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  • Problem Binding a ObservableCollection to a ListBox in WPF/MVVM

    - by alexqs
    I'm working in some code , using wpf and starting to use mvvm. So far i have no problem, when i have one element and I have to show the values of it in the screen (binding of the specific name of the property). But now, i have to work with a property list , not knowing the names of it. So I created a class, named GClass, that only have two propierties, name and value. I created the ObservableCollection, and fill for now with direct values, and asign the view (lstview) datacontext with the object i have created. But I cant see any result, it always shows a blank listbox. Can someone tell me if see why is happening ? Code of c# VDt = new ObservableCollection<GClass>(); var vhDt = message.SelectSingleElement(typeof (Vh)) as Vehiculo; if(vhDt != null) { VDt.Add(new GClass() {Name = "Numero: ", Value = ""}); VDt.Add(new GClass() {Name = "Marca: ", Value = ""}); VDt.Add(new GClass() {Name = "Conductor: ", Value = ""}); lstview.DataContext = this; _regionManager.RegisterViewWithRegionInIndex(RegionNames.MainRegion, lstview, 0); Code of the view <ListBox Margin="5,5,5,25" ItemsSource="{Binding VDt}"> <ListBox.Template> <ControlTemplate> <ListViewItem Content="{Binding Name}"></ListViewItem> <ListViewItem Content="{Binding Value}"></ListViewItem> </ControlTemplate> </ListBox.Template> </ListBox> I have research here, but i cant see, what I'm doing wrong. I will apreciate if someone help me.

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  • Can I use a plaintext diff algorithm for tracking XML changes?

    - by rinogo
    Hi all! Interesting question for you here. I'm working in Flex/AS3 on (for simplicity) an XML editor. I need to provide undo/redo functionality. Of course, one solution is to store the entire source text with each edit. However, to conserve memory, I'd like to store the diffs instead (these diffs will also be used to transmit updates to the server for auto-saving). My question is - can I use a plaintext diff algorithm for tracking these XML changes? My research on the internet indicates that I cannot do so. However, I'm obviously missing something. Plaintext diff provides functionality that is purportedly: diff(text, text') - diffs patch(text, diffs) - text' XML is simply text, so why can't I just use diff() and patch() to transform the text reliably? For example: Let's say that I'm a poet. When I write poetry, I use lots of funky punctuation... You know, like <, /, and . (You might see where I'm going with this...) If I'm writing my poetry in an application that uses diffs to provide undo/redo functionality, does my poetry become garbled when I undo/redo my edits? It's just text! Why does it make a difference to the algorithm? I obviously don't get something here...Thanks for explaining! :) -Rich

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  • 2-step user registration with Django

    - by David S
    I'm creating a website with Django and want a fairly common 2-step user registration. What I mean by this is that the user fills in the some basic user information + some application specific information (sort of like a coupon value). Upon submit, an email is sent to ensure email address is valid. This email should contain a link to click on to "finish" the registration. When the link is clicked, the user is marked as validated and they are directed to a new page to complete optional "user profile" type information. So, pretty basic stuff. I have done some research and found django-registration by James Bennett. I do know who James is and have seen him at PyCons and DjanoCons in the past. There is obviously very few people in the world that know Django better than James (so, I know the quality of the code/app is good). But, it almost seems like a bit of over kill. I've read through the docs and was a bit confused (maybe I'm just being a bit dense today). I believe that if I do use django-registration, I will need to have some custom forms, etc. Is there anything else out there I should evaluate? Or are there any good tutorials or videos on using django-registration? I've done a bit of googling, but haven't found anything. But, I suspect that it might be a case of a lot of very common words that don't really find what you are looking for (django user registration tutorial/example). Or is just a case where it would be just about as easy to build your own solution with Django forms, etc? Here is the tech stack I'm using: Python 2.7.2 Django 1.3.1 PostgreSQL 9.1 psycopg2 2.4.1 Twitter Bootstrap 2.0.2

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  • ACL architechture for a Software As a service in Spring 3.0

