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  • Is there anything bad in declaring static inner class inside interface in java?

    - by Roman
    I have an interface ProductService with method findByCriteria. This method had a long list of nullable parameters, like productName, maxCost, minCost, producer and so on. I refactored this method by introducing Parameter Object. I created class SearchCriteria and now method signature looks like this: findByCriteria (SearchCriteria criteria) I thought that instances of SearchCriteria are only created by method callers and are only used inside findByCriteria method, i.e.: void processRequest() { SearchCriteria criteria = new SearchCriteria () .withMaxCost (maxCost) ....... .withProducer (producer); List<Product> products = productService.findByCriteria (criteria); .... } and List<Product> findByCriteria(SearchCriteria criteria) { return doSmthAndReturnResult(criteria.getMaxCost(), criteria.getProducer()); } So I did not want to create separate public class for SearchCriteria and put it inside ProductServiceInterface: public interface ProductService { List<Product> findByCriteria (SearchCriteria criteria); static class SearchCriteria { ... } } Is there anything bad in this interface? Where whould you place SearchCriteria class?

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  • Do all the HTML5 storage systems work together ?

    - by azera
    While there are a lot of good stuff about html5, one thing I don't get is the redondant storage mechanism, first there is localstorage and sessionstorage, which are key value stores, one is for one instance of the app ("one tab"), and the other works for all the instances of that application so they can share data. Both are saved when you close your browser and have a limited size (usually 5MB), that's great and everything would be nice if we stopped there. But then there is the "Web SQL Database", which has the same security system as the localstorage, the same size limit, the same everything except it works like/is sqlite, with tables and sql syntax and all of that. And the bummer is, they don't work on the same data at all ! This is not two way to access your data, this is really two storage for every html 5 app out there (not created by default yes, but still you see my point). What I would like to know is, is there a reason for both of this mechanisms to exist at the same time ? Or did they just look at sql and nosql movement to pick the best then went "screw it let's add both !" ? Why not implement local/session storage as a table inside web sql db ?

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  • Square Brackets in Python Regular Expressions (re.sub)

    - by user1479984
    I'm migrating wiki pages from the FlexWiki engine to the FOSwiki engine using Python regular expressions to handle the differences between the two engines' markup languages. The FlexWiki markup and the FOSwiki markup, for reference. Most of the conversion works very well, except when I try to convert the renamed links. Both wikis support renamed links in their markup. For example, Flexwiki uses: "Link To Wikipedia":[http://www.wikipedia.org/] FOSwiki uses: [[http://www.wikipedia.org/][Link To Wikipedia]] both of which produce something that looks like I'm using the regular expression renameLink = re.compile ("\"(?P<linkName>[^\"]+)\":\[(?P<linkTarget>[^\[\]]+)\]") to parse out the link elements from the FlexWiki markup, which after running through something like "Link Name":[LinkTarget] is reliably producing groups <linkName> = Link Name <linkTarget = LinkTarget My issue occurs when I try to use re.sub to insert the parsed content into the FOSwiki markup. My experience with regular expressions isn't anything to write home about, but I'm under the impression that, given the groups <linkName> = Link Name <linkTarget = LinkTarget a line like line = renameLink.sub ( "[[\g<linkTarget>][\g<linkName>]]" , line ) should produce [[LinkTarget][Link Name]] However, in the output to the text files I'm getting [[LinkTarget [[Link Name]] which breaks the renamed links. After a little bit of fiddling I managed a workaround, where line = renameLink.sub ( "[[\g<linkTarget>][ [\g<linkName>]]" , line ) produces [[LinkTarget][ [[Link Name]] which, when displayed in FOSwiki looks like <[[Link Name> <--- Which WORKS, but isn't very pretty. I've also tried line = renameLink.sub ( "[[\g<linkTarget>]" + "[\g<linkName>]]" , line ) which is producing [[linkTarget [[linkName]] There are probably thousands of instances of these renamed links in the pages I'm trying to convert, so fixing it by hand isn't any good. For the record I've run the script under Python 2.5.4 and Python 2.7.3, and gotten the same results. Am I missing something really obvious with the syntax? Or is there an easy workaround?

