Search Results

Search found 20586 results on 824 pages for 'virtual methods'.

Page 192/824 | < Previous Page | 188 189 190 191 192 193 194 195 196 197 198 199  | Next Page >

  • Merits of .NET ORM data access methods Enity Framework vs. NHibernate vs. Subsonic vs. ADO.NET Datas

    - by Lloyd
    I have recently heard "fanboys" of different .NET ORM methodologies express strong, if not outlandish oppinions of other ORM methodologies. And frankly feel a bit in the dark. Could you please explain the key merits of each of these .NET ORM solutions? Entity Framework NHibernate Subsonic ADO.NET Datasets I have a good understanding of 1&4, and a cursory understanding of 2&3, but apparently not enough to understand the implied cultural perceptions of one towards the other.

    Read the article

  • help needed on deciphering the g++ vtable dumps

    - by Ganesh Kundapur
    Hi, for the fallow class hierarchy class W { public: virtual void f() { cout << "W::f()" << endl; } virtual void g() { cout << "W::g()" << endl; } }; class AW : public virtual W { public: void g() { cout << "AW::g()" << endl; } }; class BW : public virtual W { public: void f() { cout << "BW::f()" << endl; } }; class CW : public AW, public BW { }; g++ -fdump-class-hierarchy is Vtable for W W::_ZTV1W: 4u entries 0 (int ()(...))0 4 (int ()(...))(& _ZTI1W) 8 W::f 12 W::g Class W size=4 align=4 base size=4 base align=4 W (0xb6e3da50) 0 nearly-empty vptr=((& W::_ZTV1W) + 8u) Vtable for AW AW::_ZTV2AW: 7u entries 0 0u 4 0u 8 0u 12 (int ()(...))0 16 (int ()(...))(& _ZTI2AW) 20 W::f 24 AW::g VTT for AW AW::_ZTT2AW: 2u entries 0 ((& AW::_ZTV2AW) + 20u) 4 ((& AW::_ZTV2AW) + 20u) Class AW size=4 align=4 base size=4 base align=4 AW (0xb6dbf6c0) 0 nearly-empty vptridx=0u vptr=((& AW::_ZTV2AW) + 20u) W (0xb6e3da8c) 0 nearly-empty virtual primary-for AW (0xb6dbf6c0) vptridx=4u vbaseoffset=-0x00000000000000014 Vtable for BW BW::_ZTV2BW: 7u entries 0 0u 4 0u 8 0u 12 (int ()(...))0 16 (int ()(...))(& _ZTI2BW) 20 BW::f 24 W::g VTT for BW BW::_ZTT2BW: 2u entries 0 ((& BW::_ZTV2BW) + 20u) 4 ((& BW::_ZTV2BW) + 20u) Class BW size=4 align=4 base size=4 base align=4 BW (0xb6dbf7c0) 0 nearly-empty vptridx=0u vptr=((& BW::_ZTV2BW) + 20u) W (0xb6e3dac8) 0 nearly-empty virtual primary-for BW (0xb6dbf7c0) vptridx=4u vbaseoffset=-0x00000000000000014 Vtable for CW CW::_ZTV2CW: 14u entries 0 0u 4 0u 8 4u 12 (int ()(...))0 16 (int ()(...))(& _ZTI2CW) 20 BW::_ZTv0_n12_N2BW1fEv 24 AW::g 28 4294967292u 32 4294967292u 36 0u 40 (int ()(...))-0x00000000000000004 44 (int ()(...))(& _ZTI2CW) 48 BW::f 52 0u Construction vtable for AW (0xb6dbf8c0 instance) in CW CW::_ZTC2CW0_2AW: 7u entries 0 0u 4 0u 8 0u 12 (int ()(...))0 16 (int ()(...))(& _ZTI2AW) 20 W::f 24 AW::g Construction vtable for BW (0xb6dbf900 instance) in CW CW::_ZTC2CW4_2BW: 13u entries 0 4294967292u 4 4294967292u 8 0u 12 (int ()(...))0 16 (int ()(...))(& _ZTI2BW) 20 BW::f 24 0u 28 0u 32 4u 36 (int ()(...))4 40 (int ()(...))(& _ZTI2BW) 44 BW::_ZTv0_n12_N2BW1fEv 48 W::g VTT for CW CW::_ZTT2CW: 7u entries 0 ((& CW::_ZTV2CW) + 20u) 4 ((& CW::_ZTC2CW0_2AW) + 20u) 8 ((& CW::_ZTC2CW0_2AW) + 20u) 12 ((& CW::_ZTC2CW4_2BW) + 20u) 16 ((& CW::_ZTC2CW4_2BW) + 44u) 20 ((& CW::_ZTV2CW) + 20u) 24 ((& CW::_ZTV2CW) + 48u) Class CW size=8 align=4 base size=8 base align=4 CW (0xb6bea2d0) 0 vptridx=0u vptr=((& CW::_ZTV2CW) + 20u) AW (0xb6dbf8c0) 0 nearly-empty primary-for CW (0xb6bea2d0) subvttidx=4u W (0xb6e3db04) 0 nearly-empty virtual primary-for AW (0xb6dbf8c0) vptridx=20u vbaseoffset=-0x00000000000000014 BW (0xb6dbf900) 4 nearly-empty lost-primary subvttidx=12u vptridx=24u vptr=((& CW::_ZTV2CW) + 48u) W (0xb6e3db04) alternative-path what are each entries in Vtable for AW AW::_ZTV2AW: 7u entries 0 0u // ? 4 0u // ? 8 0u // ? Vtable for CW CW::_ZTV2CW: 14u entries 0 0u // ? 4 0u // ? 8 4u // ? 12 (int ()(...))0 16 (int ()(...))(& _ZTI2CW) 20 BW::_ZTv0_n12_N2BW1fEv // ? 24 AW::g 28 4294967292u // ? 32 4294967292u // ? 36 0u // ? 40 (int ()(...))-0x00000000000000004 // some delta 44 (int ()(...))(& _ZTI2CW) 48 BW::f 52 0u // ? Thanks, Ganesh

