Search Results

Search found 45348 results on 1814 pages for 'immutable class'.

Page 399/1814 | < Previous Page | 395 396 397 398 399 400 401 402 403 404 405 406  | Next Page >

  • CQRS - Should a Command try to create a "complex" master-detail entity?

    - by Simon Crabtree
    I've been reading Greg Young and Udi Dahan's thoughts on Command Query Responsibilty Separation and a lot of what I read strikes a chord with me. My domain (we track vehicles which are doing deliveries) has the concept of a Route which contains one or more Stops. I need my customers to be able to set these up in our system by calling a webservice, and then be able to retrieve information about a Route and how the vehicle is progressing. In the past I would have "cut-down" DTO classes which closely resemble my domain classes, and the customer would create a RouteDto with an array of StopDto(s), and call our CreateRoute webmethod, passing in the RouteDto. When they query our system by calling the GetRouteDetails method, I would return exactly the same objects to them. One of the appealing aspects of CQRS is that the RouteDto might have all manner of properties that the customer wants to query, but have no business setting when they create a Route. So I create a separate CreateRouteRequest class which is passed in when calling the CreateRoute "command", and a Route DTO class which gets returned as a query result. class Route{ string Reference; List<Stop> Stops; } But I need my customer to provide me with Route AND Stop details when they create a route. As I see it I could either... Give my CreateRouteRequest class a Stops(s) property which is an array of "something" representing the data they need to provide about each stop - but what do I call this class? It's not a Stop as that's what I'm calling the list of DTO inside my Route DTO, but I don't like "CreateStopRequest". I also wonder if I'm stuck in a CRUD mindset here thinking in terms of master-detail information and asking the customer to think like that too. class CreateRouteRequest{ string Reference; ... List<CreateStopRequest> Stops; } or They call CreateRoute, and then make a number of calls to an AddStopToRoute method. This feels a bit more "behavioural" but I'm going to lose the ability to treat creating a route including its stops as a single atomic command. If they create a Route and then try to add a Stop which fails due to some validation problem they're going to have a partially correct Route. The fact that I can't come up with a good name for the list of "StopCreationData" objects I'd be working with in option 1, makes me wonder if there's something I'm missing.

    Read the article

  • Does anyone use AMPL anymore

    - by steven
    I took a class on "Intelligent Decision Making" (which was mostly an Problem Optimization class). In the class we learned about AMPL and how to extend the solvers. I haven't heard much about it lately, nor have I seen job listings for it. My question is: Is AMPL still in use anymore? If so what is it being used for? Yes, I do understand that AMPL can be replaced with Matlab, however AMPL is free and Matlab isn't even close.

    Read the article

  • BigDecimal to_s does not match to_f

    - by Chris Bisignani
    Is the BigDecimal class broken? It seems like the following should never, ever occur: Note that a.to_f != a.to_s.to_f a.class = BigDecimal a.to_f = 18658.1072928 a.to_s = "10865.81072928" b.class = BigDecimal b.to_f = 10000.0 b.to_s = "10000.0" (a - b).to_f = 865.81072928 a.to_f - b.to_f = 8658.1072928 Any ideas as to what might be going wrong?

    Read the article

  • Extension methods for encapsulation and reusability

    - by tzaman
    In C++ programming, it's generally considered good practice to "prefer non-member non-friend functions" instead of instance methods. This has been recommended by Scott Meyers in this classic Dr. Dobbs article, and repeated by Herb Sutter and Andrei Alexandrescu in C++ Coding Standards (item 44); the general argument being that if a function can do its job solely by relying on the public interface exposed by the class, it actually increases encapsulation to have it be external. While this confuses the "packaging" of the class to some extent, the benefits are generally considered worth it. Now, ever since I've started programming in C#, I've had a feeling that here is the ultimate expression of the concept that they're trying to achieve with "non-member, non-friend functions that are part of a class interface". C# adds two crucial components to the mix - the first being interfaces, and the second extension methods: Interfaces allow a class to formally specify their public contract, the methods and properties that they're exposing to the world. Any other class can choose to implement the same interface and fulfill that same contract. Extension methods can be defined on an interface, providing any functionality that can be implemented via the interface to all implementers automatically. And best of all, because of the "instance syntax" sugar and IDE support, they can be called the same way as any other instance method, eliminating the cognitive overhead! So you get the encapsulation benefits of "non-member, non-friend" functions with the convenience of members. Seems like the best of both worlds to me; the .NET library itself providing a shining example in LINQ. However, everywhere I look I see people warning against extension method overuse; even the MSDN page itself states: In general, we recommend that you implement extension methods sparingly and only when you have to. So what's the verdict? Are extension methods the acme of encapsulation and code reuse, or am I just deluding myself?

