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[Struts2+tiles] How can I make title dynamically?

- by Lee Domin

I'm developing BBS in struts2 and tiles(2) framework. I want to push a value in ActionSupport class and pop the value in layout.jsp of tiles. but i just keep failing to access to the value. I will explain my works step by step. 1) Users click a link to view an article at list page. And BoardView class will be called as defined in struts.xml --list.jsp-- <a href="view_board?num=${num}"> ${ subject } </a> --struts.xml-- <action name="View_board" class="board.BoardView"> <result type="tiles">board.view</result> </action> 2)Action class will put title into the value stack... right? --BoardView class-- public class BoardView extends ActionSupport private String title; public void Execute() throws Exception { ... setTitle(board.getSubject()); return SUCCESS; } ... (setter and getter of title) 3) As ActionClass returns SUCCESS, it will go to tiles definition named board.view --struts.xml-- <action name="View_board" class="board.BoardView"> <result type="tiles">board.view</result> </action> 4)Here's the tiles-def.xml and the problem. I think the value of 'title' can't be popped from value stack. ==tiles-def.xml== <definition name="board.view" extends="layout"> <put-attribute name="title" value="%title" /> <put-attribute name="body" value="/board/view.jsp" /> </definition> (I can't indent with tags... sorry) Here's the layout.jsp ==layout.jsp== ... <title><tiles:getAsString name="title" /></title> ... I tried to replace the value attribute to %{title}, $title and ${title}. But nothings worked out. Web Browser just shows the string itself($title). I don't know what to do... please help me. I hope you all understand my works despite of my bad explanation.

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VS 2008 irritating copy constructor link dependency

- by Paul Hollingsworth

Hi guys, I've run into the following annoying and seemingly incorrect behaviour in the Visual Studio 2008 C++ compiler: Suppose I have a class library - Car.lib - that uses a "Car" class, with a header called "Car.h": class Car { public: void Drive() { Accelerate(); } void Accelerate(); }; What I'm actually trying to do is use the Car headers (for some other functions), but without having to link with Car.lib itself (the actual class is not called "Car" but I am sanitising this example). If I #include "Car.h" in the .cpp file used to build a managed C++ .dll, but never refer to Car, everything compiles and links fine. This is because I never instantiate a Car object. However, the following: namespace { class Car { public: Car(const Car& rhs) { Accelerate(); } void Accelerate(); }; } leaves me with the link error: Error 2 error LNK2001: unresolved external symbol "public: void __thiscall `anonymous namespace'::Car::Accelerate(void)" (?Accelerate@Car@?A0xce3bb5ed@@$$FQAEXXZ) CREObjectWrapper.obj CREObjectBuilderWrapper Note I've declared the whole thing inside an anonymous namespace so there's no way that the Car functions could be exported from the .DLL in any case. Declaring the copy constructor out-of-line makes no difference. i.e. the following also fails to link: class Car { public: Car(const Car& rhs); void Accelerate(); }; Car::Car(const Car& rhs) { Accelerate(); } It's something specifically to do with the copy constructor note, because the following, for example, does link: class Car { public: Car() { Accelerate(); } void Accelerate(); }; I am not a C++ standards guru but this doesn't seem correct to me. Surely the compiler still should not have had to even generate any code that calls the Car copy constructor. Can anyone confirm if this behaviour is correct? It's been a while since I used C++ - but I don't think this used to be an issue with Visual Studio 6.0 for example. Can anyone suggest a workaround that allows one to "re-use" the Accelerate method from within the copy constructor and still have the copy constructor declared inline?

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Enable PostBack for a ASP.NET User Control

- by Steven

When I click my "Query" the values for my user controls are reset. How do I enable PostBack for my user control? myDatePicker.ascx <%@ Control Language="vb" CodeBehind="myDatePicker.ascx.vb" Inherits="Website.myDate" AutoEventWireup="false" %> <%@ Register assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" tagprefix="asp" %> <asp:TextBox ID="DateTxt" runat="server" ReadOnly="True" /> <asp:Image ID="DateImg" runat="server" ImageUrl="~/Calendar_scheduleHS.png" EnableViewState="True" EnableTheming="True" /> <asp:CalendarExtender ID="DateTxt_CalendarExtender" runat="server" Enabled="True" TargetControlID="DateTxt" PopupButtonID="DateImg" DefaultView="Days" Format="ddd MMM dd, yyyy" EnableViewState="True"/> myDatePicker.ascx Partial Public Class myDate Inherits System.Web.UI.UserControl Public Property SelectedDate() As Date? Get Dim o As Object = ViewState("SelectedDate") If o = Nothing Then Return Nothing End If Return Date.Parse(o) End Get Set(ByVal value As Date?) ViewState("SelectedDate") = value End Set End Property End Class Default.aspx <%@ Page Language="vb" AutoEventWireup="false" CodeBehind="Default.aspx.vb" Inherits="Website._Default" EnableEventValidation="false" EnableViewState="true" %> <%@ Register TagPrefix="my" TagName="DatePicker" Src="~/myDatePicker.ascx" %> <%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="ajax" %> <%@ Register Assembly="..." Namespace="System.Web.UI.WebControls" TagPrefix="asp" %> <!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"> ... <body> <form id="form1" runat="server"> <div class="mainbox"> <div class="query"> Start Date<br /> <my:DatePicker ID="StartDate" runat="server" EnableViewState="True" /> End Date <br /> <my:DatePicker ID="EndDate" runat="server" EnableViewState="True" /> ... <div class="query_buttons"> <asp:Button ID="Button1" runat="server" Text="Query" /> </div> </div> <asp:GridView ID="GridView1" ... > </form> </body> </html> Default.aspx.vb Imports System.Web.Services Imports System.Web.Script.Services Imports AjaxControlToolkit Protected Sub Page_Load(ByVal sender As Object, _ ByVal e As EventArgs) Handles Me.Load End Sub Partial Public Class _Default Inherits System.Web.UI.Page Protected Sub Button1_Click(ByVal sender As Object, _ ByVal e As EventArgs) Handles Button1.Click GridView1.DataBind() End Sub End Class

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when to use the abstract factory pattern?