    Read the article

  • JavaScript multithreading

    - by Krzysztof Hasinski
    I'm working on comparison for several different methods of implementing (real or fake) multithreading in JavaScript. As far as I know only webworkers and Google Gears WorkerPool can give you real threads (ie. spread across multiple processors with real parallel execution). I've found the following methods: switch between tasks using yield() use setInterval() (or other non-blocking function) with threads waiting one for another use Google Gears WorkerPool threads (with plugin) use html5 web workers I read related questions and found several variations of the above methods, but most of those questions are old, so there might be a few new ideas. I'm wondering - how else can you achieve multithreading in JavaScript? Any other important methods? UPDATE: As pointed out in comments what I really meant was concurrency. UPDATE 2: I found information that Silverlight + JScript supports multithreading, but I'm unable to verify this. UPDATE 3: Google deprecated Gears: http://code.google.com/apis/gears/api_workerpool.html

    Read the article

  • Apache 2: I have multiple domain names I want to point to one Virtual Host. Do I use ServerAlias?

    - by Chris Altman
    I have multiple domain names, for example: www.foo.com www.goo.com www.moo.com www.coo.com I want all of these domain names to resolve to one website AND to redirect to www.foo.com What is the best method to achieve this? Multiple entries? Use ServerAlias? Something else? If the best method is ServerAlias, what is the syntax? ServerAlias www.goo.com, www.moo.com, www.coo.com

    Read the article

  • Is it good practice to call module functions directly in VB.NET?

    - by froadie
    I have a Util module in my VB.NET program that has project-wide methods such as logging and property parsing. The general practice where I work seems to be to call these methods directly without prefixing them with Util. When I was new to VB, it took me a while to figure out where these methods/functions were coming from. As I use my own Util methods now, I can't help thinking that it's a lot clearer and more understandable to add Util. before each method call (you know immediately that it's user-defined but not within the current class, and where to find it), and is hardly even longer. What's the general practice when calling procedures/functions of VB modules? Should we prefix them with the module name or not?

    Read the article

  • How do I add application specific code to Rails' plugin?

    - by Waseem
    Hi, I am using facebooker in one of my applications. I want to add some application specific methods to various methods in it? e.g. In facebooker/lib/facebooker/models/user.rb module Facebooker class User # I want to add my methods here. for e.g my_method end end I can not directly put my_method in the plugin itself since I also want to access my models from there. Not defining the methods in plugin code itself will also be helpful when I upgrade.

