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• Silverlight - C# and LINQ - Ordering By Multiple Fields

  - by user70192

  Hello, I have an ObservableCollection of Task objects. Each Task has the following properties: AssignedTo Category Title AssignedDate I'm giving the user an interface to select which of these fields they was to sort by. In some cases, a user may want to sort by up to three of these properties. How do I dynamically build a LINQ statement that will allow me to sort by the selected fields in either ascending or descending order? Currently, I'm trying the following, but it appears to only sort by the last sort applied: var sortedTasks = from task in tasks select task; if (userWantsToSortByAssignedTo == true) { if (sortByAssignedToDescending == true) sortedTasks = sortedTasks.OrderByDescending(t => t.AssignedTo); else sortedTasks = sortedTasks.OrderBy(t => t.AssignedTo); } if (userWantsToSortByCategory == true) { if (sortByCategoryDescending == true) sortedTasks = sortedTasks.OrderByDescending(t => t.Category); else sortedTasks = sortedTasks.OrderBy(t => t.Category); } Is there an elegant way to dynamicaly append order clauses to a LINQ statement?

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• PHP Exceptions in Classes

  - by mike condiff

  I'm writing a web application (PHP) for my friend and have decided to use my limited OOP training from Java. My question is what is the best way to note in my class/application that specific critical things failed without actually breaking my page. Currently my problem is I have an Object "SummerCamper" which takes a camper_id as it's argument to load all of the necessary data into the object from the database. Say someone specifies a camper_id in the querystring that does not exist, I pass it to my objects constructor and the load fails. Currently I don't see a way for me to just return false from the constructor. I have read I could possibly do this with Exceptions, throwing an exception if no records are found in the database or if some sort of validation fails on input of the camper_id from the application etc. However, I have not really found a great way to alert my program that the Object Load has failed. I tried returning false from within the CATCH but the Object still persists in my php page. I do understand I could put a variable $is_valid = false if the load fails and then check the Object using a get method but I think there may be better ways. What is the best way of achieving the essential termination of an object if a load fails? Should I load data into the object from outside the constructor? Is there some osrt of design pattern that I should look into? Any help would be appreciated.

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• How to control dojo widget classes, or how to get fine-grained control of style

  - by djna

  I am creating a UI with dojo that is emulting some aspects of an existing thick client application. I need to programatically put two different menu bars on the same page. I have successfully created the two menu bars using new dijit.Menu(); new dijit.MenuItem(); and so on. Now I want to give them slightly different presentation styles. As I'm going to have quite a few pages of this sort my first thought is to use different CSS style classes. And that's the problem: when I create the Menu and it's items we get quite a set of HTML objects, each with CSS classes specified by dojo, and the classes are the same for the items associated with either menu. How can I best get specific control for any one menu? I could determine the dojo-generated ids for each item, and specify styles by ids, but that seems like hard work. Is there an sensible way to control the classes defined by dojo, or a nice CSS way to select only the items associated with one menu bar?

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• d3: Coloring Multiple Lines from Nested Data

  - by diet_coke

  I'm currently assembling some line graphs with circles at the datapoints from arrays of JSON objects formatted like so: var data = [{ "name": "metric1", "datapoints": [ [10.0, 1333519140], [48.0, 1333519200] ] }, { "name": "metric2", "datapoints": [ [48.0, 1333519200], [12.0, 1333519260] ] }] I want to have a color for each metric, so I'm trying to color them based on the index of the object within the array data. The code I have currently for just placing the circles looks like: // We bind an svg group to each metric. var metric_groups = this.vis.selectAll("g.metric_group") .data(data).enter() .append("g") .attr("class", "metric_group"); // Then bind a circle for each datapoint. var circles = metric_groups.selectAll("circle") .data(function(d) { return d.datapoints; }); circles.enter().append("circle") .attr("r", 3.5); Now if I change that last bit to something like: circles.enter().append("circle") .attr("r", 3.5); .style("fill", function(d,i) { return i%2 ? "red" : "blue"; } I get alternating red and blue circles, as could be expected. Taking some advice from Nested Selections : 'Nesting and Index', I tried: circles.enter().append("circle") .attr("r", 3.5); .style("fill", function(d,i,j) { return j%2 ? "red" : "blue"; } Which doesn't work (j is undefined), presumably because we are in the named property datapoints, rather than an array element. How might I go about doing the coloring that I want without changing my data structure? Thanks!