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  • Using JQuery in an AJAX control and avoiding conflicts

    - by Rich Andrews
    Hi, I am using JQuery within a custom AJAX user control (part of a home grown toolkit) and I need to ensure that JQuery is present on the hosting page. There can be multiple instances of the control on a page and some controls may need to use different versions of JQuery. At the moment I am using the following code to load in JQuery when the control initializes... Page.ClientScript.RegisterClientScriptInclude(Page.GetType(), "jquery-1.4.4.min.js", this.ResolveUrl("TextControlPlugin/lib/jquery-1.4.4.min.js")); This works because the scriptmanager handles not putting multiple copies of the same script into he page. Problems... I cannot use JQuery statically in the calling page (I may not have a control on the page but need to use JQuery) The scriptmanager appears to handle only duplicate URL's and I will need to deploy it from potentially 2 different URL's (the calling page's copy and the controls copy) So, is there a way to isolate a version of JQuery to the context of my control that doesnt interfear with any use of JQuery from the calling page? The developer writing the page may not have access to the internals of the control. I have looked at JQuery.noConflict() but cannot seem to get it to work correctly - I believe I'm having problems with the order in which the scripts are injected into the page - I keep getting JQuery is undefined errors. Any help would be much appreciated

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  • Host WCF in MVC2 Site

    - by Basiclife
    Hi, We've got a very large, complex MVC2 website. We want to add an API for some internal tools and decided to use WCF. Ideally, we want MVC itself to host the WCF service. Reasons include: Although there's multiple tiers to the application, some functionality we'd like in the API requires the website itself (e.g. formatting emails). We use TFS to auto-build (continuous integration) and deploy - The less we need to modify the build and release mechanism the better We use the Unity container and Inversion of Control throughout the application. Being part of the Website would allow us to re-use configuration classes and other helper methods. I've written a custom ServiceBehavior which in turn has a custom InstanceProvider - This allows me to instantiate and configure a container which is then used to service all requests for class instances from WCF. So my question is; Is it possible to host a WCF service from within MVC itself? I've only had experience in Services / Standard Asp.Net websites before and didn't realise MVC2 might be different until I actually tried to wire it into the config and nothing happened. After some googling, there don't seem to be many references to doing this - so thought I'd ask here.

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  • Dealing With Java Default Level Access Specifiers

    - by Tom Tresansky
    I've seen some code in a project recently where some fields in a couple classes have been using the default access modifier without good reason to. It almost looks like a case of "oops, forgot to make these private". Since the classes are used almost exclusively outside of the package they are defined in, the fields are not visible from the calling code, and are treated as private. So the mistake/oversight would not be very noticeable. However, encapsulation is broken. If I wanted to add a new class to the existing package, I could then mess with internal data in objects using fields with default access. So, my questions: Are there any best practices concerning default access specifiers that I should be aware of? Anything that would help prevent this type of accident from re-occurring? Are are any annotations which might say something to the effect of "I really meant for these to be default access"? Using CheckStyle, or any other Eclipse plugins, is there any way to flag instances of default fields, or disallow any not accompanied by, say, a "//default access" comment trailing them?

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  • How to determine which inheriting class is using an abstract class's methods.

