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  • Ladder-like word game in Java

    - by sasquatch90
    I've found this question http://stackoverflow.com/questions/2844190/choosing-design-method-for-ladder-like-word-game and I would also like to do this kind of program. I've written some code but already have two issues. Here's what I already have : GRID : public class Grid { public Grid(){} public Grid( Element e ){} } ELEMENT : public class Element { final int INVISIBLE = 0; final int EMPTY = 1; final int FIRST_LETTER = 2; final int OTHER_LETTER = 3; private int state; private String letter; public Element(){} //empty block public Element(int state){ this("", 0); } //filled block public Element(String s, int state){ this.state = state; this.letter = s; } public static void changeState(int s){ } public int getState(){ return state; } public boolean equalLength(){ return true; } public boolean equalValue(){ return true; } @Override public String toString(){ return "["+letter+"]"; } } MAIN: import java.util.Scanner; public class Main { public static void main(String[] args){ Scanner sc = new Scanner(System.in); System.out.println("Height: "); while (!sc.hasNextInt()) { System.out.println("int, please!"); sc.next(); } final int height = sc.nextInt(); Grid[] game = new Grid[height]; for(int i = 1; i <= height; i++) { String s; do { System.out.println("Length " + i + ", please!"); s = sc.next(); } while (s.length() != i); Element[] line = new Element[s.length()+1]; Element single = null; String[] temp = null; //issue here temp = s.split(""); System.out.println("s.length: "+s.length()); System.out.println("temp.length: "+temp.length); // for(String str : temp){ System.out.println("str:"+str); } for (int k = 0 ; k < temp.length ; k++) { if( k == 0 ){ single = new Element(temp[k], 2); System.out.println("single1: "+single); } else{ single = new Element(temp[k], 3); System.out.println("single2: "+single); } line[k] = single; } for (Element l : line) { System.out.println("line:"+l); } //issue here game[i] = line; } // for (Grid g : game) { System.out.println(g); } } } And sample output for debug : Height: 3 Length 1, please! A s.length: 1 temp.length: 2 str: str:A single1: [] single2: [A] line:[] line:[A] Here's what I think it should work like. I grab a word from user. Next create Grid element for whole game. Then for each line I create Element[] array called line. I split the given text and here's the first problem. Why string.split() adds a whitespace ? You can see clearly in output that it is added for no reason. How can I get rid of it (now I had to add +1 to the length of line just to run the code). Continuing I'm throwing the splitted text into temporary String array and next from each letter I create Element object and throw it to line array. Apart of this empty space output looks fine. But next problem is with Grid. I've created constructor taking Element as an argument, but still I can't throw line as Grid[] elements because of 'incompatible types'. How can I fix that ? Am I even doing it right ? Maybe I should get rid of line as Element[] and just create Grid[][] ?

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  • how to: handle exceptions, best practices

    - by b0x0rz
    need to implement a global error handling, so maybe you can help out with the following example... i have this code: public bool IsUserAuthorizedToSignIn(string userEMailAddress, string userPassword) { // get MD5 hash for use in the LINQ query string passwordSaltedHash = this.PasswordSaltedHash(userEMailAddress, userPassword); // check for email / password / validity using (UserManagementDataContext context = new UserManagementDataContext()) { var users = from u in context.Users where u.UserEMailAdresses.Any(e => e.EMailAddress == userEMailAddress) && u.UserPasswords.Any(p => p.PasswordSaltedHash == passwordSaltedHash) && u.IsActive == true select u; // true if user found return (users.Count() == 1) ? true : false; } } and the md5 as well: private string PasswordSaltedHash(string userEMailAddress, string userPassword) { MD5 hasher = MD5.Create(); byte[] data = hasher.ComputeHash(Encoding.Default.GetBytes(userPassword + userEMailAddress)); StringBuilder stringBuilder = new StringBuilder(); for (int i = 0; i < data.Length; i++) { stringBuilder.Append(data[i].ToString("x2")); } Trace.WriteLine(String.Empty); Trace.WriteLine("hash: " + stringBuilder.ToString()); return stringBuilder.ToString(); } so, how would i go about handling exceptions from these functions? they first one is called from the Default.aspx page. the second one is only called from other functions from the class library. what is the best practice? surround code INSIDE each function with try-catch surround the FUNCTION CALL with try-catch something else?? what to do if exceptions happen? in this example: this is a user sign in, so somehow even if everything fails, the user should get some meaningful info - along the lines: sign in ok (just redirect), sign in not ok (wrong user name / password), sign in not possible due to internal problems, sorry (exception happened). for the first function i am worried if there is a problem with database access. not sure if there is anything that needs to be handled in the second one. thnx for the info. how would you do it? need specific info on this (easier for me to understand), but also general info on how to handle other tasks/functions. i looked around the internet but everyone has different things to say, so unsure what to do... will go with either most votes here, or most logicaly explained answer :) thank you.

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  • Checking if an int is prime more efficiently

    - by SipSop
    I recently was part of a small java programming competition at my school. My partner and I have just finished our first pure oop class and most of the questions were out of our league so we settled on this one (and I am paraphrasing somewhat): "given an input integer n return the next int that is prime and its reverse is also prime for example if n = 18 your program should print 31" because 31 and 13 are both prime. Your .class file would then have a test case of all the possible numbers from 1-2,000,000,000 passed to it and it had to return the correct answer within 10 seconds to be considered valid. We found a solution but with larger test cases it would take longer than 10 seconds. I am fairly certain there is a way to move the range of looping from n,..2,000,000,000 down as the likely hood of needing to loop that far when n is a low number is small, but either way we broke the loop when a number is prime under both conditions is found. At first we were looping from 2,..n no matter how large it was then i remembered the rule about only looping to the square root of n. Any suggestions on how to make my program more efficient? I have had no classes dealing with complexity analysis of algorithms. Here is our attempt. public class P3 { public static void main(String[] args){ long loop = 2000000000; long n = Integer.parseInt(args[0]); for(long i = n; i<loop; i++) { String s = i +""; String r = ""; for(int j = s.length()-1; j>=0; j--) r = r + s.charAt(j); if(prime(i) && prime(Long.parseLong(r))) { System.out.println(i); break; } } System.out.println("#"); } public static boolean prime(long p){ for(int i = 2; i<(int)Math.sqrt(p); i++) { if(p%i==0) return false; } return true; } } ps sorry if i did the formatting for code wrong this is my first time posting here. Also the output had to have a '#' after each line thats what the line after the loop is about Thanks for any help you guys offer!!!

