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  • Working with extra fields in an Inline form - save_model, save_formset, can't make sense of the diff

    - by magicrebirth
    Suppose I am in the usual situation where there're extra fields in the many2many relationship: class Person(models.Model): name = models.CharField(max_length=128) class Group(models.Model): name = models.CharField(max_length=128) members = models.ManyToManyField(Person, through='Membership') class Membership(models.Model): person = models.ForeignKey(Person) group = models.ForeignKey(Group) date_joined = models.DateField() invite_reason = models.CharField(max_length=64) # other models which are unrelated to the ones above.. class Trip(models.Model): placeVisited = models.ForeignKey(Place) visitor = models.ForeignKey(Person) pleasuretrip = models.Boolean() class Place(models.Model): name = models.CharField(max_length=128) I want to add some extra fields in the Membership form that gets displayed through the Inline. These fields basically are a shortcut to the instantiation of another model (Trip). Trip can have its own admin views, but these shortcuts are needed because when my project partners are entering 'Membership' data in the system they happen to have also the 'Trip' information handy (and also because some of the info in Membership can just be copied over to Trip etc. etc.). So all I want to have is two extra fields in the Membership Inline - placeVisited and pleasuretrip - which together with the Person instance will let me instantiate the Trip model in the background... I found out I can easily add extra fields to the inline view by defining my own form. But once the data have been entered, how and when to reference to them in order to perform the save operations I need to do? class MyForm(forms.ModelForm): place = forms.ModelChoiceField(required=False, queryset=Place.objects.all(), label="place",) pleasuretrip = forms.BooleanField(required=False, label="...") class MembershipInline(admin.TabularInline): model = Membership form = MyForm def save_model(self, request, obj, form, change): place = form.place pleasuretrip = form.pleasuretrip person = form.person .... # now I can create Trip instances with those data .... obj.save() class GroupAdmin(admin.ModelAdmin): model = Group .... inlines = (MembershipInline,) This doesn't seem to work... I'm also a bit puzzled by the save_formset method... maybe is that the one I should be using? Many thanks in advance for the help!!!!

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  • constructor function's object literal returns toString() method but no other method

    - by JohnMerlino
    I'm very confused with javascript methods defined in objects and the "this" keyword. In the below example, the toString() method is invoked when Mammal object instantiated: function Mammal(name){ this.name=name; this.toString = function(){ return '[Mammal "'+this.name+'"]'; } } var someAnimal = new Mammal('Mr. Biggles'); alert('someAnimal is '+someAnimal); Despite the fact that the toString() method is not invoked on the object someAnimal like this: alert('someAnimal is '+someAnimal.toString()); It still returns 'someAnimal is [Mammal "Mr. Biggles"]' . That doesn't make sense to me because the toString() function is not being called anywhere. Then to add even more confusion, if I change the toString() method to a method I make up such as random(): function Mammal(name){ this.name=name; this.random = function(){ return Math.floor(Math.random() * 15); } } var someAnimal = new Mammal('Mr. Biggles'); alert(someAnimal); It completely ignores the random method (despite the fact that it is defined the same way was the toString() method was) and returns: [object object] Another issue I'm having trouble understanding with inheritance is the value of "this". For example, in the below example function person(w,h){ width.width = w; width.height = h; } function man(w,h,s) { person.call(this, w, h); this.sex = s; } "this" keyword is being send to the person object clearly. However, does "this" refer to the subclass (man) or the super class (person) when the person object receives it? Thanks for clearing up any of the confusion I have with inheritance and object literals in javascript.

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  • Stored procedure woes ... inserting binary ...