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• movieClip in Array displays null, and aren't showing up on stage.addChild(Array[i])

  - by jtdino

  i am new to Actionscript3, i need to know why i keep getting Parameter child must be non-null. And my code won't display 5 enemyBlock objects onto the stage but only just one. any tips and help will be much appreciated. thanks in advance. returns: TypeError: Error #2007: Parameter child must be non-null. at flash.display::DisplayObjectContainer/addChild() at flash.display::Stage/addChild() at BlockDrop_fla::MainTimeline/EnemyBlockPos() at BlockDrop_fla::MainTimeline/frame2() // declare varibles var isEnemyMoving:Boolean = false; var enemyArray:Array; var enemyBlock:MovieClip = new EnemyBlock(); // assign EnemyBlock class to enemyBlock var enemyBlockMC:MovieClip; var count:int = 5; var mapWidth:Number = 800; var mapHeight:Number = 600; function EnemyBlockPos() :void { // assign new MovieClip not null enemyBlockMC = new MovieClip; enemyArray = new Array(); for(var i=1; i<= count; i++){ // add class to MC enemyBlockMC.addChild(enemyBlock); // randomize position enemyBlock.x = Math.round(Math.random()*mapWidth); enemyBlock.y = Math.round(Math.random()*mapHeight); // set motion enemyBlock.movement = 5; // add MC to array enemyArray.push(enemyBlockMC); } for (var w = 1; w <= enemyArray.length; w++) { addChild(enemyArray[w]); } } // endOf EnemyBlockPos

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• Implicit Type Conversions in Reflection

  - by bradhe

  So I've written a quick bit of code to help quickly convert between business objects and view models. Not to pimp my own blog, but you can find the details here if you're interested or need to know. One issue I've run in to is that I have a custom collection type, ProductCollection, and I need to turn that in to a string[] in on my model. Obviously, since there is no default implicit cast, I'm getting an exception in my contract converter. So, I thought I would write the next little bit of code and that should solve the problem: public static implicit operator string[](ProductCollection collection) { var list = new List<string>(); foreach (var product in collection) { if (product.Id == null) { list.Add(null); } else { list.Add(product.Id.ToString()); } } return list.ToArray(); } However, it still fails with the same cast exception. I'm wondering if it has something to do with being in reflection? If so, is there anything that I can do here?? I'm open to architectural solutions, too!

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• Is this a good decorator pattern for javascript?

  - by Kucebe

  I need some simple objects that could become more complex later, with many different properties, so i thought to decorator pattern. I made this looking at Crockford's power constructor and object augmentation: //add property to object Object.prototype.addProperty = function(name, func){ for(propertyName in this){ if(propertyName == name){ throw new Error(propertyName + " is already defined"); } } this[name] = func; }; //constructor of base object var BaseConstructor = function(param){ var _privateVar = param; return{ getPrivateVar: function(){ return _privateVar; } }; }; //a simple decorator, adds one private attribute and one privileged method var simpleDecorator = function(obj, param){ var _privateVar = param; var privilegedMethod1 = function(){ return "privateVar of decorator is: " + _privateVar; }; obj.addProperty("privilegedMethod1", privilegedMethod1); return obj; } //a more complex decorator, adds public and private properties var complexDecorator = function(obj, param1, param2){ //private properties var _privateVar = param1; var _privateMethod = function(x){ for(var i=0; i<x; i++){ _privateVar += x; } return _privateVar; }; //public properties var publicVar = "I'm public"; obj.addProperty("publicVar", publicVar); var privilegedMethod2 = function(){ return _privateMethod(param2); }; obj.addProperty("privilegedMethod2", privilegedMethod2); var publicMethod = function(){ var temp = this.privilegedMethod2(); return "do something: " + temp + " - publicVar is: " + this.publicVar; }; obj.addProperty("publicMethod", publicMethod); return obj; } //new basic object var myObj = BaseConstructor("obj1"); //the basic object will be decorated var myObj = simpleDecorator(obj, "aParam"); //the basic object will be decorated with other properties var myObj = complexDecorator(obj, 2, 3); Is this a good way to have Decorator Pattern in javascript? Are there other better ways to do this?

