Search Results

Search found 10556 results on 423 pages for 'practical approach'.

Page 396/423 | < Previous Page | 392 393 394 395 396 397 398 399 400 401 402 403  | Next Page >

• Advice on software / database design to avoid using cursors when updating database

  - by Remnant

  I have a database that logs when an employee has attended a course and when they are next due to attend the course (courses tend to be annual). As an example, the following employee attended course '1' on 1st Jan 2010 and, as the course is annual, is due to attend next on the 1st Jan 2011. As today is 20th May 2010 the course status reads as 'Complete' i.e. they have done the course and do not need to do it again until next year: EmployeeID CourseID AttendanceDate DueDate Status 123456 1 01/01/2010 01/01/2011 Complete In terms of the DueDate I calculate this in SQL when I update the employee's record e.g. DueDate = AttendanceDate + CourseFrequency (I pull course frequency this from a separate table). In my web based app (asp.net mvc) I pull back this data for all employees and display it in a grid like format for HR managers to review. This allows HR to work out who needs to go on courses. The issue I have is as follows. Taking the example above, suppose today is 2nd Jan 2011. In this case, employee 123456 is now overdue for the course and I would like to set the Status to Incomplete so that the HR manager can see that they need to action this i.e. get employee on the course. I could build a trigger in the database to run overnight to update the Status field for all employees based on the current date. From what I have read I would need to use cursors to loop over each row to amend the status and this is considered bad practice / inefficient or at least something to avoid if you can??? Alternatively, I could compute the Status in my C# code after I have pulled back the data from the database and before I display it on screen. The issue with this is that the Status in the database would not necessarily match what is shown on screen which just feels plain wrong to me. Does anybody have any advice on the best practice approach to such an issue? It helps, if I did use a cursor I doubt I would be looping over more than 1000 records at any given time. Maybe this is such small volume that using cursors is okay?

  Read the article

• ELMAH - Using custom error pages to collecting user feedback

  - by vdh_ant

  Hey guys I'm looking at using ELMAH for the first time but have a requirement that needs to be met that I'm not sure how to go about achieving... Basically, I am going to configure ELMAH to work under asp.net MVC and get it to log errors to the database when they occur. On top of this I be using customErrors to direct the user to a friendly message page when an error occurs. Fairly standard stuff... The requirement is that on this custom error page I have a form which enables to user to provide extra information if they wish. Now the problem arises due to the fact that at this point the error is already logged and I need to associate the loged error with the users feedback. Normally, if I was using my own custom implementation, after I log the error I would pass through the ID of the error to the custom error page so that an association can be made. But because of the way that ELMAH works, I don't think the same is quite possible. Hence I was wondering how people thought that one might go about doing this.... Cheers UPDATE: My solution to the problem is as follows: public class UserCurrentConextUsingWebContext : IUserCurrentConext { private const string _StoredExceptionName = "System.StoredException."; private const string _StoredExceptionIdName = "System.StoredExceptionId."; public virtual string UniqueAddress { get { return HttpContext.Current.Request.UserHostAddress; } } public Exception StoredException { get { return HttpContext.Current.Application[_StoredExceptionName + this.UniqueAddress] as Exception; } set { HttpContext.Current.Application[_StoredExceptionName + this.UniqueAddress] = value; } } public string StoredExceptionId { get { return HttpContext.Current.Application[_StoredExceptionIdName + this.UniqueAddress] as string; } set { HttpContext.Current.Application[_StoredExceptionIdName + this.UniqueAddress] = value; } } } Then when the error occurs, I have something like this in my Global.asax: public void ErrorLog_Logged(object sender, ErrorLoggedEventArgs args) { var item = new UserCurrentConextUsingWebContext(); item.StoredException = args.Entry.Error.Exception; item.StoredExceptionId = args.Entry.Id; } Then where ever you are later you can pull out the details by var item = new UserCurrentConextUsingWebContext(); var error = item.StoredException; var errorId = item.StoredExceptionId; item.StoredException = null; item.StoredExceptionId = null; Note this isn't 100% perfect as its possible for the same IP to have multiple requests to have errors at the same time. But the likely hood of that happening is remote. And this solution is independent of the session, which in our case is important, also some errors can cause sessions to be terminated, etc. Hence why this approach has worked nicely for us.

  Read the article

• ASP.NET MVC Custom Error Pages with Magical Unicorn

  - by FLClover

  my question is regarding Pure.Kromes answer to this post. I tried implementing my pages' custom error messages using his method, yet there are some problems I can't quite explain. a) When I provoke a 404 Error by entering in invalid URL such as localhost:3001/NonexistantPage, it defaults to the ServerError() Action of my error controller even though it should go to NotFound(). Here is my ErrorController: public class ErrorController : Controller { public ActionResult NotFound() { Response.TrySkipIisCustomErrors = true; Response.StatusCode = (int)HttpStatusCode.NotFound; var viewModel = new ErrorViewModel() { ServerException = Server.GetLastError(), HTTPStatusCode = Response.StatusCode }; return View(viewModel); } public ActionResult ServerError() { Response.TrySkipIisCustomErrors = true; Response.StatusCode = (int)HttpStatusCode.InternalServerError; var viewModel = new ErrorViewModel() { ServerException = Server.GetLastError(), HTTPStatusCode = Response.StatusCode }; return View(viewModel); } } My error routes in Global.asax.cs: routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.IgnoreRoute("{*favicon}", new { favicon = @"(.*/)?favicon.ico(/.*)?" }); routes.MapRoute( name: "Error - 404", url: "NotFound", defaults: new { controller = "Error", action = "NotFound" } ); routes.MapRoute( name: "Error - 500", url: "ServerError", defaults: new { controller = "Error", action = "ServerError" } ); And my web.config settings: <system.web> <customErrors mode="On" redirectMode="ResponseRewrite" defaultRedirect="/ServerError"> <error statusCode="404" redirect="/NotFound" /> </customErrors> ... </system.web> <system.webServer> <httpErrors errorMode="Custom" existingResponse="Replace"> <remove statusCode="404" subStatusCode="-1" /> <error statusCode="404" path="/NotFound" responseMode="ExecuteURL" /> <remove statusCode="500" subStatusCode="-1" /> <error statusCode="500" path="/ServerError" responseMode="ExecuteURL" /> </httpErrors> ... The Error views are located in /Views/Error/ as NotFound.cshtml and ServerError.cshtml. b) One funny thing is, When a server error occurs, it does in fact display the Server Error view I defined, however it also outputs a default error message as well saying that the Error page could not be found. Here's how it looks like: Do you have any advice how I could fix these two problems? I really like Pure.Kromes approach to implementing these error messages, but if there are better ways of achieving this don't hestitate to tell me. Thanks! *EDIT : * I can directly navigate to my views through the ErrorController by accessing /Error/NotFound or Error/ServerError. The views themselves only contain some text, no markup or anything. As I said, it actually works in some way, just not the way I intended it to work. There seems to be an issue with the redirect in the web.config, but I haven't been able to figure it out.

  Read the article

• How best to store Subversion version information in EAR's?

