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• Core Data and BOOL setup

  - by John Valen

  I am working on an app that uses Core Data as its backend for managing SQLite records. I have everything working with strings and numbers, but have just tried adding BOOL fields and can't seem to get things to work. In the .xcdatamodel, I have added a field to my object called isCurrentlyForSale which is not Optional, not Transient, and not Indexed. The attribute's type is set to Boolean with default value NO. When I created the class files from the data model, the boilerplate code added for this property in the .h header was: @property (nonatomic, retain) NSNumber * isCurrentlyForSale; along with the @dynamic isCurrentlyForSale; in the .m implementation file. I've always worked with booleans as simple BOOLs. I've read that I could use NSNumber's numberWithBool and boolValue methods, but this seems like an aweful lot of extra code for something so simple. Can the @property in the header be changed to a simple BOOL? If so is there anything to watch out for? Thanks -John

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• Is this an UITableView -beginUpdates documentation error?

  - by mystify

  I can't wrap my head around what they tried to say here in the docs for -beginUpdate: Call this method if you want subsequent insertions, deletion, and selection operations (for example, cellForRowAtIndexPath: and indexPathsForVisibleRows) to be animated simultaneously. Let's see... cellForRowAtIndexPath: and indexPathsForVisibleRows are both GETTER methods. They do not update anything and do not change anything. So why should I call -beginUpdates before calling these? And what's animated regarding these? Well, nothing, huh? Just want to make sure this is really an error in the docs and I didn't miss something.

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• Add a listener inside or outside get method

  - by James P.

  I'm learning Swing and have composed an interface using a series of get methods to add components. Is it a good practise to add a Listener inside a get method as follows? I'd like to make things as decoupled as possible. private JButton getConnectButton() { if (connectButton == null) { connectButton = new JButton(); connectButton.setText("Connect"); connectButton.setSize(new Dimension(81, 16)); connectButton.setLocation(new Point(410, 5)); connectButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { // actionPerformed code goes here } }); } return connectButton; }

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• Select a data template by item type programatically in WPF

  - by Michael Stoll

  Hi all, unfortunately the WPF ToolbarTray does not support binding to a collection of ToolbarViewModels (Correct me, if I'm wrong). Thus I want to create the Toolbars programmatically. So there are two tasks, which I don't know how to do: Select the data template based on the item type. Instantiate the data template as toolbar Both should do the same as WPF does, when we use ItemsControl with an enumerable content and empty template. I used reflector to anaylse what WPF does. Task 1 is done by FrameworkElement.FindTemplateResourceInternal, but this is internal, and I couldn't find any public methods to acomplish the task. Of course one could enumerate all resources and match the data template data type property, but this seems sub-optimal. Who know's how to acomplish these tasks?

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• does a switch idiom make sense in this case?

  - by the ungoverned

  I'm writing a parser/handler for a network protocol; the protocol is predefined and I am writing an adapter, in python. In the process of decoding the incoming messages, I've been considering using the idiom I've seen suggested elsewhere for "switch" in python: use a hash table whose keys are the field you want to match on (a string in this case) and whose values are callable expressions: self.switchTab = { 'N': self.handleN, 'M': self.handleM, ... } Where self.handleN, etc., are methods on the current class. The actual switch looks like this: self.switchTab[selector]() According to some profiling I've done with cProfile (and Python 2.5.2) this is actually a little bit faster than a chain of if..elif... statements. My question is, do folks think this is a reasonable choice? I can't imagine that re-framing this in terms of objects and polymorphism would be as fast, and I think the code looks reasonably clear to a reader.

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• Looking for a C# code parser

  - by Blindy

  I'm looking for a set of classes (preferably in the .net framework) that will parse C# code and return a list of functions with parameters, classes with their methods, properties etc. Ideally it would provide all that's needed to build my own intellisense. I have a feeling something like this should be in the .net framework, given all the reflection stuff they offer, but if not then an open source alternative is good enough. What I'm trying to build is basically something like Snippet Compiler, but with a twist. I'm trying to figure out how to get the code dom first. I tried googling for this but I'm not sure what the correct term for this is so I came up empty.

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• Is it safe to call a function to intialize a class in a ctor list?

