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• Using Silverlight for Views in ASP.Net MVC - a bad idea?

  - by bplus

  I'm currently writing a small application for use internally at my office. I started out teaching myself some MVC (I've been a C# dev for 3 years). One of the main requirements is editable grids - I quickly realised that silverlight (i have zero silverlight experience) could be a big help in this. I've managed to create a proof of concept of getting MVC and silverlight to talk back an forth by combining these two techniques: Creating a Rest API using MVC MVC SilverLight I also got some help on stackoverflow: silverlight-grids-mvc-http-post Essentially all I'm doing is embedding a silver light object in a view. Serializing the Model data as JSON and passing it to silverlight(using intit params written into the response). The silverlight object can post data back to the controller as JSON. So far this seems like it could work quite well. However I am a bit concerned that I could be painting myself into a corner with this approach, as in I don't have much experience with either technology so I'm worried I'm going get hit with something further down the line that I won't be able to work around. Has anybody else tried doing this? Any advice would be much appreciated!

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• Yet another "What is this code doing"-type of Perl code

  - by Mike

  I have inherited some code from a guy whose favorite past time was to shorten every line to its absolute minimum (and sometimes only to make it look cool). His code is hard to understand but I managed to understand (and rewrite) most of it. Now I have stumbled on a piece of code which, no matter how hard I try, I cannot understand. my @heads = grep {s/\.txt$//} OSA::Fast::IO::Ls->ls($SysKey,'fo','osr/tiparlo',qr{^\d+\.txt$}) || (); my @selected_heads = (); for my $i (0..1) { $selected_heads[$i] = int rand scalar @heads; for my $j (0..@heads-1) { last if (!grep $j eq $_, @selected_heads[0..$i-1]); $selected_heads[$i] = ($selected_heads[$i] + 1) % @heads; #WTF? } my $head_nr = sprintf "%04d", $i; OSA::Fast::IO::Cp->cp($SysKey,'',"osr/tiparlo/$heads[$selected_heads[$i]].txt","$recdir/heads/$head_nr.txt"); OSA::Fast::IO::Cp->cp($SysKey,'',"osr/tiparlo/$heads[$selected_heads[$i]].cache","$recdir/heads/$head_nr.cache"); } From what I can understand, this is supposed to be some kind of randomizer, but I never saw a more complex way to achieve randomness. Or are my assumptions wrong? At least, that's what this code is supposed to do. Select 2 random files and copy them. === NOTES === The OSA Framework is a Framework of our own. They are named after their UNIX counterparts and do some basic testing so that the application does not need to bother with that.

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• How to estimate tomcat server requirements?

  - by Daniil

  We have a brand new webapp written that runs on Tomcat. So far, only one client is using it through the day. They run about 180 unique logins a day. Not really a lot IMO. Now, we managed to sell it to a brand new client who likes and wants to roll it out to 50,000 clients. How many of them will login at the same time - no idea. But I need to do the whole thing - allocate, create, config and maintain. OK - last is simple(errrr). The application runs off of Tomcat 5.5 on Gentoo (I'm thinking to upgrade to Tomcat 6) with MSSQL & mySQL behind. I do realize that a more enterprise ready application would be a better fit, but that's not an option at the moment. Since I've never done this before, I'm a bit lost. Can someone advice on how to go about estimating the equipment requirements for this client? Tomcat does have clustering, so that I can do. MS SQL - I'm sure they have something too. I'm thinking to stick it behind LVS (which we do use at the moment for something else too). Any help from people who deal with these details is greatly appreciated!

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• RSA_sign and RSACryptoProvider.VerifySignature

  - by Miky D

  I'm trying to get up to speed on how to get some code that uses OpenSSL for cryptography, to play nice with another program that I'm writing in C#, using the Microsoft cryptography providers available in .NET. More to the point, I'm trying to have the C# program verify an RSA message signature generated by the OpenSSL code. The code that generates the signature looks something like this: // Code in C, using the OpenSSL RSA implementation char msgToSign[] = "Hello World"; // the message to be signed char signature[RSA_size(rsa)]; // buffer that will hold signature int slen = 0; // will contain signature size // rsa is an OpenSSL RSA context, that's loaded with the public/private key pair memset(signature, 0, sizeof(signature)); RSA_sign(NID_sha1 , (unsigned char*)msgToSign , strlen(msgToSign) , signature , &slen , rsa); // now signature contains the message signature // and can be verified using the RSA_verify counterpart // .. I would like to verify the signature in C# In C#, I would do the following: import the other side's public key into an RSACryptoServiceProvider object receive the message and it's signature try to verify the signature I've got the first two parts working (I've verified that the public key is loading properly because I managed to send an RSA encrypted text from the C# code to the OpenSSL code in C and successfully have it decrypted) In order to verify the signature in C#, I've tried using the: VerifySignature method of the RSACryptoServiceProvider but that didn't work. And digging around the internet I was only able to find some vague information pointing out that .NET uses a different method for generating the signature than OpenSSL does. So, does anybody know how to accomplish this?

