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  • dynamical binding or switch/case?

    - by kingkai
    A scene like this: I've different of objects do the similar operation as respective func() implements. There're 2 kinds of solution for func_manager() to call func() according to different objects Solution 1: Use virtual function character specified in c++. func_manager works differently accroding to different object point pass in. class Object{ virtual void func() = 0; } class Object_A : public Object{ void func() {}; } class Object_B : public Object{ void func() {}; } void func_manager(Object* a) { a->func(); } Solution 2: Use plain switch/case. func_manager works differently accroding to different type pass in typedef _type_t { TYPE_A, TYPE_B }type_t; void func_by_a() { // do as func() in Object_A } void func_by_b() { // do as func() in Object_A } void func_manager(type_t type) { switch(type){ case TYPE_A: func_by_a(); break; case TYPE_B: func_by_b(); default: break; } } My Question are 2: 1. at the view point of DESIGN PATTERN, which one is better? 2. at the view point of RUNTIME EFFCIENCE, which one is better? Especailly as the kinds of Object increases, may be up to 10-15 total, which one's overhead oversteps the other? I don't know how switch/case implements innerly, just a bunch of if/else? Thanks very much!

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  • CakePHP: Interaction between different files/classes

    - by Alexx Hardt
    Hey, I'm cloning a commercial student management system. Students use the frontend to apply for lectures, uni staff can modify events (time, room, etc). The core of the app will be the algortihm which distributes the seats to students. I already asked about it here: How to implement a seat distribution algorithm for uni lectures Now, I found a class for that algorithm here: http://www.phpclasses.org/browse/file/10779.html I put the 'class GA' into app/vendors. I need to write a 'class Solution', which represents one object (a child, and later a parent for the evolutionary process). I'll also have to write functions mutate(), crossover() and fitness(). fitness calculates a score of a solution, based on if there are overbooked courses etc; crossover() is the crazy monkey sex function which produces a child from two parents, and mutate() modifies a child after crossover. Now, the fitness()-function needs to access a few related models, and their find()-functions. It evaluates a solution's fitness by checking e.g. if there are overbooked courses, or unfulfilled wishes, and penalizes that. Where would I put the ga.php, solution.php and the three functions? ga.php has to access the functions, but the functions have to access the models. I also don't want to call any App::import()'s from within the fitness()-function, because it gets called many thousand times when the algorithm runs. Hope someone can help me. Thanks in advance =)

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  • Strange(?) Opera Floating

    - by SkaveRat
    I have some strange floating behaviour on opera (IE f's up completely different, but that's for later). I'm floating the i-icons to the right. It works nicely on Fx and WebKit, but opera shifts the icons down a bit. Anyone got an idea how this happenes? CSS: .dataRow { margin: 5px 0; clear:right; } .dataRow label{ display: block; float:left; width: 160px; vertical-align: middle; font-size: 80%; } .dataGroup a img { border:0;float:right; position:relative; right:0; } .dataGroup a:hover { background:#EBEDC7; text-decoration:none; } .dataGroup a.tooltip span { display:none; padding:2px 3px; margin-top:20px; width:100px; font-size: 80%; } .dataGroup a.tooltip:hover span { display:inline; position:absolute; border:1px solid #632D11; background:#C2BD6C; color:#fff; } HTML: <fieldset class="dataGroup"> <div class="dataRow"><label>Foobar:</label> <input name="foobar" size="10" value="somedata" /> <a href="#" class="tooltip"><img src="/img/admin/information.png"/><span>Tooltip Info</span></a></div> </fieldset>

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  • Jquery selectors question

    - by Ben
    Hi all, I am not an expert at jquery but trying to get a menu to work. Basically, I have a menu made of up to 3 levels of nested lists. The first level has a little arrow has a background image that opens or close when opening the first level list. Any other nested lists don't need to have the background image. My script opens the menu when you click on it and is also supposed to switch the first level list from a class "inactive" to a class "active". Here is the script: $(document).ready(function(){ $("#left-navigation-holder ul.level1 li.inactive").toggle(function(){ $(this).addClass("active"); }, function () { $(this).removeClass("active"); }); $("#left-navigation-holder li a").click(function(){ menu = $(this).parent('li').children('ul'); menu.toggle(); }); }); The problem is that the toggle function also happens when clicking on second and third level lists causing the arrows to toggle even if the first level list isn't clicked on. I thought using $("#left-navigation-holder ul.level1 li.inactive").toggle would limit the function to the first level list with a class "inactive". Any help would be really appreciated. Ben