    - by Wardy
    Ok so I have this storedproc in my SQL 2008 database (works in 2005 too / used to) ... CREATE PROCEDURE [dbo].[SetBinaryContent] @Ref nvarchar(50), @Content varbinary(MAX), @ObjectID uniqueidentifier AS BEGIN DELETE ObjectContent WHERE ObjectId = @ObjectID AND Ref = @Ref IF DATALENGTH(@Content) > 5 BEGIN INSERT INTO ObjectContent (Ref,BinaryContent,ObjectId) VALUES (@Ref,@Content,@ObjectId) END UPDATE Objects SET [Status] = 1 WHERE ID = @ObjectID END Relatively simple, I take a byte array in C# and chuck it in @Content i then give it a guid and string for the other params and off we go. ... Great, it used to work ... but it don't anymore ... so erm ... What's wrong with this stored proc? I've stepped through my C# code thinking I screwed up somehow in that but it definately adds the params and gives them the correct values so what would cause the server to just stop executing this storedproc correctly? When called this proc executes but nothing changes in the db ... no new records are added to the ObjectContent table. Weird huh ...

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  • How do I create a dynamic data transfer object dynamically from ADO.net model

    - by Richard
    I have a pretty simple database with 5 tables, PK's and relationships setup, etc. I also have an ASP.net MVC3 project I'm using to create simple web services to feed JSON/XML to a mobile app using post/get. To access my data I'm using an ADO.net entity model class to handle generation of the entities, etc. Due to issues with serialization/circular references created by the auto-generated relations from ADO.net entity model, I've been forced to create "Data transfer objects" to strip out the relations and data that doesn't need to be transferred. Question 1: is there an easier way to create DTOs using the entity framework itself? IE, specify only the entity properties I want to convert to Jsonresults? I don't wish to use any 3rd party frameworks if I can help it. Question 2: A side question for Entity Framework, say I create an ADO.net entity model in one project within a solution. Because that model relies on the connection to the database specified in project A, can project B somehow use that model with a similar connection? Both projects are in the same solution. Thanks!

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  • Generating SQL change scripts in SSMS 2008

    - by Munish Goyal
    I have gone through many related SO threads and got some basic info. Already generated DB diagram. After that i am unable to find a button/option to generate SQL scripts (create) for all the tables in diagram. "Generate script" button is disabled, even on clicking the table in diagram. However i enabled the auto-generate option in tools-designer. But what to do with previous diagrams. I just want an easy way to auto-generate such scripts (create/alter) and would be gud if i get auto-generated stored procs for insert/selects/update etc. EDIT: I could do generate scripts for DB objects. Now: 1. How to import DB diagram from another DB. 2. How to generate (and manage their change integrated with VS source control) routine stored-procs like insert, update and select. Ok let me ask another way, can experts guide on the usual flow of creating/altering tables (across releases), creating stored-procs (are stored-procs the best way to go ?) and their change-management using SSMS design tools and minimal effort ?

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  • Django formset doesn't validate

    - by tsoporan
    Hello, I am trying to save a formset but it seems to be bypassing is_valid() even though there are required fields. To test this I have a simple form: class AlbumForm(forms.Form): name = forms.CharField(required=True) The view: @login_required def add_album(request, artist): artist = Artist.objects.get(slug__iexact=artist) AlbumFormSet = formset_factory(AlbumForm) if request.method == 'POST': formset = AlbumFormSet(request.POST, request.FILES) if formset.is_valid(): return HttpResponse('worked') else: formset = AlbumFormSet() return render_to_response('submissions/addalbum.html', { 'artist': artist, 'formset': formset, }, context_instance=RequestContext(request)) And the template: <form action="" method="post" enctype="multipart/form-data">{% csrf_token %} {{ formset.management_form }} {% for form in formset.forms %} <ul class="addalbumlist"> {% for field in form %} <li> {{ field.label_tag }} {{ field }} {{ field.errors }} </li> {% endfor %} </ul> {% endfor %} <div class="inpwrap"> <input type="button" value="add another"> <input type="submit" value="add"> </div> </form> What ends up happening is I hit "add" without entering a name then HttpResponse('worked') get's called seemingly assuming it's a valid form. I might be missing something here, but I can't see what's wrong. What I want to happen is, just like any other form if the field is required to spit out an error if its not filled in. Any ideas?

