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  • spring mvc, css and javascript is not working properly

    - by user2788424
    the css and javascript is not take effect on my page. I google online, people saying this is the magic, but not happening on my page. <mvc:resources mapping="/resources/**" location="/resources/" /> this is the error: Nov 02, 2013 9:19:29 PM org.springframework.web.servlet.DispatcherServlet noHandlerFound WARNING: No mapping found for HTTP request with URI [/myweb/resources/css/styles.css] in DispatcherServlet with name 'dispatcher' Nov 02, 2013 9:19:29 PM org.springframework.web.servlet.DispatcherServlet noHandlerFound WARNING: No mapping found for HTTP request with URI [/myweb/resources/script.js] in DispatcherServlet with name 'dispatcher' Nov 02, 2013 9:19:29 PM org.springframework.web.servlet.DispatcherServlet noHandlerFound WARNING: No mapping found for HTTP request with URI [/myweb/resources/js/jquery-1.10.2.min.js] in DispatcherServlet with name 'dispatcher' here is the applicationContext.xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd"> <context:component-scan base-package="org.peterhuang.myweb" /> <mvc:resources mapping="/resources/**" location="/resources/" /> <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"> </bean> <bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping"> </bean> <!-- Hibernate Transaction Manager --> <bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager"> <property name="sessionFactory" ref="sessionFactory" /> </bean> <mvc:annotation-driven /> <!-- Activates annotation based transaction management --> <tx:annotation-driven /> <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"> <property name="location" value="classpath:jdbc.properties" /> </bean> <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/"></property> <property name="suffix" value=".jsp"></property> </bean> <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="${jdbc.driverClassName}" /> <property name="url" value="${jdbc.url}" /> <property name="username" value="${jdbc.username}" /> <property name="password" value="${jdbc.password}" /> </bean> <bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="packagesToScan" value="org.peterhuang.myweb" /> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect"> ${jdbc.dialect} </prop> <prop key="hibernate.show_sql"> ${hibernate.show_sql} </prop> <prop key="hibernate.format_sql"> ${hibernate.format_sql} </prop> </props> </property> </bean> here is the web.xml <?xml version="1.0" encoding="UTF-8"?> <web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <display-name>my web</display-name> <servlet> <servlet-name>dispatcher</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/applicationContext.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>dispatcher</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <welcome-file-list> <welcome-file>/WEB-INF/jsp/welcome.jsp</welcome-file> </welcome-file-list> this is the page got displaied: <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> <%@ taglib uri="http://www.springframework.org/tags" prefix="spring"%> <link type="text/css" rel="stylesheet" href="<spring:url value='resources/css/styles.css' />" /> <script type="text/javascript" src="<spring:url value='resources/js/jquery-1.10.2.min.js' />"></script> <script type="text/javascript" src="<spring:url value='resources/script.js'/>"</script> <ul id="button"> <c:forEach var="category" items="${categoryList}"> <li><a href="#">${category.categoryName}</a></li> </c:forEach> </ul> the folder structure in eclipse: myweb | | | |----Java Resources | | | | | |-----src/main/resources | | | | | | | | |------js | | | | | | | |-----jquery-1.10.2.min.js | | | | | | | | | | | |-----script.js | | | | | | | | |-----css | | | | | | | |-----style.css | | | | | | | | any tips would be appreciated!! thanks in advanced!

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  • Which programming idiom to choose for this open source library?

    - by Walkman
    I have an interesting question about which programming idiom is easier to use for beginner developers writing concrete file parsing classes. I'm developing an open source library, which one of the main functionality is to parse plain text files and get structured information from them. All of the files contains the same kind of information, but can be in different formats like XML, plain text (each of them is structured differently), etc. There are a common set of information pieces which is the same in all (e.g. player names, table names, some id numbers) There are formats which are very similar to each other, so it's possible to define a common Base class for them to facilitate concrete format parser implementations. So I can clearly define base classes like SplittablePlainTextFormat, XMLFormat, SeparateSummaryFormat, etc. Each of them hints the kind of structure they aim to parse. All of the concrete classes should have the same information pieces, no matter what. To be useful at all, this library needs to define at least 30-40 of these parsers. A couple of them are more important than others (obviously the more popular formats). Now my question is, which is the best programming idiom to choose to facilitate the development of these concrete classes? Let me explain: I think imperative programming is easy to follow even for beginners, because the flow is fixed, the statements just come one after another. Right now, I have this: class SplittableBaseFormat: def parse(self): "Parses the body of the hand history, but first parse header if not yet parsed." if not self.header_parsed: self.parse_header() self._parse_table() self._parse_players() self._parse_button() self._parse_hero() self._parse_preflop() self._parse_street('flop') self._parse_street('turn') self._parse_street('river') self._parse_showdown() self._parse_pot() self._parse_board() self._parse_winners() self._parse_extra() self.parsed = True So the concrete parser need to define these methods in order in any way they want. Easy to follow, but takes longer to implement each individual concrete parser. So what about declarative? In this case Base classes (like SplittableFormat and XMLFormat) would do the heavy lifting based on regex and line/node number declarations in the concrete class, and concrete classes have no code at all, just line numbers and regexes, maybe other kind of rules. Like this: class SplittableFormat: def parse_table(): "Parses TABLE_REGEX and get information" # set attributes here def parse_players(): "parses PLAYER_REGEX and get information" # set attributes here class SpecificFormat1(SplittableFormat): TABLE_REGEX = re.compile('^(?P<table_name>.*) other info \d* etc') TABLE_LINE = 1 PLAYER_REGEX = re.compile('^Player \d: (?P<player_name>.*) has (.*) in chips.') PLAYER_LINE = 16 class SpecificFormat2(SplittableFormat): TABLE_REGEX = re.compile(r'^Tournament #(\d*) (?P<table_name>.*) other info2 \d* etc') TABLE_LINE = 2 PLAYER_REGEX = re.compile(r'^Seat \d: (?P<player_name>.*) has a stack of (\d*)') PLAYER_LINE = 14 So if I want to make it possible for non-developers to write these classes the way to go seems to be the declarative way, however, I'm almost certain I can't eliminate the declarations of regexes, which clearly needs (senior :D) programmers, so should I care about this at all? Do you think it matters to choose one over another or doesn't matter at all? Maybe if somebody wants to work on this project, they will, if not, no matter which idiom I choose. Can I "convert" non-programmers to help developing these? What are your observations? Other considerations: Imperative will allow any kind of work; there is a simple flow, which they can follow but inside that, they can do whatever they want. It would be harder to force a common interface with imperative because of this arbitrary implementations. Declarative will be much more rigid, which is a bad thing, because formats might change over time without any notice. Declarative will be harder for me to develop and takes longer time. Imperative is already ready to release. I hope a nice discussion will happen in this thread about programming idioms regarding which to use when, which is better for open source projects with different scenarios, which is better for wide range of developer skills. TL; DR: Parsing different file formats (plain text, XML) They contains same kind of information Target audience: non-developers, beginners Regex probably cannot be avoided 30-40 concrete parser classes needed Facilitate coding these concrete classes Which idiom is better?

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  • A basic T4 template for generating Model Metadata in ASP.NET MVC2

    - by rajbk
    I have been learning about T4 templates recently by looking at the awesome ADO.NET POCO entity generator. By using the POCO entity generator template as a base, I created a T4 template which generates metadata classes for a given Entity Data Model. This speeds coding by reducing the amount of typing required when creating view specific model and its metadata. To use this template, Download the template provided at the bottom. Set two values in the template file. The first one should point to the EDM you wish to generate metadata for. The second is used to suffix the namespace and classes that get generated. string inputFile = @"Northwind.edmx"; string suffix = "AutoMetadata"; Add the template to your MVC 2 Visual Studio 2010 project. Once you add it, a number of classes will get added to your project based on the number of entities you have.    One of these classes is shown below. Note that the DisplayName, Required and StringLength attributes have been added by the t4 template. //------------------------------------------------------------------------------ // <auto-generated> // This code was generated from a template. // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------   using System; using System.ComponentModel; using System.ComponentModel.DataAnnotations;   namespace NorthwindSales.ModelsAutoMetadata { public partial class CustomerAutoMetadata { [DisplayName("Customer ID")] [Required] [StringLength(5)] public string CustomerID { get; set; } [DisplayName("Company Name")] [Required] [StringLength(40)] public string CompanyName { get; set; } [DisplayName("Contact Name")] [StringLength(30)] public string ContactName { get; set; } [DisplayName("Contact Title")] [StringLength(30)] public string ContactTitle { get; set; } [DisplayName("Address")] [StringLength(60)] public string Address { get; set; } [DisplayName("City")] [StringLength(15)] public string City { get; set; } [DisplayName("Region")] [StringLength(15)] public string Region { get; set; } [DisplayName("Postal Code")] [StringLength(10)] public string PostalCode { get; set; } [DisplayName("Country")] [StringLength(15)] public string Country { get; set; } [DisplayName("Phone")] [StringLength(24)] public string Phone { get; set; } [DisplayName("Fax")] [StringLength(24)] public string Fax { get; set; } } } The gen’d class can be used from your project by creating a partial class with the entity name and setting the MetadataType attribute.namespace MyProject.Models{ [MetadataType(typeof(CustomerAutoMetadata))] public partial class Customer { }} You can also copy the code in the metadata class generated and create your own ViewModel class. Note that the template is super basic  and does not take into account complex properties. I have tested it with the Northwind database. This is a work in progress. Feel free to modify the template to suite your requirements. Standard disclaimer follows: Use At Your Own Risk, Works on my machine running VS 2010 RTM/ASP.NET MVC 2 AutoMetaData.zip Mr. Incredible: Of course I have a secret identity. I don't know a single superhero who doesn't. Who wants the pressure of being super all the time?