- by hguser

Hi: I want to know when we need to use the abstract factory pattern. Here is an example,I want to know if it is necessary. The UML THe above is the abstract factory pattern, it is recommended by my classmate. THe following is myown implemention. I do not think it is necessary to use the pattern. And the following is some core codes: package net; import java.io.IOException; import java.util.HashMap; import java.util.Map; import java.util.Properties; public class Test { public static void main(String[] args) throws IOException, InstantiationException, IllegalAccessException, ClassNotFoundException { DaoRepository dr=new DaoRepository(); AbstractDao dao=dr.findDao("sql"); dao.insert(); } } class DaoRepository { Map<String, AbstractDao> daoMap=new HashMap<String, AbstractDao>(); public DaoRepository () throws IOException, InstantiationException, IllegalAccessException, ClassNotFoundException { Properties p=new Properties(); p.load(DaoRepository.class.getResourceAsStream("Test.properties")); initDaos(p); } public void initDaos(Properties p) throws InstantiationException, IllegalAccessException, ClassNotFoundException { String[] daoarray=p.getProperty("dao").split(","); for(String dao:daoarray) { AbstractDao ad=(AbstractDao)Class.forName(dao).newInstance(); daoMap.put(ad.getID(),ad); } } public AbstractDao findDao(String id) {return daoMap.get(id);} } abstract class AbstractDao { public abstract String getID(); public abstract void insert(); public abstract void update(); } class SqlDao extends AbstractDao { public SqlDao() {} public String getID() {return "sql";} public void insert() {System.out.println("sql insert");} public void update() {System.out.println("sql update");} } class AccessDao extends AbstractDao { public AccessDao() {} public String getID() {return "access";} public void insert() {System.out.println("access insert");} public void update() {System.out.println("access update");} } And the content of the Test.properties is just one line: dao=net.SqlDao,net.SqlDao So any ont can tell me if this suitation is necessary?

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Hibernate + Spring : cascade deletion ignoring non-nullable constraints

- by E.Benoît

Hello, I seem to be having one weird problem with some Hibernate data classes. In a very specific case, deleting an object should fail due to existing, non-nullable relations - however it does not. The strangest part is that a few other classes related to the same definition behave appropriately. I'm using HSQLDB 1.8.0.10, Hibernate 3.5.0 (final) and Spring 3.0.2. The Hibernate properties are set so that batch updates are disabled. The class whose instances are being deleted is: @Entity( name = "users.Credentials" ) @Table( name = "credentials" , schema = "users" ) public class Credentials extends ModelBase { private static final long serialVersionUID = 1L; /* Some basic fields here */ /** Administrator credentials, if any */ @OneToOne( mappedBy = "credentials" , fetch = FetchType.LAZY ) public AdminCredentials adminCredentials; /** Active account data */ @OneToOne( mappedBy = "credentials" , fetch = FetchType.LAZY ) public Account activeAccount; /* Some more reverse relations here */ } (ModelBase is a class that simply declares a Long field named "id" as being automatically generated) The Account class, which is one for which constraints work, looks like this: @Entity( name = "users.Account" ) @Table( name = "accounts" , schema = "users" ) public class Account extends ModelBase { private static final long serialVersionUID = 1L; /** Credentials the account is linked to */ @OneToOne( optional = false ) @JoinColumn( name = "credentials_id" , referencedColumnName = "id" , nullable = false , updatable = false ) public Credentials credentials; /* Some more fields here */ } And here is the AdminCredentials class, for which the constraints are ignored. @Entity( name = "admin.Credentials" ) @Table( name = "admin_credentials" , schema = "admin" ) public class AdminCredentials extends ModelBase { private static final long serialVersionUID = 1L; /** Credentials linked with an administrative account */ @OneToOne( optional = false ) @JoinColumn( name = "credentials_id" , referencedColumnName = "id" , nullable = false , updatable = false ) public Credentials credentials; /* Some more fields here */ } The code that attempts to delete the Credentials instances is: try { if ( account.validationKey != null ) { this.hTemplate.delete( account.validationKey ); } this.hTemplate.delete( account.languageSetting ); this.hTemplate.delete( account ); } catch ( DataIntegrityViolationException e ) { return false; } Where hTemplate is a HibernateTemplate instance provided by Spring, its flush mode having been set to EAGER. In the conditions shown above, the deletion will fail if there is an Account instance that refers to the Credentials instance being deleted, which is the expected behaviour. However, an AdminCredentials instance will be ignored, the deletion will succeed, leaving an invalid AdminCredentials instance behind (trying to refresh that instance causes an error because the Credentials instance no longer exists). I have tried moving the AdminCredentials table from the admin DB schema to the users DB schema. Strangely enough, a deletion-related error is then triggered, but not in the deletion code - it is triggered at the next query involving the table, seemingly ignoring the flush mode setting. I've been trying to understand this for hours and I must admit I'm just as clueless now as I was then.

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Where to put default-servlet-handler in Spring MVC configuration

- by gigadot

In my web.xml, the default servlet mapping, i.e. /, is mapped to Spring dispatcher. In my Spring dispatcher configuration, I have DefaultAnnotationHandlerMapping, ControllerClassNameHandlerMapping and AnnotationMethodHandlerAdapter which allows me to map url to controllers either by its class name or its @Requestmapping annotation. However, there are some static resources under the web root which I also want spring dispatcher to serve using default servlet. According to Spring documentation, this can be done using <mvc:default-servlet-handler/> tag. In the configuration below, there are 4 candidate locations that I marked which are possible to insert this tag. Inserting the tag in different location causes the dispatcher to behave differently as following : Case 1 : If I insert it at location 1, the dispatcher will no longer be able to handle mapping by the @RequestMapping and controller class name but it will be serving the static content normally. Cas 2, 3 : It will be able to handle mapping by the @RequestMapping and controller class name as well as serving the static content if other mapping cannot be done successfully. Case 4 : It will not be able to serve the static contents. Therefore, Case 2 and 3 are desirable .According to Spring documentation, this tag configures a handler which precedence order is given to lowest so why the position matters? and Which is the best position to put this tag? <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"> <context:annotation-config/> <context:component-scan base-package="webapp.controller"/>   <bean id="annotationUrlMapping" class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping"/>  <bean id="controllerClassNameHandlerMapping" class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping"/>  <bean id="annotationMethodHandlerAdapter" class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"/>  <mvc:default-servlet-handler/>  <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> <property name="prefix" value="/WEB-INF/jsp/"/> <property name="suffix" value=".jsp"/> </bean> </beans>