  - by Michael Dorgan

  I have Angle class that I want initialized to a random value. The Angle constructor can accept an int from a random() function. Is it safe to place this call in the ctor list: foo::foo() : Angle(random(0xFFFF)) {...} or do I have to do it in the body of the constructor? foo::foo() { Angle = Angle(random(0xFFFF)); ...} If it matters, the foo class is derived from another class and does have virtual methods. In addition, no exception handling is allowed in our app.

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• Handling auto-incrementing IDENTITY SQL Server fields with LINQ to SQL in C#

  - by Maxim Z.

  I'm building an ASP.NET MVC site that uses LINQ to SQL to connect to SQL Server, where I have a table that has an IDENTITY bigint primary key column that represents an ID. In one of my code methods, I need to create an object of that table to get its ID, which I will place into another object based on another table (FK-to-PK relationship). At what point is the IDENTITY column value generated and how can I obtain it from my code? Is the right approach to: Create the object that has the IDENTITY column Do an InsertOnSubmit() and SubmitChanges() to submit the object to the database table Get the value of the ID property of the object

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• How to keep the popup menu of a JComboBox open on populating it ?

  - by Stormshadow

  I have a JComboBox on my Panel. One of the popup menu items is 'More' and when I click that I fetch more menu items and add them to the existing list. After this, I wish to keep the popup menu open so that the user realizes that more items have been fetched however, the popup closes. The event handler code I am using is as follows public void actionPerformed(ActionEvent e) { if (e.getSource() == myCombo) { JComboBox selectedBox = (JComboBox) e.getSource(); String item = (String) selectedBox.getSelectedItem(); if (item.toLowerCase().equals("more")) { fetchItems(selectedBox); } selectedBox.showPopup(); selectedBox.setPopupVisible(true); } } private void fetchItems(JComboBox box) { box.removeAllItems(); /* code to fetch items and store them in the Set<String> items */ for (String s : items) { box.addItem(s); } } I do not understand why the showPopup() and setPopupVisible() methods are not functioning as expected.

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• What is wrong with my Basic Authentication in FireFox?

  - by Pure.Krome

  Hi folks, i'm trying to goto the following url :- http://user1:pass1@localhost:1234/api/users?format=xml nothing to complex. Notice how i've got the username/password in the url? this, i believe, is for basic authentication. When i do that, the Request Headers are MISSING the 'Authorize' header. Er... that's not right :( I have anonymous authentication only setup on the site. I don't want to have anon off and basic turned on .. because not all of the site requires basic.. only a few action methods. So .. why is this not working? Is this something to do with the fact my code is not sending a 401 challenge or some crap? For What It's Worth, my site is ASP.NET MVC1 running on IIS7 (and the same thing happens when i run it on cassini).

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• Is it possible to group validation?

  - by lambdabutz

  I am using a lot of my own validation methods to compare the data from one association to the other. I've noticed that I'm constantly checking that my associations aren't nil before trying to call anything on them, but I am also validating their presence, and so I feel that my nil checks are redundant. Here's an example: class House < ActiveRecord::Base has_one :enterance, :class => Door has_one :exit, :class => Door validates_presence_of :enterance, :exit validate :not_a_fire_hazard def not_a_fire_hazard if enterance && exit && enterance.location != exit.location errors.add_to_base('If there is a fire you will most likely die') return false end end end I feel like I am repeating myself by checking the existence of enterance and exit within my own validation. Is there a more "The Rails Way" to do this?

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• Scala loop returns as Unit and compiler points to "for" syntax?

  - by DeLongey

  Seems like Unit is the theme of my troubles today. I'm porting a JSON deserializer that uses Gson and when it comes to this for loop: def deserialize(json:JsonElement, typeOfT:Type, context:JsonDeserializationContext) = { var eventData = new EventData(null, null) var jsonObject = json.getAsJsonObject for(entry <- jsonObject.entrySet()) { var key = entry.getKey() var element = entry.getValue() element if("previous_attributes".equals(key)) { var previousAttributes = new scala.collection.mutable.HashMap[String, Object]() populateMapFromJSONObject(previousAttributes, element.getAsJsonObject()) eventData.setPreviousAttributes(previousAttributes) eventData } else if ("object".equals(key)) { val `type` = element.getAsJsonObject().get("object").getAsString() var cl = objectMap.get(`type`).asInstanceOf[StripeObject] var `object` = abstractObject.retrieve(cl, key) eventData.setObject(`object`) eventData } } } The compiler spits out the error type mismatch; found : Unit required: com.stripe.EventData and it points to this line here: for(entry <- jsonObject.entrySet()) Questions Confirm that it is indeed the Gson method entrySet() appearing as unit? If not, what part of the code is creating the issue? I've set return types/values for eventData class methods Is there a workaround for the Gson Unit issue? Thanks!