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  • SQL SERVER – Transcript of Learning SQL Server Performance: Indexing Basics – Interview of Vinod Kumar by Pinal Dave

    - by pinaldave
    Recently I just wrote a blog post on about Learning SQL Server Performance: Indexing Basics and I received lots of request that if we can share some insight into the course. Here is 200 seconds interview of Vinod Kumar I took right after completing the course. We have few free codes to watch the course, please your comment at http://facebook.com/SQLAuth and we will few of first ones, we will send the code. There are many people who said they would like to read the transcript of the video. Here I have generated the same. Pinal: Vinod, we recently released this course, SQL Server Indexing. It is about performance tuning. So tell me – how do indexes help performance? Vinod: I think what happens in the industry when it comes to performance is that developers and DBAs look at indexes first.  So that’s the first step for any performance tuning exercise, indexing is one of the most critical aspects and it is important to learn it the right way. Pinal: Correct. So what you mean to say is that if you know indexing you can pretty much tune any server and query. Vinod: So I might contradict my false statement now. Indexing is usually a stepping stone but it does not lead you to the end. But it’s good to start with indexing and there are lots of nuances to indexing that you need to understand, like how SQL uses indexing and how performance can improve because of the strategies that you have made. Pinal: But now I’m confused. First you said indexes are good, and then you said that indexes can degrade your performance.  So what is this course about?  I mean how does this course really make an impact? Vinod: Ok -so from the course perspective, what we are trying to do is give you a capsule which gives you a good start. Every journey needs a beginning, you need that first step.  This course is that first step in understanding. This is the most basic, fundamental course that we have tried to attack. This is the fundamentals of indexing, some of the key things that you must know about indexing.   Some of the basics of indexing are lesser known and so I think this course is geared towards each and every one of you out there who wants to understand little bit more about indexing. Pinal: So what I understand is that if I enrolled in this course I will have a minimum understanding about indexing when dealing with performance tuning.  Right? Vinod: Exactly. In this course is we have tried to give you a nice summary. We are talking about clustered indexing, non clustered indexing, too many indexes, too few indexes, over indexing, under indexing, duplicate indexing, columns tune indexing, with SQL Server 2012. There’s lot’s to learn. Pinal: You can see the URL [http://bit.ly/sql-index] of the course on the screen. Go ahead, attend, and let us know what you think about it. Thank you. Vinod: Thank you. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology, Video

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  • Subterranean IL: Pseudo custom attributes

    - by Simon Cooper
    Custom attributes were designed to make the .NET framework extensible; if a .NET language needs to store additional metadata on an item that isn't expressible in IL, then an attribute could be applied to the IL item to represent this metadata. For instance, the C# compiler uses DecimalConstantAttribute and DateTimeConstantAttribute to represent compile-time decimal or datetime constants, which aren't allowed in pure IL, and FixedBufferAttribute to represent fixed struct fields. How attributes are compiled Within a .NET assembly are a series of tables containing all the metadata for items within the assembly; for instance, the TypeDef table stores metadata on all the types in the assembly, and MethodDef does the same for all the methods and constructors. Custom attribute information is stored in the CustomAttribute table, which has references to the IL item the attribute is applied to, the constructor used (which implies the type of attribute applied), and a binary blob representing the arguments and name/value pairs used in the attribute application. For example, the following C# class: [Obsolete("Please use MyClass2", true)] public class MyClass { // ... } corresponds to the following IL class definition: .class public MyClass { .custom instance void [mscorlib]System.ObsoleteAttribute::.ctor(string, bool) = { string('Please use MyClass2' bool(true) } // ... } and results in the following entry in the CustomAttribute table: TypeDef(MyClass) MemberRef(ObsoleteAttribute::.ctor(string, bool)) blob -> {string('Please use MyClass2' bool(true)} However, there are some attributes that don't compile in this way. Pseudo custom attributes Just like there are some concepts in a language that can't be represented in IL, there are some concepts in IL that can't be represented in a language. This is where pseudo custom attributes come into play. The most obvious of these is SerializableAttribute. Although it looks like an attribute, it doesn't compile to a CustomAttribute table entry; it instead sets the serializable bit directly within the TypeDef entry for the type. This flag is fully expressible within IL; this C#: [Serializable] public class MySerializableClass {} compiles to this IL: .class public serializable MySerializableClass {} For those interested, a full list of pseudo custom attributes is available here. For the rest of this post, I'll be concentrating on the ones that deal with P/Invoke. P/Invoke attributes P/Invoke is built right into the CLR at quite a deep level; there are 2 metadata tables within an assembly dedicated solely to p/invoke interop, and many more that affect it. Furthermore, all the attributes used to specify p/invoke methods in C# or VB have their own keywords and syntax within IL. For example, the following C# method declaration: [DllImport("mscorsn.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.U1)] private static extern bool StrongNameSignatureVerificationEx( [MarshalAs(UnmanagedType.LPWStr)] string wszFilePath, [MarshalAs(UnmanagedType.U1)] bool fForceVerification, [MarshalAs(UnmanagedType.U1)] ref bool pfWasVerified); compiles to the following IL definition: .method private static pinvokeimpl("mscorsn.dll" lasterr winapi) bool marshal(unsigned int8) StrongNameSignatureVerificationEx( string marshal(lpwstr) wszFilePath, bool marshal(unsigned int8) fForceVerification, bool& marshal(unsigned int8) pfWasVerified) cil managed preservesig {} As you can see, all the p/invoke and marshal properties are specified directly in IL, rather than using attributes. And, rather than creating entries in CustomAttribute, a whole bunch of metadata is emitted to represent this information. This single method declaration results in the following metadata being output to the assembly: A MethodDef entry containing basic information on the method Four ParamDef entries for the 3 method parameters and return type An entry in ModuleRef to mscorsn.dll An entry in ImplMap linking ModuleRef and MethodDef, along with the name of the function to import and the pinvoke options (lasterr winapi) Four FieldMarshal entries containing the marshal information for each parameter. Phew! Applying attributes Most of the time, when you apply an attribute to an element, an entry in the CustomAttribute table will be created to represent that application. However, some attributes represent concepts in IL that aren't expressible in the language you're coding in, and can instead result in a single bit change (SerializableAttribute and NonSerializedAttribute), or many extra metadata table entries (the p/invoke attributes) being emitted to the output assembly.

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  • ASP.NET MVC for the php/asp noob

    - by dotjosh
    I was talking to a friend today, who's foremost a php developer, about his thoughts on Umbraco and he said "Well they're apparently working feverishly on the new version of Umbraco, which will be MVC... which i still don't know what that means, but I know you like it." I ended up giving him a ground up explanation of ASP.NET MVC, so I'm posting this so he can link this to his friends and for anyone else who finds it useful.  The whole goal was to be as simple as possible, not being focused on proper syntax. Model-View-Controller (or MVC) is just a pattern that is used for handling UI interaction with your backend.  In a typical web app, you can imagine the *M*odel as your database model, the *V*iew as your HTML page, and the *C*ontroller as the class inbetween.  MVC handles your web request different than your typical php/asp app.In your php/asp app, your url maps directly to a php/asp file that contains html, mixed with database access code and redirects.In an MVC app, your url route is mapped to a method on a class (the controller).  The body of this method can do some database access and THEN decide which *V*iew (html/aspx page) should be displayed;  putting the controller in charge and not the view... a clear seperation of concerns that provides better reusibility and generally promotes cleaner code. Mysite.com, a quick example:Let's say you hit the following url in your application: http://www.mysite.com/Product/ShowItem?Id=4 To avoid tedious configuration, MVC uses a lot of conventions by default. For instance, the above url in your app would automatically make MVC search for a .net class with the name "Product" and a method named "ShowItem" based on the pattern of the url.  So if you name things properly, your method would automatically be called when you entered the above url.  Additionally, it would automatically map/hydrate the "int id" parameter that was in your querystring, matched by name.Product.cspublic class Product : Controller{    public ViewResult ShowItem(int id)    {        return View();    }} From this point you can write the code in the body of this method to do some database access and then pass a "bag" (also known as the ViewData) of data to your chosen *V*iew (html page) to use for display.  The view(html) ONLY needs to be worried about displaying the flattened data that it's been given in the best way it can;  this allows the view to be reused throughout your application as *just* a view, and not be coupled to HOW the data for that view get's loaded.. Product.cspublic class Product : Controller{    public ViewResult ShowItem(int id)    {        var database = new Database();        var item = database.GetItem(id);        ViewData["TheItem"] = item;        return View();    }} Again by convention, since the class' method name is "ShowItem", it'll search for a view named "ShowItem.aspx" by default, and pass the ViewData bag to it to use. ShowItem.aspx<html>     <body>      <%        var item =(Item)ViewData["TheItem"]       %>       <h1><%= item.FullProductName %></h1>     </body></html> BUT WAIT! WHY DOES MICROSOFT HAVE TO DO THINGS SO DIFFERENTLY!?They aren't... here are some other frameworks you may have heard of that use the same pattern in a their own way: Ruby On Rails Grails Spring MVC Struts Django    