    Read the article

  • Using FindAll on a List<List<T>> type

    - by Ken Foster
    Assuming public class MyClass { public int ID {get; set; } public string Name {get; set; } } and List<MyClass> classList = //populate with MyClass instances of various IDs I can do List<MyClass> result = classList.FindAll(class => class.ID == 123); and that will give me a list of just classes with ID = 123. Works great, looks elegant. Now, if I had List<List<MyClass>> listOfClassLists = //populate with Lists of MyClass instances How do I get a filtered list where the lists themselves are filtered. I tried List<List<MyClass>> result = listOfClassLists.FindAll (list => list.FindAll(class => class.ID == 123).Count > 0); it looks elegant, but doesn't work. It only includes Lists of classes where at least one class has an ID of 123, but it includes ALL MyClass instances in that list, not just the ones that match. I ended up having to do List<List<MyClass>> result = Results(listOfClassLists, 123); private List<List<MyClass>> Results(List<List<MyClass>> myListOfLists, int id) { List<List<MyClass>> results = new List<List<MyClass>>(); foreach (List<MyClass> myClassList in myListOfLists) { List<MyClass> subList = myClassList.FindAll(myClass => myClass.ID == id); if (subList.Count > 0) results.Add(subList); } return results; } which gets the job done, but isn't that elegant. Just looking for better ways to do a FindAll on a List of Lists. Ken

    Read the article

  • C# myths about best practices?

    - by TheMachineCharmer
    My colleague keeps telling me of the things listed in comments. I am confused. Can somebody please demystify these things for me? class Bar { private int _a; public int A { get { return _a; } set { _a = value; } } private Foo _objfoo; public Foo OFoo { get { return _objfoo; } set { _objfoo = value; } } public Bar(int a, Foo foo) { // this is a bad idea A = a; OFoo = foo; } // MYTHS private void Method() { this.A //1 - this._a //2 - use this when inside the class e.g. if(this._a == 2) A //3 - use this outside the class e.g. barObj.A _a //4 - // Not using this.xxx creates threading issues. } } class Foo { // implementation }

    Read the article

  • jquery tablesorter problem in FF only - header row disappears after show-hide of rows

    - by dac
    When the page loads, all the records show. Sorting works great until show-hide is used to filter the rows so only some show. Then the header row--with the arrows for sorting--DISAPPEARS. The problem is only in Firefox. It works great in IE7 and IE8. I'm using jQuery 1.4.2 from google. Code for show-hide $(document).ready(function() { // show all the rows $("#org_status tr").show(); //find selected filter $("#filter_status a").click(function(evt) { evt.preventDefault(); $("#org_status tr").hide(); var id = $(this).attr('id'); $("." + id).show(); }); }); Here is the HTML: <!-- show-hide "buttons" --> <p id='filter_status'>Filter by status: <a href='#' id='All'>All</a> <a href='#' id='Active'>Active</a> <a href='#' id='Inactive'>Inactive</a> <a href='#' id='Pending'>Pending</a> </p> <!-- table to sort -> <table id='org_status' class='info_table tablesorter'> <thead> <tr> <th class='org-name-col'>Name</th> <th class='org-status-col'>Status</th> </tr> </thead> <tbody> <tr class='All Active'> <td><a href='admin/org_edit.php?org=29'>Foo Net</a></td> <td>Active</td>"; </tr> <tr class='All Inactive'> <td><a href='admin/org_edit.php?org=22'>Bar</a></td> <td>Active</td>"; </tr> <tr class='All Pending'> <td><a href='admin/org_edit.php?org=11'> Bar Foo Very Long Org Name Goes Here</a></td> <td>Active</td>"; </tr> </tbody> </table>

