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• Correct use of Classloader (especially in Android)

  - by Sebi

  I read some documentations about classloaders, but im still not sure where and why they are needed. The Android API says: Loads classes and resources from a repository. One or more class loaders are installed at runtime. These are consulted whenever the runtime system needs a specific class that is not yet available in-memory. So if i understand this correct, there can be many classlaoders which are responsible for loading new classes. But how the system decides which to use? And in which situation should a developer instantiate a new classloader? In the Android API for Intent there is a method public void setExtrasClassLoader (ClassLoader loader) The description says: Sets the ClassLoader that will be used when unmarshalling any Parcelable values from the extras of this Intent. So can i define there a special classloader so that i can pass object with an Intent which are not defined in the receiving activity? An example: If activity A which is located in Project A (in Eclipse) defines an object which i want to send to Activity B in Project B using putExtra of the Intent object. If this object which is send over the Intent is not defined (source code in project B), then there is a NoClassDefFoundException. So can i use the method setExtraClassloader to avoid this exception? If yes, how can i decide which classloader object i have to pass? And how do I instantiate it correctly?

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• php parsing speed optimization

  - by Arnaud

  I would like to add tooltip or generate link according to the element available in the database, for exemple if the html page printed is: to reboot your linux host in single-user mode you can ... I will use explode(" ", $row[page]) and the idea is now to lookup for every single word in the page to find out if they have a related referance in this exemple let's say i've got a table referance an one entry for reboot and one for linux reboot: restart a computeur linux: operating system now my output will look like (replaced < and by @) to @a href="ref/reboot"@reboot@/a@ your @a href="ref/linux"@linux@/a@ host in single-user mode you can ... Instead of have a static list generated when I saved the content, if I add more keyword in the future, then the text will become more interactive. My main concerne and question is how can I create a efficient enough process to do it ? Should I store all the db entry in an array and compare them ? Do an sql query for each word (seems to be crazy) Dump the table in a file and use a very long regex or a "grep -f pattern data" way of doing it? Or or or or I'm sure it must be a better way of doing it, just don't have a clue about it, or maybe this will be far too resource un-friendly and I should avoid doing such things. Cheers!

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• How to easily substitute a Base class

  - by JTom

  Hi, I have the following hierarchy of classes class classOne { virtual void abstractMethod() = 0; }; class classTwo : public classOne { }; class classThree : public classTwo { }; All classOne, classTwo and classThree are abstract classes, and I have another class that is defining the pure virtual methods class classNonAbstract : public classThree { void abstractMethod(); // Couple of new methods void doIt(); void doItToo(); }; And right now I need it differently...I need it like class classNonAbstractOne : public classOne { void abstractMethod(); // Couple of new methods void doIt(); void doItToo(); }; class classNonAbstractTwo : public classTwo { void abstractMethod(); // Couple of new methods void doIt(); void doItToo(); }; and class classNonAbstractThree : public classThree { void abstractMethod(); // Couple of new methods void doIt(); void doItToo(); }; But all the nonAbstract classes have the same new methods, with the same code...and I would like to avoid copying all the methods and it's code to every nonAbstract class. How could I accomplish that? Hopefully it's understandable...

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• How to cache pages using background jobs ?

  - by Alexandre

  Definitions: resource = collection of database records, regeneration = processing these records and outputting the corresponding html Current flow: Receive client request Check for resource in cache If not in cache or cache expired, regenerate Return result The problem is that the regeneration step can tie up a single server process for 10-15 seconds. If a couple of users request the same resource, that could result in a couple of processes regenerating the exact same resource simultaneously, each taking up 10-15 seconds. Wouldn't it be preferrable to have the frontend signal some background process saying "Hey, regenerate this resource for me". But then what would it display to the user? "Rebuilding" is not acceptable. All resources would have to be in cache ahead of time. This could be a problem as the database would almost be duplicated on the filesystem (too big to fit in memory). Is there a way to avoid this? Not ideal, but it seems like the only way out. But then there's one more problem. How to keep the same two processes from requesting the regeneration of a resource at the same time? The background process could be regenerating the resource when a frontend asks for the regeneration of the same resource. I'm using PHP and the Zend Framework just in case someone wants to offer a platform-specific solution. Not that it matters though - I think this problem applies to any language/framework. Thanks!

