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• How can I cluster short messages [Tweets] based on topic ? [Topic Based Clustering]

  - by Jagira

  Hello, I am planning an application which will make clusters of short messages/tweets based on topics. The number of topics will be limited like Sports [ NBA, NFL, Cricket, Soccer ], Entertainment [ movies, music ] and so on... I can think of two approaches to this Ask for users to tag questions like Stackoverflow does. Users can select tags from a predefined list of tags. Then on server side I will cluster them on based of tags. Pros:- Simple design. Less complexity in code. Cons:- Choices for users will be restricted. Clusters will not be dynamic. If a new event occurs, the predefined tags will miss it. Take the message, delete the stopwords [ predefined in a dictionary ] and apply some clustering algorithm to make a cluster and depending on its popularity, display the cluster. The cluster will be maintained according to its sustained popularity. New messages will be skimmed and assigned to corresponding clusters. Pros:- Dynamic clustering based on the popularity of the event/accident. Cons:- Increased complexity. More server resources required. I would like to know whether there are any other approaches to this problem. Or are there any ways of improving the above mentioned methods? Also suggest some good clustering algorithms.I think "K-Nearest Clustering" algorithm is apt for this situation.

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• Getting started with workflows in sharepoint 2010

  - by Thomas Stock

  Hi, I'm a beginning sharepoint developer asked to implement the following scenario in sharepoint 2010. We're a bit lost on the best approach to get started.. I'm really struggling to find the best practise solution. This is the flow: A user can make a request with a title and a description. A mail gets sent to the representative with a link to a form. A representative can approve or reject the request. If approved: A mail gets sent to Board with a link to form If rejected: A mail gets sent to the user with the message that it has been rejected. when the request was approved by the representative, the board can approve or reject the request. A mail gets sent to the user and the representative with the descision of the board. So the list has the following fields: Request title Request description Representative approval Representative description Board approval Board description The user should see the following form: Request title (editable) Request description (editable) The representative should see the following form: Request title (read-only) Request description (read-only) Representative approval (editable) Representative description (editable) The Board should see the following form: Request title (read-only) Request description (read-only) Representative approval (read-only) Representative description (read-only) Board approval (editable) Board description (editable) My questions: What tool is most appropriate for making the forms? Infopath? SPD? VS2010? How do I handle rights to make sure only the board can access the board edit form? What kind of workflow do I use? When do I start the workflow(s)? What do I use to develop the workflow(s)? How do I handle rights when showing the listview with all requests? How can I build the links in the mails sent to the different groups. Thanks in advance for any advice.

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• ASP.NET MVC: Can't figure out what VirtualPath is?

  - by Ryan_Pitts

  I have a View that displays a list of images and i am now trying to get it to display the images as thumbnails. Well, i'm pretty sure i got most of it right using VirtualPath's from a custom ActionResult although i can't seem to figure out what it is making the VirtualPath url?? BTW, i'm using XML to store the data from the images instead of SQL. Here is my code: Code from my custom ActionResult: public class ThumbnailResult : ActionResult { public ThumbnailResult(string virtualPath) { this.VirtualPath = virtualPath; } public string VirtualPath { get; set; } public override void ExecuteResult(ControllerContext context) { context.HttpContext.Response.ContentType = "image/bmp"; string fullFileName = context.HttpContext.Server.MapPath("~/Galleries/WhereConfusionMeetsConcrete/" + VirtualPath); using (System.Drawing.Image photoImg = System.Drawing.Image.FromFile(fullFileName)) { using (System.Drawing.Image thumbPhoto = photoImg.GetThumbnailImage(100, 100, null, new System.IntPtr())) { using (System.IO.MemoryStream ms = new System.IO.MemoryStream()) { thumbPhoto.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); context.HttpContext.Response.BinaryWrite(ms.ToArray()); context.HttpContext.Response.End(); } } } } } Code for my Controller: public ActionResult Thumbnail(string id) { return new ThumbnailResult(id); } Code for my View: <% foreach (var image in ViewData.Model) { %> <a href="../Galleries/TestGallery1/<%= image.Path %>"><img src="../Galleries/TestGallery1/thumbnail/<%= image.Path %>" alt="<%= image.Caption %>" /></a> <br /><br /><%= image.Caption %><br /><br /><br /> <% } %> Any help would be greatly appreciated!! Let me know of any questions you have as well. :) Thanks!