    Read the article

  • How can I display an ASP.NET MVC html part from one application in another

    - by Frank Sessions
    We have several asp.net MVC apps in the following setup SecurityApp (root application - handles forms auth for SSO and has a profile edit page) Application1 (virtual directory) Application2 (virtual directory) Application3 (virtual directory) so that domain.com points to SecurityApp and domain.com/Application1 etc point to their associated virtual directories. All of our Single Sign On (SSO) is working properly using forms authentication. Based on the users permissions when logging in a menu that lists their available applications and a logout link will be generated and saved in the cache - this menu displays fine whenever the user is in the SecurityApp (editing their profile) but we cannot figure out how to get the Applications in the virtual directories to display the same application menu. We have tried: 1) Using JSONP to do an request that will return the html for the menu. The ajax call returns the HTML with the html; however, because User.IsAuthenticated is false the menu comes back empty. 2) We created a user control and include it along with the dll's for the SecurityApp project and this works; however, we dont want to have to include all the dlls for the SecurityApp project in every application that we create (along with all the app settings in the web.config) We would like this to be as simple as possible to implement so that anyone creating a new app can add the menu to their application in as few steps as possible... Any ideas? To Clarify - we are using ASP.NET MVC 1.0 since these apps are in production and we do not have the okay to go to ASP.NET MVC 2.0 (unfortunately)

    Read the article

  • How to order a HasMany collection by a child property with Fluent NHibernate mapping

    - by Geoff Hardy
    I am using Fluent NHibernate to map the following classes: public abstract class DomainObject { public virtual int Id { get; protected internal set; } } public class Attribute { public virtual string Name { get; set; } } public class AttributeRule { public virtual Attribute Attribute { get; set; } public virtual Station Station { get; set; } public virtual RuleTypeId RuleTypeId { get; set; } } public class Station : DomainObject { public virtual IList<AttributeRule> AttributeRules { get; set; } public Station() { AttributeRules = new List<AttributeRule>(); } } My Fluent NHibernate mappings look like this: public class AttributeMap : ClassMap<Attribute> { public AttributeMap() { Id(o => o.Id); Map(o => o.Name); } } public class AttributeRuleMap : ClassMap<AttributeRule> { public AttributeRuleMap() { Id(o => o.Id); Map(o => o.RuleTypeId); References(o => o.Attribute).Fetch.Join(); References(o => o.Station); } } public class StationMap : ClassMap<Station> { public StationMap() { Id(o => o.Id); HasMany(o => o.AttributeRules).Inverse(); } } I would like to order the AttributeRules list on Station by the Attribute.Name property, but doing the following does not work: HasMany(o => o.AttributeRules).Inverse().OrderBy("Attribute.Name"); I have not found a way to do this yet in the mappings. I could create a IQuery or ICriteria to do this for me, but ideally I would just like to have the AttributeRules list sorted when I ask for it. Any advice on how to do this mapping?

    Read the article

  • InApp Purchase supported content types

    - by Chandan Shetty SP
    In InApp purchase guide i saw these are the supported content types - Digital Books,Virtual poker chips current games, In-game tool or accessory, etc... And non-supported - Physical books, Virtual poker chips for other games, In-game credits for virtual goods, etc... I didn't understand "In-game credits for virtual goods" what is this? In my game i am using some credits to skip certain levels, if credits are not available user can buy credits through inApp purchase then he can skip level... Is it valid supported content type for In-App purchase?

    Read the article

  • Axis2 Webservice -> php

    - by Peter Hagström
    Hi! If I have understood Axis2 correct i can construct a WebService and then access it with any SOAP compatible client. I have a java class with a couple of methods that I have written in Eclipse, and then automatically constructed a service with the Axis2 plugin from WTP. This is the methods of my class. public int test(int i){ return i+2; } public Car CarTest(int speed){ return new Car("Biltest", speed); } public CarFactoryAdapter getCarFactory(){ carFact.getCars().add(new Car("Bmw", 250)); carFact.getCars().add(new Car("seat", 350)); carFact.getCars().add(new Car("saab", 150)); carFact.getCars().add(new Car("volv", 50)); return new CarFactoryAdapter(carFact); } The code seems to work when I try it with soapUI and the Axis2-web interface has recognized the methods of my service. But when Iam trying the methods that receives parameters with PHP´s built in soapClient i get a Unknown exception. The getCarFactory methods works at least as expected, but it seems kind of crippled if I can´t send parameters. Example of non working method invocation. ini_set('soap.wsdl_cache_ttl',0); $client = new SoapClient("http://192.168.128.162:8080/ComplexWebService/services/CarService?wsdl", array('soap_version' => SOAP_1_2, 'trace' => 1)); $ar['i'] = (int)100; print_r($client->__soapCall("test",$ar)); I need to make sure that the SOA framework i choose will be able to comunicate with many platforms, there will be clients in at least PHP and Java, but it would be good if it will work in for example .NET to.