    Read the article

  • Can't resolve CalledFromWrongThreadException with Handler

    - by michel
    I will try to keep it simple: In my main activity I make a handler: public class ARViewer extends ARDisplayActivity { public final MHandler mHandler = new MHandler(this); public void onCreate(Bundle savedInstanceState) { ... The class MHandler: public final class MHandler extends Handler{ //main activity private ARViewer arnv; public MHandler(ARViewer arnv){ this.arnv = arnv; } @Override public void handleMessage(Message msg) { ... case H_RR : arnv.setContentView(R.layout.routeplanner); break; ... super.handleMessage(msg); } } But if I call the handleMessage method from a callback function in a other Class, definitely from a other thread, I still get the exception message: CalledFromWrongThreadException (Only the original thread that created a view hierarchy can touch its views) : public void rFound(Route route) { Message msg = new Message(); msg.what = MHandler.H_RR; ARViewer.arnv.mHandler.handleMessage(msg); }

    Read the article

  • Java multi Generic collection parameters complie error

    - by Geln Yang
    Hi, So strange!Please have a look the code first: public class A { } public class B extends A { } public class C extends A { } public class TestMain { public <T extends A> void test(T a, T b) { } public <T extends A> void test(List<T> a, List<T> b) { } public static void main(String[] args) { new TestMain().test(new B(), new C()); new TestMain().test(new ArrayList<B>(), new ArrayList<C>()); } } The statement "new TestMain().test(new ArrayList(), new ArrayList())" get a "Bound mismatch" compile error, while "new TestMain().test(new B(), new C())" is compiled ok. Bound mismatch: The generic method test(T, T) of type TestMain is not applicable for the arguments (ArrayList, ArrayList). The inferred type ArrayList is not a valid substitute for the bounded parameter It seems the type of the second generic List parameter is limited by the Type of the first.Is it a feature or a bug of the compile program? ps, jdk:1.6,IDE:Eclipse 3.5.1

    Read the article

  • How to read Windows.UI.XAML.Style properties in C#

    - by Igor Kulman
    I am writing a class that will convert a HTML document to a list of Paragrpahs that can be used with RichTextBlock in Windows 8 apps. I want to be able to give the class a list of Styles defined in XAML and the class will read useful properties from the style and apply them. If I have a Windows.UI.XAML.Style style how do I read a property from it? I tried var fontWeight = style.GetValue(TextElement.FontWeightProperty) for a style defined in XAML with TargetProperty="TextBlock" but this fails with and exception

    Read the article

  • Resolve php "deadlock"

    - by Matt
    Hey all, I'm currently running into a situation that I guess would be called deadlock. I'm implementing a message service that calls various object methods.. it's quite similar to observer pattern.. Here's whats going on: Dispatcher.php Dispatcher.php <? class Dispatcher { ... public function message($name, $method) { // Find the object based on the name $object = $this->findObjectByName($name); // Slight psuedocode.. for ease of example if($this->not_initialized($object)) $object = new $object(); // This is where it locks up. } return $object->$method(); ... } class A { function __construct() { $Dispatcher->message("B", "getName"); } public function getName() { return "Class A"; } } class B { function __construct() { // Assume $Dispatcher is the classes $Dispatcher->message("A", "getName"); } public function getName() { return "Class B"; } } ?> It locks up when neither object is initialized. It just goes back and forth from message each other and no one can be initialized. Any help would be immensely helpful.. Thanks! Matt Mueller

    Read the article

  • integrating recaptcha (with custom look) with asp.net

    - by raklos
    Im using asp.net/c# weborms. I've added recaptcha to the form and used what is on their site. It needs a custom look hence it's like this: <div id="recaptcha_widget" style="display:none"> <div id="recaptcha_image"></div> <div class="recaptcha_only_if_incorrect_sol" style="color:red">Incorrect please try again</div> <span class="recaptcha_only_if_image">Enter the words above:</span> <span class="recaptcha_only_if_audio">Enter the numbers you hear:</span> <input type="text" id="recaptcha_response_field" name="recaptcha_response_field" /> <div><a href="javascript:Recaptcha.reload()">Get another CAPTCHA</a></div> <div class="recaptcha_only_if_image"><a href="javascript:Recaptcha.switch_type('audio')">Get an audio CAPTCHA</a></div> <div class="recaptcha_only_if_audio"><a href="javascript:Recaptcha.switch_type('image')">Get an image CAPTCHA</a></div> <div><a href="javascript:Recaptcha.showhelp()">Help</a></div> </div> <script type="text/javascript" src="http://api.recaptcha.net/challenge?k=your_public_key"> </script> <noscript> <iframe src="http://api.recaptcha.net/noscript?k=your_public_key" height="300" width="500" frameborder="0"></iframe><br> <textarea name="recaptcha_challenge_field" rows="3" cols="40"> </textarea> <input type="hidden" name="recaptcha_response_field" value="manual_challenge"> </noscript> what do i need to do in the button_click method in the code behind iof the form to check if the words eneterd by the user is correct. same for audio. Thanks