    - by Kin
    In my console application have an abstract Factory class "Listener" which contains code for listening and accepting connections, and spawning client classes. This class is inherited by two more classes (WorldListener, and MasterListener) that contain more protocol specific overrides and functions. I also have a helper class (ConsoleWrapper) which encapsulates and extends System.Console, containing methods for writing to console info on what is happening to instances of the WorldListener and MasterListener. I need a way to determine in the abstract ListenerClass which Inheriting class is calling its methods. Any help with this problem would be greatly appreciated! I am stumped :X Simplified example of what I am trying to do. abstract class Listener { public void DoSomething() { if(inheriting class == WorldListener) ConsoleWrapper.WorldWrite("Did something!"); if(inheriting class == MasterListener) ConsoleWrapper.MasterWrite("Did something!"); } } public static ConsoleWrapper { public void WorldWrite(string input) { System.Console.WriteLine("[World] {0}", input); } } public class WorldListener : Listener { public void DoSomethingSpecific() { ConsoleWrapper.WorldWrite("I did something specific!"); } } public void Main() { new WorldListener(); new MasterListener(); } Expected output [World] Did something! [World] I did something specific! [Master] Did something! [World] I did something specific!

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  • In which domains are message oriented middleware like AMQP useful?

    - by cocotwo
    What problem do MOM (Message Oriented Middleware) solve? Scalability? Integration? In which domain are they typically used and in which domains are they typically not used? For example, say, is Google using such solution for it's main search engine or to power GMail? What about big websites like Walmart, eBay, FedEx (pretty much a Java shop) and buy.com (pretty much an MS shop)? Does MOM solve a need there? Does it make any sense when you're writing a Webapp where you control the server-side and have an homogenous environment (say tens of Amazon EC2 instances all running Linux + Java JVMs) there and where the clients are, well, Web browsers? Does it make sense for desktop apps that need to communicate with a server? Or is it 'only' for big enterprise stuff where you typically have a happy mix of countless of different systems that needs to communicate in a way or another? I'm a bit confused as to what they're useful for and I think that with example of where they're appropriate and where they're not appropriate I could better understand their use.

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  • Are bad data issues that common?

    - by Water Cooler v2
    I've worked for clients that had a large number of distinct, small to mid-sized projects, each interacting with each other via properly defined interfaces to share data, but not reading and writing to the same database. Each had their own separate database, their own cache, their own file servers/system that they had dedicated access to, and so they never caused any problems. One of these clients is a mobile content vendor, so they're lucky in a way that they do not have to face the same problems that everyday business applications do. They can create all those separate compartments where their components happily live in isolation of the others. However, for many business applications, this is not possible. I've worked with a few clients, one of whose applications I am doing the production support for, where there are "bad data issues" on an hourly basis. Yeah, it's that crazy. Some data records from one of the instances (lower than production, of course) would have been run a couple of weeks ago, and caused some other user's data to get corrupted. And then, a data script will have to be written to fix this issue. And I've seen this happening so much with this client that I have to ask. I've seen this happening at a moderate rate with other clients, but this one just seems to be out of order. If you're working with business applications that share a large amount of data by reading and writing to/from the same database, are "bad data issues" that common in your environment?

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  • Debugged Program Window Won't Close

    - by Marc Bernier
    Hi, I'm using VS 2008 on a 64-bit XP machine. I'm debugging a 32-bit C++ DLL via a console program. The DLL and EXE projects are contained in the same SLN so that I can modify the DLL as I test. What happens is that every once in a while I kill the program with Debug | Stop Debugging (Shift-F5). VS stops the program, but the console window stays open! If I'm sitting at a breakpoint and hit Shift-F5, it will terminate properly, but if the program is running full-tilt when I stop it, I often see this instead. The big problem is that I can't close these zombie windows. Using End Task in Task Manager does nothing (no message, no nothing). When I shut down the machine, it is unable to due to the orphans and I have to resort to actually turning off the power. I think this is connected to having the DLL and EXE project in the same SLN, as for months I worked on this project in 2 VS instances, one for the DLL and the other for the EXE. I would continually jump back and forth between the windows as I worked. This problem never happened until I put the two projects into a single SLN. The single SLN works a lot better, but this anomaly is very irritating. Any ideas anyone? UPDATE After a bit of searching (here), I found that it appears to have to do with one of the updates from last Tuesday (KB977165 or KB978037). Thank you Microsoft for your excellent pre-release testing.

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  • Deployment of SQL Server: installing a second instance?

