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  • Why Finalize method not allowed to override

    - by somaraj
    I am new to .net ..and i am confused with the destructor mechanism in C# ..please clarify In C# destructors are converted to finalize method by CLR. If we try to override it (not using destructor ) , will get an error Error 2 Do not override object.Finalize. Instead, provide a destructor. But it seems that the Object calss implementation in mscorlib.dll has finalize defined as protected override void Finalize(){} , then why cant we override it , that what virtual function for . Why is the design like that , is it to be consistent with c++ destructor concept. Also when we go to the definition of the object class , there is no mention of the finalize method , then how does the hmscorlib.dll definition shows the finalize funtion . Does it mean that the default destructor is converted to finalize method. public class Object { public Object(); public virtual bool Equals(object obj); public static bool Equals(object objA, object objB); public virtual int GetHashCode(); public Type GetType(); protected object MemberwiseClone(); public static bool ReferenceEquals(object objA, object objB); public virtual string ToString(); }

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  • CharField values disappearing after save (readonly field)

    - by jamida
    I'm implementing simple "grade book" application where the teacher would be able to update the grades w/o being allowed to change the students' names (at least not on the update grade page). To do this I'm using one of the read-only tricks, the simplest one. The problem is that after the SUBMIT the view is re-displayed with 'blank' values for the students. I'd like the students' names to re-appear. Below is the simplest example that exhibits this problem. (This is poor DB design, I know, I've extracted just the relevant parts of the code to showcase the problem. In the real example, student is in its own table but the problem still exists there.) models.py class Grade1(models.Model): student = models.CharField(max_length=50, unique=True) finalGrade = models.CharField(max_length=3) class Grade1OForm(ModelForm): student = forms.CharField(max_length=50, required=False) def __init__(self, *args, **kwargs): super(Grade1OForm,self).__init__(*args, **kwargs) instance = getattr(self, 'instance', None) if instance and instance.id: self.fields['student'].widget.attrs['readonly'] = True self.fields['student'].widget.attrs['disabled'] = 'disabled' def clean_student(self): instance = getattr(self,'instance',None) if instance: return instance.student else: return self.cleaned_data.get('student',None) class Meta: model=Grade1 views.py from django.forms.models import modelformset_factory def modifyAllGrades1(request): gradeFormSetFactory = modelformset_factory(Grade1, form=Grade1OForm, extra=0) studentQueryset = Grade1.objects.all() if request.method=='POST': myGradeFormSet = gradeFormSetFactory(request.POST, queryset=studentQueryset) if myGradeFormSet.is_valid(): myGradeFormSet.save() info = "successfully modified" else: myGradeFormSet = gradeFormSetFactory(queryset=studentQueryset) return render_to_response('grades/modifyAllGrades.html',locals()) template <p>{{ info }}</p> <form method="POST" action=""> <table> {{ myGradeFormSet.management_form }} {% for myform in myGradeFormSet.forms %} {# myform.as_table #} <tr> {% for field in myform %} <td> {{ field }} {{ field.errors }} </td> {% endfor %} </tr> {% endfor %} </table> <input type="submit" value="Submit"> </form>

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  • Help with mysql sum and group query and managing jquery graph results.

    - by Scarface
    Hey guys, I have a system I am trying to design that will retrieve information from a database, so that it can be plotted in a jquery graph. I need to retrieve the information and somehow put it in the necessary format (for example two coordinates var d = [[1269417600000, 10],[1269504000000, 15]];). My table that I am selecting from is a table that stores user votes with fields: points_id (1=vote up ,2=vote down), user_id, timestamp, and topic_id. What I need to do is select all the votes and somehow group them into respective days and then sum the difference between 1 votes and 2 votes for each day. I then need to somehow display the data in the appropriate plotting format shown earlier. For example April 1, 4 votes. The data needs to be separated by commas, except the last plot entry, so I am not sure how to approach that. I showed an example below of the kind of thing I need but it is not correct, echo "var d=["; $query=mysql_query("SELECT *, SUM(IF(points_id = \"1\", 1,0))-SUM(IF([points_id = \"2\", 1,0)) AS 'total' FROM points LEFT JOIN topic on topic.topic_id=points.topic_id WHERE topic.creator='$user' GROUP by timestamp HAVING certain time interval"); while ($row=mysql_fetch_assoc($query)){ $timestamp=$row['timestamp']; $votes=$row['total']; echo "[$timestamp,$vote],"; } echo "];";