  - by Rene

  When receiving a bug report or an it-doesnt-work message one of my initials questions is always what version? With a different builds being at many stages of testing, planning and deploying this is often a non-trivial question. I the case of releasing Java JAR (ear, jar, rar, war) files I would like to be able to look in/at the JAR and switch to the same branch, version or tag that was the source of the released JAR. How can I best adjust the ant build process so that the version information in the svn checkout remains in the created build? I was thinking along the lines of: adding a VERSION file, but with what content? storing information in the META-INF file, but under what property with which content? copying sources into the result archive added svn:properties to all sources with keywords in places the compiler leaves them be I ended up using the svnversion approach (the accepted anwser), because it scans the entire subtree as opposed to svn info which just looks at the current file / directory. For this I defined the SVN task in the ant file to make it more portable. <taskdef name="svn" classname="org.tigris.subversion.svnant.SvnTask"> <classpath> <pathelement location="${dir.lib}/ant/svnant.jar"/> <pathelement location="${dir.lib}/ant/svnClientAdapter.jar"/> <pathelement location="${dir.lib}/ant/svnkit.jar"/> <pathelement location="${dir.lib}/ant/svnjavahl.jar"/> </classpath> </taskdef> Not all builds result in webservices. The ear file before deployment must remain the same name because of updating in the application server. Making the file executable is still an option, but until then I just include a version information file. <target name="version"> <svn><wcVersion path="${dir.source}"/></svn> <echo file="${dir.build}/VERSION">${revision.range}</echo> </target> Refs: svnrevision: http://svnbook.red-bean.com/en/1.1/re57.html svn info http://svnbook.red-bean.com/en/1.1/re13.html subclipse svn task: http://subclipse.tigris.org/svnant/svn.html svn client: http://svnkit.com/

  Read the article

• Delaying emails in PHP to avoid exceeding server limit

  - by Andrew P.

  Okay, so here's my problem: I have a list of members on a website, and periodically one of the admins my site (who are not very web or tech savvy) will send a newsletter to the memberlist. My current memberlist is well over 800 individuals long. So, I wrote an email script that sends the email to the full memberlist, with the members listed in the Bcc header. However, I've discovered that my host server has a limit of 300 emails per hour, which I apparently exceed even though the members are listed in the Bcc field. (I wasn't previously aware that the behaviour of Bcc was to send separate emails for each name on the list...) After some thought, I've come to the conclusion that my only solution is to have my script send only the email to only the first 300 emails, wait an hour, and send a second email to the next three hundred, wait another hour, and so on until I've sent the email to the whole member list. Looking around on the internet, I've seen some other solutions people have come up with for delaying emails in PHP. Sleep() is obviously not an option, because I can't just leave the script open and running for 3 or four hours. I've seen some people suggest cron jobs, but I'm not sure how feasible it would be to create three new cron jobs every time I send an email, use them once, and then delete them afterward. The final (and what I think is the smartest) solution I've seen, is to have a table in my database to temporarily store the emails to be delayed and sent later, and then create a cron job that checks this sql table every hour or so, compares the timestamp of the row to the current timestamp, and then sends the email if an hour has passed. So I'm asking you all which method you would recommend. Is there an easier solution that I've completely looked over (aside from getting a different hosting plan. ha!), or is there a cleaner way to do it than the database / cron job approach? tl;dr: I have 800 emails to send in an hour on a server that limits me to 300/hr. Using PHP, find a way to get around this problem in a way that the person sending the email needs only to click "send."

  Read the article

• subclassing QList and operator+ overloading

  - by Milen

  I would like to be able to add two QList objects. For example: QList<int> b; b.append(10); b.append(20); b.append(30); QList<int> c; c.append(1); c.append(2); c.append(3); QList<int> d; d = b + c; For this reason, I decided to subclass the QList and to overload the operator+. Here is my code: class List : public QList<int> { public: List() : QList<int>() {} // Add QList + QList friend List operator+(const List& a1, const List& a2); }; List operator+(const List& a1, const List& a2) { List myList; myList.append(a1[0] + a2[0]); myList.append(a1[1] + a2[1]); myList.append(a1[2] + a2[2]); return myList; } int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); List b; b.append(10); b.append(20); b.append(30); List c; c.append(1); c.append(2); c.append(3); List d; d = b + c; List::iterator i; for(i = d.begin(); i != d.end(); ++i) qDebug() << *i; return a.exec(); } , the result is correct but I am not sure whether this is a good approach. I would like to ask whether there is better solution?

  Read the article

• Buy or Build for web deployment?

  - by Cannonade

  I have been evaluating the wide range of installation and web deployment solutions available for Windows applications. I will just clarify here (without too much detail, these tools have been covered in other questions) my understanding of the options: NSIS - Free tool that generates setup executables. Small binary. Specialized, sometimes obtuse, scripting language. Inno Setup - Free tools for setup executables. Various binary compression schemes. Pascal scripting engine. WIX - Free toolset to generate MSI binaries. XML definitions language. WIX ClickThrough - Additional tools for packaging, web download and auto update detection (now part of WIX core). InstallShield - Commercial development environment for installation packaging. Generates MSI binaries. C-like InstallScript language. Wise - Commercial development environment for installation packaging. Generates MSI binaries. ClickOnce - Visual Studio supported framework for publishing applications to a webserver, with automatic detection of updates. No support for custom installation requirements (INI files, registry etc ...). Packages setup as an MSI binary. Install Aware - Commercial development environment for installation. Generates MSI binaries. Automatic Update framwork (Web Update). If I have missed any, please let me know. And found some useful discussions of these technologies on StackOverflow: Best Simple Install System Best choice for Windows installers Alternatives to ClickOnce I have worked with a few of these solutions, as well as a handful of proprietary internal installation solutions. They are mostly concerned with packing installations and providing a framework for developers to access the run time environment. With the growing requirement for web deployment and automatic software updates, I expected to find more of a consensus among developers on a framework for web delivery of software and subsequent updates, I haven't really found that consensus. There are certainly solutions available (ClickOnce, ClickThrough, InstallShield Update Service), but they each have considerable limitations (please correct me if I mis-represent any of these). I would be interested in a framework that provided some of the following: Third party hosting/management of updates. Access to client environment (INI files, registry, etc..). User registration/activation. Feedback/Error reporting This is leaving me with the strong impression that the best way to approach the web deployment problem is through a custom built proprietary solution (possibly leveraging existing installer packaging). I have seen this sort of solution work well for a number of successful applications: FileZilla - HTTP request to update.filezilla-project.org to check for updates, downloads an NSIS binary (I think) and then shuts down to run the install.