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  • Extended Logging with Caller Info Attributes

    - by João Angelo
    .NET 4.5 caller info attributes may be one of those features that do not get much airtime, but nonetheless are a great addition to the framework. These attributes will allow you to programmatically access information about the caller of a given method, more specifically, the code file full path, the member name of the caller and the line number at which the method was called. They are implemented by taking advantage of C# 4.0 optional parameters and are a compile time feature so as an added bonus the returned member name is not affected by obfuscation. The main usage scenario will be for tracing and debugging routines as will see right now. In this sample code I’ll be using NLog, but the example is also applicable to other logging frameworks like log4net. First an helper class, without any dependencies and that can be used anywhere to obtain caller information: using System; using System.IO; using System.Runtime.CompilerServices; public sealed class CallerInfo { private CallerInfo(string filePath, string memberName, int lineNumber) { this.FilePath = filePath; this.MemberName = memberName; this.LineNumber = lineNumber; } public static CallerInfo Create( [CallerFilePath] string filePath = "", [CallerMemberName] string memberName = "", [CallerLineNumber] int lineNumber = 0) { return new CallerInfo(filePath, memberName, lineNumber); } public string FilePath { get; private set; } public string FileName { get { return this.fileName ?? (this.fileName = Path.GetFileName(this.FilePath)); } } public string MemberName { get; private set; } public int LineNumber { get; private set; } public override string ToString() { return string.Concat(this.FilePath, "|", this.MemberName, "|", this.LineNumber); } private string fileName; } Then an extension class specific for NLog Logger: using System; using System.Runtime.CompilerServices; using NLog; public static class LoggerExtensions { public static void TraceMemberEntry( this Logger logger, [CallerFilePath] string filePath = "", [CallerMemberName] string memberName = "", [CallerLineNumber] int lineNumber = 0) { LogMemberEntry(logger, LogLevel.Trace, filePath, memberName, lineNumber); } public static void TraceMemberExit( this Logger logger, [CallerFilePath] string filePath = "", [CallerMemberName] string memberName = "", [CallerLineNumber] int lineNumber = 0) { LogMemberExit(logger, LogLevel.Trace, filePath, memberName, lineNumber); } public static void DebugMemberEntry( this Logger logger, [CallerFilePath] string filePath = "", [CallerMemberName] string memberName = "", [CallerLineNumber] int lineNumber = 0) { LogMemberEntry(logger, LogLevel.Debug, filePath, memberName, lineNumber); } public static void DebugMemberExit( this Logger logger, [CallerFilePath] string filePath = "", [CallerMemberName] string memberName = "", [CallerLineNumber] int lineNumber = 0) { LogMemberExit(logger, LogLevel.Debug, filePath, memberName, lineNumber); } public static void LogMemberEntry( this Logger logger, LogLevel logLevel, [CallerFilePath] string filePath = "", [CallerMemberName] string memberName = "", [CallerLineNumber] int lineNumber = 0) { const string MsgFormat = "Entering member {1} at line {2}"; InternalLog(logger, logLevel, MsgFormat, filePath, memberName, lineNumber); } public static void LogMemberExit( this Logger logger, LogLevel logLevel, [CallerFilePath] string filePath = "", [CallerMemberName] string memberName = "", [CallerLineNumber] int lineNumber = 0) { const string MsgFormat = "Exiting member {1} at line {2}"; InternalLog(logger, logLevel, MsgFormat, filePath, memberName, lineNumber); } private static void InternalLog( Logger logger, LogLevel logLevel, string format, string filePath, string memberName, int lineNumber) { if (logger == null) throw new ArgumentNullException("logger"); if (logLevel == null) throw new ArgumentNullException("logLevel"); logger.Log(logLevel, format, filePath, memberName, lineNumber); } } Finally an usage example: using NLog; internal static class Program { private static readonly Logger Logger = LogManager.GetCurrentClassLogger(); private static void Main(string[] args) { Logger.TraceMemberEntry(); // Compile time feature // Next three lines output the same except for line number Logger.Trace(CallerInfo.Create().ToString()); Logger.Trace(() => CallerInfo.Create().ToString()); Logger.Trace(delegate() { return CallerInfo.Create().ToString(); }); Logger.TraceMemberExit(); } } NOTE: Code for helper class and Logger extension also available here.

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  • Stretch in multiple components using af:popup, af:region, af:panelTabbed

    - by Arvinder Singh
    Case study: I have a pop-up(dialogue) that contains a region(separate taskflow) showing a tab. The contents of this tab is in a region having a separate taskflow. The jsff page of this taskflow contains a panelSplitter which in turn contains a table. In short the components are : pop-up(dialogue) --> region(separate taskflow) --> tab --> region(separate taskflow) --> panelSplitter --> table At times the tab is not displayed with 100% width or the table in panelSplitter is not 100% visible or the splitter is not visible. Maintaining the stretch for all the components is difficult......not any more!!! Below is the solution that you can make use of in many similar scenarios. I am mentioning the major code snippets affecting the stretch and alignment. pop-up: <af:popup> <af:dialog id="d2" type="none" title="" inlineStyle="width:1200px"> <af:region value="#{bindings.PriceChangePopupFlow1.regionModel}" id="r1"/> </af:dialog> The above region is a jsff containing multiple tabs. I am showing code for a single tab. I kept the tab in a panelStretchLayout. <af:panelStretchLayout id="psl1" topHeight="300px" styleClass="AFStretchWidth"> <af:panelTabbed id="pt1"> <af:showDetailItem text="PO Details" id="sdi1" stretchChildren="first" > <af:region value="#{bindings.PriceChangePurchaseOrderFlow1.regionModel}" id="r1" binding="# {pageFlowScope.priceChangePopupBean.poDetailsRegion}" /> This "region" displays a .jsff containing a table in a panelSplitter. <af:panelSplitter id="ps1"  orientation="horizontal" splitterPosition="700"> <f:facet name="first"> <af:panelHeader text="PurchaseOrder" id="ph1"> <af:table id="md1" rows="#{bindings.PurchaseOrderVO.rangeSize}" That's it!!! We're done... Note the stretchChildren="first" attribute in the af:showDetailItem. That does the trick for us. Oracle docs say the following about stretchChildren :  Valid Values: none, first The stretching behavior for children. Acceptable values include: "none": does not attempt to stretch any children (the default value and the value you need to use if you have more than a single child; also the value you need to use if the child does not support being stretched) "first": stretches the first child (not to be used if you have multiple children as such usage will produce unreliable results; also not to be used if the child does not support being stretched)

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  • Is there a good [and modern] reason to not have static HTML pages with AJAX content , rather than generate pages?

    - by user1725
    Assumptions: We don't care about IE6, and Noscript users. Lets pretend we have the following design concept: All your pages are HTML/CSS that create the ascetics, layout, colours, general design related things. Lets pretend this basic code below is that: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html> <head> <link href="/example.css" rel="stylesheet" type="text/css"/> <script src="example.js" type="text/javascript"></script> <head> <body> <div class="left"> </div> <div class="mid"> </div> <div class="right"> </div> </body> </html> Which in theory should produce, with the right CSS, three vertical columns on the web page. Now, here's the root of the question, what are the serious advantages and/or disadvantages of loading the content of these columns (lets assume they are all indeed dynamic content, not static) via AJAX requests, or have the content pre-set with a scripting language? So for instance, we would have, in the AJAX example, lets asume jquery is used on-load: //Multiple http requests $("body > div.left").load("./script.php?content=news"); $("body > div.right").load("./script.php?content=blogs"); $("body > div.mid").load("./script.php?content=links"); OR--- //Single http request $.ajax({ url: './script.php?content=news|blogs|links', method: 'json', type: 'text', success: function (data) { $("body > div.left").html(data.news); $("body > div.right").html(data.blogs); $("body > div.mid").html(data.links); } }) Verses doing this: <body> <div class="left"> <?php echo function_returning_news(); ?> </div> <div class="mid"> <?php echo function_returning_blogs(); ?> </div> <div class="right"> <?php echo function_returning_links(); ?> </div> </body> I'm personally thinking right now that doing static HTML pages is a better method, my reasoning is: I've separated my data, logic, and presentation (ie, "MVC") code. I can make changes to one without others. Browser caches mean I'm just getting server load mostly for the content, not the presentation wrapped around it. I could turn my "script.php" into a more robust API for the website. But I'm not certain or clear that these are legitimately good reasons, and I'm not confidently aware of other issues that could happen, so I would like to know the pros-and-cons, so to speak.

