Search Results

Search found 37316 results on 1493 pages for 'model view controller'.

Page 328/1493 | < Previous Page | 324 325 326 327 328 329 330 331 332 333 334 335 | Next Page >

[Using $this when not in object context in] php error

- by JasonS

I have solved this problem, I just need to know what to do. I get the above error because I just realised that the class is being run as class::function($values) instead of class-function($values). Does anyone know how to convert this function to instantiate the class then run the function with values? private function _load($values=null) { define('LOADED_CONTROLLER', $this->controller); define('LOADED_FUNCTION', $this->function); $function = $this->function; $controller = new $this->controller; ($values == null) ? $controller->$function() : call_user_func_array(array($this->controller, $function), $values); }

Read the article
Dealing with C++ web views

- by Jeffrey

I'm working, as an hobby (before any one rage out of their mind, I'm just trying to study C++ regarding something I love: web. I'm not trying to reinvent your precious wheel, and I'm not trying to create the new web technology. I just have the time to go for it.), creating a web CGI C++ library. I'm at a pretty good point, but in the future I see one big problem: views. I'm used to the great <body><?php echo "Hey!"; ?></body> embedded php, but there's no such thing in C++, so I'm wondering: How would you deal with views? Would you create a simple find-replace-variable templating system and deal with thousands of partial views? For example: View view; view.load("header.html"); view.load("nav.html"); view.load("post_start.html"); for (int i = 0; i < 10; i++) { std::map<std::string, std::string> post; Post p(i); post = p.get(); view.load(post_view.html, post); // p is passed as argument and every `{% varname %}` in the html will be replaced with its value inside the map } view.load(post_end.html); view.load(footer); Would you create a simple templating system? So that we can deal with this C++ code: std::vector<std::map<std::string, std::string>> posts; Posts p; posts = p.getAll(); view.load(posts.html, posts); and then this HTML/TPL: <html> ... <body> <h2> Posts </h2> {% for (i = 0; i < 10; i++): %} <div class="post">...</div> {% endfor %} </body> </html> Is there any other way? What is the best way to do this? (And no, I don't think this is subjective question)

Read the article
UIPickerView in iphone

- by Harita

hi, i am making an application of iphone, in which i have a table view, on every row of table view i have created a button programmatically & on its click method am showing picker view. Picker view showing perfectly, on picker view's toolbar i have 2 barbuttonitem named Done & Cancel. i have added below code in Picker view's delegate method but button title is not changing with this delegate method static int _selectedRow; -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component { NSString *title = [pickarray objectAtIndex:_selectedRow]; //[pickarray removeObjectAtIndex:_selectedRow]; [pickarray insertObject:title atIndex:_selectedRow]; [table reloadData]; } Any ideas how to show selected row title on button?

Read the article
UITableViewCell select even doesn't work

- by saimun

I had a page control(UIPageControl) on a view (UIViewController) with table view (UITableView) on each page, each page have own table and can go to different view controller. i add the codes in "didSelectRowAtIndexPath" which can go to next level, is works perfect when i test it in a table view by itself, but it doesn't works when i have page controller with it. - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { [tableView deselectRowAtIndexPath:indexPath animated:YES]; if (pageNumber == 0) { PicturesViewController *picturesView = [[PicturesViewController alloc] init]; [self.navigationController pushViewController:picturesView animated:YES]; [picturesView release]; } else if (pageNumber == 1) { PictureDetailViewController *pictureDetailView = [[PictureDetailViewController alloc] init]; [self.navigationController pushViewController:pictureDetailView animated:YES]; [pictureDetailView release]; } else if (pageNumber == 2) { MessagesViewController *messagesView = [[MessagesViewController alloc] init]; [self.navigationController pushViewController:messagesView animated:YES]; [messagesView release]; } } here is the code, if view directly to this table view this code is work, how can i make it work under the pagecontrol??

Read the article
Click Listener not invoked within ListFragment

- by membersound

I'm extending a SherlockListFragment, but it should not matter as my question seems to be more general related to Fragments. Now, I implement a simple click listener for my list, but it does not get called. public class MyListFragment extends SherlockListFragment { @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View v = inflater.inflate(R.layout.list, container, false); v.setOnClickListener(new OnClickListener() { public void onClick(View view) { Log.i("debug", "single click"); } }); return v; } } Is anything wrong with this? //Solution: listView.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { Log.i("debug", "single click"); } });

Read the article
When the current toolbar is touched previous toolbar items are activated.

- by srikanth rongali

I have a UIToolBar *toolbar1. I have 3 buttons on the toolbar. And the tool bar is at the bottom of the view. The buttons are like library button, moreApps button, recordVideo button. If I touch the library button a new view(a UITableViewController) appears. I used presentModelViewController for it. If I touch moreApps button a new view (a UIViewController) appears and it loaded from http//. The recordButton touch gives another UIViewController view. When the moreApps button is touched and the view is loaded, it have the content from web and a UIToolBar *toolbar2 at the bottom the view. It has a refresh button and done button. The problem is when I touch the toolbar2 (not on the refresh button and done button) the previous views button are activated and corresponding views of previous buttons(library button, playVideo button) are loaded. I am not able to understand about this problem. Thank you.

Read the article
Django forms: prepopulate form with request.user and url parameter

- by Malyo

I'm building simple Course Management App. I want Users to sign up for Course. Here's sign up model: class CourseMembers(models.Model): student = models.ForeignKey(Student) course = models.ForeignKey(Course) def __unicode__(self): return unicode(self.student) Student model is extended User model - I'd like to fill the form with request.user. In Course model most important is course_id, which i'm passing into view throught URL parameter (for example http://127.0.0.1:8000/courses/course/1/). What i want to achieve, is to generate 'invisible' (so user can't change the inserted data) form with just input, but containing request.user and course_id parameter.