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• How can I prevent default_environment variables from getting set by Capistrano's sudo action?

  - by Logan Koester

  My deploy.rb sets some environment variables to use the regular user's local Ruby rather than the system-wide one. set :default_environment, { :PATH => '/home/myapp/.rvm/bin:/home/myapp/.rvm/bin:/home/myapp/.rvm/rubies/ruby-1.9.1-p378/bin:/home/myapp/.rvm/gems/ruby-1.9.1-p378/bin:/home/myapp/.rvm/gems/ruby-1.9.1-p378%global/bin:/home/myapp/bin:/usr/bin:/opt/local/bin:/opt/local/sbin:/usr/local/bin:/usr/local/sbin:/usr/sbin:/sbin:/bin:/usr/games', :RUBY_VERSION => 'ruby-1.9.1-p378', :GEM_HOME => '/home/myapp/.rvm/gems/ruby-1.9.1-p378', :GEM_PATH => '/home/myapp/.rvm/gems/ruby-1.9.1-p378:/home/myapp/.rvm/gems/ruby-1.9.1-p378%global' } Naturally, when a task is using sudo, I would expect the system-wide ruby to be used instead. But it seems the environment variables are being set anyway, which is obviously invalid for the root user and returns an error: executing "sudo -p 'sudo password: ' /etc/init.d/god stop" servers: ["myapp.com"] [myapp.com] executing command command finished failed: "env PATH=/home/myapp/.rvm/bin:/home/myapp/.rvm/bin:/home/myapp/.rvm/rubies/ruby-1.9.1-p378/bin:/home/myapp/.rvm/gems/ruby-1.9.1-p378/bin:/home/myapp/.rvm/gems/ruby-1.9.1-p378%global/bin:/home/myapp/bin:/usr/bin:/opt/local/bin:/opt/local/sbin:/usr/local/bin:/usr/local/sbin:/usr/sbin:/sbin:/bin:/usr/games RUBY_VERSION=ruby-1.9.1-p378 GEM_HOME=/home/myapp/.rvm/gems/ruby-1.9.1-p378 GEM_PATH=/home/myapp/.rvm/gems/ruby-1.9.1-p378:/home/myapp/.rvm/gems/ruby-1.9.1-p378%global sh -c 'sudo -p '\\''sudo password: '\\'' /etc/init.d/god stop'" on myapp.com It makes no difference whether I use capistrano's sudo "system call" or the regular run "sudo system call". How can I avoid this?

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• how do call a polymorphic function from an agnostic function?

  - by sds

  I have a method foo void foo (String x) { ... } void foo (Integer x) { ... } and I want to call it from a method which does not care about the argument: void bar (Iterable i) { ... for (Object x : i) foo(x); // this is the only time i is used ... } the code above complains that that foo(Object) is not defined and when I add void foo (Object x) { throw new Exception; } then bar(Iterable<String>) calls that instead of foo(String) and throws the exception. How do I avoid having two textually identical definitions of bar(Iterable<String>) and bar(Iterable<Integer>)? I thought I would be able to get away with something like <T> void bar (Iterable<T> i) { ... for (T x : i) foo(x); // this is the only time i is used ... } but then I get cannot find foo(T) error.

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• What is the best URL strategy to handle multiple search parameters and operators?