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  • Asp net aspx page and webcontrol issue

    - by Josemalive
    Hello, I have a class that inherits from Page, called APage. public abstract class APage: Page { protected Repeater ExampleRepeater; .... protected override void OnLoad(EventArgs e) { if (null != ExampleRepeater) { ExampleRepeater.DataSource = GetData(); ExampleRepeater.DataBind(); } base.OnLoad(e); } } For other hand i have an aspx page called Default that inherits from this APage: public partial class Default : APage { } on the design part of this Default page, i have a repeater: <asp:Repeater ID="ExampleRepeater" runat="server"> <ItemTemplate> <%# DataBinder.Eval(Container.DataItem, "Name") %><br/> </ItemTemplate> </asp:Repeater> This repeater is datasourced at the base APage load event, but at this level this web control is null. Do you have any idea why the control is null in the base page? Thanks in advance. Best Regards. Jose.

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  • Custom UIButton for Iphone.

    - by Amal
    I have an view in my App which has a number of buttons based on the number of items returned by the server. So if the server returns say 10 items, there should be 10 buttons and clicking on each button should call a different person. For the above purpose I created a custom button class deriving from UIButton. @implementation HopitalButton @synthesize index; @synthesize button_type; - (id)initWithFrame:(CGRect)frame { if (self = [super initWithFrame:frame]) { UIImage* img = [UIImage imageNamed:@"dr_btn.png"]; [img stretchableImageWithLeftCapWidth:10 topCapHeight:10]; [self setBackgroundImage:img forState:UIControlStateNormal]; [self setTitleColor:[UIColor colorWithRed:0.698 green:0.118 blue:0.376 alpha:1] forState:UIControlStateNormal] ; [self setFont:[UIFont fontWithName:@"Helvetica Bold" size:13]]; self.titleLabel.textColor = [UIColor colorWithRed:178 green:48 blue:95 alpha:1]; self.adjustsImageWhenHighlighted = YES; } return self; } - (void)dealloc { [super dealloc]; } @end Now the problem with the above code is that it does not create buttons that look similar to the buttons created by default in Interface builder. The borders are missing. And I create buttons of the above type by the following code: HopitalButton* hb = [[HopitalButton alloc] init]; hb.button_type = @"call"; hb.frame = CGRectMake(50, 50 + i * 67, 220, 40); [self.scroll_view addSubview:hb]; [hb setTitle:[[[self.office_full_list objectAtIndex:i] objectForKey:@"Staff" ]objectForKey:@"FullName"] forState:UIControlStateNormal]; hb.index = [NSNumber numberWithInt:[self.button_items count]]; [self.button_items insertObject:hb atIndex:[self.button_items count]]; [hb addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside]; I am not finding a way to set the button type for this custom button. Is there a way i can do it ? Or is there a better way to design the code.

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  • Starting a new business with former colleagues, advice needed

    - by Sparafusile
    I was recently contacted by a former boss of mine who is thinking of starting a new business. The business will be online only it will by my job to design, build, and maintain the software going into it. I will also have to maintain the server it's running on, being the only technical person on the team. I will be one of four members of the business, the other three being the actual business know-hows and salesmen. The other three are shouldering the cost of getting the business going (incorporation, attorney fees, etc) and we will be splitting the cost of the server. I have no business knowledge at all, and don't want any part of it, I am only interested in the technical aspects. Now that we are finalizing our plans, determining roles, and getting ready to start actual work, we have come to the point where we have to determine what percentage stake each of us has. Since I have never done anything like this before, or met anyone that has, I don't know what I should expect. Can anyone give me some pointers on what to ask for in this deal?