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Partial overriding in Java (or dynamic overriding while overloading)

- by Lie Ryan

If I have a parent-child that defines some method .foo() like this: class Parent { public void foo(Parent arg) { System.out.println("foo in Function"); } } class Child extends Parent { public void foo(Child arg) { System.out.println("foo in ChildFunction"); } } When I called them like this: Child f = new Child(); Parent g = f; f.foo(new Parent()); f.foo(new Child()); g.foo(new Parent()); g.foo(new Child()); the output is: foo in Parent foo in Child foo in Parent foo in Parent But, I want this output: foo in Parent foo in Child foo in Parent foo in Child I have a Child class that extends Parent class. In the Child class, I want to "partially override" the Parent's foo(), that is, if the argument arg's type is Child then Child's foo() is called instead of Parent's foo(). That works Ok when I called f.foo(...) as a Child; but if I refer to it from its Parent alias like in g.foo(...) then the Parent's foo(..) get called irrespective of the type of arg. As I understand it, what I'm expecting doesn't happen because method overloading in Java is early binding (i.e. resolved statically at compile time) while method overriding is late binding (i.e. resolved dynamically at compile time) and since I defined a function with a technically different argument type, I'm technically overloading the Parent's class definition with a distinct definition, not overriding it. But what I want to do is conceptually "partially overriding" when .foo()'s argument is a subclass of the parent's foo()'s argument. I know I can define a bucket override foo(Parent arg) in Child that checks whether arg's actual type is Parent or Child and pass it properly, but if I have twenty Child, that would be lots of duplication of type-unsafe code. In my actual code, Parent is an abstract class named "Function" that simply throws NotImplementedException(). The children includes "Polynomial", "Logarithmic", etc and .foo() includes things like Child.add(Child), Child.intersectionsWith(Child), etc. Not all combination of Child.foo(OtherChild) are solvable and in fact not even all Child.foo(Child) is solvable. So I'm best left with defining everything undefined (i.e. throwing NotImplementedException) then defines only those that can be defined. So the question is: Is there any way to override only part the parent's foo()? Or is there a better way to do what I want to do?

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jQuery dialog width resizing problem

- by ktMen

I try to load some HTML code into a jQueryUI dialog by AJAX. The code itself is a list, where rightmost elements should be absolutely positioned so that the list looks like a table with two columns, but only in some rows. The problem is that jQueryUI plugin does not seem to be correctly resizing the dialog's width, which I think is due to the absolute positioning of some li's. I have read some answers to other similar questions, but none helped me out with this. This is the code I load: <style type="text/css"> ul {list-style-type:none;margin:0px;padding:0px;} ul ul {margin:0px;padding:0px;} ul>li.fila {margin-bottom:5px;padding-bottom:5px;} ul li.fila ul li { display:inline; padding-left:20px; position:relative; margin-bottom:10px; } ul li.fila ul li.O { background:url(bullet.gif) 5px 8px no-repeat; list-style-position:inside; } </style> <ul id="raiz" > <li class="fila"> <ul > <li style="position:absolute;left:0px;" class="O"> <label for="col1">Col1:</label> <input type="text" name="col1" id="col1" value="vCol1" class="text ui-widget-content ui-corner-all" /> </li> <li style="left:250px;" class="O" > <label for="col2">Col2:</label> <input type="text" name="col2" id="col2" value="vCol2" class="text ui-widget-content ui-corner-all" /> </li> </ul> </li> <li class="fila"> <ul > <li> <label for="col3">Col3:</label> <input type="text" name="col3" id="col3" value="vCol3" class="text ui-widget-content ui-corner-all" /> </li> </ul> </li> </ul> And the Dialog constructor: $("#dialog").dialog({ bgiframe: true, autoOpen: false, height: 'auto', width: 'auto', modal: true, buttons:{ 'Cancel': function() { $(this).dialog('close'); } }, open: function(event,ui){ $("#dialog").load("dialogCode.html"); } }); Thanks in advance for any suggestions.

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What are the benefits of using ORM over XML Serialization/Deserialization?

- by Tequila Jinx

I've been reading about NHibernate and Microsoft's Entity Framework to perform Object Relational Mapping against my data access layer. I'm interested in the benefits of having an established framework to perform ORM, but I'm curious as to the performance costs of using it against standard XML Serialization and Deserialization. Right now, I develop stored procedures in Oracle and SQL Server that use XML Types for either input or output parameters and return or shred XML depending on need. I use a custom database command object that uses generics to deserialize the XML results into a specified serializable class. By using a combination of generics, xml (de)serialization and Microsoft's DAAB, I've got a process that's fairly simple to develop against regardless of the data source. Moreover, since I exclusively use Stored Procedures to perform database operations, I'm mostly protected from changes in the data structure. Here's an over-simplified example of what I've been doing. static void main() { testXmlClass test = new test(1); test.Name = "Foo"; test.Save(); } // Example Serializable Class ------------------------------------------------ [XmlRootAttribute("test")] class testXmlClass() { [XmlElement(Name="id")] public int ID {set; get;} [XmlElement(Name="name")] public string Name {set; get;} //create an instance of the class loaded with data. public testXmlClass(int id) { GenericDBProvider db = new GenericDBProvider(); this = db.ExecuteSerializable("myGetByIDProcedure"); } //save the class to the database... public Save() { GenericDBProvider db = new GenericDBProvider(); db.AddInParameter("myInputParameter", DbType.XML, this); db.ExecuteSerializableNonQuery("mySaveProcedure"); } } // Database Handler ---------------------------------------------------------- class GenericDBProvider { public T ExecuteSerializable<T>(string commandText) where T : class { XmlSerializer xml = new XmlSerializer(typeof(T)); // connection and command code is assumed for the purposes of this example. // the final results basically just come down to... return xml.Deserialize(commandResults) as T; } public void ExecuteSerializableNonQuery(string commandText) { // once again, connection and command code is assumed... // basically, just execute the command along with the specified // parameters which have been serialized. } public void AddInParameter(string name, DbType type, object value) { StringWriter w = new StringWriter(); XmlSerializer x = new XmlSerializer(value.GetType()); //handle serialization for serializable classes. if (type == DbType.Xml && (value.GetType() != typeof(System.String))) { x.Serialize(w, value); w.Close(); // store serialized object in a DbParameterCollection accessible // to my other methods. } else { //handle all other parameter types } } } I'm starting a new project which will rely heavily on database operations. I'm very curious to know whether my current practices will be sustainable in a high-traffic situation and whether or not I should consider switching to NHibernate or Microsoft's Entity Framework to perform what essentially seems to boil down to the same thing I'm currently doing. I appreciate any advice you may have.

