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  • Strage character encoding problem with Eclipse / Spring / Tomcat 6

    - by Czar
    Hi, I have been trying things all da but can't get a proper solution. My problem is: I am developing a Spring MVC based app in my local Tomcat. My MYSQl database has UTF-8 encoding set, all content in there displays properly when using phpMyAdmin. Also the output in LOG files using log4j in catalina.out works fine. My JSP pages are configured by <!-- encoding --> <%@ page contentType="text/html; charset=UTF-8" %> <%@ page pageEncoding="UTF-8" %> Also showing data on my JSP works fine. I can also send data from my Controller without any DB intereference using special chars, e.g. String str = "UTF-8 Test: Ä Ö Ü ß è é â"; logger.debug(str); mav.addObject("utftest", str); That displays correctly in log and on jsp page in browser. BUT: When having special chars directly in my JSP file, e.g. for text in headers, this does not work. FF and Google Chrome display strange chars but report the page to be UTF-8. When switching to Latin, the chars just get more and more strange. Same problem when showing text tokens from my messages.properties file, although Eclipse says when right-clicking that UTF-8 will be used. I am a little it lost and don't know where to check now. Summary: DB storage is fine DB output on JSP is fine Output on JSP directly form controller is fine even reading in form forms is fine .properties files and JSP text is not fine !!! Any ideas? I really appreciate and tips.

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  • Which technology is best suited to store and query a huge readonly graph?

    - by asmaier
    I have a huge directed graph: It consists of 1.6 million nodes and 30 million edges. I want the users to be able to find all the shortest connections (including incoming and outgoing edges) between two nodes of the graph (via a web interface). At the moment I have stored the graph in a PostgreSQL database. But that solution is not very efficient and elegant, I basically need to store all the edges of the graph twice (see my question PostgreSQL: How to optimize my database for storing and querying a huge graph). It was suggested to me to use a GraphDB like neo4j or AllegroGraph. However the free version of AllegroGraph is limited to 50 million nodes and also has a very high-level API (RDF), which seems too powerful and complex for my problem. Neo4j on the other hand has only a very low level API (and the python interface is not mature yet). Both of them seem to be more suited for problems, where nodes and edges are frequently added or removed to a graph. For a simple search on a graph, these GraphDBs seem to be too complex. One idea I had would be to "misuse" a search engine like Lucene for the job, since I'm basically only searching connections in a graph. Another idea would be, to have a server process, storing the whole graph (500MB to 1GB) in memory. The clients could then query the server process and could transverse the graph very quickly, since the graph is stored in memory. Is there an easy possibility to write such a server (preferably in Python) using some existing framework? Which technology would you use to store and query such a huge readonly graph?

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  • Create an anonymous type object from an arbitrary text file

    - by Robert Harvey
    I need a sensible way to draw arbitrary text files into a C# program, and produce an arbitrary anonymous type object, or perhaps a composite dictionary of some sort. I have a representative text file that looks like this: adapter 1: LPe11002 Factory IEEE: 10000000 C97A83FC Non-Volatile WWPN: 10000000 C93D6A8A , WWNN: 20000000 C93D6A8A adapter 2: LPe11002 Factory IEEE: 10000000 C97A83FD Non-Volatile WWPN: 10000000 C93D6A8B , WWNN: 20000000 C93D6A8B Is there a way to get this information into an anonymous type object or some similar structure? The final anonymous type might look something like this, if it were composed in C# by hand: new { adapter1 = new { FactoryIEEE = "10000000 C97A83FC", Non-VolatileWWPN = "10000000 C93D6A8A", WWNN = "20000000 C93D6A8A" } adapter2 = new { FactoryIEEE = "10000000 C97A83FD", Non-VolatileWWPN = "10000000 C93D6A8B", WWNN = "20000000 C93D6A8B" } } Note that, as the text file's content is arbitrary (i.e. the keys could be anything), a specialized solution (e.g. that looks for names like "FactoryIEEE") won't work. However, the structure of the file will always be the same (i.e. indentation for groups, colons and commas as delimiters, etc). Or maybe I'm going about this the wrong way, and you have a better idea?