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  • Folder permission and submit button

    - by bob
    I want to create a simple installation script. Below are simple code. <ul> <?php function check_perms($path,$perm) { clearstatcache(); $configmod = substr(sprintf('%o', fileperms($path)), -4); $css = (($configmod != $perm) ? " class='error r2'" : " class='none'"); echo "<li".$css.">\n"; echo '<span style="float:left; padding-right:20px;">'.$path.'</span>'; echo '<span style="float:right; width:100px; text-align:right;"> <strong>'.$perm.'</strong></span>'; echo '<span style="float:right; padding-right:100px;"><strong>'.$configmod.'</strong></span>'; echo '<div class="clear"></div>'; echo "</li>"; } check_perms("config.php","0777"); check_perms("themes","0777"); check_perms("themes/images","0777"); check_perms("useruploads","0777"); ?> </ul> How to make if all file and folder is valid permission to 777 will appear Submit button. <input type='submit' name='submit' value='Submit' /> If there still have incorrect permission do not show the Submit button Let me know.

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  • How To Update EF 4 Entity In ASP.NET MVC 3?

    - by Jason Evans
    Hi there. I have 2 projects - a class library containing an EDM Entity Framework model and a seperate ASP.NET MVC project. I'm having problems with how your suppose to edit and save changes to an entity using MVC. In my controller I have: public class UserController : Controller { public ActionResult Edit(int id) { var rep = new UserRepository(); var user = rep.GetById(id); return View(user); } [HttpPost] public ActionResult Edit(User user) { var rep = new UserRepository(); rep.Update(user); return View(user); } } My UserRepository has an Update method like this: public void Update(User user) { using (var context = new PDS_FMPEntities()) { context.Users.Attach(testUser); context.ObjectStateManager.ChangeObjectState(testUser, EntityState.Modified); context.SaveChanges(); } } Now, when I click 'Save' on the edit user page, the parameter user only contains two values populated: Id, and FirstName. I take it that is due to the fact that I'm only displaying those two properties in the view. My question is this, if I'm updating the user's firstname, and then want to save it, what am I suppose to do about the other User properties which were not shown on the view, since they now contain 0 or NULL values in the user object? I've been reading a lot about using stub entities, but I'm getting nowhere fast, in that none of the examples I've seen actually work. i.e. I keep getting EntityKey related exceptions. Can someone point me to a good tutorial/example of how to update EF 4 entities using a repository class, called by an MVC front-end? Cheers. Jas.

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  • In Fluent NHibernate, how would I map the following domain models?

    - by Brandon
    I have a user class that looks something like this public class User { public virtual int Id { get; set; } public virtual long ValueA { get; set; } public virtual int? ValueB { get; set; } } ValueA is automatically assigned by the system. It is used in a lookup that would map to UserClass. However, if a value for ValueB exists, then it would do the lookup for UserClass in a different way. Right now the way I handle it is to get the User and then perform a separate lookup each time. return user.ValueB.HasValue ? Find(user.ValueB.Value) : Find(user.ValueA); Is there any way to make Fluent NHibernate do this for me so I can have UserClass as a property on the User class instead of having to do the lookup separately? I was thinking of the ComponentMap but I'm not sure how to make it account for the two possible lookup values.

