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  • How to test method call order with Moq

    - by Finglas
    At the moment I have: [Test] public void DrawDrawsAllScreensInTheReverseOrderOfTheStack() { // Arrange. var screenMockOne = new Mock<IScreen>(); var screenMockTwo = new Mock<IScreen>(); var screens = new List<IScreen>(); screens.Add(screenMockOne.Object); screens.Add(screenMockTwo.Object); var stackOfScreensMock = new Mock<IScreenStack>(); stackOfScreensMock.Setup(s => s.ToArray()).Returns(screens.ToArray()); var screenManager = new ScreenManager(stackOfScreensMock.Object); // Act. screenManager.Draw(new Mock<GameTime>().Object); // Assert. screenMockOne.Verify(smo => smo.Draw(It.IsAny<GameTime>()), Times.Once(), "Draw was not called on screen mock one"); screenMockTwo.Verify(smo => smo.Draw(It.IsAny<GameTime>()), Times.Once(), "Draw was not called on screen mock two"); } But the order in which I draw my objects in the production code does not matter. I could do one first, or two it doesn't matter. However it should matter as the draw order is important. How do you (using Moq) ensure methods are called in a certain order? Edit I got rid of that test. The draw method has been removed from my unit tests. I'll just have to manually test it works. The reversing of the order though was taken into a seperate test class where it was tested so it's not all bad. Thanks for the link about the feature they are looking into. I sure hope it gets added soon, very handy.

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  • Choosing between instance methods and separate functions?

    - by StackedCrooked
    Adding functionality to a class can be done by adding a method or by defining a function that takes an object as its first parameter. Most programmers that I know would choose for the solution of adding a instance method. However, I sometimes prefer to create a separate function. For example, in the example code below Area and Diagonal are defined as separate functions instead of methods. I find it better this way because I think these functions provide enhancements rather than core functionality. Is this considered a good/bad practice? If the answer is "it depends", then what are the rules for deciding between adding method or defining a separate function? class Rect { public: Rect(int x, int y, int w, int h) : mX(x), mY(y), mWidth(w), mHeight(h) { } int x() const { return mX; } int y() const { return mY; } int width() const { return mWidth; } int height() const { return mHeight; } private: int mX, mY, mWidth, mHeight; }; int Area(const Rect & inRect) { return inRect.width() * inRect.height(); } float Diagonal(const Rect & inRect) { return std::sqrt(std::pow(static_cast<float>(inRect.width()), 2) + std::pow(static_cast<float>(inRect.height()), 2)); }

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  • WCF REST adding data using POST or PUT 400 Bad Request

    - by user55474
    HI How do i add data using wcf rest architecture. I dont want to use the channelfactory to call my method. Something similar to the webrequest and webresponse used for GET. Something similar to the ajax WebServiceProxy restInvoke Or do i always have to use the Webchannelfactory implementation I am getting a 400 BAD request by using the following Dim url As String = "http://localhost:4475/Service.svc/Entity/Add" Dim req As WebRequest = WebRequest.Create(url) req.Method = "POST" req.ContentType = "application/xml; charset=utf-8" req.Timeout = 30000 req.Headers.Add("SOAPAction", url) Dim xEle As XElement xEle = <Entity xmlns:i="http://www.w3.org/2001/XMLSchema-instance"> <Name>Entity1</Name> </Entity> Dim sXML As String = xEle .Value req.ContentLength = sXML.Length Dim sw As New System.IO.StreamWriter(req.GetRequestStream()) sw.Write(sXML) sw.Close() Dim res as HttpWebResponse = req.GetResponse() Sercice Contract is as follows <OperationContract()> _ <WebInvoke(Method:="PUT", UriTemplate:="Entity/Add")> _ Function AddEntity(ByVal e1 As Entity) DataContract is as follows <Serializable()> _ <DataContract()> _ Public Class Entity private m_Name as String <DataMember()> _ Public Property Name() As String Get Return m_Name End Get Set(ByVal value As String) m_Name = value End Set End Property End Class thanks

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  • Amazone API ItemSearch returns (400) Bad Request.