    - by Workshop Alex
    Simple problem. I'm working on a Delphi 2007/WIN32 application which now uses MS Access as simple data store. I have to modify it to support SQL Server Express, which is easy. These modifications are working so the application can be deployed using either SQL Server or MS Access. (Whatever the user prefers.) I did consider deploying the whole application together with the SQL Compact but this is not practicak. Using SQL Server Express 2008 instead of 2005 is an option, but also has a few nasty side-effects which we don't want to resolve for now. The problem is deploying the whole project. The installation with SQL Server would need a quiet installation so the user won't notice it. SQL Server is mentioned in the documentation so they know it's there. We just don't want to bother them with technical issues. In most cases, such an installation will go just fine. But what if the user already has an SQL Server (2005) installation which is used for something else? Personally, I would prefer to just install a second instance of SQL Server on their system so it won't conflict with the other installation. (Thus, if they uninstall the other app, the SQL instance will just stay installed.) While SQL Server 2005 and 2008 can be installed on the same system simply by using two different names for the instance, I wonder if it's also possible to install SQL Server 2005 twice on a single system to get two instances. And if possible, how?

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  • How to get an embedded function to run multiple times

    - by Guy Montag
    The question I have is how to I get multiple instances of a function to run. Here is my function below - A simple fade function. Problem I'm having is that when it is called a second time it abandons the first call. So if a user clicks on a button it will display a message which fades. If the user clicks on another button the previous fading message just stops at the current opacity level. Try it here - www.arcmarks.com ( please do not repost this domain name) click on SignUp and than quickly click on SignIn with out typing anything. You will see the previous message simply halts. ? What is the stopping mechanism? Where did the previous function go? The function function newEffects(element, direction, max_time ) { newEffects.arrayHold = []; newEffects.arrayHold[element.id] = 0; function next() { newEffects.arrayHold[element.id] += 10; if ( direction === 'up' ) { element.style.opacity = newEffects.arrayHold[element.id] / max_time; } else if ( direction === 'down' ) { element.style.opacity = ( max_time - newEffects.arrayHold[element.id] ) / max_time; } if ( newEffects.arrayHold[element.id] <= max_time ) { setTimeout( next, 10 ); } } next(); return true; }; The Call newEffects(this.element, 'down', 4000 );

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  • MEF instance management

    - by Lawrence A. Contreras
    I am working on application that has multiple modules and sub modules. Here's what I need to do: ModuleA has a sub module SubModuleA, SubModuleB, SubModuleC. I want to export ModuleA, SubModuleA, SubModuleB, SubModuleC. ModuleA can have multiple instances. Whenever I import ModuleA inside the sub modules, I want to get the correct instance and also when I import SubModuleA,SubModuleB and SubModuleC inside other classes. How can I manage that scenario using MEF? Do I really need to use MEF. Updated: Here's a quick example: public class School { List<Classroom> classRooms { get; set; } } [Export] public class Classroom { List<Teacher> teachers { get; set; } } public class Teacher { List<Student> students { get; set; } } public class Student { [Import] Classroom classroom { get; set; } } As you can see, I want to export the classroom class because I need to import it in the Student class, let's just say that I really need the classroom class inside the student class. I want to skip the part where we pass the classroom to the teacher and from the teacher we'll pass it to the student. But when I import classroom, I want to have the correct instance where that class room contains the teacher of the student.

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  • Python list should be empty on class instance initialisation, but it's not. Why?

