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• Exceptions over remote methods

  - by Andrei Vajna II

  What are the best practices for exceptions over remote methods? I'm sure that you need to handle all exceptions at the level of a remote method implementation, because you need to log it on the server side. But what should you do afterwards? Should you wrap the exception in a RemoteException (java) and throw it to the client? This would mean that the client would have to import all exceptions that could be thrown. Would it be better to throw a new custom exception with fewer details? Because the client won't need to know all the details of what went wrong. What should you log on the client? I've even heard of using return codes(for efficiency maybe?) to tell the caller about what happened. The important thing to keep in mind, is that the client must be informed of what went wrong. A generic answer of "Something failed" or no notification at all is unacceptable. And what about runtime (unchecked) exceptions?

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• Revision Control System Recommendations

  - by Jordan Arsenault

  I've reached a point in my independent development work where I would like to start using Subversion techniques. Up to now, I've been simply making backups by exporting my current database, and zipping them together with my PHP project files. I've read some articles online and watched a video with Linus Torvalds - the general verdict seems to be that Git is in and old CVS techniques are out. I'm not currently operating under Linux, I do all PHP work out of Windows - Eclipse. Due to the fact that Eclipse runs on JVM, jumping into Linux - Eclipse will be more or less transparent - file system aside. What I would like to accomplish is being able to keep a constant revision history - But I want this to be almost entirely transparent. Also, I work in an MVC framework, and I would like to be able to release my views to Designers, and have them work from within the revision control system too. Will Egit accomplish what I need? Or is it too much overhead for a one-man workforce? What do you recommend I use so that I can keep a revision history? I also require the service to be free! Thank you all - StackOverflow ftw!

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• Why use Intent.URI_INTENT_SCHEME

  - by hks

  while reading Android docs about Widgets I stumbled upon this piece of code whose purpose is to launch a service for retrieving a factory for StackView items. // Set up the intent that starts the StackViewService, which will // provide the views for this collection. Intent intent = new Intent(context, StackWidgetService.class); // Add the app widget ID to the intent extras. intent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_ID, appWidgetIds[i]); intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME))); // Instantiate the RemoteViews object for the App Widget layout. RemoteViews rv = new RemoteViews(context.getPackageName(), R.layout.widget_layout); // Set up the RemoteViews object to use a RemoteViews adapter. // This adapter connects // to a RemoteViewsService through the specified intent. // This is how you populate the data. rv.setRemoteAdapter(appWidgetIds[i], R.id.stack_view, intent); You can find it here I have a problem understanding why do you need to call intent.setData(Uri.parse(intent.toUri(Intent.URI_INTENT_SCHEME))); I understand that it gives URI a prefix intent://, but is it necessary here?

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• My program is spending most of its time in objc_msgSend. Does that mean that Objective-C has bad per

  - by Paperflyer

  Hello Stackoverflow. I have written an application that has a number of custom views and generally draws a lot of lines and bitmaps. Since performance is somewhat critical for the application, I spent a good amount of time optimizing draw performance. Now, activity monitor tells me that my application is usually using about 12% CPU and Instrument (the profiler) says that a whopping 10% CPU is spent in objc_msgSend (mostly in drawing related system calls). On the one hand, I am glad about this since it means that my drawing is about as fast as it gets and my optimizations where a huge success. On the other hand, it seems to imply that the only thing that is still using my CPU is the Objective-C overhead for messages (objc_msgSend). Hence, that if I had written the application in, say, Carbon, its performance would be drastically better. Now I am tempted to conclude that Objective-C is a language with bad performance, even though Cocoa seems to be awfully efficient since it can apparently draw faster than Objective-C can send messages. So, is Objective-C really a language with bad performance? What do you think about that?

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• How do I place widgets above and below a listview?