    - by geoaxis
    I am making a software as a service using Spring 3.0 (Spring MVC, Spring Security, Spring Roo, Hibernate) I have to come up with a flexible access control list mechanism.I have three different kinds of users System (who can do any thing to the system, includes admin and internal daemons) Operations (who can add and delete users, organizations, and do maintenance work on behalf of users and organizations) End Users (they belong to one or more organization, for each organization, the user can have one or more roles, like being organization admin, or organization read-only member) (role like orgadmin can also add users for that organization) Now my question is, how should i model the entity of User? If I just take the End User, it can belong to one or more organizations, so each user can contain a set of references to its organizations. But how do we model the users role for each organization, So for example User UX belongs to organizations og1, og2 and og3, and for og1 he is both orgadmin, and org-read-only-user, where as for og2 he is only orgadmin and for og3 he is only org-read-only-user I have the possibility of making each user belong to one organization alone, but that's making the system bounded and I don't like that idea (although i would still satisfy the requirement) If you have a better extensible ACL architecture, please suggest it. Since its a software as a service, one would expect that alot of different organizations would be part if the same system. I had one concern that it is not a good idea to keep og1 and og2 data on the same DB (if og1 decides to spawn a 100 reports on the system, og2 should not suffer) But that is some thing advanced for now and is not directly related to ACL but to the physical distribution of data and setup of services based on those ACLs This is a community Wiki question, please correct any thing which you wish to do so. Thanks

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  • Bitwise Interval Arithmetic

    - by KennyTM
    I've recently read an interesting thread on the D newsgroup, which basically asks, Given two signed integers a ∈ [amin, amax], b ∈ [bmin, bmax], what is the tightest interval of a | b? I'm think if interval arithmetics can be applied on general bitwise operators (assuming infinite bits). The bitwise-NOT and shifts are trivial since they just corresponds to -1 − x and 2n x. But bitwise-AND/OR are a lot trickier, due to the mix of bitwise and arithmetic properties. Is there a polynomial-time algorithm to compute the intervals of bitwise-AND/OR? Note: Assume all bitwise operations run in linear time (of number of bits), and test/set a bit is constant time. The brute-force algorithm runs in exponential time. Because ~(a | b) = ~a & ~b and a ^ b = (a | b) & ~(a & b), solving the bitwise-AND and -NOT problem implies bitwise-OR and -XOR are done. Although the content of that thread suggests min{a | b} = max(amin, bmin), it is not the tightest bound. Just consider [2, 3] | [8, 9] = [10, 11].)

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  • UX question: is better to have "serious delete" or have "trash"

    - by ftrotter
    I am developing an application that allows for a user to manage some individual data points. One of the things that my users will want to do is "delete" but what should that mean? For a web application is it better to present a user with the option to have serious delete or to use a "trash" system? Under "serious delete" (would love to know if there is a better name for this...) you click "delete" and then the user is warned "this is final and tragic action. Once you do this you will not be able to get -insert data point name here- back, even if you are crying..." Then if they click delete... well it truly is gone forever. Under the "trash" model, you never trust that the user really wants to delete... instead you remove the data point from the "main display" and put into a bucket called "the trash". This gets it out of the users way, which is what they usually want, but they can get it back if they make a mistake. Obviously this is the way most operating systems have gone. The advantages of "serious delete" are: Easy to implement Easy to explain to users The disadvantages of "serious delete" are: it can be tragically final sometimes, cats walk on keyboards The advantages of the "trash" system are: user is safe from themselves bulk methods like "delete a bunch at once" make more sense saves support headaches The disadvantages of the "trash" system are": For sensitive data, you create an illusion of destruction users think something is gone, but it is not. Lots of subtle distinctions make implementation more difficult Do you "eventually" delete the contents of the trash? My question is which one is the right design pattern for modern web applications? With enough discussion to justify your answer... Would love to be pointed towards some relevant research. -FT

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  • Problems with zend-tool reporting that providers are not valid