  Read the article

• Calling/selecting variables (float valued) with user input in Python

  - by Jonathan Straus

  I've been working on a computational physics project (plotting related rates of chemical reactants with respect to eachother to show oscillatory behavior) with a fair amount of success. However, one of my simulations involves more than two active oscillating agents (five, in fact) which would obviously be unsuitable for any single visual plot... My scheme was hence to have the user select which two reactants they wanted plotted on the x-axis and y-axis respectively. I tried (foolishly) to convert string input values into the respective variable names, but I guess I need a radically different approach if any exist? If it helps clarify any, here is part of my code: def coupledBrusselator(A, B, t_trial,display_x,display_y): t = 0 t_step = .01 X = 0 Y = 0 E = 0 U = 0 V = 0 dX = (A) - (B+1)*(X) + (X**2)*(Y) dY = (B)*(X) - (X**2)*(Y) dE = -(E)*(U) - (X) dU = (U**2)*(V) -(E+1)*(U) - (B)*(X) dV = (E)*(U) - (U**2)*(V) array_t = [0] array_X = [0] array_Y = [0] array_U = [0] array_V = [0] while t <= t_trial: X_1 = X + (dX)*(t_step/2) Y_1 = Y + (dY)*(t_step/2) E_1 = E + (dE)*(t_step/2) U_1 = U + (dU)*(t_step/2) V_1 = V + (dV)*(t_step/2) dX_1 = (A) - (B+1)*(X_1) + (X_1**2)*(Y_1) dY_1 = (B)*(X_1) - (X_1**2)*(Y_1) dE_1 = -(E_1)*(U_1) - (X_1) dU_1 = (U_1**2)*(V_1) -(E_1+1)*(U_1) - (B)*(X_1) dV_1 = (E_1)*(U_1) - (U_1**2)*(V_1) X_2 = X + (dX_1)*(t_step/2) Y_2 = Y + (dY_1)*(t_step/2) E_2 = E + (dE_1)*(t_step/2) U_2 = U + (dU_1)*(t_step/2) V_2 = V + (dV_1)*(t_step/2) dX_2 = (A) - (B+1)*(X_2) + (X_2**2)*(Y_2) dY_2 = (B)*(X_2) - (X_2**2)*(Y_2) dE_2 = -(E_2)*(U_2) - (X_2) dU_2 = (U_2**2)*(V_2) -(E_2+1)*(U_2) - (B)*(X_2) dV_2 = (E_2)*(U_2) - (U_2**2)*(V_2) X_3 = X + (dX_2)*(t_step) Y_3 = Y + (dY_2)*(t_step) E_3 = E + (dE_2)*(t_step) U_3 = U + (dU_2)*(t_step) V_3 = V + (dV_2)*(t_step) dX_3 = (A) - (B+1)*(X_3) + (X_3**2)*(Y_3) dY_3 = (B)*(X_3) - (X_3**2)*(Y_3) dE_3 = -(E_3)*(U_3) - (X_3) dU_3 = (U_3**2)*(V_3) -(E_3+1)*(U_3) - (B)*(X_3) dV_3 = (E_3)*(U_3) - (U_3**2)*(V_3) X = X + ((dX + 2*dX_1 + 2*dX_2 + dX_3)/6) * t_step Y = Y + ((dX + 2*dY_1 + 2*dY_2 + dY_3)/6) * t_step E = E + ((dE + 2*dE_1 + 2*dE_2 + dE_3)/6) * t_step U = U + ((dU + 2*dU_1 + 2*dY_2 + dE_3)/6) * t_step V = V + ((dV + 2*dV_1 + 2*dV_2 + dE_3)/6) * t_step dX = (A) - (B+1)*(X) + (X**2)*(Y) dY = (B)*(X) - (X**2)*(Y) t_step = .01 / (1 + dX**2 + dY**2) ** .5 t = t + t_step array_X.append(X) array_Y.append(Y) array_E.append(E) array_U.append(U) array_V.append(V) array_t.append(t) where previously display_x = raw_input("Choose catalyst you wish to analyze in the phase/field diagrams (X, Y, E, U, or V) ") display_y = raw_input("Choose one other catalyst from list you wish to include in phase/field diagrams ") coupledBrusselator(A, B, t_trial, display_x, display_y) Thanks!

  Read the article

• Silverlight with MVVM Inheritance: ModelView and View matching the Model

  - by moonground.de

  Hello Stackoverflowers! :) Today I have a special question on Silverlight (4 RC) MVVM and inheritance concepts and looking for a best practice solution... I think that i understand the basic idea and concepts behind MVVM. My Model doesn't know anything about the ViewModel as the ViewModel itself doesn't know about the View. The ViewModel knows the Model and the Views know the ViewModels. Imagine the following basic (example) scenario (I'm trying to keep anything short and simple): My Model contains a ProductBase class with a few basic properties, a SimpleProduct : ProductBase adding a few more Properties and ExtendedProduct : ProductBase adding another properties. According to this Model I have several ViewModels, most essential SimpleProductViewModel : ViewModelBase and ExtendedProductViewModel : ViewModelBase. Last but not least, according Views SimpleProductView and ExtendedProductView. In future, I might add many product types (and matching Views + VMs). 1. How do i know which ViewModel to create when receiving a Model collection? After calling my data provider method, it will finally end up having a List<ProductBase>. It containts, for example, one SimpleProduct and two ExtendedProducts. How can I transform the results to an ObservableCollection<ViewModelBase> having the proper ViewModel types (one SimpleProductViewModel and two ExtendedProductViewModels) in it? I might check for Model type and construct the ViewModel accordingly, i.e. foreach(ProductBase currentProductBase in resultList) if (currentProductBase is SimpleProduct) viewModels.Add( new SimpleProductViewModel((SimpleProduct)currentProductBase)); else if (currentProductBase is ExtendedProduct) viewModels.Add( new ExtendedProductViewModels((ExtendedProduct)currentProductBase)); ... } ...but I consider this very bad practice as this code doesn't follow the object oriented design. The other way round, providing abstract Factory methods would reduce the code to: foreach(ProductBase currentProductBase in resultList) viewModels.Add(currentProductBase.CreateViewModel()) and would be perfectly extensible but since the Model doesn't know the ViewModels, that's not possible. I might bring interfaces into game here, but I haven't seen such approach proven yet. 2. How do i know which View to display when selecting a ViewModel? This is pretty the same problem, but on a higher level. Ended up finally having the desired ObservableCollection<ViewModelBase> collection would require the main view to choose a matching View for the ViewModel. In WPF, there is a DataTemplate concept which can supply a View upon a defined DataType. Unfortunately, this doesn't work in Silverlight and the only replacement I've found was the ResourceSelector of the SLExtensions toolkit which is buggy and not satisfying. Beside that, all problems from Question 1 apply as well. Do you have some hints or even a solution for the problems I describe, which you hopefully can understand from my explanation? Thank you in advance! Thomas

  Read the article

• What is `objc_msgSend_fixup`, exactly?