  - by Jay Askren

  I have a list view and want to put stuff both above(on the y axis) and below(y axis) it including images, text views, and a row of buttons. Below is a simplified version of what I am creating. Unfortunately the list covers(i.e. above on the z axis) the header so the header text is not visible instead of being underneath (on the y axis) <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="wrap_content"> <TextView android:id="@+id/footer" android:text="footer" android:layout_height="wrap_content" android:layout_width="fill_parent" android:layout_alignParentBottom="true" /> <ListView android:id="@+id/list_view" android:layout_height="fill_parent" android:layout_width="fill_parent" android:layout_above="@id/footer" android:background="#ff9999ff"/> <TextView android:id="@+id/header" android:text="header" android:layout_height="wrap_content" android:layout_width="fill_parent" android:layout_alignParentTop="true" android:layout_above="@id/list_view" android:baselineAlignBottom="false" /> </RelativeLayout> Here is the corresponding Activity class: public class SampleListActivity extends Activity { @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.list_activity); } }

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• c# threading and getting COM port of attached phone

  - by I__

  i have the following code: using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Threading; namespace WindowsFormsApplication1 { public partial class Form1 : Form { public Form1() { InitializeComponent(); } public class ThreadWork { public static void DoWork() { } } private void Form1_Load(object sender, EventArgs e) { ThreadStart myThreadDelegate = new ThreadStart(ThreadWork.DoWork); Thread myThread = new Thread(myThreadDelegate); myThread.Start(); // Begin communications serialPort1.Open(); serialPort1.Write("AT+CMGF=1\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CNMI=2,2\r\n"); //Thread.Sleep(500); serialPort1.Write("AT+CSCA=\"+4790002100\"\r\n"); //Thread.Sleep(500); } private void serialPort1_DataReceived_1(object sender, System.IO.Ports.SerialDataReceivedEventArgs e) { string response = serialPort1.ReadLine(); this.BeginInvoke(new MethodInvoker(() => textBox1.AppendText(response + "\r\n"))); } } } what i am trying to do is send AT COMMANDS to my phone which is attached to the computer through USB how do i know how to configure the properties of the serial port? (like which COM is the phone on [it's attached through USB], what about baudrate and databits?) when i run the program nothing really happens, i would like to send AT COMMANDS to my phone and the textbox is there to receive the response from my phone this is my first time using threads. am i using them correctly? what is the purpose of it in the current example? is it to just have a delay between send a response? what am i doing wrong?

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• What is the appropriate granularity in building a ViewModel?

  - by JasCav

  I am working on a new project, and, after seeing some of the difficulties of previous projects that didn't provide enough separation of view from their models (specifically using MVC - the models and views began to bleed into each other a bit), I wanted to use MVVM. I understand the basic concept, and I'm excited to start using it. However, one thing that escapes me a bit - what data should be contained in the ViewModel? For example, if I am creating a ViewModel that will encompass two pieces of data so they can be edited in a form, do I capture it like this: public PersonAddressViewModel { public Person Person { get; set; } public Address Address { get; set; } } or like this: public PersonAddressViewModel { public string FirstName { get; set; } public string LastName { get; set; } public string StreetName { get; set; } // ...etc } To me, the first feels more correct for what we're attempting to do. If we were doing more fine grain forms (maybe all we were capturing was FirstName, LastName, and StreetAddress) then it might make more sense to go down to that level. But, I feel like the first is correct since we're capturing ALL Person data in the form and ALL Address data. It seems like it doesn't make sense (and a lot of extra work) to split things apart like that. Appreciate any insight.

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• Keeping user data persistent after validates_presence_of

  - by mathee

  I'm designing a question-and-answer Ruby on Rails application. After a user logs in, you can see a list of questions posed by other users. I have a link next to each of the questions to /answers/new?question_id=someNumber. That links to a page that displays the question (to remind the "answerer") above a standard form for submitting your answer. In order to display the question, I call @question = Question.find_by_id(params[:question_id]) and reference @question in the Haml view file: Question details %h2 #{h @question.title} #{h @question.description} %br/ %br/ %h1 Your answer - form_for(@answer) do |f| = f.error_messages %p = f.label :description, "Enter your response here" %br = f.text_area :description = f.hidden_field "question", :value => @question.id %p = f.submit 'Answer' The problem is that if I check validates_presence_of :description in Answer.rb, then I lose question_id if the user did not input anything into the description field when the page reloads, so I can't re-display the question for which the user is answering. How should I fix this? Is there a better way of storing the question the user is trying to answer so that I can display it above the form for entering a new answer (and perhaps in other views in the future)? If you need to see more code, please let me know.