    - by canavanin
    Hi everyone! I would like to create instances of a class containing a list that's empty by default; instead of later setting this list to the final full list I would like to successively add items to it. Here's a piece of sample code illustrating this: #!/usr/bin/python class test: def __init__(self, lst=[], intg=0): self.lista = lst self.integer = intg name_dict = {} counter = 0 for name in ('Anne', 'Leo', 'Suzy'): counter += 1 name_dict[name] = test() name_dict[name].integer += 1 name_dict[name].lista.append(counter) print name, name_dict[name].integer, name_dict[name].lista When I ran the above program I expected to get Anne 1 [1] Leo 1 [2] Suzy 1 [3] as I assumed lista to always be initialised to an empty list. What I got instead was this: Anne 1 [1] Leo 1 [1, 2] Suzy 1 [1, 2, 3] If I replace self.lista = lst by self.lista = [] it works fine, just like when I add the line name_dict[name].lista = [] to the for loop. Why is it that the contents of the previous objects' lists are retained, yet their values of integer aren't? I am rather new to Python, so it would be great if someone could point out to me where my thoughts/assumptions have gone astray. Thanks a lot in advance for your replies.

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  • Avoiding mass propagation of properties and events for exposure to ViewModels.

    - by firoso
    I have an MVVM application I am developing that is to the point where I'm ready to start putting together a user interface (my client code is largely functional) I'm now running into the issue that I'm trying to get my application data to where I need it so that it can be consumed by the view model and then bound to the view. Unfortunately, it seems that I've either got a few structural oversights, or I'm just going to have to face the reality that I need to be propogating events and raising excessive amounts of errors to notify view models that thier properties have changed. Let me go into some examples of my issue: I have a class "Unit" contained in a class "Test", contained in a class "Session" contained in a class "TestManager" which is contained in "TestDataModel" which is utilized by "TestViewModel" which is databound to by my "TestView" .... WHOA. Now, consider that Unit (the bottom of the heiarchy) has a property called "Results" that is updated periodically, I want to expose that to my viewmodel and then databind it to my view, trouble is, the only way I can really think to do this is to perpetuate events WAY up a chain that say "I've been updated!" and then request the new value... This seems like an aweful way to do this. Alternatively, I could register a static event and raise it, and have the appropriate "Unit view model" grab the event and request the update. This SEEMS better... but... static events? Is that a taboo idea? Also, having an expression like: TestDataModel.TestManager.Session.Test.Unit.Results[i] Seems REALLY gross to have on a View Model. I know this all reeks of a bad design issue, but I can't figure out what I did wrong? Should I be using more singleton/container controlled lifetimes type objects? Register object instances with static helper containers? Obviously these are hard questions to answer without being intimate with the existing structure, but if you've run into situations like this, what did you do to refactor? Should I just live with this, add mass events, and propogate them?

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  • Java abstract visitor - guarantueed to succeed? If so, why?

    - by disown
    I was dealing with hibernate, trying to figure out the run-time class behind proxied instances by using the visitor pattern. I then came up with an AbstractVisitable approach, but I wonder if it will always produce correct results. Consider the following code: interface Visitable { public void accept(Visitor v); } interface Visitor { public void visit(Visitable visitorHost); } abstract class AbstractVisitable implements Visitable { @Override public void accept(Visitor v) { v.visit(this); } } class ConcreteVisitable extends AbstractVisitable { public static void main(String[] args) { final Visitable visitable = new ConcreteVisitable(); final Visitable proxyVisitable = (Visitable) Proxy.newProxyInstance( Thread.currentThread().getContextClassLoader(), new Class<?>[] { Visitable.class }, new InvocationHandler() { @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { return method.invoke(visitable, args); } }); proxyVisitable.accept(new Visitor() { @Override public void visit(Visitable visitorHost) { System.out.println(visitorHost.getClass()); } }); } } This makes a ConcreteVisitable which inherits the accept method from AbstractVisitable. In c++, I would consider this risky, since this in AbstractVisitable could be referencing to AbstractVisitable::this, and not ConcreteVisitable::this. I was worried that the code under certain circumstances would print class AbstractVisible. Yet the code above outputs class ConcreteVisitable, even though I hid the real type behind a dynamic proxy (the most difficult case I could come up with). Is the abstract visitor approach above guaranteed to work, or are there some pitfalls with this approach? What guarantees are given in Java with respect to the this pointer?

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  • Can we have a component-scoped bean in a JSF2 composite component?