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  • Interactive Web Collaboration Platform

    - by user1477586
    I am currently unsatisfied with most, if not all, web-based collaboration tools I've ever used. Examples of what I'm considering a "web-based collaboration tool" are TWiki, WebEx, etc. What I have in mind of developing is to develop my own. The target "market" is for software/hardware developers who will likely be working on separate projects linked by a common goal. Example: You work at a company who is designing a brand new printer. So, one man is working on the ink cartridge, another on the paper feed, one on the circuitry of the printer and one more is working on the drivers. What I would like to make (unless it already exists) is a website that, upon loading, presents the user with a web that has each project within it's own bubble, graphically. These bubbles would all be linked to the central bubble of "[Company Name]". Upon selecting an individual bubble the browser would focus and zoom in on that project bubble and expand more information (in bullets or with more affiliated bubbles) about subprojects, progress, setbacks, etc. Then, at a terminal "node" (i.e. a bubble with no sub-bubbles) a selection would then load a page with information relevant to that node. That's a lot of monologue. In short, I want to know how I might approach this. My background is with algorithmic use of Python and C++. I've never done interactive web design like this; though, I have gone through the W3C tutorials on HTML4/5. I'm willing to learn a new language I'm just wondering which language/set of languages seem(s) most appropriate for this project. Thanks, world, for imparting your knowledge to me. An example of what the start page might look like is:

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  • NMock2.0 - how to stub a non interface call?

    - by dferraro
    Hello, I have a class API which has full code coverage and uses DI to mock out all the logic in the main class function (Job.Run) which does all the work. I found a bug in production where we werent doing some validation on one of the data input fields. So, I added a stub function called ValidateFoo()... Wrote a unit test against this function to Expect a JobFailedException, ran the test - it failed obviously because that function was empty. I added the validation logic, and now the test passes. Great, now we know the validation works. Problem is - how do I write the test to make sure that ValidateFoo() is actually called inside Job.Run()? ValidateFoo() is a private method of the Job class - so it's not an interface... Is there anyway to do this with NMock2.0? I know TypeMock supports fakes of non interface types. But changing mock libs right now is not an option. At this point if NMock can't support it, I will simply just add the ValidateFoo() call to the Run() method and test things manually - which obviously I'd prefer not to do considering my Job.Run() method has 100% coverage right now. Any Advice? Thanks very much it is appreciated. EDIT: the other option I have in mind is to just create an integration test for my Job.Run functionality (injecting to it true implementations of the composite objects instead of mocks). I will give it a bad input value for that field and then validate that the job failed. This works and covers my test - but it's not really a unit test but instead an integration test that tests one unit of functionality.... hmm.. EDIT2: IS there any way to do tihs? Anyone have ideas? Maybe TypeMock - or a better design?

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  • Designing bayesian networks

    - by devoured elysium
    I have a basic question about Bayesian networks. Let's assume we have an engine, that with 1/3 probability can stop working. I'll call this variable ENGINE. If it stops working, then your car doesn't work. If the engine is working, then your car will work 99% of the time. I'll call this one CAR. Now, if your car is old(OLD), instead of not working 1/3 of the time, your engine will stop working 1/2 of the time. I'm being asked to first design the network and then assign all the conditional probabilities associated with the table. I'd say the diagram of this network would be something like OLD -> ENGINE -> CAR Now, for the conditional probabilities tables I did the following: OLD |ENGINE ------------ True | 0.50 False | 0.33 and ENGINE|CAR ------------ True | 0.99 False | 0.00 Now, I am having trouble about how to define the probabilities of OLD. In my point of view, old is not something that has a CAUSE relationship with ENGINE, I'd say it is more a characteristic of it. Maybe there is a different way to express this in the diagram? If the diagram is indeed correct, how would I go to make the tables? Thanks

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  • Dojo 1.8: Getting dest.appendChild is not a function while rendering a custom template

