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• Why Aren't Programs Written In Assembly More Often?

  - by mudge

  It seems to be a mainstream opinion that assembly programming takes longer and is more difficult to program in than a higher level language such as C. Therefore it seems to be recommend or assumed that it is better to write in a higher level language for these reasons and for the reason of better portability. Recently I've been writing in x86 assembly and it has dawned on me that perhaps these reasons are not really true, except perhaps portability. Perhaps it is more of a matter of familiarity and knowing how to write assembly well. I also noticed that programming in assembly is quite different than programming in an HLL. Perhaps a good and experienced assembly programmer could write programs just as easily and as quickly as an experienced C programmer writing in C. Perhaps it is because assembly programming is quite different than HLLs, and so requires different thinking, methods and ways, which makes it seem very awkward to program in for the unfamiliar, and so gives it its bad name for writing programs in. If portability isn't an issue, then really, what would C have over a good assembler such as NASM?

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• Setting left/top position not working in IE

  - by Brian

  Hello, In a custom ASP.NET AJAX control, i have this to do some repositioning. var dims = Sys.UI.DomElement.getBounds(control); this.get_element().style.position = "absolute"; //Sys.UI.DomElement.setLocation(this.get_element(), dims.x, (dims.y + dims.height)); this.get_element().style.left = dims.x; this.get_element().style.top = (dims.y + dims.height); getBounds simply returns the x/y and width/height. I use this to set the left/top, but in IE, it's doubling; say the coordinates are 500, 20; when it sets this on the element, its actually setting to 1000, 40. Any ideas why? In firefox, this works correctly. this.get_element() returns the correct element and all, but it's not setting correctly, even though event logging says it's the correct coordinates. When using setLocation too, it doesn't work in either... What else in my code may be affecting it? JQuery isn't an option here too. Thanks.

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• Should I use a regular server instead of AWS?

  - by Jon Ramvi

  Reading about and using the Amazon Web Services, I'm not really able to grasp how to use it correctly. Sorry about the long question: I have a EC2 instance which mostly does the work of a web server (apache for file sharing and Tomcat with Play Framework for the web app). As it's a web server, the instance is running 24/7. It just came to my attention that the data on the EC2 instance is non persistent. This means I lose my database and files if it's stopped. But I guess it also means my server settings and installed applications are lost as they are just files in the same way as the other data. This means that I will either have to rewrite the whole app to use amazon CloudDB or write some code which stores the db on S3 and make my own AMI with the correct applications installed and configured. Or can this be quick-fixed by using EBS somehow? My question is 1. is my understanding of aws is correct? and 2. is it's worth it? It could be a possibility to just set up a regular dedicated server where everything is persistent, as you would expect. Would love to have the scaleability of aws though..

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• Difference between float and double

  - by VaioIsBorn

  I know, i've read about the difference between double precision and single precision etc. But they should give the same results on most cases right ? I was solving a problem on a programming contest and there were calculations with floating point numbers that were not really big so i decided to use float instead of double, and i checked it - i was getting the correct results. But when i send the solution, it said only 1 of 10 tests was correct. I checked again and again, until i found that using float is not the same using double. I put double for the calculations and double for the output, and the program gave the SAME results, but this time it passed all the 10 tests correctly. I repeat, the output was the SAME, the results were the SAME, but putting float didn't work - only double. The values were not so big too, and the program gave the same results on the same tests both with float and double, but the online judge accepted only the double-provided solution. Why ? What is the difference ?

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• Hibernate/JPA DB Schema Generation Best Practices

  - by Bytecode Ninja

  I just wanted to hear the opinion of Hibernate experts about DB schema generation best practices for Hibernate/JPA based projects. Especially: What strategy to use when the project has just started? Is it recommended to let Hibernate automatically generate the schema in this phase or is it better to create the database tables manually from earliest phases of the project? Pretending that throughout the project the schema was being generated using Hibernate, is it better to disable automatic schema generation and manually create the database schema just before the system is released into production? And after the system has been released into production, what is the best practice for maintaining the entity classes and the DB schema (e.g. adding/renaming/updating columns, renaming tables, etc.)? Thanks in advance.