Read the article
Doubt about a particular pattern of Javascript class definition

- by fenderplayer

Recently i saw the following code that creates a class in javascript: var Model.Foo = function(){ // private stuff var a, b; // public properties this.attr1 = ''; this.attr2 = ''; if(Model.Foo._init === 'undefined'){ Model.Foo.prototype = { func1 : function(){ //...}, func2 : function(){ //... }, //other prototype functions } } Model.Foo._init = true; } // Instantiate and use the class as follows: var foo = new Model.Foo(); foo.func1(); I guess the _init variable is used to make sure we don't define the prototypes again. Also, i feel the code is more readable since i am placing everything in a function block (so in oop-speak, all attributes and methods are in one place). Do you see any issues with the code above? Any pitfalls of using this pattern if i need to create lots of classes in a big project?

Read the article
Defautlt Contoller in CodeIgniter

- by gregavola

Hello everyone, I am wondering if there is any other configuration options for a default controller. For example - if I have a controller called "site" and I set the default controller in the following file: application/config/routes.php to: $route['default_controller'] = "site"; I should be able to go to http://localhost and that brings up the index(); function in the site controller. However, if I try to do go to http://localhost/index.php/index2 to load the index2(); function I get a 404 error. If i change the URL to http://localhost/index.php/site/index2 it works fine - but I thought already set the default controller. Is there any way around this? Any thoughts?

Read the article
How To Draw line on touch event ?

- by AJPatel

Hey i m beginner of objective C Please Help me i make following code but not work..... -(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; if ([touch view] == self.view) { CGPoint location = [touch locationInView:self.view]; loc1 = location; CGContextMoveToPoint(context, location.x, location.y); NSLog(@"x:%d y:%d At Touch Begain", loc1.x, loc1.y); } } - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; if ([touch view] == self.view) { CGPoint location = [touch locationInView:self.view]; CGContextMoveToPoint(context, loc1.x, loc1.y); NSLog(@"x:%d y:%d At Touch Move", loc1.x, loc1.y); CGContextAddLineToPoint(context, location.x, location.y); NSLog(@"x:%d y:%d", location.x, location.y); } }

Read the article
UITableView - centering of Sections

- by Raj

Hi all, I am using a table view with its style set as "Grouped". I have only 2 sections to be displayed in the table view and the table view does not occupy full iPhone screen (It has some other views with it). So I would like to display those 2 sections centered in the table view rather than displaying the sections from the top of table view. One round about way is to set header and footer of the table view appropriately. But the disadvantage of this is, each sections will be equidistant (looks awkward!). Anybody with solutions to it? Thanks, Raj

Read the article
How to I initialize a class with an interface button clicked? [Objective - C]

- by seaworthy

I am having a problem with figuring out how to initialize a class with button clicked. The code is listed below the line I have a problem with has "HELP NEEDED HERE" comment above it. // // Controller.m // #import "Controller.h" @implementation Controller - (id)init { self = [super init]; if(self){ numberTotal = 0; //HELP NEEDED HERE [self btnScore_Clicked:(id)sender]; } return self;} - (IBAction) btnScore_Clicked:(id)sender { numberTotal += 1; NSLog(@"Number Total: %d",numberTotal); } - (void)dealloc { [super dealloc]; } @end // // Controller.h // #import <UIKit/UIKit.h> @interface Controller : UIViewController { NSInteger numberTotal; } - (IBAction) btnScore_Clicked:(id)sender; @end Thanks!

Read the article
Default Contoller in CodeIgniter

- by gregavola

I am wondering if there is any other configuration options for a default controller. For example - if I have a controller called "site" and I set the default controller in the following file: application/config/routes.php to: $route['default_controller'] = "site"; I should be able to go to http://localhost and that brings up the index(); function in the site controller. However, if I try to do go to http://localhost/index.php/index2 to load the index2(); function I get a 404 error. If I change the URL to http://localhost/index.php/site/index2 it works fine - but I thought already set the default controller. Is there any way around this?

Read the article
web service data type (contract)

- by cyberguest

hi, i have a general design question. we have a fairly big data model that represents an clinical object, the object itself has 200+ child attributes in the hierarchy. and we have a SetObject operation, and a GetObject operation. my question is, best practice wise, would it make sense to use that single data model in both operations or different data model for each? Because the Get operation will return much more details than what's needed for Set. an example of what i mean: the data model has say ProviderId, and ProviderName attributes, in the Get operation, both the ProviderId, and ProviderName would need to be returned. However, in the Set operation, only the ProviderId is needed, and ProviderName is ignored by the service since system has that information already. In this case, if the Get and Set operations use the same data model, the ProviderName is exposed even for Set operation, does that confuse the consuming developer?

Read the article
Collision detection on sub views contained in 2 separate parent UIViews?

- by Chris

Hi All, I originally setup some conditions using CGRectIntersectsRect for some collision detection which worked fine. In the greater scale of things I only need part of the view to be detected. So originally within the ViewController it was comparing 2 UIviews. Now what I need to do is collision detection of subViews within 2 different UIViews that are contained in a view in which the view controller does the logic. My script is no longer working as I suspect CGRectIntersectsRect only compares frames within the same view? I'll keep digging to confirm this. Any ways around this? Is it possible for example to get the x and y pos of the sub view in relation to the main view that's performing the logic?

