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• How can I make an even more random number in ActionScript 2.0

  - by Theo

  I write a piece of software that runs inside banner ads which generates millions of session IDs every day. For a long time I've known that the random number generator in Flash is't random enough to generate sufficiently unique IDs, so I've employed a number of tricks to get even more random numbers. However, in ActionScript 2.0 it's not easy, and I'm seeing more and more collisions, so I wonder if there is something I've overlooked. As far as I can tell the problem with Math.random() is that it's seeded by the system time, and when you have sufficient numbers of simultaneous attempts you're bound to see collisions. In ActionScript 3.0 I use the System.totalMemory, but there's no equivalent in ActionScript 2.0. AS3 also has Font.enumerateFonts, and a few other things that are different from system to system. On the server side I also add the IP address to the session ID, but even that isn't enough (for example, many large companies use a single proxy server and that means that thousands of people all have the same IP -- and since they tend to look at the same sites, with the same ads, roughly at the same time, there are many session ID collisions). What I need isn't something perfectly random, just something that is random enough to dilute the randomness I get from Math.random(). Think of it this way: there is a certain chance that two people will generate the same random number sequence using only Math.random(), but the chance of two people generating the same sequence and having, say, the exact same list of fonts is significantly lower. I cannot rely on having sufficient script access to use ExternalInterface to get hold of things like the user agent, or the URL of the page. I don't need suggestions of how to do it in AS3, or any other system, only AS2 -- using only what's available in the standard APIs. The best I've come up with so far is to use the list of microphones (Microphone.names), but I've also tried to make some fingerprinting using some of the properties in System.capabilities, I'm not sure how much randomness I can get out of that though so I'm not using that at the moment. I hope I've overlooked something.

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• OpenGL equivalent of GDI's HatchBrush or PatternBrush?

  - by Ptah- Opener of the Mouth

  I have a VB6 application (please don't laugh) which does a lot of drawing via BitBlt and the standard VB6 drawing functions. I am running up against performance issues (yes, I do the regular tricks like drawing to memory). So, I decided to investigate other ways of drawing, and have come upon OpenGL. I've been doing some experimenting, and it seems straightforward to do most of what I want; the application mostly only uses very simple drawing -- relatively large 2D rectangles of solid colors and such -- but I haven't been able to find an equivalent to something like a HatchBrush or PatternBrush. More specifically, I want to be able to specify a small monochrome pixel pattern, choose a color, and whenever I draw a polygon (or whatever), instead of it being solid, have it automatically tiled with that pattern, not translated or rotated or skewed or stretched, with the "on" bits of the pattern showing up in the specified color, and the "off" bits of the pattern left displaying whatever had been drawn under the area that I am now drawing on. Obviously I could do all the calculations myself. That is, instead of drawing as a polygon which will somehow automatically be tiled for me, I could calculate all of the lines or pixels or whatever that actually need to be drawn, then draw them as lines or pixels or whatever. But is there an easier way? Like in GDI, where you just say "draw this polygon using this brush"? I am guessing that "textures" might be able to accomplish what I want, but it's not clear to me (I'm totally new to this and the documentation I've found is not entirely obvious); it seems like textures might skew or translate or stretch the pattern, based upon the vertices of the polygon? Whereas I want the pattern tiled. Is there a way to do this, or something like it, other than brute force calculation of exactly the pixels/lines/whatever that need to be drawn? Thanks in advance for any help.

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• C# images cropping,splitting,saving

  - by cheesebunz

  Hi, as stated in subject, i have an image: private Image testing; testing = new Bitmap(@"sampleimg.jpg"); I would like to split it into 3 x 3 matrix meaning 9 images in total and save it.Any tips or tricks to do this simple? I'm using visual studios 2008 and working on smart devices. Tried some ways but i can't get it. This is what i tried: int x = 0; int y = 0; int width = 3; int height = 3; int count = testing.Width / width; Bitmap bmp = new Bitmap(width, height); Graphics g = Graphics.FromImage(bmp); for (int i = 0; i < count; i++) { g.Clear(Color.Transparent); g.DrawImage(testing, new Rectangle(0, 0, width, height), new Rectangle(x, y, width, height), GraphicsUnit.Pixel); bmp.Save(Path.ChangeExtension(@"C\AndrewPictures\", String.Format(".{0}.bmp",i))); x += width; }

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• Reducing moire when downsampling halftone comic images.