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  • should the builder reset its build environment after delivering the product

    - by Sudhi
    I am implementing a builder where in the deliverable is retrieved by calling Builder::getProduct() . The director asks various parts to build Builder::buildPartA() , Builder::buildPartB() etc. in order to completely build the product. My question is, once the product is delivered by the Builder by calling Builder::getProduct(), should it reset its environment (Builder::partA = NULL;, Builder::partB = NULL;) so that it is ready to build another product? (with same or different configuration?) I ask this as I am using PHP wherein the objects are by default passed by reference (nope, I don't want to clone them, as one of their field is a Resource) . However, even if you think from a language agnostic point of view, should the Builder reset its build environment ? If your answer is 'it depends on the case' what use cases would justify reseting the environment (and other way round) ? For the sake of providing code sample here's my Builder::gerProcessor() which shows what I mean by reseting the environment /** * @see IBuilder::getProessor() */ public function getProcessor() { if($this->_processor == NULL) { throw new LogicException('Processor not yet built!'); } else { $retval = $this->_processor; $this->_product = NULL, $this->_processor = NULL; } return $retval; }

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  • How do JVM's implicit memory barriers behave when chaining constructors

    - by Joonas Pulakka
    Referring to my earlier question on incompletely constructed objects, I have a second question. As Jon Skeet pointed out, there's an implicit memory barrier in the end of a constructor that makes sure that final fields are visible to all threads. But what if a constructor calls another constructor; is there such a memory barrier in the end of each of them, or only in one being called from outside? That is, when the "wrong" solution is: public class ThisEscape { public ThisEscape(EventSource source) { source.registerListener( new EventListener() { public void onEvent(Event e) { doSomething(e); } }); } } And the correct one would be a factory method version: public class SafeListener { private final EventListener listener; private SafeListener() { listener = new EventListener() { public void onEvent(Event e) { doSomething(e); } } } public static SafeListener newInstance(EventSource source) { SafeListener safe = new SafeListener(); source.registerListener(safe.listener); return safe; } } Would the following work too, or not? public class MyListener { private final EventListener Listener; private MyListener() { listener = new EventListener() { public void onEvent(Event e) { doSomething(e); } } } public MyListener(EventSource source) { this(); source.register(listener); } }

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  • What is the most efficient/elegant way to parse a flat table into a tree?

    - by Tomalak
    Assume you have a flat table that stores an ordered tree hierarchy: Id Name ParentId Order 1 'Node 1' 0 10 2 'Node 1.1' 1 10 3 'Node 2' 0 20 4 'Node 1.1.1' 2 10 5 'Node 2.1' 3 10 6 'Node 1.2' 1 20 What minimalistic approach would you use to output that to HTML (or text, for that matter) as a correctly ordered, correctly intended tree? Assume further you only have basic data structures (arrays and hashmaps), no fancy objects with parent/children references, no ORM, no framework, just your two hands. The table is represented as a result set, which can be accessed randomly. Pseudo code or plain English is okay, this is purely a conceptional question. Bonus question: Is there a fundamentally better way to store a tree structure like this in a RDBMS? EDITS AND ADDITIONS To answer one commenter's (Mark Bessey's) question: A root node is not necessary, because it is never going to be displayed anyway. ParentId = 0 is the convention to express "these are top level". The Order column defines how nodes with the same parent are going to be sorted. The "result set" I spoke of can be pictured as an array of hashmaps (to stay in that terminology). For my example was meant to be already there. Some answers go the extra mile and construct it first, but thats okay. The tree can be arbitrarily deep. Each node can have N children. I did not exactly have a "millions of entries" tree in mind, though. Don't mistake my choice of node naming ('Node 1.1.1') for something to rely on. The nodes could equally well be called 'Frank' or 'Bob', no naming structure is implied, this was merely to make it readable. I have posted my own solution so you guys can pull it to pieces.