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• Center label instance inside VGroup in Flex

  - by Jerry

  Hi all I am trying to center my labels below my image inside my VGroup. The labels are align to left now and it seems like HorizontalAlign is not working on spark component. Anyone knows how to fix it? Thanks a lot. <?xml version="1.0" encoding="utf-8"?> <s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600"> <fx:Declarations> <!-- Place non-visual elements (e.g., services, value objects) here --> </fx:Declarations> <s:VGroup width="800"> <mx:Image source="images/big/city1.jpg"/> <s:Label text="test1" horizontalCenter="0" /> //doesn't work....:( <s:Label text="test2" /> </s:VGroup> </s:Application>

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• CORBA on MacOS X (Cocoa)

  - by user8472

  I am currently looking into different ways to support distributed model objects (i.e., a computational model that runs on several different computers) in a project that initially focuses on MacOS X (using Cocoa). As far as I know there is the possibility to use the class cluster around NSProxy. But there also seem to be implementations of CORBA around with Objective-C support. At a later time there may be the need to also support/include Windows machines. In that case I would need to use something like Gnustep on the Windows side (which may be an option, if it works well) or come up with a combination of both technologies. Or write something manually (which is, of course, the least desirable option). My questions are: If you have experience with both technologies (Cocoa native infrastructure vs. CORBA) can you point out some key features/issues of either approach? Is it possible to use Gnustep with Cocoa in the way explained above? Is it possible (and reasonably feasible, i.e. simpler than writing a network layer manually) to communicate among all MacOS clients using Cocoa's technology and with Windows clients through CORBA?

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• problem adding object to hashtable

  - by daemonkid

  I am trying to call a class method dynamically depending on a condition. This is how I am doing it I have three classes implement a single interface interface IReadFile { string DoStuff(); } The three classes A,B,C implement the interface above. I am trying to add them to a hashtable with the code below _HashT.Add("a", new classA()); _HashT.Add("b", new classB()); _HashT.Add("c", new classC()); This compiles fine, but gives a runtime error.{Object reference not set to an instance of an object.} I was planning to return the correct class to the interface type depending on a parameter that matches the key value. say if I send in a. ClassA is returned to the interface type and the method is called. IReadFile Obj = (IReadFile )_HashT["a"].GetType(); obj.DoStuff(); How do I correct the part above where the objects need to be added to the hashtable? Or do I need to use a different approach? All the classes are in the same assembly and namespace. Thanks for your time.

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• In a class with no virtual methods or superclass, is it safe to assume (address of first member vari

  - by Jeremy Friesner

  Hi all, I made a private API that assumes that the address of the first member-object in the class will be the same as the class's this-pointer... that way the member-object can trivially derive a pointer to the object that it is a member of, without having to store a pointer explicitly. Given that I am willing to make sure that the container class won't inherit from any superclass, won't have any virtual methods, and that the member-object that does this trick will be the first member object declared, will that assumption hold valid for any C++ compiler, or do I need to use the offsetof() operator (or similar) to guarantee correctness? To put it another way, the code below does what I expect under g++, but will it work everywhere? class MyContainer { public: MyContainer() {} ~MyContainer() {} // non-virtual dtor private: class MyContained { public: MyContained() {} ~MyContained() {} // Given that the only place Contained objects are declared is m_contained // (below), will this work as expected on any C++ compiler? MyContainer * GetPointerToMyContainer() { return reinterpret_cast<MyContainer *>(this); } }; MyContained m_contained; // MUST BE FIRST MEMBER ITEM DECLARED IN MyContainer int m_foo; // other member items may be declared after m_contained float m_bar; };

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• How do I make JPA POJO classes + Netbeans forms play well together?