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• Scroll Gestures not Passed to IScrollInfo implementing panel in Windows Phone 7 CTP

  - by user50088

  I am using a custom panel as a ItemsPanel for a ItemsControl in a with a custom template that provides for a scroll viewer. (See Xaml below.) So long as my panel does not implement IScrollInfo, scrolling works in this scenerio. I implement IScrollInfo and update my viewport and extent sizes in measure override. The scroll bar shows the correct relative size, and if I call the IScrollInfo methods directly, scrolling works as expected. However, the drag and flick gestures no longer scroll the content. Putting a breakpoint on the input of every IScrollInfo method shows that drag and pick are not calling the interface. Removing the IScrollInfo interface declaration restores the scroll on drag and flick behavior. Is there a simple way to restore the flick and pan gestures to ItemControls with panels that implement IScrollInfo?

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• What free expert system can You recommend (with higher functionality then CLIPS)?

  - by Martin

  Hi, I'm trying to find best free expert system, with the highest functionality. I know about CLIPS, but is there another system, for example being able to accept percent of confidence for each rule (fuzzy logic). I need it to know will I be able to do fast a short project using expert system, with highest functionality. But anyways, it's interesting is there an open source program that aims to gather different AI methods (whitch there are plenty of), and use them together. So I would be extremely thankeful for any info about more robust CLIPS, or similar programs. Thanks!

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• changing a picker to table view OR having multiple table views on the same view

  - by Brodie4598

  Hello - My iPad app was rejected due to my use of a picker. The picker was used to control a table view. In my view, a picker was displaying a series of items and when one of those items was selected, it used that selection to populate a table with data. (hopefully that makes sense). Now I need to do this without the picker so I need to have the data that was in the picker be represented in a table view. My question, is how do I have multiple tableViews in the same view? I'm guessing I need to have some kind of if statement in the tableview delegate methods, but I'm not quite sure what the if statement needs to be. Or maybe i'm thinking of this the totally wrong way thanks

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• Proper structure for many test cases in Python with unittest

  - by mellort

  I am looking into the unittest package, and I'm not sure of the proper way to structure my test cases when writing a lot of them for the same method. Say I have a fact function which calculates the factorial of a number; would this testing file be OK? import unittest class functions_tester(unittest.TestCase): def test_fact_1(self): self.assertEqual(1, fact(1)) def test_fact_2(self): self.assertEqual(2, fact(2)) def test_fact_3(self): self.assertEqual(6, fact(3)) def test_fact_4(self): self.assertEqual(24, fact(4)) def test_fact_5(self): self.assertFalse(1==fact(5)) def test_fact_6(self): self.assertRaises(RuntimeError, fact, -1) #fact(-1) if __name__ == "__main__": unittest.main() It seems sloppy to have so many test methods for one method. I'd like to just have one testing method and put a ton of basic test cases (ie 4! ==24, 3!==6, 5!==120, and so on), but unittest doesn't let you do that. What is the best way to structure a testing file in this scenario? Thanks in advance for the help.

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• Running a stored procedure in a SqlDataSource on button click

  - by Gapton

  I am building a C# ASP.NET page where I want to call a stored procedure in a database. I have setup a SqlDataSource which points to the stored procedure. Parameters are obtained from the Web's control directly (TextBox) I have a button, when the user clicks it it should run the stored procedure, so I was going to add code like this : mySqlDataSource.run() or mySqlDataSource.exec() or mySqlDataSource.storedProcedure() but of course none of these methods exist. How do I initial the stored procedure? and how do I get the value returned by the stored procedure please? Thank you!

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• How can I add a field with an array value to my Perl object?