Read the article
How do I filter values in a Django form using ModelForm?

- by malandro95

I am trying to use the ModelForm to add my data. It is working well, except that the ForeignKey dropdown list is showing all values and I only want it to display the values that a pertinent for the logged in user. Here is my model for ExcludedDate, the record I want to add: class ExcludedDate(models.Model): date = models.DateTimeField() reason = models.CharField(max_length=50) user = models.ForeignKey(User) category = models.ForeignKey(Category) recurring = models.ForeignKey(RecurringExclusion) def __unicode__(self): return self.reason Here is the model for the category, which is the table containing the relationship that I'd like to limit by user: class Category(models.Model): name = models.CharField(max_length=50) user = models.ForeignKey(User, unique=False) def __unicode__(self): return self.name And finally, the form code: class ExcludedDateForm(ModelForm): class Meta: model = models.ExcludedDate exclude = ('user', 'recurring',) How do I get the form to display only the subset of categories where category.user equals the logged in user?

Read the article
How do submit an object to a struts2 action using jQuery?

- by James Drinkard

I have an object that I'm populating from a selection off a table row that a user selects. I have a jQuery function that captures the click event and a hidden form field populates an id I need. However, I'm not sure as to the proper way to send off that object to a struts2 action? I tried using this: $(function() { $('#tbl tr').click(function() { var id = $(this).closest('tr').find('input:hidden').val(); var page = "<s:url action='update/deleteInfo.action'/>?model.isDelete=true&model.info.id=id"; console.log(page); window.location.href=(page); }); }); The model object has an isDelete boolean variable and the model has a nested info object that has an id variable with getter/setters. However, when I send this across, the model object isn't populated with these entries. Is there a way to do this or a better way than the url tag?

Read the article
Does my use of the strategy pattern violate the fundamental MVC pattern in iOS?

- by Goodsquirrel

I'm about to use the 'strategy' pattern in my iOS app, but feel like my approach violates the somehow fundamental MVC pattern. My app is displaying visual "stories", and a Story consists (i.e. has @properties) of one Photo and one or more VisualEvent objects to represent e.g. animated circles or moving arrows on the photo. Each VisualEvent object therefore has a eventType @property, that might be e.g. kEventTypeCircle or kEventTypeArrow. All events have things in common, like a startTime @property, but differ in the way they are being drawn on the StoryPlayerView. Currently I'm trying to follow the MVC pattern and have a StoryPlayer object (my controller) that knows about both the model objects (like Story and all kinds of visual events) and the view object StoryPlayerView. To chose the right drawing code for each of the different visual event types, my StoryPlayer is using a switch statement. @implementation StoryPlayer // (...) - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { switch (event.eventType) { case kEventTypeCircle: [self showCircleEvent:event onStoryPlayerView:storyPlayerView]; break; case kEventTypeArrow: [self showArrowDrawingEvent:event onStoryPlayerView:storyPlayerView]; break; // (...) } But switch statements for type checking are bad design, aren't they? According to Uncle Bob they lead to tight coupling and can and should almost always be replaced by polymorphism. Having read about the "Strategy"-Pattern in Head First Design Patterns, I felt this was a great way to get rid of my switch statement. So I changed the design like this: All specialized visual event types are now subclasses of an abstract VisualEvent class that has a showOnStoryPlayerView: method. @interface VisualEvent : NSObject - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView; // abstract Each and every concrete subclass implements a concrete specialized version of this drawing behavior method. @implementation CircleVisualEvent - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView { [storyPlayerView drawCircleAtPoint:self.position color:self.color lineWidth:self.lineWidth radius:self.radius]; } The StoryPlayer now simply calls the same method on all types of events. @implementation StoryPlayer - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { [event showOnStoryPlayerView:storyPlayerView]; } The result seems to be great: I got rid of the switch statement, and if I ever have to add new types of VisualEvents in the future, I simply create new subclasses of VisualEvent. And I won't have to change anything in StoryPlayer. But of cause this approach violates the MVC pattern since now my model has to know about and depend on my view! Now my controller talks to my model and my model talks to the view calling methods on StoryPlayerView like drawCircleAtPoint:color:lineWidth:radius:. But this kind of calls should be controller code not model code, right?? Seems to me like I made things worse. I'm confused! Am I completely missing the point of the strategy pattern? Is there a better way to get rid of the switch statement without breaking model-view separation?