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• Getting all selected checkboxes values using ajax and jsp/servlets?

  - by A.S al-shammari

  Hi.. I'm developing a jsp/serlvet application. I have a page with a list of inputs as checkboxes . I want to send values of selected buttons to a servlet using ajax/jquery. In the servlet , I want to extract these values and use them . for example: The user checks some checkboxes , for example, list of messages. He/She presses Delete Link to delete selected messages. I searched and found something like this : $("#inboxDeleteSelected").click(function(){ var data = { 'checkBoxList[]' : []}; var list=$(":input:checkbox:checked"); // getting all selected checkboxes. $(list.each(function() { data['checkBoxList[]'].push($(this).val()); })); $.post("servlet?do=deleteSelected",data,function(d){ // do something here }); }); My questions: How can I send selected checkboxes values to a servlet ? How can I extract these values in the servlet ? Note: I don't use submit button to submit the selected checkboxes,Indeed I use link/anchor to send those values .

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• MVC3 DropDownListFor selected value does not reset if I set the Id

  - by BarryFanta

  I've read a lot of posts on here regarding the dropdown selected value issues (not showing etc etc...) but mine is the opposite problem. I want the drop down to always reset after the view is returned after a button submits the page through the controller action. So how I've structured it all works but is it possible to reset the dropdown list each time? I can't find a way to do it and I've tried a lot of ways, believe me. My View: @Model.PspSourceModel.PayAccount.PaymentProviderId <br /> @Html.DropDownListFor( x => x.PspSourceModel.PayAccount.PaymentProviderId, new SelectList(Model.PspSourceModel.PaymentProviders, "Value", "Text", "-- please select --"), "-- please select --" My Controller: // I've tried forcing the selected value id here - doesn't effect the dropdownlist still? pspVM.PspSourceModel.PayAccount.PaymentProviderId = 1; return (View(pspVM)); My Webpage shows: 1 (the id I set in the Action) dropdownlist with the id=6 or whatever value was chosen prior to submitting the form. From the questions and answers on SO and the wider web I thought the dropdownlist seems tied to the id you choose but how do I override that to reset the dropdown to 'please select' each time? Thanks in advance.

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• Address family not supported by protocol exception

  - by srg

  I'm trying to send a couple of values from an android application to a web service which I've setup. I'm using Http Post to send them but when I run the application I get the error- request time failed java.net.SocketException: Address family not supported by protocol. I get this while debugging with both the emulator as well as a device connected by wifi. I've already added the internet permission using: <uses-permission android:name="android.permission.INTERNET" /> This is the code i'm using to send the values void insertData(String name, String number) throws Exception { String url = "http://192.168.0.12:8000/testapp/default/call/run/insertdbdata/"; HttpClient client = new DefaultHttpClient(); HttpPost post = new HttpPost(url); try { List<NameValuePair> params = new ArrayList<NameValuePair>(2); params.add(new BasicNameValuePair("a", name)); params.add(new BasicNameValuePair("b", number)); post.setEntity(new UrlEncodedFormEntity(params)); HttpResponse response = client.execute(post); }catch(Exception e){ e.printStackTrace(); } Also I know that my web service work fine because when I send the values from an html page it works fine - <form name="form1" action="http://192.168.0.12:8000/testapp/default/call/run/insertdbdata/" method="post"> <input type="text" name="a"/> <input type="text" name="b"/> <input type="submit"/> I've seen questions of similar problems but haven't really found a solution. Thanks