  - by Zak

  I started using netbeans to design forms to edit the instances of various classes I have made in a small app I am writing. Basically, the app starts, an initial set of objects is selected from the DB and presented in a list, then an item in the list can be selected for editing. When the editor comes up it has form fields for many of the data fields in the class. The problem I run into is that I have to create a controller that maps each of the data elements to the correct form element, and create an inordinate number of small conversion mapping lines of code to convert numbers into strings and set the correct element in a dropdown, then another inordinate amount of code to go back and update the underlying object with all the values from the form when the save button is clicked. My question is; is there a more directly way to make the editing of the form directly modify the contents of my class instance? I would like to be able to have a default mapping "controller" that I can configure, then override the getter/setter for a particular field if needed. Ideally, there would be standard field validation for things like phone numbers, integers, floats, zip codes, etc... I'm not averse to writing this myself, I would just like to see if it is already out there and use the right tool for the right job.

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• Execute a function to affect different template class instances

  - by Samer Afach

  I have a complicated problem, and I need help. I have a base case, class ParamBase { string paramValue; //... } and a bunch of class templates with different template parameters. template <typename T> class Param : public ParamBase { T value; //... } Now, each instance of Param has different template parameter, double, int, string... etc. To make it easier, I have a vector to their base class pointers that contains all the instances that have been created: vector<ParamBase*> allParamsObjects; The question is: How can I run a single function (global or member or anything, your choice), that converts all of those different instances' strings paramValue with different templates arguments and save the conversion result to the appropriate type in Param::value. This has to be run over all objects that are saved in the vector allParamsObjects. So if the template argument of the first Param is double, paramValue has to be converted to double and saved in value; and if the second Param's argument is int, then the paramValue of the second has to be converted to int and saved in value... etc. I feel it's almost impossible... Any help would be highly appreciated :-)

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• How to get a template tag to auto-check a checkbox in Django

  - by Daniel Quinn

  I'm using a ModelForm class to generate a bunch of checkboxes for a ManyToManyField but I've run into one problem: while the default behaviour automatically checks the appropriate boxes (when I'm editing an object), I can't figure out how to get that information in my own custom templatetag. Here's what I've got in my model: ... from django.forms import CheckboxSelectMultiple, ModelMultipleChoiceField interests = ModelMultipleChoiceField(widget=CheckboxSelectMultiple(), queryset=Interest.objects.all(), required=False) ... And here's my templatetag: @register.filter def alignboxes(boxes, cls): """ Details on how this works can be found here: http://docs.djangoproject.com/en/1.1/howto/custom-template-tags/ """ r = "" i = 0 for box in boxes.field.choices.queryset: r += "<label for=\"id_%s_%d\" class=\"%s\"><input type=\"checkbox\" name=\"%s\" value=\"%s\" id=\"id_%s_%d\" /> %s</label>\n" % ( boxes.name, i, cls, boxes.name, box.id, boxes.name, i, box.name ) i = i + 1 return mark_safe(r) The thing is, I'm only doing this so I can wrap some simpler markup around these boxes, so if someone knows how to make that happen in an easier way, I'm all ears. I'd be happy with knowing a way to access whether or not a box should be checked though.

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• Hibernate collection multiple types

  - by CaptainAwesomePants

  I have a class Player that contains a list of Accessory objects. There are two kinds of Accessories. SocketedAccessories have a list of SocketJewels, and MagicAccessories have a list of MagicEnchantments. At the database level, there is a players table that represents the player, and an accessories table that contains a list of accessories. Accessories have a type field that indicates whether they are socketed or magical, and the columns that are only used by one type are just left blank by entries of the other type. There are socket_jewels and magic_enchantments tables, representing the socket jewels or the magic enchantments on each accessory. I am trying to figure out the correct way to map this with Hibernate. One way would be for the player to have two lists of accessories, one for SocketedAccessories and one for MagicAccessories. That seems undesirable, though. What I want is a way to specify that player should have a field List<Accessory> accessories that contains both types of thing. Is there a way to tell Hibernate, in either hbm.xml or annotations, to do this?