    - by BuzzBubba
    I'm using a simple example from Amazon documentation for ItemSearch and I get a strange error: "The remote server returned an unexpected response: (400) Bad Request." This is the code: public static void Main() { //Remember to create an instance of the amazon service, including you Access ID. AWSECommerceServicePortTypeClient service = new AWSECommerceServicePortTypeClient(new BasicHttpBinding(), new EndpointAddress( "http://webservices.amazon.com/onca/soap?Service=AWSECommerceService")); AWSECommerceServicePortTypeClient client = new AWSECommerceServicePortTypeClient( new BasicHttpBinding(), new EndpointAddress("http://webservices.amazon.com/onca/soap?Service=AWSECommerceService")); // prepare an ItemSearch request ItemSearchRequest request = new ItemSearchRequest(); request.SearchIndex = "Books"; request.Title = "Harry+Potter"; request.ResponseGroup = new string[] { "Small" }; ItemSearch itemSearch = new ItemSearch(); itemSearch.Request = new ItemSearchRequest[] { request }; itemSearch.AWSAccessKeyId = accessKeyId; // issue the ItemSearch request try { ItemSearchResponse response = client.ItemSearch(itemSearch); // write out the results foreach (var item in response.Items[0].Item) { Console.WriteLine(item.ItemAttributes.Title); } } catch(Exception e) { Console.ForegroundColor = ConsoleColor.Red; Console.WriteLine(e.Message); Console.ForegroundColor = ConsoleColor.White; Console.WriteLine("Press any key to quit..."); Clipboard.SetText(e.Message); } Console.ReadKey(); What is wrong?

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  • File descriptor limits and default stack sizes

    - by Charles
    Where I work we build and distribute a library and a couple complex programs built on that library. All code is written in C and is available on most 'standard' systems like Windows, Linux, Aix, Solaris, Darwin. I started in the QA department and while running tests recently I have been reminded several times that I need to remember to set the file descriptor limits and default stack sizes higher or bad things will happen. This is particularly the case with Solaris and now Darwin. Now this is very strange to me because I am a believer in 0 required environment fiddling to make a product work. So I am wondering if there are times where this sort of requirement is a necessary evil, or if we are doing something wrong. Edit: Great comments that describe the problem and a little background. However I do not believe I worded the question well enough. Currently, we require customers, and hence, us the testers, to set these limits before running our code. We do not do this programatically. And this is not a situation where they MIGHT run out, under normal load our programs WILL run out and seg fault. So rewording the question, is requiring the customer to change these ulimit values to run our software to be expected on some platforms, ie, Solaris, Aix, or are we as a company making it to difficult for these users to get going? Bounty: I added a bounty to hopefully get a little more information on what other companies are doing to manage these limits. Can you set these pragmatically? Should we? Should our programs even be hitting these limits or could this be a sign that things might be a bit messy under the covers? That is really what I want to know, as a perfectionist a seemingly dirty program really bugs me.

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  • VSC++, virtual method at bad adress, curious bug

    - by antoon.groenewoud
    Hello, This guy: virtual phTreeClass* GetTreeClass() const { return (phTreeClass*)m_entity_class; } When called, crashed the program with an access violation, even after a full recompile. All member functions and virtual member functions had correct memory adresses (I hovered mouse over the methods in debug mode), but this function had a bad memory adress: 0xfffffffc. Everything looked okay: the 'this' pointer, and everything works fine up until this function call. This function is also pretty old and I didn't change it for a long time. The problem just suddenly popped up after some work, which I commented all out to see what was doing it, without any success. So I removed the virtual, compiled, and it works fine. I add virtual, compiled, and it still works fine! I basically changed nothing, and remember that I did do a full recompile earlier, and still had the error back then. I wasn't able to reproduce the problem. But now it is back. I didn't change anything. Removing virtual fixes the problem. Sincerely, Antoon

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  • Reading a binary file in perl: Bad File Descriptor

    - by Magicked
    I'm trying to read a binary file 40 bytes at a time, then check to see if all those bytes are 0x00, and if so ignore them. If not, it will write them back out to another file (basically just cutting out large blocks of null bytes). This may not be the most efficient way to do this, but I'm not worried about that. However, right now I'm getting a "Bad File Descriptor" error and I cannot figure out why. my $comp = "\x00" * 40; my $byte_count = 0; my $infile = "/home/magicked/image1"; my $outfile = "/home/magicked/image1_short"; open IN, "<$infile"; open OUT, ">$outfile"; binmode IN; binmode OUT; my ($buf, $data, $n); while (read (IN, $buf, 40)) { ### Problem is here ### $boo = 1; for ($i = 0; $i < 40; $i++) { if ($comp[$i] != $buf[$i]) { $i = 40; print OUT $buf; $byte_count += 40; } } } die "Problems! $!\n" if $!; close OUT; close IN; I marked with a comment where it is breaking. Thanks for any help!