    - by Jim Pedid
    After adding in the WidgetsInTemplateMixin, I am receiving an error dest.appendChild is not a function In the documentation, it claims that there will be an error if this.containerNode is not able to contain any child objects. However, I have marked the containerNode attachment point for a div with dojo type "dijit/layout/ContentPane". Can anyone explain to me why this isn't working? Here is the Template file <div class="${baseClass}"> <div class="${baseClass}Container" data-dojo-type="dijit/layout/BorderContainer" data-dojo-props="design: 'headline'"> <div data-dojo-type="dijit/layout/ContentPane" data-dojo-props="region: 'top'"> Top </div> <div data-dojo-type="dijit/layout/ContentPane" data-dojo-props="region: 'center'" data-dojo-attach-point="containerNode"> </div> <div data-dojo-type="dijit/layout/ContentPane" data-dojo-props="region: 'leading', splitter: true"> Sidebar </div> </div> </div> Here is the javascript definition define([ "dojo/_base/declare", "dijit/_WidgetBase", "dijit/_OnDijitClickMixin", "dijit/layout/BorderContainer", "dijit/layout/ContentPane", "dijit/layout/TabContainer", "dijit/_TemplatedMixin", "dijit/_WidgetsInTemplateMixin", "dojo/text!./templates/MainContainer.html" ], function (declare, _WidgetBase, _OnDijitClickMixin, BorderContainer, ContentPane, TabContainer, _TemplatedMixin, _WidgetsInTemplateMixin, template) { return declare([_WidgetBase, _OnDijitClickMixin, _TemplatedMixin, _WidgetsInTemplateMixin], { templateString:template, baseClass:"main" }); }); The custom widget defined declaratively <div data-dojo-type="main/ui/MainContainer" data-dojo-props="title: 'Main Application'"> Hello Center! </div>

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  • What is actually happening to this cancelled HTTP request?

    - by Brian Schroth
    When a user takes a particular action on a page, an AJAX call is made to save their data. Unfortunately, this call is synchronous as they need to wait to see if the data is valid before being allowed to continue. Obviously, this eliminates a lot of the benefit of using Asynchronous Javascript And XML, but that's a subject for another post. That's the design I'm working with. The request is made using the dojo.xhrPost function, with a 60s timeout parameter, and the error handler redirects to an error page. What I am finding in testing is that in Firefox, if I initiate the ajax request and then press ESC, the page hangs waiting for a response, and then eventually after exactly 90s (not 60s, the function's timeout), the error handler will kick in and redirect to the error page. I expected this to happen, but either immediately as soon as the request was cancelled, or after 60s due to the timeout value being 60s. What I don't understand is why is it 90s? What is actually happening under the hood when the user cancels their request in Firefox, and how does it differ from IE, where everything works fine exactly the same as if the request had not been cancelled? Is the 90s related to any user-configurable browser settings?

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  • PocketPC c++ windows message processing recursion problem

    - by user197350
    Hello, I am having a problem in a large scale application that seems related to windows messaging on the Pocket PC. What I have is a PocketPC application written in c++. It has only one standard message loop. while (GetMessage (&msg, NULL, 0, 0)) { { TranslateMessage (&msg); DispatchMessage (&msg); } } We also have standard dlgProc's. In the switch of the dlgProc, we will call a proprietary 3rd party API. This API uses a socket connection to communicate with another process. The problem I am seeing is this: whenever two of the same messages come in quickly (from the user clicking the screen twice too fast and shouldn't be) it seems as though recursion is created. Windows begins processing the first message, gets the api into a thread safe state, and then jumps to process the next (identical ui) message. Well since the second message also makes the API call, the call fails because it is locked. Because of the design of this legacy system, the API will be locked until the recursion comes back out (which also is triggered by the user; so it could be locked the entire working day). I am struggling to figure out exactly why this is happening and what I can do about it. Is this because windows recognizes the socket communication will take time and preempts it? Is there a way I can force this API call to complete before preemption? Is there a way I can slow down the message processing or re-queue the message to ensure the first will execute (capturing it and doing a PostMessage back to itself didnt work). We don't want to lock the ui down while the first call completes. Any insight is greatly appreciated! Thanks!!

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  • Correct way to trigger object clone/memento when property changes

    - by Jay
    Hi, I have a big doubt about the correct way to save an object state (clone object), if necessary to rollback the changes, when a property has changed. I know that the IEditableObject interface exists for those cases but during some tests the BeginEdit would just fire like crazy (I have a DataGrid whose values can be edited but I won't need to keep the state of the object in these cases). I'm following the MVP design pattern in my project and the view's DataContext is a wrapper of my presenter.Let's say I have a CheckBox/TextBox in my UI and when that textbox's value changes, the property bound in the wrapper gets set.Currently, before setting the new value i'm raising an event to the presenter (something like PropertyChanging) that clones my wrapper. I'm doing this because I don't think that job should be done by the wrapper itself but by the presenter.Is this a correct approach? Raising the event is an acceptable solution? I thought of other possible ideas: Interface between presenter and wrapper; Use explicit binding and trigger the binding after saving object's state; What is your opinion about the best way to do this? Should I just keep IEditableObject, is this the best way? Best Regards

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  • Magento - Show Custom Attributes in Grouped Product table.