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• Insert Stored Procedure does not Create Database Record

  - by SidC

  Hello All, I have the following stored procedure: ALTER PROCEDURE Pro_members_Insert @id int outPut, @LoginName nvarchar(50), @Password nvarchar(15), @FirstName nvarchar(100), @LastName nvarchar(100), @signupDate smalldatetime, @Company nvarchar(100), @Phone nvarchar(50), @Email nvarchar(150), @Address nvarchar(255), @PostalCode nvarchar(10), @State_Province nvarchar(100), @City nvarchar(50), @countryCode nvarchar(4), @active bit, @activationCode nvarchar(50) AS declare @usName as varchar(50) set @usName='' select @usName=isnull(LoginName,'') from members where LoginName=@LoginName if @usName <> '' begin set @ID=-3 RAISERROR('User Already exist.', 16, 1) return end set @usName='' select @usName=isnull(email,'') from members where Email=@Email if @usName <> '' begin set @ID=-4 RAISERROR('Email Already exist.', 16, 1) return end declare @MemID as int select @memID=isnull(max(ID),0)+1 from members INSERT INTO members ( id, LoginName, Password, FirstName, LastName, signupDate, Company, Phone, Email, Address, PostalCode, State_Province, City, countryCode, active,activationCode) VALUES ( @Memid, @LoginName, @Password, @FirstName, @LastName, @signupDate, @Company, @Phone, @Email, @Address, @PostalCode, @State_Province, @City, @countryCode, @active,@activationCode) if @@error <> 0 set @ID=-1 else set @id=@memID Note that I've "inherited" this sproc and the database. I am trying to insert a new record from my signup.aspx page. My SQLDataSource is as follows: <asp:SqlDataSource runat="server" ID="dsAddMember" ConnectionString="rmsdbuser" InsertCommandType="StoredProcedure" InsertCommand="Pro_members_Insert" ProviderName="System.Data.SqlClient"> The click handler for btnSave is as follows: Protected Sub btnSave_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSave.Click Try dsAddMember.DataBind() Catch ex As Exception End Try End Sub When I run this page, signup.aspx, provide required fields and click submit, the page simply reloads and the database table does not reflect the newly-inserted record. Questions: 1. How do I catch the error messages that might be returned from the sproc? 2. Please advise how to change signup.aspx so that the insert occurs. Thanks, Sid

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• jQuery arrays - newbie needs a kick start

  - by Jonny Wood

  I've only really started using this site and alredy I am very impressed by the community here! This is my third question in less than three days. Hopefully I'll be able to start answering questions soon instead of just asking them! I'm fairly new to jQuery and can't find a decent tutorial on Arrays. I'd like to be able to create an array that targets several ID's on my page and performs the same effect for each. For example I have tabs set up with the following: $('.tabs div.tab').hide(); $('.tabs div:first').show(); $('.tabs ul li:first a').addClass('current'); $('.tabs ul li a').click(function(){ $('.tabs ul li a').removeClass('current'); $(this).addClass('current'); var currentTab = $(this).attr('href'); $('.tabs div.tab').hide(); $(currentTab).show(); return false; }); I've used the class .tag to target the tabs as there are several sets on the same page, but I've heard jQuery works much faster when targetting ID's How would I add an array to the above code to target 4 different ID's? I've looked at var myArray = new Array('#id1', 'id2', 'id3', 'id4'); And also var myValues = [ '#id1', 'id2', 'id3', 'id4' ]; Which is correct and how do I then use the array in the code for my tabs...?

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• How is external memory, internal memory, and cache organized?