    Read the article

  • FluentNHibernate Many-To-One References where Foreign Key is not to Primary Key and column names are

    - by Todd Langdon
    I've been sitting here for an hour trying to figure this out... I've got 2 tables (abbreviated): CREATE TABLE TRUST ( TRUSTID NUMBER NOT NULL, ACCTNBR VARCHAR(25) NOT NULL ) CONSTRAINT TRUST_PK PRIMARY KEY (TRUSTID) CREATE TABLE ACCOUNTHISTORY ( ID NUMBER NOT NULL, ACCOUNTNUMBER VARCHAR(25) NOT NULL, TRANSAMT NUMBER(38,2) NOT NULL POSTINGDATE DATE NOT NULL ) CONSTRAINT ACCOUNTHISTORY_PK PRIMARY KEY (ID) I have 2 classes that essentially mirror these: public class Trust { public virtual int Id {get; set;} public virtual string AccountNumber { get; set; } } public class AccountHistory { public virtual int Id { get; set; } public virtual Trust Trust {get; set;} public virtual DateTime PostingDate { get; set; } public virtual decimal IncomeAmount { get; set; } } How do I do the many-to-one mapping in FluentNHibernate to get the AccountHistory to have a Trust? Specifically, since it is related on a different column than the Trust primary key of TRUSTID and the column it is referencing is also named differently (ACCTNBR vs. ACCOUNTNUMBER)???? Here's what I have so far - how do I do the References on the AccountHistoryMap to Trust??? public class TrustMap : ClassMap<Trust> { public TrustMap() { Table("TRUST"); Id(x => x.Id).Column("TRUSTID"); Map(x => x.AccountNumber).Column("ACCTNBR"); } } public class AccountHistoryMap : ClassMap<AccountHistory> { public AccountHistoryMap() { Table("TRUSTACCTGHISTORY"); Id (x=>x.Id).Column("ID"); References<Trust>(x => x.Trust).Column("ACCOUNTNUMBER").ForeignKey("ACCTNBR").Fetch.Join(); Map(x => x.PostingDate).Column("POSTINGDATE"); ); I've tried a few different variations of the above line but can't get anything to work - it pulls back AccountHistory data and a proxy for the Trust; however it says no Trust row with given identifier. This has to be something simple. Anyone? Thanks in advance.

    Read the article

  • Make is more OOPey - good structure?

    - by Tom
    Hi, I just want advice on whether I could improve structure around a particular class which handles all disk access functions The structure of my program is that I have a class called Disk which gets data from flatfiles and databases on a, you guessed it, hard disk drive. I have functions like LoadTextFileToStringList, WriteStringToTextFile, DeleteLineInTextFile etc which are kind of "generic methods" In the same class I also have some more specific methods such as GetXFromDisk where X might be a particular field in a database table/query. Should I separate out the generic methods from the specialised. Should I make another class which inherits the generic methods. At the moment my class is static as there is no need to have an internal state of the class. I'm not really OOPing am I? Thanks Thomas

    Read the article

  • iPad: Detecting External Keyboard

    - by StuartW
    My app uses a UIAccessoryView to provide additional keyboard functionality (such as forward/backward tabs and arrows keys) for the virtual keyboard, but that causes UIKeyboardDidShowNotification to fire even when a physical keyboard is present (the accessory appears at the bottom of the screen). I'd like to check if a physical keyboard is attached when handling UIKeyboardWillShowNotification, to prevent the accessory view from appearing and to prevent my custom view from scrolling up (to make room for the non-existent virtual keyboard). I've tried examining the UIKeyboardFrameEndUserInfoKey key, but it returns a real size for the virtual keyboard, in spite of nothing being displayed. Is there any way to detect the presence of a physical keyboard to prevent this unwanted behaviour? Hmm, the plot thickens. I tried disabling the input accessory by returning nil from the inputAccessoryView property of the Responder object which triggers the keyboard. That suppresses UIKeyboardWillShowNotification and UIKeyboardDidShowNotification when there is a physical keyboard present, but keeps these notifications when there is no such keyboard. All good so far. Then I tried re-enabling inputAccessoryView only after UIKeyboardWillShowNotification had been received. This only fires when a virtual keyboard is needed, so it should allow me to reintroduce the accessory view in those circumstances. Or so I thought. Unfortunately, it seems the OS doesn't check inputAccessoryView after UIKeyboardWillShowNotification, so it fails to show the accessory view when it is needed :o( That leaves me with two options: Include the input accessory view, giving extra functionality for virtual keyboard users, but lose the ability to detect a physical keyboard and hence not supporting physical devices; or Exclude the input accessory altogether, preventing most users from accessing the extra keys, but allowing the app to work with a physical keyboard. Not a great choice, so I'm still keen to see if anyone else has addressed this problem!