    Read the article

  • Hibernate @DiscriminatorColumn and @DiscriminatorValue issue

    - by user224270
    I have this parent class: @Entity @Inheritance(strategy = InheritanceType.JOINED) @Table(name = "BSEntity") @DiscriminatorColumn(name = "resourceType", discriminatorType = DiscriminatorType.STRING, length = 32) public abstract class BaseEntity { and the subclass @Entity @Table(name = "BSCategory") @DiscriminatorValue("Category") public class CategoryEntity extends BaseEntity { But when I run the program, I get the following error: 2010-06-03 10:13:54,222 [main] WARN (org.hibernate.util.JDBCExceptionReporter:100) - SQL Error: 1364, SQLState: HY000 2010-06-03 10:13:54,222 [main] ERROR (org.hibernate.util.JDBCExceptionReporter:101) - Field 'resourceType' doesn't have a default value Any thoughts? Updated: Database is MySQL. I have also changed inheritance strategy to JOINED instead of SINGLE_TABLE. Help

    Read the article

  • Better to use constructor or method factory pattern?

    - by devoured elysium
    I have a wrapper class for the Bitmap .NET class called BitmapZone. Assuming we have a WIDTH x HEIGHT bitmap picture, this wrapper class should serve the purpose of allowing me to send to other methods/classes itself instead of the original bitmap. I can then better control what the user is or not allowed to do with the picture (and I don't have to copy the bitmap lots of times to send for each method/class). My question is: knowing that all BitmapZone's are created from a Bitmap, what do you find preferrable? Constructor syntax: something like BitmapZone bitmapZone = new BitmapZone(originalBitmap, x, y, width, height); Factory Method Pattern: BitmapZone bitmapZone = BitmapZone.From(originalBitmap, x , y, width, height); Factory Method Pattern: BitmapZone bitmapZone = BitmapZone.FromBitmap(originalBitmap, x, y, width, height); Other? Why? Thanks

    Read the article

  • REST web service keeps first POST parametrs

    - by Diego
    I have a web service in REST, designed with Java and deployed on Tomcat. This is the web service structure: @Path("Personas") public class Personas { @Context private UriInfo context; /** * Creates a new instance of ServiceResource */ public Personas() { } @GET @Produces("text/html") public String consultarEdad (@QueryParam("nombre") String nombre) { ConectorCliente c = new ConectorCliente("root", "cafe.sql", "test"); int edad = c.consultarEdad(nombre); if (edad == Integer.MIN_VALUE) return "-1"; return String.valueOf(edad); } @POST @Produces("text/html") public String insertarPersona(@QueryParam("nombre") String msg, @QueryParam("edad") int edad) { ConectorCliente c = new ConectorCliente("usr", "passwd", "dbname"); c.agregar(msg, edad); return "listo"; } } Where ConectorCliente class is MySQL connector and querying class. So, I had tested this with the @GET actually doing POST work, any user inputed data and information from ma Java FX app and it went direct to webservice's database. However, I changed so the CREATE operation was performed through a webservice responding to an actual POST HTTP request. However, when I run the client and add some info, parameters go OK, but in next time I input different parameters it'll input the same. I run this several times and I can't get the reason of it. This is the clients code: public class WebServicePersonasConsumer { private WebTarget webTarget; private Client client; private static final String BASE_URI = "http://localhost:8080/GetSomeRest/serviciosweb/"; public WebServicePersonasConsumer() { client = javax.ws.rs.client.ClientBuilder.newClient(); webTarget = client.target(BASE_URI).path("Personas"); } public <T> T insertarPersona(Class<T> responseType, String nombre, String edad) throws ClientErrorException { String[] queryParamNames = new String[]{"nombre", "edad"}; String[] queryParamValues = new String[]{nombre, edad}; ; javax.ws.rs.core.Form form = getQueryOrFormParams(queryParamNames, queryParamValues); javax.ws.rs.core.MultivaluedMap<String, String> map = form.asMap(); for (java.util.Map.Entry<String, java.util.List<String>> entry : map.entrySet()) { java.util.List<String> list = entry.getValue(); String[] values = list.toArray(new String[list.size()]); webTarget = webTarget.queryParam(entry.getKey(), (Object[]) values); } return webTarget.request().post(null, responseType); } public <T> T consultarEdad(Class<T> responseType, String nombre) throws ClientErrorException { String[] queryParamNames = new String[]{"nombre"}; String[] queryParamValues = new String[]{nombre}; ; javax.ws.rs.core.Form form = getQueryOrFormParams(queryParamNames, queryParamValues); javax.ws.rs.core.MultivaluedMap<String, String> map = form.asMap(); for (java.util.Map.Entry<String, java.util.List<String>> entry : map.entrySet()) { java.util.List<String> list = entry.getValue(); String[] values = list.toArray(new String[list.size()]); webTarget = webTarget.queryParam(entry.getKey(), (Object[]) values); } return webTarget.request(javax.ws.rs.core.MediaType.TEXT_HTML).get(responseType); } private Form getQueryOrFormParams(String[] paramNames, String[] paramValues) { Form form = new javax.ws.rs.core.Form(); for (int i = 0; i < paramNames.length; i++) { if (paramValues[i] != null) { form = form.param(paramNames[i], paramValues[i]); } } return form; } public void close() { client.close(); } } And this this the code when I perform the operations in a Java FX app: String nombre = nombreTextField.getText(); String edad = edadTextField.getText(); String insertToDatabase = consumidor.insertarPersona(String.class, nombre, edad); So, as parameters are taken from TextFields, is quite odd why second, third, fourth and so on POSTS post the SAME.

