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  • How should I secure my webapp written using Wicket, Spring, and JPA?

    - by Martin
    So, I have an web-based application that is using the Wicket 1.4 framework, and it uses Spring beans, the Java Persistence API (JPA), and the OpenSessionInView pattern. I'm hoping to find a security model that is declarative, but doesn't require gobs of XML configuration -- I'd prefer annotations. Here are the options so far: Spring Security (guide) - looks complete, but every guide I find that combines it with Wicket still calls it Acegi Security, which makes me think it must be old. Wicket-Auth-Roles (guide 1 and guide 2) - Most guides recommend mixing this with Spring Security, and I love the declarative style of @Authorize("ROLE1","ROLE2",etc). I'm concerned about having to extend AuthenticatedWebApplication, since I'm already extending org.apache.wicket.protocol.http.WebApplication, and Spring is already proxying that behind org.apache.wicket.spring.SpringWebApplicationFactory. SWARM / WASP (guide) - This looks the newest (though the main contributor passed away years ago), but I hate all of the JAAS-styled text files that declare permissions for principals. I also don't like the idea of making an Action class for every single thing a user might want to do. Secure models also aren't immediately obvious to me. Plus, there isn't an Authn example. Additionally, it looks like lots of folks recommend mixing the first and second options. I can't tell what the best practice is at all, though.

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  • How can I help fellow students struggling in programming classes?

    - by David Barry
    I'm a computer science student finishing up my second semester of programming classes. I've enjoyed them quite a bit, and learned a lot, but it seems other students are struggling with the concepts and assignments more than I am. When an assignment is due, the inevitable group email comes out the day or two before with people needing some help either with a specific part of the problem, or sometimes people just seem to have a hard time knowing where to start. I'd really like to be able to help out, but I have a hard time thinking of the right way to give them help without giving them the answer. When I'm having trouble understanding a concept, a code snippet can go along way to helping me, but at the same time if it makes a lot of sense, it can be difficult to think of another way to go about it. Plus the Academic Integrity section of each assignment is always looming overhead warning against sharing code with others. I've tried using pseudo code to help give others an idea on program flow, leaving them to figure out how to implement certain aspects of it, but I didn't get too much feedback and don't know how much it actually helped them out, or if it just confused them further. So I'm basically looking to see if anyone has experience with this, or good ways that I can help out other students to nudge them in the right direction or help them think about the problem in the right way.

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  • using the :sass filter with :css

    - by corroded
    We are currently making a widget that requires some default declared styles along with it(widget html is included by javasacript, along with the default css in style tags) but the problem is i can't "chain" haml filters. What I'm trying to do is to add an internal stylesheet along with the widget like so: <style type="text/css"> p {color: #f00;} </style> <div id="widget-goes-here"> <p>etc</p> </div> We are using haml so I tried doing it with the sass filter: :sass p :color #f00 #widget-goes-here %p etc sadly, it just generated a div with a p plus the generated css code literally on top: p {color: #f00;} paragraph here I then tried using the :css filter of haml to enclose the thing in style tags(theoretically it should then turn the paragraph text color to red): :css :sass p :color #f00 #widget-goes-here %p etc But this also failed, it did generated style tags but then it just enclosed the words :sass p :color #f00 in it(it didn't parse the sass code) We did change it to :css p {color: #f00} and it worked out fine, but I still plan on doing the styling in sass(instead of plain old css) is there a way to do this?

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  • Advice on whether to use native C++ DLL or not: PINVOKE & Marshaling ?

    - by Bob
    What's the best way to do this....? I have some Native C++ code that uses a lot of Win32 calls together with byte buffers (allocated using HeapAlloc). I'd like to extend the code and make a C# GUI...and maybe later use a basic Win32 GUI (for use where there is no .Net and limited MFC support). (A) I could just re-write the code in C# and use multiple PINVOKEs....but even with the PINVOKES in a separate class, the code looks messy with all the marshaling. I'm also re-writing a lot of code. (B) I could create a native C++ DLL and use PINVOKE to marshal in the native data structures. I'm assuming I can include the native C++ DLL/LIB in a project using C#? (C) Create a mixed mode DLL (Native C++ class plus managed ref class). I'm assuming that this would make it easier to use the managed ref class in C#......but is this the case? Will the managed class handle all the marshaling? Can I use this mixed mode DLL on a platform with no .Net (i.e. still access the native C++ unmanaged component) or do I limit myself to .Net only platforms. One thing that bothers me about each of these options is all the marshalling. Is it better to create a managed data structure (array, string etc.) and pass that to the native C++ class, or, the other way around? Any ideas on what would be considered best practice...?