  - by Jon Winstanley

  Searching with mutltiple Parameters In my app I would like to allow the user to do complex searches based on several parameters, using a simple syntax similar to the GMail functionality when a user can search for "in:inbox is:unread" etc. However, GMail does a POST with this information and I would like the form to be a GET so that the information is in the URL of the search results page. Therefore I need the parameters to be formatted in the URL. Requirements: Keep the URL as clean as possible Avoid the use of invalid URL chars such as square brackets Allow lots of search functionality Have the ability to add more functions later. I know StackOverflow allows the user to search by multiple tags in this way: http://stackoverflow.com/questions/tagged/c+sql However, I'd like to also allow users to search with multiple additional parameters. Initial Design My design is currently to do use URLs such as these: http://example.com/search/tagged/c+sql/searchterm/transactions http://example.com/search/searchterm/transactions http://example.com/search/tagged/c+sql http://example.com/search/tagged/c+sql/not-tagged/java http://example.com/search/tagged/c+sql/created/yesterday http://example.com/search/created_by/user1234 I intend to parse the URL after the search parameter, then decide how to construct my search query. Has anyone seen URL parameters like this implemented well on a website? If so, which do it best?

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• Turning off antialiasing in Löve2D

  - by cjanssen

  I'm using Löve2D for writing a small game. Löve2D is an open source game engine for Lua. The problem I'm encountering is that some antialias filter is automatically applied to your sprites when you draw it at non-integer positions. love.graphics.draw( sprite, x, y ) So when x or y is not round (for example, x=100.24), the sprite appears blurred. The same happens when the sprite size is not even, because (x,y) points to the center of the sprite. For example, a sprite which is 31x30 big will appear blurred again, because its pixels are painted in non-integer positions. Since I am using pixel art, I want to avoid this all the way, otherwise the art is destroyed by this effect. The workaround I am using so far is to force the coordinates to be round by littering the code with calls to math.floor(), and forcing all the sprites to have even sizes by adding a row or column of transparent pixels with the paint program, if needed. Is there some command to deactivate the antialiasing I can call at program startup?

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• IndexOutofRangeException while using WriteLine in nested Parallel.For loops

  - by Umar Asif

  I am trying to write kinect depth data to a text file using nested Parallel.For loops with the following code. However, it gives IndexOutofRangeException. The code works perfect if using simple for loops but it hangs the UI since the depth format is set to 640x480 causing the loops to write 307200 lines in the text file at 30fps. Therefore, I switched to Parallel. For scheme. If I omit the writeLine command from the nested loops, the code works fine, which indicates that the IndexOutofRangeException is arising at the writeline command. I do not know how to troubleshoot this. Please advise. Any better workarounds to avoid UI freezing? Thanks. using (DepthImageFrame depthImageframe = d.OpenDepthImageFrame()) { if (depthImageframe == null) return; depthImageframe.CopyPixelDataTo(depthPixelData); swDepth = new StreamWriter(@"E:\depthData.txt", false); int i = 0; Parallel.For(0, depthImageframe.Width, delegate(int x) { Parallel.For(0, depthImageframe.Height, delegate(int y) { p[i] = sensor.MapDepthToSkeletonPoint(depthImageframe.Format, x, y, depthPixelData[x + depthImageframe.Width * y]); swDepth.WriteLine(i + "," + p[k].X + "," + p[k].Y + "," + p[k].Z); i++; }); }); swDepth.Close(); } }

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• SVN checkout or export for production environment?

  - by Eran Galperin

  In a project I am working on, we have an ongoing discussion amongst the dev team - should the production environment be deployed as a checkout from the SVN repository or as an export? The development environment is obviously a checkout, since it is constantly updated. For the production, I'm personally for checking out the main trunk, since it makes future updates easier (just run svn update). However some of the devs are against it, as svn creates files with the group/owner and permissions of the svn process (this is on a linux OS, so those things matter), and also having the .svn directories on the production seem to them to be somewhat dirty. Also, if it is a checkout - how do you push individual features to the production without including in-development code? do you use tags or branch out for each feature? any alternatives? EDIT: I might not have been clear - one of the requirement is to be able to constantly be able to push fixes to the production environment. We want to avoid a complete build (which takes much longer than a simple update) just for pushing critical fixes.