  - by Luis Antonio Botelho O. Leite

  I'm messing around with the Objective-C runtime, trying to compile objective-c code without linking it against libobjc, and I'm having some segmentation fault problems with a program, so I generated an assembly file from it. I think it's not necessary to show the whole assembly file. At some point of my main function, I've got the following line (which, by the way, is the line after which I get the seg fault): callq *l_objc_msgSend_fixup_alloc and here is the definition for l_objc_msgSend_fixup_alloc: .hidden l_objc_msgSend_fixup_alloc # @"\01l_objc_msgSend_fixup_alloc" .type l_objc_msgSend_fixup_alloc,@object .section "__DATA, __objc_msgrefs, coalesced","aw",@progbits .weak l_objc_msgSend_fixup_alloc .align 16 l_objc_msgSend_fixup_alloc: .quad objc_msgSend_fixup .quad L_OBJC_METH_VAR_NAME_ .size l_objc_msgSend_fixup_alloc, 16 I've reimplemented objc_msgSend_fixup as a function (id objc_msgSend_fixup(id self, SEL op, ...)) which returns nil (just to see what happens), but this function isn't even being called (the program crashes before calling it). So, my question is, what is callq *l_objc_msgSend_fixup_alloc supposed to do and what is objc_msgSend_fixup (after l_objc_msgSend_fixup_alloc:) supposed to be (a function or an object)? Edit To better explain, I'm not linking my source file against the objc library. What I'm trying to do is implement some parts of the libray, just to see how it works. Here is an approach of what I've done: #include <stdio.h> #include <objc/runtime.h> @interface MyClass { } +(id) alloc; @end @implementation MyClass +(id) alloc { // alloc the object return nil; } @end id objc_msgSend_fixup(id self, SEL op, ...) { printf("Calling objc_msgSend_fixup()...\n"); // looks for the method implementation for SEL in self's vtable return nil; // Since this is just a test, this function doesn't need to do that } int main(int argc, char *argv[]) { MyClass *m; m = [MyClass alloc]; // At this point, according to the assembly code generated // objc_msgSend_fixup should be called. So, the program should, at least, print // "Calling objc_msgSend_fixup()..." on the screen, but it crashes before // objc_msgSend_fixup() is called... return 0; } If the runtime needs to access the object's vtable to find the correct method to call, what is the function which actually does this? I think it is objc_msgSend_fixup, in this case. So, when objc_msgSend_fixup is called, it receives an object as one of its parameters, and, if this object hasn't been initialized, the function fails. So, I've implemented my own version of objc_msgSend_fixup. According to the assembly source above, it should be called. It doesn't matter if the function is actually looking for the implementation of the selector passed as parameter. I just want objc_msgSend_lookup to be called. But, it's not being called, that is, the function that looks for the object's data is not even being called, instead of being called and cause a fault (because it returns a nil (which, by the way, doesn't matter)). The program seg fails before objc_msgSend_lookup is called...

  Read the article

• Read variable-length records from a buffer - weird memory issues

  - by bsg

  Hi, I'm trying to implement an i/o intensive quicksort (C++ qsort) on a very large dataset. In the interests of speed, I'd like to read in a chunk of data at a time into a buffer and then use qsort to sort it inside the buffer. (I am currently working with text files but would like to move to binary soon.) However, my data is composed of variable-length records, and qsort needs to be told the length of the record in order to sort. Is there any way to standardize this? The only thing I could think of was rather convoluted: my program currently reads from the buffer until it hits a linefeed character ('10' in ascii), transferring each character over to another array. When it finds a linefeed (the delimiter in the input file), it fills the number of spaces remaining in the buffer for that record (record size is set to 30) with null characters. This way, I should end up with a buffer full of fixed-size records to give qsort. I know there are several problems with my approach, one being that it's just clumsy, another that the record size might conceivably be larger than 30, but is generally much less. Is there a better way of doing this? As well, my current code doesn't even work. When I debug it, it seems to be transferring characters from one buffer to the other, but when I try to print out the buffer, it contains only the first record. Here is my code: FILE *fp; unsigned char *buff; unsigned char *realbuff; FILE *inputFiles[NUM_INPUT_FILES]; buff = (unsigned char *) malloc(2048); realbuff = (unsigned char *) malloc(NUM_RECORDS * RECORD_SIZE); fp = fopen("postings0.txt", "r"); if(fp) { fread(buff, 1, 2048, fp); /*for(int i=0; i <30; i++) cout << buff[i] <<endl;*/ int y=0; int recordcounter = 0; //cout << buff; for(int i=0;i <100; i++) { if(buff[i] != char(10)) { realbuff[y] = buff[i]; y++; recordcounter++; } else { if(recordcounter < RECORD_SIZE) for(int j=recordcounter; j < RECORD_SIZE;j++) { realbuff[y] = char(0); y++; } recordcounter = 0; } } cout << realbuff <<endl; cout << buff; } else cout << "sorry"; Thank you very much, bsg

  Read the article

• Workflow for statistical analysis and report writing

  - by ws

  Does anyone have any wisdom on workflows for data analysis related to custom report writing? The use-case is basically this: Client commissions a report that uses data analysis, e.g. a population estimate and related maps for a water district. The analyst downloads some data, munges the data and saves the result (e.g. adding a column for population per unit, or subsetting the data based on district boundaries). The analyst analyzes the data created in (2), gets close to her goal, but sees that needs more data and so goes back to (1). Rinse repeat until the tables and graphics meet QA/QC and satisfy the client. Write report incorporating tables and graphics. Next year, the happy client comes back and wants an update. This should be as simple as updating the upstream data by a new download (e.g. get the building permits from the last year), and pressing a "RECALCULATE" button, unless specifications change. At the moment, I just start a directory and ad-hoc it the best I can. I would like a more systematic approach, so I am hoping someone has figured this out... I use a mix of spreadsheets, SQL, ARCGIS, R, and Unix tools. Thanks! PS: Below is a basic Makefile that checks for dependencies on various intermediate datasets (w/ ".RData" suffix) and scripts (".R" suffix). Make uses timestamps to check dependencies, so if you 'touch ss07por.csv', it will see that this file is newer than all the files / targets that depend on it, and execute the given scripts in order to update them accordingly. This is still a work in progress, including a step for putting into SQL database, and a step for a templating language like sweave. Note that Make relies on tabs in its syntax, so read the manual before cutting and pasting. Enjoy and give feedback! http://www.gnu.org/software/make/manual/html%5Fnode/index.html#Top R=/home/wsprague/R-2.9.2/bin/R persondata.RData : ImportData.R ../../DATA/ss07por.csv Functions.R $R --slave -f ImportData.R persondata.Munged.RData : MungeData.R persondata.RData Functions.R $R --slave -f MungeData.R report.txt: TabulateAndGraph.R persondata.Munged.RData Functions.R $R --slave -f TabulateAndGraph.R report.txt

  Read the article

• Persistent (purely functional) Red-Black trees on disk performance

  - by Waneck

  I'm studying the best data structures to implement a simple open-source object temporal database, and currently I'm very fond of using Persistent Red-Black trees to do it. My main reasons for using persistent data structures is first of all to minimize the use of locks, so the database can be as parallel as possible. Also it will be easier to implement ACID transactions and even being able to abstract the database to work in parallel on a cluster of some kind. The great thing of this approach is that it makes possible implementing temporal databases almost for free. And this is something quite nice to have, specially for web and for data analysis (e.g. trends). All of this is very cool, but I'm a little suspicious about the overall performance of using a persistent data structure on disk. Even though there are some very fast disks available today, and all writes can be done asynchronously, so a response is always immediate, I don't want to build all application under a false premise, only to realize it isn't really a good way to do it. Here's my line of thought: - Since all writes are done asynchronously, and using a persistent data structure will enable not to invalidate the previous - and currently valid - structure, the write time isn't really a bottleneck. - There are some literature on structures like this that are exactly for disk usage. But it seems to me that these techniques will add more read overhead to achieve faster writes. But I think that exactly the opposite is preferable. Also many of these techniques really do end up with a multi-versioned trees, but they aren't strictly immutable, which is something very crucial to justify the persistent overhead. - I know there still will have to be some kind of locking when appending values to the database, and I also know there should be a good garbage collecting logic if not all versions are to be maintained (otherwise the file size will surely rise dramatically). Also a delta compression system could be thought about. - Of all search trees structures, I really think Red-Blacks are the most close to what I need, since they offer the least number of rotations. But there are some possible pitfalls along the way: - Asynchronous writes -could- affect applications that need the data in real time. But I don't think that is the case with web applications, most of the time. Also when real-time data is needed, another solutions could be devised, like a check-in/check-out system of specific data that will need to be worked on a more real-time manner. - Also they could lead to some commit conflicts, though I fail to think of a good example of when it could happen. Also commit conflicts can occur in normal RDBMS, if two threads are working with the same data, right? - The overhead of having an immutable interface like this will grow exponentially and everything is doomed to fail soon, so this all is a bad idea. Any thoughts? Thanks! edit: There seems to be a misunderstanding of what a persistent data structure is: http://en.wikipedia.org/wiki/Persistent_data_structure