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  • CodeIgniter and SimpleTest -- How to make my first test?

    - by Smandoli
    I'm used to web development using LAMP, PHP5, MySQL plus NetBeans with Xdebug. Now I want to improve my development, by learning how to use (A) proper testing and (B) a framework. So I have set up CodeIgniter, SimpleTest and the easy Xdebug add-in for Firefox. This is great fun because maroonbytes provided me with clear instructions and a configured setup ready for download. I am standing on the shoulders of giants, and very grateful. I've used SimpleTest a bit in the past. Here is a the kind of thing I wrote: <?php require_once('../simpletest/unit_tester.php'); require_once('../simpletest/reporter.php'); class TestOfMysqlTransaction extends UnitTestCase { function testDB_ViewTable() { $this->assertEqual(1,1); // a pseudo-test } } $test = new TestOfMysqlTransaction(); $test->run(new HtmlReporter()) ?> So I hope I know what a test looks like. What I can't figure out is where and how to put a test in my new setup. I don't see any sample tests in the maroonbytes package, and Google so far has led me to posts that assume unit testing is already functionally available. What do I do?

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  • c++ exercise question

    - by Djecua
    in need of help on a C++ program that will help a deli owner help her customers.Prompt the user for the number of bagels.if then calculate the customers payment two ways. first it finds the price of the smallest multiple of 13 bagels that is closet to the customer's order. it then calculates the price of the customer's order so that the customer's payment is the smallest amount possible with the customer getting the exact number of bagels ordered. if the first method is the smallest amount the program outputs the number of bagels the customer will receive along with the dollar amount owed and the dollar amount saved. otherwise just print the number of bagels received the dollar amount owed $ 3.80 for a dozen bagels (13 bagels) half a dozen(6 bagels) sing bagel cost $.50 owner of the deli is a honest merchant, customers always get the best price on an order, even if they get more bagels than ordered, for example a customer that orders 10 bagels would pay $ 4.60 (2.60 for a half dozen bagels plus $2.00 for 4 single bagels.merchant gives her customer 13 bagels saving the customer $0.80 If someone can example to me how would i design to give customer extra bagels and how to calculate cost.

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  • Looking for a 'pick a-or-b' voting system script

    - by user324455
    Apologies: this is my first time on stackoverflow and I'm starting with a question and seeking advice. Sorry. Caveats: I know HTML and CSS pretty well. Javascript and PHP are not completely alien, but I'm really pretty basic on those. That said, I'm pretty sharp and willing to search for explanations independently. Ok, so my question is this: I want to create a site with a voting system very much like the one on kittenwar.com - the page loads 2 random images from a db of some sort and you click on the one you want to 'win'. Ranked pairs kind of deal. Then there is a leaderboard of those images which have the highest win-loss ratio. There also needs to be an uploader for peeps to upload their own images and have them go into an approval workflow, and from there into the db that feeds the voting thing. I tried a pre-made solution ('photo battle') but found it was completely standalone, so trying to integrate it or change any of the options was a nightmare, plus it was buggy. i'm sure there has to be a relatively easy way to do this, right? Ideally I'd like to build my site in Joomla and integrate this functionality somehow. I'd be very grateful for any advice on this. Thanks Tom

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  • Sharepoint alerts not working when multiple people are in an item

    - by csm8118
    We use Sharepoint Services 3.0 as a project tracking tool. We have a list set up that contains your basic information (description, etc.) plus we have a "assigned person" column that is of type Person or Group that we use to associate list items with individuals. This column supports multiple selections. We would like to set up alerts such that each person gets an alert email only if they are assigned to a list item. The approach we have taken is to set up a view on this list that is filtered to show list items where the assigned person equals [Me], and then to create an alert on this list that is set to send an email when someone changes an items that appears in the view. This works well when there is only one person in the assigned person column. It does not work when there is more than one person in the assigned person column. Does anybody know why this wouldn't work, or what I can do to troubleshoot? Is there a better way to achieve the end result? We could make several "assigned person" columns and not allow multiple selections, but that seems kind of kludgy.