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• How to use Data aware controls "correctly"?

  - by lyborko

  Hi, I would like to ask experienced users, if you prefer to use data aware controls to add, insert, delete and edit data in DB or you favor to do it manualy. I developed some DB applications, in which for the sake of "user friendly policy" I run into complicated web of table events (afterinsert, afteredit, after... and beforeedit, beforeinsert, before...). After that it was a quite nasty work to debug the application. Aware of this risk (later by another application) I tried to avoid this problem, so I paid increased attention to write code well, readable and comprehensive. It seemed everything all right from the beginning, but as I needed to handle some preprocessing stuff before sending and loading data etc, I run into the same problems again, "slowly and inevitably". Sometime I could not use dataaware controls anyway, and what seemed to be a "cool" feature of DAControl at the beginning it turned to an obstacle on the end. I "had to" write special routine for non-dataaware controls, in order to behave as dataaware. Then I asked myself, why on earth should I use dataaware controls? Is it better to found application architecture on non-dataaware controls? It requires more time to write bug-proof code, of course, but does it worth of it? I do not know... I happened to me several times, like jinxed : paradise on the beginning hell on the end... I do not know, if I use wrong method to write DB program, if there is some standard common practice how to proceed. Or if it is common problem to everybody? Thanx for advices and your experiences

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• How to Elegantly convert switch+enum with polymorphism

  - by Kyle

  I'm trying to replace simple enums with type classes.. that is, one class derived from a base for each type. So for example instead of: enum E_BASE { EB_ALPHA, EB_BRAVO }; E_BASE message = someMessage(); switch (message) { case EB_ALPHA: applyAlpha(); case EB_BRAVO: applyBravo(); } I want to do this: Base* message = someMessage(); message->apply(this); // use polymorphism to determine what function to call. I have seen many ways to do this which all seem less elegant even then the basic switch statement. Using dyanimc_pointer_cast, inheriting from a messageHandler class that needs to be updated every time a new message is added, using a container of function pointers, all seem to defeat the purpose of making code easier to maintain by replacing switches with polymorphism. This is as close as I can get: (I use templates to avoid inheriting from an all-knowing handler interface) class Base { public: template<typename T> virtual void apply(T* sandbox) = 0; }; class Alpha : public Base { public: template<typename T> virtual void apply(T* sandbox) { sandbox->applyAlpha(); } }; class Bravo : public Base { public: template<typename T> virtual void apply(T* sandbox) { sandbox->applyBravo(); } }; class Sandbox { public: void run() { Base* alpha = new Alpha; Base* bravo = new Bravo; alpha->apply(this); bravo->apply(this); delete alpha; delete bravo; } void applyAlpha() { // cout << "Applying alpha\n"; } void applyBravo() { // cout << "Applying bravo\n"; } }; Obviously, this doesn't compile but I'm hoping it gets my problem accross.

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• Fitting title for my position

  - by lithander

  In the last 2 years my company has developed a boxed and full-price computer game. All the software development has been done collaboratively by me and my co-developer. We know each other from university and got hired at the same day to equal conditions and we share the same responsibilites including the decisions of what technology to license and how to spend development resources and even how team-workflow is organized. But I struggle to find the correct wording for my position. Can I call myself a senior developer with only 3 years working-experience? Can I call myself lead programmer if I don't really have a team to "lead"? All these fancy names used in the industry (Technical Lead, Development Lead, Software Architect) seem to imply that you aren't actually coding anymore or have staff under you. On the other hand titles like "Programmer" or "Software Engineer" seem to imply that there's someone between you and the project management. That makes it hard to fill out a resume or even the badges you typically wear on conferences... people tend to judge you by your title and I'd like to avoid confusion where possible.

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• Reducing moire when downsampling halftone comic images.