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Decode the string encoded through php in javascript

- by Pankaj Khurana

Hi, I am working on a facebook page in which i have used ajax & response is returned in json format. I have encoded the string in php. Now i want to decode that string in javascript. foreach($feedbackdetails as $feedbackdetail) { $str.= '<div class="tweet"> <img style="cursor:pointer;" id="imgVoteUp" src="http://myserver/facebook/vote_up.gif" alt="Vote Up" title="Vote Up" onclick="saveVote('.$feedbackdetail[pk_feedbackid].',1)" /> : '.$feedbackdetail[upvotecount].' <img style="cursor:pointer;" id="imgVoteDown" src="http://myserver/facebook/vote_down.gif" alt="Vote Down" title="Vote Down" onclick="saveVote('.$feedbackdetail[pk_feedbackid].',0)" /> : '.$feedbackdetail[downvotecount].' <p class="'.$pclass.'">'.$feedbackdetail[title].' by '.$feedbackdetail[name].'<br>'.$feedbackdetail[description].'</p></div>'; } $str=urlencode($str); echo '{"fbml_test":"'.$str.'"}'; Javascript Function: function saveVote(id,type,class) { contentdiv='div_'+id; processdiv='processdiv_'+id; document.getElementById(processdiv).setInnerXHTML('<span id="caric"><center><img src="http://static.ak.fbcdn.net/rsrc.php/z5R48/hash/ejut8v2y.gif" /></center></span>'); posturl='http://myserver/facebook/vote.php'; if(class==0) { class='firstmessage'; } else { class='message'; } var queryString = "?id="+id+"&type="+type+"&pclass="+class; posturl = posturl +queryString; ajax = new Ajax(); ajax.responseType = Ajax.JSON; ajax.requireLogin = true; ajax.ondone = function(data) { document.getElementById('caric').setStyle('display','none'); //new Dialog().showMessage('Dialog',data); if(data.error) { new Dialog().showMessage('Dialog',data.error); } if(data.fbml_test) { document.getElementById(contentdiv).setInnerFBML(data)); } //div_id.setInnerFBML(data); } ajax.post(posturl); } Right now i am getting encoded string how can i change it? Please help me on this Thanks Pankaj

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jQuery: Sort div's according to content of different sub divs

- by rayne

I'm trying to create a somewhat complex sorting feature which neither uses divs nor lists. Unfortunately two hours of googling didn't help me. Here is the basic setup of my HTML: <div id="all_elements">  <div class="element"> <div class="wrapper"> <a href="/" title="links"> <img src="/img/image.jpg" border="0" alt="image" class="image" /></a> <div class="details"> <h3><a href="/" title="title">Name (Sort Argument 1)</a></h3> <div class="title"><a href="/" title="title">Title (Sort Argument 2)</a></div> <div class="year">2010 (Sort Argumentt 3)</div> <div class="country">Great Britain (Sort Argument 4)</div> </div> </div> </div> </div>  The setup is a bit complex, but basically .element is the element that needs to be sorted alphabetically according to either the contents of h3, div.title, div.year or div.country. So the user will be able to view the contents of the site either sorted by name, by year, by country or by title. I have this jQuery snippet from a website, but all my attempts on trying to tell it to use the contents of e.g. h3 to sort have failed. Right now it sorts pretty much randomly. jQuery.fn.sort = function() { return this.pushStack([].sort.apply(this, arguments), []); }; function sortAscending(a, b) { return a.innerHTML > b.innerHTML ? 1 : -1; }; function sortDescending(a, b) { return a.innerHTML < b.innerHTML ? 1 : -1; }; $(document).ready(function() { $("#sort").toggle( function() { $('#all_elements .element').sort(sortDescending).appendTo('#all_elements'); $(this).text("Sort Asc"); }, function() { $('#all_elements .element').sort(sortAscending).appendTo('#all_elements'); $(this).text("Sort Desc"); }); }); How can I customize the function to sort the contents of my h3 or divs?

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Method interception in PHP 5.*

- by Rolf

Hi everybody, I'm implementing a Log system for PHP, and I'm a bit stuck. All the configuration is defined in an XML file, that declares every method to be logged. XML is well parsed and converted into a multidimensionnal array (classname = array of methods). So far, so good. Let's take a simple example: #A.php class A { public function foo($bar) { echo ' // Hello there !'; } public function bar($foo) { echo " $ù$ùmezf$z !"; } } #B.php class B { public function far($boo) { echo $boo; } } Now, let's say I've this configuration file: <interceptor> <methods class="__CLASS_DIR__A.php"> <method name="foo"> <log-level>INFO</log-level> <log-message>Transaction init</log-message> </method> </methods> <methods class="__CLASS_DIR__B.php"> <method name="far"> <log-level>DEBUG</log-level> <log-message>Useless</log-message> </method> </methods> </interceptor> The thing I'd like AT RUNTIME ONLY (once the XML parser has done his job) is: #Logger.php (its definitely NOT a final version) -- generated by the XML parser class Logger { public function __call($name,$args) { $log_level = args[0]; $args = array_slice($args,1); switch($method_name) { case 'foo': case 'far': //case ..... //write in log files break; } //THEN, RELAY THE CALL TO THE INITIAL METHOD } } #"dynamic" A.php class A extends Logger { public function foo($log_level, $bar) { echo ' // Hello there !'; } public function bar($foo) { echo " $ù$ùmezf$z !"; } } #"dynamic" B.php class B extends Logger { public function far($log_level, $boo) { echo $boo; } } The big challenge here is to transform A and B into their "dynamic" versions, once the XML parser has completed its job. The ideal would be to achieve that without modifying the code of A and B at all (I mean, in the files) - or at least find a way to come back to their original versions once the program is finished. To be clear, I wanna find the most proper way to intercept method calls in PHP. What are your ideas about it ??? Thanks in advance, Rolf