  - by drawnonward

  How can I reduce moire effects when downsampling halftone comic book images during live zoom on an iPhone or iPad? I am writing a comic book viewer. It would be nice to provide higher resolution images and allow the user to zoom in while reading the comic book. However, my client is averse to moire effects and will not allow this feature if there are noticeable moire artifacts while zooming, which of course there are. Modifying the images to be less susceptible to moire would only work if the modifications were not perceptible. Blur was specifically prohibited, as is anything that removes the beloved halftone dots. The images are black and white halftone and line art. The originals are 600 dpi but what we ship with the application will be half that at best, so probably 2500 pixels or less tall. So what are my options? If I write a custom downsampling algorithm would it be fast enough for real time on these devices? Are there other tricks I can do? Would it work to just avoid the size ratios that have the most visual moire effects? As you zoom in an out, there are definitely peaks where the moire effects are worst. Is there a way to calculate what those points are and just zoom to a nearby scale that is not as bad? Any suggestions are welcome. I have very little experience with image and signal processing, but am enjoying the opportunity to learn. I know nothing of wavelets and acutance and other jargon, so please be verbose.

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• How should I handle this Optimistic Concurrency error in this Entity Framework code, I have?

  - by Pure.Krome

  Hi folks, I have the following pseduo code in some Repository Pattern project that uses EF4. public void Delete(int someId) { // 1. Load the entity for that Id. If there is none, then null. // 2. If entity != null, then DeleteObject(..); } Pretty simple but I'm getting a run-time error:- ConcurrencyException: Store, Update, Insert or Delete statement affected an unexpected number of rows (0). Now, this is what is happening :- Two instances of EF4 are running inthe app at the same time. Instance A calls delete. Instance B calls delete a nano second later. Instance A loads the entity. Instance B also loads the entity. Instance A now deletes that entity - cool bananas. Instance B tries to delete the entity, but it's already gone. As such, the no-count or what not is 0, when it expected 1 .. or something like that. Basically, it figured out that the item it is suppose to delete, didn't delete (because it happened a split sec ago). I'm not sure if this is like a race-condition or something. Anyways, is there any tricks I can do here so the 2nd call doesn't crash? I could make it into a stored procedure.. but I'm hoping to avoid that right now. Any ideas? I'm wondering If it's possible to lock that row (and that row only) when the select is called ... forcing Instance B to wait until the row lock has been relased. By that time, the row is deleted, so when Instance B does it's select, the data is not there .. so it will never delete.

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• MySQL FULLTEXT aggravation

  - by southof40

  Hi - I'm having problems with case-sensitivity in MySQL FULLTEXT searches. I've just followed the FULLTEXT example in the MySQL doco at http://dev.mysql.com/doc/refman/5.1/en/fulltext-boolean.html . I'll post it here for ease of reference ... CREATE TABLE articles ( id INT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY, title VARCHAR(200), body TEXT, FULLTEXT (title,body) ); INSERT INTO articles (title,body) VALUES ('MySQL Tutorial','DBMS stands for DataBase ...'), ('How To Use MySQL Well','After you went through a ...'), ('Optimizing MySQL','In this tutorial we will show ...'), ('1001 MySQL Tricks','1. Never run mysqld as root. 2. ...'), ('MySQL vs. YourSQL','In the following database comparison ...'), ('MySQL Security','When configured properly, MySQL ...'); SELECT * FROM articles WHERE MATCH (title,body) AGAINST ('database' IN NATURAL LANGUAGE MODE); ... my problem is that the example shows that SELECT returning the first and fifth rows ('..DataBase..' and '..database..') but I only get one row ('database') ! The example doesn't demonstrate what collation the table in the example had but I have ended up with latin1_general_cs on the title and body columns of my example table. My version of MySQL is 5.1.39-log and the connection collation is utf8_unicode_ci . I'd be really grateful is someone could suggest why my experience differs from the example in the manual ! Be grateful for any advice.