    - by Mario
    I have recently setup XAMPP 1.7.3 and ZendFramework 1.10.4 on a new computer and many of the commands that I normally use now fail. Here are the steps I used to setup and test ZF. First I added the ZF library folder (C:\xampp\php\ZendFramework-1.10.4\library) to the include path in php.ini. Then I added the ZF bin folder (C:\xampp\php\ZendFramework-1.10.4\bin) to my Path system variable. To test that everything is configured correctly I ran the command "zf show version" from the command line. The result is "Zend Framework Version: 1.9.6". Immediately something appears to be wrong. The file that is downloaded is "ZendFramework-1.10.4.zip" and the reported version is 1.9.6. I have re-downloaded the latest version (1.10.4) and removed old copy. Still the incorrect version number problem persisted. Having done some research there is a bug in the ZF knowledgebase that version 1.10.3 reports a wrong version number. So that may explain the version number problem. Moving forward I tried to run some zf-tool commands and certain commands reports that the action or provider is not valid. Example: C:\xampp\htdocs>zf create project test Creating project at C:/xampp/htdocs/test C:\xampp\htdocs>cd test C:\xampp\htdocs\test>zf create controller Test Creating a controller at C:\xampp\htdocs\test/application/controllers/TestController.php ... Updating project profile 'C:\xampp\htdocs\test/.zfproject.xml' C:\xampp\htdocs\test>zf create action test Test Creating an action named test inside controller at C:\xampp\htdocs\test/application/controllers/TestController.php ... Updating project profile 'C:\xampp\htdocs\test/.zfproject.xml' C:\xampp\htdocs\test>zf enable layout An Error Has Occurred Action 'enable' is not a valid action. ... C:\xampp\htdocs\test>zf create form Test An Error Has Occurred Provider 'form' is not a valid provider. ... Can any one provide insight into these errors and how to correct them?

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  • Displaying ppt, doc, and xls in UIWebView doesn't work but pdf does

    - by slugolicious
    It looks like a few people on stackoverflow get this to work but their code isn't posted. I'm using [web loadData:data MIMEType:MIMEType textEncodingName:@"UTF-8" baseURL:nil]; where MIMEType is: @"application/vnd.ms-powerpoint" @"application/vnd.ms-word" @"application/vnd.ms-excel" (BTW, I've seen DOC files use mimetype @"application/msword" but the "vnd" version seems more appropriate. I tried both just in case.) I verified that my 'data' is correct. PDF and TXT files work. When the UIWebView displays PPT, DOC, or XLS files, it's blank. I put NSLOG statements in my UIWebViewDelegate calls. shouldStartLoadWithRequest:<NSMutableURLRequest about:blank> navType:5 webViewDidStartLoad: didFailLoadWithError:Error Domain=NSURLErrorDomain Code=100 UserInfo=0x122503a0 "Operation could not be completed. (NSURLErrorDomain error 100.)" didFailLoadWithError:Error Domain=WebKitErrorDomain Code=102 UserInfo=0x12253840 "Frame load interrupted" so obviously the load is failing, but why? If I change my mimetype to @"text/plain" for a PPT file, the UIWebView loads fine and displays unprintable characters, as expected. That's telling me the 'data' passed to loadData: is ok. Meaning my mimetypes are bad? And just to make sure my PPT, DOC, and XLS files are indeed ok to display, I created a simple html file with anchor tags to the files. When the html file is displayed in Safari on the iPhone, clicking on the files displays correctly in Safari. I tried to research the error code displayed in didFailLoadWithError (100) but all the documented error codes are negative and greater than 1000 (as seen in NSURLError.h). -(void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error { NSLog(@"didFailLoadWithError:%@", error); }

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  • Eclipse randomly exits after installation of Blackberry plugin/SDK

    - by canadiancreed
    Hello all Since adding the Blackberry Java classes from their website into eclipse, I've had it where eclipse will randomly close, with no discernible pattern, rhyme, error or reason. Here is the environment/software packages that I am using: Windows XP SP2 Eclipse v3.5.1 Blackberry Java Plugin v1.1.1.200911111641-15 Blackberry Java SDK 4.5.0.21 I've tried the usual steps of complete uninstall and reinstallation of Eclipse and the accompanying plugins on multiple systems with the same configuration, including one that had a fresh install of Windows XP SP2. Upgrading to Eclipse 3.6 didn't work (the plugin wont' install as it's the wrong version), nor the downgrade to 3.4 for the same reason. I also increased the heap size to 512 (system has two gigs of memory) as some research into Eclipse doing this type of thing with Groovy was resolved that way, but again, no dice. Eclipse works great when the blackberry plugins are not installed, and no entries of errors or issues in the event log are helping to show what the issue with these plug-ins might be. So if anyone has ran into this issue, and even better, has a solution, I'd love to hear about it. Thanks in advance. EDIT: An additional to my issue, autoComplete with the Blackberry SDK seems to make this extremely unstable, like almost a guaranteed crash. Is this fixable at all?