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  • JDK 7u25: Solutions to Issues caused by changes to Runtime.exec

    - by Devika Gollapudi
    The following examples were prepared by Java engineering for the benefit of Java developers who may have faced issues with Runtime.exec on the Windows platform. Background In JDK 7u21, the decoding of command strings specified to Runtime.exec(String), Runtime.exec(String,String[]) and Runtime.exec(String,String[],File) methods, has been made more strict. See JDK 7u21 Release Notes for more information. This caused several issues for applications. The following section describes some of the problems faced by developers and their solutions. Note: In JDK 7u25, the system property jdk.lang.Process.allowAmbigousCommands can be used to relax the checking process and helps as a workaround for some applications that cannot be changed. The workaround is only effective for applications that are run without a SecurityManager. See JDK 7u25 Release Notes for more information. Note: To understand the details of the Windows API CreateProcess call, see: http://msdn.microsoft.com/en-us/library/windows/desktop/ms682425%28v=vs.85%29.aspx There are two forms of Runtime.exec calls: with the command as string: "Runtime.exec(String command[, ...])" with the command as string array: "Runtime.exec(String[] cmdarray [, ...] )" The issues described in this section relate to the first form of call. With the first call form, developers expect the command to be passed "as is" to Windows where the command needs be split into its executable name and arguments parts first. But, in accordance with Java API, the command argument is split into executable name and arguments by spaces. Problem 1: "The file path for the command includes spaces" In the call: Runtime.getRuntime().exec("c:\\Program Files\\do.exe") the argument is split by spaces to an array of strings as: c:\\Program, Files\\do.exe The first element of parsed array is interpreted as the executable name, verified by SecurityManager (if present) and surrounded by quotations to avoid ambiguity in executable path. This results in the wrong command: "c:\\Program" "Files\\do.exe" which will fail. Solution: Use the ProcessBuilder class, or the Runtime.exec(String[] cmdarray [, ...] ) call, or quote the executable path. Where it is not possible to change the application code and where a SecurityManager is not used, the Java property jdk.lang.Process.allowAmbigousCommands could be used by setting its value to "true" from the command line: -Djdk.lang.Process.allowAmbigousCommands=true This will relax the checking process to allow ambiguous input. Examples: new ProcessBuilder("c:\\Program Files\\do.exe").start() Runtime.getRuntime().exec(new String[]{"c:\\Program Files\\do.exe"}) Runtime.getRuntime().exec("\"c:\\Program Files\\do.exe\"") Problem 2: "Shell command/.bat/.cmd IO redirection" The following implicit cmd.exe calls: Runtime.getRuntime().exec("dir temp.txt") new ProcessBuilder("foo.bat", "", "temp.txt").start() Runtime.getRuntime().exec(new String[]{"foo.cmd", "", "temp.txt"}) lead to the wrong command: "XXXX" "" temp.txt Solution: To specify the command correctly, use the following options: Runtime.getRuntime().exec("cmd /C \"dir temp.txt\"") new ProcessBuilder("cmd", "/C", "foo.bat temp.txt").start() Runtime.getRuntime().exec(new String[]{"cmd", "/C", "foo.cmd temp.txt"}) or Process p = new ProcessBuilder("cmd", "/C" "XXX").redirectOutput(new File("temp.txt")).start(); Problem 3: "Group execution of shell command and/or .bat/.cmd files" Due to enforced verification procedure, arguments in the following calls create the wrong commands.: Runtime.getRuntime().exec("first.bat && second.bat") new ProcessBuilder("dir", "&&", "second.bat").start() Runtime.getRuntime().exec(new String[]{"dir", "|", "more"}) Solution: To specify the command correctly, use the following options: Runtime.exec("cmd /C \"first.bat && second.bat\"") new ProcessBuilder("cmd", "/C", "dir && second.bat").start() Runtime.exec(new String[]{"cmd", "/C", "dir | more"}) The same scenario also works for the "&", "||", "^" operators of the cmd.exe shell. Problem 4: ".bat/.cmd with special DOS chars in quoted params” Due to enforced verification, arguments in the following calls will cause exceptions to be thrown.: Runtime.getRuntime().exec("log.bat \"error new ProcessBuilder("log.bat", "error Runtime.getRuntime().exec(new String[]{"log.bat", "error Solution: To specify the command correctly, use the following options: Runtime.getRuntime().exec("cmd /C log.bat \"error new ProcessBuilder("cmd", "/C", "log.bat", "error Runtime.getRuntime().exec(new String[]{"cmd", "/C", "log.bat", "error Examples: Complicated redirection for shell construction: cmd /c dir /b C:\ "my lovely spaces.txt" becomes Runtime.getRuntime().exec(new String[]{"cmd", "/C", "dir \b \"my lovely spaces.txt\"" }); The Golden Rule: In most cases, cmd.exe has two arguments: "/C" and the command for interpretation.

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  • Browser Specific Extensions of HttpClient

    - by imran_ku07
            Introduction:                     REpresentational State Transfer (REST) causing/leaving a great impact on service/API development because it offers a way to access a service without requiring any specific library by embracing HTTP and its features. ASP.NET Web API makes it very easy to quickly build RESTful HTTP services. These HTTP services can be consumed by a variety of clients including browsers, devices, machines, etc. With .NET Framework 4.5, we can use HttpClient class to consume/send/receive RESTful HTTP services(for .NET Framework 4.0, HttpClient class is shipped as part of ASP.NET Web API). The HttpClient class provides a bunch of helper methods(for example, DeleteAsync, PostAsync, GetStringAsync, etc.) to consume a HTTP service very easily. ASP.NET Web API added some more extension methods(for example, PutAsJsonAsync, PutAsXmlAsync, etc) into HttpClient class to further simplify the usage. In addition, HttpClient is also an ideal choice for writing integration test for a RESTful HTTP service. Since a browser is a main client of any RESTful API, it is also important to test the HTTP service on a variety of browsers. RESTful service embraces HTTP headers and different browsers send different HTTP headers. So, I have created a package that will add overloads(with an additional Browser parameter) for almost all the helper methods of HttpClient class. In this article, I will show you how to use this package.           Description:                     Create/open your test project and install ImranB.SystemNetHttp.HttpClientExtensions NuGet package. Then, add this using statement on your class, using ImranB.SystemNetHttp;                     Then, you can start using any HttpClient helper method which include the additional Browser parameter. For example,  var client = new HttpClient(myserver); var task = client.GetAsync("http://domain/myapi", Browser.Chrome); task.Wait(); var response = task.Result; .                     Here is the definition  of Browser, public enum Browser { Firefox = 0, Chrome = 1, IE10 = 2, IE9 = 3, IE8 = 4, IE7 = 5, IE6 = 6, Safari = 7, Opera = 8, Maxthon = 9, }                     These extension methods will make it very easy to write browser specific integration test. It will also help HTTP service consumer to mimic the request sending behavior of a browser. This package source is available on github. So, you can grab the source and add some additional behavior on the top of these extensions.         Summary:                     Testing a REST API is an important aspect of service development and today, testing with a browser is crucial. In this article, I showed how to write integration test that will mimic the browser request sending behavior. I also showed an example. Hopefully you will enjoy this article too.

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  • How should an object that uses composition set its composed components?

    - by Casey
    After struggling with various problems and reading up on component-based systems and reading Bob Nystrom's excellent book "Game Programming Patterns" and in particular the chapter on Components I determined that this is a horrible idea: //Class intended to be inherited by all objects. Engine uses Objects exclusively. class Object : public IUpdatable, public IDrawable { public: Object(); Object(const Object& other); Object& operator=(const Object& rhs); virtual ~Object() =0; virtual void SetBody(const RigidBodyDef& body); virtual const RigidBody* GetBody() const; virtual RigidBody* GetBody(); //Inherited from IUpdatable virtual void Update(double deltaTime); //Inherited from IDrawable virtual void Draw(BITMAP* dest); protected: private: }; I'm attempting to refactor it into a more manageable system. Mr. Nystrom uses the constructor to set the individual components; CHANGING these components at run-time is impossible. It's intended to be derived and be used in derivative classes or factory methods where their constructors do not change at run-time. i.e. his Bjorne object is just a call to a factory method with a specific call to the GameObject constructor. Is this a good idea? Should the object have a default constructor and setters to facilitate run-time changes or no default constructor without setters and instead use a factory method? Given: class Object { public: //...See below for constructor implementation concerns. Object(const Object& other); Object& operator=(const Object& rhs); virtual ~Object() =0; //See below for Setter concerns IUpdatable* GetUpdater(); IDrawable* GetRenderer(); protected: IUpdatable* _updater; IDrawable* _renderer; private: }; Should the components be read-only and passed in to the constructor via: class Object { public: //No default constructor. Object(IUpdatable* updater, IDrawable* renderer); //...remainder is same as above... }; or Should a default constructor be provided and then the components can be set at run-time? class Object { public: Object(); //... SetUpdater(IUpdater* updater); SetRenderer(IDrawable* renderer); //...remainder is same as above... }; or both? class Object { public: Object(); Object(IUpdater* updater, IDrawable* renderer); //... SetUpdater(IUpdater* updater); SetRenderer(IDrawable* renderer); //...remainder is same as above... };

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  • How do I use setFilmSize in panda3d to achieve the correct view?