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• BinaryWriterWith7BitEncoding & BinaryReaderWith7BitEncoding

  - by Tim

  Mr. Ayende wrote in his latest blog post about an implementation of a queue. In the post he's using two magical files: BinaryWriterWith7BitEncoding & BinaryReaderWith7BitEncoding BinaryWriterWith7BitEncoding can write both int and long? using the following method signatures: void WriteBitEncodedNullableInt64(long? value) & void Write7BitEncodedInt(int value) and BinaryReaderWith7BitEncoding can read the values written using the following method signatures: long? ReadBitEncodedNullableInt64() and int Read7BitEncodedInt() So far I've only managed to find a way to read the 7BitEncodedInt: protected int Read7BitEncodedInt() { int value = 0; int byteval; int shift = 0; while(((byteval = ReadByte()) & 0x80) != 0) { value |= ((byteval & 0x7F) << shift); shift += 7; } return (value | (byteval << shift)); } I'm not too good with byte shifting - does anybody know how to read and write the 7BitEncoded long? and write the int ?

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• Reducing Time Complexity in Java

  - by Koeneuze

  Right, this is from an older exam which i'm using to prepare my own exam in january. We are given the following method: public static void Oorspronkelijk() { String bs = "Dit is een boodschap aan de wereld"; int max = -1; char let = '*'; for (int i=0;i<bs.length();i++) { int tel = 1; for (int j=i+1;j<bs.length();j++) { if (bs.charAt(j) == bs.charAt(i)) tel++; } if (tel > max) { max = tel; let = bs.charAt(i); } } System.out.println(max + " keer " + let); } The questions are: what is the output? - Since the code is just an algorithm to determine the most occuring character, the output is "6 keer " (6 times space) What is the time complexity of this code? Fairly sure it's O(n²), unless someone thinks otherwise? Can you reduce the time complexity, and if so, how? Well, you can. I've received some help already and managed to get the following code: public static void Nieuw() { String bs = "Dit is een boodschap aan de wereld"; HashMap<Character, Integer> letters = new HashMap<Character, Integer>(); char max = bs.charAt(0); for (int i=0;i<bs.length();i++) { char let = bs.charAt(i); if(!letters.containsKey(let)) { letters.put(let,0); } int tel = letters.get(let)+1; letters.put(let,tel); if(letters.get(max)<tel) { max = let; } } System.out.println(letters.get(max) + " keer " + max); } However, I'm uncertain of the time complexity of this new code: Is it O(n) because you only use one for-loop, or does the fact we require the use of the HashMap's get methods make it O(n log n) ? And if someone knows an even better way of reducing the time complexity, please do tell! :)

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• Excel Automation - creating a new worksheet

  - by Andrew Shepherd

  I am attempting what seems like a simple task: using C# to create a new Excel document containing new worksheets. For some reason, I am getting a strange COM error (0x800A03EC) Has anyone managed to get this to work? Does anyone have suggestions as to how to troubleshoot this? I've isolated this into the minimum amount of code: using Microsoft.Office.Interop.Excel; using System.Diagnostics; namespace ExcelAutomation { public static class ExcelTests { public static void CreateWorksheet() { try { var app = new Microsoft.Office.Interop.Excel.Application(); app.Visible = true; var workBooks = app.Workbooks; var newWorkbook = app.Workbooks.Add(XlWBATemplate.xlWBATWorksheet); Worksheet existingWorksheet = (Worksheet)newWorkbook.Sheets[1]; Worksheet workSheet = (Worksheet)newWorkbook.Sheets.Add ( null, // before existingWorksheet, null, // 1, null //XlSheetType.xlWorksheet ); } catch (System.Runtime.InteropServices.COMException ex) { Trace.WriteLine(string.Format("Caught COMException. Message: \"{0}\"", ex.Message)); } } } } The output window now says: Caught COMException. Message: "Exception from HRESULT: 0x800A03EC"

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• how to read an arraylist from a txt file in java?