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  • Drupal: allowing users to sign up to content using a form

    - by james6848
    My apologies if this is a little broad, but I'm struggling to know where to start here! OK, so I have a Drupal site and I need users to be able to sign up for certain content, here is the workflow in detail: I need a form within a block consisting of the following elements: First Name (required) Last Name (required) Organisation (optional) Email Address (required) Then there will be a choice of content to sign up to (using checkboxes): Policy Bulletin Action News eBulletin (which only members can sign up to) Then the usual submit button of course! Upon submission, users will: 1) Be taken to a confirmation page, or 2) Be informed about incorrectly filled in fields, and/or the need to become a user to be able to sign up for the eBulletin. Users will then receive an email when new content of the type(s) they signed up to is created, along with a link to the node. There should be details about how to unsubscribe within this email. I have used the Subscriptions module in the past, but I am not sure if it is possible to use a sign-up form with it. Plus, there is the added complexity that one of the content types, eBulletin, is only available for site members. Like I say, I'm struggling to know where to start, and any ideas would be gratefully received!

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  • Hundreds of custom UserControls create thousands of USER Objects

    - by Andy Blackman
    I'm creating a dashboard application that shows hundreds of "items" on a FlowLayoutPanel. Each "item" is a UserControl that is made up of 12 or labels. My app queries a database and then creates an "item" instance for each record, populating ethe labels and textboxes with data before adding it to the FlowLayoutPanel. After adding about 560 items to the panel, I noticed that the USER Objects count in my Task Manager had gone up to about 7300, which was much much larger than any other app on my machine. I did a quick spot of mental arithmetic (OK, I might have used calc.exe) and figured that 560 * 13 (12 labels plus the UserControl itself) is 7280. So that suddenly gave away where all the objects were coming from... Knowing that there is a 10,000 USER object limit before windows throws in the towel, I'm trying to figure better ways of drawing these items onto the FlowLayoutPanel. My ideas so far are as follows: 1) User-draw the "item", using graphics.DrawText and DrawImage in place of many of the labels. I'm hoping that this will mean 1 item = 1 USER Object, not 13. 2) Have 1 instance of the "item", then for each record, populate the instance and use the Control.DrawToBitmap() method to grab an image and then use that in the FlowLayoutPanel (or similar) So... Does anyone have any other suggestions ??? P.S. It's a zoomable interface, so I have already ruled out "Paging" as there is a requirement to see all items at once :( Thanks everyone.

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  • Cookie blocked/not saved in IFRAME in Internet Explorer

    - by Piskvor
    I have two websites, let's say they're example.com and anotherexample.net. On anotherexample.net/page.html, I have an IFRAME SRC="http://example.com/someform.asp". That IFRAME displays a form for the user to fill out and submit to http://example.com/process.asp. When I open the form ("someform.asp") in its own browser window, all works well. However, when I load someform.asp as an IFRAME in IE 6 or IE 7, the cookies for example.com are not saved. In Firefox this problem doesn't appear. For testing purposes, I've created a similar setup on http://newmoon.wz.cz/test/page.php . example.com uses cookie-based sessions (and there's nothing I can do about that), so without cookies, process.asp won't execute. How do I force IE to save those cookies? Results of sniffing the HTTP traffic: on GET /someform.asp response, there's a valid per-session Set-Cookie header (e.g. Set-Cookie: ASPKSJIUIUGF=JKHJUHVGFYTTYFY), but on POST /process.asp request, there is no Cookie header at all. Edit3: some AJAX+serverside scripting is apparently capable to sidestep the problem, but that looks very much like a bug, plus it opens a whole new set of security holes. I don't want my applications to use a combination of bug+security hole just because it's easy. Edit: the P3P policy was the root cause, full explanation below.

