear. I haven't read anywhere that APC could have some problems or that its not always recommended to use, quite the contrary ... everywhere people are saying to always use it. The APC extension was installed ssh and is the latest version. Edit: They also dont recomend MemCache and say that a more reliable extension would be eAccelerator

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• why don't more programming languages have builtin interfaces to the window manager?

  - by Naveen

  Programming is at the heart about automating tasks on a computer. Presumably those tasks would normally be done manually by a human. Humans use the computer through the keyboard, mouse, and interaction with the console or the window manager. But very few languages have built in functions that provide an interface to these basic computing objects. A notable exception is autohotkey, an open source language on windows, providing builtin functions that allow the following simple tasks: * Get Pixel Information * Get mouse position * Keyboard macros * Simulate key strokes * Simulate mouse click * Window management See examples on rosettacode. There have been various attempts on linux, many of which were stopped without explanation. One is the inactive tcl library: android. Search google code for android, lang:tcl

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• Have you ever derived a programming solution from nature?

  - by Ryu

  When you step back and look at ... the nature of animals, insects, plants and the problems they have organically solved perhaps even the nature and balance of the universe Have you ever been able to solve a problem by deriving an approach from nature? I've heard of Ant Colony Algorithms being able to optimize supply chain amongst other things. Also Fractal's being the "geometry of nature" have been applied to a wide range of problems. Now that spring is here again and the world is coming back to life I'm wondering if anybody has some experiences they can share. Thanks PS I would recommend watching the "Hunting the Hidden Dimension" Nova episode on fractals.

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• Virus - How much it can affect?

  - by Sarang

  In our daily life, we come across various Viruses. In this internet world, we do have lots of type of viruses come to visit us ! While for the beginners, Virus is a complicated matter to fight with. Please explain the way how the virus come flow across the PC using Internet. What are the ways to search for them in the Personal Computer ? Also, we do have various solutions available in the market of Anti-Viruses, but also have different comments available for different software. Which is actually, really a useful Anti-Virus in the market that can give reliable performance ? Every Personal Computer connected to internet has to face against the viruses. Isn't there any general solution using Internet itself through which all networked computers get protected against Viruses ? Please give any solution.

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• Tomcat servlet-api.jar problem

  - by CitadelCSCadet

  I am running a web application using Tomcat and Java Servlets, JSP's, etc. I am aware that in order to use Servlets, it is dependent on the Servlet-api.jar file. Initially I placed this jar file in the WEB-INF/lib/ directory. This has worked fine for me for months during the developmental phase. When we put the application onto the server space we are using, we started seeing wierd problems showing up in the Catalina.out file telling us that there was dependency problems with the servlet-api.jar file. I am aware that tomcat has this jar file in its container, and that I should remove it from the WEB-INF/lib/ directory. I have tried this and it does not work. What do I have to do when I remove this jar file from the local files and allow it to depend on tomcats servlet-api.jar file.

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• How to handle recurring execution?

  - by ShaneC

  I am trying to validate the solution I came up for what I think is a fairly typical problem. I have a service running and every 10 minutes it should do something. I've ended up with the following: private bool isRunning = true; public void Execute() { while(isRunning) { if(isRunning) { DoSomething(); m_AutoResetEvent.WaitOne(new Timespan(0, 10, 0)); } } } public void Stop() { isRunning = false; m_AutoResetEvent.Set(); } The immediate potential problems I can see is that I'm not doing any sort of locking around the isRunning modification in Stop() which gets called by another thread but I'm not sure I really need to? The worst that I think could happen is that it runs one extra cycle. Beyond that are there any obvious problems with this code? Is there a better way to solve this problem that I'm unaware of?

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• Send and receive data trough the power network

  - by luvieere

  I'm not interested in a hardware solution, I want to know about software that may "read" modulated signal received trough the power supply - some sort of a low-level driver that would access the power signal in a convenient place and demodulate it. Is there a way to receive signal from the computer's power supply? I'm interested in an API or library that would allow the computer to be seen as a node in a Power Line Communication network and receive data directly through the power cable, without the need for a converter. Is there any active research in this field? Edit: There is software that reads monitors and displays internal component voltages - DC voltage after being converted and filtered by the power supply - now I need is a method of data encoding that would be invariant to conversion and filtering, the original signal embedded in AC being present in some form within the converted DC signal.

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• Dynamic Programming resources in C?

  - by EsotericMe

  Hi everyone, I'll be writing the online Google test tomorrow as a fresher. Apparently, they definitely ask one problem on Dynamic Programming? Does anyone know of a good resource for collection of DP problems in C along with solutions? I know what DP is & have used it on an occasion or twice. However I feel to crack a DP problem in test, prior practice of typical problems will make it easier to approach. Any good resources or problem sets with solutions in C will be highly appreciated. Thanks.

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• Programming cookbook? [closed]

  - by user73669

  Possible Duplicate: What is the single most influential book every programmer should read? Hello With sites like The Daily WTF and recurring threads on Slashdot and elsewhere about bad programming, I figured that, to avoid people reinventing the wheel (badly or not), there should be a good, fat book on programming that would go through typical programming problems and show good, known algorithms, either in pseudo-code or some language with an easy syntax so that the language is not an issue. Here's the list of books on the subject I saw at my local computer bookstore. Can you recommend a couple, or add to this list if it's missing better options? The art of computer programming Code complete Masterminds of programming 97 things every programmer should know The passionate programmer Pragmatic thinking & learning Coders at work The algorithm design manual Algorithms and programming How to think about algorithms How to think like a programmer Why programs fail Beautiful data Beautiful code The productive programmer Solid code Write great code Clean code Programming language pragmatics Hello world Learning Processing Learn to program Thank you.