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• Populate a tree from Hierarchical data using 1 LINQ statement

  - by Midhat

  Hi. I have set up this programming exercise. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication2 { class DataObject { public int ID { get; set; } public int ParentID { get; set; } public string Data { get; set; } public DataObject(int id, int pid, string data) { this.ID = id; this.ParentID = pid; this.Data = data; } } class TreeNode { public DataObject Data {get;set;} public List<DataObject> Children { get; set; } } class Program { static void Main(string[] args) { List<DataObject> data = new List<DataObject>(); data.Add(new DataObject(1, 0, "Item 1")); data.Add(new DataObject(2, 0, "Item 2")); data.Add(new DataObject(21, 2, "Item 2.1")); data.Add(new DataObject(22, 2, "Item 2.2")); data.Add(new DataObject(221, 22, "Item 2.2.1")); data.Add(new DataObject(3, 0, "Item 3")); } } } The desired output is a List of 3 treenodes, having items 1, 2 and 3. Item 2 will have a list of 2 dataobjects as its children member and so on. I have been trying to populate this tree (or rather a forest) using just 1 SLOC using LINQ. A simple group by gives me the desired data but the challenge is to organize it in TreeNode objects. Can someone give a hint or an impossibility result for this?

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• How can I execute an ANTLR parser action for each item in a rule that can match more than one item?

  - by Chris Farmer

  I am trying to write an ANTLR parser rule that matches a list of things, and I want to write a parser action that can deal with each item in the list independently. Some example input for these rules is: $(A1 A2 A3) I'd like this to result in an evaluator that contains a list of three MyIdentEvaluator objects -- one for each of A1, A2, and A3. Here's a snippet of my grammar: my_list returns [IEvaluator e] : { $e = new MyListEvaluator(); } '$' LPAREN op=my_ident+ { /* want to do something here for each 'my_ident'. */ /* the following seems to see only the 'A3' my_ident */ $e.Add($op.e); } RPAREN ; my_ident returns [IEvaluator e] : IDENT { $e = new MyIdentEvaluator($IDENT.text); } ; I think my_ident is defined correctly, because I can see the three MyIdentEvaluators getting created as expected for my input string, but only the last my_ident ever gets added to the list (A3 in my example input). How can I best treat each of these elements independently, either through a grammar change or a parser action change? It also occurred to me that my vocabulary for these concepts is not what it should be, so if it looks like I'm misusing a term, I probably am. EDIT in response to Wayne's comment: I tried to use op+=my_ident+. In that case, the $op in my action becomes an IList (in C#) that contains Antlr.Runtime.Tree.CommonTree instances. It does give me one entry per matched token in $op, so I see my three matches, but I don't have the MyIdentEvaluator instances that I really want. I was hoping I could then find a rule attribute in the ANTLR docs that might help with this, but nothing seemed to help me get rid of this IList. Result... Based on chollida's answer, I ended up with this which works well: my_list returns [IEvaluator e] : { $e = new MyListEvaluator(); } '$' LPAREN (op=my_ident { $e.Add($op.e); } )+ RPAREN ; The Add method gets called for each match of my_ident.

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• Problems breaking out of nested loops

  - by user1040281

  I have problems breaking out off these nested loops correctly. What the code is trying to do is to indicate that a customer has rented a certain movie. Both the movie and customer are compared to properties of arraylist objects and then if all checks out the name property and ID property of a movie object are added as a string to another arraylist. All this works correctly as long as I use the first movie (from movies) and the first customer (from customers) but if I try renting other movies further down my arraylist with other customers then it adds the rented movie to the customerRentedMovies arraylist but prints out the "else message". I figure I need to break out of the foreach(blabla) loops aswell? or could goto be used? Comments was removed (looked kinda messy, can explain further if needed) public void RentMovie(string titel, int movieID, string name, int customerID) { foreach (Customer customer in customers) { if (name == customer.Name && customerID == customer.CustomerID) { foreach (MovieInfo movie in movies) { if (titel == movie.Titel && movieID == movie.MovieID) { movie.rented = true; string rentedMovie = string.Format("{0} ID: {1}", movie.Titel, movie.MovieID); customer.customerRentedMovies.Add(rentedMovie); break; } else { Console.WriteLine("No movie with that titel and ID!"); } } break; } else { Console.WriteLine("No customer with that ID and name"); } } }

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• How do I make custom functions chain-able with jQuery's?