    - by Pradyumna
    Hi, I was wondering how I could create "component-scoped" beans, or so-to-say, "local variables inside a composite component" that are private to the instance of the composite component, and live as long as that instance lives. Below are more details, explained with an example: Suppose there is a "calculator" component - something that allows users to type in a mathematical expression, and evaluates its value. Optionally, it also plots the associated function. I can make a composite component that has: a text box for accepting the math expression two buttons called "Evaluate", and "Plot" another nested component that plots the function It is evidently a self-contained piece of function; so that somebody who wants to use it may just say <math:expressionEvaluator /> But obviously, the implementation would need a java object - something that evaluates the expression, something that computes the plot points, etc. - and I imagine it can be a bean - scoped just for this instance of this component, not a view-scoped or request-scoped bean that is shared across all instances of the component. How do I create such a bean? Is that even possible with composite components?

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  • MVVM and avoiding Monolithic God object

    - by bufferz
    I am in the completion stage of a large project that has several large components: image acquisition, image processing, data storage, factory I/O (automation project) and several others. Each of these components is reasonably independent, but for the project to run as a whole I need at least one instance of each component. Each component also has a ViewModel and View (WPF) for monitoring status and changing things. My question is the safest, most efficient, and most maintainable method of instantiating all of these objects, subscribing one class to an Event in another, and having a common ViewModel and View for all of this. Would it best if I have a class called God that has a private instance of all of these objects? I've done this in the past and regretted it. Or would it be better if God relied on Singleton instances of these objects to get the ball rolling. Alternatively, should Program.cs (or wherever Main(...) is) instantiate all of these components, and pass them to God as parameters and then let Him (snicker) and His ViewModel deal with the particulars of running this projects. Any other suggestions I would love to hear. Thank you!

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  • PHP OOP: Avoid Singleton/Static Methods in Domain Model Pattern

    - by sunwukung
    I understand the importance of Dependency Injection and its role in Unit testing, which is why the following issue is giving me pause: One area where I struggle not to use the Singleton is the Identity Map/Unit of Work pattern (Which keeps tabs on Domain Object state). //Not actual code, but it should demonstrate the point class Monitor{//singleton construction omitted for brevity static $members = array();//keeps record of all objects static $dirty = array();//keeps record of all modified objects static $clean = array();//keeps record of all clean objects } class Mapper{//queries database, maps values to object fields public function find($id){ if(isset(Monitor::members[$id]){ return Monitor::members[$id]; } $values = $this->selectStmt($id); //field mapping process omitted for brevity $Object = new Object($values); Monitor::new[$id]=$Object return $Object; } $User = $UserMapper->find(1);//domain object is registered in Id Map $User->changePropertyX();//object is marked "dirty" in UoW // at this point, I can save by passing the Domain Object back to the Mapper $UserMapper->save($User);//object is marked clean in UoW //but a nicer API would be something like this $User->save(); //but if I want to do this - it has to make a call to the mapper/db somehow $User->getBlogPosts(); //or else have to generate specific collection/object graphing methods in the mapper $UserPosts = $UserMapper->getBlogPosts(); $User->setPosts($UserPosts); Any advice on how you might handle this situation? I would be loathe to pass/generate instances of the mapper/database access into the Domain Object itself to satisfy DI - At the same time, avoiding that results in lots of calls within the Domain Object to external static methods. Although I guess if I want "save" to be part of its behaviour then a facility to do so is required in its construction. Perhaps it's a problem with responsibility, the Domain Object shouldn't be burdened with saving. It's just quite a neat feature from the Active Record pattern - it would be nice to implement it in some way.

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  • are there requirements for Struts setters beyond variable name matching?