  - by goldenmean

  Consider a system as follows:= A hardware board having say ARM Cortex-A8 and Neon Vector coprocessor, and Embedded Linux OS running on Cortex-A8. On this environment, if there is some application - say, a video decoder is executing - then: How is it decided that which buffers would be in external memory, which ones would be allocated in internal SRAM, etc. When one says calloc/malloc on such system/code, the pointer returned is from which memory: internal or external? Can a user make buffers to be allocated to the memories of his choice (internal/external)? In ARM architectures, there is another memory called as Tightly coupled memory (TCM). What is that and how can user enable and use it? Can I declare buffers in this memory? Do I need to see the memory map (if any) of the hardware board to understand about all these different physical memories present in a typical hardware board? How much of a role does the OS play in distinguishing these different memories? Sorry for multiple questions, but i think they all are interlinked.

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• Are there any code critique sites or similar resources?

  - by Ukko

  I have noticed when people post example code illustrating some issue that they are having often they will gather a number of comments addressing the quality of the code they presented and not the actual problem asked. This is very helpful--if not well directed. Often, this is wasted effort since the asker is often not receptive and the code is often chopped down to something small to post leaving lots of rough edges. In the old days you would see people asking questions like this on comp.lang.lisp and other parts of the comp.lang hierarchy. But that bit of the net kind of sank into the sewers of neglect. Is there a comparable one-stop-shop today? I am partially asking for selfish reasons, I know how to write good idiomatic C, Lisp, O'Caml, and Java code. But I learned C++ pre-template and STL, those rusty skills are not really applicable to today's C++. I have picked up languages like Scala in a vacuum and get by, but am I really doing it correctly? There are so many ways you can abuse a language, I am currently working against a codebase of Fortran written in C, and I recognize and loathe the "that guy" who wrote it. I don't want to be someone else's "that guy" if I can help it. Just because it works does not mean that one did not totally miss the boat on how it should have been done. Do you seek out this type of critique? If so how, where and why? What types of benefits do you derive from it? How about abuse and trolls?

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• What is the procedure for debugging a production-only error?

  - by Lord Torgamus

  Let me say upfront that I'm so ignorant on this topic that I don't even know whether this question has objective answers or not. If it ends up being "not," I'll delete or vote to close the post. Here's the scenario: I just wrote a little web service. It works on my machine. It works on my team lead's machine. It works, as far as I can tell, on every machine except for the production server. The exception that the production server spits out upon failure originates from a third-party JAR file, and is skimpy on information. I search the web for hours, but don't come up with anything useful. So what's the procedure for tracking down an issue that occurs only on production machines? Is there a standard methodology, or perhaps category/family of tools, for this? The error that inspired this question has already been fixed, but that was due more to good fortune than a solid approach to debugging. I'm asking this question for future reference. Some related questions: Test accounts and products in a production system Running test on Production Code/Server

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• php request variables assigning $_GEt

  - by chris

  if you take a look at a previous question http://stackoverflow.com/questions/2690742/mod-rewrite-title-slugs-and-htaccess I am using the solution that Col. Shrapnel proposed- but when i assign values to $_GET in the actual file and not from a request the code doesnt work. It defaults away from the file as if the $_GET variables are not set The code I have come up with is- if(!empty($_GET['cat'])){ $_GET['target'] = "category"; if(isset($_GET['page'])){ $_GET['pageID'] = $_GET['page']; } $URL_query = "SELECT category_id FROM cats WHERE slug = '".$_GET['cat']."';"; $URL_result = mysql_query($URL_query); $URL_array = mysql_fetch_array($URL_result); $_GET['category_id'] = $URL_array['category_id']; }elseif($_GET['product']){ $_GET['target'] = "product"; $URL_query = "SELECT product_id FROM products WHERE slug = '".$_GET['product']."';"; $URL_result = mysql_query($URL_query); $URL_array = mysql_fetch_array($URL_result); print_r($URL_array); $_GET['product_id'] = $URL_array['product_id']; The original variable string that im trying to represent is /cart.php?Target=product&product_id=16142&category_id=249 And i'm trying to build the query string variables with code and including cart.php so i can use cleaner URL's So I have product/product-title-with-clean-url/ going to slug.php?product=slug Then the slug searches the db for a record with the matching slug and returns the product_id as in the code above.Then built the query string and include cart.php