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• Automatic testing of GUI related private methods

  - by Stein G. Strindhaug

  When it comes to GUI programming (at least for web) I feel that often the only thing that would be useful to unit test is some of the private methods*. While unit testing makes perfect sense for back-end code, I feel it doesn't quite fit the GUI classes. What is the best way to add automatic testing of these? * Why I think the only methods useful to test is private: Often when I write GUI classes they don't even have any public methods except for the constructor. The public methods if any is trivial, and the constructor does most of the job calling private methods. They receive some data from server does a lot of trivial output and feeds data to the constructor of other classes contained inside it, adding listeners that calls a (more or less directly) calls the server... Most of it pretty trivial (the hardest part is the layout: css, IE, etc.) but sometimes I create some private method that does some advanced tricks, which I definitely do not want to be publicly visible (because it's closely coupled to the implementation of the layout, and likely to change), but is sufficiently complicated to break. These are often only called by the constructor or repeatedly by events in the code, not by any public methods at all. I'd like to have a way to test this type of methods, without making it public or resorting to reflection trickery. (BTW: I'm currently using GWT, but I feel this applies to most languages/frameworks I've used when coding for GUI)

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• How do the size standard libraries compare for different languages

  - by Roman A. Taycher

  Someone was recently raving about how great jQuery was and how it made javascript into a pleasure and also how the whole source code was so small(and one file). I looked it up on www.ohloh.net/ and it said it was about 30,000 lines of javascript, when I tired curl piped to wc it said about 5000 lines(strange discrepancy that, maybe test suites, ect?). I thought well it isn't that strange since javascript from what I've heard has a lot of fun dynamic tricks, so you can probably get away with a small library. But then I thought what about other high level languages, the ones with large standard libraries and wondered how big the standard are for python/ruby/haskell/pharo(smalltalk)/*ml/ect. (libraries not vm stuff to the degree its possible to separate it) Anybody know? Any details (comment/blank/code lines , test code lines, lines in language vs lines in ffi/byte-code) are appreciated! edit: ps. since it started this me asking about jQuery as a bonus if you could please list the size of mega frameworks, a megaframewok provides so much that people using an x megaframework in language y might sometimes refer to programming in xy or even x rather then in y (ie. : qt, jQuery, etc.).

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• HTML5 Shiv not parsing quick enough

  - by Mikey Hogarth

  One of our web designers is working on a site at the moment and is using HTML5 elements, which she styles up in older browsers using the well documented Html5Shiv; http://css-tricks.com/html5-innershiv/ She reported some pretty weird behavior today and it looks like this is the cause. Initially it was very confusing, and went something along the lines of; "The page looks fine, I refresh it looks fine, refresh several times and occasionally it will not apply my styles to the HTML5 elements" Current best theory is that the shiv is not kicking in quick enough, and the page loads before the new elements have been registered. I was wondering if anyone could suggest a surefire way of including the shiv and making sure it's loaded and been parsed BEFORE the rest of the elements, so they will definitely get styled. EDIT (more info) Shiv is being included in the head, directly below the title/meta tags; <!--[if IE]> <script type="text/javascript" src="http://html5shiv.googlecode.com/svn/trunk/html5.js"></script> <![endif]--> The bit that is being styled is in the footer and is cross-site. Many of the pages will change in size as they're being powered by a CMS that our marketing team will use so I am unable to give an exact page size. All I would say is that if page size is an issue and there is no workaround, can someone let me know as this will mean we basically can't use HTML5 on this project (or at the very least we'll need to add superflous markup such as divs to ensure that the layout doesn't go crazy) EDIT 2 There is no chance of me posting the code unfortunately - it's only re-creatable under really obscure circumstances and the project is marked "top secret" at the moment :( If nobody knows then I'm guessing it's either a case of "everyone knows it happens but kinda ignores it" or just that it's something else other than the shiv.