  Read the article

• Django Multi-Table Inheritance VS Specifying Explicit OneToOne Relationship in Models

  - by chefsmart

  Hope all this makes sense :) I'll clarify via comments if necessary. Also, I am experimenting using bold text in this question, and will edit it out if I (or you) find it distracting. With that out of the way... Using django.contrib.auth gives us User and Group, among other useful things that I can't do without (like basic messaging). In my app I have several different types of users. A user can be of only one type. That would easily be handled by groups, with a little extra care. However, these different users are related to each other in hierarchies / relationships. Let's take a look at these users: - Principals - "top level" users Administrators - each administrator reports to a Principal Coordinators - each coordinator reports to an Administrator Apart from these there are other user types that are not directly related, but may get related later on. For example, "Company" is another type of user, and can have various "Products", and products may be supervised by a "Coordinator". "Buyer" is another kind of user that may buy products. Now all these users have various other attributes, some of which are common to all types of users and some of which are distinct only to one user type. For example, all types of users have to have an address. On the other hand, only the Principal user belongs to a "BranchOffice". Another point, which was stated above, is that a User can only ever be of one type. The app also needs to keep track of who created and/or modified Principals, Administrators, Coordinators, Companies, Products etc. (So that's two more links to the User model.) In this scenario, is it a good idea to use Django's multi-table inheritance as follows: - from django.contrib.auth.models import User class Principal(User): # # # branchoffice = models.ForeignKey(BranchOffice) landline = models.CharField(blank=True, max_length=20) mobile = models.CharField(blank=True, max_length=20) created_by = models.ForeignKey(User, editable=False, blank=True, related_name="principalcreator") modified_by = models.ForeignKey(User, editable=False, blank=True, related_name="principalmodifier") # # # Or should I go about doing it like this: - class Principal(models.Model): # # # user = models.OneToOneField(User, blank=True) branchoffice = models.ForeignKey(BranchOffice) landline = models.CharField(blank=True, max_length=20) mobile = models.CharField(blank=True, max_length=20) created_by = models.ForeignKey(User, editable=False, blank=True, related_name="principalcreator") modified_by = models.ForeignKey(User, editable=False, blank=True, related_name="principalmodifier") # # # Please keep in mind that there are other user types that are related via foreign keys, for example: - class Administrator(models.Model): # # # principal = models.ForeignKey(Principal, help_text="The supervising principal for this Administrator") user = models.OneToOneField(User, blank=True) province = models.ForeignKey( Province) landline = models.CharField(blank=True, max_length=20) mobile = models.CharField(blank=True, max_length=20) created_by = models.ForeignKey(User, editable=False, blank=True, related_name="administratorcreator") modified_by = models.ForeignKey(User, editable=False, blank=True, related_name="administratormodifier") I am aware that Django does use a one-to-one relationship for multi-table inheritance behind the scenes. I am just not qualified enough to decide which is a more sound approach.

  Read the article

• Implementing a robust async stream reader for a console

  - by Jon

  I recently provided an answer to this question: C# - Realtime console output redirection. As often happens, explaining stuff (here "stuff" was how I tackled a similar problem) leads you to greater understanding and/or, as is the case here, "oops" moments. I realized that my solution, as implemented, has a bug. The bug has little practical importance, but it has an extremely large importance to me as a developer: I can't rest easy knowing that my code has the potential to blow up. Squashing the bug is the purpose of this question. I apologize for the long intro, so let's get dirty. I wanted to build a class that allows me to receive input from a Stream in an event-based manner. The stream, in my scenario, is guaranteed to be a FileStream and there is also an associated StreamReader already present to leverage. The public interface of the class is this: public class MyStreamManager { public event EventHandler<ConsoleOutputReadEventArgs> StandardOutputRead; public void StartSendingEvents(); public void StopSendingEvents(); } Obviously this specific scenario has to do with a console's standard output. StartSendingEvents and StopSendingEvents do what they advertise; for the purposes of this discussion, we can assume that events are always being sent without loss of generality. The class uses these two fields internally: protected readonly StringBuilder inputAccumulator = new StringBuilder(); protected readonly byte[] buffer = new byte[256]; The functionality of the class is implemented in the methods below. To get the ball rolling: public void StartSendingEvents(); { this.stopAutomation = false; this.BeginReadAsync(); } To read data out of the Stream without blocking, and also without requiring a carriage return char, BeginRead is called: protected void BeginReadAsync() { if (!this.stopAutomation) { this.StandardOutput.BaseStream.BeginRead( this.buffer, 0, this.buffer.Length, this.ReadHappened, null); } } The challenging part: BeginRead requires using a buffer. This means that when reading from the stream, it is possible that the bytes available to read ("incoming chunk") are larger than the buffer. Since we are only handing off data from the stream to a consumer, and that consumer may well have inside knowledge about the size and/or format of these chunks, I want to call event subscribers exactly once for each chunk. Otherwise the abstraction breaks down and the subscribers have to buffer the incoming data and reconstruct the chunks themselves using said knowledge. This is much less convenient to the calling code, and detracts from the usefulness of my class. Edit: There are comments below correctly stating that since the data is coming from a stream, there is absolutely nothing that the receiver can infer about the structure of the data unless it is fully prepared to parse it. What I am trying to do here is leverage the "flush the output" "structure" that the owner of the console imparts while writing on it. I am prepared to assume (better: allow my caller to have the option to assume) that the OS will pass me the data written between two flushes of the stream in exactly one piece. To this end, if the buffer is full after EndRead, we don't send its contents to subscribers immediately but instead append them to a StringBuilder. The contents of the StringBuilder are only sent back whenever there is no more to read from the stream (thus preserving the chunks). private void ReadHappened(IAsyncResult asyncResult) { var bytesRead = this.StandardOutput.BaseStream.EndRead(asyncResult); if (bytesRead == 0) { this.OnAutomationStopped(); return; } var input = this.StandardOutput.CurrentEncoding.GetString( this.buffer, 0, bytesRead); this.inputAccumulator.Append(input); if (bytesRead < this.buffer.Length) { this.OnInputRead(); // only send back if we 're sure we got it all } this.BeginReadAsync(); // continue "looping" with BeginRead } After any read which is not enough to fill the buffer, all accumulated data is sent to the subscribers: private void OnInputRead() { var handler = this.StandardOutputRead; if (handler == null) { return; } handler(this, new ConsoleOutputReadEventArgs(this.inputAccumulator.ToString())); this.inputAccumulator.Clear(); } (I know that as long as there are no subscribers the data gets accumulated forever. This is a deliberate decision). The good This scheme works almost perfectly: Async functionality without spawning any threads Very convenient to the calling code (just subscribe to an event) Maintains the "chunkiness" of the data; this allows the calling code to use inside knowledge of the data without doing any extra work Is almost agnostic to the buffer size (it will work correctly with any size buffer irrespective of the data being read) The bad That last almost is a very big one. Consider what happens when there is an incoming chunk with length exactly equal to the size of the buffer. The chunk will be read and buffered, but the event will not be triggered. This will be followed up by a BeginRead that expects to find more data belonging to the current chunk in order to send it back all in one piece, but... there will be no more data in the stream. In fact, as long as data is put into the stream in chunks with length exactly equal to the buffer size, the data will be buffered and the event will never be triggered. This scenario may be highly unlikely to occur in practice, especially since we can pick any number for the buffer size, but the problem is there. Solution? Unfortunately, after checking the available methods on FileStream and StreamReader, I can't find anything which lets me peek into the stream while also allowing async methods to be used on it. One "solution" would be to have a thread wait on a ManualResetEvent after the "buffer filled" condition is detected. If the event is not signaled (by the async callback) in a small amount of time, then more data from the stream will not be forthcoming and the data accumulated so far should be sent to subscribers. However, this introduces the need for another thread, requires thread synchronization, and is plain inelegant. Specifying a timeout for BeginRead would also suffice (call back into my code every now and then so I can check if there's data to be sent back; most of the time there will not be anything to do, so I expect the performance hit to be negligible). But it looks like timeouts are not supported in FileStream. Since I imagine that async calls with timeouts are an option in bare Win32, another approach might be to PInvoke the hell out of the problem. But this is also undesirable as it will introduce complexity and simply be a pain to code. Is there an elegant way to get around the problem? Thanks for being patient enough to read all of this.