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  • open,edit and save xml file with schema using php

    - by Neat
    Hy... I'm new in XML Schema, XSL,... (I have basic understanding) On web page: http://w3schools.com/xsl/xsl_editxml.asp is shown example for open,edit,save xml file, but with asp. Do anyone know how can i open/edit and save xml file using php for next example: <?xml version="1.0" encoding="ISO-8859-1"?> <tools> <tool id="1"> <field id="prodName"> <value>HAMMER HG2606</value> </field> <field id="prodNo"> <value>32456240</value> </field> <field id="price"> <value>$30.00</value> </field> </tool> <tool id="2"> <field id="prodName"> <value>Audi</value> </field> <field id="prodNo"> <value>88885</value> </field> <field id="price"> <value>$26.00</value> </field> </tool> </tools> and do i need <tool id="2"> or just <tool> is enough. Thanks very much on replay, and i don't need another xsl like shown on w3s, just fine is refresh submitted php file after submit (will do something with ajax after). I saw replay from Mr. Writman on questions/377632/add-update-and-edit-an-xml-file-with-php but that is for now 2 complex for me...:) is there any simpler answer (solution). Thanks in advance!!!

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  • How to measure a canvas that has auto height and with

    - by Wymmeroo
    Hi Folks, I'm a beginner in silverlight so i hope i can get an answer that brings me some more light in the measure process of silverlight. I found an interessting flap out control from silverlight slide control and now I try to use it in my project. So that the slide out is working proper, I have to place the user control on a canvas. The user control then uses for itself the height of its content. I just wanna change that behavior so that the height is set to the available space from the parent canvas. You see the uxBorder where the height is set. How can I measure the actual height and set it to the border? I tried it with Height={Binding ElementName=notificationCanvas, Path=ActualHeight} but this dependency property has no callback, so the actualHeight is never set. What I want to achieve is a usercontrol like the tweetboard per example on Jesse Liberty's blog Sorry for my English writing, I hope you understand my question. <Canvas x:Name="notificationCanvas" Background="Red"> <SlideEffectEx:SimpleSlideControl GripWidth="20" GripTitle="Task" GripHeight="100"> <Border x:Name="uxBorder" BorderThickness="2" CornerRadius="5" BorderBrush="DarkGray" Background="DarkGray" Padding="5" Width="300" Height="700" > <StackPanel> <TextBlock Text="Tasks"></TextBlock> <Button x:Name="btn1" Margin="5" Content="{Binding ElementName=MainBorder, Path=Height}"></Button> <Button x:Name="btn2" Margin="5" Content="Second Button"></Button> <Button x:Name="btn3" Margin="5" Content="Third Button"></Button> <Button x:Name="btn1_Copy" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy1" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy2" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy3" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy4" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy5" Margin="5" Content="First Button"/> <Button x:Name="btn1_Copy6" Margin="5" Content="First Button"/> </StackPanel> </Border> </SlideEffectEx:SimpleSlideControl>

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  • Is there any alternative to obfuscation to make it harder to get any string in javascript?

    - by MarceloRamires
    I use DropBox and I've had some trouble reaching to my files from other computers: I not always want to login to anything when I'm in a public computer, but I like being able to reach my stuff from wherever I am. So I've made a simple little application that when put in the public folder, ran and given the right UID, creates (still in your public folder) an HTML of all the content in the folder (including subfolders) as a tree of links. But I didn't risk loading it anywhere, since there are slightly private things in there (yes, I know that the folder's name is "PUBLIC"). So I've came up with the idea to make it a simple login page, given the right password, the rest of the page should load. brilliant!, but how? If I did this by redirecting to other HTML on the same folder, I'd still put the html link in the web history and the "url's accessed" history of the administrator. So I should generate itin the same page. I've done it. And currently the page is a textbox and a button, and only if you type in the right password (asked by the generator) the rest of the page loads. The fault is that everything (password, URL's) is easily reachable through the sourcecode. Now, assuming I only want to avoid silly people to get it all too easily, not make a bulletproof all-content-holding NSA certified website, I though about some ways to make these informations a bit harder to get. As you may have already figured, I use a streamwritter to write a .HTM file (head, loop through links, bottom), then it's extremely configurable, and I can come up with a pretty messy-but-working c# code, though my javascript knowledge is not that good. Public links in DropBox look like this: http://dl.dropbox.com/u/3045472/img.png Summarizing: How do I hide stuff (MAINLY the password, of course) in my source-code so that no bumb-a-joe that can read, use a computer and press CTRL+U can reach to my stuff too easily ? PS.: It's not that personal, if someone REALLY wants it, it could never be 100% protected, and if it was that important, I wouldnt put it in the public folder, also, if the dude really wants to get it that hard, he should deserve it. PS2.: "Use the ultra-3000'tron obfuscator!!11" is not a real answer, since my javascript is GENERATED by my c# program. PS3.: I don't want other solutions as "use a serverside application and host it somewhere to redirect and bla bla" or "compress the links in a .RAR file and put a password in it" since I'm doing this ALSO to learn, and I want the thrill of it =)

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  • Code-Golf: Friendly Number Abbreviator

    - by David Murdoch
    Based on this question: Is there a way to round numbers into a friendly format? THE CHALLENGE - UPDATED! (removed hundreds abbreviation from spec) The shortest code by character count that will abbreviate an integer (no decimals). Code should include the full program. Relevant range is from 0 - 9,223,372,036,854,775,807 (the upper limit for signed 64 bit integer). The number of decimal places for abbreviation will be positive. You will not need to calculate the following: 920535 abbreviated -1 place (which would be something like 0.920535M). Numbers in the tens and hundreds place (0-999) should never be abbreviated (the abbreviation for the number 57 to 1+ decimal places is 5.7dk - it is unneccessary and not friendly). Remember to round half away from zero (23.5 gets rounded to 24). Banker's rounding is verboten. Here are the relevant number abbreviations: h = hundred (102) k = thousand (103) M = million (106) G = billion (109) T = trillion (1012) P = quadrillion (1015) E = quintillion (1018) SAMPLE INPUTS/OUTPUTS (inputs can be passed as separate arguments): First argument will be the integer to abbreviate. The second is the number of decimal places. 12 1 => 12 // tens and hundreds places are never rounded 1500 2 => 1.5k 1500 0 => 2k // look, ma! I round UP at .5 0 2 => 0 1234 0 => 1k 34567 2 => 34.57k 918395 1 => 918.4k 2134124 2 => 2.13M 47475782130 2 => 47.48G 9223372036854775807 3 => 9.223E // ect... . . . Original answer from related question (javascript, does not follow spec): function abbrNum(number, decPlaces) { // 2 decimal places => 100, 3 => 1000, etc decPlaces = Math.pow(10,decPlaces); // Enumerate number abbreviations var abbrev = [ "k", "m", "b", "t" ]; // Go through the array backwards, so we do the largest first for (var i=abbrev.length-1; i>=0; i--) { // Convert array index to "1000", "1000000", etc var size = Math.pow(10,(i+1)*3); // If the number is bigger or equal do the abbreviation if(size <= number) { // Here, we multiply by decPlaces, round, and then divide by decPlaces. // This gives us nice rounding to a particular decimal place. number = Math.round(number*decPlaces/size)/decPlaces; // Add the letter for the abbreviation number += abbrev[i]; // We are done... stop break; } } return number; }

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  • How to avoid repetition when working with primitive types?