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  • Running code/script as a result of a form submission in ASP.NET

    - by firmbeliever
    An outside vendor did some html work for us, and I'm filling in the actual functionality. I have an issue that I need help with. He created a simple html page that is opened as a modal pop-up. It contains a form with a few input fields and a submit button. On submitting, an email should be sent using info from the input fields. I turned his simple html page into a simple aspx page, added runat=server to the form, and added the c# code inside script tags to create and send the email. It technically works but has a big issue. After the information is submitted and the email is sent, the page (which is supposed to just be a modal pop-up type thing) gets reloaded, but it is now no longer a pop-up. It's reloaded as a standalone page. So I'm trying to find out if there is a way to get the form to just execute those few lines of c# code on submission without reloading the form. I'm somewhat aware of cgi scripts, but from what I've read, that can be buggy with IIS and all. Plus I'd like to think I could get these few lines of code to run without creating a separate executable. Any help is greatly appreciated.

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  • How to .NET package JavaScript/bookmarklet as Interner Explorer 8/9 Plugin?

    - by Don
    How to .NET package JavaScript/bookmarklet as Interner Explorer 8/9 Plugin? I have recently finished writing JavaScript code for a browser addon, which basically (once the JS is included) runs on page-load, for given domains it then checks for certain elements in the DOM and adds new relevant elements(/information) to the page. Since the JavaScript only reads/affects the HTML DOM independently (and does not need any toolbar buttons or anything else) the JS purely needs adding to the browser's webpages. I have packaged the code to work with Firefox and Chrome and those are both working well, and I can run the code for IE in 'bookmarklet' form without problems, but I would like to learn how to package JavaScript as an actual .NET .MSI addon/plugin that will install for the current Internet Explorer 8/9. Does anyone know of a suitable guide or method I might refer to please? I have tried searching online for tutorials but most walkthroughs refer to writing the plugin body itself (which might involve unnecessary stages/includes) and are thus not regarding packing existing JS. I hope someone might have the solution please? Note: Someone packaged an old version for me as a MSI installer for Internet Explorer 7 a year ago, which installed into Program Files with a plugin.dll plugin.tlb and plugin.InstallState plus BandObjectLib.dll Interop.SHDocVw.dll and Microsoft.mshtml.dll if that is useful.

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  • How to learn a C++ GUI library effectively?

    - by Chan
    Hello everyone, I have many options for GUI in my head while searching in stackoverflow, but these are what I chose among others: Qt gtkmm GTK+ I used GTK+ couple years ago, and I felt so painful when using C API without string object and containers. I prefer C++ style, I then switched to C++ gtkmm, but the documentation was bad at that time. I found no help when encountering an issue. Now I want to give a hard try for Qt4, but I really want to know how to learn a GUI librarie effectively. With core C++, I usually pick up a problem and try to solve it in different ways using that particular technique, functionality. On the other hand, after skimming through the documentation from Qt site, I don't think this way of studying is applicable, since the GUI classes and APIs are so much bigger. Plus I'm still in school, so I won't have much time to play all the day long with it. How do you guys learn GUI before? Can anyone share some experiences how they learn thing, that would be an invaluable input for me! Best regards, Chan Nguyen

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  • Advantage of WPF app vs Winform for business apps?

    - by Abdu
    I know asp.net and winform development. I am not the type of developer who jumps into a new technology just because it's new. It needs to give me extra benefits like higher productivity. What are the advantages of WPF over Winforms for pure business apps? I am not interested in the extra eye candy, animation, gradients, image display effects and so on which WPF provides. The business apps are for data entry, data reporting and maybe some charts and static display of photos. How will WPF help in these apps? Better richer data binding? WinForm is a mature proven technology and I like the fact I can do everything in Visual Studio vs multiple IDE's for WPF (VS & Blend family). Plus I think WPF doesn't have as rich data binding controls like their Winform counterparts (DataGridView..etc). AFAIK, Microsoft will still support Winforms for many years. Try to convince someone like me to switch.