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  • Delphi: How to avoid EIntOverflow underflow when subtracting?

    - by Ian Boyd
    Microsoft already says, in the documentation for GetTickCount, that you could never compare tick counts to check if an interval has passed. e.g.: Incorrect (pseudo-code): DWORD endTime = GetTickCount + 10000; //10 s from now ... if (GetTickCount > endTime) break; The above code is bad because it is suceptable to rollover of the tick counter. For example, assume that the clock is near the end of it's range: endTime = 0xfffffe00 + 10000 = 0x00002510; //9,488 decimal Then you perform your check: if (GetTickCount > endTime) Which is satisfied immediatly, since GetTickCount is larger than endTime: if (0xfffffe01 > 0x00002510) The solution Instead you should always subtract the two time intervals: DWORD startTime = GetTickCount; ... if (GetTickCount - startTime) > 10000 //if it's been 10 seconds break; Looking at the same math: if (GetTickCount - startTime) > 10000 if (0xfffffe01 - 0xfffffe00) > 10000 if (1 > 10000) Which is all well and good in C/C++, where the compiler behaves a certain way. But what about Delphi? But when i perform the same math in Delphi, with overflow checking on ({Q+}, {$OVERFLOWCHECKS ON}), the subtraction of the two tick counts generates an EIntOverflow exception when the TickCount rolls over: if (0x00000100 - 0xffffff00) > 10000 0x00000100 - 0xffffff00 = 0x00000200 What is the intended solution for this problem? Edit: i've tried to temporarily turn off OVERFLOWCHECKS: {$OVERFLOWCHECKS OFF}] delta = GetTickCount - startTime; {$OVERFLOWCHECKS ON} But the subtraction still throws an EIntOverflow exception. Is there a better solution, involving casts and larger intermediate variable types?

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  • IOS : BAD ACCESS when trying to add a new Entity object

    - by Maverick447
    So i'm using coredata to model my relationships . This is the model in brief Type A can have one or more types of type B Type B has a inverse relationship of being associated with one of type A Type B can have one or more types of type C Type C has a inverse relationship of being associated with one of type B From a UI standpoint , I have a Navigation controller with controllers that successively sets up the first A object (VC-1) , then another viewcontroller (VC-2) creates a B object ( I pass in the A object to this controller) and the B object is added to the A object . Similarly the same thing happens with B and C . The third Viewcontroller (VC3) first creates a C object and assigns it to the passed B Object . Also between these viewcontrollers the managedObjectCOntext is also passed . SO my use case is such that while viewcontroller (VC-3) is the top controller a button action will keep creating multiple objects of type C and add them to the same type B object that was passed . Also as part of this function I save the managedObject context after saving each type C . e.g. code in viewcontroller 3 - (void) SaveNewTypeC { TypeC *newtypeC = (Question*)[NSEntityDescription insertNewObjectForEntityForName:@"TypeC" inManagedObjectContext:managedObjectContext]; [newtypeC setProp1:] ; [newtypeC setProp2:] .. .. **[typeBObject addTypeCInTypeBObject:newtypeC];** [section setTotalCObjectCount:[ NSNumber numberWithInt:typeCIndex++]]; NSError *error = nil; if (![managedObjectContext save:&error]) { // Handle error NSLog(@"Unresolved error %@, %@, %@", error, [error userInfo],[error localizedDescription]); exit(-1); // Fail } [newtypeC release]; } - (IBAction)selectedNewButton:(id)sender { [self SaveNewTypeC]; [self startRepeatingTimer]; } The BAD ACCESS seems to appear when the bold line above executes Relating to some HashValue . Any clues on resolving this would be helpful .

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  • Displaying performance metrics in a modern web app?