    - by I82Much
    I have the need to perform algorithms on various primitive types; the algorithm is essentially the same with the exception of which type the variables are. So for instance, /** * Determine if <code>value</code> is the bitwise OR of elements of <code>validValues</code> array. * For instance, our valid choices are 0001, 0010, and 1000. * We are given a value of 1001. This is valid because it can be made from * ORing together 0001 and 1000. * On the other hand, if we are given a value of 1111, this is invalid because * you cannot turn on the second bit from left by ORing together those 3 * valid values. */ public static boolean isValid(long value, long[] validValues) { for (long validOption : validValues) { value &= ~validOption; } return value != 0; } public static boolean isValid(int value, int[] validValues) { for (int validOption : validValues) { value &= ~validOption; } return value != 0; } How can I avoid this repetition? I know there's no way to genericize primitive arrays, so my hands seem tied. I have instances of primitive arrays and not boxed arrays of say Number objects, so I do not want to go that route either. I know there are a lot of questions about primitives with respect to arrays, autoboxing, etc., but I haven't seen it formulated in quite this way, and I haven't seen a decisive answer on how to interact with these arrays. I suppose I could do something like: public static<E extends Number> boolean isValid(E value, List<E> numbers) { long theValue = value.longValue(); for (Number validOption : numbers) { theValue &= ~validOption.longValue(); } return theValue != 0; } and then public static boolean isValid(long value, long[] validValues) { return isValid(value, Arrays.asList(ArrayUtils.toObject(validValues))); } public static boolean isValid(int value, int[] validValues) { return isValid(value, Arrays.asList(ArrayUtils.toObject(validValues))); } Is that really much better though? Any thoughts in this matter would be appreciated.

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  • My style/control template out my calendar's blackout dates.

    - by Chris
    Howdy, My C#/WPF project needs a calendar. We're going to be using it to pick a range of dates for appointment scheduling. I'm told the default calendar is too small to be used by some of our reps so I've been working on resizing it. <toolkit:Calendar Grid.Row="1" x:Name="DateWindowCalendar" BorderBrush="White" BorderThickness="0" Style="{StaticResource PopupCalendarStyle}" DisplayMode="Month" SelectionMode="SingleRange" DisplayDateStart="{Binding FirstDayOfMonth}" AutomationProperties.AutomationId="ToolkitCalendarId" VerticalAlignment="Top"> </toolkit:Calendar> And I've created this styling: <Style x:Key="PopupCalendarStyle" TargetType="toolkit:Calendar"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="toolkit:Calendar"> <StackPanel Margin="0" HorizontalAlignment="Center" x:Name="Root"> <toolkit:Calendar x:Name="Calendar" SelectedDate="{TemplateBinding SelectedDate}" DisplayDateStart="{TemplateBinding DisplayDateStart}" SelectionMode="{TemplateBinding SelectionMode}" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" SelectedDatesChanged="Calendar_SelectedDatesChanged"> <toolkit:Calendar.CalendarDayButtonStyle> <Style> <Setter Property="Button.Height" Value="34"/> <Setter Property="Button.Width" Value="34" /> <Setter Property="Button.FontSize" Value="16" /> </Style> </toolkit:Calendar.CalendarDayButtonStyle> <toolkit:Calendar.CalendarButtonStyle> <Style> <Setter Property="Button.Height" Value="34"/> <Setter Property="Button.Width" Value="34"/> <Setter Property="Button.FontSize" Value="16"/> </Style> </toolkit:Calendar.CalendarButtonStyle> </toolkit:Calendar> </StackPanel> </ControlTemplate> </Setter.Value> </Setter> </Style> Everything is almost perfect. I specify my range, I can track the selected dates (granted using the SelectedDatesChanged event instead of the SelectedDates property. The problem is I also need to be able to set blackout dates (usually the period between first of the month and today although sometimes first of the month to a few days from now). Without the styling, this works: DateWindowCalendar.BlackoutDates.Add(new CalendarDateRange( new DateTime(DateTime.Now.Year, DateTime.Now.Month, 01), DateTime.Now)); But when I add the style, I don't get the black out displays being displayed and worse its possible to select the blackout dates. I'm not sure what I missed but I'm hoping someone has an easy answer so that I don't have to rebuild the entire widget. Any help is appreciated. Thanks, Chris

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  • Spring.NET & Immediacy CMS (or how to inject to server side controls without using PageHandlerFactor

    - by Simon Rice
    Is there any way to inject dependencies into an Immediacy CMS control using Spring.NET, ideally without having to use to ContextRegistry when initialising the control? Update, with my own answer The issue here is that Immediacy already has a handler defined in web.config that deals with all aspx pages, & so it's not possible add an entry for Spring.NET's PageHandlerFactory in web.config as per a normal webforms app. That rules out making the control implement ISupportsWebDependencyInjection. Furthermore, most of Immediacy's generated pages are aspx pages that don't physically exist on the drive. I have changed the title of the question to reflect this. What I have done to get Dependency Injection working is: Add the usual entries to web.config for Spring.NET as outlined in the documentation, except for the adding the entry to the <httpHandlers> section. In this case I've got my object definitions in Spring.config. Create the following abstract base class that will deal with all of the Dependency Injection work: DIControl.cs public abstract class DIControl : ImmediacyControl { protected virtual string DIName { get { return this.GetType().Name; } } protected override void OnInit(EventArgs e) { if (ContextRegistry.GetContext().GetObject(DIName, this.GetType()) != null) ContextRegistry.GetContext().ConfigureObject(this, DIName); base.OnInit(e); } } For non-immediacy controls, you can make this server side control inherit from Control or whatever subclass of that you like. For any control with which you wish to use with Spring.NET's Inversion of Control container, define it to inherit from DIControl & add the relelvant entry to Spring.config, for example: SampleControl.cs public class SampleControl : DIControl, INamingContainer { public string Text { get; set; } protected string InjectedText { get; set; } public SampleControl() : base() { Text = "Hello world"; } protected override void RenderContents(HtmlTextWriter output) { output.Write(string.Format("{0} {1}", Text, InjectedText)); } } Spring.config <objects xmlns="http://www.springframework.net"> <object id="SampleControl" type="MyProject.SampleControl, MyAssembly"> <property name="InjectedText" value="from Spring.NET" /> </object> </objects> You can optionally override DIName if you wish to name your entry in Spring.config differently from the name of your class. Provided everything's done correctly, you will have the control writing out "Hello world from Spring.NET!" when used in a page. This solution uses Spring.NET's ContextRegistry from within the control, but I would be surprised if there's no way around that for Immediacy at least since the page objects themselves aren't accessible. However, can this be improved at all from a Spring.NET perspective? Is there maybe an Immediacy plugin that already does this that I'm completely unaware of? Or is there an approach that does this in a more elegant way? I'm open to suggestions.