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• How did your team customize Stylecop (and perhaps other tools) for .Net for a good result?

  - by Hamish Grubijan

  Our team is still in a love / hate relationship with it. I am hoping to put an end to the debate by having an internal vote on what rules should be excluded and which rules should be added. Before doing so, I wanted to ask others SO users. To standardize (but not limit) the responses: What is your current StyleCop version? What .Net version do you currently target? Which default rules did you turn off? Which non-default rules have you turned on? Have you coded your own rules? Please describe. Do you have any other StyleCop tricks worth sharing? Do you use Resharper? What version? Is it a good bang for the buck? Do you use any other tools for .Net / C++ which integrate with Visual Studio and aid development? Did you get your money's worth? Anything else you like to add? ... Thank you!

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• Sequential animations in Jquery

  - by Pickels

  I see a lot people struggling with this(me included). I guess it's mostly due to not perfectly knowing how Javascript scopes work. An image slideshow is a good example of this. So lets say you have series of images, the first one fades in = waits = fades out = next image. When I first created this I was already a little lost. I think the biggest problem for creating the basics is to keep it clean. I noticed working with callbacks can get uggly pretty fast. So to make it even more complicated most slideshows have control buttons. Next, previous, go to img, pause, ... I've been trying this for a while now and this is where I got: $(InitSlideshow); function InitSlideshow() { var img = $("img").hide(); var animate = { wait: undefined, start: function() { img.fadeIn(function() { animate.middle(); }); }, middle: function() { animate.wait = setTimeout(function() { animate.end(); }, 1000); }, end: function() { img.fadeOut(function() { animate.start(); }); }, stop: function() { img.stop(); clearTimeout(animate.wait); } }; $("#btStart").click(animate.start); $("#btStop").click(animate.stop); }; This code works(I think) but I wonder how other people deal with sequentials animations in Jquery? Tips and tricks are most welcome. So are links to good resources dealing with this issue. If this has been asked before I will delete this question. I didn't find a lot of info about this right away. I hope making this community wiki is correct as there is not one correct answer to my question. Kind regards, Pickels

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• Find the Algorithm that generates the checksum

  - by knivmannen

  I have a sensing device that transmits a 6-byte message along with an 1-byte counter and supposely a checksum. The data looks something like this: ------DATA----------- -Counter- --Checksum?-- 55 FF 00 00 EC FF ---- 60---------- 1F The last four bits in the counter are always set 0, i.e those bits are probably not used. The last byte is assumed to be the checksum since it has a quite peculiar nature. It tends to randomly change as data changes. Now what i need is to find the algorithm to compute this checksum based on --DATA--. what i have tried is all possible CRC-8 polynomials, for each polynomial i have tried to reflect data, toggle it, initiate it with non-zeroes etc etc. Ive come to the conclusion that i am not dealing with a normal crc-algorithm. I have also tried some flether and adler methods without succes, xor stuff back and forth but still i have no clue how to generate the checksum. My biggest concern is, how is the counter used??? Same data but with different countervalue generates different checksums. I have tried to include the counter in my computations but without any luck. Here are some other datasamples: 55 FF 00 00 F0 FF A0 38 66 0B EA FF BF FF C0 CA 5E 18 EA FF B7 FF 60 BD F6 30 16 00 FC FE 10 81 One more thing that might be worth mentioning is that the last byte in the data only takes on the values FF or FE Plz if u have any tips or tricks that i may try post them here, I am truly desperate. Thx

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• Delphi : Handling the fact that Strings are not Objects