    - by Charles
    We're updating our ancient internal PHP application at work. Right now, we gather extensive performance measurements on every pageview, and log them to the database. Additionally, users requested that some of the metrics be displayed at the bottom of the page. This worked out pretty well for us, because the last thing that the application does on every request is include the file containing the HTML footer. The updated parts of the application use an MVC framework and a Dispatch/Request/Response loop. The page footer is no longer the last thing done. In fact, it could very well be the first thing done, before the rest of the page is created. Because we can grab the Response before it's returned to the user, we could try to include placeholders for the performance metrics in the footer and simply replace them with the actual numbers, but this strikes me as a bad idea somehow. How do you handle this in your modern web app? While we're using PHP, I'm curious how it's done in a Ruby/Rails app, and in your favorite Python framework.

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  • Where should my "filtering" logic reside with Linq-2-SQL and ASP.NET-MVC in View or Controller?

    - by Nate Bross
    I have a main Table, with several "child" tables. TableA and TableAChild1 and TableAChild2. I have a view which shows the information in TableA, and then has two columns of all items in TableAChild1 and TableAChild2 respectivly, they are rendered with Partial views. Both child tables have a bit field for VisibleToAll, and depending on user role, I'd like to either display all related rows, or related rows where VisibleToAll = true. This code, feels like it should be in the controller, but I'm not sure how it would look, because as it stands, the controller (limmited version) looks like this: return View("TableADetailView", repos.GetTableA(id)); Would something like this be even work, and would it be bad what if my DataContext gets submitted, would that delete all the rows that have VisibleToAll == false? var tblA = repos.GetTableA(id); tblA.TableAChild1 = tblA.TableAChild1.Where(tmp => tmp.VisibleToAll == true); tblA.TableAChild2 = tblA.TableAChild2.Where(tmp => tmp.VisibleToAll == true); return View("TableADetailView", tblA); It would also be simple to add that logic to the RendarPartial call from the main view: <% Html.RenderPartial("TableAChild1", Model.TableAChild1.Where(tmp => tmp.VisibleToAll == true); %>

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  • Is it bad practise to initialise fields outside of an explicit constructor

    - by MrTortoise
    So its monday and we are arguing about coding practises. The examples here are a litttle too simple, but the real deal has several constructors. In order to initialise the simple values (eg dates to their min value) I have moved the code out of the constructors and into the field definitions. public class ConstructorExample { string _string = "John"; } public class ConstructorExample2 { string _string; public ConstructorExample2() { _string = "John"; } } How should it be done by the book. I tend to be very case by case and so am maybe a little lax abotu this kind of thing. However i feel that accams razor tells me to move the initialisation out of multiple constructors. Of course I could always move this shared initialisation into a private method. The question is essentially ... is initialising fields where they are defined as opposed to the constructor bad in any way? The argument I am facing is one of error handling, but i do not feel it is relevant as there are no possible exceptions that won't be picked up at compile time.

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  • Why do people keep parsing HTML using regex? [closed]

    - by polygenelubricants
    As much as I love regular expressions, it's obvious to me that it's not the best tool for parsing HTML, especially given the numerous good HTML parsers out there. And yet there are numerous questions on stackoverflow that attempts to parse HTML using regex. And people would always point out what a bad idea that is in the comments. And the accepted answer would often have a disclaimer how this isn't really the ideal way of doing things. But based on the constant flow of questions, it still seems that people keep parsing HTML using regex, despite the perceived difficulty in reading and maintaining it (and that's putting correctness aside for now). So my question is: why? Is it because it's easy to learn? Is it because it's faster? Is it because it's the industry standard? Is it because there are already so many reusable regexes to build from? Is it because 100% correctness is never really the objective? (90% good enough?) etc... I'd also like to hear from the downvoters why they did so. Is it because: There's absolutely nothing wrong with using regex to parse HTML and asking "Why?" is just dumb? The premise of the question is flawed because the people who are using regex to parse HTML is such a small minority?

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  • Large Switch statements: Bad OOP?