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• MEF Import Composition Issues

  - by Tim

  I've read all the questions I can find regarding the issues of composing imports without exporting the containing class but I can't find a solution to my problem. Does anybody know a way to achieve what I'm trying to do? My module assemblies have forms and classes which they use internally. These forms need access to some of the exported contracts but imports are not loaded as they are not in the MEF 'composition tree' Host assembly: public class Host { public Host() { /* Compose parts here... */ } [Export(typeof(Licence))] public Licence LoadedLicence { get; set; } [Export(typeof(IModule))] public List<IModule> LoadedModules { get; set; } } Module assembly: [Export(typeof(IModule))] public class Module : IModule { public Module() { } public void DoSomething() { SubForm sub = new SubForm(); sub.ShowDialog(); } [Import(typeof(Licence))] public Licence LoadedLicence { get; set; } // This works here } public class SubForm : Form { public SubForm () { } [Import(typeof(Licence))] public Licence LoadedLicence { get; set; } // This doesn't work in here } As far as I can see, my options are: Pass parameters to constructors (pain) Use a dummy export on the classes that need imports satisfying? Any others?

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• maximum memory which malloc can allocate!

  - by Vikas

  I was trying to figure out how much memory I can malloc to maximum extent on my machine (1 Gb RAM 160 Gb HD Windows platform). I read that maximum memory malloc can allocate is limited to physical memory.(on heap) Also when a program exceeds consumption of memory to a certain level, the computer stops working because other applications do not get enough memory that they require. So to confirm,I wrote a small program in C, int main(){ int *p; while(1){ p=(int *)malloc(4); if(!p)break; } } Hoping that there would be a time when memory allocation will fail and loop will be breaked. But my computer hanged as It was an infinite loop. I waited for about an hour and finally I had to forcely shut down my computer. Some questions: Does malloc allocate memory from HD also? What was the reason for above behaviour? Why didn't loop breaked at any point of time.? Why wasn't there any allocation failure?

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• help on developing enterprise level software solutions

  - by wefwgeweg

  there is a specific niche which I would like to target by providing a complete enterprise level software solution.... the problem is, where do i begin ? meaning, i come from writing just desktop software on VB/ASP .net/PHP/mysql and suddenly unfamiliar terms popup like Oracle, SAP Business Information Warehouse, J2EE.... obviously, something is pointing towards Java, is it common for software suites, or solutions to be developed 100% on Java technology and standards? Are there any other platform to build enterprise level software on ? i am still lacking understanding what exactly is "Enterprise level" ? what is sufficient condition to call a software that sells for $199 and then suddenly it's $19,999 for "enterprise" package. I dont understand why there is such a huge discrepancy between "standard" and "enterprise" versions of software. Is it just attempting to bag large corporations on a spending spree ? so why does one choose to develop so called "enterprise" softwares ? is it because of the large inflated price tag you can justify with ? i would also like some more enterpreneural resources on starting your own enterprise software company in a niche.... Thank you for reading, i am still trying to find the right questions.

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• Why won't WPF databindings show text when ToString() has a collaborating object?