    Read the article

  • Customer Attribute, not sorting select options

    - by Bosworth99
    Made a module that creates some customer EAV attributes. One of these attributes is a Select, and I'm dropping a bunch of options into their respective tables. Everything lines up and is accessible on both the front end and the back. Last thing before calling this part of things finished is the sort order of the options. They come out all scrambled, instead of the obvious default or alphabetical (seemingly at random... very wierd). I'm on Mage v1.11 (Pro/Enterprise). config.xml <config> <modules> <WACI_CustomerAttr> <version>0.1.0</version> </WACI_CustomerAttr> </modules> <global> <resources> <customerattr_setup> <setup> <module>WACI_CustomerAttr</module> <class>Mage_Customer_Model_Entity_Setup</class> </setup> <connection> <use>core_setup</use> </connection> </customerattr_setup> </resources> <models> <WACI_CustomerAttr> <class>WACI_CustomerAttr_Model</class> </WACI_CustomerAttr> </models> <fieldsets> <customer_account> <agency><create>1</create><update>1</update></agency> <title><create>1</create><update>1</update></title> <phone><create>1</create><update>1</update></phone> <mailing_address><create>1</create><update>1</update></mailing_address> <city><create>1</create><update>1</update></city> <state><create>1</create><update>1</update></state> <zip><create>1</create><update>1</update></zip> <fed_id><create>1</create><update>1</update></fed_id> <ubi><create>1</create><update>1</update></ubi> </customer_account> </fieldsets> </global> </config> mysql4-install-0.1.0.php <?php Mage::log('Installing WACI_CustomerAttr'); echo 'Running Upgrade: '.get_class($this)."\n <br /> \n"; //die ( 'its running' ); $installer = $this; /* @var $installer Mage_Customer_Model_Entity_Setup */ $installer->startSetup(); // bunch of attributes // State $installer->addAttribute('customer','state', array( 'type' => 'varchar', 'group' => 'Default', 'label' => 'State', 'input' => 'select', 'default' => 'Washington', 'source' => 'WACI_CustomerAttr/customer_attribute_data_select', 'global' => Mage_Catalog_Model_Resource_Eav_Attribute::SCOPE_STORE, 'required' => true, 'visible' => true, 'user_defined' => 1, 'position' => 67 ) ); $attrS = Mage::getSingleton('eav/config')->getAttribute('customer', 'state'); $attrS->addData(array('sort_order'=>67)); $attrS->setData('used_in_forms', array('adminhtml_customer','customer_account_edit','customer_account_create'))->save(); $state_list = array('Alabama','Alaska','Arizona','Arkansas','California','Colorado','Connecticut','Delaware','Florida','Georgia', 'Hawaii','Idaho','Illinois','Indiana','Iowa','Kansas','Kentucky','Louisiana','Maine','Maryland','Massachusetts','Michigan', 'Minnesota','Mississippi','Missouri','Montana','Nebraska','Nevada','New Hampshire','New Jersey','New Mexico','New York', 'North Carolina','North Dakota','Ohio','Oklahoma','Oregon','Pennsylvania','Rhode Island','South Carolina','South Dakota', 'Tennessee','Texas','Utah','Vermont','Virginia','Washington','West Virginia','Wisconsin','Wyoming'); $aOption = array(); $aOption['attribute_id'] = $installer->getAttributeId('customer', 'state'); for($iCount=0;$iCount<sizeof($state_list);$iCount++){ $aOption['value']['option'.