  - by drawnonward

  How can I reduce moire effects when downsampling halftone comic book images during live zoom on an iPhone or iPad? I am writing a comic book viewer. It would be nice to provide higher resolution images and allow the user to zoom in while reading the comic book. However, my client is averse to moire effects and will not allow this feature if there are noticeable moire artifacts while zooming, which of course there are. Modifying the images to be less susceptible to moire would only work if the modifications were not perceptible. Blur was specifically prohibited, as is anything that removes the beloved halftone dots. The images are black and white halftone and line art. The originals are 600 dpi but what we ship with the application will be half that at best, so probably 2500 pixels or less tall. So what are my options? If I write a custom downsampling algorithm would it be fast enough for real time on these devices? Are there other tricks I can do? Would it work to just avoid the size ratios that have the most visual moire effects? As you zoom in an out, there are definitely peaks where the moire effects are worst. Is there a way to calculate what those points are and just zoom to a nearby scale that is not as bad? Any suggestions are welcome. I have very little experience with image and signal processing, but am enjoying the opportunity to learn. I know nothing of wavelets and acutance and other jargon, so please be verbose.

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• Avoiding secondary selects or joins with Hibernate Criteria or HQL query

  - by Ben Benson

  I am having trouble optimizing Hibernate queries to avoid performing joins or secondary selects. When a Hibernate query is performed (criteria or hql), such as the following: return getSession().createQuery(("from GiftCard as card where card.recipientNotificationRequested=1").list(); ... and the where clause examines properties that do not require any joins with other tables... but Hibernate still performs a full join with other tables (or secondary selects depending on how I set the fetchMode). The object in question (GiftCard) has a couple ManyToOne associations that I would prefer to be lazily loaded in this case (but not necessarily all cases). I want a solution that I can control what is lazily loaded when I perform the query. Here's what the GiftCard Entity looks like: @Entity @Table(name = "giftCards") public class GiftCard implements Serializable { private static final long serialVersionUID = 1L; private String id_; private User buyer_; private boolean isRecipientNotificationRequested_; @Id public String getId() { return this.id_; } public void setId(String id) { this.id_ = id; } @ManyToOne @JoinColumn(name = "buyerUserId") @NotFound(action = NotFoundAction.IGNORE) public User getBuyer() { return this.buyer_; } public void setBuyer(User buyer) { this.buyer_ = buyer; } @Column(name="isRecipientNotificationRequested", nullable=false, columnDefinition="tinyint") public boolean isRecipientNotificationRequested() { return this.isRecipientNotificationRequested_; } public void setRecipientNotificationRequested(boolean isRecipientNotificationRequested) { this.isRecipientNotificationRequested_ = isRecipientNotificationRequested; } }

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• How to update application files using patching?

  - by Marek

  I am not interested in any auto update solution, such as ClickOnce or the MS Updater Block. For anyone feeling the urge to ask why not: I am already using these and there is nothing wrong with them, I would just like to learn about any efficient alternatives. I would like to publish patches = small differences that will modify existing files of the deployment with the smallest possible delta. Not only code needs to be patched, but also resource files. Patching the running code can be accomplished by maintaining two separate synchronized copies of the deployment (no on the fly changes to the running executable are required). The application itself can be xcopy deployed (to avoid MSI auto-correcting the modified files or breaking ClickOnce signatures). I would like to learn how to handle different versions of patches (e.g. there is a patch issued that fixes one error and later another patch that fixes another error (in the same file) - users may have any combination of these and there comes a third patch - in text files, this may be easy to implement, but how about executable files? (native Win32 code vs. .NET, any difference?) If the first problem is too hard to solve or unsolvable for executables, I would like to at least learn if there is a solution that implements simple patching with serial revisions - in order to install revision 5, user must have all previous revisions installed to ensure validity of the deployment. Are there any existing solutions to accomplish this? NOTE: There are a few questions on SO that may seem like duplicates, but none with a good answer. This question is about the Windows platform, preferably .NET.