    Read the article

  • Is it possible to embed Cockburn style textual UML Use Case content in the code base to improve code

    - by fooledbyprimes
    experimenting with Cockburn use cases in code I was writing some complicated UI code. I decided to employ Cockburn use cases with fish,kite,and sea levels (discussed by Martin Fowler in his book 'UML Distilled'). I wrapped Cockburn use cases in static C# objects so that I could test logical conditions against static constants which represented steps in a UI workflow. The idea was that you could read the code and know what it was doing because the wrapped objects and their public contants gave you ENGLISH use cases via namespaces. Also, I was going to use reflection to pump out error messages that included the described use cases. The idea is that the stack trace could include some UI use case steps IN ENGLISH.... It turned out to be a fun way to achieve a mini,psuedo light-weight Domain Language but without having to write a DSL compiler. So my question is whether or not this is a good way to do this? Has anyone out there ever done something similar? c# example snippets follow Assume we have some aspx page which has 3 user controls (with lots of clickable stuff). User must click on stuff in one particular user control (possibly making some kind of selection) and then the UI must visually cue the user that the selection was successful. Now, while that item is selected, the user must browse through a gridview to find an item within one of the other user controls and then select something. This sounds like an easy thing to manage but the code can get ugly. In my case, the user controls all sent event messages which were captured by the main page. This way, the page acted like a central processor of UI events and could keep track of what happens when the user is clicking around. So, in the main aspx page, we capture the first user control's event. using MyCompany.MyApp.Web.UseCases; protected void MyFirstUserControl_SomeUIWorkflowRequestCommingIn(object sender, EventArgs e) { // some code here to respond and make "state" changes or whatever // // blah blah blah // finally we have this (how did we know to call fish level method?? because we knew when we wrote the code to send the event in the user control) UpdateUserInterfaceOnFishLevelUseCaseGoalSuccess(FishLevel.SomeNamedUIWorkflow.SelectedItemForPurchase) } protected void UpdateUserInterfaceOnFishLevelGoalSuccess(FishLevel.SomeNamedUIWorkflow goal) { switch (goal) { case FishLevel.SomeNamedUIWorkflow.NewMasterItemSelected: //call some UI related methods here including methods for the other user controls if necessary.... break; case FishLevel.SomeNamedUIWorkFlow.DrillDownOnDetails: //call some UI related methods here including methods for the other user controls if necessary.... break; case FishLevel.SomeNamedUIWorkFlow.CancelMultiSelect: //call some UI related methods here including methods for the other user controls if necessary.... break; // more cases... } } } //also we have protected void UpdateUserInterfaceOnSeaLevelGoalSuccess(SeaLevel.SomeNamedUIWorkflow goal) { switch (goal) { case SeaLevel.CheckOutWorkflow.ChangedCreditCard: // do stuff // more cases... } } } So, in the MyCompany.MyApp.Web.UseCases namespace we might have code like this: class SeaLevel... class FishLevel... class KiteLevel... The workflow use cases embedded in the classes could be inner classes or static methods or enumerations or whatever gives you the cleanest namespace. I can't remember what I did originally but you get the picture.

    Read the article

  • Why is creating a ring buffer shared by different processes so hard (in C++), what I am doing wrong?