  - by awmross

  I am trying to write a function that takes any TList and returns a String representation of all the elements of the TList. I tried a function like so function ListToString(list:TList<TObject>):String; This works fine, except you can't pass a TList to it. E2010 Incompatible types: 'TList<System.TObject>' and 'TList<System.string>' In Delphi, a String is not an Object. To solve this, I've written a second function: function StringListToString(list:TList<string>):String; Is this the only solution? Are there other ways to treat a String as more 'object-like'? In a similar vein, I also wanted to write an 'equals' function to compare two TLists. Again I run into the same problem function AreListsEqual(list1:TList<TObject>; list2:TList<TObject>):boolean; Is there any way to write this function (perhaps using generics?) so it can also handle a TList? Are there any other tricks or 'best practises' I should know about when trying to create code that handles both Strings and Objects? Or do I just create two versions of every function? Can generics help? I am from a Java background but now work in Delphi. It seems they are lately adding a lot of things to Delphi from the Java world (or perhaps the C# world, which copied them from Java). Like adding equals() and hashcode() to TObject, and creating a generic Collections framework etc. I'm wondering if these additions are very practical if you can't use Strings with them.

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• jQuery .trigger() or $(window) not working in Google Chrome

  - by Jonathan

  I have this jQuery ajax navigation tabs plugin that I created using some help from CSS-Tricks.com and the jQuery hashchange event plugin (detects hash changes in browsers that don't support it). The code is little long to post it here but it goes something like this: Part 1) When a tab is clicked, it gets the href attribute of that tab and add it to the browsers navigation bar like '#tab_name': window.location.hash = $(this).attr("href"); Part 2) When the navigation bar changes (hash change), it gets the href change like this: window.location.hash.substring(1); (substring is to get only 'tab_name' without the '#'), and then call the ajax function to get the info to display. I want to automatically trigger the plugin to load the first tab when the page is accessed, so at the start of the code I put: if (window.location.hash === '') { // If no '#' is in the browser navigation bar window.location.hash = '#tab_1'; // Add #tab_1 to the navigation bar $(window).trigger('hashchange'); // Trigger a hashchange so 'Part 2' of the plugin calls the ajax function using the '#tab_1' added } The probles is that it works in FF but not in Chrome, I mean, everything works but it seems like the $(window).trigger('hashchange'); is not working because it doesnt get the first tab.. Any suggestions??

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• Automated Legal Processing

  - by Chris S

  Will it ever be possible to make legal systems quantifiable enough to process with computer algorithms? What technologies would have to be in place before this is possible? Are there any existing technologies that are already trying to accomplish this? Out of curiosity, I downloaded the text for laws in my local municipality, and tried applying some simple NLP tricks to extract rules from sentences. I had mixed results. Some sentences were very explicit (e.g. "Cars may not be left in the park overnight"), but other sentences seemed hopelessly vague (e.g. "The council's purpose is to ensure the well-being of the community"). I apologize if this is too open-ended a topic, but I've often wondered what society would look like if legal systems were based on less ambiguous language. Lawyers, and the legal process in general, are so expensive because they have to manually process a complex set of rules codified in ambiguous legal texts. If this system could be represented in software, this huge expense could potentially be eliminated, making the legal system more accessible for everyone.

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• Vim step-by-step: How do you line up arbitrary text by arbitrary delimiter?

  - by dreftymac

  Background: There are a lot of great tutorials and "tricks" pages for Vim, but one thing that is very difficult is to find specific instructions on how to do some arbitrary thing that one can easily do in one's own familiar text editor IDE. Therefore I am asking for step by step instructions on how you I would do something in Vim that I already know how to do in other text editors. I like Vim and the great built-in help and numerous on-line tutorials, but sometimes a human has to break down and ask another human. Question: Suppose I have the following code in my file, how can I use Vim to get from BEFORE, to AFTER? BEFORE: Lorem ipsum dolor | sit amet, consectetur | adipisicing elit, sed do eiusmod | tempor incididunt | ut labore et | dolore magna aliqua. | Ut enim ad minim veniam, quis nostrud | exercitation ullamco | laboris nisi ut | aliquip ex ea commodo | consequat. Duis aute irure AFTER: Lorem ipsum dolor | sit amet, consectetur | adipisicing elit, sed do eiusmod | tempor incididunt | ut labore et | dolore magna aliqua. | Ut enim ad minim veniam, quis nostrud | exercitation ullamco | laboris nisi ut | aliquip ex ea commodo | consequat. Duis aute irure

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• Can I add a portrait layout on top of a landscape Camera SurfaceView?