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  • Facelet selectOneMenu with POJOs and converter problem

    - by c0d3x
    Hi, I want to have a facelet page with a formular and a dropdown menu. With the dropdown menu the user shoul select a POJO of the type Lieferant: public class Lieferant extends AbstractPersistentWarenwirtschaftsObject { private String firma; public Lieferant(WarenwirtschaftDatabaseLayer database, String firma) { this(database, null, firma); } public Lieferant(WarenwirtschaftDatabaseLayer database, Long primaryKey, String firma) { super(database, primaryKey); this.firma = firma; } public String getFirma() { return firma; } @Override public String toString() { return getFirma(); } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((firma == null) ? 0 : firma.hashCode()); return result; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; Lieferant other = (Lieferant) obj; if (firma == null) { if (other.firma != null) return false; } else if (!firma.equals(other.firma)) return false; return true; } } Here is the facelet code that I wrote: <h:selectOneMenu> tag. This tag should display a list of POJOs (not beans) of the type Lieferant. Here is the facelet code: <h:selectOneMenu id="lieferant" value="#{lieferantenBestellungBackingBean.lieferant}"> <f:selectItems var="lieferant" value="#{lieferantenBackingBean.lieferanten}" itemLabel="#{lieferant.firma}" itemValue="#{lieferant.primaryKey}" /> <f:converter converterId="LieferantConverter" /> </h:selectOneMenu> Here is the refenrenced managed backing bean @ManagedBean @RequestScoped public class LieferantenBackingBean extends AbstractWarenwirtschaftsBackingBean { private List<Lieferant> lieferanten; public List<Lieferant> getLieferanten() { if (lieferanten == null) { lieferanten = getApplication().getLieferanten(); } return lieferanten; } } As far as I know, I need a custom converter, to swap beetween POJO and String representations of the Lieferant objects. Here is what the converter looks like: @FacesConverter(value="LieferantConverter") public class LieferantConverter implements Converter { @Override public Object getAsObject(FacesContext context, UIComponent component, String value) { long primaryKey = Long.parseLong(value); WarenwirtschaftApplicationLayer application = WarenwirtschaftApplication.getInstance(); Lieferant lieferant = application.getLieferant(primaryKey); return lieferant; } @Override public String getAsString(FacesContext context, UIComponent component, Object value) { return value.toString(); } } The page loads without any error. When I fill out the formular and submit it, there is an error message displayed on the page: Bestellung:lieferantenBestellungForm:lieferant: Validierungsfehler: Wert ist keine gültige Auswahl translated: validation error: value is not a valid selection Unfortunaltely it does not say which value it is talking about. The converter seems to work correctly. I found this similar question from stackoverflow and this article about selectOneMenu and converters, but I was not able to find the problem in my code. Why is List<SelectItem> used in the example from the second link. Gives the same error for me. Any help would be appreciated. Thanks in advance.

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  • ERROR: Failed to build gem native extension (mysql2 on rails 3.2.3)

    - by Ryan Arneson
    I'm trying to install the mysql2 gem with Rails 3.2.3 and it's failing: ? bundle install Fetching gem metadata from https://rubygems.org/......... Using rake (0.9.2.2) Using i18n (0.6.0) Using multi_json (1.2.0) Using activesupport (3.2.3) Using builder (3.0.0) Using activemodel (3.2.3) Using erubis (2.7.0) Using journey (1.0.3) Using rack (1.4.1) Using rack-cache (1.2) Using rack-test (0.6.1) Using hike (1.2.1) Using tilt (1.3.3) Using sprockets (2.1.2) Using actionpack (3.2.3) Using mime-types (1.18) Using polyglot (0.3.3) Using treetop (1.4.10) Using mail (2.4.4) Using actionmailer (3.2.3) Using arel (3.0.2) Using tzinfo (0.3.32) Using activerecord (3.2.3) Using activeresource (3.2.3) Using bundler (1.1.3) Using coffee-script-source (1.2.0) Using execjs (1.3.0) Using coffee-script (2.2.0) Using rack-ssl (1.3.2) Using json (1.6.6) Using rdoc (3.12) Using thor (0.14.6) Using railties (3.2.3) Using coffee-rails (3.2.2) Using jquery-rails (2.0.2) Installing mysql2 (0.3.11) with native extensions Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension. /Users/rarneson/.rvm/rubies/ruby-1.9.3-p125/bin/ruby extconf.rb checking for rb_thread_blocking_region()... yes checking for rb_wait_for_single_fd()... yes checking for mysql_query() in -lmysqlclient... no checking for main() in -lm... yes checking for mysql_query() in -lmysqlclient... no checking for main() in -lz... yes checking for mysql_query() in -lmysqlclient... no checking for main() in -lsocket... no checking for mysql_query() in -lmysqlclient... no checking for main() in -lnsl... no checking for mysql_query() in -lmysqlclient... no checking for main() in -lmygcc... no checking for mysql_query() in -lmysqlclient... no *** extconf.rb failed *** Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers. Check the mkmf.log file for more details. You may need configuration options. Provided configuration options: --with-opt-dir --with-opt-include --without-opt-include=${opt-dir}/include --with-opt-lib --without-opt-lib=${opt-dir}/lib --with-make-prog --without-make-prog --srcdir=. --curdir --ruby=/Users/rarneson/.rvm/rubies/ruby-1.9.3-p125/bin/ruby --with-mysql-config --without-mysql-config --with-mysql-dir --without-mysql-dir --with-mysql-include --without-mysql-include=${mysql-dir}/include --with-mysql-lib --without-mysql-lib=${mysql-dir}/lib --with-mysqlclientlib --without-mysqlclientlib --with-mlib --without-mlib --with-mysqlclientlib --without-mysqlclientlib --with-zlib --without-zlib --with-mysqlclientlib --without-mysqlclientlib --with-socketlib --without-socketlib --with-mysqlclientlib --without-mysqlclientlib --with-nsllib --without-nsllib --with-mysqlclientlib --without-mysqlclientlib --with-mygcclib --without-mygcclib --with-mysqlclientlib --without-mysqlclientlib Gem files will remain installed in /Users/rarneson/.rvm/gems/ruby-1.9.3-p125/gems/mysql2-0.3.11 for inspection. Results logged to /Users/rarneson/.rvm/gems/ruby-1.9.3-p125/gems/mysql2-0.3.11/ext/mysql2/gem_make.out An error occured while installing mysql2 (0.3.11), and Bundler cannot continue. Make sure that `gem install mysql2 -v '0.3.11'` succeeds before bundling. I'm running bundle install and this is in my Gemfile: gem 'mysql2', '~> 0.3.11' I've currently got MySQL running through MAMP. I'm not sure if this is a bad idea and I should run a vanilla MySQl but it seems my current problem is just getting the gem installed. I've seen quite a few of these problems here on stackoverflow but all seem a bit different or have really complicated solutions. Is there something I'm missing? Something simple? Something stupid? I can provide additional info from the out file if necessary. I've read that some people use SQLite for dev and test then MySQL in prod but that sounds like a pretty horrible idea.