    - by recipriversexclusion
    I am being especially dense about this but it seems I'm missing an important, basic point or something, since what I want to do should be common: I need to create a fixed-size ring buffer object from a manager process (Process M). This object has write() and read() methods to write/read from the buffer. The read/write methods will be called by independent processes (Process R and W) I have implemented the buffer, SharedBuffer<T&>, it allocates buffer slots in SHM using boost::interprocess and works perfectly within a single process. I have read the answers to this question and that one on SO, as well as asked my own, but I'm still in the dark about how to have different processes access methods from a common object. The Boost doc has an example of creating a vector in SHM, which is very similar to what I want, but I want to instantiate my own class. My current options are: Use placement new, as suggested by Charles B. to my question; however, he cautions that it's not a good idea to put non-POD objects in SHM. But my class needs the read/write methods, how can I handle those? Add an allocator to my class definition, e.g. have SharedBuffer<T&, Alloc> and proceed similarly to the vector example given in boost. This sounds really complicated. Change SharedBuffer to a POD class, i.e. get rid of all the methods. But then how to synchronize reading and writing between processes? What am I missing? Fixed-length ring buffers are very common, so either this problem has a solution or else I'm doing something wrong.

    Read the article

  • State pattern: Why doesn't the context class implement or inherit the State abstract interface/class

    - by Ricket
    I'm reading about the State pattern. I have only just begun, so of course I begin by reading the entire Wikipedia article on it. I noticed that both of the examples in the article have some base abstract class or Java interface for a generic State's methods/functions. Then there are some states which inherit from the base and implement those methods/functions in different ways. Then there's a Context class which has a private member of type State and which, at any time, can be equal to an instance of one of the implementations. That context class also implements the same methods, and passes them onto the current state instance, and then has an additional method to change the state (or depending on design I understand the change of state could be a reaction to one of the implemented methods). Why doesn't this context class specifically "extend" or "implement" the generic State base class/interface?

    Read the article

  • Can a C# method chain be "too long"?

    - by ccornet
    Not in terms of readability, naturally, since you can always arrange the separate methods into separate lines. Rather, is it dangerous, for any reason, to chain an excessively large number of methods together? I use method chaining primarily to save space on declaring individual one-use variables, and traditionally using return methods instead of methods that modify the caller. Except for string methods, those I kinda chain mercilessly. In any case, I worry sometimes about the impact of using exceptionally long method chains all in one line. Let's say I need to update the value of one item based on someone's username. Unfortunately, the shortest method to retrieve the correct user looks something like the following. SPWeb web = GetWorkflowWeb(); SPList list2 = web.Lists["Wars"]; SPListItem item2 = list2.GetItemById(3); SPListItem item3 = item2.GetItemFromLookup("Armies", "Allied Army"); SPUser user2 = item2.GetSPUser("Commander"); SPUser user3 = user2.GetAssociate("Spouse"); string username2 = user3.Name; item1["Contact"] = username2; Everything with a 2 or 3 lasts for only one call, so I might condense it as the following (which also lets me get rid of a would-be-superfluous 1): SPWeb web = GetWorkflowWeb(); item["Contact"] = web.Lists["Armies"] .GetItemById(3) .GetItemFromLookup("Armies", "Allied Army") .GetSPUser("Commander") .GetAssociate("Spouse") .Name; Admittedly, it looks a lot longer when it is all in one line and when you have int.Parse(ddlArmy.SelectedValue.CutBefore(";#", false)) instead of 3. Nevertheless, this is one of the average lengths of these chains, and I can easily foresee some of exceptionally longer counts. Excluding readability, is there anything I should be worried about for these 10+ method chains? Or is there no harm in using really really long method chains?