  - by Jay

  In a simple form, I bind to a number of different objects -- some go in listboxes; some in textblocks. A couple of these objects have collaborating objects upon which the ToString() method calls when doing its work -- typically a formatter of some kind. When I step through the code I see that when the databinding is being set up, ToString() is called the collaborating object is not null and returns the expected result when inspected in the debugger, the objects return the expected result from ToString() BUT the text does not show up in the form. The only common thread I see is that these use a collaborating object, whereas the other bindings that show up as expected simply work from properties and methods of the containing object. If this is confusing, here is the gist in code: public class ThisThingWorks { private SomeObject some_object; public ThisThingWorks(SomeObject s) { some_object = s; } public override string ToString() { return some_object.name; } } public class ThisDoesntWork { private Formatter formatter; private SomeObject some_object; public ThisDoesntWork(SomeObject o, Formatter f) { formatter = f; some_object = o; } public override string ToString() { return formatter.Format(some_object.name); } } Again, let me reiterate -- the ToString() method works in every other context -- but when I bind to the object in WPF and expect it to display the result of ToString(), I get nothing. Update: The issue seems to be what I see as a buggy behaviour in the TextBlock binding. If I bind the Text property to a property of the DataContext that is declared as an interface type, ToString() is never called. If I change the property declaration to an implementation of the interface, it works as expected. Other controls, like Label work fine when binding the Content property to a DataContext property declared as either the implementation or the interface. Because this is so far removed from the title and content of this question, I've created a new question here: http://stackoverflow.com/questions/2917878/why-doesnt-textblock-databinding-call-tostring-on-a-property-whose-compile-tim

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• Timer appears to be pausing when screen becomes inactive

  - by elchuppa

  So I have a very simple android activity that starts a timer when you hit a button. Timer timer = new Timer(); timer.schedule(new TimerTask() { @Override public void run() { doStuff(); } }, 15 * 60 * 1000); So this worked reasonably well for me when I was testing but as it turns out when the screen becomes inactive so does the timer. I was a bit surprised by this. I understand you need to create a service to have anything running in the background but I hadn't realized this is required for an activity in the foreground when the phone has inactivated the screen due to lack of activity. What confuses me is I think this worked as I expected originally and just in the last few weeks or so has the timer been affected by the phone saving power. I could be wrong though.. So basically my questions are: am I seeing expected behavior? Do I need to create all timers as services or somehow disallow powersaving? thanks for any advice, Patrick

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• What is the difference between Inversion of Control and Dependency injection in C++?

  - by rlbond

  I've been reading recently about DI and IoC in C++. I am a little confused (even after reading related questions here on SO) and was hoping for some clarification. It seems to me that being familiar with the STL and Boost leads to use of dependency injection quite a bit. For example, let's say I made a function that found the mean of a range of numbers: template <typename Iter> double mean(Iter first, Iter last) { double sum = 0; size_t number = 0; while (first != last) { sum += *(first++); ++number; } return sum/number; }; Is this dependency injection? Inversion of control? Neither? Let's look at another example. We have a class: class Dice { public: typedef boost::mt19937 Engine; Dice(int num_dice, Engine& rng) : n_(num_dice), eng_(rng) {} int roll() { int sum = 0; for (int i = 0; i < num_dice; ++i) sum += boost::uniform_int<>(1,6)(eng_); return sum; } private: Engine& eng_; int n_; }; This seems like dependency injection. But is it inversion of control? Also, if I'm missing something, can someone help me out?

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• ios UITableView reloadData don't increase content height

  - by Zoltan Varadi

  I'm facing a strange error in my iOS app and haven't been able to figure out the reason why. In my UITableView i can add new cells, so i refresh the array that is the datasource and call reloadData. Everything works without error. The numberOfRowsInSection is called again, and it's value is one more than it's previous value was. The new cell even gets inserted at the bottom of the tableview, but i cant scroll down to it. I only know that it's there because the tableview bounces and i can see it. I'm guessing the tableview's content height is not getting increased for some reason, but i have no idea why. I'm using iOS 6 btw. Any help is very much appreciated! Thanks, Zoli EDIT, answers for Srikanth's questions: How is data getting added. There's an NSArray containing objects of a specific type. The array.count is the number of the number of cells. This NSArray gets its values from a database query. When you say, you are refreshing the array, what do you mean. By refreshing the array i mean i execute a new query in the database and put the results of this query into an NSArray. this will be the tableview's datasource array. Like this: dataSourceArray = [dbManager executeQuery]; [tableView reloadData]; Are you adding the data within the same view controller Yes. Can you show some code as to what you are doing See above. Is the table view at the root of the view controllers view or is it within another view The tableview is the main view's first child. Can you try adding data to the array at the beginning, so that you can view the cell being added at the top. I don't understand what you mean.