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  • hibernate insert to a collection causes a delete then all the items in the collection to be inserted

    - by Mark
    I have a many to may relationship CohortGroup and Employee. Any time I insert an Employee into the CohortGroup hibernate deletes the group from the resolution table and inserts all the members again, plus the new one. Why not just add the new one? The annotation in the Group: @ManyToMany(cascade = { PERSIST, MERGE, REFRESH }) @JoinTable(name="MYSITE_RES_COHORT_GROUP_STAFF", joinColumns={@JoinColumn(name="COHORT_GROUPID")}, inverseJoinColumns={@JoinColumn(name="USERID")}) public List<Employee> getMembers(){ return members; } The other side in the Employee @ManyToMany(mappedBy="members",cascade = { PERSIST, MERGE, REFRESH } ) public List<CohortGroup> getMemberGroups(){ return memberGroups; } Code snipit Employee emp = edao.findByID(cohortId); CohortGroup group = cgdao.findByID(Long.decode(groupId)); group.getMembers().add(emp); cgdao.persist(group); below is the sql reported in the log delete from swas.MYSITE_RES_COHORT_GROUP_STAFF where COHORT_GROUPID=? insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) insert into swas.MYSITE_RES_COHORT_GROUP_STAFF (COHORT_GROUPID, USERID) values (?, ?) This seams really inefficient and is causing some issues. If sevral requests are made to add an employee to the group then some get over written.

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  • Command or tool to display list of connections to a Windows file share

    - by BizTalkMama
    Is there a Windows command or tool that can tell me what users or computers are connected to a Windows fileshare? Here's why I'm looking for this: I've run into issues in the past where our deployment team has deployed BizTalk applications to one of our environments using the wrong bindings, leaving us with two receive locations pointing to the same file share (i.e. both dev and test servers point to dev receive location uri). When this occurs, the two environments in question tend to take turns processing the files received (meaning if I am attempting to debug something in one environment and the other environment has picked the file up, it looks as if my test file has disappeared into thin air). We have several different environments, plus individual developer machines, and I'd rather not have to check each individually to find the culprit. I'm looking for a quick way to detect what locations are connected to the share once I notice my test files vanishing. If I can determine the connections that are invalid, I can go directly to the person responsible for that environment and avoid the time it takes to randomly ask around. Or if the connections appear to be correct, I can go directly to troubleshooting where in the process the message gets lost. Any suggestions?

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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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  • Enterprise integration of disparate systems

    - by Chris Latta
    We're about to embark on a fairly large integration effort to kill off a bunch of Access and Sql Server databases and get everything into one coherent enterprise system. There are also a number of other systems (accounting, CRM, payroll, MS Exchange) that hold critical data that we need to integrate (use for data validation in other systems), report on and otherwise expose. It is likely that some of these systems will change in the next few years, so we need to isolate our systems to be ready for change. Ideally we would be able to expose our forms in a consistent manner across as many of our our systems as possible without having to re-develop them for each system. We are currently targeting SharePoint (2007 and soon 2010), Office (2007 and soon 2010 - Word, Excel, PowerPoint and Outlook), Reporting Services, .Net console applications, .Net Windows applications, shell extensions, and with the possibility of exposing some functionality on mobile devices (BlackBerries currently, maybe iPhones later) and via our website. We're moving development to Visual Studio 2010 (from 2005) ahead of migrating to SharePoint 2010 and Office 2010. Given that most of our development is presently targeted to the .Net framework (mostly in C#) it seems logical to stick with this unless there is some compelling reason to switch frameworks/platform for some aspects. We're thinking of your standard Database-Data Integration layer-Business Objects Layer-Web Services (or REST) layer-Client Application plus doing our own client application with WPF (or something else?) forms that can also be exposed in the MS systems (SharePoint, Office, Windows). So, we don't want much, just everything :) Basically we need to isolate ourselves from database and systems changes, create an API that can be used throughout our systems and then make this functionality available in our client applications. I'm very keen to get pointers from anyone who has tips on how to pull this off. Should we look at the Enterprise Library as a place to start? Is REST with ASP.Net MVC2 a better solution than Web Services for a system like this? Will WPF deliver forms re-use or is there something better?