    - by greencoconut
    I need to find a way to show the value of a custom attribute in place of the "Product Name" shown in the image below. I'm working with /app/design/frontend/default/defaultx/template/catalog/product/view/type/grouped.php The code below doesn't work(the custom attribute is yearmade): <?php if (count($_associatedProducts)): ?> <?php foreach ($_associatedProducts as $_item): ?> <tr> <td><?php echo $this->htmlEscape($_item->getYearmade()) ?></td> Any help would be appreciated. EDIT: So the answer turned out to be quite simple. You see what I failed to mention above was that there was indeed output... but that it was just a number (eg: 52). Turns out this was the ID for that custom attribute value (It was a Dropdown type of custom attribute). So in summary This works for custom attributes of type text: echo $this->htmlEscape($_item->getYearmade()) But for all other types of custom attribute (I think), the following should be used: echo $this->htmlEscape($_item->getAttributeText('yearmade')) I would not have discovered this without the most excellent answer provided by Alan Storm, below. Thank you sir.

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  • How can I test this SQL Server performance Utility?

    - by Martin Smith
    As part of my MSc I need to do a three month project later this year. I have decided to do something which will likely be useful for me in the workplace and spend the time getting to understand SQL Server internals. The deliverable for this project will be a performance advisor looking at a variety of different rules. Some static such as finding redundant indexes, some more dynamic such as using XEvents to find outlying invocations of stored procedure execution times when certain parameters are passed. I am struggling to come up with a good way of testing this though. I can obviously design a "bad" database and a synthetic workload that my tool will pick up issues on but I also need to demonstrate that it has real world utility. Looking at the self tuning database literature it is common to use TPC benchmarks but I've had a look at the TPCC site and it looks very time consuming to implement and not that good a fit to my project's testing needs in any event (I would still be able to "rig" it by the decisions I made on indexing or physical architecture). Plan A would be to find willing beta tester(s) but in the event that isn't possible I will need a fallback plan. The best idea I have come up with so far is to use the various MS sample applications as examples of real world applications. e.g. http://msftdpprodsamples.codeplex.com/ http://www.asp.net/community/projects/ Does anyone have any better suggestions?

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  • Small-o(n^2) implementation of Polynomial Multiplication

    - by AlanTuring
    I'm having a little trouble with this problem that is listed at the back of my book, i'm currently in the middle of test prep but i can't seem to locate anything regarding this in the book. Anyone got an idea? A real polynomial of degree n is a function of the form f(x)=a(n)x^n+?+a1x+a0, where an,…,a1,a0 are real numbers. In computational situations, such a polynomial is represented by a sequence of its coefficients (a0,a1,…,an). Assuming that any two real numbers can be added/multiplied in O(1) time, design an o(n^2)-time algorithm to compute, given two real polynomials f(x) and g(x) both of degree n, the product h(x)=f(x)g(x). Your algorithm should **not** be based on the Fast Fourier Transform (FFT) technique. Please note it needs to be small-o(n^2), which means it complexity must be sub-quadratic. The obvious solution that i have been finding is indeed the FFT, but of course i can't use that. There is another method that i have found called convolution, where if you take polynomial A to be a signal and polynomial B to be a filter. A passed through B yields a shifted signal that has been "smoothed" by A and the resultant is A*B. This is supposed to work in O(n log n) time. Of course i am completely unsure of implementation. If anyone has any ideas of how to achieve a small-o(n^2) implementation please do share, thanks.

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  • Can Castle.Windsor do automatic resolution of concrete types