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• Is there a good digraph layout library callable from C++?

  - by Steve314

  The digraphs represent finite automata. Up until now my test program has been writing out dot files for testing. This is pretty good both for regression testing (keep the verified output files in subversion, ask it if there has been a change) and for visualisation. However, there are some problems... Basically, I want something callable from C++ and which plans a layout for my states and transitions but leaves the drawing to me - something that will allow me to draw things however I want and draw on GUI (wxWidgets) windows. I also want a license which will allow commercial use - I don't need that at present, and I may very well release as open source, but I don't want to limit my options ATM. The problems with GraphViz are (1) the warnings about building from source on Windows, (2) all the unnecessary dependencies for rendering and parsing, and (3) the (presumed) lack of a documented API specifically and purely for layout. Basically, I want to be able to specify my states (with bounding rectangle sizes) and transitions, and read out positions for the states and waypoints for each transition, then draw based on those co-ordinates myself. I haven't really figured out how annotations on transitions should be handled, but there should be some kind of provision for specifying bounding-box-sizes for those, associating them with transitions, and reading out positions. Does anyone know of a library that can handle those requirements? I'm not necessarily against implementing something for myself, but in this case I'd rather avoid it if possible.

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• Using a php://memory wrapper causes errors...

  - by HorusKol

  I'm trying to extend the PHP mailer class from Worx by adding a method which allows me to add attachments using string data rather than path to the file. I came up with something like this: public function addAttachmentString($string, $name='', $encoding = 'base64', $type = 'application/octet-stream') { $path = 'php://memory/' . md5(microtime()); $file = fopen($path, 'w'); fwrite($file, $string); fclose($file); $this->AddAttachment($path, $name, $encoding, $type); } However, all I get is a PHP warning: PHP Warning: fopen() [<a href='function.fopen'>function.fopen</a>]: Invalid php:// URL specified There aren't any decent examples with the original documentation, but I've found a couple around the internet (including one here on SO), and my usage appears correct according to them. Has anyone had any success with using this? My alternative is to create a temporary file and clean up - but that will mean having to write to disc, and this function will be used as part of a large batch process and I want to avoid slow disc operations (old server) where possible. This is only a short file but has different information for each person the script emails.

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• I've made something that might be useful to the community. Now what?

  - by Chris McCall

  If the specifics are important, I made a cruisecontrol.net publisher plugin that notifies a series of phone numbers via voice, announcing the current state of the build. It uses Twilio to do so. I'd like to avoid getting hung up on the specifics of what it is I've made, as I have this question a lot, with a number of little hobby one-offs. What's the state of the art as far as making my hobby output available to the world at large? There seem to be a lot of options for open-source project hosting, community features, and what role to take in all of this. It's a little bewildering. What I'm looking for is to put this out into the wild for free and basically take a hands-off approach from there. Is that realistic? Which project hosting service can I use for free to allow developers to at least download the code, report issues and collaborate with each other to improve the product? What snags have you run into that could make me regret this decision? I'm interested in war stories, advice and guidance on making this little product available to the community where it can be used.

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• Am I abusing Policies?

  - by pmr

  I find myself using policies a lot in my code and usually I'm very happy with that. But from time to time I find myself confronted with using that pattern in situations where the Policies are selected and runtime and I have developed habbits to work around such situations. Usually I start with something like that: class DrawArrays { protected: void sendDraw() const; }; class DrawElements { protected: void sendDraw() const; }; template<class Policy> class Vertices : public Policy { using Policy::sendDraw(); public: void render() const; }; When the policy is picked at runtime I have different choices of working around the situation. Different code paths: if(drawElements) { Vertices<DrawElements> vertices; } else { Vertices<DrawArrays> vertices; } Inheritance and virtual calls: class PureVertices { public: void render()=0; }; template<class Policy> class Vertices : public PureVertices, public Policy { //.. }; Both solutions feel wrong to me. The first creates an umaintainable mess and the second introduces the overhead of virtual calls that I tried to avoid by using policies in the first place. Am I missing the proper solutions or do I use the wrong pattern to solve the problem?