  - by lox

  how to read an arraylist from a txt file in java? my arraylist is the form of: public class Account { String username; String password; } i managed to put some "Accounts" in the a txt file, but now i don't know how to read them. this is how my arraylist look in the txt file: username1 password1 | username2 password2 | etc this is a part of the code i came up with, but it doesn't work. it looks logic to me though... :) . public static void RdAc(String args[]) { ArrayList<Account> peoplelist = new ArrayList<Account>(50); int i,i2,i3; String[] theword = null; try { FileReader fr = new FileReader("myfile.txt"); BufferedReader br = new BufferedReader(fr); String line = ""; while ((line = br.readLine()) != null) { String[] theline = line.split(" | "); for (i = 0; i < theline.length; i++) { theword = theline[i].split(" "); } for(i3=0;i3<theline.length;i3++) { Account people = new Account(); for (i2 = 0; i2 < theword.length; i2++) { people.username = theword[i2]; people.password = theword[i2+1]; peoplelist.add(people); } } } } catch (IOException ex) { System.out.println("Could not read from file"); } }

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• How to best configure a central repository/multiple central repositories for Mercurial?

  - by Mario

  I am new to Mercurial and trying to figure out if it could replace SVN. Everyone I work with has used SVN, CVS and VSS (shiver), so this could be quite a large change. I have been very interested after reading about its merge and branch capability, but have a few reservations. We are currently on SVN, and have one central repository. From my reading, it seems as though there is no ONE central repository for all projects when using Mercurial. NOTE: We consider each project a separate logical set of code, or a Visual Studio Solution. It runs on its own. We have around 60 separate projects in our one central SVN repository. After reading about Mercurial it seems to me that I have to create 60 separate central repositories for each one of these projects on the server. QUESTION #1: Should I create a single repository for each project? If yes, then I am worried about configuring and hosting 60 separate central Mercurial servers. I started thinking I could configure one file, but it seems as if each repository must be individually configured using the “C:...\MyRepository.hg\hgrc” file (Windows install). It also seems as I have to run 60 servers (hg serve), I would assume on different ports. QUESTION #2: If the answer to question 1 is yes, there should be a single central repository for each project, then how have people managed many multiple repositories? Finally, I haven’t looked into moving all history and changes from one SVN repository to a bunch of separate Mercurial repositories, but would appreciate any comments from someone who has done this (or if it is even possible).

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• java applet stops running on exceptions

  - by Marius

  I've developed a simple applet that imports an image from the clipboard. When i run the class file from NetBeans, everything works fine. But when i try to run it as an applet ... it gives me lots of errors in the java console and does not run ... - The applet is signed - There is a static method in one class, called getImageFromClipboard(). When the applet runs, it calls this method. - getImageFromClipboard() method has a try-catch block and suppresses all errors. It simply returns either a BufferedImage or null. - When applet runs, it does some visual adjustments before calling getImageFromClipboard() Now the scenario is as follows: the class from netbeans runs, fails to import the image and adjusts the interface accordingly (displays an error in a label) But when i run it in a browser, java console is filled with errors and nothing after the getImageFromClipboard() line works. Although the applet itself loads and does everything it's supposed do do before importing the image. So why am i getting errors if i accept the certificate and all of the possible errors are in try-catch blocks? None of this code should throw any exceptions. Any ideas why this is happening? Or do you need to see the errors to tell? UPDATE I've managed to find out the problem myself. The class that i'm using is not in the jar file :( How do i add it in? I'm using "add jar folder" in netbeans on the libraries package to import it but it does not seem to get copied to the jar.