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  • Two entities with @ManyToOne should join the same table

    - by Ivan Yatskevich
    I have the following entities Student @Entity public class Student implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; //getter and setter for id } Teacher @Entity public class Teacher implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; //getter and setter for id } Task @Entity public class Task implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO) private Long id; @ManyToOne(optional = false) @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "student_id") }) private Student author; @ManyToOne(optional = false) @JoinTable(name = "student_task", inverseJoinColumns = { @JoinColumn(name = "teacher_id") }) private Teacher curator; //getters and setters } Consider that author and curator are already stored in DB and both are in the attached state. I'm trying to persist my Task: Task task = new Task(); task.setAuthor(author); task.setCurator(curator); entityManager.persist(task); Hibernate executes the following SQL: insert into student_task (teacher_id, id) values (?, ?) which, of course, leads to null value in column "student_id" violates not-null constraint Can anyone explain this issue and possible ways to resolve it?

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  • jQuery: Trouble with draggable across cloned elements

    - by Rosarch
    I'm trying to implement: User drags a draggable li to a droppable li. The original li is no longer draggable A new li is cloned from the original li, and is appended to the droppable li. I can't get it to work. function moveToTerm(original_course, helper, term) { var cloned_course = original_course.clone(true); original_course.addClass('already-scheduled'); original_course.draggable('disable'); cloned_course.draggable(); cloned_course.appendTo(term).hide().fadeIn('slow'); } This works fine, except now the cloned_course is not draggable. A droppable li: <li class="term ui-droppable"> <strong>Fall 2010</strong> <li class="course">Computing Cultures</li> <!-- this course was just dropped. I want it to be draggable but it's not --> <li class="course ui-draggable" style="display: list-item;">New Media and Society</li> </li> What am I doing wrong?

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  • Where do I put the logic of my MFC program?

    - by Matthew
    I created an application core, in C++, that I've compiled into a static library in Visual Studio. I am now at the process of writing a GUI for it. I am using MFC to do this. I figured out how to map button presses to execute certain methods of my application core's main class (i.e. buttons to have it start and stop). The core class however, should always be sampling data from an external source every second or two. The GUI should then populate some fields after each sample is taken. I can't seem to find a spot in my MFC objects like CDialog that I can constantly check to see if my class has grabbed the data.. then if it has put that data into some of the text boxes. A friend suggested that I create a thread on the OnInit() routine that would take care of this, but that solution isn't really working for me. Is there no spot where I can put an if statement that keeps being called until the program quits? i.e. if( coreapp.dataSampleReady() ) { // put coreapp.dataItem1() in TextBox1 // set progress bar to coreapp.dataItem2() // etc. // reset dataSampleReady }

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  • How can I bind a List as ItemSource to ListView in XAML?

    - by Jonas
    I'm learning WPF and would like to have a collection similar to a LinkedList, to where I can add and remove strings. And I want to have a ListView that listen to that collection with databinding. How can I do bind a simple list collection to a ListView in XAML? My idea (not working) is something like this: <Window x:Class="TestApp.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <Window.Resources> <LinkedList x:Key="myList"></LinkedList> //Wrong <Window.Resources> <Grid> <ListView Height="100" HorizontalAlignment="Left" Margin="88,134,0,0" Name="listView1" VerticalAlignment="Top" Width="120" ItemsSource="{Binding Source={StaticResource myList}}"/> //Wrong </Grid> </Window> All my code (updated version, not working): <Window x:Class="TestApp.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="MainWindow" Height="350" Width="525"> <Grid> <TextBox Height="23" HorizontalAlignment="Left" Margin="12,12,0,0" Name="textBox1" VerticalAlignment="Top" Width="120" /> <Button Content="Button" Height="23" HorizontalAlignment="Right" Margin="0,12,290,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" /> <ListView Height="100" HorizontalAlignment="Left" Margin="88,134,0,0" Name="listView1" VerticalAlignment="Top" Width="120" ItemsSource="{Binding myList}"/> </Grid> </Window> C#-code: namespace TestApp { public partial class MainWindow : Window { ObservableCollection<string> myList = new ObservableCollection<string>(); public MainWindow() { InitializeComponent(); myList.Add("first string"); } private void button1_Click(object sender, RoutedEventArgs e) { myList.Add(textBox1.Text); textBox1.Text = myList.Count+"st"; } } }

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  • What is the appropriate HTML 5 element for a hero unit/showcase?