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• unable to return 'true' value in C function

  - by Byron

  If Im trying to check an input 5 byte array (p) against a 5 byte array stored in flash (data), using the following function (e2CheckPINoverride), to simply return either a true or false value. But it seems, no matter what I try, it only returns as 'false'. I call the function here: if (e2CheckPINoverride(pinEntry) == 1){ PTDD_PTDD1 = 1; } else{ PTDD_PTDD1 = 0; } Here is the function: BYTE e2CheckPINoverride(BYTE *p) { BYTE i; BYTE data[5]; if(e2Read(E2_ENABLECODE, data, 5)) { if(data[0] != p[0]) return FALSE; if(data[1] != p[1]) return FALSE; if(data[2] != p[2]) return FALSE; if(data[3] != p[3]) return FALSE; if(data[4] != p[4]) return FALSE; } return TRUE; } I have already assigned true and false in the defines.h file: #ifndef TRUE #define TRUE ((UCHAR)1) #endif #ifndef FALSE #define FALSE ((UCHAR)0) #endif and where typedef unsigned char UCHAR; when i step through the code, it performs all the checks correctly, it passes in the correct value, compares it correctly and then breaks at the correct point, but is unable to process the return value of true? please help?

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• C# regular expression for finding forms with input tags in HTML?

  - by johnrl

  Hi all. I have a simple problem: I want to construct a regex that matches a form in HTML, but only if the form has any input tags. Example: The following should be matched (ignoring attributes): .. <form> .. <input/> .. </form> .. But the following should not (ignoring attributes): .. <form> .. </form> .. I have tried everything from look-arounds to capture groups but it quickly gets complicated. I want to believe there is a simple regex to capture the problem. Please note that it is important that the regex pairs the opening and closing tags according to the HTML code which means the following does not work: <form>.+<input/>.+</form> because it matches wrongly like this: .. <form> <--- This is wrongly matched as the opening tag .. </form> <form> <-- This is the correct opening tag of the correct form .. <input/> .. </form> <--- This is matched as the closing tag ..

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• How to properly implement the Strategy pattern in a web MVC framework?

  - by jboxer

  In my Django app, I have a model (lets call it Foo) with a field called "type". I'd like to use Foo.type to indicate what type the specific instance of Foo is (possible choices are "Number", "Date", "Single Line of Text", "Multiple Lines of Text", and a few others). There are two things I'd like the "type" field to end up affecting; the way a value is converted from its normal type to text (for example, in "Date", it may be str(the_date.isoformat())), and the way a value is converted from text to the specified type (in "Date", it may be datetime.date.fromtimestamp(the_text)). To me, this seems like the Strategy pattern (I may be completely wrong, and feel free to correct me if I am). My question is, what's the proper way to code this in a web MVC framework? In a client-side app, I'd create a Type class with abstract methods "serialize()" and "unserialize()", override those methods in subclasses of Type (such as NumberType and DateType), and dynamically set the "type" field of a newly-instantiated Foo to the appropriate Type subclass at runtime. In a web framework, it's not quite as straightforward for me. Right now, the way that makes the most sense is to define Foo.type as a Small Integer field and define a limited set of choices (0 = "Number", 1 = "Date", 2 = "Single Line of Text", etc.) in the code. Then, when a Foo object is instantiated, use a Factory method to look at the value of the instance's "type" field and plug in the correct Type subclass (as described in the paragraph above). Foo would also have serialize() and unserialize() methods, which would delegate directly to the plugged-in Type subclass. How does this design sound? I've never run into this issue before, so I'd really like to know if other people have, and how they've solved it.