    - by lhk
    I'm working with Panda3d and recently switched my game to isometric rendering. I moved the virtual camera accordingly and set an orthographic lens. Then I implemented the classes "Map" and "Canvas". A canvas is a dynamically generated mesh: a flat quad. I'm using it to render the ingame graphics. Since the game itself is still set in a 3d coordinate system I'm planning to rely on these canvases to draw sprites. I could have named this class "Tile" but as I'd like to use it for non-tile sketches (enemies, environment) as well I thought canvas would describe it's function better. Map does exactly what it's name suggests. Its constructor receives the number of rows and columns and then creates a standard isometric map. It uses the canvas class for tiles. I'm planning to write a map importer that reads a file to create maps on the fly. Here's the canvas implementation: class Canvas: def __init__(self, texture, vertical=False, width=1,height=1): # create the mesh format=GeomVertexFormat.getV3t2() format = GeomVertexFormat.registerFormat(format) vdata=GeomVertexData("node-vertices", format, Geom.UHStatic) vertex = GeomVertexWriter(vdata, 'vertex') texcoord = GeomVertexWriter(vdata, 'texcoord') # add the vertices for a flat quad vertex.addData3f(1, 0, 0) texcoord.addData2f(1, 0) vertex.addData3f(1, 1, 0) texcoord.addData2f(1, 1) vertex.addData3f(0, 1, 0) texcoord.addData2f(0, 1) vertex.addData3f(0, 0, 0) texcoord.addData2f(0, 0) prim = GeomTriangles(Geom.UHStatic) prim.addVertices(0, 1, 2) prim.addVertices(2, 3, 0) self.geom = Geom(vdata) self.geom.addPrimitive(prim) self.node = GeomNode('node') self.node.addGeom(self.geom) # this is the handle for the canvas self.nodePath=NodePath(self.node) self.nodePath.setSx(width) self.nodePath.setSy(height) if vertical: self.nodePath.setP(90) # the most important part: "Drawing" the image self.texture=loader.loadTexture(""+texture+".png") self.nodePath.setTexture(self.texture) Now the code for the Map class class Map: def __init__(self,rows,columns,size): self.grid=[] for i in range(rows): self.grid.append([]) for j in range(columns): # create a canvas for the tile. For testing the texture is preset tile=Canvas(texture="../assets/textures/flat_concrete",width=size,height=size) x=(i-1)*size y=(j-1)*size # set the tile up for rendering tile.nodePath.reparentTo(render) tile.nodePath.setX(x) tile.nodePath.setY(y) # and store it for later access self.grid[i].append(tile) And finally the usage def loadMap(self): self.map=Map(10, 10, 1) this function is called within the constructor of the World class. The instantiation of world is the entry point to the execution. The code is pretty straightforward and runs good. Sadly the output is not as expected: Please note: The problem is not the white rectangle, it's my player object. The problem is that although the map should have equal width and height it's stretched weirdly. With orthographic rendering I expected the map to be a perfect square. What did I do wrong ? UPDATE: I've changed the viewport. This is how I set up the orthographic camera: lens = OrthographicLens() lens.setFilmSize(40, 20) base.cam.node().setLens(lens) You can change the "aspect" by modifying the parameters of setFilmSize. I don't know exactly how they are related to window size and screen resolution but after testing a little the values above seem to work for me. Now everything is rendered correctly as long as I don't resize the window. Every change of the window's size as well as switching to fullscreen destroys the correct rendering. I know that implementing a listener for resize events is not in the scope of this question. However I wonder why I need to make the Film's height two times bigger than its width. My window is quadratic ! Can you tell me how to find out correct setting for the FilmSize ? UPDATE 2: I can imagine that it's hard to envision the behaviour of the game. At first glance the obvious solution is to pass the window's width and height in pixels to setFilmSize. There are two problems with that approach. The parameters for setFilmSize are ingame units. You'll get a way to big view if you pass the pixel size For some strange reason the image is distorted if you pass equal values for width and height. Here's the output for setFilmSize(800,800) You'll have to stress your eyes but you'll see what I mean

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  • How-to remove the close icon from task flows opened in dialogs (11.1.1.4)

    - by frank.nimphius
    Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} ADF bounded task flows can be opened in an external dialog and return values to the calling application as documented in chapter 19 of Oracle Fusion Middleware Fusion Developer's Guide for Oracle Application Development Framework11g: http://download.oracle.com/docs/cd/E17904_01/web.1111/b31974/taskflows_dialogs.htm#BABBAFJB   Setting the task flow call activity property Run as Dialog to true and the Display Type property to inline-popup opens the bounded task flow in an inline popup. To launch the dialog, a command item is used that references the control flow case to the task flow call activity <af:commandButton text="Lookup" id="cb6"         windowEmbedStyle="inlineDocument" useWindow="true"         windowHeight="300" windowWidth="300"         action="lookup" partialSubmit="true"/> By default, the dialog opens with a close icon in its header that does not raise a task flow return event when used for dismissing the dialog. In previous releases, the close icon could only be hidden using CSS in a custom skin definition, as explained in a previous OTN Harvest publishing (12/2010) http://www.oracle.com/technetwork/developer-tools/adf/learnmore/dec2010-otn-harvest-199274.pdf As a new feature, Oracle JDeveloper 11g (11.1.1.4) provides an option to globally remove the close icon from inline dialogs without using CSS. For this, the following managed bean definition needs to be added to the adfc-config.xml file. <managed-bean>   <managed-bean-name>     oracle$adfinternal$view$rich$dailogInlineDocument   </managed-bean-name>   <managed-bean-class>java.util.TreeMap</managed-bean-class>   <managed-bean-scope>application</managed-bean-scope>     <map-entries>       <key-class>java.lang.String</key-class>       <value-class>java.lang.String</value-class>       <map-entry>         <key>MODE</key>         <value>withoutCancel</value>       </map-entry>     </map-entries>   </managed-bean> Note the setting of the managed bean scope to be application which applies this setting to all sessions of an application.

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  • Question on the implementation of my Entity System

    - by miguel.martin
    I am currently creating an Entity System, in C++, it is almost completed (I have all the code there, I just have to add a few things and test it). The only thing is, I can't figure out how to implement some features. This Entity System is based off a bit from the Artemis framework, however it is different. I'm not sure if I'll be able to type this out the way my head processing it. I'm going to basically ask whether I should do something over something else. Okay, now I'll give a little detail on my Entity System itself. Here are the basic classes that my Entity System uses to actually work: Entity - An Id (and some methods to add/remove/get/etc Components) Component - An empty abstract class ComponentManager - Manages ALL components for ALL entities within a Scene EntitySystem - Processes entities with specific components Aspect - The class that is used to help determine what Components an Entity must contain so a specific EntitySystem can process it EntitySystemManager - Manages all EntitySystems within a Scene EntityManager - Manages entities (i.e. holds all Entities, used to determine whether an Entity has been changed, enables/disables them, etc.) EntityFactory - Creates (and destroys) entities and assigns an ID to them Scene - Contains an EntityManager, EntityFactory, EntitySystemManager and ComponentManager. Has functions to update and initialise the scene. Now in order for an EntitySystem to efficiently know when to check if an Entity is valid for processing (so I can add it to a specific EntitySystem), it must recieve a message from the EntityManager (after a call of activate(Entity& e)). Similarly the EntityManager must know when an Entity is destroyed from the EntityFactory in the Scene, and also the ComponentManager must know when an Entity is created AND destroyed. I do have a Listener/Observer pattern implemented at the moment, but with this pattern I may remove a Listener (which is this case is dependent on the method being called). I mainly have this implemented for specific things related to a game, i.e. Teams, Tagging of entities, etc. So... I was thinking maybe I should call a private method (using friend classes) to send out when an Entity has been activated, deleted, etc. i.e. taken from my EntityFactory void EntityFactory::killEntity(Entity& e) { // if the entity doesn't exsist in the entity manager within the scene if(!getScene()->getEntityManager().doesExsist(e)) { return; // go back to the caller! (should throw an exception or something..) } // tell the ComponentManager and the EntityManager that we killed an Entity getScene()->getComponentManager().doOnEntityWillDie(e); getScene()->getEntityManager().doOnEntityWillDie(e); // notify the listners for(Mouth::iterator i = getMouth().begin(); i != getMouth().end(); ++i) { (*i)->onEntityWillDie(*this, e); } _idPool.addId(e.getId()); // add the ID to the pool delete &e; // delete the entity } As you can see on the lines where I am telling the ComponentManager and the EntityManager that an Entity will die, I am calling a method to make sure it handles it appropriately. Now I realise I could do this without calling it explicitly, with the help of that for loop notifying all listener objects connected to the EntityFactory's Mouth (an object used to tell listeners that there's an event), however is this a good idea (good design, or what)? I've gone over the PROS and CONS, I just can't decide what I want to do. Calling Explicitly: PROS Faster? Since these functions are explicitly called, they can't be "removed" CONS Not flexible Bad design? (friend functions) Calling through Listener objects (i.e. ComponentManager/EntityManager inherits from a EntityFactoryListener) PROS More Flexible? Better Design? CONS Slower? (virtual functions) Listeners can be removed, i.e. may be removed and not get called again during the program, which could cause in a crash. P.S. If you wish to view my current source code, I am hosting it on BitBucket.