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• Why Is the sender type null when dealing with events

  - by ChloeRadshaw

  From C# Via CLR: Note A lot of people wonder why the event pattern requires the sender parameter to always be of type Object After all, since the MailManager will be the only type raising an event with a NewMail EventArgs object, it makes more sense for the callback method to be prototyped like this: void MethodName(Mai l Manager sender, NewMail EventArgs e); The pattern requires the sender parameter to be of type Object mostly because of inheritance What if Mai lManager were used as a base class for SmtpMailManager? In this case, the callback method should have the sender parameter prototyped as SmtpMailManager instead of Mail Manager, but this can’t happen because SmtpMai lManager just inherited the NewMai l event So the code that was expecting SmtpMail Manager to raise the event must still have to cast the sender argument to SmtpMailManager In other words, the cast is still required, so the sender parameter might as well be typed as Obj ect The next reason for typing the sender parameter as Obj ect is just fexibility It allows the delegate to be used by multiple types that offer an event that passes a NewMail EventArgs object For example, a PopMai lManager class could use the delegate even if this class were not derived from Mail Manager I just simply cannot understand why the sender is an object - Why can it not be generified? so most of the time we do not need to do generic casts

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• Mono Develop 2.4.1 + linq error.

  - by Nev_Rahd

  I just started to learn Mono Develop Installed Mono Develop 2.4.1 and trial version of Mono Touch. my Code: using System; using System.Xml.Linq; using System.Collections.Generic; namespace RSSReader { public static class RSSRepository { public static IList<FeedItem> GetFeeds(string url) { XDocument rssFeed = XDocument.Load(url); Console.Write(rssFeed.ToString()); var feeds = new List<FeedItem>(); try { var query = from item in rssFeed.Descendants("item") select new FeedItem { Title = item.Element("title").Value, Published = DateTime.Parse(item.Element("pubDate").Value), Url = item.Element("link").Value }; feeds = query.ToList(); } catch (Exception ex){ Console.WriteLine(ex.Message); } return feeds; } } } This is throwing an error: An implementation of 'select' query expression pattern could not be found. Are you missing 'System.linq' using directive or 'System.Core.dll' assembly reference? I got both references to System.Xml.Linq and System.Core What am i missing ?

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• iPhone dev: UIBarButtonItem or title not showing up in NavigationBar

  - by IceMan85

  Hello everyone, here my problem. I have a NavigationBar at the top, a TabBar at the bottom and a TableView at the center of the screen. Very normal situation. I set it all up in IB and I have set this in the app delegate : ExpensesListNavController *expensesListNavController; This in order to be able to add new views to the stack. I need to have 3 levels: - list of items in a TableView - OK - firstLevel: once pressed one cell a view is added to the stack - OK - second level: one pressed the "modify" button on the navBar on the firstLevel I want to show a new view that can be customized by the user. My Problem is coming when trying to add the "Modify" button in the "firstLevelView". Here-below my code -(IBAction) modify:(id)sender { if (editableDetailViewController == nil) { editableDetailViewController = [[editableDetailViewController alloc] init]; } editableDetailViewController.expense = expense; [appDelegate.expensesListNavController pushViewController:editableDetailViewController animated:YES]; editableDetailViewController = nil; } // Implement viewDidLoad to do additional setup after loading the view, typically from a nib. - (void)viewDidLoad { [super viewDidLoad]; appDelegate = [[UIApplication sharedApplication] delegate]; UIBarButtonItem *modifyButton = [[UIBarButtonItem alloc] initWithTitle:@"Modify" style:UIBarButtonItemStylePlain target:self action:@selector(modify:)]; appDelegate.expensesListNavController.navigationItem.rightBarButtonItem = modifyButton; appDelegate.expensesListNavController.navigationItem.title = @"Titoloooo"; NSLog(@"NavBar button has just been set !!"); [modifyButton release]; Nothing is being showed, neither title nor the button. Do you have any idea of what is happening ?? I really cannot figure out !!! Thanks a lot in advance, AM

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• Devise password reset issue (new_user?)