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• JTable data only shown after scrolling

  - by Christian 'fuzi' Orgler

  I wrote a method, that creates my DefaultTableModel and there I'm going to add my records. When I set the model to my JTable, the data rows are blank. After scrolling the data gets displayed correct. How can I avoid this and display the data from the first moment? EDIT: I imported the javax.swing.table.DefaultTableModel -- is this correct? private DefaultTableModel _dtm; private void loadTable(Vector<Member> members) { loadTableModel(); try { lbl_state.setText("Please wait"); for (Member actMember : members) { String gender = ""; if (actMember.getGender() == MemberView.MEMBER_MALE) { gender = "männlich"; } else { gender = "weiblich"; } _dtm.addRow(new Object[]{ actMember.getNname(), actMember.getVname(), actMember.getCity(), actMember.getStreet(), actMember.getPlz(), actMember.getMail(), actMember.getPhonenumber(), actMember.getBirthdayString(), actMember.getStartDateString(), gender, actMember.getBankname(), actMember.getAccountnumber(), actMember.getBanknumber(), actMember.getGroup().toString(), (actMember.hasAccess() ? "JA" : "NEIN"), actMember.getWriteDateString(), (actMember.hasDrinkAbo() ? "JA" : "NEIN") }); } } catch (Exception ex) { System.err.println(ex.getMessage()); } tbl_results.setModel(_dtm); } private void loadTableModel() { _dtm = new DefaultTableModel(new Object[]{"Nachname", "Vorname", "Ort", "Straße", "PLZ", "E-Mail", "Telefon", "Geburtsdatum", "Beitrittsdatum", "Geschlecht", "Bankname", "Kontonummer", "Bankleitzahl", "Gruppe", "hat Zugriff", "Einschreibdatum", "Getränkeabo"}, 0); tbl_results.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS); }

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• Programming languages: out of the box legibility and extensibility

  - by sova

  Two excellent results of SOLID development ideology are - Legibility - Extensibility over the life of a project (http://en.m.wikipedia.org/wiki/Solid_(object-oriented_design) Although SOLID is a set of language-agnostic design ideas, some languages inherently support these ideas better than others. Out-of-the-box or after various customizations, in your opinion which language is best-suited to be both easily readable and easy to extend functionality in? Some definitions to pre-empt biases and flamewars: Legibility: amount of thinking done to understand the code proportional to the amount of code: (amount_think-energy / amount_code) is fairly constant and as low as possible in the optimal case. Extensibility: Addition of X amount of functionality requires a change in code or code additions in proportion to X (amount_added_functionality / amount_added_code) is fairly constant and as high as possible in the optimal case. Supporting information and tutorials encouraged. Code snippets welcome.

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• Usability: Save changes using "Apply" button or after every single change?

  - by mr.b

  I am interested in hearing opinions and experiences of fellow developers on topic of designing user interface, usability AND maintainability-wise. Common approach is to allow users to tweak options and after form gets "dirty", enable "Apply" button, and user has possibility to back out by pressing cancel. This is most common approach on Windows platform (I believe MS usability guidelines say to do so as well). Another way is to apply changes after every single change has been made to options. Example, user checks some checkbox, and change is applied. User changes value of some text box, and change is applied after box looses focus, etc. You get the point. This approach is most common on Mac OSX. Regardless of my personal opinion (which is that Apple is better at usability, but software I usually write targets Windows users), what do you people think?

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• WSACONNREFUSED when connecting to server

  - by Robert Mason

  I'm currently working on a server. I know that the client side is working (I can connect to www.google.com on port 80, for example), but the server is not functioning correctly. The socket has socket()ed, bind()ed, and listen()ed successfully and is on an accept loop. The only problem is that accept() doesn't seem to work. netstat shows that the server connection is running fine, as it prints the PID of the server process as LISTENING on the correct port. However, accept never returns. Accept just keeps running, and running, and if i try to connect to the port on localhost, i get a 10061 WSACONNREFUSED. I tried looping the connection, and it just keeps refusing connections until i hit ctrl+c. I put a breakpoint directly after the call to accept(), and no matter how many times i try to connect to that port, the breakpoint never fires. Why is accept not accepting connections? Has anyone else had this problem before? Known: [breakpoint0] if ((new_fd = accept(sockint, NULL, NULL)) == -1) { throw netlib::error("Accept Error"); //netlib::error : public std::exception } else { [breakpoint1] code...; } breakpoint0 is reached (and then continued through), no exception is thrown, and breakpoint1 is never reached. The client code is proven to work. Netstat shows that the socket is listening. If it means anything, i'm connecting to 127.0.0.1 on port 5842 (random number). The server is configured to run on 5842, and netstat confirms that the port is correct.

