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  • whats the name of this pattern?

    - by Wes
    I see this a lot in frameworks. You have a master class which other classes register with. The master class then decides which of the registered classes to delegate the request to. An example based passed in class may be something this. public interface Processor { public boolean canHandle(Object objectToHandle); public void handle(Object objectToHandle); } public class EvenNumberProcessor extends Processor { public boolean canHandle(Object objectToHandle) { if (!isNumeric(objectToHandle)){ return false } return isEven(objectToHandle); } public void handle(objectToHandle) { //Optionally call canHandleAgain to ensure the calling class is fufilling its contract doSomething(); } } public class OddNumberProcessor extends Processor { public boolean canHandle(Object objectToHandle) { if (!isNumeric(objectToHandle)){ return false } return isOdd(objectToHandle); } public void handle(objectToHandle) { //Optionally call canHandleAgain to ensure the calling class is fufilling its contract doSomething(); } } //Can optionally implement processor interface public class processorDelegator { private List processors; public void addProcessor(Processor processor) { processors.add(processor); } public void process(Object objectToProcess) { //Lookup relevant processor either by keeping a list of what they can process //Or query each one to see if it can process the object. chosenProcessor=chooseProcessor(objectToProcess); chosenProcessor.handle(objectToProcess); } } Note there are a few variations I see on this. In one variation the sub classes provide a list of things they can process which the ProcessorDelegator understands. The other variation which is listed above in fake code is where each is queried in turn. This is similar to chain of command but I don't think its the same as chain of command means that the processor needs to pass to other processors. The other variation is where the ProcessorDelegator itself implements the interface which means you can get trees of ProcessorDelegators which specialise further. In the above example you could have a numeric processor delegator which delegates to an even/odd processor and a string processordelegator which delegates to different strings. My question is does this pattern have a name.

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  • Access functions from user control without events?

    - by BornToCode
    I have an application made with usercontrols and a function on main form that removes the previous user controls and shows the desired usercontrol centered and tweaked: public void DisplayControl(UserControl uControl) I find it much easier to make this function static or access this function by reference from the user control, like this: MainForm mainform_functions = (MainForm)Parent; mainform_functions.DisplayControl(uc_a); You probably think it's a sin to access a function in mainform, from the usercontrol, however, raising an event seems much more complex in such case - I'll give a simple example - let's say I raise an event from usercontrol_A to show usercontrol_B on mainform, so I write this: uc_a.show_uc_b+= (s,e) => { usercontrol_B uc_b = new usercontrol_B(); DisplayControl(uc_b); }; Now what if I want usercontrol_B to also have an event to show usercontrol_C? now it would look like this: uc_a.show_uc_b+= (s,e) => { usercontrol_B uc_b = new usercontrol_B(); DisplayControl(uc_b); uc_b.show_uc_c += (s2,e2) => {usercontrol_C uc_c = new usercontrol_C(); DisplayControl(uc_c);} }; THIS LOOKS AWFUL! The code is much simpler and readable when you actually access the function from the usercontrol itself, therefore I came to the conclusion that in such case it's not so terrible if I break the rules and not use events for such general function, I also think that a readable usercontrol that you need to make small adjustments for another app is preferable than a 100% 'generic' one which makes my code look like a pile of mud. What is your opinion? Am I mistaken?

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  • Confused about javascript module pattern implementation

    - by Damon
    I have a class written on a project I'm working on that I've been told is using the module pattern, but it's doing things a little differently than the examples I've seen. It basically takes this form: (function ($, document, window, undefined) { var module = { foo : bar, aMethod : function (arg) { className.bMethod(arg); }, bMethod : function (arg) { console.log('spoons'); } }; window.ajaxTable = ajaxTable; })(jQuery, document, window); I get what's going on here. But I'm not sure how this relates to most of the definitions I've seen of the module (or revealing?) module pattern. like this one from briancray var module = (function () { // private variables and functions var foo = 'bar'; // constructor var module = function () { }; // prototype module.prototype = { constructor: module, something: function () { } }; // return module return module; })(); var my_module = new module(); Is the first example basically like the second except everything is in the constructor? I'm just wrapping my head around patterns and the little things at the beginnings and endings always make me not sure what I should be doing.

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  • Ideal data structure/techniques for storing generic scheduler data in C#

    - by GraemeMiller
    I am trying to implement a generic scheduler object in C# 4 which will output a table in HTML. Basic aim is to show some object along with various attributes, and whether it was doing something in a given time period. The scheduler will output a table displaying the headers: Detail Field 1 ....N| Date1.........N I want to initialise the table with a start date and an end date to create the date range (ideally could also do other time periods e.g. hours but that isn't vital). I then want to provide a generic object which will have associated events. Where an object has events within the period I want a table cell to be marked E.g. Name Height Weight 1/1/2011 2/1/2011 3/1/20011...... 31/1/2011 Ben 5.11 75 X X X Bill 5.7 83 X X So I created scheduler with Start Date=1/1/2011 and end date 31/1/2011 I'd like to give it my person object (already sorted) and tell it which fields I want displayed (Name, Height, Weight) Each person has events which have a start date and end date. Some events will start and end outwith but they should still be shown on the relevant date etc. Ideally I'd like to have been able to provide it with say a class booking object as well. So I'm trying to keep it generic. I have seen Javasript implementations etc of similar. What would a good data structure be for this? Any thoughts on techniques I could use to make it generic. I am not great with generics so any tips appreciated.

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  • Collision within a poly

    - by G1i1ch
    For an html5 engine I'm making, for speed I'm using a path poly. I'm having trouble trying to find ways to get collision with the walls of the poly. To make it simple I just have a vector for the object and an array of vectors for the poly. I'm using Cartesian vectors and they're 2d. Say poly = [[550,0],[169,523],[-444,323],[-444,-323],[169,-523]], it's just a pentagon I generated. The object that will collide is object, object.pos is it's position and object.vel is it's velocity. They're both 2d vectors too. I've had some success to get it to find a collision, but it's just black box code I ripped from a c++ example. It's very obscure inside and all it does though is return true/false and doesn't return what vertices are collided or collision point, I'd really like to be able to understand this and make my own so I can have more meaningful collision. I'll tackle that later though. Again the question is just how does one find a collision to walls of a poly given you know the poly vertices and the object's position + velocity? If more info is needed please let me know. And if all anyone can do is point me to the right direction that's great.

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  • Abstract Factory Method and Polymorphism

    - by Scotty C.
    Being a PHP programmer for the last couple of years, I'm just starting to get into advanced programming styles and using polymorphic patterns. I was watching a video on polymorphism the other day, and the guy giving the lecture said that if at all possible, you should get rid of if statements in your code, and that a switch is almost always a sign that polymorphism is needed. At this point I was quite inspired and immediately went off to try out these new concepts, so I decided to make a small caching module using a factory method. Of course the very first thing I have to do is create a switch to decide what file encoding to choose. DANG! class Main { public static function methodA($parameter='') { switch ($parameter) { case 'a': $object = new \name\space\object1(); break; case 'b': $object = new \name\space\object2(); break; case 'c': $object = new \name\space\object3(); break; default: $object = new \name\space\object1(); } return (sekretInterface $object); } } At this point I'm not really sure what to do. As far as I can tell, I either have to use a different pattern and have separate methods for each object instance, or accept that a switch is necessary to "switch" between them. What do you guys think?

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  • Flixel: doesn't light tile up

    - by Arno
    i'm creating a game with flixel, and I want to have a effect when you mouse over a tile, I tried implementing it, and this is what it gives: public class GameState extends FlxState { private var block:EmptyBlock; public function GameState() { } override public function create():void { for (var i:Number = 0; i < 30; i++) { block = new EmptyBlock(i, 20); block.create(); } } override public function update():void { block.update(); super.update(); } } } GameState class and here is the EmptyBlock class: public class EmptyBlock { private var x:int; private var y:int; private var row:FlxRect public function EmptyBlock(x:int, y:int ) { this.x = x; this.y = y; } public function create():void { row = new FlxRect(x, y, 32, 32); trace ("Created block at" + x + y); } public function update():void { if (FlxG.mouse.screenX == row.x) { if (FlxG.mouse.screenY == row.y) { var outline:FlxSprite = new FlxSprite(row.x, row.y).makeGraphic(row.width, row.height, 0x002525); } } } } }

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  • 3d Picking under reticle

    - by Wolftousen
    i'm currently trying to work out some 3d picking code that I started years ago, but then lost interested the assignment was completed (this part wasn't actually part of the assignment). I am not using the mouse coords for picking, i'm just using the position in 3d space and a ray directly out from there. A small hitch though is that I want to use a cone and not a ray. Here are the variables i'm using: float iReticleSlope = 95/3000; //inverse reticle slope float baseReticle = 1; //radius of the reticle at z = 0 float maxRange = 3000; //max range to target Quaternion orientation; //the cameras orientation Vector3d position; //the cameras position Then I loop through each object in the world: Vector3d transformed; //object position after transformations float d, r; //holder variables for(i = 0; i < objects.length; i++) { transformed = position - objects[i].position; //transform the position relative to camera orientation.multiply(transformed); //orient the object relative to the camera if(transformed.z < 0) { d = sqrt(transformed[0] * transformed[0] + transformed[1] * transformed[1]); r = -transformed[2] * iReticleSlope + objects[i].radius; if(d < r && -transformed[2] - objects[i].radius <= maxRange) { //the object is under the reticle } else { //the object is not under the reticle } } else { //the object is not under the reticle } } Now this all works fine and dandy until the window ratio doesn't match the resolution ratio. Is there any simple way to account for that

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  • Faster 2D Collision detection

    - by eShredder
    Recently I've been working on a fast-paced 2d shooter and I came across a mighty problem. Collision detection. Sure, it is working, but it is very slow. My goal is: Have lots of enemies on screen and have them to not touch each other. All of the enemies are chasing the player entity. Most of them have the same speed so sooner or later they all end up taking the same space while chasing the player. This really drops the fun factor since, for the player, it looks like you are being chased by one enemy only. To prevent them to take the same space I added a collision detection (a very basic 2D detection, the only method I know of) which is. Enemy class update method Loop through all enemies (continue; if the loop points at this object) If enemy object intersects with this object Push enemy object away from this enemy object This works fine. As long as I only have <200 enemy entities that is. When I get closer to 300-350 enemy entities my frame rate begins to drop heavily. First I thought it was bad rendering so I removed their draw call. This did not help at all so of course I realised it was the update method. The only heavy part in their update method is this each-enemy-loops-through-every-enemy part. When I get closer to 300 enemies the game does a 90000 (300x300) step itteration. My my~ I'm sure there must be another way to aproach this collision detection. Though I have no idea how. The pages I find is about how to actually do the collision between two objects or how to check collision between an object and a tile. I already know those two things. tl;dr? How do I aproach collision detection between LOTS of entities? Quick edit: If it is to any help, I'm using C# XNA.

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  • The idea of functionN in Scala / Functionaljava

    - by Luke Murphy
    From brain driven development It turns out, that every Function you’ll ever define in Scala, will become an instance of an Implementation which will feature a certain Function Trait. There is a whole bunch of that Function Traits, ranging from Function1 up to Function22. Since Functions are Objects in Scala and Scala is a statically typed language, it has to provide an appropriate type for every Function which comes with a different number of arguments. If you define a Function with two arguments, the compiler picks Function2 as the underlying type. Also, from Michael Froh's blog You need to make FunctionN classes for each number of parameters that you want? Yes, but you define the classes once and then you use them forever, or ideally they're already defined in a library (e.g. Functional Java defines classes F, F2, ..., F8, and the Scala standard library defines classes Function1, ..., Function22) So we have a list of function traits (Scala), and a list of interfaces (Functional-java) to enable us to have first class funtions. I am trying to understand exactly why this is the case. I know, in Java for example, when I write a method say, public int add(int a, int b){ return a + b; } That I cannot go ahead and write add(3,4,5); ( error would be something like : method add cannot be applied to give types ) We simply have to define an interface/trait for functions with different parameters, because of static typing?

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  • Basic Mouse Features in Silverlight

    - by Sayre Collado
    Hi Guys, I have basic sample on how to use some features of mouse events in Silverlight. The picture. The Mouse Activity Log is to record the all activity done on the projects. My simple snippets on how to add on the textbox is:         protected void MessageLog(string msg)         {             txtMouseLog.Text += msg;         }   For the Mouse Wheel sample this is the snippets:         private void chkMouseWheel_Checked(object sender, RoutedEventArgs e)         {             image1.MouseWheel += new MouseWheelEventHandler(image1_MouseWheel);         }           void image1_MouseWheel(object sender, MouseWheelEventArgs e)         {             ImgScale.ScaleX = e.Delta > 0 ? ImgScale.ScaleX * 1.5 : ImgScale.ScaleX * 0.8;             ImgScale.ScaleY = e.Delta > 0 ? ImgScale.ScaleY * 1.5 : ImgScale.ScaleY * 0.8;               e.Handled = true;         }    And the XAML:        <Image Height="139" Name="image1" Stretch="Fill" Width="178" Source="/GBLOgs1;component/Images/Sunset.jpg">            <Image.RenderTransform>                 <ScaleTransform x:Name="ImgScale"></ScaleTransform>            </Image.RenderTransform>        </Image     I have also the showing of mouse position:           private void Mouse_MouseMove(object sender, MouseEventArgs e)         {             Point point = e.GetPosition(this);             lblMouseLocation.Content = "X: " + point.X + "and Y: " + point.Y;         }           private void checkBox1_Checked(object sender, RoutedEventArgs e)         {             lblMouseLocation.Visibility = Visibility.Visible;             MessageLog("Mouse Location Visible\n");         }           private void checkBox1_Unchecked(object sender, RoutedEventArgs e)         {             lblMouseLocation.Visibility = Visibility.Collapsed;             MessageLog("Mouse Location Collapsed\n");            And even the counting of clicked event:           int clicked = 0;         private void LayoutRoot_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)         {             Point point = e.GetPosition(this);             clicked++;               string msg = "Mouse Clicked " + clicked.ToString() + " time(s) " +                                     "Mouse Location X and Y: " + point.X + " " + point.Y + "\n";               MessageLog(msg);         }     And now the result of above snippets. Happy Programming.