  Read the article

• Writing Device Drivers for Microcontrollers, where to define IO Port pins?

  - by volting

  I always seem to encounter this dilemma when writing low level code for MCU's. I never know where to declare pin definitions so as to make the code as reusable as possible. In this case Im writing a driver to interface an 8051 to a MCP4922 12bit serial DAC. Im unsure how/where I should declare the pin definitions for The CS(chip select) and LDAC(data latch) for the DAC. At the moment there declared in the header file for the driver. Iv done a lot of research trying to figure out the best approach but havent really found anything. Im basically want to know what the best practices... if there are some books worth reading or online information, examples etc, any recommendations would be welcome. Just a snippet of the driver so you get the idea /** @brief This function is used to write a 16bit data word to DAC B -12 data bit plus 4 configuration bits @param dac_data A 12bit word @param ip_buf_unbuf_select Input Buffered/unbuffered select bit. Buffered = 1; Unbuffered = 0 @param gain_select Output Gain Selection bit. 1 = 1x (VOUT = VREF * D/4096). 0 =2x (VOUT = 2 * VREF * D/4096) */ void MCP4922_DAC_B_TX_word(unsigned short int dac_data, bit ip_buf_unbuf_select, bit gain_select) { unsigned char low_byte=0, high_byte=0; CS = 0; /**Select the chip*/ high_byte |= ((0x01 << 7) | (0x01 << 4)); /**Set bit to select DAC A and Set SHDN bit high for DAC A active operation*/ if(ip_buf_unbuf_select) high_byte |= (0x01 << 6); if(gain_select) high_byte |= (0x01 << 5); high_byte |= ((dac_data >> 8) & 0x0F); low_byte |= dac_data; SPI_master_byte(high_byte); SPI_master_byte(low_byte); CS = 1; LDAC = 0; /**Latch the Data*/ LDAC = 1; }

  Read the article

• How can I configure a Factory with the possible providers?

  - by Jonathas Costa

  I have three assemblies: "Framework.DataAccess", "Framework.DataAccess.NHibernateProvider" and "Company.DataAccess". Inside the assembly "Framework.DataAccess", I have my factory (with the wrong implementation of discovery): public class DaoFactory { private static readonly object locker = new object(); private static IWindsorContainer _daoContainer; protected static IWindsorContainer DaoContainer { get { if (_daoContainer == null) { lock (locker) { if (_daoContainer != null) return _daoContainer; _daoContainer = new WindsorContainer(new XmlInterpreter()); // THIS IS WRONG! THIS ASSEMBLY CANNOT KNOW ABOUT SPECIALIZATIONS! _daoContainer.Register( AllTypes.FromAssemblyNamed("Company.DataAccess") .BasedOn(typeof(IReadDao<>)).WithService.FromInterface(), AllTypes.FromAssemblyNamed("Framework.DataAccess.NHibernateProvider") .BasedOn(typeof(IReadDao<>)).WithService.Base()); } } return _daoContainer; } } public static T Create<T>() where T : IDao { return DaoContainer.Resolve<T>(); } } This assembly also defines the base interface for data access IReadDao: public interface IReadDao<T> { IEnumerable<T> GetAll(); } I want to keep this assembly generic and with no references. This is my base data access assembly. Then I have the NHibernate provider's assembly, which implements the above IReadDao using NHibernate's approach. This assembly references the "Framework.DataAccess" assembly. public class NHibernateDao<T> : IReadDao<T> { public NHibernateDao() { } public virtual IEnumerable<T> GetAll() { throw new NotImplementedException(); } } At last, I have the "Company.DataAccess" assembly, which can override the default implementation of NHibernate provider and references both previously seen assemblies. public interface IProductDao : IReadDao<Product> { Product GetByName(string name); } public class ProductDao : NHibernateDao<Product>, IProductDao { public override IEnumerable<Product> GetAll() { throw new NotImplementedException("new one!"); } public Product GetByName(string name) { throw new NotImplementedException(); } } I want to be able to write... IRead<Product> dao = DaoFactory.Create<IRead<Product>>(); ... and then get the ProductDao implementation. But I can't hold inside my base data access any reference to specific assemblies! My initial idea was to read that from a xml config file. So, my question is: How can I externally configure this factory to use a specific provider as my default implementation and my client implementation?