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• qTip pop ups come in from top left of screen (on first load)

  - by franko75

  Hi, not sure if i'm set things up incorrectly - I don't seem to see anyone else with this problem, but my qTip popups (all ajax loaded content) are loading quite erratically, in that they are often animating in from off screen before appearing in the correct position. Is there a simple solution to this which I may have missed? Thanks again for your help. HTML markup: <span class="formInfo"> <a href="http://localhost/httpdocs/index.php/help/kc_dob" class="jTip" name="" id="dob_help">?</a> </span> qTip initialisation.. //set up for qtip function initQtip() { $('a.jTip').each(function() { $(this).qtip( { content: { // Set the text to an image HTML string with the correct src URL to the loading image you want to use text: '<img src="/media/images/wait.gif" alt="Loading..." />', url: $(this).attr('href') // Use the rel attribute of each element for the url to load }, position: { adjust: { screen: true // Keep the tooltip on-screen at all times } }, show: { when: 'click', solo: true // Only show one tooltip at a time }, hide: 'unfocus', style: { tip: true, // Apply a speech bubble tip to the tooltip at the designated tooltip corner border: { width: 10, radius: 10 }, width: { min: 200, max: 500 }, name: 'light' // Use the default light style } }); //prevent default event on click }).bind('click', function(event){ event.preventDefault(); return false; }); }

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• Javascript and jQuery (Fancybox) question

  - by songdogtech

  Javascript and jQuery (Fancybox) question I'm using the Javascript function below for Twitter sharing (as well as other services; the function code is simplified to just Twitter for this question) that grabs the to-be-shared page URL and title and it is invoked in the link with onclick. That results in the Twitter share page loading in a pop up browser window, i.e.<img src="/images/twitter_16.png" onclick="share.tw()" /> In order to be consistent with other design aspects of the site, what I'd like to be able to do is have the Twitter share page open not in a standard browser window but in a Fancybox (jQuery) window. Fancybox can load an external page in an iFrame when the img or href link contains a class (in this case class="iframe" ) in the link and in the document ready function in the header. Right now, of course, when I give the iframe class to the link that also has the onclick share.tw(), I get two popups: one browser window popup with the correct Twitter share page loaded, and a Fancybox jQuery popup that shows a site 404. How can I change the function to use Fancybox to present the Twitter share page? Is that a correct way to approach it? Or is there a better way, such as implementing the share function in jQuery, too? Thanks... Javascript share function: var share = { tw:function(title,url) { this.share('http://twitter.com/home?status=##URL##+##TITLE##',title,url); }, share:function(tpl,title,url) { if(!url) url = encodeURIComponent(window.location); if(!title) title = encodeURIComponent(document.title); tpl = tpl.replace("##URL##",url); tpl = tpl.replace("##TITLE##",title); window.open(tpl,"sharewindow"+tpl.substr(6,15),"width=640,height=480"); } }; It is invoked, i.e.: <img src="/images/twitter_16.png" onclick="share.tw()" /> Fancybox function, invoked by adding class="iframe" in the img or href link $(".iframe").fancybox({ 'width' : '100%', 'height' : '100%', 'autoScale' : false, 'transitionIn' : 'none', 'transitionOut' : 'none', 'type' : 'iframe' });

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• Why is this Java Calendar comparison bad?