    - by slk
    I have a model-driven Struts Web action: public class ModelDrivenAction<T extends Object> implements ModelDriven<T>, Preparable { protected Long id; protected T model; @Override public void prepare() {} public void setId(Long id) { this.id = id; } @Override public T getModel() { return model; } public void setModel(T model) { this.model = model; } } I have another action which is not currently model-driven: public class OtherAction implements Preparable { private ModelObj modelObj; private Long modelId; @Override public void prepare() { modelObj = repoService.retrieveModelById(modelId); } public void setModelId(Long modelId) { this.modelId = modelId; } } I wish to make it so, and would like to avoid having to track down all the instances in JavaScript where the action is passed a "modelId" parameter instead of "id" if at all possible. I thought this might work, so either modelId or id could be passed in: public class OtherAction extends ModelDrivenAction<ModelObj> { @Override public void prepare() { model = repoService.retrieveModelById(id); } public void setModelId(Long modelId) { this.id = modelId; } } However, server/path/to/other!method?modelId=123 is failing to set id. I thought so long as a setter matched a parameter name the Struts interceptor would call it on action invocation. Am I missing something here?

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  • Would an immutable keyword in Java be a good idea?

    - by berry120
    Generally speaking, the more I use immutable objects in Java the more I'm thinking they're a great idea. They've got lots of advantages from automatically being thread-safe to not needing to worry about cloning or copy constructors. This has got me thinking, would an "immutable" keyword go amiss? Obviously there's the disadvantages with adding another reserved word to the language, and I doubt it will actually happen primarily for the above reason - but ignoring that I can't really see many disadvantages. At present great care has to be taken to make sure objects are immutable, and even then a dodgy javadoc comment claiming a component object is immutable when it's in fact not can wreck the whole thing. There's also the argument that even basic objects like string aren't truly immutable because they're easily vunerable to reflection attacks. If we had an immutable keyword the compiler could surely recursively check and give an iron clad guarantee that all instances of a class were immutable, something that can't presently be done. Especially with concurrency becoming more and more used, I personally think it'd be good to add a keyword to this effect. But are there any disadvantages or implementation details I'm missing that makes this a bad idea?

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  • named type not used for constructor injection

    - by nmarun
    Hi, I have a simple console application where I have the following setup: public interface ILogger { void Log(string message); } class NullLogger : ILogger { private readonly string version; public NullLogger() { version = "1.0"; } public NullLogger(string v) { version = v; } public void Log(string message) { Console.WriteLine("NULL " + version + " : " + message); } } The configuration details are below: <type type="UnityConsole.ILogger, UnityConsole" mapTo="UnityConsole.NullLogger, UnityConsole"> My calling code looks as below: IUnityContainer container = new UnityContainer(); UnityConfigurationSection section = (UnityConfigurationSection)ConfigurationManager.GetSection("unity"); section.Containers.Default.Configure(container); ILogger nullLogger = container.Resolve(); nullLogger.Log("hello"); This works fine, but once I give a name to this type something like: <type type="UnityConsole.ILogger, UnityConsole" mapTo="UnityConsole.NullLogger, UnityConsole" name="NullLogger"> The above calling code does not work even if I explicitly register the type using container.RegisterType<ILogger, NullLogger>(); I get the error: {"Resolution of the dependency failed, type = \"UnityConsole.ILogger\", name = \"\". Exception message is: The current build operation (build key Build Key[UnityConsole.NullLogger, null]) failed: The parameter v could not be resolved when attempting to call constructor UnityConsole.NullLogger(System.String v). (Strategy type BuildPlanStrategy, index 3)"} Why doesn't unity look into named instances? To get it to work, I'll have to do: ILogger nullLogger = container.Resolve("NullLogger"); Where is this behavior documented? Arun

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  • Grails - Removing an item from a hasMany association List on data bind?