Read the article
C# 5 Async, Part 2: Asynchrony Today

- by Reed

The .NET Framework has always supported asynchronous operations. However, different mechanisms for supporting exist throughout the framework. While there are at least three separate asynchronous patterns used through the framework, only the latest is directly usable with the new Visual Studio Async CTP. Before delving into details on the new features, I will talk about existing asynchronous code, and demonstrate how to adapt it for use with the new pattern. The first asynchronous pattern used in the .NET framework was the Asynchronous Programming Model (APM). This pattern was based around callbacks. A method is used to start the operation. It typically is named as BeginSomeOperation. This method is passed a callback defined as an AsyncCallback, and returns an object that implements IAsyncResult. Later, the IAsyncResult is used in a call to a method named EndSomeOperation, which blocks until completion and returns the value normally directly returned from the synchronous version of the operation. Often, the EndSomeOperation call would be called from the callback function passed, which allows you to write code that never blocks. While this pattern works perfectly to prevent blocking, it can make quite confusing code, and be difficult to implement. For example, the sample code provided for FileStream’s BeginRead/EndRead methods is not simple to understand. In addition, implementing your own asynchronous methods requires creating an entire class just to implement the IAsyncResult. Given the complexity of the APM, other options have been introduced in later versions of the framework. The next major pattern introduced was the Event-based Asynchronous Pattern (EAP). This provides a simpler pattern for asynchronous operations. It works by providing a method typically named SomeOperationAsync, which signals its completion via an event typically named SomeOperationCompleted. The EAP provides a simpler model for asynchronous programming. It is much easier to understand and use, and far simpler to implement. Instead of requiring a custom class and callbacks, the standard event mechanism in C# is used directly. For example, the WebClient class uses this extensively. A method is used, such as DownloadDataAsync, and the results are returned via the DownloadDataCompleted event. While the EAP is far simpler to understand and use than the APM, it is still not ideal. By separating your code into method calls and event handlers, the logic of your program gets more complex. It also typically loses the ability to block until the result is received, which is often useful. Blocking often requires writing the code to block by hand, which is error prone and adds complexity. As a result, .NET 4 introduced a third major pattern for asynchronous programming. The Task<T> class introduced a new, simpler concept for asynchrony. Task and Task<T> effectively represent an operation that will complete at some point in the future. This is a perfect model for thinking about asynchronous code, and is the preferred model for all new code going forward. Task and Task<T> provide all of the advantages of both the APM and the EAP models – you have the ability to block on results (via Task.Wait() or Task<T>.Result), and you can stay completely asynchronous via the use of Task Continuations. In addition, the Task class provides a new model for task composition and error and cancelation handling. This is a far superior option to the previous asynchronous patterns. The Visual Studio Async CTP extends the Task based asynchronous model, allowing it to be used in a much simpler manner. However, it requires the use of Task and Task<T> for all operations.

Read the article
MVC Portable Areas – Static Files as Embedded Resources

- by Steve Michelotti

This is the third post in a series related to build and deployment considerations as I’ve been exploring MVC Portable Areas: #1 – Using Web Application Project to build portable areas #2 – Conventions for deploying portable area static files #3 – Portable area static files as embedded resources In the last post, I walked through a convention for managing static files. In this post I’ll discuss another approach to manage static files (e.g., images, css, js, etc.). With this approach, you *also* compile the static files as embedded resources into the assembly similar to the *.aspx pages. Once again, you can set this to happen automatically by simply modifying your *.csproj file to include the desired extensions so you don’t have to remember every time you add a file: 1: <Target Name="BeforeBuild"> 2: <ItemGroup> 3: <EmbeddedResource Include="**\*.aspx;**\*.ascx;**\*.gif;**\*.css;**\*.js" /> 4: </ItemGroup> 5: </Target> We now need a reliable way to serve up these static files that are embedded in the assembly. There are a couple of ways to do this but one way is to simply create a Resource controller whose job is dedicated to doing this. 1: public class ResourceController : Controller 2: { 3: public ActionResult Index(string resourceName) 4: { 5: var contentType = GetContentType(resourceName); 6: var resourceStream = Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName); 7: 8: return this.File(resourceStream, contentType); 9: return View(); 10: } 11: 12: private static string GetContentType(string resourceName) 13: { 14: var extention = resourceName.Substring(resourceName.LastIndexOf('.')).ToLower(); 15: switch (extention) 16: { 17: case ".gif": 18: return "image/gif"; 19: case ".js": 20: return "text/javascript"; 21: case ".css": 22: return "text/css"; 23: default: 24: return "text/html"; 25: } 26: } 27: } In order to use this controller, we need to make sure we’ve registered the route in our portable area registration (shown in lines 5-6): 1: public class WidgetAreaRegistration : PortableAreaRegistration 2: { 3: public override void RegisterArea(System.Web.Mvc.AreaRegistrationContext context, IApplicationBus bus) 4: { 5: context.MapRoute("ResourceRoute", "widget1/resource/{resourceName}", 6: new { controller = "Resource", action = "Index" }); 7: 8: context.MapRoute("Widget1", "widget1/{controller}/{action}", new 9: { 10: controller = "Home", 11: action = "Index" 12: }); 13: 14: RegisterTheViewsInTheEmbeddedViewEngine(GetType()); 15: } 16: 17: public override string AreaName 18: { 19: get { return "Widget1"; } 20: } 21: } In my previous post, we relied on a custom Url helper method to find the actual physical path to the static file like this: 1: <img src="<%: Url.AreaContent("/images/arrow.gif") %>" /> Hello World! However, since we are now embedding the files inside the assembly, we no longer have to worry about the physical path. We can change this line of code to this: 1: <img src="<%: Url.Resource("Widget1.images.arrow.gif") %>" /> Hello World! Note that I had to fully quality the resource name (with namespace and physical location) since that is how .NET assemblies store embedded resources. I also created my own Url helper method called Resource which looks like this: 1: public static string Resource(this UrlHelper urlHelper, string resourceName) 2: { 3: var areaName = (string)urlHelper.RequestContext.RouteData.DataTokens["area"]; 4: return urlHelper.Action("Index", "Resource", new { resourceName = resourceName, area = areaName }); 5: } This method gives us the convenience of not having to know how to construct the URL – but just allowing us to refer to the resource name. The resulting html for the image tag is: 1: <img src="/widget1/resource/Widget1.images.arrow.gif" /> so we can always request any image from the browser directly. This is almost analogous to the WebResource.axd file but for MVC. What is interesting though is that we can encapsulate each one of these so that each area can have it’s own set of resources and they are easily distinguished because the area name is the first segment of the route. This makes me wonder if something like this ResourceController should be baked into portable areas itself. I’m definitely interested in anyone has any opinions on it or have taken alternative approaches.