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  • batch file to merge .js files from subfolders into one combined file

    - by Andrew Johns
    I'm struggling to get this to work. Plenty of examples on the web, but they all do something just slightly different to what I'm aiming to do, and every time I think I can solve it, I get hit by an error that means nothing to me. After giving up on the JSLint.VS plugin, I'm attempting to create a batch file that I can call from a Visual Studio build event, or perhaps from cruise control, which will generate JSLint warnings for a project. The final goal is to get a combined js file that I can pass to jslint, using: cscript jslint.js < tmp.js which would validate that my scripts are ready to be combined into one file for use in a js minifier, or output a bunch of errors using standard output. but the js files that would make up tmp.js are likely to be in multiple subfolders in the project, e.g: D:\_projects\trunk\web\projectname\js\somefile.debug.js D:\_projects\trunk\web\projectname\js\jquery\plugins\jquery.plugin.js The ideal solution would be to be able to call a batch file along the lines of: jslint.bat %ProjectPath% and this would then combine all the js files within the project into one temp js file. This way I would have flexibility in which project was being passed to the batch file. I've been trying to make this work with copy, xcopy, type, and echo, and using a for do loop, with dir /s etc, to make it do what I want, but whatever I try I get an error.

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  • Multiple connections in a single SSH SOCKS 5 Proxy

    - by Elie Zedeck
    Hey guys, My fist question here on Stackoverflow: What should I need to do so that the SSH SOCKS 5 Proxy (SSH2) will allow multiple connections? What I have noticed, is that when I load a page in Firefox (already configured to use the SOCKS 5 proxy), it loads everything one by one. It can be perceived by bare eyes, and I also confirm that through the use of Firebug's NET tab, which logs the connections that have been made. I have already configure some of the directives in the about:config page, like pipeline, persistent proxy connections, and a few other things. But I still get this kind of sequential load of resources, which is noticeably very slow. network.http.pipelining;true network.http.pipelining.maxrequests;8 network.http.pipelining.ssl;true network.http.proxy.pipelining;true network.http.max-persistent-connections-per-proxy;100 network.proxy.socks_remote_dns;true My ISP sucks because during the day, it intentionally breaks connections on a random basis. And so, it is impossible to actually accomplish meaningful works without the need of a lot of browser refresh or hitting F5 key. So, that is why I started to find solutions to this. The SSH's dynamic port forwarding is the best solution I find to date, because it has some pretty good compression which saves a lot of useless traffic, and is also secure. The only thing remaining is to get it to have multiple connections running in it. Thanks for all the inputs.

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  • Kohana 3, themes outside application.

    - by Marek
    Hi all I read http://forum.kohanaframework.org/comments.php?DiscussionID=5744&page=1#Item_0 and I want to use similar solution, but with db. In my site controller after(): $theme = $page->get_theme_name(); //Orange Kohana::set_module_path('themes', Kohana::get_module_path('themes').'/'.$theme); $this->template = View::factory('layout') I checked with firebug: fire::log(Kohana::get_module_path('themes')); // D:\tools\xampp\htdocs\kohana\themes/Orange I am sure that path exists. I have directly in 'Orange' folder 'views' folder with layout.php file. But I am getting: The requested view layout could not be found Extended Kohana_Core is just: public static function get_module_path($module_key) { return self::$_modules[$module_key]; } public static function set_module_path($module_key, $path) { self::$_modules[$module_key] = $path; } Could anybody help me with solving that issue? Maybe it is a .htaccess problem: # Turn on URL rewriting RewriteEngine On # Put your installation directory here: # If your URL is www.example.com/kohana/, use /kohana/ # If your URL is www.example.com/, use / RewriteBase /kohana/ # Protect application and system files from being viewed RewriteCond $1 ^(application|system|modules) # Rewrite to index.php/access_denied/URL RewriteRule ^(.*)$ / [PT,L] RewriteRule ^(media) - [PT,L] RewriteRule ^(themes) - [PT,L] # Allow these directories and files to be displayed directly: # - index.php (DO NOT FORGET THIS!) # - robots.txt # - favicon.ico # - Any file inside of the images/, js/, or css/ directories RewriteCond $1 ^(index\.php|robots\.txt|favicon\.ico|static) # No rewriting RewriteRule ^(.*)$ - [PT,L] # Rewrite all other URLs to index.php/URL RewriteRule ^(.*)$ index.php/$1 [PT,L] Could somebody help? What I am doing wrong? Regards

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  • What can cause Windows to unhook a low level (global) keyboard hook?