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• Core Data, Bindings, value transformers : crash when saving

  - by Gael

  Hi, I am trying to store a PNG image in a core data store backed by an sqlite database. Since I intend to use this database on an iPhone I can't store NSImage objects directly. I wanted to use bindings and an NSValueTransformer subclass to handle the transcoding from the NSImage (obtained by an Image well on my GUI) to an NSData containing the PNG binary representation of the image. I wrote the following code for the ValueTransformer : + (Class)transformedValueClass { return [NSImage class]; } + (BOOL)allowsReverseTransformation { return YES; } - (id)transformedValue:(id)value { if (value == nil) return nil; return [[[NSImage alloc] initWithData:value] autorelease]; } - (id)reverseTransformedValue:(id)value { if (value == nil) return nil; if(![value isKindOfClass:[NSImage class]]) { NSLog(@"Type mismatch. Expecting NSImage"); } NSBitmapImageRep *bits = [[value representations] objectAtIndex: 0]; NSData *data = [bits representationUsingType:NSPNGFileType properties:nil]; return data; } The model has a transformable property configured with this NSValueTransformer. In Interface Builder a table column and an image well are both bound to this property and both have the proper value transformer name (an image dropped in the image well shows up in the table column). The transformer is registered and called every time an image is added or a row is reloaded (checked with NSLog() calls). The problem arises when I am trying to save the managed objects. The console output shows the error message : [NSImage length]: unrecognized selector sent to instance 0x1004933a0 It seems like core data is using the value transformer to obtain the NSImage back from the NSData and then tries to save the NSImage instead of the NSData. There are probably workarounds such as the one presented in this post but I would really like to understand why my approach is flawn. Thanks in advance for your ideas and explanations.

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• Transfer data between C++ classes efficiently

  - by David

  Hi, Need help... I have 3 classes, Manager which holds 2 pointers. One to class A another to class B . A does not know about B and vise versa. A does some calculations and at the end it puts 3 floats into the clipboard. Next, B pulls from clipboard the 3 floats, and does it's own calculations. This loop is managed by the Manager and repeats many times (iteration after iteration). My problem: Now class A produces a vector of floats which class B needs. This vector can have more than 1000 values and I don't want to use the clipboard to transfer it to B as it will become time consumer, even bottleneck, since this behavior repeats step by step. Simple solution is that B will know A (set a pointer to A). Other one is to transfer a pointer to the vector via Manager But I'm looking for something different, more object oriented that won't break the existent separation between A and B Any ideas ? Many thanks David

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• does sfWidgetFormSelect provide a string or an int of the selected item?

  - by han

  Hey guys, I'm having an annoying problem. I'm trying to find out what fields of a form were changed, and then insert that into a table. I managed to var_dump in doUpdateObjectas shown in the following public function doUpdateObject($values) { parent::doUpdateObject($values); var_dump($this->getObject()->getModified(false)); var_dump($this->getObject()->getModified(true)); } And it seems like $this-getObject()-getModified seems to work in giving me both before and after values by setting it to either true or false. The problem that I'm facing right now is that, some how, sfWidgetFormSelect seems to be saving one of my fields as a string. before saving, that exact same field was an int. (I got this idea by var_dump both before and after). Here is what the results on both var dumps showed: array(1) {["annoying_field"]=> int(3)} array(1) {["annoying_field"]=>string(1)"3"} This seems to cause doctrine to think that this is a modification and thus gives a false positive. In my base form, I have under $this->getWidgets() 'annoying_field' => new sfWidgetFormInputText(), under $this->setValidators 'annoying_field' => new sfValidatorInteger(array('required' => false)), and lastly in my configured Form.class.php I have reconfigured the file as such: $this->widgetSchema['annoying_field'] = new sfWidgetFormSelect(array('choices' => $statuses)); statuses is an array containing values like {""a", "b", "c", "d"} and I just want the index of the status to be stored in the database. And also how can I insert the changes into another database table? let's say my Log table? Any ideas and advice as to why this is happen is appreciated, I've been trying to figure it out and browsing google for various keywords with no avail. Thanks! Edit: ok so I created another field, integer in my schema just for testing. I created an entry, saved it, and edited it. this time the same thing happened!

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• Prevent "hg status" from showing everything under untracked directories

  - by Wei Hu

  I find the output of hg status too verbose for untracked directories. Suppose I have an empty repository that's managed by both git and hg. So there would be two directories, .git and .hg. The output of git status is: # Untracked files: # (use "git add <file>..." to include in what will be committed) # # .hg/ The output of hg status is: ? .git/HEAD ? .git/config ? .git/description ? .git/hooks/applypatch-msg.sample ? .git/hooks/commit-msg.sample ? .git/hooks/post-commit.sample ? .git/hooks/post-receive.sample ? .git/hooks/post-update.sample ? .git/hooks/pre-applypatch.sample ? .git/hooks/pre-commit.sample ? .git/hooks/pre-rebase.sample ? .git/hooks/prepare-commit-msg.sample ? .git/hooks/update.sample ? .git/info/exclude Is there a way to reduce its output to something like the following line? ? .git/