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  • Persisting simple tree with (Fluent-)NHibernate leads to System.InvalidCastException

    - by fudge
    Hi there, there seems to be a problem with recursive data structures and (Fluent-)NHibernate or its just me, being a complete moron... here's the tree: public class SimpleNode { public SimpleNode () { this.Children = new List<SimpleNode> (); } public virtual SimpleNode Parent { get; private set; } public virtual List<SimpleNode> Children { get; private set; } public virtual void setParent (SimpleNode parent) { parent.AddChild (this); Parent = parent; } public virtual void AddChild (SimpleNode child) { this.Children.Add (child); } public virtual void AddChildren (IEnumerable<SimpleNode> children) { foreach (var child in children) { AddChild (child); } } } the mapping: public class SimpleNodeEntity : ClassMap<SimpleNode> { public SimpleNodeEntity () { Id (x => x.Id); References (x => x.Parent).Nullable (); HasMany (x => x.Children).Not.LazyLoad ().Inverse ().Cascade.All ().KeyNullable (); } } now, whenever I try to save a node, I get this: System.InvalidCastException: Cannot cast from source type to destination type. at (wrapper dynamic-method) SimpleNode. (object,object[],NHibernate.Bytecode.Lightweight.SetterCallback) at NHibernate.Bytecode.Lightweight.AccessOptimizer.SetPropertyValues (object,object[]) at NHibernate.Tuple.Entity.PocoEntityTuplizer.SetPropertyValuesWithOptimizer (object,object[]) My setup: Mono 2.8.1 (on OSX), NHibernate 2.1.2, FluentNHibernate 1.1.0

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  • Acer Aspire One 725 - missing graphic card driver for Radeon HD 6290?

    - by Melon
    Recently I bought an Acer Aspire One 725 Netbook and installed Ubuntu 12.10 on it. I bought it, because it can run HD movies and has Full HD on external VGA port. However, movies from youtube have a really slow framerate. If you open three tabs in Opera (for example g-mail, youtube and askubuntu) it gets really laggy. My suspicion is that the driver for graphic card is missing. When I check the System->Details->Graphics the driver is unknown. After running lspci | grep VGA I get this output: 00:01.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Device 980a From what I see, I have a AMD C70 processor integrated with (or something similar) AMD Radeon HD 6290. Has anyone had the same problem? Do you know which drivers need to be installed for the graphics to work properly? On official Acer page there are only drivers for Win7 and Win8... Update: I have tried installing fglrx but I get the following error (either I don't have libraries or someone didn't make a clean build before release ;) /lib/modules/fglrx/build_mod/2.6.x/firegl_public.c: In function ‘KCL_MEM_AllocLinearAddrInterval’: /lib/modules/fglrx/build_mod/2.6.x/firegl_public.c:2124:5: error: implicit declaration of function ‘do_mmap’ [-Werror=implicit-function-declaration] /lib/modules/fglrx/build_mod/2.6.x/firegl_public.c:2124:13: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast] /lib/modules/fglrx/build_mod/2.6.x/firegl_public.c: In function ‘kasInitExecutionLevels’: /lib/modules/fglrx/build_mod/2.6.x/firegl_public.c:4159:5: error: ‘cpu_possible_map’ undeclared (first use in this function) /lib/modules/fglrx/build_mod/2.6.x/firegl_public.c:4159:5: note: each undeclared identifier is reported only once for each function it appears in /lib/modules/fglrx/build_mod/2.6.x/firegl_public.c:4159:5: warning: left-hand operand of comma expression has no effect [-Wunused-value] Update 2: After fixing the erros in compilation, ubuntu acts bizarre and unstable (no left icon panel, no upper panel, cannot run any programs, I only see desktop)

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  • Repository query conditions, dependencies and DRY

    - by vFragosop
    To keep it simple, let's suppose an application which has Accounts and Users. Each account may have any number of users. There's also 3 consumers of UserRepository: An admin interface which may list all users Public front-end which may list all users An account authenticated API which should only list it's own users Assuming UserRepository is something like this: class UsersRepository extends DatabaseAbstraction { private function query() { return $this->database()->select('users.*'); } public function getAll() { return $this->query()->exec(); } // IMPORTANT: // Tons of other methods for searching, filtering, // joining of other tables, ordering and such... } Keeping in mind the comment above, and the necessity to abstract user querying conditions, How should I handle querying of users filtering by account_id? I can picture three possible roads: 1. Should I create an AccountUsersRepository? class AccountUsersRepository extends UserRepository { public function __construct(Account $account) { $this->account = $account; } private function query() { return parent::query() ->where('account_id', '=', $this->account->id); } } This has the advantage of reducing the duplication of UsersRepository methods, but doesn't quite fit into anything I've read about DDD so far (I'm rookie by the way) 2. Should I put it as a method on AccountsRepository? class AccountsRepository extends DatabaseAbstraction { public function getAccountUsers(Account $account) { return $this->database() ->select('users.*') ->where('account_id', '=', $account->id) ->exec(); } } This requires the duplication of all UserRepository methods and may need another UserQuery layer, that implements those querying logic on chainable way. 3. Should I query UserRepository from within my account entity? class Account extends Entity { public function getUsers() { return UserRepository::findByAccountId($this->id); } } This feels more like an aggregate root for me, but introduces dependency of UserRepository on Account entity, which may violate a few principles. 4. Or am I missing the point completely? Maybe there's an even better solution? Footnotes: Besides permissions being a Service concern, in my understanding, they shouldn't implement SQL query but leave that to repositories since those may not even be SQL driven.

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  • multi-thread in mmorpg server

    - by jean
    For MMORPG, there is a tick function to update every object's state in a map. The function was triggered by a timer in fixed interval. So each map's update can be dispatch to different thread. At other side, server handle player incoming package have its own threads also: I/O threads. Generally, the handler of the corresponding incoming package run in I/O threads. So there is a problem: thread synchronization. I have consider two methods: Synchronize with mutex. I/O thread lock a mutex before execute handler function and map thread lock same mutex before it execute map's update. Execute all handler functions in map's thread, I/O thread only queue the incoming handler and let map thread to pop the queue then call handler function. These two have a disadvantage: delay. For method 1, if the map's tick function is running, then all clients' request need to waiting the lock release. For method 2, if map's tick function is running, all clients' request need to waiting for next tick to be handle. Of course, there is another method: add lock to functions that use data which will be accessed both in I/O thread & map thread. But this is hard to maintain and easy to goes incorrect. It needs carefully check all variables whether or not accessed by both two kinds thread. My problem is: is there better way to do this? Notice that I said map is logic concept means no interactions can happen between two map except transport. I/O thread means thread in 3rd part network lib which used to handle client request.

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  • How best to construct our test subjects in unit tests?

    - by Liath
    Some of our business logic classes require quite a few dependencies (in our case 7-10). As such when we come to unit test these the creation become quite complex. In most tests these dependencies are often not required (only some dependencies are required for particular methods). As a result unit tests often require a significant number of lines of code to mock up these useless dependencies (which can't be null because of null checks). For example: [Test] public void TestMethodA() { var dependency5 = new Mock<IDependency1>(); dependency5.Setup(x => x. // some setup var sut = new Sut(new Mock<IDependency1>().Object, new Mock<IDependency2>().Object, new Mock<IDependency3>().Object, new Mock<IDependency4>().Object, dependency5); Assert.SomeAssert(sut.MethodA()); } In this example almost half the test is taken up creating dependencies which aren't used. I've investigated an approach where I have a helper method. [Test] public void TestMethodA() { var dependency5 = new Mock<IDependency1>(); dependency5.Setup(x => x. // some setup var sut = CreateSut(null, null, null, null, dependency5); Assert.SomeAssert(sut.MethodA()); } private Sut CreateSut(IDependency1 d1, IDependency2 d2...) { return new Sut(d1 ?? new Mock<IDependency1>().Object, d2 ?? new Mock<IDependency2>().Object, } But these often grow very complicated very quickly. What is the best way to create these BLL classes in test classes to reduce complexity and simplify tests?

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  • Java Program help [migrated]

    - by georgetheevilman
    Okay I have a really annoying error. Its coming from my retainAll method. The problem is that I am outputting 1,3,5 in ints at the end, but I need 1,3,5,7,9. Here is the code below for the MySet and driver classes public class MySetTester { public static void main(String[]args) { MySet<String> strings = new MySet<String>(); strings.add("Hey!"); strings.add("Hey!"); strings.add("Hey!"); strings.add("Hey!"); strings.add("Hey!"); strings.add("Listen!"); strings.add("Listen!"); strings.add("Sorry, I couldn't resist."); strings.add("Sorry, I couldn't resist."); strings.add("(you know you would if you could)"); System.out.println("Testing add:\n"); System.out.println("Your size: " + strings.size() + ", contains(Sorry): " + strings.contains("Sorry, I couldn't resist.")); System.out.println("Exp. size: 4, contains(Sorry): true\n"); MySet<String> moreStrings = new MySet<String>(); moreStrings.add("Sorry, I couldn't resist."); moreStrings.add("(you know you would if you could)"); strings.removeAll(moreStrings); System.out.println("Testing remove and removeAll:\n"); System.out.println("Your size: " + strings.size() + ", contains(Sorry): " + strings.contains("Sorry, I couldn't resist.")); System.out.println("Exp. size: 2, contains(Sorry): false\n"); MySet<Integer> ints = new MySet<Integer>(); for (int i = 0; i < 100; i++) { ints.add(i); } System.out.println("Your size: " + ints.size()); System.out.println("Exp. size: 100\n"); for (int i = 0; i < 100; i += 2) { ints.remove(i); } System.out.println("Your size: " + ints.size()); System.out.println("Exp. size: 50\n"); MySet<Integer> zeroThroughNine = new MySet<Integer>(); for (int i = 0; i < 10; i++) { zeroThroughNine.add(i); } ints.retainAll(zeroThroughNine); System.out.println("ints should now only retain odd numbers" + " 0 through 10\n"); System.out.println("Testing your iterator:\n"); for (Integer i : ints) { System.out.println(i); } System.out.println("\nExpected: \n\n1 \n3 \n5 \n7 \n9\n"); System.out.println("Yours:"); for (String s : strings) { System.out.println(s); } System.out.println("\nExpected: \nHey! \nListen!"); strings.clear(); System.out.println("\nClearing your set...\n"); System.out.println("Your set is empty: " + strings.isEmpty()); System.out.println("Exp. set is empty: true"); } } And here is the main code. But still read the top part because that's where my examples are. import java.util.Set; import java.util.Collection; import java.lang.Iterable; import java.util.Iterator; import java.util.Arrays; import java.lang.reflect.Array; public class MySet implements Set, Iterable { // instance variables - replace the example below with your own private E[] backingArray; private int numElements; /** * Constructor for objects of class MySet */ public MySet() { backingArray=(E[]) new Object[5]; numElements=0; } public boolean add(E e){ for(Object elem:backingArray){ if (elem==null ? e==null : elem.equals(e)){ return false; } } if(numElements==backingArray.length){ E[] newArray=Arrays.copyOf(backingArray,backingArray.length*2); newArray[numElements]=e; numElements=numElements+1; backingArray=newArray; return true; } else{ backingArray[numElements]=e; numElements=numElements+1; return true; } } public boolean addAll(Collection<? extends E> c){ for(E elem:c){ this.add(elem); } return true; } public void clear(){ E[] newArray=(E[])new Object[backingArray.length]; numElements=0; backingArray=newArray; } public boolean equals(Object o){ if(o instanceof Set &&(((Set)o).size()==numElements)){ for(E elem:(Set<E>)o){ if (this.contains(o)==false){ return false; } return true; } } return false; } public boolean contains(Object o){ for(E backingElem:backingArray){ if (o!=null && o.equals(backingElem)){ return true; } } return false; } public boolean containsAll(Collection<?> c){ for(E elem:(Set<E>)c){ if(!(this.contains(elem))){ return false; } } return true; } public int hashCode(){ int sum=0; for(E elem:backingArray){ if(elem!=null){ sum=sum+elem.hashCode(); } } return sum; } public boolean isEmpty(){ if(numElements==0){ return true; } else{ return false; } } public boolean remove(Object o){ int i=0; for(Object elem:backingArray){ if(o!=null && o.equals(elem)){ backingArray[i]=null; numElements=numElements-1; E[] newArray=Arrays.copyOf(backingArray,backingArray.length-1); return true; } i=i+1; } return false; } public boolean removeAll(Collection<?> c){ for(Object elem:c){ this.remove(elem); } return true; } public boolean retainAll(Collection<?> c){ MySet<E> removalArray=new MySet<E>(); for(E arrayElem:backingArray){ if(arrayElem!= null && !(c.contains(arrayElem))){ this.remove(arrayElem); } } return false; } public int size(){ return numElements; } public <T> T[] toArray(T[] a) throws ArrayStoreException,NullPointerException{ for(int i=0;i<numElements;i++){ a[i]=(T)backingArray[i]; } for(int j=numElements;j<a.length;j++){ a[j]=null; } return a; } public Object[] toArray(){ Object[] newArray=new Object[numElements]; for(int i=0;i<numElements;i++){ newArray[i]=backingArray[i]; } return newArray; } public Iterator<E> iterator(){ setIterator iterator=new setIterator(); return iterator; } private class setIterator implements Iterator<E>{ private int currIndex; private E lastElement; public setIterator(){ currIndex=0; lastElement=null; } public boolean hasNext(){ while(currIndex<=numElements && backingArray[currIndex]==null){ currIndex=currIndex+1; } if (currIndex<=numElements){ return true; } return false; } public E next(){ E element=backingArray[currIndex]; currIndex=currIndex+1; lastElement=element; return element; } public void remove() throws UnsupportedOperationException,IllegalStateException{ if(lastElement!=null){ MySet.this.remove((Object)lastElement); numElements=numElements-1; } else{ throw new IllegalStateException(); } } } } I've been able to reduce the problems, but otherwise this thing is still causing problems.

