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• Please recommend good books for telemetry / SCADA system design & programming

  - by Mawg

  I am looking at several projects, all with roughly the same fucntionality. Some instruments collect some data (or control some functionality). They commmunicate by Internet (Etehrnet/wifi/GPRS/sasatellite) with a databse server which stores the measurements and provides a browser based means of qeurying the data, prodcuing reports, etc (and possibly also allows control of the remote equipment). Can anyone recommend a good book describing an approach to developing such a software architecture, keeping it generic, which tools, languages. test methods, etc to use? (note to self: ask a similar question about possible existing frameworks)

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• c# Generic overloaded method dispatching ambiguous

  - by sebgod

  Hello, I just hit a situation where a method dispatch was ambiguous and wondered if anyone could explain on what basis the compiler (.NET 4.0.30319) chooses what overload to call interface IfaceA { } interface IfaceB<T> { void Add(IfaceA a); T Add(T t); } class ConcreteA : IfaceA { } class abstract BaseClassB<T> : IfaceB<T> { public virtual T Add(T t) { ... } public virtual void Add(IfaceA a) { ... } } class ConcreteB : BaseClassB<IfaceA> { // does not override one of the relevant methods } void code() { var concreteB = new ConcreteB(); // it will call void Add(IfaceA a) concreteB.Add(new ConcreteA()); } In any case, why does the compiler not warn me or even why does it compile? Thank you very much for any answers.

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• System.Windows.Forms.DataGridView does not display data

  - by Water Cooler v2

  All I am doing is a simple: // Both the methods, order.GetAllOrderItems() and order.GetOrderedItemsWhereBrandIs("foo") // return an IEnumerable<T> so the assignment to the DataSource property of the DataGridView // should be fine. The problem is in re-assigning the data source property. public void DisplayItems() { // The data appears if I have just this line. dgvOrderedItems.DataSource = order.GetAllOrderItems(); dgvOrderedItems.DataSource = null; // This time the data grid does not take the new data source. Instead, because // of the null assignment in the previous statement, it displays no data at all. dgvOrderedItems.DataSource = order.GetOrderedItemsWhereBrandIs("Lenovo"); } My question is: is there a way to change the data source of a DataGridView control once it has been set? I am using C# 4.0 and Visual Studio 2010 for development.

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• ASP.Net Web API Routing fails when api is created as a web application under another asp.net site in IIS

  - by neo

  I developed a rest api using ASP.net web api. When I deploy this rest api on iis, I need to create it as a web application under an asp.net web site. When I was deploying the rest api as a new web site in iis, then things worked fine. I was using the following Route api/{controller}/{id}. When I created the rest api as a web application underneath asp.net web site project, I named the web application as api. I can't access the api methods now. Can someone point what I do wrong?

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• How can I selectively override a django .count() method

  - by Tom Viner

  I'm using postGresSQL and my main table has about 20,000 rows. Sometimes count() methods can take ages or even timeout. Mod.manager.filter(...).count() I need to selectively override the count() method depending on what filter has been applied. Just having a cache of results would be a great gain but I'd like to be able to say: if filter query is just {'enabled'=True} then return 20,000 without touching the db. Note: I can't prevent the call to .count() as it's inside django's pagination, which always does a count.

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• Java: how to have global values inside a class?

  - by HH

  I want less methods. I want a common global TestClass from which I could use any of its value inside the class. import java.util.*; import java.io.*; public class TestClass { TestClass(String hello){ String hallo = hello; String halloSecond = "Saluto!"; } public static void main(String[] args) { TestClass test = new TestClass("Tjena!"); System.out.println("I want "Tjena!": " + test.hallo); TestClass testSecond = new TestClass("1"); System.out.println("I want Saluto!:" + test.halloSecond); System.out.println("I want Saluto!:" + testSecond.halloSecond); // How can I get glob.vars like the "Saluto!"? } }

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• What alternatives are there for asp.net forms authentication?