    Read the article

  • Recommendations for a C++ polymorphic, seekable, binary I/O interface

    - by Trevor Robinson
    I've been using std::istream and ostream as a polymorphic interface for random-access binary I/O in C++, but it seems suboptimal in numerous ways: 64-bit seeks are non-portable and error-prone due to streampos/streamoff limitations; currently using boost/iostreams/positioning.hpp as a workaround, but it requires vigilance Missing operations such as truncating or extending a file (ala POSIX ftruncate) Inconsistency between concrete implementations; e.g. stringstream has independent get/put positions whereas filestream does not Inconsistency between platform implementations; e.g. behavior of seeking pass the end of a file or usage of failbit/badbit on errors Don't need all the formatting facilities of stream or possibly even the buffering of streambuf streambuf error reporting (i.e. exceptions vs. returning an error indicator) is supposedly implementation-dependent in practice I like the simplified interface provided by the Boost.Iostreams Device concept, but it's provided as function templates rather than a polymorphic class. (There is a device class, but it's not polymorphic and is just an implementation helper class not necessarily used by the supplied device implementations.) I'm primarily using large disk files, but I really want polymorphism so I can easily substitute alternate implementations (e.g. use stringstream instead of fstream for unit tests) without all the complexity and compile-time coupling of deep template instantiation. Does anyone have any recommendations of a standard approach to this? It seems like a common situation, so I don't want to invent my own interfaces unnecessarily. As an example, something like java.nio.FileChannel seems ideal. My best solution so far is to put a thin polymorphic layer on top of Boost.Iostreams devices. For example: class my_istream { public: virtual std::streampos seek(stream_offset off, std::ios_base::seekdir way) = 0; virtual std::streamsize read(char* s, std::streamsize n) = 0; virtual void close() = 0; }; template <class T> class boost_istream : public my_istream { public: boost_istream(const T& device) : m_device(device) { } virtual std::streampos seek(stream_offset off, std::ios_base::seekdir way) { return boost::iostreams::seek(m_device, off, way); } virtual std::streamsize read(char* s, std::streamsize n) { return boost::iostreams::read(m_device, s, n); } virtual void close() { boost::iostreams::close(m_device); } private: T m_device; };

    Read the article

  • When to use a module, and when to use a class

    - by Matt Briggs
    I am currently working through the Gregory Brown Ruby Best Practices book. Early on, he is talking about refactoring some functionality from helper methods on a related class, to some methods on module, then had the module extend self. Hadn't seen that before, after a quick google, found out that extend self on a module lets methods defined on the module see each other, which makes sense. Now, my question is when would you do something like this module StyleParser extend self def process(text) ... end def style_tag?(text) ... end end and then refer to it in tests with @parser = Prawn::Document::Text::StyleParser as opposed to just using a class with some class methods on it? is it so that you can use it as a mixin? or are there other reasons I'm not seeing?

    Read the article

  • NHibernate : delete error

    - by MadSeb
    Hi, Model: I have a model in which one Installation can contain multiple "Computer Systems". Database: The table Installations has two columns Name and Description. The table ComputerSystems has three columsn Name, Description and InstallationId. Mappings: I have the following mapping for Installation: <?xml version="1.0" encoding="utf-8"?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="myProgram.Core" namespace="myProgram"> <class name="Installation" table="Installations" lazy="true"> <id name="Id" column="Id" type="int"> <generator class="native" /> </id> <property name="Name" column="Name" type="string" not-null="true" /> <property name="Description" column="Description" type="string" /> <bag name="ComputerSystems" inverse="true" lazy="true" cascade="all-delete-orphan"> <key column="InstallationId" /> <one-to-many class="ComputerSystem" /> </bag> </class> </hibernate-mapping> I have the following mapping for ComputerSystem: <?xml version="1.0" encoding="utf-8"?> <id name="Id" column="ID" type="int"> <generator class="native" /> </id> <property name="Name" column="Name" type="string" not-null="true" /> <property name="Description" column="Description" type="string" /> <many-to-one name="Installation" column="InstallationID" cascade="save-update" not-null="true" /> Classes: The Installation class is: public class Installation { public virtual String Description { get; set; } public virtual String Name { get; set; } public virtual IList<ComputerSystem> ComputerSystems { get { if (_computerSystemItems== null) { lock (this) { if (_computerSystemItems== null) _computerSystemItems= new List<ComputerSystem>(); } } return _computerSystemItems; } set { _computerSystemItems= value; } } protected IList<ComputerSystem> _computerSystemItems; public Installation() { Description = ""; Name= ""; } } The ComputerSystem class is: public class ComputerSystem { public virtual String Name { get; set; } public virtual String Description { get; set; } public virtual Installation Installation { get; set; } } The issue is that I get an error when trying to delete an installation that contains a ComputerSystem. The error is: "deleted object would be re-saved by cascade (remove deleted object from associations)". Can anyone help ? Regards, Seb

    Read the article

  • Rails: Overriding ActiveRecord association method

    - by seaneshbaugh
    Is there a way to override one of the methods provided by an ActiveRecord association? Say for example I have the following typical polymorphic has_many :through association: class Story < ActiveRecord::Base has_many :taggings, :as => :taggable has_many :tags, :through => :taggings, :order => :name end class Tag < ActiveRecord::Base has_many :taggings, :dependent => :destroy has_many :stories, :through => :taggings, :source => :taggable, :source_type => "Story" end As you probably know this adds a whole slew of associated methods to the Story model like tags, tags<<, tags=, tags.empty?, etc. How do I go about overriding one of these methods? Specifically the tags<< method. It's pretty easy to override a normal class methods but I can't seem to find any information on how to override association methods. Doing something like def tags<< *new_tags #do stuff end produces a syntax error when it's called so it's obviously not that simple.