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  • jQuery Ajax call for buttons on a list

    - by lloydphillips
    I have a list of data that i have in a view from an asp.net mvc application. It's a list of stock and I have two images (a plus and a minus) on the end of each row which will allow me to increase or decrease stock quantity. It works fine at present with a call to the mvc action but since the list is long I want to use jQuery and AJAX to have the call go without a refresh. I want to do this with unobtrusive javascript so don't want onclick handlers on my images. Since I'm just starting out with jQuery I have no idea how I can iterate all the images and add the function. Here are the images with the form tags as they stand: <td> <% using (Html.BeginForm("Increase", "Stock", new { Id = item.StockId })) {%> <input type="image" src="/Content/Images/bullet_add.png" style="margin-left:20px;" /> <% } %> </td> <td><% using (Html.BeginForm("Decrease", "Stock", new { Id = item.StockId })) {%> <input type="image" src="/Content/Images/bullet_delete.png" style="margin-left:10px;" /><% } %> </td> Can anyone help me out a little? Many thanks. Lloyd

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  • Optimize a views drawing code

    - by xon1c
    Hi, in a simple drawing application I have a model which has a NSMutableArray curvedPaths holding all the lines the user has drawn. A line itself is also a NSMutableArray, containing the point objects. As I draw curved NSBezier paths, my point array has the following structure: linePoint, controlPoint, controlPoint, linePoint, controlPoint, controlPoint, etc... I thought having one array holding all the points plus control points would be more efficient than dealing with 2 or 3 different arrays. Obviously my view draws the paths it gets from the model, which leads to the actual question: Is there a way to optimize the following code (inside the view's drawRect method) in terms of speed? int lineCount = [[model curvedPaths] count]; // Go through paths for (int i=0; i < lineCount; i++) { // Get the Color NSColor *theColor = [model getColorOfPath:[[model curvedPaths] objectAtIndex:i]]; // Get the points NSArray *thePoints = [model getPointsOfPath:[[model curvedPaths] objectAtIndex:i]]; // Create a new path for performance reasons NSBezierPath *path = [[NSBezierPath alloc] init]; // Set the color [theColor set]; // Move to first point without drawing [path moveToPoint:[[thePoints objectAtIndex:0] myNSPoint]]; int pointCount = [thePoints count] - 3; // Go through points for (int j=0; j < pointCount; j+=3) { [path curveToPoint:[[thePoints objectAtIndex:j+3] myNSPoint] controlPoint1:[[thePoints objectAtIndex:j+1] myNSPoint] controlPoint2:[[thePoints objectAtIndex:j+2] myNSPoint]]; } // Draw the path [path stroke]; // Bye stuff [path release]; [theColor release]; } Thanks, xonic

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  • Reduce durability in MySQL for performance

    - by Paul Prescod
    My site occasionally has fairly predictable bursts of traffic that increase the throughput by 100 times more than normal. For example, we are going to be featured on a television show, and I expect in the hour after the show, I'll get more than 100 times more traffic than normal. My understanding is that MySQL (InnoDB) generally keeps my data in a bunch of different places: RAM Buffers commitlog binary log actual tables All of the above places on my DB slave This is too much "durability" given that I'm on an EC2 node and most of the stuff goes across the same network pipe (file systems are network attached). Plus the drives are just slow. The data is not high value and I'd rather take a small chance of a few minutes of data loss rather than have a high probability of an outage when the crowd arrives. During these traffic bursts I would like to do all of that I/O only if I can afford it. I'd like to just keep as much in RAM as possible (I have a fair chunk of RAM compared to the data size that would be touched over an hour). If buffers get scarce, or the I/O channel is not too overloaded, then sure, I'd like things to go to the commitlog or binary log to be sent to the slave. If, and only if, the I/O channel is not overloaded, I'd like to write back to the actual tables. In other words, I'd like MySQL/InnoDB to use a "write back" cache algorithm rather than a "write through" cache algorithm. Can I convince it to do that? If this is not possible, I am interested in general MySQL write-performance optimization tips. Most of the docs are about optimizing read performance, but when I get a crowd of users, I am creating accounts for all of them, so that's a write-heavy workload.