Read the article
Removing Barriers to Create Effective Data Models

After years of creating and maintaining data models, I have started to notice common barriers that decrease the accuracy and usefulness of models. In my opinion, the main causes of these barriers are the lack of knowledge and communication from within a company. The lack of knowledge in regards to data models or data modeling can take many forms. Company Culture Knowledge Whether documented or undocumented, existing business rules of a company can affect how data is modeled. For example, if a company only allows 1 assigned person per customer to be able to manipulate a customer’s record then then a data model that includes an associated table that joins customers and employee’s would be unneeded because that would allow for the possibility of multiple employees to handle a customer because of the potential for a many to many relationship between Customers and Employees. Technical Knowledge Depending on the data modeler’s proficiency in modeling data they can inadvertently cause issues and/or complications with a design without even noticing. It is important that companies share data modeling responsibilities so that the models are developed from multiple perspectives of a system, company and the original problem. In addition, the tools that a company selects to create data models can also affect the accuracy of the model if designer are not familiar with the tools or the tools are too complex to use for the designer. Existing System Knowledge In order for a data modeler to model data for an existing system so that new changes can be applied to a system then they need to at least know the basic concepts of a system so that they can work within it. This will promote reusability of data and prevent the chance of duplicating data. Project Knowledge This should be pretty obvious, but it is very hard to create an accurate data model without knowing what data needs to be modeled. I have always found it strange that I have been asked to start modeling data prior to a client formalizing any requirements. Usually when this happens I have to make several iterations to a model, and the client still does not know exactly what they want. In addition additional issues can arise when certain stakeholders of a project are not consulted prior to the design or after the project is over because it can cause miss understandings and confusion by the end user as well as possibly not solving the original problem for which a project is intended to solve. One common thread between each type of knowledge is that they can all be avoided through the use of good communication. For example, if a modeler is new to a company then they should ask older employees about any business specific rules that may be documented or undocumented that must be applied to projects in general. Furthermore, if a modeler is not really familiar with a specific data modeling software then they need to speak up and ask for help form other employees or their manager. This will not only help the modeler in the project, but also help them in future projects that they do for the company. Additionally, if a project is not clearly defined prior to a data modeler being assigned the modeling project then it is their responsibility to communicate with the other stakeholders to clarify any part of a project that is unclear so that the data model that is created is accurately aligned with a project.

Read the article
Doubts about several best practices for rest api + service layer

- by TheBeefMightBeTough

I'm going to be starting a project soon that exposes a restful api for business intelligence. It may not be limited to a restful api, so I plan to delegate requests to a service layer that then coordinates multiple domain objects (each of which have business logic local to the object). The api will likely have many calls as it is a long-term project. While thinking about the design, I recalled a few best practices. 1) Use command objects at the controller layer (I'm using Spring MVC). 2) Use DTOs at the service layer. 3) Validate in both the controller and service layer, though for different reasons. I have my doubts about these recommendations. 1) Using command objects adds a lot of extra single-purpose classes (potentially one per request). What exactly is the benefit? Annotation based validation can be done using this approach, sure. What if I have two requests that take the same parameters, but have different validation requirements? I would have to have two different classes with exactly the same members but different annotations? Bleh. 2) I have heard that using DTOs is preferable to parameters because it makes for more maintainable code down the road (say, e.g., requirements change and the service parameters need to be altered). I don't quite understand this. Shouldn't an api be more-or-less set in stone? I would understand that in the early phases of a project (or, especially, an entire company) the domain itself will not be well understood, and thus core domain objects may change along with the apis that manipulate these objects. At this point however the number of api methods should be small and their dependents few, so changes to the methods could easily be tolerated from a maintainability standpoint. In a large api with many methods and a substantial domain model, I would think having a DTO for potentially each domain object would become unwieldy. Am I misunderstanding something here? 3) I see validation in the controller and service layer as redundant in most cases. Why would I validate that parameters are not null and are in general well formed in the controller if the service is going to do exactly the same (and more). Couldn't I just do all the validation in the service and throw a runtime exception with a list of bad parameters then catch that in the controller to make the error messages more presentable? Better yet, couldn't I just make the error messages user-friendly in the service and let the exception trickle up to a global handler (ControllerAdvice in spring, for example)? Is there something wrong with either of these approaches? (I do see a use case for controller validation if the input does not map one-to-one with the service input, but since the controllers are for a rest api and not forms, the api parameters will probably map directly to service parameters.) I do also have a question about unchecked vs checked exceptions. Namely, I'm not really sure why I'd ever want to use a checked exception. Every time I have seen them used they just get wrapped into general exceptions (DomainException, SystemException, ApplicationException, w/e) to reduce the signature length of methods, or devs catch Exception rather than dealing with the App1Exception, App2Exception, Sys1Exception, Sys2Exception. I don't see how either of these practices is very useful. Why not just use unchecked exceptions always and catch the ones you actually do care about? You could just document what unchecked exceptions the method throws.