  - by superstar

  What's the difference between these two constructors in perl? 1) sub new { my $class = shift; my $self = {}; $self->{firstName} = undef; $self->{lastName} = undef; $self->{PEERS} = []; bless ($self, $class); return $self; } 2) sub new { my $class = shift; my $self = { _firstName => shift, _lastName => shift, _ssn => shift, }; bless $self, $class; return $self; } I am using the second one so far, but I need to implement the PEERS array in the second one? How do I do it with the second constructor and how can we use get and set methods on those array variables?

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• XMLEncoder and PersistenceDelegate

  - by Johannes Rössel

  I'm trying to use XMLEncoder to write an object graph (tree in my case) to a file. However, one class contained in it is not actually a Java bean and I don't particularly like making its guts publicly accessible. It's accessed more like a list and has appropriate add methods. I've already written a custom PersistenceDelegate to deal with that. However, is there any way for XMLEncoder to pick it up on its own or do I really need to add it whenever I use an encoder to write a graph that may contain said class?

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• Visual Studio - easy way to bring up type definition as source code

  - by Igor Zevaka

  Oftentimes I want to bring up a system class in a source view, so that I can browse the properties and methods exposed by the class in a source view. Below is the screenshot of what I mean: Usually I do this by selecting the class name and pressing F12 (or right clickGo To Definition). However, if I haven't got it anywhere ready, i have type it up and then do Go To Definition. Most of the time I have to delete what I typed later on. Is there a way to bring up this view without having to type the class name? The VS2010 Navigate To dialog doesn't support this.

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• How should I declare default values for instance variables in Python?

  - by int3

  Should I give my class members default values like this: class Foo: num = 1 or like this? class Foo: def __init__(self): self.num = 1 In this question I discovered that in both cases, bar = Foo() bar.num += 1 is a well-defined operation. I understand that the first method will give me a class variable while the second one will not. However, if I do not require a class variable, but only need to set a default value for my instance variables, are both methods equally good? Or one of them more 'pythonic' than the other? One thing I've noticed is that in the Django tutorial, they use the second method to declare Models. Personally I think the second method is more elegant, but I'd like to know what the 'standard' way is.

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• URL of the website calling Restlet API

  - by Christopher McCann

  I have a Restlet API and the methods exposed on it are called by a PHP web app. This web app is accessible by several domain names and depending on the domain certain aspects of the app are changed (look and feel, content etc). Is there a way for Restlet to determine the URL of the calling web app? I have used getReference() but all I can get is the (internal) IP address of the calling web server (not the domain name). My only other alternative is to pass the URL of the web app with every request to the API but it would be cleaner if Restlet already knew. Thanks

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• Java reflection for generics

  - by Vijay Bhore

  I am using Java Reflection to expose methods in custom eclipse tool. I am writing method getReturnType which accepts java.lang.reflect.Method as input and returns object of Class private static Class<?> getReturnType(Method method) { Type type = ((ParameterizedType)method.getGenericReturnType()).getRawType(); return getClass(type); } This code compiles well but at runtime i get the below exception while casting Type to ParameterizedType. java.lang.ClassCastException: java.lang.Class cannot be cast to java.lang.reflect.ParameterizedType Please suggest. Thanks!

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• Why make anything internal?

  - by c-charp N00b

  I don't really see the point of making methods or classes internal. In my very limited understanding, all it does is make working with your code very difficult for other programmers. Say I write Big_Important_Class for Project A and make said class internal. Then Bob, working on Project B needs to use my class to have project B work with Project A, but since its internal he can't. As of now this is the only thing I have seen internals do, make things really complicated for the guy working on Project B. I know there has to be a good reason to use internals, but I don't see any. Could someone please explain how they can be a good thing?

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• C# implementation of PushbackInputStream

  - by Mark Heath

  I need a C# implementation of Java's PushbackInputStream. I have made my own very basic one, but I wondered if there was a well tested and decently performing version already available somewhere. As it happens I always push back the same bytes I read so really it just needs to be able to reposition backwards, buffering up to a number of bytes I specify. (like Java's BufferedInputStream with the mark and reset methods). Update: I should add that I can't simply reposition the stream as CanSeek may be false. (e.g. when the input steam is a NetworkStream)

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