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  • What are good design practices when working with Entity Framework

    - by AD
    This will apply mostly for an asp.net application where the data is not accessed via soa. Meaning that you get access to the objects loaded from the framework, not Transfer Objects, although some recommendation still apply. This is a community post, so please add to it as you see fit. Applies to: Entity Framework 1.0 shipped with Visual Studio 2008 sp1. Why pick EF in the first place? Considering it is a young technology with plenty of problems (see below), it may be a hard sell to get on the EF bandwagon for your project. However, it is the technology Microsoft is pushing (at the expense of Linq2Sql, which is a subset of EF). In addition, you may not be satisfied with NHibernate or other solutions out there. Whatever the reasons, there are people out there (including me) working with EF and life is not bad.make you think. EF and inheritance The first big subject is inheritance. EF does support mapping for inherited classes that are persisted in 2 ways: table per class and table the hierarchy. The modeling is easy and there are no programming issues with that part. (The following applies to table per class model as I don't have experience with table per hierarchy, which is, anyway, limited.) The real problem comes when you are trying to run queries that include one or many objects that are part of an inheritance tree: the generated sql is incredibly awful, takes a long time to get parsed by the EF and takes a long time to execute as well. This is a real show stopper. Enough that EF should probably not be used with inheritance or as little as possible. Here is an example of how bad it was. My EF model had ~30 classes, ~10 of which were part of an inheritance tree. On running a query to get one item from the Base class, something as simple as Base.Get(id), the generated SQL was over 50,000 characters. Then when you are trying to return some Associations, it degenerates even more, going as far as throwing SQL exceptions about not being able to query more than 256 tables at once. Ok, this is bad, EF concept is to allow you to create your object structure without (or with as little as possible) consideration on the actual database implementation of your table. It completely fails at this. So, recommendations? Avoid inheritance if you can, the performance will be so much better. Use it sparingly where you have to. In my opinion, this makes EF a glorified sql-generation tool for querying, but there are still advantages to using it. And ways to implement mechanism that are similar to inheritance. Bypassing inheritance with Interfaces First thing to know with trying to get some kind of inheritance going with EF is that you cannot assign a non-EF-modeled class a base class. Don't even try it, it will get overwritten by the modeler. So what to do? You can use interfaces to enforce that classes implement some functionality. For example here is a IEntity interface that allow you to define Associations between EF entities where you don't know at design time what the type of the entity would be. public enum EntityTypes{ Unknown = -1, Dog = 0, Cat } public interface IEntity { int EntityID { get; } string Name { get; } Type EntityType { get; } } public partial class Dog : IEntity { // implement EntityID and Name which could actually be fields // from your EF model Type EntityType{ get{ return EntityTypes.Dog; } } } Using this IEntity, you can then work with undefined associations in other classes // lets take a class that you defined in your model. // that class has a mapping to the columns: PetID, PetType public partial class Person { public IEntity GetPet() { return IEntityController.Get(PetID,PetType); } } which makes use of some extension functions: public class IEntityController { static public IEntity Get(int id, EntityTypes type) { switch (type) { case EntityTypes.Dog: return Dog.Get(id); case EntityTypes.Cat: return Cat.Get(id); default: throw new Exception("Invalid EntityType"); } } } Not as neat as having plain inheritance, particularly considering you have to store the PetType in an extra database field, but considering the performance gains, I would not look back. It also cannot model one-to-many, many-to-many relationship, but with creative uses of 'Union' it could be made to work. Finally, it creates the side effet of loading data in a property/function of the object, which you need to be careful about. Using a clear naming convention like GetXYZ() helps in that regards. Compiled Queries Entity Framework performance is not as good as direct database access with ADO (obviously) or Linq2SQL. There are ways to improve it however, one of which is compiling your queries. The performance of a compiled query is similar to Linq2Sql. What is a compiled query? It is simply a query for which you tell the framework to keep the parsed tree in memory so it doesn't need to be regenerated the next time you run it. So the next run, you will save the time it takes to parse the tree. Do not discount that as it is a very costly operation that gets even worse with more complex queries. There are 2 ways to compile a query: creating an ObjectQuery with EntitySQL and using CompiledQuery.Compile() function. (Note that by using an EntityDataSource in your page, you will in fact be using ObjectQuery with EntitySQL, so that gets compiled and cached). An aside here in case you don't know what EntitySQL is. It is a string-based way of writing queries against the EF. Here is an example: "select value dog from Entities.DogSet as dog where dog.ID = @ID". The syntax is pretty similar to SQL syntax. You can also do pretty complex object manipulation, which is well explained [here][1]. Ok, so here is how to do it using ObjectQuery< string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); The first time you run this query, the framework will generate the expression tree and keep it in memory. So the next time it gets executed, you will save on that costly step. In that example EnablePlanCaching = true, which is unnecessary since that is the default option. The other way to compile a query for later use is the CompiledQuery.Compile method. This uses a delegate: static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => ctx.DogSet.FirstOrDefault(it => it.ID == id)); or using linq static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet where dog.ID == id select dog).FirstOrDefault()); to call the query: query_GetDog.Invoke( YourContext, id ); The advantage of CompiledQuery is that the syntax of your query is checked at compile time, where as EntitySQL is not. However, there are other consideration... Includes Lets say you want to have the data for the dog owner to be returned by the query to avoid making 2 calls to the database. Easy to do, right? EntitySQL string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)).Include("Owner"); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); CompiledQuery static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet.Include("Owner") where dog.ID == id select dog).FirstOrDefault()); Now, what if you want to have the Include parametrized? What I mean is that you want to have a single Get() function that is called from different pages that care about different relationships for the dog. One cares about the Owner, another about his FavoriteFood, another about his FavotireToy and so on. Basicly, you want to tell the query which associations to load. It is easy to do with EntitySQL public Dog Get(int id, string include) { string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)) .IncludeMany(include); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); } The include simply uses the passed string. Easy enough. Note that it is possible to improve on the Include(string) function (that accepts only a single path) with an IncludeMany(string) that will let you pass a string of comma-separated associations to load. Look further in the extension section for this function. If we try to do it with CompiledQuery however, we run into numerous problems: The obvious static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.Include(include) where dog.ID == id select dog).FirstOrDefault()); will choke when called with: query_GetDog.Invoke( YourContext, id, "Owner,FavoriteFood" ); Because, as mentionned above, Include() only wants to see a single path in the string and here we are giving it 2: "Owner" and "FavoriteFood" (which is not to be confused with "Owner.FavoriteFood"!). Then, let's use IncludeMany(), which is an extension function static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.IncludeMany(include) where dog.ID == id select dog).FirstOrDefault()); Wrong again, this time it is because the EF cannot parse IncludeMany because it is not part of the functions that is recognizes: it is an extension. Ok, so you want to pass an arbitrary number of paths to your function and Includes() only takes a single one. What to do? You could decide that you will never ever need more than, say 20 Includes, and pass each separated strings in a struct to CompiledQuery. But now the query looks like this: from dog in ctx.DogSet.Include(include1).Include(include2).Include(include3) .Include(include4).Include(include5).Include(include6) .[...].Include(include19).Include(include20) where dog.ID == id select dog which is awful as well. Ok, then, but wait a minute. Can't we return an ObjectQuery< with CompiledQuery? Then set the includes on that? Well, that what I would have thought so as well: static readonly Func<Entities, int, ObjectQuery<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, ObjectQuery<Dog>>((ctx, id) => (ObjectQuery<Dog>)(from dog in ctx.DogSet where dog.ID == id select dog)); public Dog GetDog( int id, string include ) { ObjectQuery<Dog> oQuery = query_GetDog(id); oQuery = oQuery.IncludeMany(include); return oQuery.FirstOrDefault; } That should have worked, except that when you call IncludeMany (or Include, Where, OrderBy...) you invalidate the cached compiled query because it is an entirely new one now! So, the expression tree needs to be reparsed and you get that performance hit again. So what is the solution? You simply cannot use CompiledQueries with parametrized Includes. Use EntitySQL instead. This doesn't mean that there aren't uses for CompiledQueries. It is great for localized queries that will always be called in the same context. Ideally CompiledQuery should always be used because the syntax is checked at compile time, but due to limitation, that's not possible. An example of use would be: you may want to have a page that queries which two dogs have the same favorite food, which is a bit narrow for a BusinessLayer function, so you put it in your page and know exactly what type of includes are required. Passing more than 3 parameters to a CompiledQuery Func is limited to 5 parameters, of which the last one is the return type and the first one is your Entities object from the model. So that leaves you with 3 parameters. A pitance, but it can be improved on very easily. public struct MyParams { public string param1; public int param2; public DateTime param3; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where dog.Age == myParams.param2 && dog.Name == myParams.param1 and dog.BirthDate > myParams.param3 select dog); public List<Dog> GetSomeDogs( int age, string Name, DateTime birthDate ) { MyParams myParams = new MyParams(); myParams.param1 = name; myParams.param2 = age; myParams.param3 = birthDate; return query_GetDog(YourContext,myParams).ToList(); } Return Types (this does not apply to EntitySQL queries as they aren't compiled at the same time during execution as the CompiledQuery method) Working with Linq, you usually don't force the execution of the query until the very last moment, in case some other functions downstream wants to change the query in some way: static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public IEnumerable<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name); } public void DataBindStuff() { IEnumerable<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } What is going to happen here? By still playing with the original ObjectQuery (that is the actual return type of the Linq statement, which implements IEnumerable), it will invalidate the compiled query and be force to re-parse. So, the rule of thumb is to return a List< of objects instead. static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public List<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name).ToList(); //<== change here } public void DataBindStuff() { List<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } When you call ToList(), the query gets executed as per the compiled query and then, later, the OrderBy is executed against the objects in memory. It may be a little bit slower, but I'm not even sure. One sure thing is that you have no worries about mis-handling the ObjectQuery and invalidating the compiled query plan. Once again, that is not a blanket statement. ToList() is a defensive programming trick, but if you have a valid reason not to use ToList(), go ahead. There are many cases in which you would want to refine the query before executing it. Performance What is the performance impact of compiling a query? It can actually be fairly large. A rule of thumb is that compiling and caching the query for reuse takes at least double the time of simply executing it without caching. For complex queries (read inherirante), I have seen upwards to 10 seconds. So, the first time a pre-compiled query gets called, you get a performance hit. After that first hit, performance is noticeably better than the same non-pre-compiled query. Practically the same as Linq2Sql When you load a page with pre-compiled queries the first time you will get a hit. It will load in maybe 5-15 seconds (obviously more than one pre-compiled queries will end up being called), while subsequent loads will take less than 300ms. Dramatic difference, and it is up to you to decide if it is ok for your first user to take a hit or you want a script to call your pages to force a compilation of the queries. Can this query be cached? { Dog dog = from dog in YourContext.DogSet where dog.ID == id select dog; } No, ad-hoc Linq queries are not cached and you will incur the cost of generating the tree every single time you call it. Parametrized Queries Most search capabilities involve heavily parametrized queries. There are even libraries available that will let you build a parametrized query out of lamba expressions. The problem is that you cannot use pre-compiled queries with those. One way around that is to map out all the possible criteria in the query and flag which one you want to use: public struct MyParams { public string name; public bool checkName; public int age; public bool checkAge; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where (myParams.checkAge == true && dog.Age == myParams.age) && (myParams.checkName == true && dog.Name == myParams.name ) select dog); protected List<Dog> GetSomeDogs() { MyParams myParams = new MyParams(); myParams.name = "Bud"; myParams.checkName = true; myParams.age = 0; myParams.checkAge = false; return query_GetDog(YourContext,myParams).ToList(); } The advantage here is that you get all the benifits of a pre-compiled quert. The disadvantages are that you most likely will end up with a where clause that is pretty difficult to maintain, that you will incur a bigger penalty for pre-compiling the query and that each query you run is not as efficient as it could be (particularly with joins thrown in). Another way is to build an EntitySQL query piece by piece, like we all did with SQL. protected List<Dod> GetSomeDogs( string name, int age) { string query = "select value dog from Entities.DogSet where 1 = 1 "; if( !String.IsNullOrEmpty(name) ) query = query + " and dog.Name == @Name "; if( age > 0 ) query = query + " and dog.Age == @Age "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); if( !String.IsNullOrEmpty(name) ) oQuery.Parameters.Add( new ObjectParameter( "Name", name ) ); if( age > 0 ) oQuery.Parameters.Add( new ObjectParameter( "Age", age ) ); return oQuery.ToList(); } Here the problems are: - there is no syntax checking during compilation - each different combination of parameters generate a different query which will need to be pre-compiled when it is first run. In this case, there are only 4 different possible queries (no params, age-only, name-only and both params), but you can see that there can be way more with a normal world search. - Noone likes to concatenate strings! Another option is to query a large subset of the data and then narrow it down in memory. This is particularly useful if you are working with a definite subset of the data, like all the dogs in a city. You know there are a lot but you also know there aren't that many... so your CityDog search page can load all the dogs for the city in memory, which is a single pre-compiled query and then refine the results protected List<Dod> GetSomeDogs( string name, int age, string city) { string query = "select value dog from Entities.DogSet where dog.Owner.Address.City == @City "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); oQuery.Parameters.Add( new ObjectParameter( "City", city ) ); List<Dog> dogs = oQuery.ToList(); if( !String.IsNullOrEmpty(name) ) dogs = dogs.Where( it => it.Name == name ); if( age > 0 ) dogs = dogs.Where( it => it.Age == age ); return dogs; } It is particularly useful when you start displaying all the data then allow for filtering. Problems: - Could lead to serious data transfer if you are not careful about your subset. - You can only filter on the data that you returned. It means that if you don't return the Dog.Owner association, you will not be able to filter on the Dog.Owner.Name So what is the best solution? There isn't any. You need to pick the solution that works best for you and your problem: - Use lambda-based query building when you don't care about pre-compiling your queries. - Use fully-defined pre-compiled Linq query when your object structure is not too complex. - Use EntitySQL/string concatenation when the structure could be complex and when the possible number of different resulting queries are small (which means fewer pre-compilation hits). - Use in-memory filtering when you are working with a smallish subset of the data or when you had to fetch all of the data on the data at first anyway (if the performance is fine with all the data, then filtering in memory will not cause any time to be spent in the db). Singleton access The best way to deal with your context and entities accross all your pages is to use the singleton pattern: public sealed class YourContext { private const string instanceKey = "On3GoModelKey"; YourContext(){} public static YourEntities Instance { get { HttpContext context = HttpContext.Current; if( context == null ) return Nested.instance; if (context.Items[instanceKey] == null) { On3GoEntities entity = new On3GoEntities(); context.Items[instanceKey] = entity; } return (YourEntities)context.Items[instanceKey]; } } class Nested { // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit static Nested() { } internal static readonly YourEntities instance = new YourEntities(); } } NoTracking, is it worth it? When executing a query, you can tell the framework to track the objects it will return or not. What does it mean? With tracking enabled (the default option), the framework will track what is going on with the object (has it been modified? Created? Deleted?) and will also link objects together, when further queries are made from the database, which is what is of interest here. For example, lets assume that Dog with ID == 2 has an owner which ID == 10. Dog dog = (from dog in YourContext.DogSet where dog.ID == 2 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Person owner = (from o in YourContext.PersonSet where o.ID == 10 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == true; If we were to do the same with no tracking, the result would be different. ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog = oDogQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>) (from o in YourContext.PersonSet where o.ID == 10 select o); oPersonQuery.MergeOption = MergeOption.NoTracking; Owner owner = oPersonQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Tracking is very useful and in a perfect world without performance issue, it would always be on. But in this world, there is a price for it, in terms of performance. So, should you use NoTracking to speed things up? It depends on what you are planning to use the data for. Is there any chance that the data your query with NoTracking can be used to make update/insert/delete in the database? If so, don't use NoTracking because associations are not tracked and will causes exceptions to be thrown. In a page where there are absolutly no updates to the database, you can use NoTracking. Mixing tracking and NoTracking is possible, but it requires you to be extra careful with updates/inserts/deletes. The problem is that if you mix then you risk having the framework trying to Attach() a NoTracking object to the context where another copy of the same object exist with tracking on. Basicly, what I am saying is that Dog dog1 = (from dog in YourContext.DogSet where dog.ID == 2).FirstOrDefault(); ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog2 = oDogQuery.FirstOrDefault(); dog1 and dog2 are 2 different objects, one tracked and one not. Using the detached object in an update/insert will force an Attach() that will say "Wait a minute, I do already have an object here with the same database key. Fail". And when you Attach() one object, all of its hierarchy gets attached as well, causing problems everywhere. Be extra careful. How much faster is it with NoTracking It depends on the queries. Some are much more succeptible to tracking than other. I don't have a fast an easy rule for it, but it helps. So I should use NoTracking everywhere then? Not exactly. There are some advantages to tracking object. The first one is that the object is cached, so subsequent call for that object will not hit the database. That cache is only valid for the lifetime of the YourEntities object, which, if you use the singleton code above, is the same as the page lifetime. One page request == one YourEntity object. So for multiple calls for the same object, it will load only once per page request. (Other caching mechanism could extend that). What happens when you are using NoTracking and try to load the same object multiple times? The database will be queried each time, so there is an impact there. How often do/should you call for the same object during a single page request? As little as possible of course, but it does happens. Also remember the piece above about having the associations connected automatically for your? You don't have that with NoTracking, so if you load your data in multiple batches, you will not have a link to between them: ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>)(from dog in YourContext.DogSet select dog); oDogQuery.MergeOption = MergeOption.NoTracking; List<Dog> dogs = oDogQuery.ToList(); ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>)(from o in YourContext.PersonSet select o); oPersonQuery.MergeOption = MergeOption.NoTracking; List<Person> owners = oPersonQuery.ToList(); In this case, no dog will have its .Owner property set. Some things to keep in mind when you are trying to optimize the performance. No lazy loading, what am I to do? This can be seen as a blessing in disguise. Of course it is annoying to load everything manually. However, it decreases the number of calls to the db and forces you to think about when you should load data. The more you can load in one database call the better. That was always true, but it is enforced now with this 'feature' of EF. Of course, you can call if( !ObjectReference.IsLoaded ) ObjectReference.Load(); if you want to, but a better practice is to force the framework to load the objects you know you will need in one shot. This is where the discussion about parametrized Includes begins to make sense. Lets say you have you Dog object public class Dog { public Dog Get(int id) { return YourContext.DogSet.FirstOrDefault(it => it.ID == id ); } } This is the type of function you work with all the time. It gets called from all over the place and once you have that Dog object, you will do very different things to it in different functions. First, it should be pre-compiled, because you will call that very often. Second, each different pages will want to have access to a different subset of the Dog data. Some will want the Owner, some the FavoriteToy, etc. Of course, you could call Load() for each reference you need anytime you need one. But that will generate a call to the database each time. Bad idea. So instead, each page will ask for the data it wants to see when it first request for the Dog object: static public Dog Get(int id) { return GetDog(entity,"");} static public Dog Get(int id, string includePath) { string query = "select value o " + " from YourEntities.DogSet as o " +