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• Google Pie Chart and Bar Chart (both Interactive) not showing labels.

  - by iRubens

  I'm trying to put Google's BarChart and PieChart both the client side version, and i'm experiencing some problems with the labels over the pie and the labels on the left of the vertical axis (of the bar chart). I checked the code a lot of times and it seems to be like that you can see in the examples. I've tried the same page on Firefox and Chrome and it shows the labels without problems. If i try the examples on IE8 the labels are shown but not in my page. Sincerely I've not any idea where to start to fix this thing. Someone can help me or give me an advice? Thanks in advance.

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• How do I add "Press any key to boot from usb" when installing Windows from a flash drive? (Grub4dos question / how to remove a bootloader)

  - by Vincent

  Hi there! I've been struggling with this problem for a while now and finially decided to ask for help. Let me first explain what the main purpose of the app is: to provide the a very easy to use way of backing up files, after which I format the drive and start Windows 7 setup. I do this by booting WinPE, which runs a script to detect Windows installations and then opens a file browser. After the file browser is closed, the script continues and formats the drive that contains the Windows installation, and starts an unattended Windows 7 install. Now here is the problem: When you start Windows setup or WinPE from a dvd, you get a nice option to "Press any key to boot from DVD". This is to prevent the computer from booting the DVD when the first phase of the installation is complete and the computer reboots. However, when booting from a flash drive, Windows does not provide this option: it simply boots the flash drive every reboot. To replicate the "press any key" function, I installed Grub4Dos, which works great. It provides a small menu, the first standard item being "Continue installation", the second being "start installation". After quite a lot of tweaking, I got everything working: Start installation starts WinPE, which in turn starts the Windows installation. At first reboot, the Grub4Dos menu comes up, counts 5 seconds and boots the second stage of the installation. Here, I am greeted with the error: "Windows setup could not configure windows to run on this computer's hardware." When I boot into WinPE the normal way (put the bootmgr on the stick root) and change my bios to boot from the primary hdd after first reboot, I don't get this error. I've been looking around, and the only thing I could find was that the BIOS automatically names the boot device hd0, and that Windows can only be run / installed to hd 0. I'm not sure if this is the problem. I read about remapping to solve this problem, but to do that you have to know the phisical location of the hard drive and partition, like hd(0,1). I want this flash drive to work on any PC, regardless of where the OS is installed, so that's not really a possibility. A possible fix I thought of is removing the bootloader from the flash drive when I'm in WinPE. That way, when the pc reboots the BIOS will not see the flash drive as a boot drive and instead boot the primary hdd. I have yet to find a way to do this. Thank you for reading my question, and if you have any suggestion, please do.

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• How to determine the port numbers for peripheral devices?

  - by smwikipedia

  I know that peripheral devices such as a hard driver, a floppy driver, etc are controlled by reading/writing certain control registers on their device controllers. I am wondering about the following questions: Is it true that when these peripheral devices are plugged onto the computer, the addresses(port numbers) of their control registers are thus determined by how they are attached to the address bus (i.e. the hard-wiring rules, not any soft things)? Who makes the scheme of the port number assignment? If I was given a naked computer(with no operating system and with many peripheral devices), how could I figure out the port number assignment so I can use them to control peripheral deveices. At last and as usual, thanks for your patience and reply. 8^)

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• Making Django ignore string literals

  - by James

  UPDATE: It turns out this is a deeper question than I thought at first glance - the issue is that python is replacing the string literals before they ever get to django. I will do more investigating and update this if I find a solution. I'm using django to work with LaTeX templates for report generation, and am running into a lot of problems with the way Django replaces parts of strings. Specficially, I've run into two problems where I try to insert a variable containing latex code. The first was that it would replace HTML characters, such as the less than symbol, with their HTML codes, which are of course gibberish to a LaTeX interpreter. I fixed this by setting the context to never autoescape, like so: c = Context(inputs) c.autoescape = False However, I still have my second issue, which is that Django replaces string literals with their corresponding characers, so a double backslash becomes \, and \b becomes a backspace. How can I force Django to leave these characters in place, so inputs['variable'] = '{\bf this is code} \\' won't get mangled when I use {{variable}} to reference it in the django template?

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• Building SL4 + RIAServices app takes too long on VS2010.

  - by adlanelm

  Got a Win7 box with VS2010 Premium installed on it. Building desktop apps works just fine. But we got this solution with 15 SL4 and 21 desktop projects... Building the SL part of it takes too long. This is very irritating and encourages to drop TDD since every time I run a test it takes ~3 seconds for msbuild to find out that nothing changed and the project should be skipped. The projects are very small and there's nothing fancy in them and we hadn't any problems before we switched from VS2008+SL3. I've heard people complaining abound VS2010 speed in general, but nothing about SL4 build time. Is anyone experiencing same problems and is there any workaround for this?

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