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Cutom event dispatchment location

- by Martino Wullems

Hello, I've been looking into custom event (listeners) for quite some time, but never succeeded in making one. There are so many different mehods, extending the Event class, but also Extending the EventDispatcher class, very confusing! I want to settle with this once and for all and learn the appriopate technique. package{ import flash.events.Event; public class CustomEvent extends Event{ public static const TEST:String = 'test'; //what exac is the purpose of the value in the string? public var data:Object; public function CustomEvent(type:String, bubbles:Boolean = false, cancelable:Boolean = false, data:Object = null):void { this.data = data; super(); } } } As far as I know a custom class where you set the requirements for the event to be dispatched has to be made: package { import flash.display.MovieClip; public class TestClass extends MovieClip { public function TestClass():void { if (ConditionForHoldToComplete == true) { dispatchEvent(new Event(CustomEvent.TEST)); } } } } I'm not sure if this is correct, but it should be something along the lines of this. Now What I want is something like a mouseevent, which can be applied to a target and does not require a specific class. It would have to work something like this: package com.op_pad._events{ import flash.events.MouseEvent; import flash.utils.Timer; import flash.events.TimerEvent; import flash.events.EventDispatcher; import flash.events.Event; public class HoldEvent extends Event { public static const HOLD_COMPLETE:String = "hold completed"; var timer:Timer; public function SpriteEvent(type:String, bubbles:Boolean=true, cancelable:Boolean=false) { super( type, bubbles, cancelable ); timer = new Timer(1000, 1); //somehow find the target where is event is placed upon -> target.addEventlistener target.addEventListener(MouseEvent.MOUSE_DOWN, startTimer); target.addEventListener(MouseEvent.MOUSE_UP, stopTimer); } public override function clone():Event { return new SpriteEvent(type, bubbles, cancelable); } public override function toString():String { return formatToString("MovieEvent", "type", "bubbles", "cancelable", "eventPhase"); } ////////////////////////////////// ///// c o n d i t i o n s ///// ////////////////////////////////// private function startTimer(e:MouseEvent):void { timer.start(); timer.addEventListener(TimerEvent.TIMER_COMPLETE, complete); } private function stopTimer(e:MouseEvent):void { timer.stop() } public function complete(e:TimerEvent):void { dispatchEvent(new HoldEvent(HoldEvent.HOLD_COMPLETE)); } } } This obviously won't work, but should give you an idea of what I want to achieve. This should be possible because mouseevent can be applied to about everything.The main problem is that I don't know where I should set the requirements for the event to be executed to be able to apply it to movieclips and sprites. Thanks in advance

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How do I apply a servlet filter when serving an HTML page directly?

- by Philippe Beaudoin

First off, I'm using Google AppEngine and Guice, but I suspect my problem is not related to these. When the user connect to my (GWT) webapp, the URL is a direct html page. For example, in development mode, it is: http://127.0.0.1:8888/Puzzlebazar.html?gwt.codesvr=127.0.0.1:9997. Now, I setup my web.xml in the following way: <?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5"> <display-name>PuzzleBazar</display-name>  <welcome-file-list> <welcome-file>Puzzlebazar.html</welcome-file> </welcome-file-list> <filter> <filter-name>guiceFilter</filter-name> <filter-class>com.google.inject.servlet.GuiceFilter</filter-class> </filter> <filter-mapping> <filter-name>guiceFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>  <listener> <listener-class>com.puzzlebazar.server.guice.MyGuiceServletContextListener </listener-class> </listener> </web-app> Since I'm using Guice, I have to configure extra filters in my ServletModule, where I do this: filter("*.html").through( SecurityCookieFilter.class ); But my SecurityCookieFilter.doFilter is never called. I tried things like "*.html*" or <url-pattern>*</url-pattern> but to no avail. Any idea how I should do this?

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Asp.Net MVC2 Model Binding Problem.

- by Pino

Why is my controller recieving an empty model in this case? Using the following, <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<X.Models.ProductModel>" %> <asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server"> <h2>Product</h2> <% using (Html.BeginForm() {%> <%: Html.ValidationSummary(true) %> <div class="editor-label"> Product Name </div> <div class="editor-field"> <%: Html.TextBoxFor(model => model.Name) %> <%: Html.ValidationMessageFor(model => model.Name) %> </div> <br /> <div class="editor-label"> Short Description </div> <div class="editor-field"> <%: Html.TextAreaFor(model => model.ShortDesc) %> <%: Html.ValidationMessageFor(model => model.ShortDesc) %> </div> <br /> <div class="editor-label"> Long Description </div> <div class="editor-field"> <%: Html.TextAreaFor(model => model.LongDesc) %> <%: Html.ValidationMessageFor(model => model.LongDesc) %> </div> <p> <input type="submit" value="Create" /> </p> <% } %> </asp:Content> and the following controller using System.Web.Mvc; using X.Lib.Services; using X.Models; namespace X.Admin.Controllers { public class ProductController : Controller { [HttpGet] public ActionResult ProductData() { return View(); } [HttpPost] public ActionResult ProductData(ProductModel NewProduct) { //Validate and save if(ModelState.IsValid) { //Save And do stuff. var ProductServ = new ProductService(); ProductServ.AddProduct(NewProduct); } return View(); } } }