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• PHP: json_decode dumping NULL, BOM not found

  - by SerEnder

  I've been trying to find out why this 'json_encode'd string isn't parsing out correctly, and came across previously answered questions that had the UTF BOM sequence that was throwing the error, but didn't help me here. Here's the code that isn't currently working: //Decode the notes attached to the sig $aNotes = json_decode($rule->getNotes(),true); $bom = pack("CCC",0xef,0xbb,0xbf); if(0 == strncmp($rule->getNotes(),$bom,3)) { print('BOM detected - json encoding in UTF-8<br/>'); } else { print('BOM NOT detected - json encoding correctly<br/>'); } print('rule->getNotes:<br/>' . $rule->getNotes() .'<br/>'); var_dump($aNotes); Which generates this result: BOM NOT detected - json encoding correctly rule->getNotes: [{"lDate":"Unknown","sAuthor":"Unknown","sNote":"This is a general purpose Russian spam rule that matches anything starting with 2, 3 or 4 hex digits followed by a domain name ending with .ru -RSK 2010-05-10"},{"lDate":"1295031463082","sAuthor":"Drew Thorstenson","sNote":"this is Ryan's ru rule"}] NULL I've run it through JSON Lint, which said it was valid, and An Online JSON Parser which parsed it correctly too. Any insight would be greatly appreciated.

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• Whose fault is a NullReferenceException?

  - by stefan.at.wpf

  I'm currently working on a class which exposes an internal List through a property. The List shall and can be modified. The problem is, entries in the internal list could be set to null from outside the class. My code actually looks like this: class ClassWithList { List<object> _list = new List<object>(); // get accessor, which however returns the reference to the list, // therefore the list can be modified (this is intended) public List<object> Data { get { return _list; } } private void doSomeWorkWithTheList() { foreach(object obj in _list) // do some work with the objects in the list without checking for null. } } So now in the doSomeWorkWithTheList() I could always check whether the current list entry is null or I could just asume that the person using this class doesn't have the great idea to set entries to null. So finally the questions end up in: Whose fault is a NullReferenceException in this case? Is it the fault of the class developer not checking everything for null (which would make code generally - not only in this class - more complex) or is it the fault of the user of this class, as setting a List entry to null doesn't really make sense? I'd tend to generally not check values for null except in some really special cases. Is this a bad style or de facto standard / standard in praxis? I know there's probably no ultimate answer for this, I'm just missing enough experience for such thing and therefore wondering what other developers think about such cases and want to hear what's done in reality about checking null (or not).

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• gl_FragColor and glReadPixels

  - by chun0216

  I am still trying to read pixels from fragment shader and I have some questions. I know that gl_FragColor returns with vec4 meaning RGBA, 4 channels. After that, I am using glReadPixels to read FBO and write it in data GLubyte *pixels = new GLubyte[640*480*4]; glReadPixels(0, 0, 640,480, GL_RGBA, GL_UNSIGNED_BYTE, pixels); This works fine but it really has speed issue. Instead of this, I want to just read RGB so ignore alpha channels. I tried: GLubyte *pixels = new GLubyte[640*480*3]; glReadPixels(0, 0, 640,480, GL_RGB, GL_UNSIGNED_BYTE, pixels); instead and this didn't work though. I guess it's because gl_FragColor returns 4 channels and maybe I should do something before this? Actually, since my returned image (gl_FragColor) is grayscale, I did something like float gray = 0.5 //or some other values gl_FragColor = vec4(gray,gray,gray,1.0); So is there any efficient way to use glReadPixels instead of using the first 4 channels method? Any suggestion? By the way, this is on opengl es 2.0 code.