    Read the article

  • subdomain in glassfish

    - by Pradyut Bhattacharya
    Hi I want to set up a virtual server for subdomain my domain is redirected from pradyut.dyndns.org to pradyut.dyndns.org/WebApplicationSecurity using a virtual server whose default web module is WebApplicationSecurity I have used the string "${com.sun.aas.hostName},pradyut.dyndns.org" in the hosts of the virtual server now to the question if someone enters "newa.pradyut.dyndns.org" how can i redirect to pradyut.dyndns.org/WebApplicationSecurity/newa or "*.pradyut.dyndns.org" redirects to "pradyut.dyndns.org/WebApplicationSecurity/*" Thanks Pradyut

    Read the article

  • C# Hiding, overriding and calling function from base class.

    - by Lukasz Lysik
    I'm learning C# and I encountered the following problem. I have two classes: base and derived: class MyBase { public void MyMethod() { Console.WriteLine("MyBase::MyMethod()"); } } class MyDerived: MyBase { public void MyMethod() { Console.WriteLine("MyDerived::MyMethod()"); } } For now, without virtual and override key words. When I compile this I get the warning (which is of course expected) that I try to hide MyMethod from MyBase class. What I want to do is to call the method from the base class having an instance of derived class. I do this like this: MyDerived myDerived = new MyDerived(); ((MyBase)myDerived).MyMethod(); It works fine when I do not specify any virtual, etc. keywords in the methods. I tried to put combination of the keywords and I got the following results: | MyBase::MyMethod | MyDerived::MyMethod | Result printed on the console | | -----------------|---------------------|-------------------------------| | - | - | MyBase::MyMethod() | | - | new | MyBase::MyMethod() | | virtual | new | MyBase::MyMethod() | | virtual | override | MyDerived::MyMethod() | I hope the table is clear to you. I have two questions: Is it the correct way to call the function from the base class (((MyBase)myDerived).MyMethod();)? I know about base keyword, but it can be called only from the inside of the derived class. Is it right? Why in the last case (with virtual and override modifiers) the method which was called came from the derived class? Would you please explain that?

    Read the article

  • Interface vs Abstract Class (general OO)

    - by Kave
    Hi, I have had recently two telephone interviews where I've been asked about the differences between an Interface and an Abstract class. I have explained every aspect of them I could think of, but it seems they are waiting for me to mention something specific, and I dont know what it is. From my experience I think the following is true, if i am missing a major point please let me know: Interface: Every single Method declared in an Interface will have to be implemented in the subclass. Only Events, Delegates, Properties (C#) and Methods can exist in a Interface. A class can implement multiple Interfaces. Abstract Class Only Abstract methods have to be implemented by the subclass. An Abstract class can have normal methods with implementations. Abstract class can also have class variables beside Events, Delegates, Properties and Methods. A class can only implement one abstract class only due non-existence of Multi-inheritance in C#. 1) After all that the interviewer came up with the question What if you had an Abstract class with only abstract methods, how would that be different from an interface? I didnt know the answer but I think its the inheritance as mentioned above right? 2) An another interviewer asked me what if you had a Public variable inside the interface, how would that be different than in Abstract Class? I insisted you can't have a public variable inside an interface. I didn't know what he wanted to hear but he wasn't satisfied either. Many Thanks for clarification, Kave See Also: When to use an interface instead of an abstract class and vice versa Interfaces vs. Abstract Classes How do you decide between using an Abstract Class and an Interface?

    Read the article

  • When should I open and close a connection to SQL Server

    - by Martin
    I have a simple static class with a few methods in it. Each of those methods open a SqlConnection, query the database and close the connection. This way, I am sure that I always close the connection to the database, but on the other hand, I don't like to always open and close connection. Below is an example of what my methods look like. public static void AddSomething(string something) { using (SqlConnection connection = new SqlConnection("...")) { connection.Open(); // ... connection.Close(); } } Considering that the methods are inside a static class, should I have a static member containing a single SqlConnection? How and when should I drop it? What are the best practices?

    Read the article

< Previous Page | 188 189 190 191 192 193 194 195 196 197 198 199  | Next Page >