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  • In a digital photo, how can I detect if a mountain is obscured by clouds?

    - by Gavin Brock
    The problem I have a collection of digital photos of a mountain in Japan. However the mountain is often obscured by clouds or fog. What techniques can I use to detect that the mountain is visible in the image? I am currently using Perl with the Imager module, but open to alternatives. All the images are taken from the exact same position - these are some samples. My naïve solution I started by taking several horizontal pixel samples of the mountain cone and comparing the brightness values to other samples from the sky. This worked well for differentiating good image 1 and bad image 2. However in the autumn it snowed and the mountain became brighter than the sky, like image 3, and my simple brightness test started to fail. Image 4 is an example of an edge case. I would classify this as a good image since some of the mountain is clearly visible. UPDATE 1 Thank you for the suggestions - I am happy you all vastly over-estimated my competence. Based on the answers, I have started trying the ImageMagick edge-detect transform, which gives me a much simpler image to analyze. convert sample.jpg -edge 1 edge.jpg I assume I should use some kind of masking to get rid of the trees and most of the clouds. Once I have the masked image, what is the best way to compare the similarity to a 'good' image? I guess the "compare" command suited for this job? How do I get a numeric 'similarity' value from this?

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  • Losing 'post' requests sent to Pylons paster server

    - by Philip McDermott
    I'm sending post requests to a Pylons server (served by paster serve), and if I send them with any frequency many don't arrive at the server. One at a time is ok, but if I fire off a few (or more) within seconds, only a small number get dealt with. If I send with no post data, or with get, it works fine, but putting just one character of data in the post fields causes massive losses. For example, sending 200, 2 will come back. Sending 100 more slowly, 10 will come back. I'm making the requests form inside a Qt application. Tis will work ok (no data): QString postFields = "" QNetworkRequest request(QUrl("http://server.com/endpoint")); QNetworkReply *reply = networkAccessManager-post(request, postFields.toAscii()); And this will result in only a fraction of the requests being dealt with: QString postFields = "" QNetworkRequest request(QUrl("http://server.com/endpoint")); QNetworkReply *reply = networkAccessManager-post(request, postFields.toAscii()); I've played around with turning on use_threadpool, and other options (threadpool_workers, threadpool_max_requests = 300), of which some combinations can alter the results slightly (best case 10 responses in 200). If I send similar requests to other (non paster) servers, the replies come back ok, so I'm almost certain its'a paster serve config issue. Any help or advice greatly appreciated. Thanks Philip

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  • How do I extract HTML content using Regex in PHP

    - by gAMBOOKa
    I know, i know... regex is not the best way to extract HTML text. But I need to extract article text from a lot of pages, I can store regexes in the database for each website. I'm not sure how XML parsers would work with multiple websites. You'd need a separate function for each website. In any case, I don't know much about regexes, so bear with me. I've got an HTML page in a format similar to this <html> <head>...</head> <body> <div class=nav>...</div><p id="someshit" /> <div class=body>....</div> <div class=footer>...</div> </body> I need to extract the contents of the body class container. I tried this. $pattern = "/<div class=\"body\">\(.*?\)<\/div>/sui" $text = $htmlPageAsIs; if (preg_match($pattern, $text, $matches)) echo "MATCHED!"; else echo "Sorry gambooka, but your text is in another castle."; What am I doing wrong? My text ends up in another castle.

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  • How to specify selector when CAKeyframeAnimation is finished?

    - by darenchow
    I'm using a CAKeyframeAnimation to animate a view along a CGPath. When the animation is done, I'd like to be able to call some other method to perform another action. Is there a good way to do this? I've looked at using UIView's setAnimationDidStopSelector:, however from the docs this looks like it only applies when used within a UIView animation block (beginAnimations and commitAnimations). I also gave it a try just in case, but it doesn't seem to work. Here's some sample code (this is within a custom UIView sub-class method): // These have no effect since they're not in a UIView Animation Block [UIView setAnimationDelegate:self]; [UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)]; // Set up path movement CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"path"]; pathAnimation.calculationMode = kCAAnimationPaced; pathAnimation.fillMode = kCAFillModeForwards; pathAnimation.removedOnCompletion = NO; pathAnimation.duration = 1.0f; CGMutablePathRef path = CGPathCreateMutable(); CGPathMoveToPoint(path, NULL, self.center.x, self.center.y); // add all points to the path for (NSValue* value in myPoints) { CGPoint nextPoint = [value CGPointValue]; CGPathAddLineToPoint(path, NULL, nextPoint.x, nextPoint.y); } pathAnimation.path = path; CGPathRelease(path); [self.layer addAnimation:pathAnimation forKey:@"pathAnimation"]; A workaround I was considering that should work, but doesn't seem like the best way, is to use NSObject's performSelector:withObject:afterDelay:. As long as I set the delay equal to the duration of the animation, then it should be fine. Is there a better way? Thanks!