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  • Data from 6 ArrayLists into a single JTable - Java Swing

    - by Splunk
    I have created a JTable which is populated by various arraylists which get their data from a text list using a "~" to split. The issue I am having is that the table is displaying all data from the list on a single row. For example: Column1 Column2 Column2 Column2 Column3 Column4 1,2,3,4,5 1,2,3,4,5 1,2,3,4,5 1,2,3,4,5 1,2,3,4,5 1,2,3,4,5 When I want it to display Column1 Column2 Column2 Column2 Column3 Column4 1 1 1 1 1 1 2 2 2 2 2 2 3 3 3 3 3 3 You get the idea. From previous advice, I think the issue may be looping, but I am not sure. Any advice would be great. The code is below: private void table(){ String[] colName = { "Course", "Examiner", "Moderator", "Semester Available ", "Associated Programs", "Associated Majors"}; DefaultTableModel model = new DefaultTableModel(colName,0); for(Object item : courseList){ Object[] row = new Object[6]; // String[] row = new String[6]; row[0] = fileManage.getCourseList(); row[1] = fileManage.getNameList(); row[2] = fileManage.getModeratorList(); row[3] = fileManage.getSemesterList(); row[4] = fileManage.getProgramList(); row[5] = fileManage.getMajorList(); model.addRow(row); textArea = new JTable(model); } This is the class that has the arraylists: import java.io.File; import java.io.FileNotFoundException; import java.util.ArrayList; import java.util.Collections; import java.util.HashSet; import java.util.Scanner; public class FileIOManagement { private ArrayList<String> nameList = new ArrayList<String>(); private ArrayList<String> courseList = new ArrayList<String>(); private ArrayList<String> semesterList = new ArrayList<String>(); private ArrayList<String> moderatorList = new ArrayList<String>(); private ArrayList<String> programList = new ArrayList<String>(); private ArrayList<String> majorList = new ArrayList<String>(); public ArrayList<String> getNameList(){ return this.nameList; } public ArrayList<String> getCourseList(){ return this.courseList; } public ArrayList<String> getSemesterList(){ return this.semesterList; } public ArrayList<String> getModeratorList(){ return this.moderatorList; } public ArrayList<String> getProgramList(){ return this.programList; } public ArrayList<String> getMajorList(){ return this.majorList; } public void setNameList(ArrayList<String> nameList){ this.nameList = nameList; } public void setCourseList(ArrayList<String> courseList){ this.courseList = courseList; } public void setSemesterList(ArrayList<String> semesterList){ this.semesterList = semesterList; } public void setModeratorList(ArrayList<String> moderatorList){ this.moderatorList = moderatorList; } public void setProgramList(ArrayList<String> programList){ this.programList = programList; } public void setMajorList(ArrayList<String> majorList){ this.majorList = majorList; } public FileIOManagement(){ setNameList(new ArrayList<String>()); setCourseList(new ArrayList<String>()); setSemesterList(new ArrayList<String>()); setModeratorList(new ArrayList<String>()); setProgramList(new ArrayList<String>()); setMajorList(new ArrayList<String>()); readTextFile(); getNameList(); getCourseList(); } private void readTextFile(){ try{ Scanner scan = new Scanner(new File("Course.txt")); while(scan.hasNextLine()){ String line = scan.nextLine(); String[] tokens = line.split("~"); String course = tokens[0].trim(); String examiner = tokens[1].trim(); String moderator = tokens[2].trim(); String semester = tokens[3].trim(); String program = tokens[4].trim(); String major = tokens[5].trim(); courseList.add(course); semesterList.add(semester); nameList.add(examiner); moderatorList.add(moderator); programList.add(program); majorList.add(major); HashSet hs = new HashSet(); hs.addAll(nameList); nameList.clear(); nameList.addAll(hs); Collections.sort(nameList); } scan.close(); } catch (FileNotFoundException e){ e.printStackTrace(); } } } This is the class where I need to have the JTable: import java.awt.*; import javax.swing.*; import java.io.*; import javax.swing.border.EmptyBorder; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.util.ArrayList; import javax.swing.table.DefaultTableModel; public class AllDataGUI extends JFrame{ private JButton saveCloseBtn = new JButton("Save Changes and Close"); private JButton closeButton = new JButton("Exit Without Saving"); private JFrame frame=new JFrame("Viewing All Program Details"); private final FileIOManagement fileManage = new FileIOManagement(); private ArrayList<String> nameList = new ArrayList(); private ArrayList<String> courseList = new ArrayList(); private ArrayList<String> semesterList = new ArrayList(); private ArrayList<String> moderatorList = new ArrayList(); private ArrayList<String> majorList = new ArrayList(); private ArrayList<String> programList = new ArrayList(); private JTable textArea; public ArrayList<String> getNameList(){ return this.nameList; } public ArrayList<String> getCourseList(){ return this.courseList; } public ArrayList<String> getSemesterList(){ return this.semesterList; } public ArrayList<String> getModeratorList(){ return this.moderatorList; } public ArrayList<String> getProgramList(){ return this.programList; } public ArrayList<String> getMajorList(){ return this.majorList; } public void setNameList(ArrayList<String> nameList){ this.nameList = nameList; } public void setCourseList(ArrayList<String> courseList){ this.courseList = courseList; } public void setSemesterList(ArrayList<String> semesterList){ this.semesterList = semesterList; } public void setModeratorList(ArrayList<String> moderatorList){ this.moderatorList = moderatorList; } public void setProgramList(ArrayList<String> programList){ this.programList = programList; } public void setMajorList(ArrayList<String> majorList){ this.majorList = majorList; } public AllDataGUI(){ getData(); table(); panels(); } public Object getValueAt(int rowIndex, int columnIndex) { String[] token = nameList.get(rowIndex).split(","); return token[columnIndex]; } private void table(){ String[] colName = { "Course", "Examiner", "Moderator", "Semester Available ", "Associated Programs", "Associated Majors"}; DefaultTableModel model = new DefaultTableModel(colName,0); for(Object item : courseList){ Object[] row = new Object[6]; // String[] row = new String[6]; row[0] = fileManage.getCourseList(); row[1] = fileManage.getNameList(); row[2] = fileManage.getModeratorList(); row[3] = fileManage.getSemesterList(); row[4] = fileManage.getProgramList(); row[5] = fileManage.getMajorList(); model.addRow(row); textArea = new JTable(model); // String END_OF_LINE = ","; // // String[] colName = { "Course", "Examiner", "Moderator", "Semester Available ", "Associated Programs", "Associated Majors"}; //// textArea.getTableHeader().setBackground(Color.WHITE); //// textArea.getTableHeader().setForeground(Color.BLUE); // // Font Tablefont = new Font("Details", Font.BOLD, 12); // // textArea.getTableHeader().setFont(Tablefont); // Object[][] object = new Object[100][100]; // int i = 0; // if (fileManage.size() != 0) { // for (fileManage book : fileManage) { // object[i][0] = fileManage.getCourseList(); // object[i][1] = fileManage.getNameList(); // object[i][2] = fileManage.getModeratorList(); // object[i][3] = fileManage.getSemesterList(); // object[i][4] = fileManage.getProgramList(); // object[i][5] = fileManage.getMajorList(); // // textArea = new JTable(object, colName); // } // } } } public void getData(){ nameList = fileManage.getNameList(); courseList = fileManage.getCourseList(); semesterList = fileManage.getSemesterList(); moderatorList = fileManage.getModeratorList(); majorList = fileManage.getMajorList(); programList = fileManage.getProgramList(); // textArea.(write()); } private JButton getCloseButton(){ return closeButton; } private void panels(){ JPanel panel = new JPanel(new GridLayout(1,1)); panel.setBorder(new EmptyBorder(5, 5, 5, 5)); JPanel rightPanel = new JPanel(new GridLayout(15,0,10,10)); rightPanel.setBorder(new EmptyBorder(15, 5, 5, 10)); JScrollPane scrollBarForTextArea=new JScrollPane(textArea,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED); panel.add(scrollBarForTextArea); frame.add(panel); frame.getContentPane().add(rightPanel,BorderLayout.EAST); rightPanel.add(saveCloseBtn); rightPanel.add(closeButton); closeButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { frame.dispose(); } }); saveCloseBtn.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { //saveBtn(); frame.dispose(); } }); frame.setSize(1000, 700); frame.setVisible(true); frame.setLocationRelativeTo(null); } // private void saveBtn(){ // File file = null; // FileWriter out=null; // try { // file = new File("Course.txt"); // out = new FileWriter(file); // out.write(textArea.getText()); // out.close(); // } catch (FileNotFoundException e) { // e.printStackTrace(); // } catch (IOException e) { // e.printStackTrace(); // } // JOptionPane.showMessageDialog(this, "File Successfully Updated"); // // } }