  - by rabid_zombie

  When a user's email is inputted into the forgot password form and submitted, I am receiving an error saying login can't be blank. I looked around devise.en.yml for this error message, but can't seem to find it anywhere. Here is my views/devise/passwords/new.html.haml: %div.registration_page %h2 Forgot your password? = form_for(resource, :as => resource_name, :url => user_password_path, :html => { :method => :post, :id => 'forgot_pw_form', :class => 'forgot_pw' }) do |f| %div = f.email_field :email, :placeholder => 'Email', :autofocus => true, :autocomplete => 'off' %div.email_error.error %input.btn.btn-success{:type => 'submit', :value => 'Send Instructions'} = render "devise/shared/links" The form is posting to users/password like it should, but I noticed that my forgot password form attaches class = 'new_user'. Here is what my form displays: <form accept-charset='UTF-8' action='/users/password' class='new_user' id='forgot_pw_form' method='post' novalidate='novalidate'></form> My routes for devise (I have custom sessions and registrations controllers): devise_for :users, :controllers => {:sessions => 'sessions', :registrations => 'registrations'} How can I setup devise's forgot password functionality? Why am I receiving this error message and why is that class being added there? I've tried: Adding my own passwords controller and adding new routes for my custom controller. Same error Adding my own class and id to the form. This successfully changes the id and class of the form, but reverts back to class and id of new_user Thanks.

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• I would like to flip my app's splash screen - how can I mimic the flipside controller's animation?

  - by Andy

  I've finally gotten a working "alpha" version of my first app installed and (mostly) working on my iPhone 3G. So excited I came into the house and danced a little jig while my wife rolled her eyes at me. Don't care - totally stoked that I figured it out on my own (with lots of help here - thanks again, guys). I've never really dabbled with or cared about animation; I'm more into utility-type apps. However, I've decided that I'd like to animate my app's opening image / default.png / splash screen similar to the flipside view controller animation - where the image spins from a view on the front to a different view on the back. I've found code for animating between views using the flipside animation, but how would I go about animating from a static *.png image to my navigation-based table view? I'm just not even sure where to start with this one - literally the first time I've ever even searched for anything graphics-related in the documentation. Any help will be appreciated. As usual, thanks in advance!

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• How do I use cookies to store users' recent site history(PHP)?

  - by ggfan

  I decided to make a recent view box that allows users to see what links they clicked on before. Whenever they click on a posting, the posting's id gets stored in a cookie and displays it in the recent view box. In my ad.php, I have a definerecentview function that stores the posting's id (so I can call it later when trying to get the posting's information such as title, price from the database) in a cookie. How do I create a cookie array for this? **EXAMPLE:** user clicks on ad.php?posting_id='200' //this is in the ad.php function definerecentview() { $posting_id=$_GET['posting_id']; //this adds 30 days to the current time $Month = 2592000 + time(); $i=1; if (isset($posting_id)){ //lost here for($i=1,$i< ???,$i++){ setcookie("recentviewitem[$i]", $posting_id, $Month); } } } function displayrecentviews() { echo "<div class='recentviews'>"; echo "Recent Views"; if (isset($_COOKIE['recentviewitem'])) { foreach ($_COOKIE['recentviewitem'] as $name => $value) { echo "$name : $value <br />\n"; //right now just shows the posting_id } } echo "</div>"; } How do I use a for loop or foreach loop to make it that whenever a user clicks on an ad, it makes an array in the cookie? So it would be like.. 1. clicks on ad.php?posting_id=200 --- setcookie("recentviewitem[1]",200,$month); 2. clicks on ad.php?posting_id=201 --- setcookie("recentviewitem[2]",201,$month); 3. clicks on ad.php?posting_id=202 --- setcookie("recentviewitem[3]",202,$month); Then in the displayrecentitem function, I just echo however many cookies were set? I'm just totally lost in creating a for loop that sets the cookies. any help would be appreciated

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• DeleteOnSubmit doesnt exist?