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  • Roles / Profiles / Perspectives in NetBeans IDE 7.1

    - by Geertjan
    With a check out of main-silver from yesterday, I'm able to use the brand new "role" attribute in @TopComponent.Registration, as you can see below, in the bit in bold: @ConvertAsProperties(dtd = "-//org.role.demo.ui//Admin//EN", autostore = false) @TopComponent.Description(preferredID = "AdminTopComponent", //iconBase="SET/PATH/TO/ICON/HERE", persistenceType = TopComponent.PERSISTENCE_ALWAYS) @TopComponent.Registration(mode = "editor", openAtStartup = true, role="admin") public final class AdminTopComponent extends TopComponent { And here's a window for general users of the application, with the "role" attribute set to "user": @ConvertAsProperties(dtd = "-//org.role.demo.ui//User//EN", autostore = false) @TopComponent.Description(preferredID = "UserTopComponent", //iconBase="SET/PATH/TO/ICON/HERE", persistenceType = TopComponent.PERSISTENCE_ALWAYS) @TopComponent.Registration(mode = "explorer", openAtStartup = true, role="user") public final class UserTopComponent extends TopComponent { So, I have two windows. One is assigned to the "admin" role, the other to the "user" role. In the "ModuleInstall" class, I add a "WindowSystemListener" and set "user" as the application's role: public class Installer extends ModuleInstall implements WindowSystemListener { @Override public void restored() { WindowManager.getDefault().addWindowSystemListener(this); } @Override public void beforeLoad(WindowSystemEvent event) { WindowManager.getDefault().setRole("user"); WindowManager.getDefault().removeWindowSystemListener(this); } @Override public void afterLoad(WindowSystemEvent event) { } @Override public void beforeSave(WindowSystemEvent event) { } @Override public void afterSave(WindowSystemEvent event) { } } So, when the application starts, the "UserTopComponent" is shown, not the "AdminTopComponent". Next, I have two Actions, for switching between the two roles, as shown below: @ActionID(category = "Window", id = "org.role.demo.ui.SwitchToAdminAction") @ActionRegistration(displayName = "#CTL_SwitchToAdminAction") @ActionReferences({ @ActionReference(path = "Menu/Window", position = 250) }) @Messages("CTL_SwitchToAdminAction=Switch To Admin") public final class SwitchToAdminAction extends AbstractAction { @Override public void actionPerformed(ActionEvent e) { WindowManager.getDefault().setRole("admin"); } @Override public boolean isEnabled() { return !WindowManager.getDefault().getRole().equals("admin"); } } @ActionID(category = "Window", id = "org.role.demo.ui.SwitchToUserAction") @ActionRegistration(displayName = "#CTL_SwitchToUserAction") @ActionReferences({ @ActionReference(path = "Menu/Window", position = 250) }) @Messages("CTL_SwitchToUserAction=Switch To User") public final class SwitchToUserAction extends AbstractAction { @Override public void actionPerformed(ActionEvent e) { WindowManager.getDefault().setRole("user"); } @Override public boolean isEnabled() { return !WindowManager.getDefault().getRole().equals("user"); } } When I select one of the above actions, the role changes, and the other window is shown. I could, of course, add a Login dialog to the "SwitchToAdminAction", so that authentication is required in order to switch to the "admin" role. Now, let's say I am now in the "user" role. So, the "UserTopComponent" shown above is now opened. I decide to also open another window, the Properties window, as below... ...and, when I am in the "admin" role, when the "AdminTopComponent" is open, I decide to also open the Output window, as below... Now, when I switch from one role to the other, the additional window/s I opened will also be opened, together with the explicit members of the currently selected role. And, the main window position and size are also persisted across roles. When I look in the "build" folder of my project in development, I see two different Windows2Local folders, one per role, automatically created by the fact that there is something to be persisted for a particular role, e.g., when a switch to a different role is done: And, with that, we now clearly have roles/profiles/perspectives in NetBeans Platform applications from NetBeans Platform 7.1 onwards.

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  • How should I plan the inheritance structure for my game?

    - by Eric Thoma
    I am trying to write a platform shooter in C++ with a really good class structure for robustness. The game itself is secondary; it is the learning process of writing it that is primary. I am implementing an inheritance tree for all of the objects in my game, but I find myself unsure on some decisions. One specific issue that it bugging me is this: I have an Actor that is simply defined as anything in the game world. Under Actor is Character. Both of these classes are abstract. Under Character is the Philosopher, who is the main character that the user commands. Also under Character is NPC, which uses an AI module with stock routines for friendly, enemy and (maybe) neutral alignments. So under NPC I want to have three subclasses: FriendlyNPC, EnemyNPC and NeutralNPC. These classes are not abstract, and will often be subclassed in order to make different types of NPC's, like Engineer, Scientist and the most evil Programmer. Still, if I want to implement a generic NPC named Kevin, it would nice to be able to put him in without making a new class for him. I could just instantiate a FriendlyNPC and pass some values for the AI machine and for the dialogue; that would be ideal. But what if Kevin is the one benevolent Programmer in the whole world? Now we must make a class for him (but what should it be called?). Now we have a character that should inherit from Programmer (as Kevin has all the same abilities but just uses the friendly AI functions) but also should inherit from FriendlyNPC. Programmer and FriendlyNPC branched away from each other on the inheritance tree, so inheriting from both of them would have conflicts, because some of the same functions have been implemented in different ways on the two of them. 1) Is there a better way to order these classes to avoid these conflicts? Having three subclasses; Friendly, Enemy and Neutral; from each type of NPC; Engineer, Scientist, and Programmer; would amount to a huge number of classes. I would share specific implementation details, but I am writing the game slowly, piece by piece, and so I haven't implemented past Character yet. 2) Is there a place where I can learn these programming paradigms? I am already trying to take advantage of some good design patterns, like MVC architecture and Mediator objects. The whole point of this project is to write something in good style. It is difficult to tell what should become a subclass and what should become a state (i.e. Friendly boolean v. Friendly class). Having many states slows down code with if statements and makes classes long and unwieldy. On the other hand, having a class for everything isn't practical. 3) Are there good rules of thumb or resources to learn more about this? 4) Finally, where does templating come in to this? How should I coordinate templates into my class structure? I have never actually taken advantage of templating honestly, but I hear that it increases modularity, which means good code.

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  • How to safely copy an object?

    - by Prog
    This question is going to be a little long. Please bear with me. Something that happened in a project of mine made me think about how to safely copy objects. I'll present the situation I had and then ask a question. There was a class SomeClass: class SomeClass{ Thing[] things; public SomeClass(Thing[] things){ this.things = things; } // irrelevant stuff omitted public SomeClass copy(){ return new SomeClass(things); } } There was another class Processor that takes SomeClass objects, copies them (via someClassInstance.copy()), manipulates the copy's state, and returns the copy. Here it is: class Processor{ public SomeClass processObject(SomeClass object){ SomeClass copy = object.copy(); manipulateTheCopy(copy); return copy; } // irrelevant stuff omitted } I ran this, and it had bugs. I looked into these bugs, and it turned out that the manipulations Processor does on copy actually affect not only the copy, but also the original SomeClass object that was passed into processObject. I found out that it was because the original and the copy shared state - because the original passed it's field things into the copy when creating it. This made me realize that copying objects is harder than simply instantiating them with the same fields as the original. For the two objects to be completely disconnected, without any shared state, each of the fields passed to the copy also has to be copied. And if that object contains other objects - they have to be copied too. And so on. So basically, in order to be able to actually copy an object, each class in the system must have a copy() method, that also invokes copy() on all of it's fields, and so on. So for example, for copy() in SomeClass to work, it needs to look like this: public SomeClass copy(){ Thing[] copyThings = new Thing[things.length]; for(int i=0; i<things.length; i++) copyThings[i] = things[i].copy(); return new SomeClass(copyThings); } And if Thing has object fields of it's own, than it's own copy() method must be appropriate: class Thing{ Apple apple; Pencil pencil; int number; public Thing(Apple apple, Pencil pencil, int number){ this.apple = apple; this.pencil = pencil; this.number = number; } public Thing copy(){ // 'number' is a primitve. return new Thing(apple.getCopy(), pencil.getCopy(), number); } } And so on. Of course, instead of all classes having a copy() method, the copying mechanism can happen in all of the getters and the constructors of classes (unless places where it isn't suitable, for example when the field points to an external object, not to an object that 'is part' of this object). Still, that means that in order to be able to safely copy an object - most classes would have to have copying mechanisms in their getters. My question is divided into two parts: How frequently do you need to get a copy of an object? Is this a regular issue? Is the technique described common and/or reasonable? Or is there a better way to make safe copies of objects? Or is there an easier way to safely copy objects, without them sharing any state?