  - by Eytan Levit

  Hi, We are developing a web app that will have a pretty complex user and permission system. The general idea is that we have 3 levels of security: a simple user - that can only access basic data that is in a data repository a manager - that can open up data repositories a superuser - that can open up repository factories. each repository contains various data types(text, images, etc etc). We are looking for authentication methods that will allow us: 1. Scalability. 2. Customization. 3. To create permissions that will effect the GUI + deny access to certain pages. 4. To create predefined roles - that will allow for easy setup of new users. 5. To create custom roles for specific users - allowing them permission sets that are different from the predefined roles. Thanks in advance

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• OpenLayers: Get resolution of map in a given projection (4326)

  - by David Pfeffer

  I'm using OpenLayers to display OpenStreetMap maps. (Though, I'd assume this should be general enough to work for any map product...) I'm displaying some very sophisticated vector overlays, and the amount and resolution of the features I'm returning from the server via GeoJSON to overlay has proven too much for many computers. What I'd like to do now instead is to only send data befitting the resolution of the current zoom. This should be relatively easy to do using the getResolution and calculateBounds methods on the Map object. calculateBounds returns a Bounds object that then can be transformed between the map projection and display projection. How do I transform the resolution into my desired projection (4326 in this case)?

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• Embed Icons into WPF Application as Resource

  - by rattrick1

  I am trying to embed an icon into my my WPF application so that I can pull it out for use as an icon in the Window 7 JumpList using the following code: newScene.IconResourcePath = System.Reflection.Assembly.GetEntryAssembly().Location; newScene.IconResourceIndex = 0; I've gotten it to work using the following method: http://dennisdel.com/?p=38 However, it doesn't seem like the best approach and it seems like there should be an easier way to embed an icon resource into my application while still leaving the "Icon and Manifest" option checked in the Application properties for my program. I've tried numerous methods including setting the icon build action as a resource and an embedded resource, but every time I open my .exe in a resource editor, the icon does not appear. Any suggestions?

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• What should I do that GWT use <th> instead of <td>?

  - by Paulus

  To build a HTML table I use direct DOM instead of a predefined Widget to set thead and tbody. But when I insert a cell with the insertCell() method GWT inserts an td element but should insert an th element. So TableElement table = Document.get().createTableElement(); TableSectionElement thead = table.createTHead(); TableRowElement headRow = thead.insertRow(-1); headRow.insertCell(-1).setInnerText( "header1" ); gives table/thead/tr/td but should give table/thead/tr/th Any idea how to solve this problem? Use the "old-school" DOM.createXXX()-Methods?

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• CodeIgniter Validation in Library does not accept callback.

  - by Lukas Oppermann

  Hey guys, my problem is the following: I am writing a login library. This library has a function _validation() and this uses the validation library to validate the data. With using normal validation methods it works just fine, but using a callback function just does not work. It is not called. I call it like this. $this->CI->form_validation->set_rules('user', 'Username', 'required|callback__check_user'); The functions name is _check_user and it uses the username _check_user($user). The function itself works fine and I can also call it in the class ($this-_check_user('username')) with a working result. I am guessing, there might be a problem because I am not workin in a controller so I have a CI instance $this-CI instead of just the original instance $this- Does anyone have a clue how to fix this? Thanks in advance.

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• Which langauge should i use for Artificail intelligence on web projects

  - by Mirage

  I have to do one project for my thesis involving Artificail intelligence , collaborative filtering and machine learning methods. I only know PHP/mysq/JS and there is not much AI stuff examples in PHP. There are some books on AI on internet but they use Java , Python. Now i have to apply AI techniques on web application. WHich language should i choose java or python. I searhed on internet that i can call java classes inside my php so that can help as as i am very good at php i have also seen that python can also be used with php as well So which way should i go and roughly how much it will take me to learn java i have done java basics but that was 6 years ago

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• Coldfusion CFC creation taking a variable amout of time to execute.