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• How to correctly waitFor() a saveScreenShot() end of execution.

  - by Alain

  Here is my full first working test: var expect = require('chai').expect; var assert = require('assert'); var webdriverjs = require('webdriverjs'); var client = {}; var webdriverOptions = { desiredCapabilities: { browserName: 'phantomjs' }, logLevel: 'verbose' }; describe('Test mysite', function(){ before(function() { client = webdriverjs.remote( webdriverOptions ); client.init(); }); var selector = "#mybodybody"; it('should see the correct title', function(done) { client.url('http://localhost/mysite/') .getTitle( function(err, title){ expect(err).to.be.null; assert.strictEqual(title, 'My title page' ); }) .waitFor( selector, 2000, function(){ client.saveScreenshot( "./ExtractScreen.png" ); }) .waitFor( selector, 7000, function(){ }) .call(done); }); after(function(done) { client.end(done); }); }); Ok, it does not do much, but after working many hours to get the environement correctly setup, it passed. Now, the only way I got it working is by playing with the waitFor() method and adjust the delays. It works, but I still do not understand how to surely wait for a png file to be saved on disk. As I will deal with tests orders, I will eventually get hung up from the test script before securely save the file. Now, How can I improve this screen save sequence and avoid loosing my screenshot ? Thanks.

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• Is my method for avoiding dynamic_cast<> faster than dynamic_cast<> itself ?

  - by ereOn

  Hi, I was answering a question a few minutes ago and it raised to me another one: In one of my projects, I do some network message parsing. The messages are in the form of: [1 byte message type][2 bytes payload length][x bytes payload] The format and content of the payload are determined by the message type. I have a class hierarchy, based on a common class Message. To instanciate my messages, i have a static parsing method which gives back a Message* depending on the message type byte. Something like: Message* parse(const char* frame) { // This is sample code, in real life I obviously check that the buffer // is not NULL, and the size, and so on. switch(frame[0]) { case 0x01: return new FooMessage(); case 0x02: return new BarMessage(); } // Throw an exception here because the mesage type is unknown. } I sometimes need to access the methods of the subclasses. Since my network message handling must be fast, I decived to avoid dynamic_cast<> and I added a method to the base Message class that gives back the message type. Depending on this return value, I use a static_cast<> to the right child type instead. I did this mainly because I was told once that dynamic_cast<> was slow. However, I don't know exactly what it really does and how slow it is, thus, my method might be as just as slow (or slower) but far more complicated. What do you guys think of this design ? Is it common ? Is it really faster than using dynamic_cast<> ? Any detailed explanation of what happen under the hood when one use dynamic_cast<> is welcome !

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• Generating easy-to-remember random identifiers

  - by Carl Seleborg

  Hi all, As all developers do, we constantly deal with some kind of identifiers as part of our daily work. Most of the time, it's about bugs or support tickets. Our software, upon detecting a bug, creates a package that has a name formatted from a timestamp and a version number, which is a cheap way of creating reasonably unique identifiers to avoid mixing packages up. Example: "Bug Report 20101214 174856 6.4b2". My brain just isn't that good at remembering numbers. What I would love to have is a simple way of generating alpha-numeric identifiers that are easy to remember. Examples would be "azil3", "ulmops", "fel2way", etc. I just made these up, but they are much easier to recognize when you see many of them at once. I know of algorithms that perform trigram analysis on text (say you feed them a whole book in German) and that can generate strings that look and feel like German words. This requires lots of data, though, and makes it slightly less suitable for embedding in an application just for this purpose. Do you know of anything else? Thanks! Carl

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• How to get resultset with stored procedure calls over two linked servers?