    - by Davy8
    We have some global keyboard hooks installed via SetWindowsHookEx with WH_KEYBOARD_LL that appear to randomly get unhooked by Windows. We verified that they hook was no longer attached because calling UnhookWindowsHookEx on the handle returns false. (Also verified that it returns true when it was working properly) There doesn't seem to be a consistent repro, I've heard that they can get unhooked due to timeouts or exceptions getting thrown, but I've tried both just letting it sit on a breakpoint in the handling method for over a minute, as well as just throwing a random exception (C#) and it still appears to work. In our callback we quickly post to another thread, so that probably isn't the issue. I've read about solutions in Windows 7 for setting the timeout higher in the registry because Windows 7 is more aggressive about the timeouts apparently (we're all running Win7 here, so not sure if this occurs on other OS's) , but that doesn't seem like an ideal solution. I've considered just having a background thread running to refresh the hook every once in a while, which is hackish, but I don't know of any real negative consequences of doing that, and it seems better than changing a global Windows registry setting. Any other suggestions or solutions? The delegates are not being GC'd since they're static members, which is one cause that I've read about.

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  • java serialization problems with different JVMs

    - by Alberto
    I am having trouble using serialization in Java. I've searched the web for a solution but haven't found an answer yet. The problem is this - I have a Java library (I have the code and I export it to an archive prior to executing the code) which I need to use with two differents JVMs. One JVM is on the server (Ubuntu, running Java(TM) JRE SE Runtime Environment (build 1.7.0_09-b05)) and the other on Android 2.3.3. I compiled the library in Java 1.6. Now, I am trying to import to the client, an object exported from the server, but I receive this error: java.io.InvalidClassException: [Lweka.classifiers.functions.MultilayerPerceptron$NeuralEnd;; Incompatible class (SUID): [Lweka.classifiers.functions.MultilayerPerceptron$NeuralEnd;: static final long serialVersionUID =-359311387972759020L; but expected [Lweka.classifiers.functions.MultilayerPerceptron$NeuralEnd;: static final long serialVersionUID =1920571045915494592L; I do have an explicit serial version UID declared on the class MultilayerPerceptron$NeuralEnd, like this: protected class NeuralEnd extends NeuralConnection { private static final long serialVersionUID = 7305185603191183338L; } Where NeuralConnection implements the java.io.Serializable interface. If I do a serialver on MultilayerPerceptron$NeuralEnd I receive the serialVersionUID which I declared. So, why have both JVMs changed this value? Can you help me? Thanks, Alberto

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  • Entity framework entity class mapping with plain .net class

    - by Elan
    I have following in entity framework Table - Country Fields List item Country_ID Dialing_Code ISO_Alpha2 ISO_Alpha3 ISO_Full I would like to map only selected fields from this entity model to my domain class. My domain model class is public class DomainCountry { public int Country_ID { get; set; } public string Dialing_Code { get; set; } public string ISO_3166_1_Alpha_2 { get; set; } } The following will work however insert or update is not possible. In order to get insert or update we need to use ObjectSet< but it will not support in my case. IQueryable<DomainCountry> countries = context.Countries.Select( c => new DomainCountry { Country_ID = c.Country_Id, Dialing_Code = c.Dialing_Code, ISO_3166_1_Alpha_2 = c.ISO_3166_1_Alpha_2 }); It will be really fantastic could someone provide a nice solution for this. Ideally it will be kind of proxy class which will support all the futures however highly customizable i.e. only the columns we want to expose to the outer world

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  • review of a codility test - pair_sum_even_count

    - by geoaxis
    I recently took an online test on codility as part of a recruitment process. I was given two simple problems to solve in 1 hour. For those who don't know codility, its an online coding test site where you can solve ACM style problems in many different languages. if you have 30 or so mins then check this http://codility.com/demo/run/ My weapon of choice is usually Java. So on of the problems I have is as follows (I will try to remember, should have taken a screenshot) Lets say you have array A[0]=1 A[1]=-1 ....A[n]=x Then what would be the smartest way to find out the number of times when A[i]+A[j] is even where i < j So if we have {1,2,3,4,5} we have 1+3 1+5 2+4 3+5 = 4 pairs which are even The code I wrote was some thing along the lines int sum=0; for(int i=0;i<A.length-1;i++){ for (int j=i+1;j<A.length;j++){ if( ((A[i]+A[j])%2) == 0 && i<j) { sum++; } } } There was one more restriction that if the number of pairs is greater than 1e9 then it should retrun -1, but lets forget it. Can you suggest a better solution for this. The number of elements won't exceed 1e9 in normal cases. I think I got 27 points deducted for the above code (ie it's not perfect). Codility gives out a detailed assessment of what went wrong, I don't have that right now.