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  • Inheritance issue

    - by VenkateshGudipati
    hi Friends i am facing a issue in Inheritance i have a interface called Irewhizz interface irewhzz { void object save(object obj); void object getdata(object obj); } i write definition in different class like public user:irewhzz { public object save(object obj); { ....... } public object getdata(object obj); { ....... } } this is antoher class public client:irewhzz { public object save(object obj); { ....... } public object getdata(object obj); { ....... } } now i have different classes like public partial class RwUser { #region variables IRewhizzDataHelper irewhizz; IRewhizzRelationDataHelper irewhizzrelation; private string _firstName; private string _lastName; private string _middleName; private string _email; private string _website; private int _addressId; private string _city; private string _zipcode; private string _phone; private string _fax; //private string _location; private string _aboutMe; private string _username; private string _password; private string _securityQuestion; private string _securityQAnswer; private Guid _user_Id; private long _rwuserid; private byte[] _image; private bool _changepassword; private string _mobilephone; private int _role; #endregion //IRewhizz is the interface and its functions are implimented by UserDataHelper class //RwUser Class is inheriting the UserDataHelper Properties and functions. //Here UserDataHelper functions are called with Irewhizz Interface Object but not with the //UserDataHelper class Object It will resolves the unit testing conflict. #region Constructors public RwUser() : this(new UserDataHelper(), new RewhizzRelationalDataHelper()) { } public RwUser(IRewhizzDataHelper repositary, IRewhizzRelationDataHelper relationrepositary) { irewhizz = repositary; irewhizzrelation = relationrepositary; } #endregion #region Properties public int Role { get { return _role; } set { _role = value; } } public string MobilePhone { get { return _mobilephone; } set { _mobilephone = value; } } public bool ChangePassword { get { return _changepassword; } set { _changepassword = value; } } public byte[] Image { get { return _image; } set { _image = value; } } public string FirstName { get { return _firstName; } set { _firstName = value; } } public string LastName { get { return _lastName; } set { _lastName = value; } } public string MiddleName { get { return _middleName; } set { _middleName = value; } } public string Email { get { return _email; } set { _email = value; } } public string Website { get { return _website; } set { _website = value; } } public int AddressId { get { return _addressId; } set { _addressId = value; } } public string City { get { return _city; } set { _city = value; } } public string Zipcode { get { return _zipcode; } set { _zipcode = value; } } public string Phone { get { return _phone; } set { _phone = value; } } public string Fax { get { return _fax; } set { _fax = value; } } //public string Location //{ // get // { // return _location; // } // set // { // _location = value; // } //} public string AboutMe { get { return _aboutMe; } set { _aboutMe = value; } } public string username { get { return _username; } set { _username = value; } } public string password { get { return _password; } set { _password = value; } } public string SecurityQuestion { get { return _securityQuestion; } set { _securityQuestion = value; } } public string SecurityQAnswer { get { return _securityQAnswer; } set { _securityQAnswer = value; } } public Guid UserID { get { return _user_Id; } set { _user_Id = value; } } public long RwUserID { get { return _rwuserid; } set { _rwuserid = value; } } #endregion #region MemberFunctions // DataHelperDataContext db = new DataHelperDataContext(); // RewhizzDataHelper rwdh=new RewhizzDataHelper(); //It saves user information entered by user and returns the id of that user public object saveUserInfo(RwUser userObj) { userObj.UserID = irewhizzrelation.GetUserId(username); var res = irewhizz.saveData(userObj); return res; } //It returns the security questions for user registration } public class Agent : RwUser { IRewhizzDataHelper irewhizz; IRewhizzRelationDataHelper irewhizzrelation; private int _roleid; private int _speclisationid; private int[] _language; private string _brokaragecompany; private int _loctionType_lk; private string _rolename; private int[] _specialization; private string _agentID; private string _expDate; private string _regstates; private string _selLangs; private string _selSpels; private string _locations; public string Locations { get { return _locations; } set { _locations = value; } } public string SelectedLanguages { get { return _selLangs; } set { _selLangs = value; } } public string SelectedSpecialization { get { return _selSpels; } set { _selSpels = value; } } public string RegisteredStates { get { return _regstates; } set { _regstates = value; } } //private string _registeredStates; public string AgentID { get { return _agentID; } set { _agentID = value; } } public string ExpDate { get { return _expDate; } set { _expDate = value; } } private int[] _registeredStates; public SelectList RegisterStates { set; get; } public SelectList Languages { set; get; } public SelectList Specializations { set; get; } public int[] RegisterdStates { get { return _registeredStates; } set { _registeredStates = value; } } //public string RegisterdStates //{ // get // { // return _registeredStates; // } // set // { // _registeredStates = value; // } //} public int RoleId { get { return _roleid; } set { _roleid = value; } } public int SpeclisationId { get { return _speclisationid; } set { _speclisationid = value; } } public int[] Language { get { return _language; } set { _language = value; } } public int LocationTypeId { get { return _loctionType_lk; } set { _loctionType_lk = value; } } public string BrokarageCompany { get { return _brokaragecompany; } set { _brokaragecompany = value; } } public string Rolename { get { return _rolename; } set { _rolename = value; } } public int[] Specialization { get { return _specialization; } set { _specialization = value; } } public Agent() : this(new AgentDataHelper(), new RewhizzRelationalDataHelper()) { } public Agent(IRewhizzDataHelper repositary, IRewhizzRelationDataHelper relationrepositary) { irewhizz = repositary; irewhizzrelation = relationrepositary; } public void inviteclient() { //Code related to mailing } //DataHelperDataContext dataObj = new DataHelperDataContext(); //#region IRewhizzFactory Members //public List<object> getAgentInfo(string username) //{ // var res=dataObj.GetCompleteUserDetails(username); // return res.ToList(); // throw new NotImplementedException(); //} //public List<object> GetRegisterAgentData(string username) //{ // var res= dataObj.RegisteredUserdetails(username); // return res.ToList(); //} //public void saveAgentInfo(string username, string password, string firstname, string lastname, string middlename, string securityquestion, string securityQanswer) //{ // User userobj=new User(); // var result = dataObj.rw_Users_InsertUserInfo(firstname, middlename, lastname, dataObj.GetUserId(username), securityquestion, securityquestionanswer); // throw new NotImplementedException(); //} //#endregion public Agent updateData(Agent objectId) { objectId.UserID = irewhizzrelation.GetUserId(objectId.username); objectId = (Agent)irewhizz.updateData(objectId); return objectId; } public Agent GetAgentData(Agent agentodj) { agentodj.UserID = irewhizzrelation.GetUserId(agentodj.username); agentodj = (Agent)irewhizz.getData(agentodj); if (agentodj.RoleId != 0) agentodj.Rolename = (string)(string)irewhizzrelation.getValue(agentodj.RoleId); if (agentodj.RegisterdStates.Count() != 0) { List<SelectListItem> list = new List<SelectListItem>(); string regstates = ""; foreach (int i in agentodj.RegisterdStates) { SelectListItem listitem = new SelectListItem(); listitem.Value = i.ToString(); listitem.Text = (string)irewhizzrelation.getValue(i); list.Add(listitem); regstates += (string)irewhizzrelation.getValue(i) + ","; } SelectList selectlist = new SelectList(list, "Value", "Text"); agentodj.RegisterStates = selectlist; if(regstates!=null) agentodj.RegisteredStates = regstates.Remove(regstates.Length - 1); } if (agentodj.Language.Count() != 0) { List<SelectListItem> list = new List<SelectListItem>(); string selectedlang = ""; foreach (int i in agentodj.Language) { SelectListItem listitem = new SelectListItem(); listitem.Value = i.ToString(); listitem.Text = (string)irewhizzrelation.getValue(i); list.Add(listitem); selectedlang += (string)irewhizzrelation.getValue(i) + ","; } SelectList selectlist = new SelectList(list, "Value", "Text"); agentodj.Languages = selectlist; // agentodj.SelectedLanguages = selectedlang; } if (agentodj.Specialization.Count() != 0) { List<SelectListItem> list = new List<SelectListItem>(); string selectedspel = ""; foreach (int i in agentodj.Specialization) { SelectListItem listitem = new SelectListItem(); listitem.Value = i.ToString(); listitem.Text = (string)irewhizzrelation.getValue(i); list.Add(listitem); selectedspel += (string)irewhizzrelation.getValue(i) + ","; } SelectList selectlist = new SelectList(list, "Value", "Text"); agentodj.Specializations = selectlist; //agentodj.SelectedSpecialization = selectedspel; } return agentodj; } public void SaveImage(byte[] pic, String username) { irewhizzrelation.SaveImage(pic, username); } } now the issue is when ever i am calling agent class it is given error like null reference exception for rwuser class can any body give the solution thanks in advance

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  • jQuery, ASP.NET, and Browser History