  - by joe7pak

  Hello folks. I'm having an inexplicable problem with the Java Calendar class when I'm trying to compare to dates. I'm trying to compare to Calendars and determine if their difference is than 1 day, and do things bases on that difference or not. But it doesn't work. If I do this with the two dates: String currDate = aCurrentUTCCalendar.getTime().toString(); String localDate = aLocalCalendar.getTime().toString(); I get these results: currDate = "Thu Jan 06 05:58:00 MST 2010" localDate = "Tue Jan 05 00:02:00 MST 2010" This is correct. But if I do this: long curr = aCurrentUTCCalendar.getTime().getTime(); long local = aLocalCalendar.getTime().getTime(); I get these results: ( in milliseconds since the epoch ) curr = -125566110120000 local = 1262674920000 Since there is only about a 30 hour different between the two, the magnitudes are vastly different, not to mention that annoying negative sign. This causes problems if I do this: long day = 60 * 60 * 24 * 1000; // 86400000 millis, one day if( local - curr > day ) { // do something } What's wrong? Why are the getTime().toString() calls correct, but the getTime().getTime() calls are vastly different? I'm using jdk 1.6_06 on WinXP. I can't upgrade the JDK for various reasons.

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• What applications is Python optimal for?

  - by Alan

  I'm already a professional J2EE developer by day, and Rails developer by night. I'm planning on adding Python to my list of skills. I'm already convinced a language is just a tool, so I'm not interested in a religious war. I agree with the Pragmatic Programmers that learning one language/year is a good thing for your professional development So, in your considered opinion, what kinds of applications does Python hit the sweet spot? And why? What advantages does it have, and why do these advantages outweigh the costs in adopting Python? ADD: I also plan on learning a pure functional language like Scheme.

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• Is it better to adopt the same technologies used at work to be effective on your home projects ?

  - by systempuntoout

  Is it better to start developing an home project using the same technologies used at work to be more productive and effective? I'm not talking about a simple hello world web page but an home project with all bells and whistles that one day, maybe, you could sell on internet. This dilemma is often subject of flames between me and a friend. He thinks that if you want to make a great home-made project you need to use the same technologies used daily at work staying in the same scope too; for example, a c++ computer game programmer should develope an home-made c++ game. I'm pretty sure that developing using the same technologies used at work can be more productive at beginning, but surely less exciting and stimulating of working with other languages\ides\libraries out of your daily job. What's your opinion about that?

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• Creating a web application that can be extended by plugins/modules

  - by Adam Pope

  I'm currently involved with developing a C# CMS-like web application which will be used to standardise our development of websites. From the outset, the idea has been to keep the core as simple as possible to avoid the complexity and menu/option overload that blights many CMS systems. This simple core is now complete and working very well. We envisisaged that the system would be able to accept plugins or modules which would extend the core functionality to suit a given projects needs. These would also be re-usable across projects. For example, a basic catalogue and shopping basket might be needed. All the code for such extensions should be in seperate assemblies. They should be able to provide their own admin interfaces and front-end code from this library. The system should search for available plugins and give the admin user the option to enable/disable the feature. (This is all very much like WordPress plugins) It is crucial that we attack this problem in the correct way, so I'm trying to perform as much due dilligence as possible before jumping in. I am aware of the Plugin Pattern (http://msdn.microsoft.com/en-us/library/ms972962.aspx) and have read some articles on it's use. It seems reasonable but I'm not convinced it's necessarily the correct/best technique for this situation. It seems more suited to processing applications (image/audio manipulation, maths etc). Are there any other options for achieving this kind of UI extensibility functionality? Or is the plugin pattern the way to go? I'd also be interested if anybody has links to articles that explain using the plugin pattern for this purpose?

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• Determine whether app is communicating with APNS sandbox or production environment

  - by goldierox

  I have push notifications set up in my app. I'm trying to determine whether the device token I've received from APNS in the application:didRegisterForRemoteNotificationsWithDeviceToken: method came from the sandbox or development environment. If I can distinguish which environment initialized the token, I'll be able to tell my server to which environment to send the push notification. I've tried using the DEBUG macro to determine this, but I've seen some strange behavior with this and don't trust it to be 100% correct. #ifdef DEBUG BOOL isProd = YES; #else BOOL isProd = NO; #endif Ideally, I'd be able to examine the aps-environment entitlement (value is Development or Production) in code, but I'm not sure if this is even possible. What's the proper way to determine whether your app is communicating with the APNS sandbox or production environments? I'm assuming that the server needs to know this in the first place. Please correct me if this is assumption is incorrect. Edited: Apple's documentation on Provider Communication with APNS details the difference between communicating with the sandbox and production. However, the documentation doesn't give information on how to be consistent with registering the token (from the iOS client app) and communicating with the server.