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  • WCF: How can I send data while gracefully closing a connection?

    - by mafutrct
    I've got a WCF service that offers a Login method. A client is required to call this method (due to it being the only IsInitiating=true). This method should return a string that describes the success of the call in any case. If the login failed, the connection should be closed. The issue is with the timing of the close. I'd like to send the return value, then immediately close the connection. string Login (string name, string pass) { if (name != pass) { OperationContext.Current.Channel.Close (); return "fail"; } else { return "yay"; } } The MSDN states that calling Close on the channel causes an ICommunicationObject to gracefully transition from the Opened state to the Closed state. The Close method allows any unfinished work to be completed before returning. For example, finish sending any buffered messages). This did not work for me (or my understanding is wrong), as the close is executed immediately - WCF does not wait for the Login method to finish executing and return a string but closes the connection earlier. Therefore I assume that calling Close does not wait for the running method to finish. Now, how can I still return a value, then close?

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  • Invalidating Memcached Keys on save() in Django

    - by Zack
    I've got a view in Django that uses memcached to cache data for the more highly trafficked views that rely on a relatively static set of data. The key word is relatively: I need invalidate the memcached key for that particular URL's data when it's changed in the database. To be as clear as possible, here's the meat an' potatoes of the view (Person is a model, cache is django.core.cache.cache): def person_detail(request, slug): if request.is_ajax(): cache_key = "%s_ABOUT_%s" % settings.SITE_PREFIX, slug # Check the cache to see if we've already got this result made. json_dict = cache.get(cache_key) # Was it a cache hit? if json_dict is None: # That's a negative Ghost Rider person = get_object_or_404(Person, display = True, slug = slug) json_dict = { 'name' : person.name, 'bio' : person.bio_html, 'image' : person.image.extra_thumbnails['large'].absolute_url, } cache.set(cache_key) # json_dict will now exist, whether it's from the cache or not response = HttpResponse() response['Content-Type'] = 'text/javascript' response.write(simpljson.dumps(json_dict)) # Make sure it's all properly formatted for JS by using simplejson return response else: # This is where the fully templated response is generated What I want to do is get at that cache_key variable in it's "unformatted" form, but I'm not sure how to do this--if it can be done at all. Just in case there's already something to do this, here's what I want to do with it (this is from the Person model's hypothetical save method) def save(self): # If this is an update, the key will be cached, otherwise it won't, let's see if we can't find me try: old_self = Person.objects.get(pk=self.id) cache_key = # Voodoo magic to get that variable old_key = cache_key.format(settings.SITE_PREFIX, old_self.slug) # Generate the key currently cached cache.delete(old_key) # Hit it with both barrels of rock salt # Turns out this doesn't already exist, let's make that first request even faster by making this cache right now except DoesNotExist: # I haven't gotten to this yet. super(Person, self).save() I'm thinking about making a view class for this sorta stuff, and having functions in it like remove_cache or generate_cache since I do this sorta stuff a lot. Would that be a better idea? If so, how would I call the views in the URLconf if they're in a class?

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  • Which of these is pythonic? and Pythonic vs. Speed

    - by Kashyap Nadig
    Hi! I'm new to python and just wrote this module level function: def _interval(patt): """ Converts a string pattern of the form '1y 42d 14h56m' to a timedelta object. y - years (365 days), M - months (30 days), w - weeks, d - days, h - hours, m - minutes, s - seconds""" m = _re.findall(r'([+-]?\d*(?:\.\d+)?)([yMwdhms])', patt) args = {'weeks': 0.0, 'days': 0.0, 'hours': 0.0, 'minutes': 0.0, 'seconds': 0.0} for (n,q) in m: if q=='y': args['days'] += float(n)*365 elif q=='M': args['days'] += float(n)*30 elif q=='w': args['weeks'] += float(n) elif q=='d': args['days'] += float(n) elif q=='h': args['hours'] += float(n) elif q=='m': args['minutes'] += float(n) elif q=='s': args['seconds'] += float(n) return _dt.timedelta(**args) My issue is with the for loop here i.e the long if elif block, and was wondering if there is a more pythonic way of doing it. So I re-wrote the function as: def _interval2(patt): m = _re.findall(r'([+-]?\d*(?:\.\d+)?)([yMwdhms])', patt) args = {'weeks': 0.0, 'days': 0.0, 'hours': 0.0, 'minutes': 0.0, 'seconds': 0.0} argsmap = {'y': ('days', lambda x: float(x)*365), 'M': ('days', lambda x: float(x)*30), 'w': ('weeks', lambda x: float(x)), 'd': ('days', lambda x: float(x)), 'h': ('hours', lambda x: float(x)), 'm': ('minutes', lambda x: float(x)), 's': ('seconds', lambda x: float(x))} for (n,q) in m: args[argsmap[q][0]] += argsmap[q][1](n) return _dt.timedelta(**args) I tested the execution times of both the codes using timeit module and found that the second one took about 5-6 seconds longer (for the default number of repeats). So my question is: 1. Which code is considered more pythonic? 2. Is there still a more pythonic was of writing this function? 3. What about the trade-offs between pythonicity and other aspects (like speed in this case) of programming? p.s. I kinda have an OCD for elegant code. EDITED _interval2 after seeing this answer: argsmap = {'y': ('days', 365), 'M': ('days', 30), 'w': ('weeks', 1), 'd': ('days', 1), 'h': ('hours', 1), 'm': ('minutes', 1), 's': ('seconds', 1)} for (n,q) in m: args[argsmap[q][0]] += float(n)*argsmap[q][1]