    - by Stephen Walther
    One objection that people always raise against Ajax applications concerns browser history. Because an Ajax application updates its content by performing sneaky Ajax postbacks, the browser backwards and forwards buttons don’t work as you would normally expect. In a normal, non-Ajax application, when you click the browser back button, you return to a previous state of the application. For example, if you are paging through a set of movie records, you might return to the previous page of records. In an Ajax application, on the other hand, the browser backwards and forwards buttons do not work as you would expect. If you navigate to the second page in a list of records and click the backwards button, you won’t return to the previous page. Most likely, you will end up navigating away from the application entirely (which is very unexpected and irritating). Bookmarking presents a similar problem. You cannot bookmark a particular page of records in an Ajax application because the address bar does not reflect the state of the application. The Ajax Solution There is a solution to both of these problems. To solve both of these problems, you must take matters into your own hands and take responsibility for saving and restoring your application state yourself. Furthermore, you must ensure that the address bar gets updated to reflect the state of your application. In this blog entry, I demonstrate how you can take advantage of a jQuery library named bbq that enables you to control browser history (and make your Ajax application bookmarkable) in a cross-browser compatible way. The JavaScript Libraries In this blog entry, I take advantage of the following four JavaScript files: jQuery-1.4.2.js – The jQuery library. Available from the Microsoft Ajax CDN at http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js jquery.pager.js – Used to generate pager for navigating records. Available from http://plugins.jquery.com/project/Pager microtemplates.js – John Resig’s micro-templating library. Available from http://ejohn.org/blog/javascript-micro-templating/ jquery.ba-bbq.js – The Back Button and Query (BBQ) Library. Available from http://benalman.com/projects/jquery-bbq-plugin/ All of these libraries, with the exception of the Micro-templating library, are available under the MIT open-source license. The Ajax Application Let’s start by building a simple Ajax application that enables you to page through a set of movie database records, 3 records at a time. We’ll use my favorite database named MoviesDB. This database contains a Movies table that looks like this: We’ll create a data model for this database by taking advantage of the ADO.NET Entity Framework. The data model looks like this: Finally, we’ll expose the data to the universe with the help of a WCF Data Service named MovieService.svc. The code for the data service is contained in Listing 1. Listing 1 – MovieService.svc using System.Data.Services; using System.Data.Services.Common; namespace WebApplication1 { public class MovieService : DataService<MoviesDBEntities> { public static void InitializeService(DataServiceConfiguration config) { config.SetEntitySetAccessRule("Movies", EntitySetRights.AllRead); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; } } } The WCF Data Service in Listing 1 exposes the movies so that you can query the movie database table with URLs that looks like this: http://localhost:2474/MovieService.svc/Movies -- Returns all movies http://localhost:2474/MovieService.svc/Movies?$top=5 – Returns 5 movies The HTML page in Listing 2 enables you to page through the set of movies retrieved from the WCF Data Service. Listing 2 – Original.html <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Movies with History</title> <link href="Design/Pager.css" rel="stylesheet" type="text/css" /> </head> <body> <h1>Page <span id="pageNumber"></span> of <span id="pageCount"></span></h1> <div id="pager"></div> <br style="clear:both" /><br /> <div id="moviesContainer"></div> <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js" type="text/javascript"></script> <script src="App_Scripts/Microtemplates.js" type="text/javascript"></script> <script src="App_Scripts/jquery.pager.js" type="text/javascript"></script> <script type="text/javascript"> var pageSize = 3, pageIndex = 0; // Show initial page of movies showMovies(); function showMovies() { // Build OData query var query = "/MovieService.svc" // base URL + "/Movies" // top-level resource + "?$skip=" + pageIndex * pageSize // skip records + "&$top=" + pageSize // take records + " &$inlinecount=allpages"; // include total count of movies // Make call to WCF Data Service $.ajax({ dataType: "json", url: query, success: showMoviesComplete }); } function showMoviesComplete(result) { // unwrap results var movies = result["d"]["results"]; var movieCount = result["d"]["__count"] // Show movies using template var showMovie = tmpl("<li><%=Id%> - <%=Title %></li>"); var html = ""; for (var i = 0; i < movies.length; i++) { html += showMovie(movies[i]); } $("#moviesContainer").html(html); // show pager $("#pager").pager({ pagenumber: (pageIndex + 1), pagecount: Math.ceil(movieCount / pageSize), buttonClickCallback: selectPage }); // Update page number and page count $("#pageNumber").text(pageIndex + 1); $("#pageCount").text(movieCount); } function selectPage(pageNumber) { pageIndex = pageNumber - 1; showMovies(); } </script> </body> </html> The page in Listing 3 has the following three functions: showMovies() – Performs an Ajax call against the WCF Data Service to retrieve a page of movies. showMoviesComplete() – When the Ajax call completes successfully, this function displays the movies by using a template. This function also renders the pager user interface. selectPage() – When you select a particular page by clicking on a page number in the pager UI, this function updates the current page index and calls the showMovies() function. Figure 1 illustrates what the page looks like when it is opened in a browser. Figure 1 If you click the page numbers then the browser history is not updated. Clicking the browser forward and backwards buttons won’t move you back and forth in browser history. Furthermore, the address displayed in the address bar does not change when you navigate to different pages. You cannot bookmark any page except for the first page. Adding Browser History The Back Button and Query (bbq) library enables you to add support for browser history and bookmarking to a jQuery application. The bbq library supports two important methods: jQuery.bbq.pushState(object) – Adds state to browser history. jQuery.bbq.getState(key) – Gets state from browser history. The bbq library also supports one important event: hashchange – This event is raised when the part of an address after the hash # is changed. The page in Listing 3 demonstrates how to use the bbq library to add support for browser navigation and bookmarking to an Ajax page. Listing 3 – Default.html <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Movies with History</title> <link href="Design/Pager.css" rel="stylesheet" type="text/css" /> </head> <body> <h1>Page <span id="pageNumber"></span> of <span id="pageCount"></span></h1> <div id="pager"></div> <br style="clear:both" /><br /> <div id="moviesContainer"></div> <script src="http://ajax.microsoft.com/ajax/jquery/jquery-1.4.2.js" type="text/javascript"></script> <script src="App_Scripts/jquery.ba-bbq.js" type="text/javascript"></script> <script src="App_Scripts/Microtemplates.js" type="text/javascript"></script> <script src="App_Scripts/jquery.pager.js" type="text/javascript"></script> <script type="text/javascript"> var pageSize = 3, pageIndex = 0; $(window).bind('hashchange', function (e) { pageIndex = e.getState("pageIndex") || 0; pageIndex = parseInt(pageIndex); showMovies(); }); $(window).trigger('hashchange'); function showMovies() { // Build OData query var query = "/MovieService.svc" // base URL + "/Movies" // top-level resource + "?$skip=" + pageIndex * pageSize // skip records + "&$top=" + pageSize // take records +" &$inlinecount=allpages"; // include total count of movies // Make call to WCF Data Service $.ajax({ dataType: "json", url: query, success: showMoviesComplete }); } function showMoviesComplete(result) { // unwrap results var movies = result["d"]["results"]; var movieCount = result["d"]["__count"] // Show movies using template var showMovie = tmpl("<li><%=Id%> - <%=Title %></li>"); var html = ""; for (var i = 0; i < movies.length; i++) { html += showMovie(movies[i]); } $("#moviesContainer").html(html); // show pager $("#pager").pager({ pagenumber: (pageIndex + 1), pagecount: Math.ceil(movieCount / pageSize), buttonClickCallback: selectPage }); // Update page number and page count $("#pageNumber").text(pageIndex + 1); $("#pageCount").text(movieCount); } function selectPage(pageNumber) { pageIndex = pageNumber - 1; $.bbq.pushState({ pageIndex: pageIndex }); } </script> </body> </html> Notice the first chunk of JavaScript code in Listing 3: $(window).bind('hashchange', function (e) { pageIndex = e.getState("pageIndex") || 0; pageIndex = parseInt(pageIndex); showMovies(); }); $(window).trigger('hashchange'); When the hashchange event occurs, the current pageIndex is retrieved by calling the e.getState() method. The value is returned as a string and the value is cast to an integer by calling the JavaScript parseInt() function. Next, the showMovies() method is called to display the page of movies. The $(window).trigger() method is called to raise the hashchange event so that the initial page of records will be displayed. When you click a page number, the selectPage() method is invoked. This method adds the current page index to the address by calling the following method: $.bbq.pushState({ pageIndex: pageIndex }); For example, if you click on page number 2 then page index 1 is saved to the URL. The URL looks like this: Notice that when you click on page 2 then the browser address is updated to look like: /Default.htm#pageIndex=1 If you click on page 3 then the browser address is updated to look like: /Default.htm#pageIndex=2 Because the browser address is updated when you navigate to a new page number, the browser backwards and forwards button will work to navigate you backwards and forwards through the page numbers. When you click page 2, and click the backwards button, you will navigate back to page 1. Furthermore, you can bookmark a particular page of records. For example, if you bookmark the URL /Default.htm#pageIndex=1 then you will get the second page of records whenever you open the bookmark. Summary You should not avoid building Ajax applications because of worries concerning browser history or bookmarks. By taking advantage of a JavaScript library such as the bbq library, you can make your Ajax applications behave in exactly the same way as a normal web application.

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  • jQuery Templates with ASP.NET MVC

    - by hajan
    In my three previous blogs, I’ve shown how to use Templates in your ASPX website. Introduction to jQuery TemplatesjQuery Templates - tmpl(), template() and tmplItem()jQuery Templates - {Supported Tags}Now, I will show one real-world example which you may use it in your daily work of developing applications with ASP.NET MVC and jQuery. In the following example I will use Pubs database so that I will retrieve values from the authors table. To access the data, I’m using Entity Framework. Let’s pass throughout each step of the scenario: 1. Create new ASP.NET MVC Web application 2. Add new View inside Home folder but do not select a master page, and add Controller for your View 3. BODY code in the HTML <body>     <div>         <h1>Pubs Authors</h1>         <div id="authorsList"></div>     </div> </body> As you can see  in the body we have only one H1 tag and a div with id authorsList where we will append the data from database.   4. Now, I’ve created Pubs model which is connected to the Pub database and I’ve selected only the authors table in my EDMX model. You can use your own database. 5. Next, lets create one method of JsonResult type which will get the data from database and serialize it into JSON string. public JsonResult GetAuthors() {     pubsEntities pubs = new pubsEntities();     var authors = pubs.authors.ToList();     return Json(authors, JsonRequestBehavior.AllowGet); } So, I’m creating object instance of pubsEntities and get all authors in authors list. Then returning the authors list by serializing it to JSON using Json method. The JsonRequestBehaviour.AllowGet parameter is used to make the GET requests from the client become allowed. By default in ASP.NET MVC 2 the GET is not allowed because of security issue with JSON hijacking.   6. Next, lets create jQuery AJAX function which will call the GetAuthors method. We will use $.getJSON jQuery method. <script language="javascript" type="text/javascript">     $(function () {         $.getJSON("GetAuthors", "", function (data) {             $("#authorsTemplate").tmpl(data).appendTo("#authorsList");         });     }); </script>   Once the web page is downloaded, the method will be called. The first parameter of $.getJSON() is url string in our case the method name. The second parameter (which in the example is empty string) is the key value pairs that will be send to the server, and the third function is the callback function or the result which is going to be returned from the server. Inside the callback function we have code that renders data with template which has id #authorsTemplate and appends it to element which has #authorsList ID.   7. The jQuery Template <script id="authorsTemplate" type="text/html">     <div id="author">         ${au_lname} ${au_fname}         <div id="address">${address}, ${city}</div>         <div id="contractType">                     {{if contract}}             <font color="green">Has contract with the publishing house</font>         {{else}}             <font color="red">Without contract</font>         {{/if}}         <br />         <em> ${printMessage(state)} </em>         <br />                     </div>     </div> </script> As you can see, I have tags containing fields (au_lname, au_fname… etc.) that corresponds to the table in the EDMX model which is the same as in the database. One more thing to note here is that I have printMessage(state) function which is called inside ${ expression/function/field } tag. The printMessage function <script language="javascript" type="text/javascript">     function printMessage(s) {         if (s=="CA") return "The author is from California";         else return "The author is not from California";     } </script> So, if state is “CA” print “The author is from California” else “The author is not from California”   HERE IS THE COMPLETE ASPX CODE <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head runat="server">     <title>Database Example :: jQuery Templates</title>     <style type="text/css">         body           {             font-family:Verdana,Arial,Courier New, Sans-Serif;             color:Black;             padding:2px, 2px, 2px, 2px;             background-color:#FF9640;         }         #author         {             display:block;             float:left;             text-decoration:none;             border:1px solid black;             background-color:White;             padding:20px 20px 20px 20px;             margin-top:2px;             margin-right:2px;             font-family:Verdana;             font-size:12px;             width:200px;             height:70px;}         #address           {             font-style:italic;             color:Blue;             font-size:12px;             font-family:Verdana;         }         .author_hover {background-color:Yellow;}     </style>     <script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.min.js" type="text/javascript"></script>     <script src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js" type="text/javascript"></script>     <script language="javascript" type="text/javascript">         function printMessage(s) {             if (s=="CA") return "The author is from California";             else return "The author is not from California";         }     </script>     <script id="authorsTemplate" type="text/html">         <div id="author">             ${au_lname} ${au_fname}             <div id="address">${address}, ${city}</div>             <div id="contractType">                         {{if contract}}                 <font color="green">Has contract with the publishing house</font>             {{else}}                 <font color="red">Without contract</font>             {{/if}}             <br />             <em> ${printMessage(state)} </em>             <br />                         </div>         </div>     </script>     <script language="javascript" type="text/javascript">         $(function () {             $.getJSON("GetAuthors", "", function (data) {                 $("#authorsTemplate").tmpl(data).appendTo("#authorsList");             });         });     </script> </head>     <body>     <div id="title">Pubs Authors</div>     <div id="authorsList"></div> </body> </html> So, in the complete example you also have the CSS style I’m using to stylize the output of my page. Here is print screen of the end result displayed on the web page: You can download the complete source code including examples shown in my previous blog posts about jQuery templates and PPT presentation from my last session I had in the local .NET UG meeting in the following DOWNLOAD LINK. Do let me know your feedback. Regards, Hajan

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  • Troubleshoot Perl module installation on Mac OS X