Read the article
Come up with a real-world problem in which only the best solution will do (a problem from Introduction to algorithms) [closed]

- by Mike

EDITED (I realized that the question certainly needs a context) The problem 1.1-5 in the book of Thomas Cormen et al Introduction to algorithms is: "Come up with a real-world problem in which only the best solution will do. Then come up with one in which a solution that is “approximately” the best is good enough." I'm interested in its first statement. And (from my understanding) it is asked to name a real-world problem where only the exact solution will work as opposed to a real-world problem where good-enough solution will be ok. So what is the difference between the exact and good enough solution. Consider some physics problem for example the simulation of the fulid flow in the permeable medium. To make this simulation happen some simplyfing assumptions have to be made when deriving a mathematical model. Otherwise the model becomes at least complex and unsolvable. Virtually any particle in the universe has its influence on the fluid flow. But not all particles are equal. Those that form the permeable medium are much more influental than the ones located light years away. Then when the mathematical model needs to be solved an exact solution can rarely be found unless the mathematical model is simple enough (wich probably means the model isn't close to reality). We take an approximate numerical method and after hours of coding and days of verification come up with the program or algorithm which is a solution. And if the model and an algorithm give results close to a real problem by some degree that is good enough soultion. Its worth noting the difference between exact solution algorithm and exact computation result. When considering real-world problems and real-world computation machines I believe all physical problems solutions where any calculations are taken can not be exact because universal physical constants are represented approximately in the computer. Any numbers are represented with the limited precision, at least limited by amount of memory available to computing machine. I can imagine plenty of problems where good-enough, good to some degree solution will work, like train scheduling, automated trading, satellite orbit calculation, health care expert systems. In that cases exact solutions can't be derived due to constraints on computation time, limitations in computer memory or due to the nature of problems. I googled this question and like what this guy suggests: there're kinds of mathematical problems that need exact solutions (little note here: because the question is taken from the book "Introduction to algorithms" the term "solution" means an algorithm or a program, which in this case gives exact answer on each input). But that's probably more of theoretical interest. So I would like to narrow down the question to: What are the real-world practical problems where only the best (exact) solution algorithm or program will do (but not the good-enough solution)? There are problems like breaking of cryptographic ciphers where only exact solution matters in practice and again in practice the process of deciphering without knowing a secret should take reasonable amount of time. Returning to the original question this is the problem where good-enough (fast-enough) solution will do there's no practical need in instant crack though it's desired. So the quality of "best" can be understood in any sense: exact, fastest, requiring least memory, having minimal possible network traffic etc. And still I want this question to be theoretical if possible. In a sense that there may be example of computer X that has limited resource R of amount Y where the best solution to problem P is the one that takes not more than available Y for inputs of size N*Y. But that's the problem of finding solution for P on computer X which is... well, good enough. My final thought that we live in a world where it is required from programming solutions to practical purposes to be good enough. In rare cases really very very good but still not the best ones. Isn't it? :) If it's not can you provide an example? Or can you name any such unsolved problem of practical interest?

Read the article
Python regex to parse text file, get the items in list and count the list