$iCount][0] = $state_list[$iCount]; } $installer->addAttributeOption($aOption); // a few more $installer->endSetup(); app/code/local/WACI/CustomerAttr/Model/Customer/Attribute/Data/Select.php <?php class WACI_CustomerAttr_Model_Customer_Attribute_Data_Select extends Mage_Eav_Model_Entity_Attribute_Source_Abstract{ function getAllOptions(){ if (is_null($this->_options)) { $this->_options = Mage::getResourceModel('eav/entity_attribute_option_collection') ->setAttributeFilter($this->getAttribute()->getId()) ->setStoreFilter($this->getAttribute()->getStoreId()) ->setPositionOrder('asc') ->load() ->toOptionArray(); } $options = $this->_options; return $options; } } theme/variation/template/persistent/customer/form/register.phtml <li> <?php $attribute = Mage::getModel('eav/config')->getAttribute('customer','state'); ?> <label for="state" class="<?php if($attribute->getIsRequired() == true){?>required<?php } ?>"><?php if($attribute->getIsRequired() == true){?><em>*</em><?php } ?><?php echo $this->__('State') ?></label> <div class="input-box"> <select name="state" id="state" class="<?php if($attribute->getIsRequired() == true){?>required-entry<?php } ?>"> <?php $options = $attribute->getSource()->getAllOptions(); foreach($options as $option){ ?> <option value='<?php echo $option['value']?>' <?php if($this->getFormData()->getState() == $option['value']){ echo 'selected="selected"';}?>><?php echo $this->__($option['label'])?></option> <?php } ?> </select> </div> </li> All options are getting loaded into table eav_attribute_option just fine (albeit without a sort_order defined), as well as table eav_attribute_option_value. In the adminhtml / customer-manage customers-account information this select is showing up fine (but its delivered automatically by the system). Seems I should be able to set the sort-order on creation of the attributeOptions, or, certainly, define the sort order in the data/select class. But nothing I've tried works. I'd rather not do a front-end hack either... Oh, and how do I set the default value of this select? (Different question, I know, but related). Setting the attributes 'default' = 'washington' seems to do nothing. There seem to be a lot of ways to set up attribute select options like this. Is there a better way that the one I've outlined here? Perhaps I'm messing something up. Cheers

    Read the article

  • Serializing QGraphicsScene contents

    - by Rob
    I am using the Qt QGraphicsScene class, adding pre-defined items such as QGraphicsRectItem, QGraphicsLineItem, etc. and I want to serialize the scene contents to disk. However, the base QGraphicsItem class (that the other items I use derive from) doesn't support serialization so I need to roll my own code. The problem is that all access to these objects is via a base QGraphicsItem pointer, so the serialization code I have is horrible: QGraphicsScene* scene = new QGraphicsScene; scene->addRect(QRectF(0, 0, 100, 100)); scene->addLine(QLineF(0, 0, 100, 100)); ... QList<QGraphicsItem*> list = scene->items(); foreach (QGraphicsItem* item, items) { if (item->type() == QGraphicsRectItem::Type) { QGraphicsRectItem* rect = qgraphicsitem_cast<QGraphicsRectItem*>(item); // Access QGraphicsRectItem members here } else if (item->type() == QGraphicsLineItem::Type) { QGraphicsLineItem* line = qgraphicsitem_cast<QGraphicsLineItem*>(item); // Access QGraphicsLineItem members here } ... } This is not good code IMHO. So, instead I could create an ABC class like this: class Item { public: virtual void serialize(QDataStream& strm, int version) = 0; }; class Rect : public QGraphicsRectItem, public Item { public: void serialize(QDataStream& strm, int version) { // Serialize this object } ... }; I can then add Rect objects using QGraphicsScene::addItem(new Rect(,,,)); But this doesn't really help me as the following will crash: QList<QGraphicsItem*> list = scene->items(); foreach (QGraphicsItem* item, items) { Item* myitem = reinterpret_class<Item*>(item); myitem->serialize(...) // FAIL } Any way I can make this work?