    - by deb
    A lot of marketing and content-heavy sites showcase the page's primary content using large text and/or images, sometimes with a slider, containing a call to action for signing up for a service, or downloading an app, etc.. I'm not sure what this design element is called, I got the term hero unit from twitter bootstrap: http://twitter.github.com/bootstrap/components.html#typography I think most of you know what I'm trying to describe... If it's not clear I can add screenshots or links to this question. I looked at a few different sites, and some put this hero unit inside a ASIDE element, others use SECTION, ARTICLE and even HEADER. Using twitter bootstrap as an example again: <header class="jumbotron masthead"> <div class="inner"> <h1>Bootstrap, from Twitter</h1> <p>Simple and flexible HTML, CSS, and Javascript for popular user interface components and interactions.</p> <p class="download-info"> Is HEADER the most appropriate tag for this type of content? Or should I use ASIDE, ARTICLE or SECTION?

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  • many to many and integrity when saving the null

    - by user369759
    I have two classes Software, Tag - they are related by ManyToMany. We CAN NOT create Software without putting the Tag to it. I want to write a test which check that: @Test public void createSoftwareWithNullTags() { List<Tag> tags = null; Software software = new Software("software1", "description1", tags); try { software.save(); fail("tags should not be null"); } catch (Exception ex) { // NEVER COME HERE !!! } } So, this test fails. I guess it is not good test for that case - because it even do not try to SAVE data to SOFTWARE_TAG table. Of course i could do validation manually but i want implement it with hibernate, using some annotation or something. Is it possible? Or how would you do this? My entities: @Entity public class Tag extends Model { public String title; public Tag(String title) { this.title = title; } @ManyToMany( cascade = {CascadeType.ALL}, mappedBy = "tags", targetEntity = Software.class ) public List<Software> softwares; } @Entity public class Software extends Model { public String title; public String description; @ManyToOne(optional = false) public Author author; @ManyToMany(cascade = CascadeType.ALL) @JoinTable( name = "SOFTWARE_TAG", joinColumns = @JoinColumn(name = "Software_id"), inverseJoinColumns = @JoinColumn(name = "Tag_id") ) public List<Tag> tags; public Software(String title, String description, Author author, List<Tag> tags) { this.title = title; this.description = description; this.author = author; this.tags = tags; } }

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  • wpf observableCollection

    - by Asha
    I have an ObservableCollection which is dataContext for my treeview when I try to remove an Item from ObservableCollection I will get an error that Object reference not set to an instance of an object . can you please tell me why this error is happening and what is the solution thanks EDIT 1: The code is something like : class MyClass : INotifyPropertyChanged { //my class code here } public partial class UC_myUserControl : UserControl { private ObservableCollection<MyClass> myCollection = new ObservableCollection<MyClass>(); private void UserControl_Loaded(object sender, RoutedEventArgs e) { myCollection.add(new myClass); myTreeView.DataContext = myCollection ; } private void deleteItem() { myCollection.RemoveAt(0); //after removing I get error Which I guess should be something related //to interface update but I don't know how can I solve it } } Exception Detail : System.NullReferenceException was unhandled Message="Object reference not set to an instance of an object." Source="PresentationFramework" EDIT 3: I have a style which is for my treeitem to keep the treeitems expanded <Style TargetType="TreeViewItem"> <Setter Property="IsExpanded" Value="True" /> </Style> and with commenting this part I wont get any error !!! Now I want to change my question to why having this style is causing error ?

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  • How can I refactor this to work without breaking the pattern horribly?