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  • Parsing / Extracting Text from String in Rails?

    - by user641116
    I have a string in Rails, e.g. "This is a Twitter message. #books War & Peace by Leo Tolstoy. I love this book!", and I want to parse the text and extract only certain phrases, like "War & Peace by Leo Tolstoy". Is this a matter of using Regex and lifting the text between "#books" to "."? What if there's no structure to the message, like: "This is a Twitter message #books War & Peace by Leo Tolstoy I love this book!" or "This is a Twitter message. I love the book War & Peace by Leo Tolstoy #books" How can I reliably pull the phrase "War & Peace by Leo Tolstoy" without knowing the phrase ex ante. Are there any gems, methods, etc. that can help me do this? At the very least, what would you call what I'm trying to do? It will help me search for a solution on Google. I've tried a few searches on "parsing" with no luck.

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  • wix The directory is in the user profile but is not listed in the RemoveFile table

    - by Venkat S. Rao
    I have the following configuration to delete and copy a file from WIX. <Directory Id='TARGETDIR' Name='SourceDir'> ... <Directory Id="AppDataFolder" Name="AppDataFolder"> <Directory Id="GleasonAppData" Name="Gleason" > <Directory Id="GleasonStudioAppData" Name="GleasonStudio"> <Directory Id="DatabaseAppData" Name ="Database"> <Directory Id="UserSandboxesAppData" Name="UserSandboxes" /> </Directory> </Directory> </Directory> </Directory> </Directory> <DirectoryRef Id="UserSandboxesAppData"> <Component Id="comp_deleteBackup" Guid="1f159f49-3029-4f46-b194-e42aabd40844"> <RemoveFile Id="RemoveBackup" Directory="UserSandboxesAppData" Name="DevelopmentBackUp.FDB" On="install" /> <RegistryKey Root="HKCU" Key="Software\Gleason\Database\RemoveBackup"> <RegistryValue Value="Removed" Type="string" KeyPath="yes" /> </RegistryKey> </Component> <Component Id="comp_createBackup" Guid="557badef-6d77-4c4e-aa5f-8d88cb5ef735"> <CopyFile Id="DBBackup" DestinationDirectory="UserSandboxesAppData" DestinationName="DevelopmentBackUp.FDB" SourceDirectory="UserSandboxesAppData" SourceName="Development.FDB" /> <RegistryKey Root="HKCU" Key="Software\Gleason\Database\CopyBackup"> <RegistryValue Value="Copied" Type="string" KeyPath="yes" /> </RegistryKey> </Component> </DirectoryRef> I get 4 errors related to ICE64--The directory 'xxx' is in the user profile but is not listed in the RemoveFile table. xxx={UserSandboxesAppData, DatabaseAppData, GleasonStudioAppData, GleasonAppData} Someone else had a very similar problem here: Directory xx is in the user profile but is not listed in the RemoveFile table. . But that solution did not help me. What do I need to change? Thank You, Venkat Rao

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  • matlab precision determinant problem

    - by ldigas
    I have the following program format compact; format short g; clear; clc; L = 140; J = 77; Jm = 10540; G = 0.8*10^8; d = L/3; for i=1:500000 omegan=1.+0.0001*i; a(1,1) = ((omegan^2)*(Jm/(G*J))*d^2)-2; a(1,2) = 2; a(1,3) = 0; a(1,4) = 0; a(2,1) = 1; a(2,2) = ((omegan^2)*(Jm/(G*J))*d^2)-2; a(2,3) = 1; a(2,4) = 0; a(3,1) = 0; a(3,2) = 1; a(3,3) = ((omegan^2)*(Jm/(G*J))*d^2)-2; a(3,4) = 1; a(4,1) = 0; a(4,2) = 0; a(4,3) = 2; a(4,4) = ((omegan^2)*(Jm/(G*J))*d^2)-2; if(abs(det(a))<1E-10) sprintf('omegan= %8.3f det= %8.3f',omegan,det(a)) end end Analytical solution of the above system, and the same program written in fortran gives out values of omegan equal to 16.3818 and 32.7636 (fortran values; analytical differ a little, but they're there somewhere). So, now I'm wondering ... where am I going wrong with this ? Why is matlab not giving the expected results ? (this is probably something terribly simple, but it's giving me headaches)