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  • Investigating Strategies For Functional Decomposition

    - by Liam McLennan
    Introducing Functional Decomposition Before I begin I must apologise. I think I am using the term ‘functional decomposition’ loosely, and probably incorrectly. For the purpose of this article I use functional decomposition to mean the recursive splitting of a large problem into increasingly smaller ones, so that the one large problem may be solved by solving a set of smaller problems. The justification for functional decomposition is that the decomposed problem is more easily solved. As software developers we recognise that the smaller pieces are more easily tested, since they do less and are more cohesive. Functional decomposition is important to all scientific pursuits. Once we understand natural selection we can start to look for humanities ancestral species, once we understand the big bang we can trace our expanding universe back to its origin. Isaac Newton acknowledged the compositional nature of his scientific achievements: If I have seen further than others, it is by standing upon the shoulders of giants   The Two Strategies For Functional Decomposition of Computer Programs Private Methods When I was working on my undergraduate degree I was taught to functionally decompose problems by using private methods. Consider the problem of painting a house. The obvious solution is to solve the problem as a single unit: public void PaintAHouse() { // all the things required to paint a house ... } We decompose the problem by breaking it into parts: public void PaintAHouse() { PaintUndercoat(); PaintTopcoat(); } private void PaintUndercoat() { // everything required to paint the undercoat } private void PaintTopcoat() { // everything required to paint the topcoat } The problem can be recursively decomposed until a sufficiently granular level of detail is reached: public void PaintAHouse() { PaintUndercoat(); PaintTopcoat(); } private void PaintUndercoat() { prepareSurface(); fetchUndercoat(); paintUndercoat(); } private void PaintTopcoat() { fetchPaint(); paintTopcoat(); } According to Wikipedia, at least one computer programmer has referred to this process as “the art of subroutining”. The practical issues that I have encountered when using private methods for decomposition are: To preserve the top level API all of the steps must be private. This means that they can’t easily be tested. The private methods often have little cohesion except that they form part of the same solution. Decomposing to Classes The alternative is to decompose large problems into multiple classes, effectively using a class instead of each private method. The API delegates to related classes, so the API is not polluted by the sub-steps of the problem, and the steps can be easily tested because they are each in their own highly cohesive class. Additionally, I think that this technique facilitates better adherence to the Single Responsibility Principle, since each class can be decomposed until it has precisely one responsibility. Revisiting my previous example using class composition: public class HousePainter { private undercoatPainter = new UndercoatPainter(); private topcoatPainter = new TopcoatPainter(); public void PaintAHouse() { undercoatPainter.Paint(); topcoatPainter.Paint(); } } Summary When decomposing a problem there is more than one way to represent the sub-problems. Using private methods keeps the logic in one place and prevents a proliferation of classes (thereby following the four rules of simple design) but the class decomposition is more easily testable and more compatible with the Single Responsibility Principle.

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  • Kinect losing tracked players with Beta2 SDK

    - by Eric B
    So i'm creating a game using the Beta2 SDK for Kinect. The issue i am having is that in the middle of gameplay if another person enters the Kinects FOV it stops tracking the player and will not track anyone else for several minutes. Same deal if the player leaves the FOV and reenters it. Here is what im using to detect players. void nui_SkeletonFrameReady(object sender, SkeletonFrameReadyEventArgs e) { int playersAlive = 0; // reset lists skeletons = new Dictionary<int, SkeletonData>(); //create a new list for skeletons menuSkeleton = new List<SkeletonData>(); initialPlayers = new Dictionary<float, SkeletonData>(); //create a new list for initialPlayers foreach (SkeletonData s in e.SkeletonFrame.Skeletons) //for each skeleton the kinect has detected { if (s.TrackingState == SkeletonTrackingState.Tracked) // players found { menuSkeleton.Add(s); if (initialized) // after initialization { skeletons.Add(s.TrackingID, s); } else // before initialization initialPlayers.Add(s.Joints[JointID.ShoulderCenter].Position.X, s); //if we are not initialized then add this player to the inital player list. playersAlive++; } } if (playersAlive == TOTAL_PLAYERS_ALLOWED) // If there is one player { if (!inMiniGame) // Before the game starts gameStart = DateTime.Now; // Reset initialization timer if (!initialized) // Before initialization // NOTE TO SELF I TOOK OUT && inMenu { InitializePlayers(); if (DateTime.Now.Subtract(gameStart).TotalMilliseconds > INITIALIZATION_WAIT_TIME) { initialized = true; // initialize timers from fixed starting time if (inMiniGame) //if the game has started { gamePause = gameStart; //TODO ERIC: Initialize any Timers Here } } } } } /// <summary> /// this function initializes the players adding them to a list /// and making one of the players the menu controller, for LIM we will need to change the code so that the /// game only recognizes and supports one player at a time /// variable names will need to be change as well. /// </summary> private void InitializePlayers() { List<float> initialPos = new List<float>(); // used to track starting positions players = new Dictionary<int, Player>(); foreach (float pos in initialPlayers.Keys) { initialPos.Add(pos); //add position of each inital player to list } float first = initialPos[0]; // left player first, right second Player player = new Player(initialPlayers[first].TrackingID, true); player.PlayerNumber = PLAYER_ONE; player.Skeleton = initialPlayers[first]; player.Specifics = new PlayerSpecifics(player.PlayerNumber); player.Specifics.PauseTimer = gameStart; players.Add(initialPlayers[first].TrackingID, player); menuController = initialPlayers[first].TrackingID; //menu controller is player 1 } This is a one player game. Also when the game starts Initialize is set to false, and gets set to true when i go from the games menu into the gameplay. So can anyone see any issues with this code block that would cause the kinect to lose players as they enter/exit the FOV? and not re-track them? Thank you for any help.

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  • Patterns for a tree of persistent data with multiple storage options?

    - by Robin Winslow
    I have a real-world problem which I'll try to abstract into an illustrative example. So imagine I have data objects in a tree, where parent objects can access children, and children can access parents: // Interfaces interface IParent<TChild> { List<TChild> Children; } interface IChild<TParent> { TParent Parent; } // Classes class Top : IParent<Middle> {} class Middle : IParent<Bottom>, IChild<Top> {} class Bottom : IChild<Middle> {} // Usage var top = new Top(); var middles = top.Children; // List<Middle> foreach (var middle in middles) { var bottoms = middle.Children; // List<Bottom> foreach (var bottom in bottoms) { var middle = bottom.Parent; // Access the parent var top = middle.Parent; // Access the grandparent } } All three data objects have properties that are persisted in two data stores (e.g. a database and a web service), and they need to reflect and synchronise with the stores. Some objects only request from the web service, some only write to it. Data Mapper My favourite pattern for data access is Data Mapper, because it completely separates the data objects themselves from the communication with the data store: class TopMapper { public Top FetchById(int id) { var top = new Top(DataStore.TopDataById(id)); top.Children = MiddleMapper.FetchForTop(Top); return Top; } } class MiddleMapper { public Middle FetchById(int id) { var middle = new Middle(DataStore.MiddleDataById(id)); middle.Parent = TopMapper.FetchForMiddle(middle); middle.Children = BottomMapper.FetchForMiddle(bottom); return middle; } } This way I can have one mapper per data store, and build the object from the mapper I want, and then save it back using the mapper I want. There is a circular reference here, but I guess that's not a problem because most languages can just store memory references to the objects, so there won't actually be infinite data. The problem with this is that every time I want to construct a new Top, Middle or Bottom, it needs to build the entire object tree within that object's Parent or Children property, with all the data store requests and memory usage that that entails. And in real life my tree is much bigger than the one represented here, so that's a problem. Requests in the object In this the objects request their Parents and Children themselves: class Middle { private List<Bottom> _children = null; // cache public List<Bottom> Children { get { _children = _children ?? BottomMapper.FetchForMiddle(this); return _children; } set { BottomMapper.UpdateForMiddle(this, value); _children = value; } } } I think this is an example of the repository pattern. Is that correct? This solution seems neat - the data only gets requested from the data store when you need it, and thereafter it's stored in the object if you want to request it again, avoiding a further request. However, I have two different data sources. There's a database, but there's also a web service, and I need to be able to create an object from the web service and save it back to the database and then request it again from the database and update the web service. This also makes me uneasy because the data objects themselves are no longer ignorant of the data source. We've introduced a new dependency, not to mention a circular dependency, making it harder to test. And the objects now mask their communication with the database. Other solutions Are there any other solutions which could take care of the multiple stores problem but also mean that I don't need to build / request all the data every time?