    - by SnOrfus
    I've got a base class object that is used for filtering. It's a template method object that looks something like this. public class Filter { public void Process(User u, GeoRegion r, int countNeeded) { List<account> selected = this.Select(u, r, countNeeded); // 1 List<account> filtered = this.Filter(selected, u, r, countNeeded); // 2 if (filtered.Count > 0) { /* do businessy stuff */ } // 3 if (filtered.Count < countNeeded) this.SendToSuccessor(u, r, countNeeded - filtered) // 4 } } Select(...), Filter(...) are protected abstract methods and implemented by the derived classes. Select(...) finds objects in the based on x criteria, Filter(...) filters those selected further. If the remaining filtered collection has more than 1 object in it, we do some business stuff with it (unimportant to the problem here). SendToSuccessor(...) is called if there weren't enough objects found after filtering (it's a composite where the next class in succession will also be derived from Filter but have different filtering criteria) All has been ok, but now I'm building another set of filters, which I was going to subclass from this. The filters I'm building however would require different params and I don't want to just implement those methods and not use the params or just add to the param list the ones I need and have them not used in the existing filters. They still perform the same logical process though. I also don't want to complicated the consumer code for this (which looks like this) Filter f = new Filter1(); Filter f2 = new Filter2(); Filter f3 = new Filter3(); f.Sucessor = f2; f2.Sucessor = f3; /* and so on adding filters as successors to previous ones */ foreach (User u in users) { foreach (GeoRegion r in regions) { f.Process(u, r, ##); } } How should I go about it?

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  • Validation on ManyToManyField before Save in Models.py

    - by Heyl1
    I have the following models: class Application(models.Model): users = models.ManyToManyField(User, through='Permission') folder = models.ForeignKey(Folder) class Folder(models.Model): company = models.ManyToManyField(Compnay) class UserProfile(models.Model): user = models.OneToOneField(User, related_name='profile') company = models.ManyToManyField(Company) What I would like to do is to check whether one of the users of the Application has the same company as the Application (via Folder). If this is the case the Application instance should not be saved. The problem is that the ManyToManyFields aren't updated until after the 'post-save' signal. The only option seems to be the new m2m_changed signal. But I'm not sure how I then roll back the save that has already happened. Another option would be to rewrite the save function (in models.py, because I'm talking about the admin here), but I'm not sure how I could access the manytomanyfield content. Finally I've read something about rewriting the save function in the admin of the model in admin.py, however I still wouldn't know how you would access the manytomanyfield content. I have been searching for this everywhere but nothing I come across seems to work for me. If anything is unclear, please tell me. Thanks for your help! Heleen

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  • Select ID in table ...

    - by Kris-I
    Hello, I have this code <% foreach (var item in Model.List) { %> <tr> <td><%: item.LastName %></td> <td><%: item.FirstName %></td> <td><%: item.IsEnable %></td> <td><a href="#" class="CustomerEdit">Edit</a></td> <td><a href="#" class="CustomerDetail">Detail</a></td> <td><a href="#" class="CustomerDelete">Delete</a></td> </tr> <% } %> <script language="javascript" type="text/javascript"> $(document).ready(function () { $(".CustomerEdit").click(function () { alert("blabla"); //need id here }); }); </script> It's not in the code but I have an "Item.Id", it's not place anywhere because I don't know where place it ;-). I'd like when I click on the "Edit" hyperlink get the id (item.Id) of the current line. Any idea ? Thanks,

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  • Vertically Aligning Divs

    - by Crays
    Hi, i'm trying to make a small username and password input box. I would like to ask how do you vertically align a div? What i have is a <div id="Login" class="BlackStrip floatright"> <div id="Username" class="floatleft">Username<br>Password</div> <div id="Form" class="floatleft"> <form action="" method="post"> <input type="text" border="0"><br> <input type="password" border="0"> </form> </div> </div> and how can i make the div with id Username and Form to vertically align itself to the center? I tried putting vertical-align: middle; in css for the div with id Login. But doesn't seem to work. Any help would be appreciated. Thanks.

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  • varargs in lambda functions in Python

    - by brain_damage
    Is it possible a lambda function to have variable number of arguments? For example, I want to write a metaclass, which creates a method for every method of some other class and this newly created method returns the opposite value of the original method and has the same number of arguments. And I want to do this with lambda function. How to pass the arguments? Is it possible? class Negate(type): def __new__(mcs, name, bases, _dict): extended_dict = _dict.copy() for (k, v) in _dict.items(): if hasattr(v, '__call__'): extended_dict["not_" + k] = lambda s, *args, **kw: not v(s, *args, **kw) return type.__new__(mcs, name, bases, extended_dict) class P(metaclass=Negate): def __init__(self, a): self.a = a def yes(self): return True def maybe(self, you_can_chose): return you_can_chose But the result is totally wrong: >>>p = P(0) >>>p.yes() True >>>p.not_yes() # should be False Traceback (most recent call last): File "<pyshell#150>", line 1, in <module> p.not_yes() File "C:\Users\Nona\Desktop\p10.py", line 51, in <lambda> extended_dict["not_" + k] = lambda s, *args, **kw: not v(s, *args, **kw) TypeError: __init__() takes exactly 2 positional arguments (1 given) >>>p.maybe(True) True >>>p.not_maybe(True) #should be False True

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  • How to mimic polymorphism in classes with template methods (c++)?