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• Delete specific files after installation using visual studio setup project

  - by Vadiklk

  I have this problem. I want to build an installer for my c# solution, that will be placed in a folder with other installation folders and files that are needed to be copied to the installed folder. So that is easy, I just copy them to the folder I create using the folder structure I want. Now, I want also to install another program and run a .exe file I've created to unzip some files for me. For that I need to copy 2 .exe files and 2 dlls (for the exes) to the folder to which I am installing and create 2 custom actions that will use them. That I've managed to do. After that I want to delete those 4 extra files, as the user does not need them and shouldn't even be aware they are there. How to do so? I couldn't find a way in the built in setup project preferences + I do not know how to make a custom installer class. A bonus question, is how to make the other installer (one of the .exe files is just a plain installer) install quietly to any path? I do not want the user to see an installer pop out of my program installer. Thanks!

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• Cannot get new product attribute in grid display

  - by russjman

  I added a new attribute to my products(a boolean "yes/no" field). It is a variable to enable/disable the price from displaying on the product detail page, and grid view. I managed to get it work on the product info page. But on product grid page I cant seem to access that variable. Specifically, the template i am working with is catalog/product/price.phtml. From what i can tell, the price is being displayed by the same group of if-statements on both the product detail page, and grid page. This has me confused because i cant find any code on that template to handle multiple products, just a bunch of nested if statements. this is how im attempting to access this new variable using $_displayPrice. on line 36 of catalog/product/price.html <?php $_product = $this->getProduct(); ?> <?php $_id = $_product->getId() ?> <?php $_displayPrice = $_product->getDisplayPrice() ? "Yes" : "No"; echo $_displayPrice;?> What has me further confused is that when display $_product-getData(), my new variable isn't anywhere among that data. thanks in advance

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• Web Deployment Project failed to map path for include virtual

  - by Duke

  I am building my site with a web deployment project but the build fails with a number of errors all relating to the "#include virtual" directives in my master page. The includes are necessary to import a set of centrally managed html template files. Here is an example of the include directive and associated error: <!-- #include virtual="/v3/sits/pdpdev/assets-templates/inc/head.html" --> /PDPRegistration.csproj/Pages/ContentPage.Master(15): error ASPPARSE: Failed to map the path '/v3/sits/pdpdev/assets-templates/inc/head.html'. The error for each included file actually appears multiple times. I'm not sure what is being mapped or why, but this was never a problem until I started using WDP (which I wanted to alter web.config depending on the build environment, among other things.) The project is built locally on my PC and then copied to the web server via a mapped drive. I found a few solutions on the 'net involving IIS metabase - they weren't quite clear to me, and I'm not sure if they apply given how I build and deploy the project (that is, would I have to build on the same system as IIS in order to make use of the metabase?) Can anyone suggest how I can get my project to build with WDP?

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• Please help us non-C++ developers understand what RAII is

  - by Charlie Flowers

  Another question I thought for sure would have been asked before, but I don't see it in the "Related Questions" list. Could you C++ developers please give us a good description of what RAII is, why it is important, and whether or not it might have any relevance to other languages? I do know a little bit. I believe it stands for "Resource Acquisition is Initialization". However, that name doesn't jive with my (possibly incorrect) understanding of what RAII is: I get the impression that RAII is a way of initializing objects on the stack such that, when those variables go out of scope, the destructors will automatically be called causing the resources to be cleaned up. So why isn't that called "using the stack to trigger cleanup" (UTSTTC:)? How do you get from there to "RAII"? And how can you make something on the stack that will cause the cleanup of something that lives on the heap? Also, are there cases where you can't use RAII? Do you ever find yourself wishing for garbage collection? At least a garbage collector you could use for some objects while letting others be managed? Thanks.