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• Are application servers necessary? Advantages of using one? (And other JEE questions)

  - by Mike

  Apologies for the long question.. there seems to be other similar questions on here but none really clear up my confusion. I'd be really grateful if someone could confirm or correct my understanding: Java Enterprise Edition is a set of APIs for building enterprise applications, which take away the burden of developing parts of the system that aren't actually features of the application you are trying to build (i.e. messaging, transactions etc). To do this, you can use an application server, which implements these APIs. So you could use JBoss, Glassfish, WebSphere, WebLogic etc which would provide your application with these enterprise services. However, there are many other implementations of these individual services available such as ActiveMQ for messaging, Hibernate for persistence, OpenEJB etc. You can download these implementations as Java libraries and include them in your application, and use the services they provide in a similar way to using the services provided by an application server. So if my understanding is correct, my questions are: I've read a lot of places that application servers are necessary for JEE features like EJB, but can't you just use an implementation such as OpenEJB and not need an application server at all? Are there any features that an application server provides which you cannot get from another source? Why would/wouldn't I choose an application server over a custom stack such as Tomcat, OpenEJB, ActiveMQ, and Hibernate? Is Spring a complete alternative to JEE? Does it ever require an application server or always just a servlet container? Why would someone choose Spring over JEE? Any help would be much appreciated!

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• javascript singleton question

  - by Shawn

  I just read a few threads on the discussion of singleton design in javascript. I'm 100% new to the Design Pattern stuff but as I see since a Singleton by definition won't have the need to be instantiated, conceptually if it's not to be instantiated, in my opinion it doesn't have to be treated like conventional objects which are created from a blueprint(classes). So my wonder is why not just think of a singleton just as something statically available that is wrapped in some sort of scope and that should be all. From the threads I saw, most of them make a singleton though traditional javascript new function(){} followed by making a pseudo constructor. Well I just think an object literal is enough enough: var singleton = { dothis: function(){}, dothat: function(){} } right? Or anybody got better insights? [update] : Again my point is why don't people just use a simpler way to make singletons in javascript as I showed in the second snippet, if there's an absolute reason please tell me. I'm usually afraid of this kind of situation that I simplify things to much :D

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• How can I find out how many rows of a matrix satisfy a rather complicated criterion (in R)?

  - by Brani

  As an example, here is a way to get a matrix of all possible outcomes of rolling 4 (fair) dice. z <- as.matrix(expand.grid(c(1:6),c(1:6),c(1:6),c(1:6))) As you may already have understood, I'm trying to work out a question that was closed, though, in my opinion, it's a challenging one. I used counting techniques to solve it (I mean by hand) and I finaly arrived to a number of outcomes, with a sum of subset being 5, equal to 1083 out of 1296. That result is consistent with the answers provided to that question, before it was closed. I was wondering how could that subset of outcomes (say z1, where dim(z1) = [1083,4] ) be generated using R. Do you have any ideas? Thank you.

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• different thread accessing MemoryStream