    - by ecrane
    Grails offers the ability to automatically create and bind domain objects to a hasMany List, as described in the grails user guide. So, for example, if my domain object "Author" has a List of many "Book" objects, I could create and bind these using the following markup (from the user guide): <g:textField name="books[0].title" value="the Stand" /> <g:textField name="books[1].title" value="the Shining" /> <g:textField name="books[2].title" value="Red Madder" /> In this case, if any of the books specified don't already exist, Grails will create them and set their titles appropriately. If there are already books in the specified indices, their titles will be updated and they will be saved. My question is: is there some easy way to tell Grails to remove one of those books from the 'books' association on data bind? The most obvious way to do this would be to omit the form element that corresponds to the domain instance you want to delete; unfortunately, this does not work, as per the user guide: Then Grails will automatically create a new instance for you at the defined position. If you "skipped" a few elements in the middle ... Then Grails will automatically create instances in between. I realize that a specific solution could be engineered as part of a command object, or as part of a particular controller- however, the need for this functionality appears repeatedly throughout my application, across multiple domain objects and for associations of many different types of objects. A general solution, therefore, would be ideal. Does anyone know if there is something like this included in Grails?

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  • Building "isolated" and "automatically updated" caches (java.util.List) in Java.

    - by Aidos
    Hi Guys, I am trying to write a framework which contains a lot of short-lived caches created from a long-living cache. These short-lived caches need to be able to return their entier contents, which is a clone from the original long-living cache. Effectively what I am trying to build is a level of transaction isolation for the short-lived caches. The user should be able to modify the contents of the short-lived cache, but changes to the long-living cache should not be propogated through (there is also a case where the changes should be pushed through, depending on the Cache type). I will do my best to try and explain: master-cache contains: [A,B,C,D,E,F] temporary-cache created with state [A,B,C,D,E,F] 1) temporary-cache adds item G: [A,B,C,D,E,F] 2) temporary-cache removes item B: [A,C,D,E,F] master-cache contains: [A,B,C,D,E,F] 3) master-cache adds items [X,Y,Z]: [A,B,C,D,E,F,X,Y,Z] temporary-cache contains: [A,C,D,E,F] Things get even harder when the values in the items can change and shouldn't always be updated (so I can't even share the underlying object instances, I need to use clones). I have implemented the simple approach of just creating a new instance of the List using the standard Collection constructor on ArrayList, however when you get out to about 200,000 items the system just runs out of memory. I know the value of 200,000 is excessive to iterate, but I am trying to stress my code a bit. I had thought that it might be able to somehow "proxy" the list, so the temporary-cache uses the master-cache, and stores all of it's changes (effectively a Memento for the change), however that quickly becomes a nightmare when you want to iterate the temporary-cache, or retrieve an item at a specific index. Also given that I want some modifications to the contents of the list to come through (depending on the type of the temporary-cache, whether it is "auto-update" or not) and I get completly out of my depth. Any pointers to techniques or data-structures or just general concepts to try and research will be greatly appreciated. Cheers, Aidos

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  • java: libraries for immutable functional-style data structures

    - by Jason S
    This is very similar to another question (Functional Data Structures in Java) but the answers there are not particularly useful. I need to use immutable versions of the standard Java collections (e.g. HashMap / TreeMap / ArrayList / LinkedList / HashSet / TreeSet). By "immutable" I mean immutable in the functional sense (e.g. purely functional data structures), where updating operations on the data structure do not change the original data, but instead return a new instance of the same kind of data structure. Also typically new and old instances of the data structure will share immutable data to be efficient in time and space. From what I can tell my options include: Functional Java Scala Clojure but I'm not sure whether any of these are particularly appealing to me. I have a few requirements/desirements: the collections in question should be usable directly in Java (with the appropriate libraries in the classpath). FJ would work for me; I'm not sure if I can use Scala's or Clojure's data structures in Java w/o having to use the compilers/interpreters from those languages and w/o having to write Scala or Clojure code. Core operations on lists/maps/sets should be possible w/o having to create function objects with confusing syntaxes (FJ looks slightly iffy) They should be efficient in time and space. I'm looking for a library which ideally has done some performance testing. FJ's TreeMap is based on a red-black tree, not sure how that rates. Documentation / tutorials should be good enough so someone can get started quickly using the data structures. FJ fails on that front. Any suggestions?

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