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  • Designing a fluent Javascript interface to abstract away the asynchronous nature of AJAX

    - by Anurag
    How would I design an API to hide the asynchronous nature of AJAX and HTTP requests, or basically delay it to provide a fluid interface. To show an example from Twitter's new Anywhere API: // get @ded's first 20 statuses, filter only the tweets that // mention photography, and render each into an HTML element T.User.find('ded').timeline().first(20).filter(filterer).each(function(status) { $('div#tweets').append('<p>' + status.text + '</p>'); }); function filterer(status) { return status.text.match(/photography/); } vs this (asynchronous nature of each call is clearly visible) T.User.find('ded', function(user) { user.timeline(function(statuses) { statuses.first(20).filter(filterer).each(function(status) { $('div#tweets').append('<p>' + status.text + '</p>'); }); }); }); It finds the user, gets their tweet timeline, filters only the first 20 tweets, applies a custom filter, and ultimately uses the callback function to process each tweet. I am guessing that a well designed API like this should work like a query builder (think ORMs) where each function call builds the query (HTTP URL in this case), until it hits a looping function such as each/map/etc., the HTTP call is made and the passed in function becomes the callback. An easy development route would be to make each AJAX call synchronous, but that's probably not the best solution. I am interested in figuring out a way to make it asynchronous, and still hide the asynchronous nature of AJAX.

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  • log4net creates log file but does not write to it (windows service in C#)

    - by user1825172
    I am trying to use basic logging for a windows service. I added the reference to log4net I added the following in AssemblyInfo.cs: [assembly: log4net.Config.XmlConfigurator(Watch = true)] I added the following to my App.config: <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net, Version=1.2.10.0, Culture=neutral, PublicKeyToken=1b44e1d426115821" requirePermission="false" /> </configSections> <!-- Log4net Logging Setup --> <log4net> <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender,log4net"> <file value="c:\\CGSD\\log\\logfile.txt" /> <appendToFile value="true" /> <lockingModel type="log4net.Appender.FileAppender+MinimalLock" /> <layout type="log4net.Layout.PatternLayout"> <conversionPattern value="%date [%thread] %level %logger - %message%newline" /> </layout> <filter type="log4net.Filter.LevelRangeFilter"> <levelMin value="INFO" /> <levelMax value="FATAL" /> </filter> </appender> <root> <level value="ALL"/> <appender-ref ref="RollingFileAppender"/> </root> </log4net> </configuration> I have the following code in my service: log4net.Config.XmlConfigurator.Configure(); log4net.ILog log = log4net.LogManager.GetLogger(typeof(Program)); log.Debug("test"); the file c:\CGSD\log\logfile.txt is created but nothing is ever written to it. i've been thru the forums all day trying to trac this one down, but if i overlooked an already posted solution i apologize. thx!

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  • Instantiate type variable in Haskell

    - by danportin
    EDIT: Solved. I was unware that enabling a language extension in the source file did not enable the language extension in GHCi. The solution was to :set FlexibleContexts in GHCi. I recently discovered that type declarations in classes and instances in Haskell are Horn clauses. So I encoded the arithmetic operations from The Art of Prolog, Chapter 3, into Haskell. For instance: fac(0,s(0)). fac(s(N),F) :- fac(N,X), mult(s(N),X,F). class Fac x y | x -> y instance Fac Z (S Z) instance (Fac n x, Mult (S n) x f) => Fac (S n) f pow(s(X),0,0) :- nat(X). pow(0,s(X),s(0)) :- nat(X). pow(s(N),X,Y) :- pow(N,X,Z), mult(Z,X,Y). class Pow x y z | x y -> z instance (N n) => Pow (S n) Z Z instance (N n) => Pow Z (S n) (S Z) instance (Pow n x z, Mult z x y) => Pow (S n) x y In Prolog, values are insantiated for (logic) variable in a proof. However, I don't understand how to instantiate type variables in Haskell. That is, I don't understand what the Haskell equivalent of a Prolog query ?-f(X1,X2,...,Xn) is. I assume that :t undefined :: (f x1 x2 ... xn) => xi would cause Haskell to instantiate xi, but this gives a Non type-variable argument in the constraint error, even with FlexibleContexts enabled.