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Java "compare cannot be resolved to a type" error

- by King Triumph

I'm getting a strange error when attempting to use a comparator with a binary search on an array. The error states that "compareArtist cannot be resolved to a type" and is thrown by Eclipse on this code: Comparator<Song> compare = new Song.compareArtist(); I've done some searching and found references to a possible bug with Eclipse, although I have tried the code on a different computer and the error persists. I've also found similar issues regarding the capitalization of the compare method, in this case compareArtist. I've seen examples where the first word in the method name is capitalized, although it was my understanding that method names are traditionally started with a lower case letter. I have experimented with changing the capitalization but nothing has changed. I have also found references to this error if the class doesn't import the correct package. I have imported java.util in both classes in question, which to my knowledge allows the use of the Comparator. I've experimented with writing the compareArtist method within the class that has the binary search call as well as in the "Song" class, which according to my homework assignment is where it should be. I've changed the constructor accordingly and the issue persists. Lastly, I've attempted to override the Comparator compare method by implementing Comparator in the Song class and creating my own method called "compare". This returns the same error. I've only moved to calling the comparator method something different than "compare" after finding several examples that do the same. Here is the relevant code for the class that calls the binary search that uses the comparator. This code also has a local version of the compareArtist method. While it is not being called currently, the code for this method is the same as the in the class Song, where I am trying to call it from. Thanks for any advice and insight. import java.io.*; import java.util.*; public class SearchByArtistPrefix { private Song[] songs; // keep a direct reference to the song array private Song[] searchResults; // holds the results of the search private ArrayList<Song> searchList = new ArrayList<Song>(); // hold results of search while being populated. Converted to searchResults array. public SearchByArtistPrefix(SongCollection sc) { songs = sc.getAllSongs(); } public int compareArtist (Song firstSong, Song secondSong) { return firstSong.getArtist().compareTo(secondSong.getArtist()); } public Song[] search(String artistPrefix) { String artistInput = artistPrefix; int searchLength = artistInput.length(); Song searchSong = new Song(artistInput, "", ""); Comparator<Song> compare = new Song.compareArtist(); int search = Arrays.binarySearch(songs, searchSong, compare);

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Having to hit the site login button twice after first turning on computer

- by John

Hello, The code below is for a login that I'm using. It works fine, but when I first try logging in after turning on my computer, it only works the second time that I hit the "Login" button. Any idea how I can make it not require hitting the "Login" button twice in this situation? Thanks in advance, John function isLoggedIn() { if (session_is_registered('loginid') && session_is_registered('username')) { return true; // the user is loged in } else { return false; // not logged in } return false; } if (!isLoggedIn()) { if (isset($_POST['cmdlogin'])) { if (checkLogin($_POST['username'], $_POST['password'])) { show_userbox(); } else { echo "Incorrect Login information !"; show_loginform(); } } else { show_loginform(); } } else { show_userbox(); } function show_loginform($disabled = false) { echo '<form name="login-form" id="login-form" method="post" action="./index.php"> <div class="usernameformtext"><label title="Username">Username: </label></div> <div class="usernameformfield"><input tabindex="1" accesskey="u" name="username" type="text" maxlength="30" id="username" /></div> <div class="passwordformtext"><label title="Password">Password: </label></div> <div class="passwordformfield"><input tabindex="2" accesskey="p" name="password" type="password" maxlength="15" id="password" /></div> <div class="registertext"><a href="http://www...com/sandbox/register.php" title="Register">Register</a></div> <div class="lostpasswordtext"><a href="http://www...com/sandbox/lostpassword.php" title="Lost Password">Lost password?</a></div> <p class="loginbutton"><input tabindex="3" accesskey="l" type="submit" name="cmdlogin" value="Login" '; if ($disabled == true) { echo 'disabled="disabled"'; } echo ' /></p></form>'; } EDIT: Here is another function that is used. function isLoggedIn() { if (session_is_registered('loginid') && session_is_registered('username')) { return true; // the user is loged in } else { return false; // not logged in } return false; }

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How to order a HasMany collection by a child property with Fluent NHibernate mapping

- by Geoff Hardy

I am using Fluent NHibernate to map the following classes: public abstract class DomainObject { public virtual int Id { get; protected internal set; } } public class Attribute { public virtual string Name { get; set; } } public class AttributeRule { public virtual Attribute Attribute { get; set; } public virtual Station Station { get; set; } public virtual RuleTypeId RuleTypeId { get; set; } } public class Station : DomainObject { public virtual IList<AttributeRule> AttributeRules { get; set; } public Station() { AttributeRules = new List<AttributeRule>(); } } My Fluent NHibernate mappings look like this: public class AttributeMap : ClassMap<Attribute> { public AttributeMap() { Id(o => o.Id); Map(o => o.Name); } } public class AttributeRuleMap : ClassMap<AttributeRule> { public AttributeRuleMap() { Id(o => o.Id); Map(o => o.RuleTypeId); References(o => o.Attribute).Fetch.Join(); References(o => o.Station); } } public class StationMap : ClassMap<Station> { public StationMap() { Id(o => o.Id); HasMany(o => o.AttributeRules).Inverse(); } } I would like to order the AttributeRules list on Station by the Attribute.Name property, but doing the following does not work: HasMany(o => o.AttributeRules).Inverse().OrderBy("Attribute.Name"); I have not found a way to do this yet in the mappings. I could create a IQuery or ICriteria to do this for me, but ideally I would just like to have the AttributeRules list sorted when I ask for it. Any advice on how to do this mapping?