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  • Need help iteratating over an array, retrieve two possibilites, no repeats, for Poker AI

    - by elguapo-85
    Can't really think of a good way to word this question, nor a good title, and maybe the answer is so ridiculously simple that I am missing it. I am working on a poker AI, and I want to calculate the number of hands that exist which are better then mine, I understand how to that, but want I can't figure out is the best way to iterate over a group of cards. So I am at the flop, I know what my two cards are and there are 3 cards on the board. So there are 47 unknown cards and I want to iterate over all possible combination of those 47 cards assuming that two are passed out, so you can't have two cards of the same rank and suit, and you if you have previously calculated a set you don't want to do it over again, because I will being wasting time, and this will be called many times. If you don't understand want I am asking please tell me and I will clarify more. So I can set something up like this, if that element equals one, it means it is not in my hand and not on the board, 4 for each suit, and 13 for each rank. setOfCards[4][13] If I do a simple set of for loops like this: (pseudocode) //remove cards I know are in play from setOfCards by setting values to zero for(int i = 0; i < 4; i++) for(int j = 0; j < 13; j++) for(int k = 0; k < 4; k++) for(int l = 0; l < 4; l++) //skip if values equal zero card1 = setOfCards[i][j] card2 = setOfCards[k][l] //now compare card1, card2 and set of board cards So this is actually going to repeat many values, for example: card1 = AceOfHearts, card2 = KingOfHearts is the same as card1 = KingOfHearts, card2 = AceOfHearts. It will also alter my calculations. How should I go about avoiding this? Also is there a name for this technique? Thank you.

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  • UITableView: Handle cell selection in a mixed cell table view static and dynamic cells

    - by AlexR
    I am trying to mix dynamic and static cells in a grouped table view: I would like to get two sections with static cells at the top followed by a section of dynamic cells (please refer to the screenshot below). I have set the table view contents to static cells. Edit Based on AppleFreak's advice I have changed my code as follows: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell; if (indexPath.section <= 1) { // section <= 1 indicates static cells cell = [super tableView:tableView cellForRowAtIndexPath:indexPath]; } else { // section > 1 indicates dynamic cells CellIdentifier = [NSString stringWithFormat:@"section%idynamic",indexPath.section]; cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath]; } return cell; } However, my app crashes with error message Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath:' for section 0 and row 0. The cell returned from cell = [super tableView:tableView cellForRowAtIndexPath:indexPath] for section 0 and row 0 is nil. What is wrong with my code? Could there be any problems with my outlets? I haven't set any outlets because I am subclassing UITableViewController and supposedly do not any outlets for tableview to be set (?). Any suggestions on how to better do it? Edit II I have recreated my scene in storyboard (please refer to my updated screen shot above) and rewritten the view controller in order to start from a new base. I have also read the description in Apple's forum as applefreak suggested. However, I run in my first problem with the method numberOfSectionsInTableView:tableView, in which I increment the number of static sections (two) by one. - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return [super numberOfSectionsInTableView:tableView] + 1 ; } The app crashed with the error message: Terminating app due to uncaught exception 'NSRangeException', reason: '* -[__NSArrayI objectAtIndex:]: index 2 beyond bounds [0 .. 1]' Why is this code not working for me even though I followed Apple's and applefreak recommendations? It is possible that the tableView has changed a bit in iOS 6? Solution: I got this to work now using AppleFreaks code sample in his answer below. Thank you, AppleFreak! Edit III: Cell Selection: How can I handle cell selection in a mixed (dynamic and static cells) cell table view? When do I call super and when do I call self tableView? When I use [[super tableView] selectRowAtIndexPath:indexPath animated:NO scrollPosition:UITableViewScrollPositionNone] and try to check for the selected index paths with: UITableView *tableView = [super tableView]; if ( [[tableView indexPathForSelectedRow] isEqual:customGrowthIndexPath] ) { .. } I get an return value of nil. As I can't find the source of my error, I really would appreciate your help

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  • feeling insufficient while looking for a programming job ...

    - by user325661
    Hello everybody It's really dream to be programmer for me.So i always wanted to be .I had so small knowledges from commodore basic which i couldn't figure out anything in it .Then i tried to learn Visual basic 6 by myself and result wasn't good as i expected because i even didn't understand classes.Then i left to learning programming and to dream to be programmer. But challenge hadn't finished yet . After all of these i started to learn c# and i did chess engine which i hadn't believe that i can create one.I sometimes feel that i understand many thing about programming like knowing classes ,inheritance,abstract class and methods why exist , interfaces ,extension methods ,static classes ,threads. but i am not expert all in it . i just know that as i need . i don't know still i will learn many thing about these.i have also learned html, css2 , php and database concepts a little sql ,tables relations between primary keys etc but i haven't used them in praticaly . i just did some samples so i feel i am lack of knowledges. As a result still i can't evaluate my skills and can't decide what is my level.I just feel myself one step ahead of junior sometimes :) . Still can't decide that it is time to job seeking. While searching job on web i have never seen a junior advertisement. All looking for a good experiencing one.Nobody care about juniors. When found job advertisement which i feel sufficient myself a little then i start to feel that i think i can't do what they want from me and loosing job after have it in short time would leave many crap feelings into my low self-confidence. Please advise me something ... Also i want to ask some of concentrate questions. 1) If i enter a job which i can't provide their expectations should be in employers responsibility to test me while apply the job ? 2) If i answer "yes , i can " questions which is abstract(for example: can u do something like this) would be my responsibility ? Because such abstract questions is not clear and can't know before start it what i really can or not . 3) i have no professional experiences in this job so i even don't know how teams working on projects but a friend of me said that programmers only write method bodies while seniors create all project.So it looks what i can do really easy but i feel that small companies doesn't work like this so it is better work in a big company for starting who has seniors? 4)last applied job was looking for c# . net developer but then i learn that they need .net web developer.Does it take long time to learn specific sides of web programming while knowing c# desktop programming ? Thanks for all answers since now.