    - by davide
    in the problem i am facing i need something which works more or less like a polymorphic class, but which would allow for virtual template methods. the point is, i would like to create an array of subproblems, each one being solved by a different technique implemented in a different class, but holding the same interface, then pass a set of parameters (which are functions/functors - this is where templates jump up) to all the subproblems and get back a solution. if the parameters would be, e.g., ints, this would be something like: struct subproblem { ... virtual void solve (double& solution, double parameter)=0; } struct subproblem0: public subproblem { ... virtual void solve (double& solution, double parameter){...}; } struct subproblem1: public subproblem { ... virtual void solve (double* solution, double parameter){...}; } int main{ subproblem problem[2]; subproblem[0] = new subproblem0(); subproblem[1] = new subproblem1(); double argument0(0), argument1(1), sol0[2], sol1[2]; for(unsigned int i(0);i<2;++i) { problem[i]->solve( &(sol0[i]) , argument0); problem[i]->solve( &(sol1[i]) , argument1); } return 0; } but the problem is, i need the arguments to be something like Arg<T1,T2> argument0(f1,f2) and thus the solve method to be something of the likes of template<T1,T2> solve (double* solution, Arg<T1,T2> parameter) which cant obviously be declared virtual ( so cant be called from a pointer to the base class)... now i'm pretty stuck and don't know how to procede...

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  • How to read a parameter passed to a facelet from a backing bean

    - by Antonio
    Hi, I've written a facelet, and a corresponding backing bean, that implements user management (addition, deletion and so on). I'd want to be able to perform some custom processing when, for instance, a new user is added. There is a "create" button in the facelet, whose click event is handled by its backing bean. At the end of the event handler, I'd want to be able to call a method of another backing bean, which is not known because ideally the facelet can be used in several pages, with different custom processing. I thought to implement this feature by providing to the facelet a backing bean name and a method name, like this: <myfacelet:subaccounts backingBean="myBackingBean" createListener="createListener" /> and at the end of the event handler call #{myBackingBean.createListener} someway. I'm using this method (along with some overloads) to obtain a MethodExpression: protected MethodExpression getMethodExpression(String beanName, String methodName, Class<?> expectedReturnType, Class<?>[] expectedParamTypes) { ExpressionFactory expressionFactory; MethodExpression method; ELContext elContext; String el; el = String.format("#{%s['%s']}", beanName, methodName); expressionFactory = getApplication().getExpressionFactory(); elContext = getFacesContext().getELContext(); method = expressionFactory.createMethodExpression(elContext, el, expectedReturnType, expectedParamTypes); return method; } and the click event handler should look like: public void saveSubaccountListener(ActionEvent event) { MethodExpression method; ... method = getMethodExpression( "backingBean", "createSubaccountListener", SubuserBean.class); if (method != null) method.invoke( getFacesContext().getELContext(), new Object[] { _editedSubuser }); } That works fine as long as I provide an existing bean name (myBackingBean), but if I use backingBean the invoke() doesn't work due to the following error: javax.el.PropertyNotFoundException: Target Unreachable, identifier 'backingBean' resolved to null Is there a way I can retrieve from the facelet backing bean the value of a parameter that has been passed to the facelet? In my case, the value of backingBean, which should be myBackingBean? I've searched for and tried different solutions, but with no luck yet.

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  • Why does the entity framework need an ICollection for lazy loading?