    - by Mystere Man
    I've always been of the opinion that large switch statements are a symptom of bad OOP design. In the past, I've read articles that discuss this topic and they have provided altnerative OOP based approaches, typically based on polymorphism to instantiate the right object to handle the case. I'm now in a situation that has a monsterous switch statement based on a stream of data from a TCP socket in which the protocol consists of basically newline terminated command, followed by lines of data, followed by an end marker. The command can be one of 100 different commands, so I'd like to find a way to reduce this monster switch statement to something more manageable. I've done some googling to find the solutions I recall, but sadly, Google has become a wasteland of irrelevant results for many kinds of queries these days. Are there any patterns for this sort of problem? Any suggestions on possible implementations? One thought I had was to use a dictionary lookup, matching the command text to the object type to instantiate. This has the nice advantage of merely creating a new object and inserting a new command/type in the table for any new commands. However, this also has the problem of type explosion. I now need 100 new classes, plus I have to find a way to interface them cleanly to the data model. Is the "one true switch statement" really the way to go? I'd appreciate your thoughts, opinions, or comments.

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  • How to use interfaces in exception handling

    - by vikp
    Hi, I'm working on the exception handling layer for my application. I have read few articles on interfaces and generics. I have used inheritance before quite a lot and I'm comfortable with in that area. I have a very brief design that I'm going to implement: public interface IMyExceptionLogger { public void LogException(); // Helper methods for writing into files,db, xml } I'm slightly confused what I should be doing next. public class FooClass: IMyExceptionLogger { // Fields // Constructors } Should I implement LogException() method within FooClass? If yes, than I'm struggling to see how I'm better of using an interface instead of the concrete class... I have a variety of classes that will make a use of that interface, but I don't want to write an implementation of that interface within each class. In the same time If I implement an interface in one class, and then use that class in different layers of the application I will be still using concrete classes instead of interfaces, which is a bad OO design... I hope this makes sense. Any feedback and suggestions are welcome. Please notice that I'm not interested in using net4log or its competitors because I'm doing this to learn. Thank you Edit: Wrote some more code. So I will implement variety of loggers with this interface, i.e. DBExceptionLogger, CSVExceptionLogger, XMLExceptionLogger etc. Than I will still end up with concrete classes that I will have to use in different layers of my application.

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  • Which options do I have for Java process communication?

    - by Dmitriy Matveev
    We have a place in a code of such form: void processParam(Object param) { wrapperForComplexNativeObject result = jniCallWhichMayCrash(param); processResult(result); } processParam - method which is called with many different arguments. jniCallWhichMayCrash - a native method which is intended to do some complex processing of it's parameter and to create some complex object. It can crash in some cases. wrapperForComplexNativeObject - wrapper type generated by SWIG processResult - a method written in pure Java which processes it's parameter by creation of several kinds (by the kinds I'm not meaning classes, maybe some like hierarchies) of objects: 1 - Some non-unique objects which are referencing each other (from the same hierarchy), these objects can have duplicates created from the invocations of processParam() method with different parameter values. Since it's costly to keep all the duplicates it's necessary to cache them. 2 - Some unique objects which are referencing each other (from the same hierarchy) and some of the objects of 1st kind. After processParam is executed for each of the arguments from some set the data created in processResult will be processed together. The problem is in fact that jniCallWhichMayCrash method may crash the entire JVM and this will be very bad. The reason of crash may be such that it can happen for one argument value and not for the other. We've decided that it's better to ignore crashes inside of JVM and just skip some chunks of data when such crashes occur. In order to do this we should run processParam function inside of separate process and pass the result somehow (HOW? HOW?! This is a question) to the main process and in case of any crashes we will only lose some part of data (It's ok) without lose of everything else. So for now the main problem is implementation of transport between different processes. Which options do I have? I can think about serialization and transmitting of binary data by the streams, but serialization may be not very fast due to object complexity. Maybe I have some other options of implementing this?

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  • Is it advisable to have an interface as the return type?

    - by wb
    I have a set of classes with the same functions but with different logic. However, each class function can return a number of objects. It is safe to set the return type as the interface? Each class (all using the same interface) is doing this with different business logic. protected IMessage validateReturnType; <-- This is in an abstract class public bool IsValid() <-- This is in an abstract class { return (validateReturnType.GetType() == typeof(Success)); } public IMessage Validate() { if (name.Length < 5) { validateReturnType = new Error("Name must be 5 characters or greater."); } else { validateReturnType = new Success("Name is valid."); } return validateReturnType; } Are there any pitfalls with unit testing the return type of an function? Also, is it considered bad design to have functions needing to be run in order for them to succeed? In this example, Validate() would have to be run before IsValid() or else IsValid() would always return false. Thank you.