  - by Wayne

  There's a bit of code which writes data to a MemoryStream object directly into it's data buffer by calling GetBuffer(). It also uses and updates the Position and SetLength() properties appropriately. This code works purposes 99.9999% of the time. Literally. Only every so many 100,000's of iterations it will barf. The specific problem is that the memory.Position property suddenly returns zero instead of the appropriate value. However, code was added that checks for the 0 and throws an exception which include log of the MemoryStream properties like Position and Length in a separate method. Those return the correct value. Further addition shows that when this rare condition occurs, the memory.Position only has zero inside this particular method. Okay. Obviously, this must be a threading issue. But this code is well locked. However, the nature of this software is that it's organized by "tasks" with a scheduler and so any one of several actual O/S thread may run this code at any give time--but never more than one at a time. So it's my guess that ordinarily it so happens that the same thread keeps getting used for this method and then on a rare occasion a different thread get used. Then due to compiler optimizations, the different thread never gets the correct value. It gets a "stale" value. Ordinarily in a situation like this I would apply a "volatile" keyword to the variable in question. But that (those) variables are inside the MemoryStream object. Does anyone have any other idea? Or does this mean we have to implement our own MemoryStream object? (Just like we end up having to do with practically every collection in .NET?) It's a shame to have such an awesome platform as .NET and have virtually the entire system useless as-is for seriously parallelized applications. If I'm wrong or you have other ideas, please advise. Sincerely, Wayne

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• Is it Possible to Use Constraints on Hierarchical Data in a Self-Referential Table?

  - by pbarney

  Suppose you have the following table, intended to represent hierarchical data: +--------+-------------+ | Field | Type | +--------+-------------+ | id | int(10) | | parent | int(10) | | name | varchar(45) | +--------+-------------+ The table is self-referential in that the parent_id refers to id. So you might have the following data: +----+--------+---------------+ | id | parent | name | +----+--------+---------------+ | 1 | 0 | fruit | | 2 | 0 | vegetable | | 3 | 1 | apple | | 4 | 1 | orange | | 5 | 3 | red delicious | | 6 | 3 | granny smith | | 7 | 3 | gala | +----+--------+---------------+ Using MySQL, I am trying to impose a (self-referential) foreign key constraint upon the data to cascade on update and prevent deletion of a record if it has any "children." So I used the following: CREATE TABLE `test`.`fruit` ( `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `parent` INT(10) UNSIGNED, `name` VARCHAR(45) NOT NULL, PRIMARY KEY (`id`), CONSTRAINT `fk_parent` FOREIGN KEY (`parent`) REFERENCES `fruit` (`id`) ON UPDATE CASCADE ON DELETE RESTRICT ) ENGINE = InnoDB; From what I understand, this should fit my requirements. (And parent must default to null to allow insertions, correct?) The problem is, if I change the id of a record, it will not cascade: Cannot delete or update a parent row: a foreign key constraint fails (`test`.`fruit`, CONSTRAINT `fk_parent` FOREIGN KEY (`parent`) REFERENCES `fruit` (`id`) ON UPDATE CASCADE) What am I missing? Feel free to correct me if my terminology is screwed up... I'm new to constraints.

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• Optimization in Common Decalaration

  - by Pratik

  Its a 3-tier ASP.NET Website Project In Data Layer there is class "Common Decalaration" in which lot of common things are mentioned. Something this way : public class CommonDeclartion { #region Common Messages public const string RECORD_INSERT_MSG = "Record Inserted Successfully "; public const string RECORD_UPDATE_MSG = "Record Updated Successfully"; public const string RECORD_DELETE_MSG = "Record Deleted Successfully"; public const string ERROR_MSG = "Error Ocuured while Perfoming This Action."; public const string UserID_Incorrect = "Please Enter The Correct User ID."; public const string RECORD_ALREADY_EXIT = "Record Already Exit"; public const string NO_RECORD = "No Record found."; #endregion } Can this be more optimized in terms of : 1.Perfomance 2.Security(if any) 3.Code Readablity or Reusablity I thought of using enum but can't figure that out : enum CommonMessages { RECORD_INSERT_MSG "Record Inserted Successfully.", RECORD_UPDATE_MSG "Record Updated Successfully.", RECORD_DELETE_MSG "Record Deleted Successfully.", ERROR_MSG "Error Ocuured while Perfoming This Action.", UserID_Incorrect "Please Enter The Correct User ID.", RECORD_ALREADY_EXIT "Record Already Exit.", NO_RECORD "No Record found.", } or else should keep them in some collections like dictionary/NameValueCollection or so or i have to keep them in XML in form of key/value pair and reterive from it ? What can be better way keeping in mind 1.Perfomance 2.Security(if any) 3.Code Readablity or Reusablity

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