    - by Daniel Standage
    I'm trying to install the Perl module Set::IntervalTree on Mac OS X. I recently installed it today on an Ubuntu box with no problem. I simply started cpan, entered install Set:IntervalTree, and it all worked out. However, the installation failed on Mac OS X--it spits out a huge list of compiler errors (below). How would I troubleshoot this. I don't even know where to begin. cpan[1]> install Set::IntervalTree CPAN: Storable loaded ok (v2.18) Going to read /Users/standage/.cpan/Metadata Database was generated on Fri, 14 Jan 2011 02:58:42 GMT CPAN: YAML loaded ok (v0.72) Going to read /Users/standage/.cpan/build/ ............................................................................DONE Found 1 old build, restored the state of 1 Running install for module 'Set::IntervalTree' Running make for B/BE/BENBOOTH/Set-IntervalTree-0.01.tar.gz CPAN: Digest::SHA loaded ok (v5.45) CPAN: Compress::Zlib loaded ok (v2.008) Checksum for /Users/standage/.cpan/sources/authors/id/B/BE/BENBOOTH/Set-IntervalTree-0.01.tar.gz ok Scanning cache /Users/standage/.cpan/build for sizes ............................................................................DONE x Set-IntervalTree-0.01/ x Set-IntervalTree-0.01/src/ x Set-IntervalTree-0.01/src/Makefile x Set-IntervalTree-0.01/src/interval_tree.h x Set-IntervalTree-0.01/src/test_main.cc x Set-IntervalTree-0.01/lib/ x Set-IntervalTree-0.01/lib/Set/ x Set-IntervalTree-0.01/lib/Set/IntervalTree.pm x Set-IntervalTree-0.01/Changes x Set-IntervalTree-0.01/MANIFEST x Set-IntervalTree-0.01/t/ x Set-IntervalTree-0.01/t/Set-IntervalTree.t x Set-IntervalTree-0.01/typemap x Set-IntervalTree-0.01/perlobject.map x Set-IntervalTree-0.01/IntervalTree.xs x Set-IntervalTree-0.01/Makefile.PL x Set-IntervalTree-0.01/README x Set-IntervalTree-0.01/META.yml CPAN: File::Temp loaded ok (v0.18) CPAN.pm: Going to build B/BE/BENBOOTH/Set-IntervalTree-0.01.tar.gz Checking if your kit is complete... Looks good Writing Makefile for Set::IntervalTree cp lib/Set/IntervalTree.pm blib/lib/Set/IntervalTree.pm AutoSplitting blib/lib/Set/IntervalTree.pm (blib/lib/auto/Set/IntervalTree) /usr/bin/perl /System/Library/Perl/5.10.0/ExtUtils/xsubpp -C++ -typemap /System/Library/Perl/5.10.0/ExtUtils/typemap -typemap perlobject.map -typemap typemap IntervalTree.xs > IntervalTree.xsc && mv IntervalTree.xsc IntervalTree.c g++ -c -Isrc -arch x86_64 -arch i386 -arch ppc -g -pipe -fno-common -DPERL_DARWIN -fno-strict-aliasing -I/usr/local/include -g -O0 -DVERSION=\"0.01\" -DXS_VERSION=\"0.01\" "-I/System/Library/Perl/5.10.0/darwin-thread-multi-2level/CORE" -Isrc IntervalTree.c In file included from /usr/include/c++/4.2.1/bits/basic_ios.h:44, from /usr/include/c++/4.2.1/ios:50, from /usr/include/c++/4.2.1/ostream:45, from /usr/include/c++/4.2.1/iostream:45, from IntervalTree.xs:16: /usr/include/c++/4.2.1/bits/locale_facets.h:4420:40: error: macro "do_open" requires 7 arguments, but only 2 given /usr/include/c++/4.2.1/bits/locale_facets.h:4467:34: error: macro "do_close" requires 2 arguments, but only 1 given /usr/include/c++/4.2.1/bits/locale_facets.h:4486:55: error: macro "do_open" requires 7 arguments, but only 2 given /usr/include/c++/4.2.1/bits/locale_facets.h:4513:23: error: macro "do_close" requires 2 arguments, but only 1 given In file included from /usr/include/c++/4.2.1/bits/locale_facets.h:4599, from /usr/include/c++/4.2.1/bits/basic_ios.h:44, from /usr/include/c++/4.2.1/ios:50, from /usr/include/c++/4.2.1/ostream:45, from /usr/include/c++/4.2.1/iostream:45, from IntervalTree.xs:16: /usr/include/c++/4.2.1/i686-apple-darwin10/x86_64/bits/messages_members.h:58:38: error: macro "do_open" requires 7 arguments, but only 2 given /usr/include/c++/4.2.1/i686-apple-darwin10/x86_64/bits/messages_members.h:67:71: error: macro "do_open" requires 7 arguments, but only 2 given /usr/include/c++/4.2.1/i686-apple-darwin10/x86_64/bits/messages_members.h:78:39: error: macro "do_close" requires 2 arguments, but only 1 given In file included from /usr/include/c++/4.2.1/bits/basic_ios.h:44, from /usr/include/c++/4.2.1/ios:50, from /usr/include/c++/4.2.1/ostream:45, from /usr/include/c++/4.2.1/iostream:45, from IntervalTree.xs:16: /usr/include/c++/4.2.1/bits/locale_facets.h:4486: error: ‘do_open’ declared as a ‘virtual’ field /usr/include/c++/4.2.1/bits/locale_facets.h:4486: error: expected ‘;’ before ‘const’ /usr/include/c++/4.2.1/bits/locale_facets.h:4513: error: variable or field ‘do_close’ declared void /usr/include/c++/4.2.1/bits/locale_facets.h:4513: error: expected ‘;’ before ‘const’ In file included from /usr/include/c++/4.2.1/bits/locale_facets.h:4599, from /usr/include/c++/4.2.1/bits/basic_ios.h:44, from /usr/include/c++/4.2.1/ios:50, from /usr/include/c++/4.2.1/ostream:45, from /usr/include/c++/4.2.1/iostream:45, from IntervalTree.xs:16: /usr/include/c++/4.2.1/i686-apple-darwin10/x86_64/bits/messages_members.h:67: error: expected initializer before ‘const’ /usr/include/c++/4.2.1/i686-apple-darwin10/x86_64/bits/messages_members.h:78: error: expected initializer before ‘const’ In file included from IntervalTree.xs:19: src/interval_tree.h:95: error: type/value mismatch at argument 1 in template parameter list for ‘template<class _Tp, class _Alloc> class std::vector’ src/interval_tree.h:95: error: expected a type, got ‘IntervalTree<T,N>::it_recursion_node’ src/interval_tree.h:95: error: template argument 2 is invalid src/interval_tree.h: In constructor ‘IntervalTree<T, N>::IntervalTree()’: src/interval_tree.h:130: error: expected type-specifier src/interval_tree.h:130: error: expected `;' src/interval_tree.h:135: error: expected type-specifier src/interval_tree.h:135: error: expected `;' src/interval_tree.h:141: error: request for member ‘push_back’ in ‘((IntervalTree<T, N>*)this)->IntervalTree<T, N>::recursionNodeStack’, which is of non-class type ‘int’ src/interval_tree.h: In member function ‘void IntervalTree<T, N>::LeftRotate(IntervalTree<T, N>::Node*)’: src/interval_tree.h:178: error: ‘y’ was not declared in this scope src/interval_tree.h: In member function ‘void IntervalTree<T, N>::RightRotate(IntervalTree<T, N>::Node*)’: src/interval_tree.h:240: error: ‘x’ was not declared in this scope src/interval_tree.h: In member function ‘void IntervalTree<T, N>::TreeInsertHelp(IntervalTree<T, N>::Node*)’: src/interval_tree.h:298: error: ‘x’ was not declared in this scope src/interval_tree.h:299: error: ‘y’ was not declared in this scope src/interval_tree.h: In member function ‘typename IntervalTree<T, N>::Node* IntervalTree<T, N>::insert(const T&, N, N)’: src/interval_tree.h:375: error: ‘y’ was not declared in this scope src/interval_tree.h:376: error: ‘x’ was not declared in this scope src/interval_tree.h:377: error: ‘newNode’ was not declared in this scope src/interval_tree.h:379: error: expected type-specifier src/interval_tree.h:379: error: expected `;' src/interval_tree.h: In member function ‘typename IntervalTree<T, N>::Node* IntervalTree<T, N>::GetSuccessorOf(IntervalTree<T, N>::Node*) const’: src/interval_tree.h:450: error: ‘y’ was not declared in this scope src/interval_tree.h: In member function ‘typename IntervalTree<T, N>::Node* IntervalTree<T, N>::GetPredecessorOf(IntervalTree<T, N>::Node*) const’: src/interval_tree.h:483: error: ‘y’ was not declared in this scope src/interval_tree.h: In destructor ‘IntervalTree<T, N>::~IntervalTree()’: src/interval_tree.h:546: error: ‘x’ was not declared in this scope src/interval_tree.h:547: error: type/value mismatch at argument 1 in template parameter list for ‘template<class _Tp, class _Alloc> class std::vector’ src/interval_tree.h:547: error: expected a type, got ‘(IntervalTree<T,N>::Node * <expression error>)’ src/interval_tree.h:547: error: template argument 2 is invalid src/interval_tree.h:547: error: invalid type in declaration before ‘;’ token src/interval_tree.h:551: error: request for member ‘push_back’ in ‘stuffToFree’, which is of non-class type ‘int’ src/interval_tree.h:554: error: request for member ‘push_back’ in ‘stuffToFree’, which is of non-class type ‘int’ src/interval_tree.h:557: error: request for member ‘empty’ in ‘stuffToFree’, which is of non-class type ‘int’ src/interval_tree.h:558: error: request for member ‘back’ in ‘stuffToFree’, which is of non-class type ‘int’ src/interval_tree.h:559: error: request for member ‘pop_back’ in ‘stuffToFree’, which is of non-class type ‘int’ src/interval_tree.h:561: error: request for member ‘push_back’ in ‘stuffToFree’, which is of non-class type ‘int’ src/interval_tree.h:564: error: request for member ‘push_back’ in ‘stuffToFree’, which is of non-class type ‘int’ src/interval_tree.h: In member function ‘void IntervalTree<T, N>::DeleteFixUp(IntervalTree<T, N>::Node*)’: src/interval_tree.h:613: error: ‘w’ was not declared in this scope src/interval_tree.h:614: error: ‘rootLeft’ was not declared in this scope src/interval_tree.h: In member function ‘T IntervalTree<T, N>::remove(IntervalTree<T, N>::Node*)’: src/interval_tree.h:697: error: ‘y’ was not declared in this scope src/interval_tree.h:698: error: ‘x’ was not declared in this scope src/interval_tree.h: In member function ‘std::vector<T, std::allocator<_CharT> > IntervalTree<T, N>::fetch(N, N)’: src/interval_tree.h:819: error: ‘x’ was not declared in this scope src/interval_tree.h:833: error: invalid types ‘int[size_t]’ for array subscript src/interval_tree.h:836: error: request for member ‘push_back’ in ‘((IntervalTree<T, N>*)this)->IntervalTree<T, N>::recursionNodeStack’, which is of non-class type ‘int’ src/interval_tree.h:837: error: request for member ‘back’ in ‘((IntervalTree<T, N>*)this)->IntervalTree<T, N>::recursionNodeStack’, which is of non-class type ‘int’ src/interval_tree.h:838: error: request for member ‘back’ in ‘((IntervalTree<T, N>*)this)->IntervalTree<T, N>::recursionNodeStack’, which is of non-class type ‘int’ src/interval_tree.h:839: error: request for member ‘back’ in ‘((IntervalTree<T, N>*)this)->IntervalTree<T, N>::recursionNodeStack’, which is of non-class type ‘int’ src/interval_tree.h:840: error: request for member ‘size’ in ‘((IntervalTree<T, N>*)this)->IntervalTree<T, N>::recursionNodeStack’, which is of non-class type ‘int’ src/interval_tree.h:846: error: request for member ‘size’ in ‘((IntervalTree<T, N>*)this)->IntervalTree<T, N>::recursionNodeStack’, which is of non-class type ‘int’ src/interval_tree.h:847: error: expected `;' before ‘back’ src/interval_tree.h:848: error: request for member ‘pop_back’ in ‘((IntervalTree<T, N>*)this)->IntervalTree<T, N>::recursionNodeStack’, which is of non-class type ‘int’ src/interval_tree.h:850: error: ‘back’ was not declared in this scope src/interval_tree.h:853: error: invalid types ‘int[size_t]’ for array subscript IntervalTree.c: In function ‘void boot_Set__IntervalTree(PerlInterpreter*, CV*)’: IntervalTree.c:365: warning: deprecated conversion from string constant to ‘char*’ src/interval_tree.h: In constructor ‘IntervalTree<T, N>::IntervalTree() [with T = std::tr1::shared_ptr<sv>, N = long int]’: IntervalTree.c:67: instantiated from here src/interval_tree.h:130: error: cannot convert ‘int*’ to ‘IntervalTree<std::tr1::shared_ptr<sv>, long int>::Node*’ in assignment src/interval_tree.h:135: error: cannot convert ‘int*’ to ‘IntervalTree<std::tr1::shared_ptr<sv>, long int>::Node*’ in assignment ...blah blah blah... ...blah blah blah... ...blah blah blah... ...blah blah blah... ...blah blah blah... ...blah blah blah... src/interval_tree.h:848: error: request for member ‘pop_back’ in ‘((IntervalTree<T, N>*)this)->IntervalTree<T, N>::recursionNodeStack’, which is of non-class type ‘int’ src/interval_tree.h:850: error: ‘back’ was not declared in this scope src/interval_tree.h:853: error: invalid types ‘int[size_t]’ for array subscript IntervalTree.c: In function ‘void boot_Set__IntervalTree(PerlInterpreter*, CV*)’: IntervalTree.c:365: warning: deprecated conversion from string constant to ‘char*’ src/interval_tree.h: In constructor ‘IntervalTree<T, N>::IntervalTree() [with T = std::tr1::shared_ptr<sv>, N = long int]’: IntervalTree.c:67: instantiated from here src/interval_tree.h:130: error: cannot convert ‘int*’ to ‘IntervalTree<std::tr1::shared_ptr<sv>, long int>::Node*’ in assignment src/interval_tree.h:135: error: cannot convert ‘int*’ to ‘IntervalTree<std::tr1::shared_ptr<sv>, long int>::Node*’ in assignment src/interval_tree.h: In member function ‘typename IntervalTree<T, N>::Node* IntervalTree<T, N>::insert(const T&, N, N) [with T = std::tr1::shared_ptr<sv>, N = long int]’: IntervalTree.xs:57: instantiated from here src/interval_tree.h:375: error: dependent-name ‘IntervalTree<T,N>::Node’ is parsed as a non-type, but instantiation yields a type src/interval_tree.h:375: note: say ‘typename IntervalTree<T,N>::Node’ if a type is meant src/interval_tree.h:376: error: dependent-name ‘IntervalTree<T,N>::Node’ is parsed as a non-type, but instantiation yields a type src/interval_tree.h:376: note: say ‘typename IntervalTree<T,N>::Node’ if a type is meant src/interval_tree.h:377: error: dependent-name ‘IntervalTree<T,N>::Node’ is parsed as a non-type, but instantiation yields a type src/interval_tree.h:377: note: say ‘typename IntervalTree<T,N>::Node’ if a type is meant src/interval_tree.h: In member function ‘std::vector<T, std::allocator<_CharT> > IntervalTree<T, N>::fetch(N, N) [with T = std::tr1::shared_ptr<sv>, N = long int]’: IntervalTree.xs:65: instantiated from here src/interval_tree.h:819: error: dependent-name ‘IntervalTree<T,N>::Node’ is parsed as a non-type, but instantiation yields a type src/interval_tree.h:819: note: say ‘typename IntervalTree<T,N>::Node’ if a type is meant IntervalTree.xs:65: instantiated from here src/interval_tree.h:847: error: dependent-name ‘IntervalTree<T,N>::it_recursion_node’ is parsed as a non-type, but instantiation yields a type src/interval_tree.h:847: note: say ‘typename IntervalTree<T,N>::it_recursion_node’ if a type is meant src/interval_tree.h: In destructor ‘IntervalTree<T, N>::~IntervalTree() [with T = std::tr1::shared_ptr<sv>, N = long int]’: IntervalTree.c:205: instantiated from here src/interval_tree.h:546: error: dependent-name ‘IntervalTree<T,N>::Node’ is parsed as a non-type, but instantiation yields a type src/interval_tree.h:546: note: say ‘typename IntervalTree<T,N>::Node’ if a type is meant src/interval_tree.h: In member function ‘void IntervalTree<T, N>::TreeInsertHelp(IntervalTree<T, N>::Node*) [with T = std::tr1::shared_ptr<sv>, N = long int]’: src/interval_tree.h:380: instantiated from ‘typename IntervalTree<T, N>::Node* IntervalTree<T, N>::insert(const T&, N, N) [with T = std::tr1::shared_ptr<sv>, N = long int]’ IntervalTree.xs:57: instantiated from here src/interval_tree.h:298: error: dependent-name ‘IntervalTree<T,N>::Node’ is parsed as a non-type, but instantiation yields a type src/interval_tree.h:298: note: say ‘typename IntervalTree<T,N>::Node’ if a type is meant src/interval_tree.h:299: error: dependent-name ‘IntervalTree<T,N>::Node’ is parsed as a non-type, but instantiation yields a type src/interval_tree.h:299: note: say ‘typename IntervalTree<T,N>::Node’ if a type is meant src/interval_tree.h: In member function ‘void IntervalTree<T, N>::LeftRotate(IntervalTree<T, N>::Node*) [with T = std::tr1::shared_ptr<sv>, N = long int]’: src/interval_tree.h:395: instantiated from ‘typename IntervalTree<T, N>::Node* IntervalTree<T, N>::insert(const T&, N, N) [with T = std::tr1::shared_ptr<sv>, N = long int]’ IntervalTree.xs:57: instantiated from here src/interval_tree.h:178: error: dependent-name ‘IntervalTree<T,N>::Node’ is parsed as a non-type, but instantiation yields a type src/interval_tree.h:178: note: say ‘typename IntervalTree<T,N>::Node’ if a type is meant src/interval_tree.h: In member function ‘void IntervalTree<T, N>::RightRotate(IntervalTree<T, N>::Node*) [with T = std::tr1::shared_ptr<sv>, N = long int]’: src/interval_tree.h:399: instantiated from ‘typename IntervalTree<T, N>::Node* IntervalTree<T, N>::insert(const T&, N, N) [with T = std::tr1::shared_ptr<sv>, N = long int]’ IntervalTree.xs:57: instantiated from here src/interval_tree.h:240: error: dependent-name ‘IntervalTree<T,N>::Node’ is parsed as a non-type, but instantiation yields a type src/interval_tree.h:240: note: say ‘typename IntervalTree<T,N>::Node’ if a type is meant lipo: can't open input file: /var/tmp//ccLthuaw.out (No such file or directory) make: *** [IntervalTree.o] Error 1 BENBOOTH/Set-IntervalTree-0.01.tar.gz make -- NOT OK Running make test Can't test without successful make Running make install Make had returned bad status, install seems impossible Failed during this command: BENBOOTH/Set-IntervalTree-0.01.tar.gz : make NO