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  • How to create minidump of a .NET process when a certain first chance exception occurs.

    - by mark
    Dear ladies and sirs. My application throws InvalidCastException in the QA environment, something I cannot reproduce in development. I wish to obtain the minidump at the exception moment. I know about adplus, but I am not sure how to use it so that it creates the minidump when InvalidCastException is thrown. Apparently, it does not distinguish one .NET exception from another. May be I am wrong and there is a way. Or, there is another tool to do it. Preferably free one. Anyway, can anyone advice how to handle this issue? Thanks. UPDATE The build is a Debug build in both QA and dev. However, QA runs complex scenarios made possible in the lab, which devs cannot reproduce. Hence I need an ability to make dump when running in QA. I can modify the code and create minidump from code. However, I wish for a more flexible solution, the one not requiring to modify the code every time an issue like this occurs.

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  • CSRF Protection in AJAX Requests using MVC2

    - by mnemosyn
    The page I'm building depends heavily on AJAX. Basically, there is just one "page" and every data transfer is handled via AJAX. Since overoptimistic caching on the browser side leads to strange problems (data not reloaded), I have to perform all requests (also reads) using POST - that forces a reload. Now I want to prevent the page against CSRF. With form submission, using Html.AntiForgeryToken() works neatly, but in AJAX-request, I guess I will have to append the token manually? Is there anything out-of-the box available? My current attempt looks like this: I'd love to reuse the existing magic. However, HtmlHelper.GetAntiForgeryTokenAndSetCookie is private and I don't want to hack around in MVC. The other option is to write an extension like public static string PlainAntiForgeryToken(this HtmlHelper helper) { // extract the actual field value from the hidden input return helper.AntiForgeryToken().DoSomeHackyStringActions(); } which is somewhat hacky and leaves the bigger problem unsolved: How to verify that token? The default verification implementation is internal and hard-coded against using form fields. I tried to write a slightly modified ValidateAntiForgeryTokenAttribute, but it uses an AntiForgeryDataSerializer which is private and I really didn't want to copy that, too. At this point it seems to be easier to come up with a homegrown solution, but that is really duplicate code. Any suggestions how to do this the smart way? Am I missing something completely obvious?

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  • Specification Pattern and Boolean Operator Precedence

    - by Anders Nielsen
    In our project, we have implemented the Specification Pattern with boolean operators (see DDD p 274), like so: public abstract class Rule { public Rule and(Rule rule) { return new AndRule(this, rule); } public Rule or(Rule rule) { return new OrRule(this, rule); } public Rule not() { return new NotRule(this); } public abstract boolean isSatisfied(T obj); } class AndRule extends Rule { private Rule one; private Rule two; AndRule(Rule one, Rule two) { this.one = one; this.two = two; } public boolean isSatisfied(T obj) { return one.isSatisfied(obj) && two.isSatisfied(obj); } } class OrRule extends Rule { private Rule one; private Rule two; OrRule(Rule one, Rule two) { this.one = one; this.two = two; } public boolean isSatisfied(T obj) { return one.isSatisfied(obj) || two.isSatisfied(obj); } } class NotRule extends Rule { private Rule rule; NotRule(Rule obj) { this.rule = obj; } public boolean isSatisfied(T obj) { return !rule.isSatisfied(obj); } } Which permits a nice expressiveness of the rules using method-chaining, but it doesn't support the standard operator precedence rules of which can lead to subtle errors. The following rules are not equivalent: Rule<Car> isNiceCar = isRed.and(isConvertible).or(isFerrari); Rule<Car> isNiceCar2 = isFerrari.or(isRed).and(isConvertible); The rule isNiceCar2 is not satisfied if the car is not a convertible, which can be confusing since if they were booleans isRed && isConvertible || isFerrari would be equivalent to isFerrari || isRed && isConvertible I realize that they would be equivalent if we rewrote isNiceCar2 to be isFerrari.or(isRed.and(isConvertible)), but both are syntactically correct. The best solution we can come up with, is to outlaw the method-chaining, and use constructors instead: OR(isFerrari, AND(isConvertible, isRed)) Does anyone have a better suggestion?