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  • Question about Multicast Delegates?

    - by IbrarMumtaz
    I am going through some exam questions for the 70-536 exam and an actual question one developer posted on his blog has popped up in my exam questions. I cannot remember what his answer was .... but below is the question: You need to write a multicast delegate that accepts a DateTime argument and returns a bool value. Which code segment should you use? A: public delegate int PowerDeviceOn(bool, DateTime) B: public delegate bool PowerDeviceOn(Object, EventArgs) C: public delegate void PowerDeviceOn(DateTime) D: public delegate bool PowerDeviceOn(DateTime) The answer is A. Can someone please explain why? As I already did some research into this question a while ago and so I was sure that it was C, obviously now looking back at the question its clear that I did not read properly. As i was sure I had seen the same one before so I jumped to the most obvious one. A variation on this question: You need to write a multicast delegate that accepts a DateTime argument. Which code segment should you use? A: public delegate int PowerDeviceOn(bool, DateTime) B: public delegate bool PowerDeviceOn(Object, EventArgs) C: public delegate void PowerDeviceOn(DateTime) D: public delegate bool PowerDeviceOn(DateTime) Now this is another variation on this question, it still has the same bogus sample answers, as they still kind work in throwing the exam taker off. Notice how by simply keeping the sample answers the same and by removing a small portion of the question text, the answer is C and not A. The variation has no official answer as I just conjured it up using the exam question as a baseplate. The answer is definitely C. This time round its easy to see why C is correct but the very first question I have an inkling but as you know an inkling is not good enough in passing exams. Thanks For Reading.

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  • nasm/yasm arguments, linkage to C++

    - by arionik
    Hello everybody, I've got a question concerning nasm and its linkage to C++. I declare a litte test function as extern "C" void __cdecl myTest( byte i1, byte i2, int stride, int *width ); and I call it like this: byte i1 = 1, i2 = 2; int stride = 3, width = 4; myTest( i1, i2, stride, &width ); the method only serves to debug assembly and have a look at how the stack pointer is used to get the arguments. beyond that, the pointer arguments value shall be set to 7, to figure out how that works. This is implemented like this: global _myTest _myTest: mov eax, [esp+4] ; 1 mov ebx, [esp+8] ; 2 mov ecx, dword [esp+16] ; width mov edx, dword [esp+12] ; stride mov eax, dword [esp+16] mov dword [eax], 7 ret and compiled via yasm -f win32 -g cv8 -m x86 -o "$(IntDir)\$(InputName).obj" "$(InputPath)" , then linked to the c++ app. In debug mode, everything works fine. the function is called a couple of times and works as expected, whereas in release mode the function works once, but subsequent programm operations fail. It seems to me that something's wrong with stack/frame pointers, near/far, but I'm quite new to this subject and need a little help. thanks in advance! a.

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  • Would OpenID or OAuth work for authorization/authentication on a distributed web service?

    - by David Eyk
    We're in the early stages of designing a RESTful/resource-oriented web service API for a computational lingustics application. Because many of the resources we plan to serve are rights-encumbered, a key design decision has been to specify the platform so that each resource provider can expose their own web service that complies with the API spec. This way, the rights owner maintains control over their content (and thus the ability to throttle or deny access at will) and a direct relationship with the consumer, while still being able to participate in in the collaborative network. At the same time, to simplify the job of writing a client for this service, we want to allow a client access to the distributed service through one end-point, with the server handling content negotiation and retrieval from the appropriate providers. Right now, we're at an impasse on authentication/authorization schemes. One of our number has argued for the (technical) simplicity of a central authentication registry, but others are concerned about the organizational complexity of such a scheme. It seems to me, based on an albeit limited understanding of the technologies, that a combination of OpenID and OAuth would do the trick, with a client authenticating with the end-point via OpenID, and the server taking action on the user's behalf with the various content providers using OAuth. I've only ever seen implementations (e.g. stackoverflow, twitter, etc.) where a human was present to intervene, and I still need to do more research on these technologies. Would a scheme like this work for an automated web service, or would it make the client too difficult to implement and operate?