  - by räph

  I have problems filling a temporary table with the resultset from a procedure call on a linked server, in which again a procedure on another server is called. I have a Stored Procedure sproc1 with the following code, which calls another procedure sproc2 on a linked server. SET @sqlCommand = 'INSERT INTO #tblTemp ( ModuleID, ParamID) ' + '( SELECT * FROM OPENQUERY(' + @targetServer + ', ' + '''SET FMTONLY OFF; EXEC ' + @targetDB + '.usr.sproc2 ' + @param + ''' ) )' exec ( @sqlCommand ) Now in the called sproc2 I again call a third procedure sproc3 on another linked server, which returns my resultset. SET @sqlCommand = 'EXEC ' + @targetServer +'.database.usr.sproc3 ' + @param exec ( @sqlCommand ) The whole thing doen't work, as I get an SQL error 7391 The operation could not be performed because OLE DB provider "%ls" for linked server "%ls" was unable to begin a distributed transaction. I already checked the hints at this microsoft article, but without success. But maybe, I can change the code in sproc1. Would there be some alternative to the temp table and the open query? Just calling stored procedures from server A to B to C and returning the resultset is working (I do this often in the application). But this special case with the temp table and openquery doesn't work! Or is it just not possible what I am trying to do? The microsft article states: Check the object you refer on the destination server. If it is a view or a stored procedure, or causes an execution of a trigger, check whether it implicitly references another server. If so, the third server is the source of the problem. Run the query directly on the third server. If you cannot run the query directly on the third server, the problem is not actually with the linked server query. Resolve the underlying problem first. Is this my case? PS: I can't avoid the architecture with the three servers.

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• Check for modification failure in content Integration using visualSvn sever and cruise control.net

  - by harun123

  I am using CruiseControl.net for continous integration. I've created a repository for my project using VisualSvn server (uses Windows Authentication). Both the servers are hosted in the same system (Os-Microsoft Windows Server 2003 sp2). When i force build the project using CruiseControl.net "Failed task(s): Svn: CheckForModifications" is shown as the message. When i checked the build report, it says as follows: BUILD EXCEPTION Error Message: ThoughtWorks.CruiseControl.Core.CruiseControlException: Source control operation failed: svn: OPTIONS of 'https://sp-ci.sbsnetwork.local:8443/svn/IntranetPortal/Source': **Server certificate verification failed: issuer is not trusted** (https://sp-ci.sbsnetwork.local:8443). Process command: C:\Program Files\VisualSVN Server\bin\svn.exe log **sameUrlAbove** -r "{2010-04-29T08:35:26Z}:{2010-04-29T09:04:02Z}" --verbose --xml --username ccnetadmin --password cruise --non-interactive --no-auth-cache at ThoughtWorks.CruiseControl.Core.Sourcecontrol.ProcessSourceControl.Execute(ProcessInfo processInfo) at ThoughtWorks.CruiseControl.Core.Sourcecontrol.Svn.GetModifications (IIntegrationResult from, IIntegrationResult to) at ThoughtWorks.CruiseControl.Core.Sourcecontrol.QuietPeriod.GetModifications(ISourceControl sourceControl, IIntegrationResult lastBuild, IIntegrationResult thisBuild) at ThoughtWorks.CruiseControl.Core.IntegrationRunner.GetModifications(IIntegrationResult from, IIntegrationResult to) at ThoughtWorks.CruiseControl.Core.IntegrationRunner.Integrate(IntegrationRequest request) My SourceControl node in the ccnet.config is as shown below: <sourcecontrol type="svn"> <executable>C:\Program Files\VisualSVN Server\bin\svn.exe</executable> <trunkUrl> check out url </trunkUrl> <workingDirectory> C:\ProjectWorkingDirectories\IntranetPortal\Source </workingDirectory> <username> ccnetadmin </username> <password> cruise </password> </sourcecontrol> Can any one suggest how to avoid this error?

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