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  • Does this use of Monitor.Wait/Pulse have a race condition?

    - by jw
    I have a simple producer/consumer scenario, where there is only ever a single item being produced/consumed. Also, the producer waits for the worker thread to finish before continuing. I realize that kind of obviates the whole point of multithreading, but please just assume it really needs to be this way (: This code doesn't compile, but I hope you get the idea: // m_data is initially null // This could be called by any number of producer threads simultaneously void SetData(object foo) { lock(x) // Line A { assert(m_data == null); m_data = foo; Monitor.Pulse(x) // Line B while(m_data != null) Monitor.Wait(x) // Line C } } // This is only ever called by a single worker thread void UseData() { lock(x) // Line D { while(m_data == null) Monitor.Wait(x) // Line E // here, do something with m_data m_data = null; Monitor.Pulse(x) // Line F } } Here is the situation that I am not sure about: Suppose many threads call SetData() with different inputs. Only one of them will get inside the lock, and the rest will be blocked on Line A. Suppose the one that got inside the lock sets m_data and makes its way to Line C. Question: Could the Wait() on Line C allow another thread at Line A to obtain the lock and overwrite m_data before the worker thread even gets to it? Supposing that doesn't happen, and the worker thread processes the original m_data, and eventually makes its way to Line F, what happens when that Pulse() goes off? Will only the thread waiting on Line C be able to get the lock? Or will it be competing with all the other threads waiting on Line A as well? Essentially, I want to know if Pulse()/Wait() communicate with each other specially "under the hood" or if they are on the same level with lock(). The solution to these problems, if they exist, is obvious of course - just surround SetData() with another lock - say, lock(y). I'm just curious if it's even an issue to begin with.

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  • using JQuery and Prototype in the same page

    - by Don
    Hi, Several of my pages use both JQuery and Protoype. Since I upgraded to version 1.3 of JQuery this appears to be causing problems, because both libraries define a function named '$'. JQuery provides a function noConflict() which relinquishes control of $ to other libraries that may be using it. So it seems like I need to go through all my pages that look like this: <head> <script type="text/javascript" src="/obp/js/prototype.js"></script> <script type="text/javascript" src="/obp/js/jquery.js"></script> </head> and change them to look like this: <head> <script type="text/javascript" src="/obp/js/prototype.js"></script> <script type="text/javascript" src="/obp/js/jquery.js"></script> <script type="text/javascript"> jQuery.noConflict(); var $j = jQuery; </script> </head> I should then be able to use '$' for Prototype and '$j' (or 'jQuery') for JQuery. I'm not entirely happy about duplicating these 2 lines of code in every relevant page, and expect that at some point somebody is likely to forget to add them to a new page. I'd prefer to be able to do the following Create a file jquery-noconflict.js which "includes" jquery.js and the 2 lines of code shown above Import jquery-noconflict.js (instead of jquery.js) in all my JSP/HTML pages However, I'm not sure if it's possible to include one JS file in another, in the manner I've described? Of course an alternate solution is simply to add the 2 lines of code above to jquery.js directly, but if I do that I'll need to remember to do it every time I upgrade JQuery. Thanks in advance, Don

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  • ActiveRecord table inheritence using set_table_names

    - by Jinyoung Kim
    Hi, I'm using ActiveRecord in Ruby on Rails. I have a table named documents(Document class) and I want to have another table data_documents(DataDocument) class which is effectively the same except for having different table name. In other words, I want two tables with the same behavior except for table name. class DataDocument < Document #set_table_name "data_documents" self.table_name = "data_documents" end My solution was to use class inheritance as above, yet this resulted in inconsistent SQL statement for create operation where there are both 'documents' table and 'data_documents' table. Can you figure out why and how I can make it work? >> DataDocument.create(:did=>"dd") ActiveRecord::StatementInvalid: Mysql::Error: Unknown column 'data_documents.did' in 'where clause': SELECT `documents`.id FROM `documents` WHERE (`data_documents`.`did` = BINARY 'dd') LIMIT 1 from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/mysql_adapter.rb:320:in `execute' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/mysql_adapter.rb:595:in `select' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/database_statements.rb:7:in `select_all_without_query_cache' from /Users/lifidea/.gem/ruby/1.8/gems/activerecord-2.3.2/lib/active_record/connection_adapters/abstract/query_cache.rb:62:in `select_all'