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  • MVC3/Razor Client Validation Not firing

    - by Jason Gerstorff
    I am trying to get client validation working in MVC3 using data annotations. I have looked at similar posts including this MVC3 Client side validation not working for the answer. I'm using an EF data model. I created a partial class like this for my validations. [MetadataType(typeof(Post_Validation))] public partial class Post { } public class Post_Validation { [Required(ErrorMessage = "Title is required")] [StringLength(5, ErrorMessage = "Title may not be longer than 5 characters")] public string Title { get; set; } [Required(ErrorMessage = "Text is required")] [DataType(DataType.MultilineText)] public string Text { get; set; } [Required(ErrorMessage = "Publish Date is required")] [DataType(DataType.DateTime)] public DateTime PublishDate { get; set; } } My cshtml page includes the following. <h2>Create</h2> <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script> @using (Html.BeginForm()) { @Html.ValidationSummary(true) Post <div class="editor-label"> @Html.LabelFor(model => model.Title) </div> <div class="editor-field"> @Html.EditorFor(model => model.Title) @Html.ValidationMessageFor(model => model.Title) </div> <div class="editor-label"> @Html.LabelFor(model => model.Text) </div> <div class="editor-field"> @Html.EditorFor(model => model.Text) @Html.ValidationMessageFor(model => model.Text) Web Config: <appSettings> <add key="ClientValidationEnabled" value="true" /> <add key="UnobtrusiveJavaScriptEnabled" value="true" /> Layout: <head> <title>@ViewBag.Title</title> <link href="@Url.Content("~/Content/Site.css")" rel="stylesheet" type="text/css" /> <script src="@Url.Content("~/Scripts/jquery-1.4.4.min.js")" type="text/javascript"></script> So, the Multiline Text annotation works and creates a text area. But none of the validations work client side. I don't know what i might be missing. Any ideas?? i can post more information if needed. Thanks!

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  • The Math of a Jump in a 2D game.

    - by ONi
    I have been all around with this question and I can't find the correct answer! So, behold, the description of my question: I'm working in J2ME, I have my gameloop that do the following: public void run() { Graphics g = this.getGraphics(); while (running) { long diff = System.currentTimeMillis() - lastLoop; lastLoop = System.currentTimeMillis(); input(); this.level.doLogic(); render(g, diff); try { Thread.sleep(10); } catch (InterruptedException e) { stop(e); } } } so it's just a basic gameloop, the doLogic() function calls for all the logic functions of the characters in the scene and render(g, diff) calls the animateChar function of every character on scene, following this, the animChar function in the Character class sets up everything in the screen as this: protected void animChar(long diff) { this.checkGravity(); this.move((int) ((diff * this.dx) / 1000), (int) ((diff * this.dy) / 1000)); if (this.acumFrame > this.framerate) { this.nextFrame(); this.acumFrame = 0; } else { this.acumFrame += diff; } } This ensures me that everything must to move according to the time that the machine takes to go from cycle to cycle (remember it's a phone, not a gaming rig). I'm sure it's not the most efficient way to achieve this behavior so I'm totally open for criticism of my programming skills in the comments, but here my problem: When I make I character jump, what I do is that I put his dy to a negative value, say -200 and I set the boolean jumping to true, that makes the character go up, and then I have this function called checkGravity() that ensure that everything that goes up has to go down, checkGravity also checks for the character being over platforms so I will strip it down a little for the sake of your time: public void checkGravity() { if (this.jumping) { this.jumpSpeed += 10; if (this.jumpSpeed > 0) { this.jumping = false; this.falling = true; } this.dy = this.jumpSpeed; } if (this.falling) { this.jumpSpeed += 10; if (this.jumpSpeed > 200) this.jumpSpeed = 200; this.dy = this.jumpSpeed; if (this.collidesWithPlatform()) { this.falling = false; this.standing = true; this.jumping = false; this.jumpSpeed = 0; this.dy = this.jumpSpeed; } } } So, the problem is, that this function updates the dy regardless of the diff, making the characters fly like Superman in slow machines, and I have no idea how to implement the diff factor so that when a character is jumping, his speed decrement in a proportional way to the game speed. Can anyone help me fix this issue? or give me pointers on how to make a 2D Jump in J2ME the right way. Thank you very much for your time.

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  • How to have combobox take data from a child datasource

    - by SkollSunman
    I am trying to have a datagridview with two comboboxes, a company name and a supplier account number. When a company name is selected the relevant supplier account numbers (a company can have more than one supplier account) should be filtered for that company in that row. I have a datagridview with two bindingsources: supplierBindingSource and companyBindingSource and the Supplier account combobox uses the supplierBindingSource for its datasource and company name uses the companyBindingSource for its datasource. A company can have a supplier and/or customer account so the supplierBindingSource is a child or a companyBindingSource. The supplier accounts correctly filter based on the selected company name however when another company name is selected in another row all the supplier accounts are filtered for that company. Saving still works properly, regardless of what the combo box show but currently it is very confusing for a user to select a supplier account when the labels don't show what is being saved. Is it possible to have only the selected row to filter based on the company name rather than every row? EDIT: Thanks to the answer from http://social.msdn.microsoft.com/Forums/windows/en-US/b23d9e8f-a00a-49ba-adf5-52d87c1b2890/parent-child-comboboxes-in-datagridview I have been able to make some progress. The supplier account gets filtered when the drop down box is selected and restored to the full list when selection is finished. However now I am trying to have the company selected (and not filtered) when a supplier account is selected. The issue I've run into now is that I can get the companyID (which is the valuemember for the company combobox) but I cannot select the appropriate company without just setting the value of the combobox to the companyID which displays the companyID instead of the company name. Is there a way to select the company using the companyID while preserving the displaymember/valuemember dynamic? EDIT 2: The wall of text may be off putting. Some code to help elucidate my issue DataGridViewComboBoxCell dgcb2 = (DataGridViewComboBoxCell)sdgvSalesOrderLines[cmbSupplierName.Index, e.RowIndex]; var companyID = col.FirstOrDefault(c => c.AccountID == Convert.ToInt32(dgcb.Value)).CompanyID; dgcb2.Value = companyID.toString(); The second line gets the companyID and that works just fine, the final line sets the combobox to display the companyID whereas I would like it to set the valuemember value to companyID so that it would display the corresponding company name. I can set the second line to give me the company name instead but if the value of the combobox isn't the companyID then the supplier account cannot filter based on the company selected.

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  • How to play small sound file continuously in Silverlight?