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  • how to include .pl (PERL) file in PHP

    - by dexter
    i have two pages one in php(index.php) and another one in Perl(dbcon.pl). basically i want my php file to show only the UI and all the data operations would be done in Perl file. i have tried in index.pl <?php include("dbcon.pl");?> <html> <br/>PHP</br> </html> and dbcon.pl has #!/usr/bin/perl use strict; use warnings; use DBI; use CGI::Simple; my $cgi = CGI::Simple->new; my $dsn = sprintf('DBI:mysql:database=%s;host=%s','dbname','localhost'); my $dbh = DBI->connect($dsn,root =>'',{AutoCommit => 0,RaisError=> 0}); my $sql= "SELECT * FROM products"; my $sth =$dbh->prepare($sql); $sth->execute or die "SQL Error: $DBI::errstr\n"; while (my @row = $sth->fetchrow_array){ print $cgi->header, <<html; <div>&nbsp;@row[0]&nbsp;@row[1]&nbsp;@row[2]&nbsp;@row[3]&nbsp;@row[4]</div> html } but when i run index.php in browser it prints all the code in dbcon.pl file instead of executing it how to overcome this problem? note: i am running this in windows environment is there any other way to do this?

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  • Why isn’t my autoreleased object getting released?

    - by zoul
    Hello. I am debugging a weird memory management error and I can’t figure it out. I noticed that some of my objects are staying in memory longer than expected. I checked all my memory management and finally got to the very improbable conclusion that some of my autorelease operations don’t result in a release. Under what circumstances is that possible? I created a small testing Canary class that logs a message in dealloc and have the following testing code in place: NSLog(@"On the main thread: %i.", [NSThread isMainThread]); [[[Canary alloc] init] autorelease]; According to the code we’re really on the main thread, but the dealloc in Canary does not get called until much later. The delay is not deterministic and can easily take seconds or more. How is that possible? The application runs on a Mac, the garbage collection is turned off (Objective-C Garbage Collection is set to Unsupported on the target.) I am mostly used to iOS, is memory management on OS X different in some important way?

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  • CS Master's Degree Project vs. Thesis options

    - by Nwosh
    I'm doing a master's degree in computer science, and I'm currently at the point where I have to decide between the thesis and non-thesis options offered by my university. The thesis option was my first choice, it entails taking less courses but tends to take more time doing your thesis. The non-thesis option involves taking more coursework, taking a comprehensive exam, and doing a project in one semester with a faculty member. I'd like to pursue a PhD degree eventually (although not right away, I want to get some years of professional experience first), and I heard that having demonstrated the ability to work on a thesis helps a lot with admission (like: not doing thesis raises questions and suggests not being interested in research) and that the experience itself is very good. At the same time, almost everyone I know who did a thesis at my university took a long time (2-3 years), in theory it could be done in 1.5 years. I'm a part time student and I don't really want to spend so much time just getting a master's degree, I could still publish a few papers while working on the project option and I'd be done in a year or so, additionally, I heard having a master's degree with a project and more coursework is more desirable for the industry. So, when applying for a PhD degree in CS at some of the better universities, would the time spent working on the master's thesis help in getting me accepted? Or should I opt for the non-thesis option and hope that the extra coursework and publishing some papers would make up for not working on a thesis?

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  • What off-the-shelf licensing system will meet my needs?

    - by Anders Pedersen
    I'm looking for an off-the-shelf license system for desktop software. After some research on the net -- and of course here on StackOverflow -- I haven't found one the suits our needs. I have a couple of must-have features and some would-be-nice features: Must have: Encrypted unlock key Possibility to automate the unlock key generation on my website User info in key so that I can show name and company in an about box and perhaps in reports Nice to have: License managing tools Online activation Nice upgrade possibilities to a version with concurrent license model and subscription model I have looked at Manco, but I find them difficult to work with and the documentation is minimal. Further, I couldn't get the name in the key. Also, the automatic generation of a key on my website has to be done with an application web service, but I would rather program against a DLL. Next I looked at xheo. It is easier to use and the documentation is better, but the price is substantially higher and here you can only get the user name in the license file that you then have to provide together with the unlock key. Could anyone share their experiences on what you are using and how it is working for you?