  - by Bazza

  I've been doing some logging of object creation times in our open account process in production. Periodically, initializing an object would take way longer than expected. By initializing I mean calling it's init() and passing a couple of arguments that may be simple variables or objects. e.g. <cfset validateObj = createObject("component", "compExample").init( productionMode = VARIABLES.productionMode, ipWhiteListed = isWhiteListed, ipLocatorObj = VARIABLES.ipLocatorObj ) /> Thats all that happens in init() methods. Generally the execution time would be 0ms, but at random times I might get 3 or 3.5 seconds. This is not specific to one particular server or to our generally busy period. It appears to be quite random. One thought was that these templates were being evicted from our template cache as they are not especially frequently used, although I checked cfstat on a number of servers and the max CP/Sec is -1. Running CF 8,0,1 Has anybody else ever come across this?

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• Does lamda in List.ForEach leads to memory leaks and performance problems ?

  - by Monomachus

  I have a problem which I could solve using something like this sortedElements.ForEach((XElement el) => PrintXElementName(el,i++)); And this means that I have in ForEach a lambda which permits using parameters like int i. I like that way of doing it, but i read somewhere that anonymous methods and delegates with lambda leads to a lot of memory leaks because each time when lambda is executed something is instantiated but is not released. Something like that. Could you please tell me if this is true in this situation and if it is why?

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• Why is run() not immediately called when start() called on a thread object in java

  - by pi

  Or is it? I have a thread object from: Thread myThread = new Thread(pObject); Where pObject is an object of a class implementing the Runnable interface and then I have the start method called on the thread object like so: myThread.start(); Now, my understanding is that when start() is called, the JVM implicitly (and immediately) calls the run() method which may be overridden (as it is in my case) However, in my case, it appears that the start() method is not called immediately (as desired) but until the other statements/methods are completed from the calling block i.e. if I had a method after the start() call like so: myThread.start(); doSomethingElse(); doSomthingElse() gets executed before the run() method is run at all. Perhaps I am wrong with the initial premise that run() is always called right after the start() is called. Please help! The desired again is making executing run() right after start(). Thanks.

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• why primitive type will call first rather than wrapper classes?

  - by kandarp

  Hello EveryOne, public class A { public void test(Integer i) { System.out.println("In Wrapper Method"); } public void test(int i) { System.out.println("In primitive Method"); } public static void main(String args[]) { A a = new A(); a.test(5); } } When I will call test method from main and pass integer argument, then it will call the method which accept primitive type as argument. I just want to know that why it call primitive type method rather than the method who accepts wrapper class as argument? Is there any rule, which java follow to call methods? Thanks,

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• ASP .NET MVC Secure all resources

  - by Tim

  How to enable Authentication on whole controller and disable only for certain action methods. I want authentication for all resources. If I write something like that: [Authorize] public class HomeController : BaseController { //This is public [UnAuthorized] public ActionResult Index() { ViewData["Message"] = "Welcome to ASP.NET MVC!"; return View(); } //This is private resource public ActionResult PrivateResource() { return View(); } } Then anyone can access this resource. Do you have any ideas how to make it better way?

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• Are there any tools to optimize the number of consumer and producer threads on a JMS queue?

  - by lindelof

  I'm working on an application that is distributed over two JBoss instances and that produces/consumes JMS messages on several JMS queues. When we configured the application we had to determine which threading model we would use, in particular the number of producing and consuming threads per queue. We have done this in a rather ad-hoc fashion but after reading the most recent columns by Herb Sutter in Dr Dobbs (in particular this one) I would like to size our threads in a more rigorous manner. Are there any methods/tools to measure the throughput of JMS queues (in particular JBoss Messaging queues) as a function of the number of producing/consuming threads?

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• Accessing wrapped method attribute in C#

  - by prostynick

  I have following code: public static void ProcessStep(Action action) { //do something here if (Attribute.IsDefined(action.Method, typeof(LogAttribute))) { //do something here [1] } action(); //do something here } For easy use I have some similar methods using method above. For example: public static void ProcessStep(Action<bool> action) { ProcessStep(() => action(true)); //this is only example, don't bother about hardcoded true } But when I use the second method (the one above), even if original action had attribute, code [1] will not be executed. How can I find if method is only wrapper and underlying method contains attribute and how to access this attribute?