    - by ash
    Hello, I have two questions regarding Silverlight's SoundPlay action and properties. My scenario is like: I have two story board: The first story board has an image and a sound file; when the silverlight application gets loaded, the sound starts to play automatically, but if someone clicks the image, the sound file will stop and the second storyboard will start with a new sound file. 1) My first question is how to stop the first sound file of first story board when the second story board starts with the second sound file. 2) My second question is how to play a sound file continuously; for example, in Silverlight we can play a story board continuously with RepeatBehavior="Forever"; but I cannot find a way to play my 10 second sound file forever or continuously. Note: I have attached a small XAML file to show what I am talking about; I am also stating that if instead of an image file, if there were a button, then I can stop the first music file after I click the button and start my second story board with a new sound file, but I would like to use image file instead of a button. Is it possible? If it is, how to do it? Therefore, please answer my following two questions or give big hint or website tutorial links on 1) How to stop the first sound file of first story board when the second story board starts with the second sound file ( When the clickable element is an image instead of a button) 2) How to play a 10 second sound file continuously? ............Code Snippet...................... XAML ............ <Grid x:Name="LayoutRoot" Background="Red"> <Button HorizontalAlignment="Left" Margin="212,0,0,111" VerticalAlignment="Bottom" Width="75" Content="Button" Click="onClick"/> <MediaElement x:Name="sound2_mp3" Height="0" HorizontalAlignment="Left" Margin="105,230,0,0" VerticalAlignment="Top" Width="0" Source="/sound2.mp3" Stretch="Fill"/> <MediaElement x:Name="sound1_mp1" Height="0" HorizontalAlignment="Left" Margin="190,164,0,0" VerticalAlignment="Top" Width="0" Source="/sound1.mp3" Stretch="Fill" AutoPlay="False"/> </Grid> ..................................................................................................................................................................................................................... using System; using System.Windows; using System.Windows.Controls; using System.Windows.Documents; using System.Windows.Ink; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Shapes; namespace testPrj { public partial class MainPage : UserControl { public MainPage() { // Required to initialize variables InitializeComponent(); } private void onClick(object sender, System.Windows.RoutedEventArgs e) { Storyboard1.Stop(); sound2_mp3.Stop(); sound1_mp1.Play(); } } } ...................................................................................................

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  • AsyncListViewAdapter + SimplePager, why is inactive pager clearing the table?

    - by Jaroslav Záruba
    I'm trying to make CellTable work together with AsyncListViewAdapter<T> and SimplePager<T>. The data gets displayed, but when the pager should be 'deaf' (meaning when all existing data are displayed) it still receives clicks and, more importantly, makes the displayed data go away. Instead of my data 'loading' indicator gets displayed, and it keep loading and loading... Obviously nothing gets loaded, as it doesn't even call the onRangeChanged handler. I went through the code-snippets in this thread, but I can't see anything suspicions on what I've been doing. Is there some obvious answer to a rookie mistake? I shrinked my variable names, hopefully it won't wrap too much. protected class MyAsyncAdapter extends AsyncListViewAdapter<DTO> { @Override protected void onRangeChanged(ListView<DTO> v) { /* * doesn't even get called on [go2start/go2end] click :( */ Range r = v.getRange(); fetchData(r.getStart(), r.getLength()); } } private void addTable() { // table: CellTable<DTO> table = new CellTable<DTO>(10); table.addColumn(new Column<DTO, String>(new TextCell()) { @Override public String getValue(DTO myDto) { return myDto.getName(); } }, "Name"); // pager: SimplePager<DTO> pager = new SimplePager<DTO>(table); table.setPager(pager); adapter = new MyAsyncAdapter(); adapter.addView(table); // does not make any difference: // adapter.updateDataSize(0, false); // adapter.updateDataSize(10, true); VerticalPanel vPanel = new VerticalPanel(); vPanel.add(table); vPanel.add(pager); RootLayoutPanel.get().add(vPanel); } // success-handler of my fetching AsyncCallback @Override public void onSuccess(List<DTO> data) { // AsyncCallback<List<DTO>> has start field adapter.updateViewData(start, data.size(), data); if(data.size() < length) adapter.updateDataSize(start + data.size(), true); } Regards J. Záruba

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  • Adding GestureOverlayView to my SurfaceView class, how to add to view hierarchy?

    - by Codejoy
    I was informed in a later answer that I have to add the GestureOverlayView I create in code to my view hierarchy, and I am not 100% how to do that. Below is the original question for completeness. I want my game to be able to recognize gestures. I have this nice SurfaceView class that I do an onDraw to draw my sprites, and I have a thread thats running it to call the onDraw etc . This all works great. I am trying to add the GestureOverlayView to this and it just isn't working. Finally hacked to where it doesn't crash but this is what i have public class Panel extends SurfaceView implements SurfaceHolder.Callback, OnGesturePerformedListener { public Panel(Context context) { theContext=context; mLibrary = GestureLibraries.fromRawResource(context, R.raw.myspells); GestureOverlayView gestures = new GestureOverlayView(theContext); gestures.setOrientation(gestures.ORIENTATION_VERTICAL); gestures.setEventsInterceptionEnabled(true); gestures.setGestureStrokeType(gestures.GESTURE_STROKE_TYPE_MULTIPLE); gestures.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)); //GestureOverlayView gestures = (GestureOverlayView) findViewById(R.id.gestures); gestures.addOnGesturePerformedListener(this); } ... ... onDraw... surfaceCreated(..); ... ... public void onGesturePerformed(GestureOverlayView overlay, Gesture gesture) { ArrayList<Prediction> predictions = mLibrary.recognize(gesture); // We want at least one prediction if (predictions.size() > 0) { Prediction prediction = predictions.get(0); // We want at least some confidence in the result if (prediction.score > 1.0) { // Show the spell Toast.makeText(theContext, prediction.name, Toast.LENGTH_SHORT).show(); } } } } The onGesturePerformed is never called. Their example has the GestureOverlay in the xml, I am not using that, my activity is simple: @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); Panel p = new Panel(this); setContentView(p); } So I am at a bit of a loss of the missing piece of information here, it doesn't call the onGesturePerformed and the nice pretty yellow "you are drawing a gesture" never shows up.