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  • White-box testing in Javascript - how to deal with privacy?

    - by Max Shawabkeh
    I'm writing unit tests for a module in a small Javascript application. In order to keep the interface clean, some of the implementation details are closed over by an anonymous function (the usual JS pattern for privacy). However, while testing I need to access/mock/verify the private parts. Most of the tests I've written previously have been in Python, where there are no real private variables (members, identifiers, whatever you want to call them). One simply suggests privacy via a leading underscore for the users, and freely ignores it while testing the code. In statically typed OO languages I suppose one could make private members accessible to tests by converting them to be protected and subclassing the object to be tested. In Javascript, the latter doesn't apply, while the former seems like bad practice. I could always wall back to black box testing and simply check the final results. It's the simplest and cleanest approach, but unfortunately not really detailed enough for my needs. So, is there a standard way of keeping variables private while still retaining some backdoors for testing in Javascript?

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  • Is it better for class data to be passed internally or accessed directly?

    - by AaronSzy
    Example: // access fields directly private void doThis() { return doSomeWork(this.data); } // receive data as an argument private void doThis(data) { return doSomeWork(data); } The first option is coupled to the value in this.data while the second option avoids this coupling. I feel like the second option is always better. It promotes loose coupling WITHIN the class. Accessing global class data willy-nilly throughout just seems like a bad idea. Obviously this class data needs to be accessed directly at some point. However, if accesses, to this global class data can be eliminated by parameter passing, it seems that this is always preferable. The second example has the advantage of working with any data of the proper type, whereas the first is bound to working with the just class data. Even if you don't NEED the additional flexibility, it seems nice to leave it as an option. I just don't see any advantage in accessing member data directly from private methods as in the first example. Whats the best practice here? I've referenced code complete, but was not able to find anything on this particular issue.

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  • Is there a case for parameterising using Abstract classes rather than Interfaces?

    - by Chris
    I'm currently developing a component based API that is heavily stateful. The top level components implement around a dozen interfaces each. The stock top-level components therefore sit ontop of a stack of Abstract implementations which in turn contain multiple mixin implementations and implement multiple mixin interfaces. So far, so good (I hope). The problem is that the base functionality is extremely complex to implement (1,000s of lines in 5 layers of base classes) and therefore I do not wish for component writers to implement the interfaces themselves but rather to extend my base classes (where all the boiler plate code is already written). If the API therefore accepts interfaces rather than references to the Abstract implementation that I wish for component writers to extends, then I have a risk that the implementer will not perform the validation that is both required and assumed by other areas of code. Therefore, my question is, is it sometimes valid to paramerise API methods using an abstract implementation reference rather than a reference to the interface(s) that it implements? Do you have an example of a well-designed API that uses this technique or am I trying to talk myself into bad-practice?

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  • Global State and Singletons Dependency injection

    - by Manu
    this is a problem i face lot of times when i am designing a new app i'll use a sample problem to explain this think i am writing simple game.so i want to hold a list of players. i have few options.. 1.use a static field in some class private static ArrayList<Player> players = new ArrayList<Integer>(); public Player getPlayer(int i){ return players.get(i); } but this a global state 2.or i can use a singleton class PlayerList{ private PlayerList instance; private PlayerList(){...} public PlayerList getInstance() { if(instance==null){ ... } return instance; } } but this is bad because it's a singleton 3.Dependency injection class Game { private PlayerList playerList; public Game(PlayerList list) { this.list = list; } public PlayerList getPlayerList() { return playerList; } } this seems good but it's not, if any object outside Game need to look at PlayerList (which is the usual case) i have to use one of the above methods to make the Game class available globally. so I just add another layer to the problem. didn't actually solve anything. what is the optimum solution ? (currently i use Singleton approach)

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  • Is it okay to violate the principle that collection properties should be readonly for performance?

    - by uriDium
    I used FxCop to analyze some code I had written. I had exposed a collection via a setter. I understand why this is not good. Changing the backing store when I don't expect it is a very bad idea. Here is my problem though. I retrieve a list of business objects from a Data Access Object. I then need to add that collection to another business class and I was doing it with the setter method. The reason I did this was that it is going to be faster to make an assignment than to insert hundreds of thousands of objects one at a time to the collection again via another addElement method. Is it okay to have a getter for a collection in some scenarios? I though of rather having a constructor which takes a collection? I thought maybe I could pass the object in to the Dao and let the Dao populate it directly? Are there any other better ideas?