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  • identifier ... is undefined when trying to run pure C code in Cuda using nvcc

    - by Lostsoul
    I'm new and learning Cuda. A approach that I'm trying to use to learn is to write code in C and once I know its working start converting it to Cuda since I read that nvcc compiles Cuda code but complies everything else using plain old c. My code works in c(using gcc) but when I try to compile it using nvcc(after changing the file name from main.c to main.cu) I get main.cu(155): error: identifier "num_of_rows" is undefined main.cu(155): error: identifier "num_items_in_row" is undefined 2 errors detected in the compilation of "/tmp/tmpxft_00002898_00000000-4_main.cpp1.ii". Basically in my main method I send data to a function like this: process_list(count, countListItem, list); the first two items are ints and the last item(list) is a matrix. Then I create my function like this: void process_list(int num_of_rows, int num_items_in_row, int current_list[num_of_rows][num_items_in_row]) { This line is where I get my errors when using nvcc(line 155). I need to convert this code to cuda anyway so no need to troubleshoot this specific issue(plus code is quite large) but I'm wondering if I'm wrong about nvcc treating the C part of your code like plain C. In the book cuda by example I just used nvcc to compile but do I need any extra flags when just using pure c?

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  • Tomcat does not pick up the class file - the JSP file is not displayed

    - by blueSky
    I have a Java code which is a controller for a jsp page, called: HomeController.java. Code is as follows: @Controller public class HomeController { protected final transient Log log = LogFactory.getLog(getClass()); @RequestMapping(value = "/mypage") public String home() { System.out.println("HomeController: Passing through..."); return "home"; } } There is nothing especial in the jsp page: home.jsp. If I go to this url: http://localhost:8080/adcopyqueue/mypage I can view mypage and everything works fine. Also in the tomcat Dos page I can see the comment: HomeController: Passing through... As expected. Now under the same directory that I have HomeController.java, I've created another file called: LoginController.java. Following is the code: @Controller public class LoginController { protected final transient Log log = LogFactory.getLog(getClass()); @RequestMapping(value = "/loginpage") public String login() { System.out.println("LoginController: Passing through..."); return "login"; } } And under the same place which I have home.jsp, I've created login.jsp. Also under tomcat folders, LoginController.class exists under the same folder that HomeController.class exists and login.jsp exists under the same folder which home.jsp exists. But when I go to this url: http://localhost:8080/adcopyqueue/loginpage Nothing is displayed! I think tomcat does not pick up LoginController.class b/c on the tomcat Dos window, I do NOT see this comment: LoginController: Passing through... Instead I see following which I do not know what do they mean? [ INFO] [http-8080-1 01:43:45] (AppInfo.java:populateAppInfo:34) got manifest [ INFO] [http-8080-1 01:43:45] (AppInfo.java:populateAppInfo:36) manifest entrie s 8 The structure and the code for HomeController.java and LoginController.java plus the jsp files match. I have no idea why tomcat sees one of the files and not the other? Clean build did not help. Does anybody have any idea? Any help is greatly appraciated.

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  • summing functions handles in matlab

    - by user552231
    Hi I am trying to sum two function handles, but it doesn't work. for example: y1=@(x)(x*x); y2=@(x)(x*x+3*x); y3=y1+y2 The error I receive is "??? Undefined function or method 'plus' for input arguments of type 'function_handle'." This is just a small example, in reality I actually need to iteratively sum about 500 functions that are dependent on each other. EDIT The solution by Clement J. indeed works but I couldn't manage to generalize this into a loop and ran into a problem. I have the function s=@(x,y,z)((1-exp(-x*y)-z)*exp(-x*y)); And I have a vector v that contains 536 data points and another vector w that also contains 536 data points. My goal is to sum up s(v(i),y,w(i)) for i=1...536 Thus getting one function in the variable y which is the sum of 536 functions. The syntax I tried in order to do this is: sum=@(y)(s(v(1),y,z2(1))); for i=2:536 sum=@(y)(sum+s(v(i),y,z2(i))) end

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