  - by Anders Metnik

  using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; Thats my namespaces.. i was looking for System.Data.Linq; but it doesnt seem to be anywhere, and i guess that is what have been moved to System.Linq, since i have access to most other things in Linq. EDIT: found System.Data:Linq, no difference Here is my method: public void deleteStudienummer(int studienummer) { dbcontent = new DBEntities(); var dQry = from members in dbcontent.Medlemmer where members.Studienummer == studienummer select members; foreach (var member in dQry) { dbcontent.*** } dbcontent.AcceptAllChanges(); Console.WriteLine("delete member should have occured"); } The * was supposed to be DeleteOnSubmit, but i only have DeleteDatabase and DeleteObject, i tried with object but it doesnt work.. Have also tried dbcontent.Medlemmer.* but still not present. And AcceptAllChanges() was supposed to be .submitChanges() but that wasnt present either.

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• Pass List of models to controller ASP.NET MVC 5

  - by user3697231

  I have a view where user can enter some data. But problem is this: Let's say you have 3 text box on view. Every time user can fill multiple times this 3 text boxes. To clarify, let's say user fills this 3 text boxes and press button which adds on form again these 3 text boxes. Now when user clicks submit this form is sent to controller, but how do I sent List of models as parameter. My architecture for this problem is something like this: MyModel public int ID { get;set; } public string Something { get; set; } /*This three textboxes can user set multiple times*/ /*Perhaps i Can create new model with these properties and then /*put List of that model as property here, but how to fill that list inside view ??*/ public string TextBoxOneValue { get; set; } public string TextBoxTwoValue { get; set; } public string TextBoxThreeValue { get; set; } Now, i was thinking that i Create PartialView with this 3 text boxes, and then when user clicks button on view another PartialView is loaded. And now, let's say I have Two partial views loaded, and user clicks submit, how that I pass list with values of these 3 text boxes to controller ??

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• Looking for an email template engine for end-users ...

  - by RizwanK

  We have a number of customers that we have to send monthly invoices too. Right now, I'm managing a codebase that does SQL queries against our customer database and billing database and places that data into emails - and sends it. I grow weary of maintaining this every time we want to include a new promotion or change our customer service phone numbers. So, I'm looking for a replacement to move more of this into the hands of those requesting the changes. In my ideal world, I need : A WYSIWYG (man, does anyone even say that anymore?) email editor that generates templates based upon the output from a Database Query. The ability to drag and drop various fields from the database query into the email template. Display of sample email results with the database query. Web application, preferably not requiring IIS. Involve as little code as possible for the end-user, but allow basic functionality (i.e. arrays/for loops) Either comes with it's own email delivery engine, or writes output in a way that I can easily write a Python script to deliver the email. Support for generic Database Connectors. (I need MSSQL and MySQL) F/OSS So ... can anyone suggest a project like this, or some tools that'd be useful for rolling my own? (My current alternative idea is using something like ERB or Tenjin, having them write the code, but not having live-preview for the editor would suck...)

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• LINQ to SQL - Lightweight O/RM?

  - by CoffeeAddict

  I've heard from some that LINQ to SQL is good for lightweight apps. But then I see LINQ to SQL being used for Stackoverflow, and a bunch of other .coms I know (from interviewing with them). Ok, so is this true? for an e-commerce site that's bringing in millions and you're typically only doing basic CRUDs most the time with the exception of an occasional stored proc for something more complex, is LINQ to SQL complete enough and performance-wise good enough or able to be tweaked enough to run happily on an e-commerce site? I've heard that you just need to tweak performance on the DB side when using LINQ to SQL for a better approach. So there are really 2 questions here: 1) Meaning/scope/definition of a "Lightweight" O/RM solution: What the heck does "lightweight" mean when people say LINQ to SQL is a "lightweight O/RM" and is that true??? If this is so lightweight then why do I see a bunch of huge .coms using it? Is it good enough to run major .coms (obviously it looks like it is) and what determines what the context of "lightweight" is...it's such a generic statement. 2) Performance: I'm working on my own .com and researching different O/RMs. I'm not really looking at the Entity Framework (yet), just want to figure out the LINQ to SQL basics here and determine if it will be efficient enough for me. The problem I think is you can't tweak or control the SQL it generates...

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• PHP: Opening/closing tags & performance?