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  • WPF/C#: How to simplify the use of codes when calling a function (Generating Images)

    - by eibhrum
    I created a function in one of my application that allows to generate an image (in WPF) by getting the 'source path' from the database that I am using: public void ShowImageThumb() { try { cn = new MySqlConnection(); cn.ConnectionString = ConfigurationManager.AppSettings["MyConnection"]; cn.Open(); MySqlCommand cmd = new MySqlCommand(); cmd.Connection = cn; cmd.CommandType = CommandType.Text; cmd.CommandText = "SELECT thumb FROM album WHERE thumbNo=1"; MySqlDataAdapter adp = new MySqlDataAdapter(); adp.SelectCommand = cmd; DataTable dt = new DataTable(); adp.Fill(dt); MySqlDataReader r = cmd.ExecuteReader(); while (r.Read()) { BitmapImage bmi1 = new BitmapImage(new Uri(r[0].ToString(), UriKind.Relative)); image1.Source = bmi1; } r.Close(); cn.Close(); } catch (Exception err){ System.Windows.MessageBox.Show(err.Message); } finally { } } Take a look on my SQL statement. I put a WHERE thumbNo=1 which allows the function to get 1 record. You see, I do have at least 10 records - file paths listed in that table. I just wanna ask if there's a possible way to make my SQL statement something like this: SELECT thumb FROM album; while having this piece of code inserted in my function: BitmapImage bmi2 = new BitmapImage(new Uri(r["second record?"].ToString(), UriKind.Relative)); image2.Source = bmi2; //something like this BitmapImage bmi3 = new BitmapImage(new Uri(r["third record?"].ToString(), UriKind.Relative)); image3.Source = bmi3; //something like this and so on and so forth, without ending up creating 10 different functions for 10 records. ShowImageThumb2(); . . // will not do this . ShowImageThumb10(); Sorry for the lengthy post. I hope somebody could answer back. Thanks!

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  • Who calls the Destructor of the class when operator delete is used in multiple inheritance.

    - by dicaprio-leonard
    This question may sound too silly, however , I don't find concrete answer any where else. With little knowledge on how late binding works and virtual keyword used in inheritance. As in the code sample, when in case of inheritance where a base class pointer pointing to a derived class object created on heap and delete operator is used to deallocate the memory , the destructor of the of the derived and base will be called in order only when the base destructor is declared virtual function. Now my question is : 1) When the destructor of base is not virtual, why the problem of not calling derived dtor occur only when in case of using "delete" operator , why not in the case given below: derived drvd; base *bPtr; bPtr = &drvd; //DTOR called in proper order when goes out of scope. 2) When "delete" operator is used, who is reponsible to call the destructor of the class? The operator delete will have an implementation to call the DTOR ? or complier writes some extra stuff ? If the operator has the implementation then how does it looks like , [I need sample code how this would have been implemented]. 3) If virtual keyword is used in this example, how does operator delete now know which DTOR to call? Fundamentaly i want to know who calls the dtor of the class when delete is used. Sample Code class base { public: base() { cout<<"Base CTOR called"<<endl; } virtual ~base() { cout<<"Base DTOR called"<<endl; } }; class derived:public base { public: derived() { cout<<"Derived CTOR called"<<endl; } ~derived() { cout<<"Derived DTOR called"<<endl; } }; I'm not sure if this is a duplicate, I couldn't find in search. int main() { base *bPtr = new derived(); delete bPtr;// only when you explicitly try to delete an object return 0; }

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  • many-to-many performance concerns with fluent nhibernate.

    - by Ciel
    I have a situation where I have several many-to-many associations. In the upwards of 12 to 15. Reading around I've seen that it's generally believed that many-to-many associations are not 'typical', yet they are the only way I have been able to create the associations appropriate for my case, so I'm not sure how to optimize any further. Here is my basic scenario. class Page { IList<Tag> Tags { get; set; } IList<Modification> Modifications { get; set; } IList<Aspect> Aspects { get; set; } } This is one of my 'core' classes, and coincidentally one of my core tables. Virtually half of the objects in my code can have an IList<Page>, and some of them have IList<T> where T has its own IList<Page>. As you can see, from an object oriented standpoint, this is not really a problem. But from a database standpoint this begins to introduce a lot of junction tables. So far it has worked fine for me, but I am wondering if anyone has any ideas on how I could improve on this structure. I've spent a long time thinking and in order to achieve the appropriate level of association required, I cannot think of any way to improve it. The only thing I have come up with is to make intermediate classes for each object that has an IList<Page>, but that doesn't really do anything that the HasManyToMany does not already do except introduce another class. It does not extend the functionality and, from what I can tell, it does not improve performance. Any thoughts? I am also concerned about Primary Key limits in this scenario. Most everything needs to be able to have these properties, but the Pages cannot be unique to each object, because they are going to be frequently shared and joined between multiple objects. All relationships are one-sided. (That is, a Page has no knowledge of what owns it). Because of this, I also have no Inverse() mapped HasManyToMany collections. Also, I have read the similar question : Usage of ORMs like NHibernate when there are many associations - performance concerns But it really did not answer my concerns.

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  • How to obtain a pointer out of a C++ vtable?

    - by Josh Haberman
    Say you have a C++ class like: class Foo { public: virtual ~Foo() {} virtual DoSomething() = 0; }; The C++ compiler translates a call into a vtable lookup: Foo* foo; // Translated by C++ to: // foo->vtable->DoSomething(foo); foo->DoSomething(); Suppose I was writing a JIT compiler and I wanted to obtain the address of the DoSomething() function for a particular instance of class Foo, so I can generate code that jumps to it directly instead of doing a table lookup and an indirect branch. My questions are: Is there any standard C++ way to do this (I'm almost sure the answer is no, but wanted to ask for the sake of completeness). Is there any remotely compiler-independent way of doing this, like a library someone has implemented that provides an API for accessing a vtable? I'm open to completely hacks, if they will work. For example, if I created my own derived class and could determine the address of its DoSomething method, I could assume that the vtable is the first (hidden) member of Foo and search through its vtable until I find my pointer value. However, I don't know a way of getting this address: if I write &DerivedFoo::DoSomething I get a pointer-to-member, which is something totally different. Maybe I could turn the pointer-to-member into the vtable offset. When I compile the following: class Foo { public: virtual ~Foo() {} virtual void DoSomething() = 0; }; void foo(Foo *f, void (Foo::*member)()) { (f->*member)(); } On GCC/x86-64, I get this assembly output: Disassembly of section .text: 0000000000000000 <_Z3fooP3FooMS_FvvE>: 0: 40 f6 c6 01 test sil,0x1 4: 48 89 74 24 e8 mov QWORD PTR [rsp-0x18],rsi 9: 48 89 54 24 f0 mov QWORD PTR [rsp-0x10],rdx e: 74 10 je 20 <_Z3fooP3FooMS_FvvE+0x20> 10: 48 01 d7 add rdi,rdx 13: 48 8b 07 mov rax,QWORD PTR [rdi] 16: 48 8b 74 30 ff mov rsi,QWORD PTR [rax+rsi*1-0x1] 1b: ff e6 jmp rsi 1d: 0f 1f 00 nop DWORD PTR [rax] 20: 48 01 d7 add rdi,rdx 23: ff e6 jmp rsi I don't fully understand what's going on here, but if I could reverse-engineer this or use an ABI spec I could generate a fragment like the above for each separate platform, as a way of obtaining a pointer out of a vtable.

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