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• In Vim, what is the best way to select, delete, or comment out large portions of multi-screen text?

  - by Edward Tanguay

  Selecting a large amount of text that extends over many screens in an IDE like Eclipse is fairly easy since you can use the mouse, but what is the best way to e.g. select and delete multiscreen blocks of text or write e.g. three large methods out to another file and then delete them for testing purposes in Vim when using it via putty/ssh where you cannot use the mouse? I can easily yank-to-the-end-of-line or yank-to-the-end-of-code-block but if the text extends over many screens, or has lots of blank lines in it, I feel like my hands are tied in Vim. Any solutions? And a related question: is there a way to somehow select 40 lines, and then comment them all out (with "#" or "//"), as is common in most IDEs?

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• Sharing a database connection with included classes in a Sinatra application

  - by imightbeinatree

  I'm converting a part of a rails application to its own sinatra application. It has some beefy work to do and rather than have a million helps in app.rb, I've separated some of it out into classes. Without access to rails I'm rewriting finder several methods and needing access to the database inside of my class. What's the best way to share a database connection between your application and a class? Or would you recommend pushing all database work into its own class and only having the connection established there? Here is what I have in in app.rb require 'lib/myclass' configure :production do MysqlDB = Sequel.connect('mysql://user:password@host:port/db_name') end I want to access it in lib/myclass.rb class Myclass def self.find_by_domain_and_stub(domain, stub) # want to do a query here end end I've tried several things but nothing that seems to work well enough to even include as an example.

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• A 'do' statement at the end of my perl script never runs

  - by Jeremy Petzold

  In my main script, I am doing some archive manipulation. Once I have completed that, I want to run a separate script to upload my archives to and FTP server. Separately, these scripts work well. I want to add the FTP script to the end of my archive script so I only need to worry about scheduling one script to run and I want to guarantee that the first script completes it work before the FTP script is called. After looking at all the different methods to call my FTP script, I settled on 'do', however, when my do statement is at the end of the script, it never runs. When I place it in my main foreach loop, it runs fine, but it runs multiple times which I want to avoid since the FTP script can handle having multiple archives to upload. Is there something I am missing? Why does it not run? Thanks

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• Java - How can I edit the size and position of a button using Swing?

  - by mino

  I have the following code but I'd like to structure several buttons of certain sizes. I'm just wondering how to do this as I've Googled it and found several different methods but none seem to work. Any advice? import javax.swing.*; public class GUI { public static void main(String[] args) { JFrame window = new JFrame(); window.setSize(500, 500); window.setTitle("My Application"); JButton button = new JButton("click me"); window.add(button); window.setVisible(true); } }

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• How to read and write UTF-8 to disk on the Android?

  - by Rob Kent

  I cannot read and write extended characters (French accented characters, for example) to a text file using the standard InputStreamReader methods shown in the Android API examples. When I read back the file using: InputStreamReader tmp = new InputStreamReader(in); BufferedReader reader = new BufferedReader(tmp); String str; while ((str = reader.readLine()) != null) { ... the string read is truncated at the extended characters instead of at the end-of-line. The second half of the string then comes on the next line. I'm assuming that I need to persist my data as UTF-8 but I cannot find any examples of that, and I'm new to Java. Can anyone provide me with an example or a link to relevant documentation?

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• Modular HTML in Adobe AIR? Is It Possible?

  - by Greg Bulmash

  When I write HTML with a PHP backend, I usually have a single header file and a single footer file with some PHP variables in them. The base skeleton for every page calls the header, contains the body content, and then calls the footer. That way, if I want to make changes to the header sitewide, I change one file. I'm working on developing the UI in my first Adobe AIR app and I'm wondering if there's some way to include such files in an HTML based page template there. Obviously, with the file read/write abilities in AIR, I can write a Javascript routine to pull data from a header file, parse it, and inject it into a placeholder. It just seems like such a kludge. I'm thinking there's gotta be some simple way to import a block of HTML into a page without an iFrame or complex post-processor. Something like a PHP include statement or perhaps the old Server Side Includes. Any methods you guys can recommend?

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