  - by Uwe Krass

  My application should hold a camera preview surface. The camera is fixed to landscape view via AndroidMainfest.xml <application android:icon="@drawable/icon" android:label="Camera"> <uses-library android:name="com.google.android.maps" /> <uses-feature android:name="android.hardware.camera" /> <uses-feature android:name="android.hardware.camera.autofocus" /> <activity android:name=".CameraPreview" android:label="Camera" android:screenOrientation="landscape"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> If there is another way to get the camera preview itself to behave correctly, please let me know. Now I need to have an overlay that holds a bunch of buttons. Due to usability, the user interface should be set to portrait view (or even better orientation aware). Is there a way to have a transparent layout (for buttons and other GUI elements) in portrait orientation? I tried to write a special rotated layout by extending a RelativeLayout, but the onDraw method isn't called at anytime. public class RotatedOverlay extends RelativeLayout { private static final String TAG = "RotatedOverlay"; public RotatedOverlay(Context context, AttributeSet attrs ) { super(context, attrs); } @Override protected void onDraw(Canvas canvas) { canvas.rotate(90); super.onDraw(canvas); } I am quite new to the Android plattform programming. Of course I dont know much about the programming tricks and workarounds yet. I did a lot of research over the last two weeks (even studied the native Camera implementation), but couldnt find a good solution so far. Maybe it works with two seperate Activities, but I dont think, that this can the right solution.

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• Git-Based Source Control in the Enterprise: Suggested Tools and Practices?

  - by Bob Murphy

  I use git for personal projects and think it's great. It's fast, flexible, powerful, and works great for remote development. But now it's mandated at work and, frankly, we're having problems. Out of the box, git doesn't seem to work well for centralized development in a large (20+ developer) organization with developers of varying abilities and levels of git sophistication - especially compared with other source-control systems like Perforce or Subversion, which are aimed at that kind of environment. (Yes, I know, Linus never intended it for that.) But - for political reasons - we're stuck with git, even if it sucks for what we're trying to do with it. Here are some of the things we're seeing: The GUI tools aren't mature Using the command line tools, it's far to easy to screw up a merge and obliterate someone else's changes It doesn't offer per-user repository permissions beyond global read-only or read-write privileges If you have a permission to ANY part of a repository, you can do that same thing to EVERY part of the repository, so you can't do something like make a small-group tracking branch on the central server that other people can't mess with. Workflows other than "anything goes" or "benevolent dictator" are hard to encourage, let alone enforce It's not clear whether it's better to use a single big repository (which lets everybody mess with everything) or lots of per-component repositories (which make for headaches trying to synchronize versions). With multiple repositories, it's also not clear how to replicate all the sources someone else has by pulling from the central repository, or to do something like get everything as of 4:30 yesterday afternoon. However, I've heard that people are using git successfully in large development organizations. If you're in that situation - or if you generally have tools, tips and tricks for making it easier and more productive to use git in a large organization where some folks are not command line fans - I'd love to hear what you have to suggest. BTW, I've asked a version of this question already on LinkedIn, and got no real answers but lots of "gosh, I'd love to know that too!"

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• Why would this Lua optimization hack help?