  - by Tom

  Hi, This may be a silly question, but as someone relatively new to PHP, I'm wondering if there are any performance-related issues to frequently opening and closing PHP tags in HTML template code, and if so, what might be best practices in terms of working with php tags? My question is not about the importance/correctness of closing tags, or about which type of code is more readable than another, but rather about how the document gets parsed/executed and what impact it might have on performance. To illustrate, consider the following two extremes: Mixing PHP and HTML tags: <?php echo '<tr> <td>'.$variable1.'</td> <td>'.$variable2.'</td> <td>'.$variable3.'</td> <td>'.$variable4.'</td> <td>'.$variable5.'</td> </tr>' ?> // PHP tag opened once Separating PHP and HTML tags: <tr> <td><?php echo $variable1 ?></td> <td><?php echo $variable2 ?></td> <td><?php echo $variable3 ?></td> <td><?php echo $variable4 ?></td> <td><?php echo $variable5 ?></td> </tr> // PHP tag opened five times Would be interested in hearing some views on this, even if it's just to hear that it makes no difference. Thanks.

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• Unit Testing Interfaces in Python

  - by Nicholas Mancuso

  I am currently learning python in preperation for a class over the summer and have gotten started by implementing different types of heaps and priority based data structures. I began to write a unit test suite for the project but ran into difficulties into creating a generic unit test that only tests the interface and is oblivious of the actual implementation. I am wondering if it is possible to do something like this.. suite = HeapTestSuite(BinaryHeap()) suite.run() suite = HeapTestSuite(BinomialHeap()) suite.run() What I am currently doing just feels... wrong (multiple inheritance? ACK!).. class TestHeap: def reset_heap(self): self.heap = None def test_insert(self): self.reset_heap() #test that insert doesnt throw an exception... for x in self.inseq: self.heap.insert(x) def test_delete(self): #assert we get the first value we put in self.reset_heap() self.heap.insert(5) self.assertEquals(5, self.heap.delete_min()) #harder test. put in sequence in and check that it comes out right self.reset_heap() for x in self.inseq: self.heap.insert(x) for x in xrange(len(self.inseq)): val = self.heap.delete_min() self.assertEquals(val, x) class BinaryHeapTest(TestHeap, unittest.TestCase): def setUp(self): self.inseq = range(99, -1, -1) self.heap = BinaryHeap() def reset_heap(self): self.heap = BinaryHeap() class BinomialHeapTest(TestHeap, unittest.TestCase): def setUp(self): self.inseq = range(99, -1, -1) self.heap = BinomialHeap() def reset_heap(self): self.heap = BinomialHeap() if __name__ == '__main__': unittest.main()

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• Typical Search, Result and Detail Workflow Staying Within an Android Tab

  - by Justin

  So, I've been banging my head looking for a good solution for a few days and am stuck. I have a search screen (Activity) in a tab, and after the user enters a value and clicks "search" I would like the results to come back in that same tab, and then if an item from the results is selected, to show more detailed results, in that same tab. I have it all working now in separate activities, and even the first step working in a tab, but as soon as I call the activity to process he search results... i.e. startActivity(i); for the results Activity, the results displayed are not in the tab! I am having a very difficult time getting this flow to work all under a tab. Any thoughts on how to make this happen? I keep hearing that Android views should be used instead of activities, but am I then to assume that all the logic I have right now for 3 activity needs to go inside 1 activity and then I need to handle setting the content and state for each of these cases? Plus, won't the history stack not work as pressing the back button will take the user out of the application, instead of taking them from say the search result to the search screen, or the details to the search results, etc. This seems like a mess. Can anyone show a more complex example of tabs or how one might have a simple search, result and detail workflow staying in a tab? I have seen a few questions on this concept of keeping activities "within a tab", but no good resolution. Please help.