  Read the article

• Javascript HTML and Script injection issue in IE

  - by MartinHN

  Hi I have a javascript variable containing escaped HTML. There can be script tags inside the HTML, like this: var valueToInsert = "%3Cscript%20type%3D%22text/javascript%22%3Ealert%28%27test%27%29%3B%3C/script%3E%0A%3Cscript%20type%3D%22text/javascript%22%20src%3D%22http%3A//devserver/testinclude.js%22%3E%3C/script%3E%0A%3Cimg%20src%3D%22http%3A//www.footballpictures.net/data/media/131/manchester_united_logo.jpg%22%20/%3E" I want to append this to the DOM, and get all the javascript fired as expected. Right now I'm using this approach: var div = document.createElement("div"); div.innerHTML = unescape(valueToInsert); document.body.appendChild(div); In IE, at the time i set div.innerHTML - all script tags are removed. If I use jQuery to and do this: $(document.body).append(valueToInsert) It all works fine. Bad thing is, that I cannot use jQuery as this code will be added to sites I'm not in control of using some "already-implemented" script includes. Does someone have a trick? If jQuery can do it, it must be possible? I had another issue in Opera. I changed the injection script to be this: (still doesn't work in IE) var div = document.createElement("div"); div.innerHTML = unescape(valueToInsert); var a = new Array(); for (var i = 0; i < div.childNodes.length; i++) a.push(div.childNodes[i]); for (var i = 0; i < a.length; i++) { if (a[i].nodeName == "SCRIPT" && a[i].getAttribute("src") != null && a[i].getAttribute("src") != "" && typeof (a[i].getAttribute("src")) != "undefined") { var scriptTag = document.createElement("script"); scriptTag.src = a[i].getAttribute("src"); scriptTag.type = "text/javascript"; document.body.appendChild(scriptTag); } else if (a[i].nodeName == "SCRIPT") { eval(a[i].innerHTML); } else { document.body.appendChild(a[i]); } }

  Read the article

• JAX-WS wsgen and collections of collections: wsgen broken?

  - by ayang

  I've been playing around with "bottom-up" JAX-WS and have come across something odd when running wsgen. If I have a service class that does something like: @WebService public class Foo { public ArrayList<Bar> getBarList(String baz) { ... } } then running wsgen gets me a FooService_schema1.xsd that has something like this: <xs:complexType name="getBarListResponse"> <xs:sequence> <xs:element name="return" type="tns:bar" minOccurs="0" maxOccurs="unbounded"/> </xs:sequence> </xs:complexType> which seems reasonable. However, if I want a collection of collections like: public BarCollection getBarCollection(String baz) { ... } // BarCollection is just a container for an ArrayList<Bar> then the generated schema ends up with stuff like: <xs:complexType name="barCollection"> <xs:sequence/> </xs:complexType> <xs:complexType name="getBookCollectionsResponse"> <xs:sequence> <xs:element name="return" type="tns:barCollection" minOccurs="0" maxOccurs="unbounded"/> </xs:sequence> </xs:complexType> An empty sequence is not what I had in mind at all. My original approach was to go with: public ArrayList<ArrayList<Bar>> getBarLists(String baz) { ... } but that ends up with a big chain of complexTypes that just wind up with an empty sequence at the end as well: <xs:complexType name="getBarListsResponse"> <xs:sequence> <xs:element name="return" type="tns:arrayList" minOccurs="0" maxOccurs="unbounded"/> </xs:sequence> </xs:complexType> <xs:complexType name="arrayList"> <xs:complexContent> <xs:extension base="tns:abstractList"> <xs:sequence/> </xs:extension> </xs:complexContent> </xs:complexType> <xs:complexType name="abstractList" abstract="true"> <xs:complexContent> <xs:extension base="tns:abstractCollection"> <xs:sequence/> </xs:extension> </xs:complexContent> </xs:complexType> <xs:complexType name="abstractCollection" abstract="true"> <xs:sequence/> </xs:complexType> Am I missing something or is this a known hole in wsgen? JAXB? Andy

  Read the article

• Monitoring DOM Changes in JQuery

  - by user363866

  Is there a way to detect when the disabled attribute of an input changes in JQuery. I want to toggle the style based on the value. I can copy/paste the same enable/disable code for each change event (as I did below) but I was looking for a more generic approach. Can I create a custom event that will monitor the disabled attribute of specified inputs? Example: <style type="text/css">.disabled{ background-color:#dcdcdc; }</style> <fieldset> <legend>Option 1</legend> <input type="radio" name="Group1" id="Radio1" value="Yes" />Yes <input type="radio" name="Group1" id="Radio2" value="No" checked="checked" />No <div id="Group1Fields" style="margin-left: 20px;"> Percentage 1: <input type="text" id="Percentage1" disabled="disabled" /><br /> Percentage 2: <input type="text" id="Percentage2" disabled="disabled" /><br /> </div> </fieldset> <fieldset> <legend>Option 2</legend> <input type="radio" name="Group2" id="Radio3" value="Yes" checked="checked" />Yes <input type="radio" name="Group2" id="Radio4" value="No" />No <div id="Group2Fields" style="margin-left: 20px;"> Percentage 1: <input type="text" id="Text1" /><br /> Percentage 2: <input type="text" id="Text2" /><br /> </div> </fieldset> <script type="text/javascript"> $(document).ready(function () { //apply disabled style to all disabled controls $("input:disabled").addClass("disabled"); $("input[name='Group1']").change(function () { var disabled = ($(this).val() == "No") ? "disabled" : ""; $("#Group1Fields input").attr("disabled", disabled); //apply disabled style to all disabled controls $("input:disabled").addClass("disabled"); //remove disabled style to all enabled controls $("input:not(:disabled)").removeClass("disabled"); }); $("input[name='Group2']").change(function () { var disabled = ($(this).val() == "No") ? "disabled" : ""; $("#Group2Fields input").attr("disabled", disabled); //apply disabled style to all disabled controls $("input:disabled").addClass("disabled"); //remove disabled style to all enabled controls $("input:not(:disabled)").removeClass("disabled"); }); }); </script>

  Read the article

• Passing Objects between different files

  - by user309779

  Typically, if I want to pass an object to an instance of something I would do it like so... Listing 1 File 1: public class SomeClass { // Some Properties public SomeClass() { public int ID { get { return mID; } set { mID = value; } } public string Name { set { mName = value; } get { return mName; } } } } public class SomeOtherClass { // Method 1 private void Method1(int one, int two) { SomeClass USER; // Create an instance Squid RsP = new Squid(); RsP.sqdReadUserConf(USER); // Able to pass 'USER' to class method in different file. } } In this example, I was not able to use the above approach. Probably because the above example passes an object between classes. Whereas, below, things are defined in a single class. I had to use some extra steps (trial & error) to get things to work. I am not sure what I did here or what its called. Is it good programming practice? Or is there is an easier way to do this (like above). Listing 2 File 1: private void SomeClass1 { [snip] TCOpt_fM.AutoUpdate = optAutoUpdate.Checked; TCOpt_fM.WhiteList = optWhiteList.Checked; TCOpt_fM.BlackList = optBlackList.Checked; [snip] private TCOpt TCOpt_fM; TCOpt_fM.SaveOptions(TCOpt_fM); } File 2: public class TCOpt: { public TCOpt OPTIONS; [snip] private bool mAutoUpdate = true; private bool mWhiteList = true; private bool mBlackList = true; [snip] public bool AutoUpdate { get { return mAutoUpdate; } set { mAutoUpdate = value; } } public bool WhiteList { get { return mWhiteList; } set { mWhiteList = value; } } public bool BlackList { get { return mBlackList; } set { mBlackList = value; } } [snip] public bool SaveOptions(TCOpt OPTIONS) { [snip] Some things being written out to a file here [snip] Squid soSwGP = new Squid(); soSgP.sqdWriteGlobalConf(OPTIONS); } } File 3: public class SomeClass2 { public bool sqdWriteGlobalConf(TCOpt OPTIONS) { Console.WriteLine(OPTIONS.WhiteSites); // Nothing prints here Console.WriteLine(OPTIONS.BlackSites); // Or here } } Thanks in advance, XO