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  • Stock management of assemblies and its sub parts (relations)

    - by The Disintegrator
    I have to track the stock of individual parts and kits (assemblies) and can't find a satisfactory way of doing this. Sample bogus and hyper simplified database: Table prod: prodID 1 prodName Flux capacitor prodCost 900 prodPrice 1350 (900*1.5) prodStock 3 - prodID 2 prodName Mr Fusion prodCost 300 prodPrice 600 (300*2) prodStock 2 - prodID 3 prodName Time travel kit prodCost 1650 (1350+300) prodPrice 2145 (1650*1.3) prodStock 2 Table rels relID 1 relSrc 1 (Flux capacitor) relType 4 (is a subpart of) relDst 3 (Time travel kit) - relID 2 relSrc 2 (Mr Fusion) relType 4 (is a subpart of) relDst 3 (Time travel kit) prodPrice: it's calculated based on the cost but not in a linear way. In this example for costs of 500 or less, the markup is a 200%. For costs of 500-1000 the markup is 150%. For costs of 1000+ the markup is 130% That's why the time travel kit is much cheaper than the individual parts prodStock: here is my problem. I can sell kits or the individual parts, So the stock of the kits is virtual. The problem when I buy: Some providers sell me the Time Travel kit as a whole (with one barcode) and some sells me the individual parts (with a different barcode) So when I load the stock I don't know how to impute it. The problem when I sell: If I only sell kits, calculate the stock would be easy: "I have 3 Flux capacitors and 2 Mr Fusions, so I have 2 Time travel kits and a Flux Capacitor" But I can sell Kits or individual parts. So, I have to track the stock of the individual parts and the possible kits at the same time (and I have to compensate for the sell price) Probably this is really simple, but I can't see a simple solution. Resuming: I have to find a way of tracking the stock and the database/program is the one who has to do it (I cant ask the clerk to correct the stock) I'm using php+MySql. But this is more a logical problem than a programing one

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  • Best pratice: How do I implement a list that can be rendered both server-side and client-side?

    - by André Pena
    Technologies involved: ASP.NET Web-forms Javascript (jQuery for instance) Case To make it clearer let's give the Stackoverflow authors list as an example. This list can be manipulated at client-side. I can search, page and so forth. So obviously we would need to call jQuery.ajax to retrieve the HTML of each page given a search. Alright. Now this leaves me with the first question: What is the best way to render the response for the jQuery.ajax at server-side? I can't use templates I suppose, so the most obvious solution I think is to create the HTML tags as server-controls and render them as the result of an ASHX request? Is this is best approach? Nice. That solved we have yet another problem: When the user first enters the Authors List the first list page should already come from the server completely rendered alright? Of course we could render the first page as well as an ajax call but I don't think it's better. This time I CAN use templates to render the list but this template couldn't be reused in case 1. What do I do? Now the final question: Now we have 2 rendering strategies: 1) Client and 2) Server. How do I reuse code for the 2 renderings? What are the best pratices for solving these problems?

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  • Custom Repeater with hiractial Databinding

    - by Dooie
    Im using a Custom NestedRepeater Control for ASP.NET which can be found on code project The source is in c# which i have converted to vb and plugged into my solution, so far so good. The problem, im having is databinding to the repeater, my code behind looks like this... '' get all pages Dim navPages As DataSet = Navigation.getMenuStructure() navPages.Relations.Add(navPages.Tables(0).Columns("ID"), navPages.Tables(0).Columns("ParentID")) NestedRepeaterNavigation.RelationName = RelationName NestedRepeaterNavigation.DataSource = navPages NestedRepeaterNavigation.RowFilterTop = "ParentID is null" NestedRepeaterNavigation.DataBind() Then in the item template of my custom repeater im trying the following... <ItemTemplate> <img src="/pix.gif" height="10" width="<%#(Container.Depth * 10)%>"> <%# (Container.DataItem as DataRow)["DESCRIPTION"]%> <%# (Container.NbChildren != 0 ? "<small><i>(" + Container.NbChildren.ToString() +")</i></small>" "") %><small><i></i></small> </ItemTemplate> The databinding falls over; firstly that 'as DataRow' says it was expecting an ')'. And secondly that '!=' identifier expected. Is this due to the translation from c#, should the databinding be different?

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