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• Using boost::random to select from an std::list where elements are being removed

  - by user144182

  See this related question on more generic use of the Boost Random library. My questions involves selecting a random element from an std::list, doing some operation, which could potentally include removing the element from the list, and then choosing another random element, until some condition is satisfied. The boost code and for loop look roughly like this: // create and insert elements into list std::list<MyClass> myList; //[...] // select uniformly from list indices boost::uniform_int<> indices( 0, myList.size()-1 ); boost::variate_generator< boost::mt19937, boost::uniform_int<> > selectIndex(boost::mt19937(), indices); for( int i = 0; i <= maxOperations; ++i ) { int index = selectIndex(); MyClass & mc = myList.begin() + index; // do operations with mc, potentially removing it from myList //[...] } My problem is as soon as the operations that are performed on an element result in the removal of an element, the variate_generator has the potential to select an invalid index in the list. I don't think it makes sense to completely recreate the variate_generator each time, especially if I seed it with time(0).

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• How do I create a polymorphic model with a collection_select?

  - by muxe

  This are my models: class Speaker < ActiveRecord::Base belongs_to :session, :foreign_key => :session_id, :class_name => :Session belongs_to :speakable, :polymorphic => true end class Session < ActiveRecord::Base has_many :speakers accepts_nested_attributes_for :speakers end class Person < ActiveRecord::Base has_many :speakers, :as => :speakable end class Company < ActiveRecord::Base has_many :speakers, :as => :speakable end What I want to do now is something like this: app/views/sessions/edit.html.erb <% f.fields_for :speakers do |sf| %> <p> <%= sf.label :speaker %><br /> <%= sf.collection_select :speakable, Company.all + Person.all, :id, :full_name %> </p> <% end %> But it is not working because of the polymorphic assignment. How do I approach this problem? EDIT: The Error is: undefined method `base_class' for String:Class with params being: "speaker"=>{"speakable"=>"1063885469", "session_id"=>"1007692731"} The value passed to speakable is the id of the Speaker/Company. Yes, this is the value I specified the collection_select to return, but how can I manage to supply both values (speakable_id and speakable_type) ?

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• Reflection and Generics get value of property

  - by GigaPr

  Hi i am trying to implement a generic method which allows to output csv file public static void WriteToCsv<T>(List<T> list) where T : new() { const string attachment = "attachment; filename=PersonList.csv"; HttpContext.Current.Response.Clear(); HttpContext.Current.Response.ClearHeaders(); HttpContext.Current.Response.ClearContent(); HttpContext.Current.Response.AddHeader("content-disposition", attachment); HttpContext.Current.Response.ContentType = "text/csv"; HttpContext.Current.Response.AddHeader("Pragma", "public"); bool isFirstRow = true; foreach (T item in list) { //Get public properties PropertyInfo[] propertyInfo = item.GetType().GetProperties(); while (isFirstRow) { WriteColumnName(propertyInfo); isFirstRow = false; } Type type = typeof (T); StringBuilder stringBuilder = new StringBuilder(); foreach (PropertyInfo info in propertyInfo) { //string value ???? I am trying to get the value of the property info for the item object } HttpContext.Current.Response.Write(stringBuilder.ToString()); HttpContext.Current.Response.Write(Environment.NewLine); } HttpContext.Current.Response.End(); } but I am not able to get the value of the object's property Any suggestion? Thanks

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• Jquery passing an HTML element into a function

  - by christian

  I have an HTML form where I am going to copy values from a series of input fields to some spans/headings as the user populates the input fields. I am able to get this working using the following code: $('#source').keyup(function(){ if($("#source").val().length == 0){ $("#destinationTitle").text('Sample Title'); }else{ $("#destinationTitle").text($("#source").val()); } }); In the above scenario the html is something like: Sample Title Basically, as the users fills out the source box, the text of the is changed to the value of the source input. If nothing is input in, or the user deletes the values typed into the box some default text is placed in the instead. Pretty straightforward. However, since I need to make this work for many different fields, it makes sense to turn this into a generic function and then bind that function to each 's onkeyup() event. But I am having some trouble with this. My implementation: function doStuff(source,target,defaultValue) { if($(source).val().length == 0){ $(target).text(defaultValue); }else{ $(target).text($(source).val()); } } which is called as follows: $('#source').keyup(function() { doStuff(this, '"#destinationTitle"', 'SampleTitle'); }); What I can't figure out is how to pass the second parameter, the name of the destination html element into the function. I have no problem passing in the element I'm binding to via "this", but can't figure out the destination element syntax. Any help would be appreciated - many thanks!

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