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Hibernate mapping to object that already exists

- by teehoo

I have two classes, ServiceType and ServiceRequest. Every ServiceRequest must specify what kind of ServiceType it is. All ServiceType's are predefined in the database, and ServiceRequest is created at runtime by the client. Here are my .hbm files: <hibernate-mapping> <class dynamic-insert="false" dynamic-update="false" mutable="true" name="xxx.model.entity.ServiceRequest" optimistic-lock="version" polymorphism="implicit" select-before-update="false"> <id column="USER_ID" name="id"> <generator class="native"/> </id> <property name="quantity"> <column name="quantity" not-null="true"/> </property> <many-to-one cascade="all" class="xxx.model.entity.ServiceType" column="service_type" name="serviceType" not-null="false" unique="false"/> </class> </hibernate-mapping> and <hibernate-mapping> <class dynamic-insert="false" dynamic-update="false" mutable="true" name="xxx.model.entity.ServiceType" optimistic-lock="version" polymorphism="implicit" select-before-update="false"> <id column="USER_ID" name="id"> <generator class="native"/> </id> <property name="description"> <column name="description" not-null="false"/> </property> <property name="cost"> <column name="cost" not-null="true"/> </property> <property name="enabled"> <column name="enabled" not-null="true"/> </property> </class> </hibernate-mapping> When I run this, I get com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails I think my problem is that when I create a new ServiceRequest object, ServiceType is one of its properties, and therefore when I'm saving ServiceRequest to the database, Hibernate attempts to insert the ServiceType object once again, and finds that it is already exists. If this is the case, how do I make it so that Hibernate points to the exists ServiceType instead of trying to insert it again?

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How can I structure my MustacheJS template to add dynamic classes based on the values from a JSON file?

- by JGallardo

OBJECTIVE To build an app that allows the user to search for locations. CURRENT STATE At the moment the locations listed are few, so they are just all presented when landing on the "dealers" page. BACKGROUND Previously there were only about 50 showrooms carrying a product we sell, so a static HTML page was fine. And displays as But the page size grew to about 1500 lines of code after doing this. We have gotten more and need a scalable solution so that we can add many more dealers fast. In other projects, I have previously used MustacheJS and to load in values from a JSON file. I know the ideally this will be an AJAX application. Perhaps I might be better off with database here? Below is what I have in mind so far, and it "works" up to a certain point, but seems not to be anywhere near the most sustainable solution that can be efficiently scaled. HTML <a id="{{state}}"></a> <div> <h4>{{dealer}} : {{city}}, {{state}} {{l_type}}</h4> <div class="{{icon_class}}"> <ul> <li><i class="icon-map-marker"></i></li> <li><i class="icon-phone"></i></li> <li><i class="icon-print"></i></li> </ul> </div> <div class="listingInfo"> <p>{{street}} <br>{{suite}}<br> {{city}}, {{state}} {{zip}}<br> Phone: {{phone}}<br> {{toll_free}}<br> {{fax}} </p> </div> </div> <hr> JSON { "dealers" : [ { "dealer":"Benco Dental", "City":"Denver", "state":"CO", "zip":"80112", "l_type":"Showroom", "icon_class":"listingIcons_3la", "phone":"(303) 790-1421", "toll_free":null, "fax":"(303) 790-1421" }, { "dealer":"Burkhardt Dental Supply", "City":"Portland", "state":"OR", "zip":"97220", "l_type":"Showroom", "icon_class":"listingIcons", "phone":" (503) 252-9777", "toll_free":"(800) 367-3030", "fax":"(866) 408-3488" } ]} CHALLENGES The CSS class wrapping the ul will vary based on how many fields there are. In this case there are 3, so the class is "listingIcons_3la" The "toll free" number section should only show up if in fact, there is a toll free number. the fax number should only show up if there is a value for a fax number.

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Python4Delphi: Returning a python object in a function. (DelphiWrapper)

- by Gabriel Fonseca

I am using python4delphi. ow can I return an object from a wrapped Delphi class function? Code Snippet: I have a simple Delphi Class that i wrapped to Python Script, right? TSimple = Class Private function getvar1:string; Public Published property var1:string read getVar1; function getObj:TSimple; end; ... function TSimple.getVar1:string; begin result:='hello'; end; function TSimple.getObj:TSimple; begin result:=self; end; I made the TPySimple like the demo32 to give class access to the python code. My python module name is test. TPyDado = class(TPyDelphiPersistent) // Constructors & Destructors constructor Create( APythonType : TPythonType ); override; constructor CreateWith( PythonType : TPythonType; args : PPyObject ); override; // Basic services function Repr : PPyObject; override; class function DelphiObjectClass : TClass; override; end; ... { TPyDado } constructor TPyDado.Create(APythonType: TPythonType); begin inherited; // we need to set DelphiObject property DelphiObject := TDado.Create; with TDado(DelphiObject) do begin end; Owned := True; // We own the objects we create end; constructor TPyDado.CreateWith(PythonType: TPythonType; args: PPyObject); begin inherited; with GetPythonEngine, DelphiObject as TDado do begin if PyArg_ParseTuple( args, ':CreateDado' ) = 0 then Exit; end; end; class function TPyDado.DelphiObjectClass: TClass; begin Result := TDado; end; function TPyDado.Repr: PPyObject; begin with GetPythonEngine, DelphiObject as TDado do Result := VariantAsPyObject(Format('',[])); // or Result := PyString_FromString( PAnsiChar(Format('(%d, %d)',[x, y])) ); end; And now the python code: import test a = test.Simple() # try access the property var1 and everything is right print a.var1 # work's, but.. b = a.getObj(); # raise a exception that not find any attributes named getObj. # if the function returns a string for example, it's work.

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How do I change a child's parent in NHibernate when cascade is delete-all-orphan?

- by Daniel T.