  Read the article

• show/hide html table columns using css

  - by Art Peterson

  I want to display a basic html table with controls to toggle showing/hiding of additional columns: <table id="mytable"> <tr> <th>Column 1</th> <th class="col1">1a</th> <th class="col1">1b</th> <th>Column 2</th> <th class="col2">2a</th> <th class="col2">2b</th> </tr> <tr> <td>100</td> <td class="col1">40</td> <td class="col1">60</td> <td>200</td> <td class="col2">110</td> <td class="col2">90</td> </tr> </table> So Column 1 and Column 2 will be the only columns displayed by default - but when you click on the Column 1 I want 1a and 1b to toggle, and same with Column 2 with 2a and 2b. I may end up with more columns and lots of rows - so any javascript looping approaches have been too slow to work with when I tested. The only approach that seems to be fast enough is to set up some css like this: table.hide1 .col1 { display: none; } table.hide2 .col2 { display: none; } table.hide3 .col3 { display: none; } table.show1 .col1 { display: table-cell; } table.show2 .col2 { display: table-cell; } table.show3 .col3 { display: table-cell; } And then set up onClick function calls on the table header cells that will trigger a toggle - and determine which css class to set "mytable" to that will create the toggle effect that I'm looking for. Is there an easy way to set this up so that the code can work for n # of columns?

  Read the article

• Adding NavigationControl to a TabBar Application containing UITableViews

  - by kungfuslippers

  Hi, I'm new to iPhone dev and wanted to get advice on the general design pattern / guide for putting a certain kind of app together. I'm trying to build a TabBar type application. One of the tabs needs to display a TableView and selecting a cell from within the table view will do something else - maybe show another table view or a web page. I need a Navigation Bar to be able to take me back from the table view/web page. The approach I've taken so far is to: Create an app based around UITabBarController as the rootcontroller i.e. @interface MyAppDelegate : NSObject <UIApplicationDelegate> { IBOutlet UIWindow *window; IBOutlet UITabBarController *rootController; } Create a load of UIViewController derived classes and associated NIBs and wire everything up in IB so when I run the app I get the basic tabs working. I then take the UIViewController derived class and modify it to the following: @interface MyViewController : UIViewController<UITableViewDataSource, UITableViewDelegate> { } and I add the delegate methods to the implementation of MyViewController - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 2; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; } if (indexPath.row == 0) { cell.textLabel.text = @"Mummy"; } else { cell.textLabel.text = @"Daddy"; } return cell; } Go back to IB , open MyViewController.xib and drop a UITableView onto it. Set the Files Owner to be MyViewController and then set the delegate and datasource of the UITableView to be MyViewController. If I run the app now, I get the table view appearing with mummy and daddy working nicely. So far so good. The question is how do I go about incorporating a Navigation Bar into my current code for when I implement: - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath() { // get row selected NSUInteger row = [indexPath row]; if (row == 0) { // Show another table } else if (row == 1) { // Show a web view } } Do I drop a NavigationBar UI control onto MyControllerView.xib ? Should I create it programmatically? Should I be using a UINavigationController somewhere ? I've tried dropping a NavigationBar onto my MyControllerView.xib in IB but its not shown when I run the app, only the TableView is displayed.

  Read the article

• Hibernate Communications Link Failure in Hibernate Based Java Servlet application powered by MySQL

  - by Vatsala

  Let me describe my question - I have a Java application - Hibernate as the DB interfacing layer over MySQL. I get the communications link failure error in my application. The occurence of this error is a very specific case. I get this error , When I leave mysql server unattended for more than approximately 6 hours (i.e. when there are no queries issued to MySQL for more than approximately 6 hours). I am pasting a top 'exception' level description below, and adding a pastebin link for a detailed stacktrace description. javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: Cannot open connection - Caused by: org.hibernate.exception.JDBCConnectionException: Cannot open connection - Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure - The last packet successfully received from the server was 1,274,868,181,212 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago. - Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure - The last packet successfully received from the server was 1,274,868,181,212 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago. - Caused by: java.net.ConnectException: Connection refused: connect the link to the pastebin for further investigation - http://pastebin.com/4KujAmgD What I understand from these exception statements is that MySQL is refusing to take in any connections after a period of idle/nil activity. I have been reading up a bit about this via google search, and came to know that one of the possible ways to overcome this is to set values for c3p0 properties as c3p0 comes bundled with Hibernate. Specifically, I read from here http://www.mchange.com/projects/c3p0/index.html that setting two properties idleConnectionTestPeriod and preferredTestQuery will solve this for me. But these values dont seem to have had an effect. Is this the correct approach to fixing this? If not, what is the right way to get over this? The following are related Communications Link Failure questions at stackoverflow.com, but I've not found a satisfactory answer in their answers. http://stackoverflow.com/questions/2121829/java-db-communications-link-failure http://stackoverflow.com/questions/298988/how-to-handle-communication-link-failure Note 1 - i dont get this error when I am using my application continuosly. Note 2 - I use JPA with Hibernate and hence my hibernate.dialect,etc hibernate properties reside within the persistence.xml in the META-INF folder (does that prevent the c3p0 properties from working?) edit - Here are the c3p0 parameters I tried out - select 1; 2

  Read the article

• XSLT, JSTL e JSF

  - by Paulo S.

  I have a xml file which I want to transform in a jsf code page. To do that I've created a xsl file. xml: <?xml version='1.0' encoding='ISO-8859-1'?> <questionario xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:noNamespaceSchemaLocation='Schema2.xsd'> <componente nome='input'> <id>input1</id> </componente> <componente nome='input'> <id>input2</id> </componente> </questionario> code: <%@ taglib uri="http://java.sun.com/jstl/core_rt" prefix="c" %> <%@ taglib uri="http://java.sun.com/jsp/jstl/xml" prefix="x" %> <c:set var="xml" value="${questionarioXSLBean.xml}"/> <c:set var="xsl"> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0" xmlns:f="http://java.sun.com/jsf/core" xmlns:h="http://java.sun.com/jsf/html" exclude-result-prefixes="f h"> <xsl:template match="/"> <xsl:for-each select="questionario/componente"> <xsl:if test="attribute::nome = 'input'"> <xsl:variable name="id"> <xsl:value-of select="id" /> </xsl:variable> <h:inputText id="{$id}"/> </xsl:if> </xsl:for-each> </xsl:template> </xsl:stylesheet> </c:set> <x:transform xml="${xml}" xslt="${xsl}" /> The problem is that nothing is shown in my screen because the generated code for <h:inputText id="input1"/> is <h:inputText id="input_1" xmlns:h="http://java.sun.com/jsf/html"/> how can I replace the xmlns:h="http://java.sun.com/jsf/html" or suppress it. Thanks! Update: Let me clarify what I want to do. I want to generate a jsf page dynamically depending on the attributes of a xml file, for instance, 2 input texts, 3 check boxes, etc. To make the transformation to jsf I thought in two approaches, one using jstl and another using xslt. The problem with the former is that I couldn't integrate jstl with jsf code (to set jsf components attributes using jstl variables) and with the last approach, I'm facing the problem described above.I wouldn't like to create components in java (UIComponents). Any suggestions?

  Read the article

< Previous Page | 392 393 394 395 396 397 398 399 400 401 402 403  | Next Page >