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  • Django db encoding

    - by realshadow
    Hey, I have a little problem with encoding. The data in db is ok, when I select the data in php its ok. Problem comes when I get the data and try to print it in the template, I get - Å port instead of Šport, etc. Everything is set to utf-8 - in settings.py, meta tags in template, db table and I even have unicode method specified for the model, but nothing seems to work. I am getting pretty hopeless here... Here is some code: class Category_info(models.Model): objtree_label_id = models.AutoField(primary_key = True) node_id = models.IntegerField(unique = True) language_id = models.IntegerField() label = models.CharField(max_length = 255) type_id = models.IntegerField() class Meta: db_table = 'objtree_labels' def __unicode__(self): return self.label I have even tried with return u"%s" % self.label. Here is the view: def categories_list(request): categories_list = Category.objects.filter(parent_id = 1, status = 1) paginator = Paginator(categories_list, 10) try: page = int(request.GET.get('page', 1)) except ValueError: page = 1 try: categories = paginator.page(page) except (EmptyPage, InvalidPage): categories = paginator.page(paginator.num_pages) return render_to_response('categories_list.html', {'categories': categories}) Maybe I am just blind and/or stupid, but it just doesnt work. So any help is appreciated, thanks in advance. Regards

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  • Simulating mouse clicks on Mac OS X does not work for some applications.

    - by Thomi
    I'm writing an application for Mac OS X 10.6 and later in C++. One part of the application needs to simulate mouse movement and mouse clicks. I do this currently by posting CGEvent objects using CGEventPost(kCGHIDEventTap, event);. This works, for the most part - I can simulate mouse movement and clicks just fine, but it seems to fail in some areas. For example: In Mozilla Firefox and Safari, I can click on all the menus, but cannot click on a link within a website. When I try, the link is highlighted, but the browser never follows the link. However, I can right-click on a link, select "open link in new tab", and everything works as expected. Solved - creating the mouse event using CGEventCreateMouseEvent(...) makes the event work within web browser. I can click on the "Dashboard" icon to brink up the dashboard, but I cannot click on the "i" button on any of the dashboard widgets. Similarly, clicking on any of the search results from the spotlight search widget doesn't work either. This inconsistency is along application boundaries. What might be the cause?

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  • User preferences using SQL and JavaScript

    - by Shyam
    Hi, I am using Server Side JavaScript - yes, I am actually using Server Side JavaScript. To complexify things even more, I use Oracle as a backend database (10g). With some crazy XSLT and mutant-like HTML generation, I can build really fancy web forms - yes, I am aware of Rails and other likewise frameworks and I choose the path of horror instead. I have no JQuery or other fancy framework at my disposal, just plain ol' JavaScript that should be supported by the underlying engine called Mozilla Rhino. Yes, it is insane and I love it. So, I have a bunch of tables at my disposal and some of them are filled with associative keys that link to values. As I am a people pleaser, I want to add some nifty user-preference driven solutions. My users have all an unique user_id and this user_id is available during the entire session. My initial idea is to have a user preference table, where I have "three" columns: user_id, feature and pref_string. Using a delimiter, such as : or - (haven't thought about a suitable one yet), I could like store a bunch of preferences as a list and store its elements inside an array using the .split-method (similar like the PHP-explode function). The feature column could be like the table name or some identifier for the "feature" i want to link preferences too. I hate hardcoding objects, especially as I want to be able to back these up and reuse this functionality application-wide. Of course I would love better ideas, just keep in mind I cannot just add a library that easily. These preferences could be like "joined" to the table, so I can query it and use its values. I hope it doesn't sounds too complex, because well.. its basically something really simple I need. Thanks!

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  • How should I use .ico files in a Winforms Application ?

    - by Brann
    I'm developing a WinForms c# 3.0 application. Our designer created quite a lot of .ico files containing all the needed art. The choice of .ico was made because quite often, the same image is needed in several places in different dimensions. Now, it seems .ico files are really annoying to use in visual studio. The only way to use those images seems to be through images list (which aren't supported by all controls). Compared to other resources, you can't write this : foo.Image = global::RFQHUB.RFQHUBClient.Properties.Resources.foo; // Cannot implicitly convert type 'System.Drawing.Icon' to 'System.Drawing.Image' Here are the options I'm considering : create ImageLists of all possible sizes referencing all my icons in my main window. Link these ImageLists from other windows and find a way to export Image objects from the ImageList when I can't use it directly ; since ImageList contains a Draw() method, this should probably be possible. convert all the x.ico I've got in several x16.gif ...x48.gif, and use those through resources. I'd be interested to know if some people have been successfully using .ico resources in a Winform application. In so, how did you set up things ?