  - by Ian Boyd

  i'm looking over a document that describes various techniques to improve performance of Lua script code, and i'm shocked that such tricks would be required. (Although i'm quoting Lua, i've seen similar hacks in Javascript). Why would this optimization be required: For instance, the code for i = 1, 1000000 do local x = math.sin(i) end runs 30% slower than this one: local sin = math.sin for i = 1, 1000000 do local x = sin(i) end They're re-declaring sin function locally. Why would this be helpful? It's the job of the compiler to do that anyway. Why is the programmer having to do the compiler's job? i've seen similar things in Javascript; and so obviously there must be a very good reason why the interpreting compiler isn't doing its job. What is it? i see it repeatedly in the Lua environment i'm fiddling in; people redeclaring variables as local: local strfind = strfind local strlen = strlen local gsub = gsub local pairs = pairs local ipairs = ipairs local type = type local tinsert = tinsert local tremove = tremove local unpack = unpack local max = max local min = min local floor = floor local ceil = ceil local loadstring = loadstring local tostring = tostring local setmetatable = setmetatable local getmetatable = getmetatable local format = format local sin = math.sin What is going on here that people have to do the work of the compiler? Is the compiler confused by how to find format? Why is this an issue that a programmer has to deal with? Why would this not have been taken care of in 1993? i also seem to have hit a logical paradox: Optimizatin should not be done without profiling Lua has no ability to be profiled Lua should not be optimized

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• Why does C++ not allow multiple types in one auto statement?

  - by Walter

  The 2011 C++ standard introduced the new keyword auto, which can be used for defining variables instead of a type, i.e. auto p=make_pair(1,2.5); // pair<int,double> auto i=std::begin(c), end=std::end(c); // decltype(std::begin(c)) In the second line, i and end are of the same type, referred to as auto. The standard does not allow auto i=std::begin(container), e=std::end(container), x=*i; when x would be of different type. My question: why does the standard not allow this last line? It could be allowed by interpreting auto not as representing some to-be-decuded type, but as indicating that the type of any variable declared auto shall be deduced from its assigned value. Is there any good reason for the C++11 standard to not follow this approach? There is actually a use case for this, namely in the initialisation statement of for loops: for(auto i=std::begin(c), end=std::end(c), x=*i; i!=end; ++i, x+=*i) { ... } when the scope of the variables i, end, and x is limited to the for loop. AFAIK, this cannot be achieved in C++ unless those variables have a common type. Is this correct? (ugly tricks of putting all types inside a struct excluded) There may also be use cases in some variadic template applications.

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• Passing information safely between Wicket and Hibernate in long running conversations

  - by Peter Tillemans

  We are using Wicket with Hibernate in the background. As part of out UI we have quite long running conversations spanning multiple requests before the updated information is written back to the database. To avoid getting hibernate errors with detached objects we are now using value objects to transfer info from the service layer to Wicket. However we now end up with an explosion of almost the same objects : e.g. Answer (mapped entity saved in hibernate) AnswerVO (immutable value object) AnswerModel (A mutable bean in the session domain) IModel wrapped Wicket Model and usually this gets wrapped in a CompoundPropertyModel This plumbing becomes exponentially worse when collections to other objects are involved in the objects. There has to be a better way to organize this. Can anyone share tips to make this less onerous? Maybe make the value objects mutable so we can remove the need for a seaprate backing bean in Wicket? Use the entity beans but absolutely make dead-certain they are detached from hibernate. (easier said than done)? Some other tricks or patterns?

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• Rails: creating a custom data type, to use with generator classes and a bunch of questions related t

  - by Shyam

  Hi, After being productive with Rails for some weeks, I learned some tricks and got some experience with the framework. About 10 days ago, I figured out it is possible to build a custom data type for migrations by adding some code in the Table definition. Also, after learning a bit about floating points (and how evil they are) vs integers, the money gem and other possible solutions, I decided I didn't WANT to use the money gem, but instead try to learn more about programming and finding a solution myself. Some suggestions said that I should be using integers, one for the whole numbers and one for the cents. When playing in script/console, I discovered how easy it is to work with calculations and arrays. But, I am talking to much (and the reason I am, is to give some sufficient background). Right now, while playing with the scaffold generator (yes, I use it, because I like they way I can quickly set up a prototype while I am still researching my objectives), I like to use a DRY method. In my opinion, I should build a custom "object", that can hold two variables (Fixnum), one for the whole, one for the cents. In my big dream, I would be able to do the following: script/generate scaffold Cake name:string description:text cost:mycustom Where mycustom should create two integer columns (one for wholes, one for cents). Right now I could do this by doing: script/generate scaffold Cake name:string description:text cost_w:integer cost_c:integer I had also had an idea that would be creating a "cost model", which would hold two columns of integers and create a cost_id column to my scaffold. But wouldn't that be an extra table that would cause some kind of performance penalty? And wouldn't that be defy the purpose of the Cake model in the first place, because the costs are an attribute of individual Cake entries? The reason why I would want to have such a functionality because I am thinking of having multiple "costs" inside my rails application. Thank you for your feedback, comments and answers! I hope my message got through as understandable, my apologies for incorrect grammar or weird sentences as English is not my native language.