    - by Anthony
    We are evaluating IoC containers for C# projects, and both Unity and Castle.Windsor are standing out. One thing that I like about Unity (NInject and StructureMap also do this) is that types where it is obvious how to construct them do not have to be registered with the IoC Container. Is there way to do this in Castle.Windsor? Am I being fair to Castle.Windsor to say that it does not do this? Is there a design reason to deliberately not do this, or is it an oversight, or just not seen as important or useful? I am aware of container.Register(AllTypes... in Windsor but that's not quite the same thing. It's not entirely automatic, and it's very broad. To illustrate the point, here are two NUnit tests doing the same thing via Unity and Castle.Windsor. The Castle.Windsor one fails. : namespace SimpleIocDemo { using NUnit.Framework; using Castle.Windsor; using Microsoft.Practices.Unity; public interface ISomeService { string DoSomething(); } public class ServiceImplementation : ISomeService { public string DoSomething() { return "Hello"; } } public class RootObject { public ISomeService SomeService { get; private set; } public RootObject(ISomeService service) { SomeService = service; } } [TestFixture] public class IocTests { [Test] public void UnityResolveTest() { UnityContainer container = new UnityContainer(); container.RegisterType<ISomeService, ServiceImplementation>(); // Root object needs no registration in Unity RootObject rootObject = container.Resolve<RootObject>(); Assert.AreEqual("Hello", rootObject.SomeService.DoSomething()); } [Test] public void WindsorResolveTest() { WindsorContainer container = new WindsorContainer(); container.AddComponent<ISomeService, ServiceImplementation>(); // fails with exception "Castle.MicroKernel.ComponentNotFoundException: // No component for supporting the service SimpleIocDemo.RootObject was found" // I could add // container.AddComponent<RootObject>(); // but that approach does not scale RootObject rootObject = container.Resolve<RootObject>(); Assert.AreEqual("Hello", rootObject.SomeService.DoSomething()); } } }

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  • Comparable and Comparator contract with regards to null

    - by polygenelubricants
    Comparable contract specifies that e.compareTo(null) must throw NullPointerException. From the API: Note that null is not an instance of any class, and e.compareTo(null) should throw a NullPointerException even though e.equals(null) returns false. On the other hand, Comparator API mentions nothing about what needs to happen when comparing null. Consider the following attempt of a generic method that takes a Comparable, and return a Comparator for it that puts null as the minimum element. static <T extends Comparable<? super T>> Comparator<T> nullComparableComparator() { return new Comparator<T>() { @Override public int compare(T el1, T el2) { return el1 == null ? -1 : el2 == null ? +1 : el1.compareTo(el2); } }; } This allows us to do the following: List<Integer> numbers = new ArrayList<Integer>( Arrays.asList(3, 2, 1, null, null, 0) ); Comparator<Integer> numbersComp = nullComparableComparator(); Collections.sort(numbers, numbersComp); System.out.println(numbers); // "[null, null, 0, 1, 2, 3]" List<String> names = new ArrayList<String>( Arrays.asList("Bob", null, "Alice", "Carol") ); Comparator<String> namesComp = nullComparableComparator(); Collections.sort(names, namesComp); System.out.println(names); // "[null, Alice, Bob, Carol]" So the questions are: Is this an acceptable use of a Comparator, or is it violating an unwritten rule regarding comparing null and throwing NullPointerException? Is it ever a good idea to even have to sort a List containing null elements, or is that a sure sign of a design error?

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  • Is using SharePoint as a intranet/extranet portal a good idea?

    - by Rob
    I work for a fortune 500 company in IT and we have developed many systems/applications to do a variety of things. We are in need of some commonality of these applications and a better portal/dashboard/landing page for these applications. So, our customers and employees would log into this portal and see all the "things" that they can do which then link to their own application. This could maybe just iframe in each application inside of this portal to keep brand and navigation consistency. We are trying to decide whether to use SharePoint 2007 or 2010 for this or develop a portal/dashboard of sorts in house. We would like this portal to look and feel very branded to our needs and really not even feel like its using SharePoint (if needed). An example is to provide our own Menu control that drives the navigation if needed. Does anyone have any pros/cons for using SharePoint in such a way? Any advice on implementation (e.g. use 2010, much easier to customize design than 2007, etc)?

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  • Programatic re-evalutation of MVVM command's "can execute" state

    - by dzs
    Hello! I'm writing a WPF application using the MVVM pattern, based on the following article: WPF Apps With The Model-View-ViewModel Design Pattern I have two buttons on my View with the buttons' "Command" property bound (with data binding) to a given instance of the RelayCommand class (see "Figure 3 The RelayCommand Class" from the article above). The RelayCommand class has support for checking whether the given command can be executed. WPF automatically disables buttons whose command cannot be executed. Each of my commands (in the ViewModel class) start a background operation, and the command cannot be executed again until the background operation is finished. The RelayCommand instances have information whether the background operation is still working or it is finished. My problem is the following: after pressing the any of the buttons, the buttons automaticaly go disabled (which is OK) because the background operation started and the command cannot be executed until it is finished, but after the operation had finished, the buttons don't go enabled automatically because their command's "can be executed" predicate is not automatically reevaluated. The reevaluation can be manually triggered by having the application loose and regain focus (by pressing ALT+TAB). After doing this trick, the buttons get enabled once again. How can I programatically reevaluate the buttons' command's "can execute" state?