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  • MVVM pattern: ViewModel updates after Model server roundtrip

    - by Pavel Savara
    I have stateless services and anemic domain objects on server side. Model between server and client is POCO DTO. The client should become MVVM. The model could be graph of about 100 instances of 20 different classes. The client editor contains diverse tab-pages all of them live-connected to model/viewmodel. My problem is how to propagate changes after server round-trip nice way. It's quite easy to propagate changes from ViewModel to DTO. For way back it would be possible to throw away old DTO and replace it whole with new one, but it will cause lot of redrawing for lists/DataTemplates. I could gather the server side changes and transmit them to client side. But the names of fields changed would be domain/DTO specific, not ViewModel specific. And the mapping seems nontrivial to me. If I should do it imperative way after round-trip, it would break SOC/modularity of viewModels. I'm thinking about some kind of mapping rule engine, something like automappper or emit mapper. But it solves just very plain use-cases. I don't see how it would map/propagate/convert adding items to list or removal. How to identify instances in collections so it could merge values to existing instances. As well it should propagate validation/error info. Maybe I should implement INotifyPropertyChanged on DTO and try to replay server side events on it ? And then bind ViewModel to it ? Would binding solve the problems with collection merges nice way ? Is EventAgregator from PRISM useful for that ? Is there any event record-replay component ? Is there better client side pattern for architecture with server side logic ?

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  • What are the options for overriding Django's cascading delete behaviour?

    - by Tom
    Django models generally handle the ON DELETE CASCADE behaviour quite adequately (in a way that works on databases that don't support it natively.) However, I'm struggling to discover what is the best way to override this behaviour where it is not appropriate, in the following scenarios for example: ON DELETE RESTRICT (i.e. prevent deleting an object if it has child records) ON DELETE SET NULL (i.e. don't delete a child record, but set it's parent key to NULL instead to break the relationship) Update other related data when a record is deleted (e.g. deleting an uploaded image file) The following are the potential ways to achieve these that I am aware of: Override the model's delete() method. While this sort of works, it is sidestepped when the records are deleted via a QuerySet. Also, every model's delete() must be overridden to make sure Django's code is never called and super() can't be called as it may use a QuerySet to delete child objects. Use signals. This seems to be ideal as they are called when directly deleting the model or deleting via a QuerySet. However, there is no possibility to prevent a child object from being deleted so it is not usable to implement ON CASCADE RESTRICT or SET NULL. Use a database engine that handles this properly (what does Django do in this case?) Wait until Django supports it (and live with bugs until then...) It seems like the first option is the only viable one, but it's ugly, throws the baby out with the bath water, and risks missing something when a new model/relation is added. Am I missing something? Any recommendations?

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  • item-not-found(404) when trying to get a node using Smackx pubsub

    - by DustMason
    I'm trying to use the latest Smackx trunk to get and then subscribe to a pubsub node. However, openfire just sends me a back an error: item not found (404). I am instantiating the java objects from ColdFusion, so my code snippets might look funny but maybe someone will be able to tell me what I've forgotten. Here's how I create the node: ftype = createObject("java", "org.jivesoftware.smackx.pubsub.FormType"); cform = createObject("java", "org.jivesoftware.smackx.pubsub.ConfigureForm").init(ftype.submit); cform.setPersistentItems(true); cform.setDeliverPayloads(true); caccess = createObject("java", "org.jivesoftware.smackx.pubsub.AccessModel"); cform.setAccessModel(caccess.open); cpublish = createObject("java", "org.jivesoftware.smackx.pubsub.PublishModel"); cform.setPublishModel(cpublish.open); cform.setMaxItems(99); manager = createObject("java", "org.jivesoftware.smackx.pubsub.PubSubManager").init(XMPPConnection); myNode = manager.createNode("subber", cform); And here's how I am trying to get to it (in a different section of code): manager = createObject("java", "org.jivesoftware.smackx.pubsub.PubSubManager").init(XMPPConnection); myNode = manager.getNode("subber"); Immediately upon creating the node I seem to be able to publish to it like so: payload = createObject("java", "org.jivesoftware.smackx.pubsub.SimplePayload").init("book","pubsub:test:book","<book xmlns='pubsub:test:book'><title>Lord of the Rings</title></book>"); item = createObject("java", "org.jivesoftware.smackx.pubsub.Item").init(payload); myNode.publish(item); However, it is the getNode() call that is causing my code to error. I have verified that the nodes are being created by checking the DB used by my openfire server. I can see them in there, properly attributed as leaf nodes, etc. Any advice? Anyone else out there doing anything with XMPP and ColdFusion? I have had great success sending and receiving messages with CF and Smack just haven't had the pubsub working yet :) Thanks!