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  • Generic Adjacency List Graph implementation

    - by DmainEvent
    I am trying to come up with a decent Adjacency List graph implementation so I can start tooling around with all kinds of graph problems and algorithms like traveling salesman and other problems... But I can't seem to come up with a decent implementation. This is probably because I am trying to dust the cobwebs off my data structures class. But what I have so far... and this is implemented in Java... is basically an edgeNode class that has a generic type and a weight-in the event the graph is indeed weighted. public class edgeNode<E> { private E y; private int weight; //... getters and setters as well as constructors... } I have a graph class that has a list of edges a value for the number of Vertices and and an int value for edges as well as a boolean value for whether or not it is directed. The brings up my first question, if the graph is indeed directed, shouldn't I have a value in my edgeNode class? Or would I just need to add another vertices to my LinkedList? That would imply that a directed graph is 2X as big as an undirected graph wouldn't it? public class graph { private List<edgeNode<?>> edges; private int nVertices; private int nEdges; private boolean directed; //... getters and setters as well as constructors... } Finally does anybody have a standard way of initializing there graph? I was thinking of reading in a pipe-delimited file but that is so 1997. public graph GenereateGraph(boolean directed, String file){ List<edgeNode<?>> edges; graph g; try{ int count = 0; String line; FileReader input = new FileReader("C:\\Users\\derekww\\Documents\\JavaEE Projects\\graphFile"); BufferedReader bufRead = new BufferedReader(input); line = bufRead.readLine(); count++; edges = new ArrayList<edgeNode<?>>(); while(line != null){ line = bufRead.readLine(); Object edgeInfo = line.split("|")[0]; int weight = Integer.parseInt(line.split("|")[1]); edgeNode<String> e = new edgeNode<String>((String) edges.add(e); } return g; } catch(Exception e){ return null; } } I guess when I am adding edges if boolean is true I would be adding a second edge. So far, this all depends on the file I write. So if I wrote a file with the following Vertices and weights... Buffalo | 18 br Pittsburgh | 20 br New York | 15 br D.C | 45 br I would obviously load them into my list of edges, but how can I represent one vertices connected to the other... so on... I would need the opposite vertices? Say I was representing Highways connected to each city weighted and un-directed (each edge is bi-directional with weights in some fictional distance unit)... Would my implementation be the best way to do that? I found this tutorial online Graph Tutorial that has a connector object. This appears to me be a collection of vertices pointing to each other. So you would have A and B each with there weights and so on, and you would add this to a list and this list of connectors to your graph... That strikes me as somewhat cumbersome and a little dismissive of the adjacency list concept? Am I wrong and that is a novel solution? This is all inspired by steve skiena's Algorithm Design Manual. Which I have to say is pretty good so far. Thanks for any help you can provide.

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  • Executing Stored Procedures in Visual Studio LightSwitch.

    - by dataintegration
    A LightSwitch Project is very easy way to visualize and manipulate information directly from one of our ADO.NET Providers. But when it comes to executing the Stored Procedures, it can be a bit more complicated. In this article, we will demonstrate how to execute a Stored Procedure in LightSwitch. For the purposes of this article, we will be using the RSSBus Email Data Provider, but the same process will work with any of our ADO.NET Providers. Creating the RIA Service. Step 1: Open Visual Studio and create a new WCF RIA Service Class Project. Step 2:Add the reference to the RSSBus Email Data Provider dll in the (ProjectName).Web project. Step 3: Add a new Domain Service Class to the (ProjectName).Web project. Step 4: In the new Domain Service Class, create a new class with the attributes needed for the Stored Procedure's parameters. In this demo, the Stored Procedure we are executing is called SendMessage. The parameters we will need are as follows: public class NewMessage{ [Key] public int ID { get; set; } public string FromEmail { get; set; } public string ToEmail { get; set; } public string Subject { get; set; } public string Text { get; set; } } Note: The created class must have an ID which will serve as the key value. Step 5: Create a new method that will executed when the insert event fires. Inside this method you can use the standards ADO.NET code which will execute the stored procedure. [Insert] public void SendMessage(NewMessage newMessage) { try { EmailConnection conn = new EmailConnection(connectionString); EmailCommand comm = new EmailCommand("SendMessage", conn); comm.CommandType = System.Data.CommandType.StoredProcedure; if (!newMessage.FromEmail.Equals("")) comm.Parameters.Add(new EmailParameter("@From", newMessage.FromEmail)); if (!newMessage.ToEmail.Equals("")) comm.Parameters.Add(new EmailParameter("@To", newMessage.ToEmail)); if (!newMessage.Subject.Equals("")) comm.Parameters.Add(new EmailParameter("@Subject", newMessage.Subject)); if (!newMessage.Text.Equals("")) comm.Parameters.Add(new EmailParameter("@Text", newMessage.Text)); comm.ExecuteNonQuery(); } catch (Exception exc) { Console.WriteLine(exc.Message); } } Step 6: Create a query method. We are not going to be using getNewMessages(), so it does not matter what it returns for the purpose of our example, but you will need to create a method for the query event as well. [Query(IsDefault=true)] public IEnumerable<NewMessage> getNewMessages() { return null; } Step 7: Rebuild the whole solution. Creating the LightSwitch Project. Step 8: Open Visual Studio and create a new LightSwitch Application Project. Step 9: On the Data Sources, add a new data source. Choose a WCF RIA Service Step 10: Choose to add a new reference and select the (Project Name).Web.dll generated from the RIA Service. Step 11: Select the entities you would like to import. In this case, we are using the recently created NewMessage entity. Step 13: On the Screens section, create a new screen and select the NewMessage entity as the Screen Data. Step 14: After you run the project, you will be able to add a new record and save it. This will execute the Stored Procedure and send the new message. If you create a screen to check the sent messages, you can refresh this screen to see the mail you sent. Sample Project To help you with get started using stored procedures in LightSwitch, download the fully functional sample project. You will also need the RSSBus Email Data Provider to make the connection. You can download a free trial here.

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  • SQL Server: Writing CASE expressions properly when NULLs are involved

    - by Mladen Prajdic
    We’ve all written a CASE expression (yes, it’s an expression and not a statement) or two every now and then. But did you know there are actually 2 formats you can write the CASE expression in? This actually bit me when I was trying to add some new functionality to an old stored procedure. In some rare cases the stored procedure just didn’t work correctly. After a quick look it turned out to be a CASE expression problem when dealing with NULLS. In the first format we make simple “equals to” comparisons to a value: SELECT CASE <value> WHEN <equals this value> THEN <return this> WHEN <equals this value> THEN <return this> -- ... more WHEN's here ELSE <return this> END Second format is much more flexible since it allows for complex conditions. USE THIS ONE! SELECT CASE WHEN <value> <compared to> <value> THEN <return this> WHEN <value> <compared to> <value> THEN <return this> -- ... more WHEN's here ELSE <return this> END Now that we know both formats and you know which to use (the second one if that hasn’t been clear enough) here’s an example how the first format WILL make your evaluation logic WRONG. Run the following code for different values of @i. Just comment out any 2 out of 3 “SELECT @i =” statements. DECLARE @i INTSELECT  @i = -1 -- first resultSELECT  @i = 55 -- second resultSELECT  @i = NULL -- third resultSELECT @i AS OriginalValue, -- first CASE format. DON'T USE THIS! CASE @i WHEN -1 THEN '-1' WHEN NULL THEN 'We have a NULL!' ELSE 'We landed in ELSE' END AS DontUseThisCaseFormatValue, -- second CASE format. USE THIS! CASE WHEN @i = -1 THEN '-1' WHEN @i IS NULL THEN 'We have a NULL!' ELSE 'We landed in ELSE' END AS UseThisCaseFormatValue When the value of @i is –1 everything works as expected, since both formats go into the –1 WHEN branch. When the value of @i is 55 everything again works as expected, since both formats go into the ELSE branch. When the value of @i is NULL the problems become evident. The first format doesn’t go into the WHEN NULL branch because it makes an equality comparison between two NULLs. Because a NULL is an unknown value: NULL = NULL is false. That is why the first format goes into the ELSE Branch but the second format correctly handles the proper IS NULL comparison.   Please use the second more explicit format. Your future self will be very grateful to you when he doesn’t have to discover these kinds of bugs.

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  • Why is x=x++ undefined?

    - by ugoren
    It's undefined because the it modifies x twice between sequence points. The standard says it's undefined, therefore it's undefined. That much I know. But why? My understanding is that forbidding this allows compilers to optimize better. This could have made sense when C was invented, but now seems like a weak argument. If we were to reinvent C today, would we do it this way, or can it be done better? Or maybe there's a deeper problem, that makes it hard to define consistent rules for such expressions, so it's best to forbid them? So suppose we were to reinvent C today. I'd like to suggest simple rules for expressions such as x=x++, which seem to me to work better than the existing rules. I'd like to get your opinion on the suggested rules compared to the existing ones, or other suggestions. Suggested Rules: Between sequence points, order of evaluation is unspecified. Side effects take place immediately. There's no undefined behavior involved. Expressions evaluate to this value or that, but surely won't format your hard disk (strangely, I've never seen an implementation where x=x++ formats the hard disk). Example Expressions x=x++ - Well defined, doesn't change x. First, x is incremented (immediately when x++ is evaluated), then it's old value is stored in x. x++ + ++x - Increments x twice, evaluates to 2*x+2. Though either side may be evaluated first, the result is either x + (x+2) (left side first) or (x+1) + (x+1) (right side first). x = x + (x=3) - Unspecified, x set to either x+3 or 6. If the right side is evaluated first, it's x+3. It's also possible that x=3 is evaluated first, so it's 3+3. In either case, the x=3 assignment happens immediately when x=3 is evaluated, so the value stored is overwritten by the other assignment. x+=(x=3) - Well defined, sets x to 6. You could argue that this is just shorthand for the expression above. But I'd say that += must be executed after x=3, and not in two parts (read x, evaluate x=3, add and store new value). What's the Advantage? Some comments raised this good point. It's not that I'm after the pleasure of using x=x++ in my code. It's a strange and misleading expression. What I want is to be able to understand complicated expressions. Normally, a complicated expression is no more than the sum of its parts. If you understand the parts and the operators combining them, you can understand the whole. C's current behavior seems to deviate from this principle. One assignment plus another assignment suddenly doesn't make two assignments. Today, when I look at x=x++, I can't say what it does. With my suggested rules, I can, by simply examining its components and their relations.

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