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• Finding the width of a directed acyclic graph... with only the ability to find parents

  - by Platinum Azure

  Hi guys, I'm trying to find the width of a directed acyclic graph... as represented by an arbitrarily ordered list of nodes, without even an adjacency list. The graph/list is for a parallel GNU Make-like workflow manager that uses files as its criteria for execution order. Each node has a list of source files and target files. We have a hash table in place so that, given a file name, the node which produces it can be determined. In this way, we can figure out a node's parents by examining the nodes which generate each of its source files using this table. That is the ONLY ability I have at this point, without changing the code severely. The code has been in public use for a while, and the last thing we want to do is to change the structure significantly and have a bad release. And no, we don't have time to test rigorously (I am in an academic environment). Ideally we're hoping we can do this without doing anything more dangerous than adding fields to the node. I'll be posting a community-wiki answer outlining my current approach and its flaws. If anyone wants to edit that, or use it as a starting point, feel free. If there's anything I can do to clarify things, I can answer questions or post code if needed. Thanks! EDIT: For anyone who cares, this will be in C. Yes, I know my pseudocode is in some horribly botched Python look-alike. I'm sort of hoping the language doesn't really matter.

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• How to select LI exept first and second ?

  - by Wazdesign

  Here is the structure of the content , I want to select all LI except the first two ( ie no-link) jQuery(document).ready(function(){ var nosubnav = jQuery('.first-level li:not(:has(ul))'); var nosubnavsize = jQuery('.first-level li:not(:has(ul))').size(); jQuery(nosubnav).css('border' , '1px solid red'); alert('List item which does not have submenu '+nosubnavsize); }); div class="navigation-container"> <ul class="first-level"> <li><a href="#">No Link</a></li> <li><a href="#">No Link</a></li> <li><a href="#">Link 1</a></li> <li><a href="#">Link 2</a> <ul> <li><a href="#">Link2.1</a></li> <li><a href="#">Link2.2</a> <ul> <li><a href="#">Link 2.2.1</a></li> </ul> </li> </ul> </li> <li><a href="#">Link </a></li> </ul> </div> related Question : http://stackoverflow.com/questions/2771801/how-to-count-li-which-does-not-have-ul

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• DB Design to store custom fields for a table

  - by Fazal

  Hi All, this question came up based on the responses I got for the question http://stackoverflow.com/questions/2785033/getting-wierd-issue-with-to-number-function-in-oracle As everyone suggested that storing Numeric values in VARCHAR2 columns is not a good practice (which I totally agree with), I am wondering about a basic Design choice our team has made and whether there are better way to design. Problem Statement : We Have many tables where we want to give certain number of custom fields. The number of required custom fields is known, but what kind of attribute is mapped to the column is available to the user E.g. I am putting down a hypothetical scenario below Say you have a laptop which stores 50 attribute values for every laptop record. Each laptop attributes are created by the some admin who creates the laptop. A user created a laptop product lets say lap1 with attributes String, String, numeric, numeric, String Second user created laptop lap2 with attributes String,numeric,String,String,numeric Currently there data in our design gets persisted as following Laptop Table Id Name field1 field2 field3 field4 field5 1 lap1 lappy lappy 12 13 lappy 2 lap2 lappy2 13 lappy2 lapp2 12 This example kind of simulates our requirement and our design Now here if somebody is lookinup records for lap2 table doing a comparison on field2, We need to apply TO_NUMBER. select * from laptop where name='lap2' and TO_NUMBER(field2) < 15 TO_NUMBER fails in some cases when query plan decides to first apply to_number instead of the other filter. QUESTION Is this a valid design? What are the other alternative ways to solve this problem One of our team mates suggested creating tables on the fly for such cases. Is that a good idea How do popular ORM tools give custom fields or flex fields handling? I hope I was able to make sense in the question. Sorry for such a long text.. This causes us to use TO_NUMBER when queryio

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