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• How to hide the console of batch scripts without losing std err/out streams

  - by cooper.thompson

  My question is similar to Running a CMD or BAT in silent mode, but with one additional constraint. If you use WshScript.Run in vbscript, you lose access to the standard in/error/out streams of the process. WshScript.Exec gives you access to the standard streams, but you can't hide your windows. How can you have your cake (hide the windows) and eat it too (have direct access to the console streams)? I'm currently thinking about a C++ executable which creates a new Windows Station and Desktop, (see MSDN) and runs a specified script within that new Desktop (I'm not yet an expert on Window Stations and Desktops, so this idea may be retarded). This idea is based loosely on Condor's USE_VISIBLE_DESKTOP feature, which, if disabled, runs Condor jobs in a non-visible Desktop. I haven't quite figured out if this requires elevated priveledge. The tradeoff of this approach is that your script can disappear into limbo if it blocks on user input. Does anyone have any additional ideas? Or feedback on the approach outlined above? Edit: Also, the purpose of our script is to set up the user environment, so running as another user, or as a system scheduled task isn't really an option (unless there are clever tricks I don't know about).

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• Career day in kindergarten

  - by Péter Török

  I was invited to the kindergarten group of my elder daughter to talk and answer the kids' questions about my profession. There are 26 kids of age 4-6 in the group, plus 3 teachers who are fairly scared of anything related to programming and IT themselves, but bold enough to learn new tricks. I would have about 20-30 minutes, without projector or anything. They have an old computer though, which by its look may be a 486, and I am not even sure if it's functioning. My research turned up excellent earlier threads, with lots of good tips: How would you explain your job to a 5-year old? Career Day: how do I make “computer programmer” sound cool to 8 year olds? What things can I teach a group of children about programming in one day? My situation is different from each of the above though: the latter ones are concerned with older children, while the first one is about talking to a single kid (or elder person)—a group of 20 is a whole different challenge. How can I teach the kids and their teachers about programming in a fun way?

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• Is the REST support in Spring 3's MVC Framework production quality yet?

  - by glenjohnson

  Hi all, Since Spring 3 was released in December last year, I have been trying out the new REST features in the MVC framework for a small commercial project involving implementing a few RESTful Web Services which consume XML and return XML views using JiBX. I plan to use either Hibernate or JDBC Templates for the data persistence. As a Spring 2.0 developer, I have found Spring 3's (and 2.5's) new annotations way of doing things quite a paradigm shift and have personally found some of the new MVC annotation features difficult to get up to speed with for non-trivial applications - as such, I am often having to dig for information in forums and blogs that is not apparent from going through the reference guide or from the various Spring 3 REST examples on the web. For deadline-driven production quality and mission critical applications implementing a RESTful architecture, should I be holding off from Spring 3 and rather be using mature JSR 311 (JAX-RS) compliant frameworks like RESTlet or Jersey for the REST layer of my code (together with Spring 2 / 2.5 to tie things together)? I had no problems using RESTlet 1.x in a previous project and it was quite easy to get up to speed with (no magic tricks behind the scenes), but when starting my current project it initially looked like the new REST stuff in Spring 3's MVC Framework would make life easier. Do any of you out there have any advice to give on this? Does anyone know of any commercial / production-quality projects using, or having successfully delivered with, the new REST stuff in Spring 3's MVC Framework. Many thanks Glen

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