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  • SQL Server 2005 database design - many-to-many relationships with hierarchy

    - by Remnant
    Note I have completely re-written my original post to better explain the issue I am trying to understand. I have tried to generalise the problem as much as possible. Also, my thanks to the original people who responded. Hopefully this post makes things a little clearer. Context In short, I am struggling to understand the best way to design a small scale database to handle (what I perceive to be) multiple many-to-many relationships. Imagine the following scenario for a company organisational structure: Textile Division Marketing Division | | ---------------------- ---------------------- | | | | HR Dept Finance Dept HR Dept Finance Dept | | | | ---------- ---------- ---------- --------- | | | | | | | | Payroll Hiring Audit Tax Payroll Hiring Audit Accounts | | | | | | | | Emps Emps Emps Emps Emps Emps Emps Emps NB: Emps denotes a list of employess that work in that area When I first started with this issue I made four separate tables: Divisions - Textile, Marketing (PK = DivisionID) Departments - HR, Finance (PK = DeptID) Functions - Payroll, Hiring, Audit, Tax, Accounts (PK = FunctionID) Employees - List of all Employees (PK = EmployeeID) The problem as I see it is that there are multiple many-to-many relationships i.e. many departments have many divisions and many functions have many departments. Question Giving the database structure above, suppose I wanted to do the following: Get all employees who work in the Payroll function of the Marketing Division To do this I need to be able to differentiate between the two Payroll departments but I am not sure how this can be done? I understand that I could build a 'Link / Junction' table between Departments and Functions so that I can retrieve which Functions are in which Departments. However, I would still need to differentiate the Division they belong to. Research Effort As you can see I am an abecedarian when it comes to database deisgn. I have spent the last two days resaerching this issue, traversing nested set models, adjacency models, reading that this issue is known not to be NP complete etc. I am sure there is a simple solution?

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  • What is your best-practice advice on implementing SQL stored procedures (in a C# winforms applicatio

    - by JYelton
    I have read these very good questions on SO about SQL stored procedures: When should you use stored procedures? and Are Stored Procedures more efficient, in general, than inline statements on modern RDBMS’s? I am a beginner on integrating .NET/SQL though I have used basic SQL functionality for more than a decade in other environments. It's time to advance with regards to organization and deployment. I am using .NET C# 3.5, Visual Studio 2008 and SQL Server 2008; though this question can be regarded as language- and database- agnostic, meaning that it could easily apply to other environments that use stored procedures and a relational database. Given that I have an application with inline SQL queries, and I am interested in converting to stored procedures for organizational and performance purposes, what are your recommendations for doing so? Here are some additional questions in my mind related to this subject that may help shape the answers: Should I create the stored procedures in SQL using SQL Management Studio and simply re-create the database when it is installed for a client? Am I better off creating all of the stored procedures in my application, inside of a database initialization method? It seems logical to assume that creating stored procedures must follow the creation of tables in a new installation. My database initialization method creates new tables and inserts some default data. My plan is to create stored procedures following that step, but I am beginning to think there might be a better way to set up a database from scratch (such as in the installer of the program). Thoughts on this are appreciated. I have a variety of queries throughout the application. Some queries are incredibly simple (SELECT id FROM table) and others are extremely long and complex, performing several joins and accepting approximately 80 parameters. Should I replace all queries with stored procedures, or only those that might benefit from doing so? Finally, as this topic obviously requires some research and education, can you recommend an article, book, or tutorial that covers the nuances of using stored procedures instead of direct statements?

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  • Scalable / Parallel Large Graph Analysis Library?