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• Is there a tool I can use to generate interfaces and wrappers for object mocking in c#

  - by fostandy

  Given a class like System.Timers.Timer, or ANY managed class (whether user defined, from the .net framework, or some 3rd party library) is there some program I can use to (a) generate an interface based on this class and (b) generate a wrapper for the given class? for example if I have a public class Foo { public object MyProperty { get { ... } set { ... } } public int SomeMethod(object a) { ... } } it will create an interface interface IFoo { object MyProperty { get; set; } int SomeMethod(object a) { ... } } and maybe even a wrapper class FooWrap { // something for relay constructor here ... Foo _me; public object MyProperty { get { return _me.MyProperty; } set { _me.MyProperty = value; } } public int SomeMethod(object a) { return _me.SomeMethod(); } } Obviously there's stuff I haven't thought about like events, generics etc. I want a DWIMNWIS-PSICHTO(-Plus-Stuff-I-Clearly-Haven't-Thought-Of). I'm aware resharper can be used to extract an interface but I've only been able to use this on my own classes. Aside: Wow, it is amazing how simply becoming accustomed to a previously 'unacceptable' idea eventually gives it legitimacy. A year ago the idea of having to create interfaces for all objects I want to mock and adopting an injection framework would have seemed like the height of madness. It turns out that while it's not quite death and taxes, it is sparta. I am aware of and have used typemock. It certainly is the work of elvish wizards. One day when $800 does not seem like quite so much money I intend to buy it.

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• Removing elements using XSLT 1.0

  - by pmdarrow

  I'm attempting to remove Component elements from the XML below that have File children with the extension "config." I've managed to do this part, but I also need to remove the matching ComponentRef elements that have the same IDs as these Components. <Fragment> <DirectoryRef Id="MyWebsite"> <Component Id="Comp1"> <File Source="Web.config" /> </Component> <Component Id="Comp2"> <File Source="Default.aspx" /> </Component> </DirectoryRef> </Fragment> <Fragment> <ComponentGroup Id="MyWebsite"> <ComponentRef Id="Comp1" /> <ComponentRef Id="Comp2" /> </ComponentGroup> </Fragment> Based on other SO answers, I've come up with the following XSLT to remove these Component elements: <?xml version="1.0" encoding="utf-8"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output method="xml" indent="yes" /> <xsl:template match="Component[File[substring(@Source, string-length(@Source)- string-length('config') + 1) = 'config']]" /> <xsl:template match="@*|node()"> <xsl:copy> <xsl:apply-templates select="@*|node()"/> </xsl:copy> </xsl:template> </xsl:stylesheet> Unfortunately, this doesn't remove the matching ComponentRef elements. The XSLT will remove the component with the Id "Comp1" but not the ComponentRef with Id "Comp1". How do I achieve this using XSLT 1.0?

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• Handle row deletion in UITableViewController

  - by Kamchatka

  Hello, I hava a UINavigationController. The first level is a UITableViewController, the second level just shows details on one of the items of the table view. In this detail view, I can delete the item. It deletes the underlying managed object. When I pop back to the view, I have a crash. I understand why, it's because I didn't update the cached array that contains the data. I looked at several tutorials and I don't exactly understand how am I supposed to handle deletion. Maybe I don't understand exactly where I should fetch the objects in the model. Should I do a query for every cellForRowAtIndexPath and take the item in the result at position indexPath.row? It doesn't look efficient. Should I check for changes somewhere and recache the whole query in an array. I would think CoreData would provide something more natural but I couldn't find it so far. Thanks in advance.

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• Systems design question: DB connection management in load-balanced n-tier

  - by aoven

  I'm wondering about the best approach to designing a DB connection manager for a load-balanced n-tier system. Classic n-tier looks like this: Client -> BusinessServer -> DBServer A load-balancing solution as I see it would then look like this: +--> ... +--+ +--> BusinessServer +--+--> SessionServer --+ Client -> Gateway --+--> BusinessServer +--| +--> DBServer +--> BusinessServer +--+--------------------+ +--> ... +--+ As pictured, the business server component is being load-balanced via multiple instances, and a hardware gateway is distributing the load among them. Session server probably needs to be situated outside the load-balancing array, because it manages state, which mustn't be duplicated. Barring any major errors in design so far, what is the best way to implement DB connection management? I've come up with a couple of options, but there may be others I'm not aware of: Introduce a new Broker component between the DBServer and the other components and let it handle the DB connections. The upside is that all the connections can be managed from a single point, which is very convenient. The downside is that now there is an additional "single point of failure" in the system. Other components must go through it for every request that involves DB in some way, which also makes this a bottleneck. Move the DB connection management into BusinessServer and SessionServer components and let each handle its own DB connections. The upside is that there is no additional "single point of failure" or bottleneck components. The downside is that there is also no control over possible conflicts and deadlocks apart from what DBServer itself can provide. What else can be done? FWIW: Technology is .NET, but none of the vendor-specific stacks are used (e.g. no WCF, MSMQ or the like).