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  • When should I use Perl's AUTOLOAD?

    - by Robert S. Barnes
    In "Perl Best Practices" the very first line in the section on AUTOLOAD is: Don't use AUTOLOAD However all the cases he describes are dealing with OO or Modules. I have a stand alone script in which some command line switches control which versions of particular functions get defined. Now I know I could just take the conditionals and the evals and stick them naked at the top of my file before everything else, but I find it convenient and cleaner to put them in AUTOLOAD at the end of the file. Is this bad practice / style? If you think so why, and is there a another way to do it? As per brian's request I'm basically using this to do conditional compilation based on command line switches. I don't mind some constructive criticism. sub AUTOLOAD { our $AUTOLOAD; (my $method = $AUTOLOAD) =~ s/.*:://s; # remove package name if ($method eq 'tcpdump' && $tcpdump) { eval q( sub tcpdump { my $msg = shift; warn gf_time()." Thread ".threads->tid().": $msg\n"; } ); } elsif ($method eq 'loginfo' && $debug) { eval q( sub loginfo { my $msg = shift; $msg =~ s/$CRLF/\n/g; print gf_time()." Thread ".threads->tid().": $msg\n"; } ); } elsif ($method eq 'build_get') { if ($pipelining) { eval q( sub build_get { my $url = shift; my $base = shift; $url = "http://".$url unless $url =~ /^http/; return "GET $url HTTP/1.1${CRLF}Host: $base$CRLF$CRLF"; } ); } else { eval q( sub build_get { my $url = shift; my $base = shift; $url = "http://".$url unless $url =~ /^http/; return "GET $url HTTP/1.1${CRLF}Host: $base${CRLF}Connection: close$CRLF$CRLF"; } ); } } elsif ($method eq 'grow') { eval q{ require Convert::Scalar qw(grow); }; if ($@) { eval q( sub grow {} ); } goto &$method; } else { eval "sub $method {}"; return; } die $@ if $@; goto &$method; }

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  • hibernate column uniqueness question

    - by Seth
    I'm still in the process of learning hibernate/hql and I have a question that's half best practices question/half sanity check. Let's say I have a class A: @Entity public class A { @Id @GeneratedValue(strategy=GenerationType.AUTO) private Long id; @Column(unique=true) private String name = ""; //getters, setters, etc. omitted for brevity } I want to enforce that every instance of A that gets saved has a unique name (hence the @Column annotation), but I also want to be able to handle the case where there's already an A instance saved that has that name. I see two ways of doing this: 1) I can catch the org.hibernate.exception.ConstraintViolationException that could be thrown during the session.saveOrUpdate() call and try to handle it. 2) I can query for existing instances of A that already have that name in the DAO before calling session.saveOrUpdate(). Right now I'm leaning towards approach 2, because in approach 1 I don't know how to programmatically figure out which constraint was violated (there are a couple of other unique members in A). Right now my DAO.save() code looks roughly like this: public void save(A a) throws DataAccessException, NonUniqueNameException { Session session = sessionFactory.getCurrentSession(); try { session.beginTransaction(); Query query = null; //if id isn't null, make sure we don't count this object as a duplicate if(obj.getId() == null) { query = session.createQuery("select count(a) from A a where a.name = :name").setParameter("name", obj.getName()); } else { query = session.createQuery("select count(a) from A a where a.name = :name " + "and a.id != :id").setParameter("name", obj.getName()).setParameter("name", obj.getName()); } Long numNameDuplicates = (Long)query.uniqueResult(); if(numNameDuplicates > 0) throw new NonUniqueNameException(); session.saveOrUpdate(a); session.getTransaction().commit(); } catch(RuntimeException e) { session.getTransaction().rollback(); throw new DataAccessException(e); //my own class } } Am I going about this in the right way? Can hibernate tell me programmatically (i.e. not as an error string) which value is violating the uniqueness constraint? By separating the query from the commit, am I inviting thread-safety errors, or am I safe? How is this usually done? Thanks!

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

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

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