I have two entities in a bi-directional one-to-many relationship: public class Storage { public IList<Box> Boxes { get; set; } } public class Box { public Storage CurrentStorage { get; set; } } And the mapping: <class name="Storage"> <bag name="Boxes" cascade="all-delete-orphan" inverse="true"> <key column="Storage_Id" /> <one-to-many class="Box" /> </bag> </class> <class name="Box"> <many-to-one name="CurrentStorage" column="Storage_Id" /> </class> A Storage can have many Boxes, but a Box can only belong to one Storage. I have them mapped so that the one-to-many has a cascade of all-delete-orphan. My problem arises when I try to change a Box's Storage. Assuming I already ran this code: var storage1 = new Storage(); var storage2 = new Storage(); storage1.Boxes.Add(new Box()); Session.Create(storage1); Session.Create(storage2); The following code will give me an exception: // get the first and only box in the DB var existingBox = Database.GetBox().First(); // remove the box from storage1 existingBox.CurrentStorage.Boxes.Remove(existingBox); // add the box to storage2 after it's been removed from storage1 var storage2 = Database.GetStorage().Second(); storage2.Boxes.Add(existingBox); Session.Flush(); // commit changes to DB I get the following exception: NHibernate.ObjectDeletedException : deleted object would be re-saved by cascade (remove deleted object from associations) This exception occurs because I have the cascade set to all-delete-orphan. The first Storage detected that I removed the Box from its collection and marks it for deletion. However, when I added it to the second Storage (in the same session), it attempts to save the box again and the ObjectDeletedException is thrown. My question is, how do I get the Box to change its parent Storage without encountering this exception? I know one possible solution is to change the cascade to just all, but then I lose the ability to have NHibernate automatically delete a Box by simply removing it from a Storage and not re-associating it with another one. Or is this the only way to do it and I have to manually call Session.Delete on the box in order to remove it?

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[Hibernate Mapping] relationship set between table and mapping table to use joins.

- by Matthew De'Loughry

Hi guys, I have two table a "Module" table and a "StaffModule" I'm wanting to display a list of modules by which staff are present on the staffmodule mapping table. I've tried from Module join Staffmodule sm with ID = sm.MID with no luck, I get the following error Path Expected for join! however I thought I had the correct join too allow this but obviously not can any one help StaffModule HBM <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  <hibernate-mapping> <class name="Hibernate.Staffmodule" schema="WALK" table="STAFFMODULE"> <composite-id class="Hibernate.StaffmoduleId" name="id"> <key-many-to-one name="mid" class="Hibernate.Module"> <column name="MID"/> </key-many-to-one> <key-property name="staffid" type="int"> <column name="STAFFID"/> </key-property> </composite-id> </class> </hibernate-mapping> and Module.HBM <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">  <hibernate-mapping> <class name="Hibernate.Module" schema="WALK" table="MODULE"> <id name="id" type="int"> <column name="ID"/> <generator class="assigned"/> </id> <property name="modulename" type="string"> <column length="50" name="MODULENAME"/> </property> <property name="teacherid" type="int"> <column name="TEACHERID" not-null="true"/> </property> </class> hope thats enough information! and thanks in advance.

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C++ vs. C++/CLI: Const qualification of virtual function parameters

- by James McNellis

[All of the following was tested using Visual Studio 2008 SP1] In C++, const qualification of parameter types does not affect the type of a function (8.3.5/3: "Any cv-qualifier modifying a parameter type is deleted") So, for example, in the following class hierarchy, Derived::Foo overrides Base::Foo: struct Base { virtual void Foo(const int i) { } }; struct Derived : Base { virtual void Foo(int i) { } }; Consider a similar hierarchy in C++/CLI: ref class Base abstract { public: virtual void Foo(const int) = 0; }; ref class Derived : public Base { public: virtual void Foo(int i) override { } }; If I then create an instance of Derived: int main(array<System::String ^> ^args) { Derived^ d = gcnew Derived; } it compiles without errors or warnings. When I run it, it throws the following exception and then terminates: An unhandled exception of type 'System.TypeLoadException' occurred in ClrVirtualTest.exe Additional information: Method 'Foo' in type 'Derived'...does not have an implementation. That exception seems to indicate that the const qualification of the parameter does affect the type of the function in C++/CLI (or, at least it affects overriding in some way). However, if I comment out the line containing the definition of Derived::Foo, the compiler reports the following error (on the line in main where the instance of Derived is instantiated): error C2259: 'Derived': cannot instantiate abstract class If I add the const qualifier to the parameter of Derived::Foo or remove the const qualifier from the parameter of Base::Foo, it compiles and runs with no errors. I would think that if the const qualification of the parameter affects the type of the function, I should get this error if the const qualification of the parameter in the derived class virtual function does not match the const qualification of the parameter in the base class virtual function. If I change the type of Derived::Foo's parameter from an int to a double, I get the following warning (in addition to the aforementioned error, C2259): warning C4490: 'override': incorrect use of override specifier; 'Derived::Foo' does not match a base ref class method So, my question is, effectively, does the const qualification of function parameters affect the type of the function in C++/CLI? If so, why does this compile and why are there no errors or warnings? If not, why is an exception thrown?

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Is do-notation specific to "base:GHC.Base.Monad"?

- by yairchu

The idea that the standard Monad class is flawed and that it should actually extend Functor or Pointed is floating around. I'm not necessarily claiming that it is the right thing to do, but suppose that one was trying to do it: import Prelude hiding (Monad(..)) class Functor m => Monad m where return :: a -> m a join :: m (m a) -> m a join = (>>= id) (>>=) :: m a -> (a -> m b) -> m b a >>= t = join (fmap t a) (>>) :: m a -> m b -> m b a >> b = a >>= const b So far so good, but then when trying to use do-notation: whileM :: Monad m => m Bool -> m () whileM iteration = do done <- iteration if done then return () else whileM iteration The compiler complains: Could not deduce (base:GHC.Base.Monad m) from the context (Monad m) Question: Does do-notation work only for base:GHC.Base.Monad? Is there a way to make it work with an alternative Monad class? Extra context: What I really want to do is replace base:Control.Arrow.Arrow with a "generalized" Arrow class: {-# LANGUAGE TypeFamilies #-} class Category a => Arrow a where type Pair a :: * -> * -> * arr :: (b -> c) -> a b c first :: a b c -> a (Pair a b d) (Pair a c d) second :: a b c -> a (Pair a d b) (Pair a d c) (***) :: a b c -> a b' c' -> a (Pair a b b') (Pair a c c') (&&&) :: a b c -> a b c' -> a b (Pair a c c') And then use the Arrow's proc-notation with my Arrow class, but that fails like in the example above of do-notation and Monad. I'll use mostly Either as my pair type constructor and not the (,) type constructor as with the current Arrow class. This might allow to make the code of my toy RTS game (cabal install DefendTheKind) much prettier.

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