    Read the article

  • What makes this "declarator invalid"? C++

    - by nieldw
    I have Vertex template in vertex.h. From my graph.h: 20 template<class edgeDecor, class vertexDecor, bool dir> 21 class Vertex; which I use in my Graph template. I've used the Vertex template successfully throughout my Graph, return pointers to Vertices, etc. Now for the first time I am trying to declare and instantiate a Vertex object, and gcc is telling me that my 'declarator' is 'invalid'. How can this be? 81 template<class edgeDecor, class vertexDecor, bool dir> 82 Graph<edgeDecor,int,dir> Graph<edgeDecor,vertexDecor,dir>::Dijkstra(vertex s, bool print = false) const 83 { 84 /* Construct new Graph with apropriate decorators */ 85 Graph<edgeDecor,int,dir> span = new Graph<edgeDecor,int,dir>(); 86 span.E.reserve(this->E.size()); 87 88 typename Vertex<edgeDecor,int,dir> v = new Vertex(INT_MAX); 89 span.V = new vector<Vertex<edgeDecor,int,dir> >(this->V.size,v); 90 }; And gcc is saying: graph.h: In member function ‘Graph<edgeDecor, int, dir> Graph<edgeDecor, vertexDecor, dir>::Dijkstra(Vertex<edgeDecor, vertexDecor, dir>, bool) const’: graph.h:88: error: invalid declarator before ‘v’ graph.h:89: error: ‘v’ was not declared in this scope I know this is probably another noob question, but I'll appreciate any help.

    Read the article

  • c++ - strange problem with polymorphism - cellular automaton

    - by Green
    Hello, I am making "game of life" implementation that, when cell has: two live neighbours I make object of class CCellB two live neighbours I make object of class CCellA when has 3 or <2 I make object of class CCellX (dead) Class CCell is base of CCellA, CCellB, CCellX My problem is: That works fine, until I change new CCell(); to new CCellB();: CCell ***temp = allocateArray(); for(int i = 0; i < n; i++) { for(int j = 0; j < m; j++) { c = arr[i][j]->countAliveNeighbor(); if(c == 3) { temp[i][j] = new CCellA(); temp[i][j]->alive = 1; }else if(c == 2) { temp[i][j] = new CCell(); // HERE, WHEN I CHANGE IT TO CCELLB IT DON'T WORKS temp[i][j]->alive = tab[i][j]->alive; }else if((c >= 4)||(c < 2)) { temp[i][j] = new CCellX(); } } } Then it seems don't work properly... Seems like neighbours are not count properly, Cell with 4,5 neighbours still alive alive var is member of base class - CCell, all is public, please help!

    Read the article

  • HTML: How to get a child element to show behidn (lower z-index) than its parent

    - by dclowd9901
    I need for a certain dynamic element to always appear on top of another element, no matter what order in the DOM tree they are. Is this possible? I've tried z-index (with position: relative), and it doesn't seem to work. I hate to be vague, but this is the simplest way I can think of asking this question without explaining its purpose ad nauseum. So, to recap, I need <div class="a"> <div class="b"></div> </div> <div class="b"> <div class="a"></div> </div> To display exactly the same when rendered. And for flexibility purposes (I'm planning on distributing a plugin that needs this functionality), I'd really like to not have to resort to absolute or fixed positioning.

    Read the article

  • Python C API from C++ app - know when to lock

    - by Alex
    Hi Everyone, I am trying to write a C++ class that calls Python methods of a class that does some I/O operations (file, stdout) at once. The problem I have ran into is that my class is called from different threads: sometimes main thread, sometimes different others. Obviously I tried to apply the approach for Python calls in multi-threaded native applications. Basically everything starts from PyEval_AcquireLock and PyEval_ReleaseLock or just global locks. According to the documentation here when a thread is already locked a deadlock ensues. When my class is called from the main thread or other one that blocks Python execution I have a deadlock. Python Cfunc1() - C++ func that creates threads internally which lead to calls in "my class", It stuck on PyEval_AcquireLock, obviously the Python is already locked, i.e. waiting for C++ Cfunc1 call to complete... It completes fine if I omit those locks. Also it completes fine when Python interpreter is ready for the next user command, i.e. when thread is calling funcs in the background - not inside of a native call I am looking for a workaround. I need to distinguish whether or not the global lock is allowed, i.e. Python is not locked and ready to receive the next command... I tried PyGIL_Ensure, unfortunately I see hang. Any known API or solution for this ? (Python 2.4)