    - by Joel Hoff
    I am looking for good recommendations for scalable and/or parallel large graph analysis libraries in various languages. The problems I am working on involve significant computational analysis of graphs/networks with 1-100 million nodes and 10 million to 1+ billion edges. The largest SMP computer I am using has 256 GB memory, but I also have access to an HPC cluster with 1000 cores, 2 TB aggregate memory, and MPI for communication. I am primarily looking for scalable, high-performance graph libraries that could be used in either single or multi-threaded scenarios, but parallel analysis libraries based on MPI or a similar protocol for communication and/or distributed memory are also of interest for high-end problems. Target programming languages include C++, C, Java, and Python. My research to-date has come up with the following possible solutions for these languages: C++ -- The most viable solutions appear to be the Boost Graph Library and Parallel Boost Graph Library. I have looked briefly at MTGL, but it is currently slanted more toward massively multithreaded hardware architectures like the Cray XMT. C - igraph and SNAP (Small-world Network Analysis and Partitioning); latter uses OpenMP for parallelism on SMP systems. Java - I have found no parallel libraries here yet, but JGraphT and perhaps JUNG are leading contenders in the non-parallel space. Python - igraph and NetworkX look like the most solid options, though neither is parallel. There used to be Python bindings for BGL, but these are now unsupported; last release in 2005 looks stale now. Other topics here on SO that I've looked at have discussed graph libraries in C++, Java, Python, and other languages. However, none of these topics focused significantly on scalability. Does anyone have recommendations they can offer based on experience with any of the above or other library packages when applied to large graph analysis problems? Performance, scalability, and code stability/maturity are my primary concerns. Most of the specialized algorithms will be developed by my team with the exception of any graph-oriented parallel communication or distributed memory frameworks (where the graph state is distributed across a cluster).

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  • JAXB, BigDecimal or double?

    - by Alex
    I working on different web-services, and I always use WSDL First. JAXB generates for a Type like: <xsd:simpleType name="CurrencyFormatTyp"> <xsd:restriction base="xsd:decimal"> <xsd:totalDigits value="13"/> <xsd:fractionDigits value="2"/> <xsd:minInclusive value="0.01"/> </xsd:restriction> </xsd:simpleType> a Java binding type BigDecimal (as it's mentioned in JAXB specification). When I then do some simple arithmetic operation with values of the type double (which are stored in a database and mapped via hibernate to the type double) I run into trouble. <ns5:charge>0.200000000000000011102230246251565404236316680908203125</ns5:charge> <ns5:addcharge>0.0360000000000000042188474935755948536098003387451171875</ns5:addcharge> <ns5:tax>0.047199999999999998900879205621095024980604648590087890625</ns5:tax> <ns5:totalextax>0.2360000000000000153210777398271602578461170196533203125</ns5:totalextax> What would be the right way? Convert all my values into double (JAXB binding from BigDecimal to double) Hibernate mapping double to Bigdecimal and do all my arithmetic operations in one object type.

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  • Browser Based Streaming Video/Audio (not progressive download)

    - by Josh
    Hello, I am trying to understand conceptually the best way to deliver real streaming audio and video content. I would want it to be consumed with a web browser, utilizing the least amount of proprietary technology. I wouldn't be serving static files and using progressive download, this would be real audio streams being captured live. How does one broadcast a stream that will be reasonably in sync with the source? What kind of protocol is suitable? Edit: In research I've found that there are a few protocols: RTSP, HTTP Streaming, RTMP, and RTP. HTTP streaming is somewhat unsuitable if you are streaming a live performance/communication of some kind because it relies on TCP (as its HTTP based) and you don't lose packets. In a low bandwidth situation, the client can get significantly behind in playback. ref RTMP is a proprietary technology, requiring flash media server. Crap on that. The reason I looked at flash is because they are extremely flexible as far as user experience goes. SoundManager2 provides an excellent javascript interface for playing media with flash. This is what I would look for in a client application. RTSP/RTP is what Microsoft switched to using, deprecating their MMS protocol. RTSP is the control protocol. Its similar to HTTP with a few distinct difference -- server can also talk to the client, and there are additional commands, like PAUSE. Its also a stateful protocol, which is maintained with a session id. RTP is the protocol for delivering the payload (encoded audio or video). There are a few open sourced projects, one of them being supported by apple here. It seems like this might do what I want it to, and it looks like quite a few players support it. It sounds like it would be suitable for a "live" broadcast from this page here. Thanks, Josh

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  • Can a WCF Service provide publish/subscribe activity to a Linux-based C++ client application?

    - by Jeremy Roddingham
    I have a WCF service written to provide certain functionality to intranet-based clients. This is easy when a client is running Windows. I want to implement the same functionality for my Windows clients that is available to my linux clients. My questions are? How can I communicate to a linux c++ based client (supporting callback operations for a publish subscribe) type situation? I am aware of using SOAP over the HTTPBinding but is that the only way (does not support callbacks I believe)? Would the same apply if I were using TCPBinding on the service-side? Currently, the service is set up using TCP but what are my options for the linux client communcation? I read somewhere that messages can also be sent (via webservices I believe) in XML rather than SOAP? Which would be a better approach or how to determine which is a better approach? I am trying to understand the options I would have for a WCF data service if I wanted to communicate with it from a linux client. I appreciate all your help. Thank You, Jeremy

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  • Will fixed-point arithmetic be worth my trouble?