- by Nemo

I have a text file which contains some data. I m particularly interested in finding the count of the number of items in v_dims v_dims pattern in my text file looks like this : v_dims={ "Sales", "Product Family", "Sales Organization", "Region", "Sales Area", "Sales office", "Sales Division", "Sales Person", "Sales Channel", "Sales Order Type", "Sales Number", "Sales Person", "Sales Quantity", "Sales Amount" } So I m thinking of getting all the elements in v_dims and dumping them out in a Python list. Then compute the len(mylist) to get the count of the items. The challenge is in getting all the elements of v_dims from my text file and putting them in an empty list. I m particularly interested in items in v_dims in my text file. The text file has data in the form of v_dims pattern i showed in my original post. Some data has nested patterns of v_dims. Thanks. Here's what I have tried and failed. Any help is appreciated. TIA. import re fname = "C:\Users\XXXX\Test.mrk" with open(fname, "r") as fo: content_as_string = fo.read() match = re.findall(r'v_dims={\"(.+?)\"}',content_as_string) Though I have a big text file, Here's a snippet of what's the structure of my text file version "1"; // Computer generated object language file object 'MRKR' "Main" { Data_Type=2, HeaderBlock={ Version_String="6.3 (25)" }, Printer_Info={ Orientation=0, Page_Width=8.50000000, Page_Height=11.00000000, Page_Header="", Page_Footer="", Margin_type=0, Top_Margin=0.50000000, Left_Margin=0.50000000, Bottom_Margin=0.50000000, Right_Margin=0.50000000 }, Marker_Options={ Close_All="TRUE", Hide_Console="FALSE", Console_Left="FALSE", Console_Width=217, Main_Style="Maximized", MDI_Rect={ 0, 0, 892, 1063 } }, Dives={ { Dive="A", Windows={ { View_Index=0, Window_Info={ Window_Rect={ 0, -288, 400, 1008 }, Window_Style="Maximized Front", Window_Name="Theater [Previous Qtr Diveplan-Dive A]" }, Dependent_bool="FALSE", Colset={ Dive_Type="Normal", Dimension_Name="Theater", Action_List={ Actions={ { Action_Type="Select", select_type=5 }, { Action_Type="Select", select_type=0, Key_Names={ "Theater" }, Key_Indexes={ { "AMERICAS" } } }, { Action_Type="Focus", Focus_Rows="True" }, { Action_Type="Dimensions", v_dims={ "Theater", "Product Family", "Division", "Region", "Install at Country Name", "Connect Home Type", "Connect In Type", "SymmConnect Enabled", "Connect Home Refusal Reason", "Sales Order Channel Type", "Maintained By Group", "PS Flag", "Avalanche Flag", "Product Item Family" }, Xtab_Bool="False", Xtab_Flip="False" }, { Action_Type="Select", select_type=5 }, { Action_Type="Select", select_type=0, Key_Names={ "Theater", "Product Family", "Division", "Region", "Install at Country Name", "Connect Home Type", "Connect In Type", "SymmConnect Enabled", "Connect Home Refusal Reason", "Sales Order Channel Type", "Maintained By Group", "PS Flag", "Avalanche Flag" }, Key_Indexes={ { "AMERICAS", "ATMOS", "Latin America CS Division", "37000 CS Region", "Mexico", "", "", "", "", "DIRECT", "EMC", "N", "0" } } } } }, Num_Palette_cols=0, Num_Palette_rows=0 }, Format={ Window_Type="Tabular", Tabular={ Num_row_labels=8 } } } } } }, Widget_Set={ Widget_Layout="Vertical", Go_Button=1, Picklist_Width=0, Sort_Subset_Dimensions="TRUE", Order={ } }, Views={ { Data_Type=1, dbname="Previous Qtr Diveplan", diveline_dbname="Current Qtr Diveplan", logical_name="Current Qtr Diveplan", cols={ { name="Total TSS installs", column_type="Calc[Total TSS installs]", output_type="Number", format_string="." }, { name="TSS Valid Connectivity Records", column_type="Calc[TSS Valid Connectivity Records]", output_type="Number", format_string="." }, { name="% TSS Connectivity Record", column_type="Calc[% TSS Connectivity Record]", output_type="Number" }, { name="TSS Not Applicable", column_type="Calc[TSS Not Applicable]", output_type="Number", format_string="." }, { name="TSS Customer Refusals", column_type="Calc[TSS Customer Refusals]", output_type="Number", format_string="." }, { name="% TSS Refusals", column_type="Calc[% TSS Refusals]", output_type="Number" }, { name="TSS Eligible for Physical Connectivity", column_type="Calc[TSS Eligible for Physical Connectivity]", output_type="Number", format_string="." }, { name="TSS Boxes with Physical Connectivty", column_type="Calc[TSS Boxes with Physical Connectivty]", output_type="Number", format_string="." }, { name="% TSS Physical Connectivity", column_type="Calc[% TSS Physical Connectivity]", output_type="Number" } }, dim_cols={ { name="Model", column_type="Dimension[Model]", output_type="None" }, { name="Model", column_type="Dimension[Model]", output_type="None" }, { name="Connect In Type", column_type="Dimension[Connect In Type]", output_type="None" }, { name="Connect Home Type", column_type="Dimension[Connect Home Type]", output_type="None" }, { name="SymmConnect Enabled", column_type="Dimension[SymmConnect Enabled]", output_type="None" }, { name="Theater", column_type="Dimension[Theater]", output_type="None" }, { name="Division", column_type="Dimension[Division]", output_type="None" }, { name="Region", column_type="Dimension[Region]", output_type="None" }, { name="Sales Order Number", column_type="Dimension[Sales Order Number]", output_type="None" }, { name="Product Item Family", column_type="Dimension[Product Item Family]", output_type="None" }, { name="Item Serial Number", column_type="Dimension[Item Serial Number]", output_type="None" }, { name="Sales Order Deal Number", column_type="Dimension[Sales Order Deal Number]", output_type="None" }, { name="Item Install Date", column_type="Dimension[Item Install Date]", output_type="None" }, { name="SYR Last Dial Home Date", column_type="Dimension[SYR Last Dial Home Date]", output_type="None" }, { name="Maintained By Group", column_type="Dimension[Maintained By Group]", output_type="None" }, { name="PS Flag", column_type="Dimension[PS Flag]", output_type="None" }, { name="Connect Home Refusal Reason", column_type="Dimension[Connect Home Refusal Reason]", output_type="None", col_width=177 }, { name="Cust Name", column_type="Dimension[Cust Name]", output_type="None" }, { name="Sales Order Channel Type", column_type="Dimension[Sales Order Channel Type]", output_type="None" }, { name="Sales Order Type", column_type="Dimension[Sales Order Type]", output_type="None" }, { name="Part Model Key", column_type="Dimension[Part Model Key]", output_type="None" }, { name="Ship Date", column_type="Dimension[Ship Date]", output_type="None" }, { name="Model Number", column_type="Dimension[Model Number]", output_type="None" }, { name="Item Description", column_type="Dimension[Item Description]", output_type="None" }, { name="Customer