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  • I need help on my C++ assignment using MS Visual C++

    - by krayzwytie
    Ok, so I don't want you to do my homework for me, but I'm a little lost with this final assignment and need all the help I can get. Learning about programming is tough enough, but doing it online is next to impossible for me... Now, to get to the program, I am going to paste what I have so far. This includes mostly //comments and what I have written so far. If you can help me figure out where all the errors are and how to complete the assignment, I will really appreciate it. Like I said, I don't want you to do my homework for me (it's my final), but any constructive criticism is welcome. This is my final assignment for this class and it is due tomorrow (Sunday before midnight, Arizona time). This is the assignment: Examine the following situation: o Your company, Datamax, Inc., is in the process of automating its payroll systems. Your manager has asked you to create a program that calculates overtime pay for all employees. Your program must take into account the employee’s salary, total hours worked, and hours worked more than 40 in a week, and then provide an output that is useful and easily understood by company management. • Compile your program utilizing the following background information and the code outline in Appendix D (included in the code section). • Submit your project as an attachment including the code and the output. Company Background: o Three employees: Mark, John, and Mary o The end user needs to be prompted for three specific pieces of input—name, hours worked, and hourly wage. o Calculate overtime if input is greater than 40 hours per week. o Provide six test plans to verify the logic within the program. o Plan 1 must display the proper information for employee #1 with overtime pay. o Plan 2 must display the proper information for employee #1 with no overtime pay. o Plans 3-6 are duplicates of plan 1 and 2 but for the other employees. Program Requirements: o Define a base class to use for the entire program. o The class holds the function calls and the variables related to the overtime pay calculations. o Define one object per employee. Note there will be three employees. o Your program must take the objects created and implement calculations based on total salaries, total hours, and the total number of overtime hours. See the Employee Summary Data section of the sample output. Logic Steps to Complete Your Program: o Define your base class. o Define your objects from your base class. o Prompt for user input, updating your object classes for all three users. o Implement your overtime pay calculations. o Display overtime or regular time pay calculations. See the sample output below. o Implement object calculations by summarizing your employee objects and display the summary information in the example below. And this is the code: // Final_Project.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include <iostream> #include <string> #include <iomanip> using namespace std; // //CLASS DECLARATION SECTION // class CEmployee { public: void ImplementCalculations(string EmployeeName, double hours, double wage); void DisplayEmployInformation(void); void Addsomethingup (CEmployee, CEmployee, CEmployee); string EmployeeName ; int hours ; int overtime_hours ; int iTotal_hours ; int iTotal_OvertimeHours ; float wage ; float basepay ; float overtime_pay ; float overtime_extra ; float iTotal_salaries ; float iIndividualSalary ; }; int main() { system("cls"); cout << "Welcome to the Employee Pay Center"; /* Use this section to define your objects. You will have one object per employee. You have only three employees. The format is your class name and your object name. */ std::cout << "Please enter Employee's Name: "; std::cin >> EmployeeName; std::cout << "Please enter Total Hours for (EmployeeName): "; std::cin >> hours; std::cout << "Please enter Base Pay for(EmployeeName): "; std::cin >> basepay; /* Here you will prompt for the first employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Example of Prompts Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will prompt for the second employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will prompt for the third employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will implement a function call to implement the employ calcuations for each object defined above. You will do this for each of the three employees or objects. The format for this step is the following: [(object name.function name(objectname.name, objectname.hours, objectname.wage)] ; */ /* This section you will send all three objects to a function that will add up the the following information: - Total Employee Salaries - Total Employee Hours - Total Overtime Hours The format for this function is the following: - Define a new object. - Implement function call [objectname.functionname(object name 1, object name 2, object name 3)] /* } //End of Main Function void CEmployee::ImplementCalculations (string EmployeeName, double hours, double wage){ //Initialize overtime variables overtime_hours=0; overtime_pay=0; overtime_extra=0; if (hours > 40) { /* This section is for the basic calculations for calculating overtime pay. - base pay = 40 hours times the hourly wage - overtime hours = hours worked – 40 - overtime pay = hourly wage * 1.5 - overtime extra pay over 40 = overtime hours * overtime pay - salary = overtime money over 40 hours + your base pay */ /* Implement function call to output the employee information. Function is defined below. */ } // if (hours > 40) else { /* Here you are going to calculate the hours less than 40 hours. - Your base pay is = your hours worked times your wage - Salary = your base pay */ /* Implement function call to output the employee information. Function is defined below. */ } // End of the else } //End of Primary Function void CEmployee::DisplayEmployInformation(); { // This function displays all the employee output information. /* This is your cout statements to display the employee information: Employee Name ............. = Base Pay .................. = Hours in Overtime ......... = Overtime Pay Amount........ = Total Pay ................. = */ } // END OF Display Employee Information void CEmployee::Addsomethingup (CEmployee Employ1, CEmployee Employ2) { // Adds two objects of class Employee passed as // function arguments and saves them as the calling object's data member values. /* Add the total hours for objects 1, 2, and 3. Add the salaries for each object. Add the total overtime hours. */ /* Then display the information below. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%% EMPLOYEE SUMMARY DATA%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%% Total Employee Salaries ..... = 576.43 %%%% Total Employee Hours ........ = 108 %%%% Total Overtime Hours......... = 5 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% */ } // End of function

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  • Error compiling / linking e text editor on Linux

    - by jckdnk111
    The code compiles without too much complaint, but the last step fails with the error below. There is some discussion about it on the e forum, but still no answer. [LD] e ../external/out.release/lib/libpcre.a(pcre_tables.o):(.rodata+0x0): multiple definition of `_pcre_OP_lengths' .objs.release/cx_pcre_tables.o:(.rodata+0x0): first defined here ../external/out.release/lib/libpcre.a(pcre_tables.o):(.rodata+0x70): multiple definition of `_pcre_utf8_table1' .objs.release/cx_pcre_tables.o:(.rodata+0x70): first defined here ../external/out.release/lib/libpcre.a(pcre_tables.o):(.rodata+0x88): multiple definition of `_pcre_utf8_table1_size' .objs.release/cx_pcre_tables.o:(.rodata+0x88): first defined here ../external/out.release/lib/libpcre.a(pcre_tables.o):(.rodata+0x8c): multiple definition of `_pcre_utf8_table2' .objs.release/cx_pcre_tables.o:(.rodata+0x8c): first defined here ../external/out.release/lib/libpcre.a(pcre_tables.o):(.rodata+0xa4): multiple definition of `_pcre_utf8_table3' .objs.release/cx_pcre_tables.o:(.rodata+0xa4): first defined here ../external/out.release/lib/libpcre.a(pcre_tables.o):(.rodata+0xc0): multiple definition of `_pcre_utf8_table4' .objs.release/cx_pcre_tables.o:(.rodata+0xc0): first defined here ../external/out.release/lib/libpcre.a(pcre_tables.o):(.rodata+0x180): multiple definition of `_pcre_utt_names' .objs.release/cx_pcre_tables.o:(.rodata+0x100): first defined here /usr/bin/ld: Warning: size of symbol `_pcre_utt_names' changed from 657 in .objs.release/cx_pcre_tables.o to 740 in ../external/out.release/lib/libpcre.a(pcre_tables.o) ../external/out.release/lib/libpcre.a(pcre_tables.o):(.rodata+0x480): multiple definition of `_pcre_utt' .objs.release/cx_pcre_tables.o:(.rodata+0x3a0): first defined here /usr/bin/ld: Warning: size of symbol `_pcre_utt' changed from 630 in .objs.release/cx_pcre_tables.o to 696 in ../external/out.release/lib/libpcre.a(pcre_tables.o) ../external/out.release/lib/libpcre.a(pcre_tables.o):(.rodata+0x738): multiple definition of `_pcre_utt_size' .objs.release/cx_pcre_tables.o:(.rodata+0x618): first defined here .objs.release/cx_pcre_exec.o: In function `match(doc_byte_iter, unsigned char const*, doc_byte_iter, int, match_data*, unsigned long, eptrblock*, int, unsigned int)': cx_pcre_exec.cpp:(.text+0x1c2a): undefined reference to `_pcre_ord2utf8(int, unsigned char*)' .objs.release/eauibook.o: In function `eAuiNotebook::LoadPerspective(wxString const&)': eauibook.cpp:(.text+0x9ad): undefined reference to `wxTabFrame::SetTabCtrlHeight(int)' .objs.release/PreviewDlg.o: In function `global constructors keyed to _ZN10PreviewDlg13sm_eventTableE': PreviewDlg.cpp:(.text+0x11b2): undefined reference to `wxEVT_WEB_TITLECHANGE' PreviewDlg.cpp:(.text+0x11ee): undefined reference to `wxEVT_WEB_DOMCONTENTLOADED' .objs.release/PreviewDlg.o: In function `PreviewDlg::RefreshBrowser(PreviewDlg::cxUpdateMode)': PreviewDlg.cpp:(.text+0x2a47): undefined reference to `wxWebControl::OpenURI(wxString const&, unsigned int, wxWebPostData*, bool)' .objs.release/PreviewDlg.o: In function `PreviewDlg::OnWebDocumentComplete(wxWebEvent&)': PreviewDlg.cpp:(.text+0x3259): undefined reference to `wxWebControl::GetCurrentURI() const' .objs.release/PreviewDlg.o: In function `PreviewDlg::PreviewDlg(EditorFrame&)': PreviewDlg.cpp:(.text+0x4984): undefined reference to `wxWebControl::IsInitialized()' PreviewDlg.cpp:(.text+0x49c5): undefined reference to `wxWebControl::wxWebControl(wxWindow*, int, wxPoint const&, wxSize const&)' PreviewDlg.cpp:(.text+0x562f): undefined reference to `wxWebControl::InitEngine(wxString const&)' .objs.release/PreviewDlg.o: In function `PreviewDlg::PreviewDlg(EditorFrame&)': PreviewDlg.cpp:(.text+0x68e4): undefined reference to `wxWebControl::IsInitialized()' PreviewDlg.cpp:(.text+0x6925): undefined reference to `wxWebControl::wxWebControl(wxWindow*, int, wxPoint const&, wxSize const&)' PreviewDlg.cpp:(.text+0x758f): undefined reference to `wxWebControl::InitEngine(wxString const&)' .objs.release/PreviewDlg.o: In function `PreviewDlg::OnButtonForward(wxCommandEvent&)': PreviewDlg.cpp:(.text+0x132): undefined reference to `wxWebControl::GoForward()' .objs.release/PreviewDlg.o: In function `PreviewDlg::OnButtonBack(wxCommandEvent&)': PreviewDlg.cpp:(.text+0x182): undefined reference to `wxWebControl::GoBack()' ../ecore/libecore.so(cxInternal.o): In function `cxInternal::MoveOldSettings(eSettings&)': cxInternal.cpp:(.text+0x4d29): undefined reference to `eSettings::SetPageSettings(unsigned int, wxString const&, doc_id, int, int, wxString const&, std::vector<unsigned int, std::allocator<unsigned int> > const&, std::vector<cxBookmark, std::allocator<cxBookmark> > const&, eSettings::SubPage)' collect2: ld returned 1 exit status make: *** [e] Error 1 EDIT: Forgot the link http://github.com/etexteditor/e

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