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  • Problem with Silverlight 3 projects in Web Developer Express 2008

    - by MNT
    Hi, I have a strange problem when working with silverlight 3 projects in Web Developer Express 2008. Mainly, I cannot show the design view of a XAML file. Also the XAML files (markup) are shown as plain text files (No Syntax coloring & No Intellisense). However I can write an application that is compiled and run successfully. I have the following installed on my machine: Windows XP SP3 Visual Web Developer Express 2008 SP1 & .NET 3.5 SP1 SL3 Requirements I had a few problems while installing SL3 SDK & Tool for VS. I repeated the process many times until the installation succeeded. The main problem was in the "SL Tools for VS" installation where I used to get an error in the middle. My workaround was to extract the MSI file and manually run the VWDxxx installer from the extracted files. Is this the cause of the problem? Kindly advise as it's impractical to work w/o Intellisense. Thnak you

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  • Threads, Sockets, and Designing Low-Latency, High Concurrency Servers

    - by lazyconfabulator
    I've been thinking a lot lately about low-latency, high concurrency servers. Specifically, http servers. http servers (fast ones, anyway) can serve thousands of users simultaneously, with very little latency. So how do they do it? As near as I can tell, they all use events. Cherokee and Lighttpd use libevent. Nginx uses it's own event library performing much the same function of libevent, that is, picking a platform optimal strategy for polling events (like kqueue on *bsd, epoll on linux, /dev/poll on Solaris, etc). They all also seem to employ a strategy of multiprocess or multithread once the connection is made - using worker threads to handle the more cpu intensive tasks while another thread continues to listen and handle connections (via events). This is the extent of my understanding and ability to grok the thousand line sources of these applications. What I really want are finer details about how this all works. In examples of using events I've seen (and written) the events are handling both input and output. To this end, do the workers employ some sort of input/output queue to the event handling thread? Or are these worker threads handling their own input and output? I imagine a fixed amount of worker threads are spawned, and connections are lined up and served on demand, but how does the event thread feed these connections to the workers? I've read about FIFO queues and circular buffers, but I've yet to see any implementations to work from. Are there any? Do any use compare-and-swap instructions to avoid locking or is locking less detrimental to event polling than I think? Or have I misread the design entirely? Ultimately, I'd like to take enough away to improve some of my own event-driven network services. Bonus points to anyone providing solid implementation details (especially for stuff like low-latency queues) in C, as that's the language my network services are written in.

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  • NHibernate.MappingException - Troubles Shooting Checklist (no persister for)