    - by Akk
    I want to write a rich domain class such as public class Product { public IEnumerable<Photo> Photos {get; private set;} public void AddPhoto(){...} public void RemovePhoto(){...} } But the entity framework (V4 code first approach) requires an ICollection type for lazy loading! The above code no longer works as designed since clients can bypass the AddPhoto / RemovePhoto method and directly call the add method on ICollection. This is not good. public class Product { public ICollection<Photo> Photos {get; private set;} //Bad public void AddPhoto(){...} public void RemovePhoto(){...} } It's getting really frustrating trying to implement DDD with the EF4. Why did they choose the ICollection for lazy loading? How can i overcome this? Does NHibernate offer me a better DDD experience?

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  • pure/const functions in C++

    - by Albert
    Hi, I'm thinking of using pure/const functions more heavily in my C++ code. (pure/const attribute in GCC) However, I am curious how strict I should be about it and what could possibly break. The most obvious case are debug outputs (in whatever form, could be on cout, in some file or in some custom debug class). I probably will have a lot of functions, which don't have any side effects despite this sort of debug output. No matter if the debug output is made or not, this will absolutely have no effect on the rest of my application. Or another case I'm thinking of is the use of my own SmartPointer class. In debug mode, my SmartPointer class has some global register where it does some extra checks. If I use such an object in a pure/const function, it does have some slight side effects (in the sense that some memory probably will be different) which should not have any real side effects though (in the sense that the behaviour is in any way different). Similar also for mutexes and other stuff. I can think of many complex cases where it has some side effects (in the sense of that some memory will be different, maybe even some threads are created, some filesystem manipulation is made, etc) but has no computational difference (all those side effects could very well be left out and I would even prefer that). How does it work out in practice? If I mark such functions as pure/const, could it break anything (considering that the code is all correct)?

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  • How are declared private ivars different from synthesized ivars?

    - by lemnar
    I know that the modern Objective-C runtime can synthesize ivars. I thought that synthesized ivars behaved exactly like declared ivars that are marked @private, but they don't. As a result, come code compiles only under the modern runtime that I expected would work on either. For example, a superclass: @interface A : NSObject { #if !__OBJC2__ @private NSString *_c; #endif } @property (nonatomic, copy) NSString *d; @end @implementation A @synthesize d=_c; - (void)dealloc { [_c release]; [super dealloc]; } @end and a subclass: @interface B : A { #if !__OBJC2__ @private NSString *_c; #endif } @property (nonatomic, copy) NSString *e; @end @implementation B @synthesize e=_c; - (void)dealloc { [_c release]; [super dealloc]; } @end A subclass can't have a declared ivar with the same name as one of its superclass's declared ivars, even if the superclass's ivar is private. This seems to me like a violation of the meaning of @private, since the subclass is affected by the superclass's choice of something private. What I'm more concerned about, however, is how should I think about synthesized ivars. I thought they acted like declared private ivars, but without the fragile base class problem. Maybe that's right, and I just don't understand the fragile base class problem. Why does the above code compile only in the modern runtime? Does the fragile base class problem exist when all superclass instance variables are private?

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  • IE7: container of hidden Div displays incorrectly

    - by dmr
    There is a search box div that contains a boxhead div and a boxbody div. Inside the boxbody div, there is a searchToggle div. When the user clicks a certain link on the page, the display style property of the searchToggle div is toggled between block and none. The 2 background-images for the body of the search box are set via the css of the searchBox div and the boxbody div. In IE7, when the searchToggle div is hidden, the background-image from the searchBox div extends on the left more than it should. It shows up correctly when the display of the searchToggle div is block. Everything show up correctly, in both cases in IE8 and FF. Any ideas why this is happening? The relevant HTML: <div class="searchBox"> <div class="boxhead"> <h2></h2> </div> <div class="boxbody"> <div id="searchToggle" name="searchToggle"> </div> </div> </div> The relevant CSS: .searchBox { margin: 0 auto; width: 700px; background: url(/images/myImageRight-r.gif) no-repeat bottom right; font-size: 100%; text-align: left; overflow: hidden; } .boxbody { margin: 0; padding: 5px 30px 31px; background-image: url(/images/myImageLeft.gif); background-repeat: no-repeat; background-position: left bottom; }

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