  - by sergio

  I need a "callfront" or "precall" (the opposite of "callback" ¿?) to add in MANY places before an animation occurs in an existing plugin, To be used like e.g. $(some_unpredictable_obj).preFunct().animate(… The problem is, as I said they are MANY places, and all of them are different animations, on different objects. I can TELL where all of them occur, but I don't want to add over and over the same code. I actually have to add both a function before and after those animations, but I think I can use the callback for all of them. In a perfect world, I'd like to replace every animate(property, duration) by preFunct().animate(property,duration).postFunct() preFunct and postFunct don't need parameters, since they are always the same action, on the same object. This could be an amazing addition to "jQuery" (an easy way to jQuerize custom functions to be added to the normal chain (without messing with queues) I found this example but it will act on the applied element, and I don't want that because, as I said above, all the original animations to be added to are on different elements. I also found jQuery.timing, but it looks cooler the chain-able function :) Thanks.

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• How to fix error - "@interface interfaceName : someEnumeration" gives error "cannot find interface '

  - by Paul V

  How can I solve "cannot find interface declaration 'someEnumeration', superclass of 'interfaceName'" error? What steps will reproduce the problem? Compiling Wsdl2ObjC Targeting groupwise.wsdl file Fixing non-valid file names of output csource code like ".h" + ".m" and objects inside source files Moving up one of the @interface BEFORE it was used futher in code! What is the expected output? Something working What do you see instead? 33 errors. "Inherited" from only 3 similar Inheritances of a typedef enum object by a class. All errors are typical: typedef enum types_StatusTrackingOptions { types_StatusTrackingOptions_none = 0, types_StatusTrackingOptions_None, types_StatusTrackingOptions_Delivered, types_StatusTrackingOptions_DeliveredAndOpened, types_StatusTrackingOptions_All, } types_StatusTrackingOptions; types_StatusTrackingOptions types_StatusTrackingOptions_enumFromString(NSString *string); NSString * types_StatusTrackingOptions_stringFromEnum(types_StatusTrackingOptions enumValue); @interface types_StatusTracking : types_StatusTrackingOptions { ... and here I'm having error "cannot find interface declaration for 'types_StatusTrackingOptions', superclass of 'types_StatusTracking'". What version of the product are you using? On what operating system? Wsdl2ObjC - rev 168, OS - Mac OS X 10.6.2, iPhone SDK - 3.2, Simulator - v. 3.1.2 - 3.1.3, wsdl - for GroupWise v.8, NDK released 2008-12-23, wsdl and xsd files are attached. P.S. GroupWise.wsdl + .xsd files could be downloaded from http://code.google.com/p/wsdl2objc/issues/detail?id=99

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• How is it possible to extend an SWFLoader with MXML?

  - by michael-cereda

  I'm currently doing the following.. Main application: " " In the Component: First Try: ]]> </fx:Script> <fx:Declarations></fx:Declarations> <mx:SWFLoader x="0" y="0" id="loader"/> </s:Group> Second Try: <?xml version="1.0" encoding="utf-8"?> <s:Group xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx"> <fx:Script> <![CDATA[ [Bindable] public var source:String; ]]> </fx:Script> <fx:Declarations> <!-- Place non-visual elements (e.g., services, value objects) here --> </fx:Declarations> <mx:SWFLoader x="0" y="0" source="{source}"/> </s:Group> But the component displays only a "Not Found" icon in both cases. Thanks

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• Java - How to declare table[i][j] elements as instance variables?

  - by JDelage

  All, I am trying to code a Connect4 game. For this, I have created a P4Game class and a P4Board class which represents the i X j dimensions of the Connect4 board. In P4Game, I have the following: public class P4Game{ //INSTANCE VARIABLES private int nbLines; private int nbColumns; private P4Board [][] position; //CONSTRUCTOR public P4Game(int nbLines, int nbColumns){ this.nbColumns = nbColumns; this.nbLines = nbLines; P4Board [][] position = new P4Board [nbLines][nbColumns]; //Creates the table to receive the instances of the P4Board object.*/ for (int i=0; i<nbLines; i++){ for (int j=0; j<nbColumns; j++){ this.position[i][j] = new P4Board(i,j); //Meant to create each object at (line=i, column=j) } } } This causes a NullPointerException in the nested loops where I mention this.position[i][j]. I reference those objects in other methods of this class so I need them to be instance variables. I suppose the exception is due to the fact that I have not listed the table element position[i][j] as an instance variable at the beginning of the class. my question to people here is (1) is my assumption correct, and if so (2) what would be the syntax to declare instance variables of this form? Thank you all for your help with what I realize is a very basic question. Hopefully it will also benefit other newbies. Cheers, JDelage

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• How should I pass the translated text to my object in my multilingual application?