    - by Berryl
    Here's a starter list: 1) if hbm is hand generated, is it an embedded resource? 2) if using FNH, does it pass a PerssistenceSpecification test? 3) if not using FNH, can you save and then load the persisted class? 4) more? I'm sure many of you have gotten this one at one point or another. But have you ever gotten it when you knew your mapping was set up correctly? I started getting this exception after I started using a new repository design, but only in one scenario! PersistenceSpecification tests pass, as do all repository methods (using SQLite). The scenario that leads to the exception is when legacy projects from a different db are converted to green field system. The legacy system is from a different database and has it's own session factory, which should be irrelevant because the error comes after previously unconverted Projects are retrieved and in memory. As the routine tries to save these unconverted Projects into the new database, the exception is thrown, full stack trace below. Any ideas on how to build up the trouble shooting check list and solves this problem? Cheers, Berryl === the Exception trace ===== failed: NHibernate.MappingException : No persister for: Smack.ConstructionAdmin.Domain.Model.Projects.Project at NHibernate.Impl.SessionFactoryImpl.GetEntityPersister(String entityName) at NHibernate.Impl.SessionImpl.GetEntityPersister(String entityName, Object obj) at NHibernate.Engine.ForeignKeys.IsTransient(String entityName, Object entity, Nullable`1 assumed, ISessionImplementor session) at NHibernate.Event.Default.AbstractSaveEventListener.GetEntityState(Object entity, String entityName, EntityEntry entry, ISessionImplementor source) at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.PerformSaveOrUpdate(SaveOrUpdateEvent event) at NHibernate.Event.Default.DefaultSaveOrUpdateEventListener.OnSaveOrUpdate(SaveOrUpdateEvent event) at NHibernate.Impl.SessionImpl.FireSaveOrUpdate(SaveOrUpdateEvent event) at NHibernate.Impl.SessionImpl.SaveOrUpdate(Object obj) NHibernate\Repository\FabioNHibRepository.cs(46,0): at Smack.Core.Data.NHibernate.Repository.FabioNHibRepository`1.Add(T item) LegacyConversion\LegacyBatchUpdater.cs(20,0): at Smack.ConstructionAdmin.Data.LegacyConversion.LegacyBatchUpdater.ConvertOpenLegacyProjects(ILegacyProjectDao legacyProjectDao, IProjectRepository greenProjectRepository) Data\Brownfield\ProjectBatchUpdate_SQLiteTests.cs(19,0): at Smack.ConstructionAdmin.Tests.Data.Brownfield.ProjectBatchUpdate_SQLiteTests.Test()

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  • Which java web technology to learn to develop Rich Internet Applications ?

    - by Cshah
    Hi, I have developed web applications using JSF (myfaces components). But in these days of responsive UI, JSF doesnt fare well. I m hearing a lot about AJAX, GWT, etc. So i wanted your opinion on which web technology/framework should i learn inorder to develop web applications for enterprise products. Some of the web technologies that i m hearing are: ICE Faces (With AJAX Bridge support) GWT extJS and extGWT JavaFX Apache Wicket Jquery AJAX Open laszlo Which of the above or the combination of the above would help me ? Some of the parameters on which you can rate these web technologies are: Ease of learning Maintainability of web application code Community support IDE support - Eclipse or NetBeans Off the shelf component availability (like textbox,table grids, option menus) License - Does it cost for commercial use ? User Experience - responsive UI. Shouldnt be sluggish A similar question on SO does answer my question partially. Would want more info though. EDIT: Answers collated: Based on the answers : AJAX would be the best thing to start for learning fundamentals, then learn JQUERY. Any component based frame work that can complement ajax,jquery ? Edit 2: If i had to design a web application like StackOverFlow (in java platform) which would be the best choice to learn and adopt? Wicket + Jquery, WiQuery GWT Some XYZ Faces technology(RichFaces/ICEFaces) + AJAX. Comments appreciated from some one who has worked with them and can rate them in the above mentioned parameters.

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  • ASP.NET Event delegation between user controls

    - by Ishan
    Give the following control hierarchy on a ASP.NET page: Page HeaderControl       (User Control) TitleControl       (Server Control) TabsControl       (User Control) other controls I'm trying to raise an event (or some notification) in the TitleControl that bubbles to the Page level. Then, I'd like to (optionally) register an event handler at the Page codebehind that will take the EventArgs and modify the TabsControl in the example above. The important thing to note is that this design will allow me to drop these controls into any Page and make the entire system work seamlessly if the event handler is wired up. The solution should not involve a call to FindControl() since that becomes a strong association. If no handler is defined in the containing Page, the event is still raised by TitleControl but is not handled. My basic goal is to use event-based programming so that I can decouple the user controls from each other. The event from TitleControl is only raised in some instances, and this seemed to be (in my head) the preferred approach. However, I can't seem to find a way to cleanly achieve this. Here are my (poor) attempts: Using HttpContext.Current.Items Add the EventArgs to the Items collection on TitleControl and pick it up on the TabsControl. This works but it's fundamentally hard to decipher since the connection between the two controls is not obvious. Using Reflection Instead of passing events, look for a function on the container Page directly within TitleControl as in: Page.GetType().GetMethod("TabControlHandler").Invoke(Page, EventArgs); This will work, but the method name will have to be a constant that all Page instances will have to defined verbatim. I'm sure that I'm over-thinking this and there must be a prettier solution using delegation, but I can't seem to think of it. Any thoughts?

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