Classification", column_type="Dimension[Customer Classification]", output_type="None" }, { name="CS Customer Name", column_type="Dimension[CS Customer Name]", output_type="None" }, { name="Install At Customer Number", column_type="Dimension[Install At Customer Number]", output_type="None" }, { name="Install at Country Name", column_type="Dimension[Install at Country Name]", output_type="None" }, { name="TLA Serial Number", column_type="Dimension[TLA Serial Number]", output_type="None" }, { name="Product Version", column_type="Dimension[Product Version]", output_type="None" }, { name="Avalanche Flag", column_type="Dimension[Avalanche Flag]", output_type="None" }, { name="Product Family", column_type="Dimension[Product Family]", output_type="None" }, { name="Project Number", column_type="Dimension[Project Number]", output_type="None" }, { name="PROJECT_STATUS", column_type="Dimension[PROJECT_STATUS]", output_type="None" } }, Available_Columns={ "Total TSS installs", "TSS Valid Connectivity Records", "% TSS Connectivity Record", "TSS Not Applicable", "TSS Customer Refusals", "% TSS Refusals", "TSS Eligible for Physical Connectivity", "TSS Boxes with Physical Connectivty", "% TSS Physical Connectivity", "Total Installs", "All Boxes with Valid Connectivty Record", "% All Connectivity Record", "Overall Refusals", "Overall Refusals %", "All Eligible for Physical Connectivty", "Boxes with Physical Connectivity", "% All with Physical Conectivity" }, Remaining_columns={ { name="Total Installs", column_type="Calc[Total Installs]", output_type="Number", format_string="." }, { name="All Boxes with Valid Connectivty Record", column_type="Calc[All Boxes with Valid Connectivty Record]", output_type="Number", format_string="." }, { name="% All Connectivity Record", column_type="Calc[% All Connectivity Record]", output_type="Number" }, { name="Overall Refusals", column_type="Calc[Overall Refusals]", output_type="Number", format_string="." }, { name="Overall Refusals %", column_type="Calc[Overall Refusals %]", output_type="Number" }, { name="All Eligible for Physical Connectivty", column_type="Calc[All Eligible for Physical Connectivty]", output_type="Number" }, { name="Boxes with Physical Connectivity", column_type="Calc[Boxes with Physical Connectivity]", output_type="Number" }, { name="% All with Physical Conectivity", column_type="Calc[% All with Physical Conectivity]", output_type="Number" } }, calcs={ { name="Total TSS installs", definition="Total[Total TSS installs]", ts_flag="Not TS Calc" }, { name="TSS Valid Connectivity Records", definition="Total[PS Boxes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="% TSS Connectivity Record", definition="Total[PS Boxes w/ valid connectivity record (1=yes)] /Total[Total TSS installs]", ts_flag="Not TS Calc" }, { name="TSS Not Applicable", definition="Total[Bozes w/ valid connectivity record (1=yes)]-Total[Boxes Eligible (1=yes)]-Total[TSS Refusals]", ts_flag="Not TS Calc" }, { name="TSS Customer Refusals", definition="Total[TSS Refusals]", ts_flag="Not TS Calc" }, { name="% TSS Refusals", definition="Total[TSS Refusals]/Total[PS Boxes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="TSS Eligible for Physical Connectivity", definition="Total[TSS Eligible]-Total[Exception]", ts_flag="Not TS Calc" }, { name="TSS Boxes with Physical Connectivty", definition="Total[PS Physical Connectivity] - Total[PS Physical Connectivity, SymmConnect Enabled=\"Capable not enabled\"]", ts_flag="Not TS Calc" }, { name="% TSS Physical Connectivity", definition="Total[Boxes w/ phys conn]/Total[Boxes Eligible (1=yes)]", ts_flag="Not TS Calc" }, { name="Total Installs", definition="Total[Total Installs]", ts_flag="Not TS Calc" }, { name="All Boxes with Valid Connectivty Record", definition="Total[Bozes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="% All Connectivity Record", definition="Total[Bozes w/ valid connectivity record (1=yes)]/Total[Total Installs]", ts_flag="Not TS Calc" }, { name="Overall Refusals", definition="Total[Overall Refusals]", ts_flag="Not TS Calc" }, { name="Overall Refusals %", definition="Total[Overall Refusals]/Total[Bozes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="All Eligible for Physical Connectivty", definition="Total[Boxes Eligible (1=yes)]-Total[Exception]", ts_flag="Not TS Calc" }, { name="Boxes with Physical Connectivity", definition="Total[Boxes w/ phys conn]-Total[Boxes w/ phys conn,SymmConnect Enabled=\"Capable not enabled\"]", ts_flag="Not TS Calc" }, { name="% All with Physical Conectivity", definition="Total[Boxes w/ phys conn]/Total[Boxes Eligible (1=yes)]", ts_flag="Not TS Calc" } }, merge_type="consolidate", merge_dbs={ { dbname="connectivityallproducts.mdl", diveline_dbname="/DI_PSREPORTING/connectivityallproducts.mdl" } }, skip_constant_columns="FALSE", categories={ { name="Geography", dimensions={ "Theater", "Division", "Region", "Install at Country Name" } }, { name="Mappings and Flags", dimensions={ "Connect Home Type", "Connect In Type", "SymmConnect Enabled", "Connect Home Refusal Reason", "Sales Order Channel Type", "Maintained By Group", "Customer Installable", "PS Flag", "Top Level Flag", "Avalanche Flag" } }, { name="Product Information", dimensions={ "Product Family", "Product Item Family", "Product Version", "Item Description" } }, { name="Sales Order Info", dimensions={ "Sales Order Deal Number", "Sales Order Number", "Sales Order Type" } }, { name="Dates", dimensions={ "Item Install Date", "Ship Date", "SYR Last Dial Home Date" } }, { name="Details", dimensions={ "Item Serial Number", "TLA Serial Number", "Part Model Key", "Model Number" } }, { name="Customer Infor", dimensions={ "CS Customer Name", "Install At Customer Number", "Customer Classification", "Cust Name" } }, { name="Other Dimensions", dimensions={ "Model" } } }, Maintain_Category_Order="FALSE", popup_info="false" } } };

Read the article
Can I use a single DateTime field on the Entity Framework model side when the value is stored in a set of Int fields in the actual database?

- by Ivan

The actual table in the database has separate integer fields for storing year, month, day, hour and minute values (all in UTC) (seconds and milliseconds are irrelevant for my task and considered equal to zero). Needless to say it would be of great convenience to have just one field of DateTime type on the application side and hide all the conversion under the cover of the Entity Framework model code. Any directions on how to do that? I am not very experienced with Entity Framework yet.

Read the article

< Previous Page | 324 325 326 327 328 329 330 331 332 333 334 335 | Next Page >