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  • How to include external classes in a GAE deployment?

    - by kodra
    I am using the Google plug-in for Eclipse and have the following problem: The project consists of a GWT based GUI talking to a server running on GAE and using JPA. Additionally there is a project to migrate the legacy data to the new datastore. Since these both project use common data model, I have extracted a set of interfaces and enums into a separate project and set the other two projects dependencies on it. The Java App project seems to work, but the GWT/GAE only works if I manually copy the classes into the WEB-INF/classes directory. Obviously this is only working when using the housted mode. Anybody knows how to configure such a multi project setup in Eclipse? Also, I am not sure if the multi project layout is the best solution. The set of common model objects is used in all 3 areas: user client (GWT project compiling standard folders client and shared) server side (providing services for GWT-RPC, uploading and different feeds) migration application (posting the legacy data to the upload servlet) What are the architectural options to keep the amount of duplicated classes on minimum?

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  • Elegant way of parsing Data files for Simulation

    - by sc_ray
    I am working on this project where I need to read in a lot of data from .dat files and use the data to perform simulations. The data in my .dat file looks as follows: DeviceID InteractingDeviceID InteractionStartTime InteractionEndTime 1 2 1101 1105 1,2 1101 and 1105 are tab delimited and it means Device 1 interacted with Device 2 at 1101 ms and ended the interaction at 1105ms. I have a trace data sets that compile thousands of such interactions and my job is to analyze these interactions. The first step is to parse the file. The language of choice is C++. The approach I was thinking of taking was to read the file, for every line that's read create a Device Object. This Device object will contain the property DeviceId and an array/vector of structs, that will contain a list of all the devices the given DeviceId interacted with over the course of the simulation.The struct will contain the Interacting Device Id, Interaction Start Time and Interaction End Time. I have a two fold question here: Is my approach correct? If I am on the right track, how do I rapidly parse these tab delimited data files and create Device objects without excessive memory overhead using C++? A push in the right direction will be much appreciated. Thanks

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  • C# reflection instantiation

    - by NickLarsen
    I am currently trying to create a generic instance factory for which takes an interface as the generic parameter (enforced in the constructor) and then lets you get instantiated objects which implement that interface from all types in all loaded assemblies. The current implementation is as follows:     public class InstantiationFactory     {         protected Type Type { get; set; }         public InstantiationFactory()         {             this.Type = typeof(T);             if (!this.Type.IsInterface)             {                 // is there a more descriptive exception to throw?                 throw new ArgumentException(/* Crafty message */);             }         }         public IEnumerable GetLoadedTypes()         {             // this line of code found in other stack overflow questions             var types = AppDomain.CurrentDomain.GetAssemblies()                 .SelectMany(a = a.GetTypes())                 .Where(/* lambda to identify instantiable types which implement this interface */);             return types;         }         public IEnumerable GetImplementations(IEnumerable types)         {             var implementations = types.Where(/* lambda to identify instantiable types which implement this interface */                 .Select(x = CreateInstance(x));             return implementations;         }         public IEnumerable GetLoadedImplementations()         {             var loadedTypes = GetLoadedTypes();             var implementations = GetImplementations(loadedTypes);             return implementations;         }         private T CreateInstance(Type type)         {             T instance = default(T);             var constructor = type.GetConstructor(Type.EmptyTypes);             if (/* valid to instantiate test */)             {                 object constructed = constructor.Invoke(null);                 instance = (T)constructed;             }             return instance;         }     } It seems useful to me to have my CreateInstance(Type) function implemented as an extension method so I can reuse it later and simplify the code of my factory, but I can't figure out how to return a strongly typed value from that extension method. I realize I could just return an object:     public static class TypeExtensions     {         public object CreateInstance(this Type type)         {             var constructor = type.GetConstructor(Type.EmptyTypes);             return /* valid to instantiate test */ ? constructor.Invoke(null) : null;         }     } Is it possible to have an extension method create a signature per instance of the type it extends? My perfect code would be this, which avoids having to cast the result of the call to CreateInstance():     Type type = typeof(MyParameterlessConstructorImplementingType);     MyParameterlessConstructorImplementingType usable = type.CreateInstance();