  - by boatingcow

  Up until now, I have maintained a 'dictionary' table in my database, for example: +-----------+---------------------------------------+-----------------------------------------------+--------+ | phrase | en | fr | etc... | +-----------+---------------------------------------+-----------------------------------------------+--------+ | generated | Generated in %1$01.2f seconds at %2$s | Créée en %1$01.2f secondes à %2$s aujourd'hui | ... | | submit | Submit... | Envoyer... | ... | +-----------+---------------------------------------+-----------------------------------------------+--------+ I'll then select all rows from the database for the column that matches the locale we're interested in (or read the cache from a file to speed db lookup) and dump the dictionary into an array called $lng. Then I'll have HTML helper objects like this in my view: $html->input(array('type' => 'submit', 'value' => $lng['submit'], etc...)); ... $html->div(array('value' => sprintf($lng['generated'], $generated, date('H:i')), etc...)); The translations can appear in PDF, XLS and AJAX responses too. The problem with my approach so far is that I now have loads of global $lng; in every class where there is a function that spits out UI code.. How do other people get the translation into the object? Is it one scenario where globals aren't actually that bad? Would it be madness to create a class with accessors when the dictionary terms are all static?

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• Abstract base class puzzle

  - by 0x80

  In my class design I ran into the following problem: class MyData { int foo; }; class AbstraktA { public: virtual void A() = 0; }; class AbstraktB : public AbstraktA { public: virtual void B() = 0; }; template<class T> class ImplA : public AbstraktA { public: void A(){ cout << "ImplA A()"; } }; class ImplB : public ImplA<MyData>, public AbstraktB { public: void B(){ cout << "ImplB B()"; } }; void TestAbstrakt() { AbstraktB *b = (AbstraktB *) new ImplB; b->A(); b->B(); }; The problem with the code above is that the compiler will complain that AbstraktA::A() is not defined. Interface A is shared by multiple objects. But the implementation of A is dependent on the template argument. Interface B is the seen by the outside world, and needs to be abstrakt. The reason I would like this is that it would allow me to define object C like this: Define the interface C inheriting from abstrakt A. Define the implementation of C using a different datatype for template A. I hope I'm clear. Is there any way to do this, or do I need to rethink my design?

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• Trying to make a plugin system in C++/Qt

  - by Pirate for Profit

  I'm making a task-based program that needs to have plugins. Tasks need to have properties which can be easily edited, I think this can be done with Qt's Meta-Object Compiler reflection capabilities (I could be wrong, but I should be able to stick this in a QtPropertyBrowser?) So here's the base: class Task : public QObject { Q_OBJECT public: explicit Task(QObject *parent = 0) : QObject(parent){} virtual void run() = 0; signals: void taskFinished(bool success = true); } Then a plugin might have this task: class PrinterTask : public Task { Q_OBJECT public: explicit PrinterTask(QObject *parent = 0) : Task(parent) {} void run() { Printer::getInstance()->Print(this->getData()); // fictional emit taskFinished(true); } inline const QString &getData() const; inline void setData(QString data); Q_PROPERTY(QString data READ getData WRITE setData) // for reflection } In a nutshell, here's what I want to do: // load plugin // find all the Tasks interface implementations in it // have user able to choose a Task and edit its specific Q_PROPERTY's // run the TASK It's important that one .dll has multiple tasks, because I want them to be associated by their module. For instance, "FileTasks.dll" could have tasks for deleting files, making files, etc. The only problem with Qt's plugin setup is I want to store X amount of Tasks in one .dll module. As far as I can tell, you can only load one interface per plugin (I could be wrong?). If so, the only possible way to do accomplish what I want is to create a FactoryInterface with string based keys which return the objects (as in Qt's Plug-And-Paint example), which is a terrible boilerplate that I would like to avoid. Anyone know a cleaner C++ plugin architecture than Qt's to do what I want? Also, am I safely assuming Qt's reflection capabilities will do what I want (i.e. able to edit an unknown dynamically loaded tasks' properties with the QtPropertyBrowser before dispatching)?

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