    Read the article

  • Adding DataAnnontations to Generated Partial Classes

    - by Naz
    Hi I have a Subsonic3 Active Record generated partial User class which I've extended on with some methods in a separate partial class. I would like to know if it is possible to add Data Annotations to the member properties on one partial class where it's declared on the other Subsonic Generated one I tried this. public partial class User { [DataType(DataType.EmailAddress, ErrorMessage = "Please enter an email address")] public string Email { get; set; } ... } That examples gives the "Member is already defined" error. I think I might have seen an example a while ago of what I'm trying to do with Dynamic Data and Linq2Sql.

    Read the article

  • Multiple Submit Buttons problem in Struts2

    - by umesh awasthi
    Hi All, Trying to work with multiple submit buttons within a single form in struts2 application but not able to work. here is the jsp code i am using <tr> <td class="button"><input type="submit" value="Import" name="destinationImport" class="button"></td> <td class="button"><input type="submit" value="Export" name="destinationExport" class="button"></td> </tr> here is the java part private boolean destinationImport; private boolean destinationExport; and there respective setter and getter but i am sure is that Struts2 type convertor is having problem converting the String value to boolean do any one have idea how to achieve this Thanks in advance

    Read the article

  • Using Spring as a JPA Container

    - by sdoca
    Hi, I found this article which talks about using Spring as a JPA container: http://java.sys-con.com/node/366275 I have never used Spring before this and am trying to make this work and hope someone can help me. In the article it states that you need to annotate a Spring bean with @Transactional and methods/fields with @PersistenceContext in order to provide transaction support and to inject an entity manager. Is there something the defines a bean as a "Spring Bean"? I have a bean class which implements CRUD operations on entities using generics: @Transactional public class GenericCrudServiceBean implements GenericCrudService { @PersistenceContext(unitName="MyData") private EntityManager em; @Override @PersistenceContext public <T> T create(T t) { em.persist(t); return t; } @Override @PersistenceContext public <T> void delete(T t) { t = em.merge(t); em.remove(t); } ... ... ... @Override @PersistenceContext public List<?> findWithNamedQuery(String queryName) { return em.createNamedQuery(queryName).getResultList(); } } Originally I only had this peristence context annotation: @PersistenceContext(unitName="MyData") private EntityManager em; but had a null em when findWithNamedQuery was invoked. Then I annotated the methods as well, but em is still null (no injection?). I was wondering if this had something to do with my bean not being recognized as "Spring". I have done configuration as best I could following the directions in the article including setting the following in my context.xml file: <?xml version="1.0" encoding="UTF-8"?> <beans xmlns:tx="http://www.springframework.org/schema/tx" tx:schemaLocation="http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd"> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="persistenceUnitName" value="MyData" /> <property name="dataSource" ref="dataSource" /> <property name="loadTimeWeaver" class="org.springframework.classloading.ReflectiveLoadTimeWeaver" /> <property name="jpaVendorAdapter" ref="jpaAdapter" /> </bean> <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close"> <property name="driverClassName" value="oracle.jdbc.driver.OracleDriver" /> <property name="url" value="jdbc:oracle:thin:@localhost:1521:MySID" /> <property name="username" value="user" /> <property name="password" value="password" /> <property name="initialSize" value="3" /> <property name="maxActive" value="10" /> </bean> <bean id="jpaAdapter" class="org.springframework.orm.jpa.vendor.EclipseLinkJpaVendorAdapter"> <property name="databasePlatform" value="org.eclipse.persistence.platform.database.OraclePlatform" /> <property name="showSql" value="true" /> </bean> <bean class="org.springframework.ormmjpa.support.PersistenceAnnotationBeanPostProcessor" /> <tx:annotation-driven /> </beans> I guessed that these belonged in the context.xml file because the article never specifically said which file is the "application context" file. If this is wrong, please let me know.

    Read the article

< Previous Page | 395 396 397 398 399 400 401 402 403 404 405 406  | Next Page >