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  • In Java it seems Public constructors are always a bad coding practice

    - by Adam Gent
    This maybe a controversial question and may not be suited for this forum (so I will not be insulted if you choose to close this question). It seems given the current capabilities of Java there is no reason to make constructors public ... ever. Friendly, private, protected are OK but public no. It seems that its almost always a better idea to provide a public static method for creating objects. Every Java Bean serialization technology (JAXB, Jackson, Spring etc...) can call a protected or private no-arg constructor. My questions are: I have never seen this practice decreed or written down anywhere? Maybe Bloch mentions it but I don't own is book. Is there a use case other than perhaps not being super DRY that I missed? EDIT: I explain why static methods are better. .1. For one you get better type inference. For example See Guava's http://code.google.com/p/guava-libraries/wiki/CollectionUtilitiesExplained .2. As a designer of the class you can later change what is returned with a static method. .3. Dealing with constructor inheritance is painful especially if you have to pre-calculate something.

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  • Laggy interface with NSSearchField hooked up to an NSArrayController via bindings

    - by Simone Manganelli
    So I've got an NSSearchField hooked up directly to an NSArrayController via bindings, attached to the filterPredicate, so that without any code, the user can just type in the NSSearchField and filter the list of objects in the NSArrayController presented to him in the interface (an NSCollectionView, to be specific). The NSSearchField is hooked up to provide live searching, so that the NSCollectionView is filtered instantly as the user types, not after waiting for a short period for the user to stop typing. However, the problem is that this makes the interface really laggy. Typing is delayed significantly, by 0.5-1 seconds, and it seems like the NSCollectionView is trying to animate each and every rearrangement of items for each portion of the search string that the user enters. What I'd like is for the searching to be live, but the typing in the search field to be fluid, and the results to filter as fast as possible. Is there a way to do this via bindings, or will I need to put in some custom code that triggers the filterPredicate on a separate thread? (Note that I've got a custom sorting algorithm set up on the NSArrayController, and removing it seems to help a bit with the laggyness, but not completely.)

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  • django hidden field error

    - by dana
    hi, there, i'm building a message system for a virtual community, but i can't take the userprofile id i have in views.py def save_message(request): if request.method == 'POST': form = MessageForm(request.POST) if form.is_valid(): new_obj = form.save(commit=False) new_obj.sender = request.user u = UserProfile.objects.get(request.POST['userprofile_id']) new_obj.owner = u new_obj.save() return HttpResponseRedirect('.') else: form = MessageForm() return render_to_response('messages/messages.html', { 'form': form, }, context_instance=RequestContext(request)) and the template: {% block primary %} <form action="." method="post"> {{ form.as_p }} <p><input type="hidden" value="{{ userprofile.id }}" name = "owner" /></p> <p><input type="submit" value="Send Message!" /></p> </form> {% endblock %} forms.py: class MessageForm(ModelForm): class Meta: model = Messages fields = ['message'] models.py: class Messages(models.Model): message = models.CharField(max_length = 300) read = models.BooleanField(default=False) owner = models.ForeignKey(UserProfile) sender = models.ForeignKey(User) I don't figure out why i get this error,since i'm just trying to get the profileId of a user, using a hiddeen field. the error is: Key 'UserProfile_id' not found in <QueryDict: {u'owner': [u''], u'message': [u'fdghjkl']}> and i'm getting it after i fill out the message text field. Thanks!

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  • How do I write a J2EE/EJB Singleton?