    - by Thomas
    I'm working on a fluid dynamics Navier-Stokes solver that should run in real time. Hence, performance is important. Right now, I'm looking at a number of tight loops that each account for a significant fraction of the execution time: there is no single bottleneck. Most of these loops do some floating-point arithmetic, but there's a lot of branching in between. The floating-point operations are mostly limited to additions, subtractions, multiplications, divisions and comparisons. All this is done using 32-bit floats. My target platform is x86 with at least SSE1 instructions. (I've verified in the assembler output that the compiler indeed generates SSE instructions.) Most of the floating-point values that I'm working with have a reasonably small upper bound, and precision for near-zero values isn't very important. So the thought occurred to me: maybe switching to fixed-point arithmetic could speed things up? I know the only way to be really sure is to measure it, that might take days, so I'd like to know the odds of success beforehand. Fixed-point was all the rage back in the days of Doom, but I'm not sure where it stands anno 2010. Considering how much silicon is nowadays pumped into floating-point performance, is there a chance that fixed-point arithmetic will still give me a significant speed boost? Does anyone have any real-world experience that may apply to my situation?

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  • Timeout reading verity collection - CF8

    - by Gary
    For a long time now I've been having a problem with using the verity search service bundled with ColdFusion 8. The issue is with timeout errors occurring when perfoming any operation on a collection. It's intermittent, and usually occurs after a few operations have been successfully performed. For instance: If I'm adding records to a collection the first, say 15 records, will go through with no problems, but all subsequent records will timeout until the service is rebooted. I'm on a shared server, Windows 2008, 64bit as far as I know. The error I receive is: "An error occurred while performing an operation in the Search Engine library. Error reading collection information.: com.verity.api.administration.ConfigurationException: java.io.IOException: Read timed out" Having spoken to my hosting company, and after doing some research, it's been suggested that the number of collections on a server may cause this issue. I've reduced the amount of collections I use, and there are currently 39 collections on the server. As I'm on a shared server, I have no control over how many collections other customers use, however I've read that the limit is 128 collections, so I don't see why 39 should cause it to become unusable. The collections aren't big, there's maybe around 5,000 records between all of them. Any ideas?

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  • Login to website using PHP and get text from page

    - by Anthony Garand
    I am trying to login to a website and grab content from a page you must be authenticated to see. I have done some research and have seen some examples using both cURL and stream_context_create but I cannot get either way to work. I have the url for the page to login to, and the page that contains the data I need to get. Your help is much appreciated! Here's what I'm working with: <?php $pages = array('home' => 'https://www.53.com/wps/portal/personal', 'login' => 'https://www.53.com/wps/portal/personal', 'data' => 'https://www.53.com/servlet/efsonline/index.html?Messages.SortedBy=DATE,REVERSE'); $ch = curl_init(); //Set options for curl session $options = array(CURLOPT_USERAGENT => 'Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0)', CURLOPT_SSL_VERIFYPEER => FALSE, CURLOPT_SSL_VERIFYHOST => 2, CURLOPT_HEADER => TRUE, //CURLOPT_RETURNTRANSFER => TRUE, CURLOPT_COOKIEFILE => 'cookie.txt', CURLOPT_COOKIEJAR => 'cookies.txt'); //Hit home page for session cookie $options[CURLOPT_URL] = $pages['home']; curl_setopt_array($ch, $options); curl_exec($ch); //Login $options[CURLOPT_URL] = $pages['login']; $options[CURLOPT_POST] = TRUE; $options[CURLOPT_POSTFIELDS] = 'uid-input=xxx&pw=xxx'; $options[CURLOPT_FOLLOWLOCATION] = FALSE; curl_setopt_array($ch, $options); curl_exec($ch); //Hit data page $options[CURLOPT_URL] = $pages['data']; curl_setopt_array($ch, $options); $data = curl_exec($ch); //Output data echo $data; //Close curl session curl_close($ch); ?> Cheers, Anthony

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