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• Using Reflection.Emit to emit a "using (x) { ... }" block?

  - by Lasse V. Karlsen

  I'm trying to use Reflection.Emit in C# to emit a using (x) { ... } block. At the point I am in code, I need to take the current top of the stack, which is an object that implements IDisposable, store this away in a local variable, implement a using block on that variable, and then inside it add some more code (I can deal with that last part.) Here's a sample C# piece of code I tried to compile and look at in Reflector: public void Test() { TestDisposable disposable = new TestDisposable(); using (disposable) { throw new Exception("Test"); } } This looks like this in Reflector: .method public hidebysig instance void Test() cil managed { .maxstack 2 .locals init ( [0] class LVK.Reflection.Tests.UsingConstructTests/TestDisposable disposable, [1] class LVK.Reflection.Tests.UsingConstructTests/TestDisposable CS$3$0000, [2] bool CS$4$0001) L_0000: nop L_0001: newobj instance void LVK.Reflection.Tests.UsingConstructTests/TestDisposable::.ctor() L_0006: stloc.0 L_0007: ldloc.0 L_0008: stloc.1 L_0009: nop L_000a: ldstr "Test" L_000f: newobj instance void [mscorlib]System.Exception::.ctor(string) L_0014: throw L_0015: ldloc.1 L_0016: ldnull L_0017: ceq L_0019: stloc.2 L_001a: ldloc.2 L_001b: brtrue.s L_0024 L_001d: ldloc.1 L_001e: callvirt instance void [mscorlib]System.IDisposable::Dispose() L_0023: nop L_0024: endfinally .try L_0009 to L_0015 finally handler L_0015 to L_0025 } I have no idea how to deal with that ".try ..." part at the end there when using Reflection.Emit. Can someone point me in the right direction?

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• I trying to backreference using the sed command

  - by Paul

  I am relative new to shell scripting and sed. I need to substitute a pattern, globably, but I also need to remember (or save) part of the pattern and use it later in the same substitute command. The saved pattern will be varible, so I need to use a wild card. For example, input message=trt:GetAudioSourcesRequest/> and I want to end up with something like input message=trt:GetAudioSourcesRequest PAUL/GetAudioSourcesRequest/> but the function string "GetAudioSourcesRequest" will change (in length also) throughtout the file, so I need a wild card, e.g. sed -i "s/input message=trt:<wild card in here>/>/input message=trt:<print wild card> PAUL/<print wild card>/> I have managed to get the following command to nearly do what I want but it is too rigid. It only stores a 4 syllable pattern so if I have a function name such as GetProfileRequest, this doesn't work echo "input message=\"trt:GetAudioSourcesRequest\"/>" | sed 's/input message=\"trt:\([A-Z][a-z]*\)\([A-Z][a-z]*\)\([A-Z][a-z]*\)\([A-Z][a-z]*\).*/input message=\"trt:\1\2\3\4\ PAUL\/\1\2\3\4"\/\>/g' This outputs input message="trt:GetAudioSourcesRequest PAUL/GetAudioSourcesRequest"/> Which is ok but when I use GetProfileRequest this doesn't. I have come accross \W and [^[:alnum:]] or [[:alnum:]] but I don't how to use them Thanks in advance.

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• Cutting Ubuntu to the bone for Virtualbox VM

  - by Monty

  I've been looking around for a Linux variant which will install only the software I need rather than everything Ubuntu (for example) puts in by default. This is to create a virtual machine in Virtualbox which has bash, apache, python, perl, SQLite, openssh and a few other programs but nothing else. I'd prefer to go with Ubuntu if possible but another modern distro would do as well (I like using apt-get and yum rather than downloading/compiling etc). So far, I've tried: SuseStudio.com, which is probably the best so far. Pressing F4 to get the boot options on Ubuntu 9.10, but there is no minimal installation (I think there was once). Arch Linux, slightly confusing install procedure but I might go back and try again. Gentoo, started well but fairly soon the HD on the virtual machine went to 2Gb, even before the installation had started in earnest (I'd partitioned the disks is all). I realise there are various "small" Linuxes around like Puppy, Feather, DSL, etc, but they seem to be aimed at desktop users or as a techie's toolkit, and I want a small-as-possible server distro which can be managed with tools like apt or yum or similar. TIA for any advice you can offer! -- Monty

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