    - by Bears will eat you
    A day ago my application was one EAR, containing one WAR, one EJB JAR, and a couple of utility JAR files. I had a POJO singleton class in one of those utility files, it worked, and all was well with the world: EAR |--- WAR |--- EJB JAR |--- Util 1 JAR |--- Util 2 JAR |--- etc. Then I created a second WAR and found out (the hard way) that each WAR has its own ClassLoader, so each WAR sees a different singleton, and things break down from there. This is not so good. EAR |--- WAR 1 |--- WAR 2 |--- EJB JAR |--- Util 1 JAR |--- Util 2 JAR |--- etc. So, I'm looking for a way to create a Java singleton object that will work across WARs (across ClassLoaders?). The @Singleton EJB annotation seemed pretty promising until I found that JBoss 5.1 doesn't seem to support that annotation (which was added as part of EJB 3.1). Did I miss something - can I use @Singleton with JBoss 5.1? Upgrading to JBoss AS 6 is not an option right now. Alternately, I'd be just as happy to not have to use EJB to implement my singleton. What else can I do to solve this problem? Basically, I need a semi-application-wide* hook into a whole bunch of other objects, like various cached data, and app config info. As a last resort, I've already considered merging my two WARs into one, but that would be pretty hellish. *Meaning: available basically anywhere above a certain layer; for now, mostly in my WARs - the View and Controller (in a loose sense).

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  • Recommendations of a high volume log event viewer in a Java enviroment

    - by Thorbjørn Ravn Andersen
    I am in a situation where I would like to accept a LOT of log events controlled by me - notably the logging agent I am preparing for slf4j - and then analyze them interactively. I am not as such interested in a facility that presents formatted log files, but one that can accept log events as objects and allow me to sort and display on e.g. threads and timelines etc. Chainsaw could maybe be an option but is currently not compatible with logback which I use for technical reasons. Is there any project with stand alone viewers or embedded in an IDE which would be suitable for this kind of log handling. I am aware that I am approaching what might be suitable for a profiler, so if there is a profiler projekt suitable for this kind of data acquisition and display where I can feed the event pipe, I would like to hear about it). Thanks for all feedback Update 2009-03-19: I have found that there is not a log viewer which allows me to see what I would like (a visual display of events with coordinates determined by day and time, etc), so I have decided to create a very terse XML format derived from the log4j XMLLayout adapted to be as readable as possible while still being valid XML-snippets, and then use the Microsoft LogParser to extract the information I need for postprocessing in other tools.

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  • Retrieve a TextBox element dinamically created and Focus it

    - by user335444
    Hi, I have a collection (VariableValueCollection) of custom type VariableValueViewModel objects binded with a ListView. WPF Follow: <ListView ItemsSource="{Binding VariableValueCollection}" Name="itemList"> <ListView.Resources> <DataTemplate DataType="{x:Type vm:VariableValueViewModel}"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="180"></ColumnDefinition> </Grid.ColumnDefinitions> <TextBox TabIndex="{Binding Path=Index, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}" Grid.Column="0" Name="tbValue" Focusable="True" LostFocus="tbValue_LostFocus" GotFocus="tbValue_GotFocus" KeyDown="tbValue_KeyDown"> <TextBox.Text> <Binding Path="Value" UpdateSourceTrigger="PropertyChanged" Mode="TwoWay"> <Binding.ValidationRules> <ExceptionValidationRule></ExceptionValidationRule> </Binding.ValidationRules> </Binding> </TextBox.Text> </TextBox> </Grid> </DataTemplate> </ListView.Resources> </ListView> My Goal is to add a new row when I press "enter" on last row, and Focus the new row. To do that, I check that row is the last row and add a new row in that case. But I don't know how to focus the new TextBox... Here the KeyPressed method: private void tbValue_KeyDown(object sender, KeyEventArgs e) { if (e.Key == System.Windows.Input.Key.Enter) { DependencyObject obj = itemList.ContainerFromElement((sender as TextBox)); int index = itemList.ItemContainerGenerator.IndexFromContainer(obj); if( index == (VariableValueCollection.Count - 1) ) { // Create a VariableValueViewModel object and add to collection. In binding, that create a new list item with a new TextBox ViewModel.AddNewRow(); // How to set cursor and focus last row created? } } } Thank's in advance...

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