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  • Authlogic Current User Question - hiding admin links...

    - by bgadoci
    I think I am missing something while using the Authlogic gem w/ Rails. To set the stage I have multiple users and each user can create posts and comments. Upon the display of a post or comment I would like to give the user who created them the option to edit or destroy. I am successfully using the following code to hide and show elements based on if a user is logged in or not but can't seem to find out how to only show these links to the actual user who created them...not any user that is logged in. <% if current_user %> <%= link_to 'Edit', edit_question_path(question) %> | <%= link_to 'Destroy', question, :confirm => 'Are you sure?', :method => :delete %> <% else %> <p>nothing to see here</p> <% end %> Here is the def of current_user located in the application controller in case I need to change something here. class ApplicationController < ActionController::Base helper :all # include all helpers, all the time protect_from_forgery # See ActionController::RequestForgeryProtection for details# helper_method :current_user private def current_user_session return @current_user_session if defined?(@current_user_session) @current_user_session = UserSession.find end def current_user return @current_user if defined?(@current_user) @current_user = current_user_session && current_user_session.record end end

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  • Best Practice for Uploading Many (2000+) Images to A Server

    - by bob
    Hello, I have a general question about this. When you have a gallery, sometimes people need to upload 1000's of images at once. Most likely, it would be done through a .zip file. What is the best way to go about uploading this sort of thing to a server. Many times, server have timeouts etc. that need to be accounted for. I am wondering what kinds of things should I be looking out for and what is the best way to handle a large amount of images being uploaded. I'm guessing that you would allow a user to upload a zip file (assuming the timeout does not effect you), and this zip file is uploaded to a specific directory, lets assume in this case a directory is created for each user in the system. You would then unzip the directory on the server and scan the user's folder for any directories containing .jpg or .png or .gif files (etc.) and then import them into a table accordingly. I'm guessing labeled by folder name. What kind of server side troubles could I run into? I'm aware that there may be many issues. Even general ideas would be could so I can then research further. Thanks! Also, I would be programming in Ruby on Rails but I think this question applies accross any language.

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  • Can't operator == be applied to generic types in C#?

    - by Hosam Aly
    According to the documentation of the == operator in MSDN, For predefined value types, the equality operator (==) returns true if the values of its operands are equal, false otherwise. For reference types other than string, == returns true if its two operands refer to the same object. For the string type, == compares the values of the strings. User-defined value types can overload the == operator (see operator). So can user-defined reference types, although by default == behaves as described above for both predefined and user-defined reference types. So why does this code snippet fail to compile? void Compare<T>(T x, T y) { return x == y; } I get the error Operator '==' cannot be applied to operands of type 'T' and 'T'. I wonder why, since as far as I understand the == operator is predefined for all types? Edit: Thanks everybody. I didn't notice at first that the statement was about reference types only. I also thought that bit-by-bit comparison is provided for all value types, which I now know is not correct. But, in case I'm using a reference type, would the the == operator use the predefined reference comparison, or would it use the overloaded version of the operator if a type defined one? Edit 2: Through trial and error, we learned that the == operator will use the predefined reference comparison when using an unrestricted generic type. Actually, the compiler will use the best method it can find for the restricted type argument, but will look no further. For example, the code below will always print true, even when Test.test<B>(new B(), new B()) is called: class A { public static bool operator==(A x, A y) { return true; } } class B : A { public static bool operator==(B x, B y) { return false; } } class Test { void test<T>(T a, T b) where T : A { Console.WriteLine(a == b); } }

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  • jQuery performance

    - by jAndy
    Hi Folks, imagine you have to do DOM manipulation like a lot (in my case, it's kind of a dynamic list). Look at this example: var $buffer = $('<ul/>', { 'class': '.custom-example', 'css': { 'position': 'absolute', 'top': '500px' } }); $.each(pages[pindex], function(i, v){ $buffer.append(v); }); $buffer.insertAfter($root); "pages" is an array which holds LI elements as jQuery object. "$root" is an UL element What happens after this code is, both UL's are animated (scrolling) and finally, within the callback of animate this code is executed: $root.detach(); $root = $buffer; $root.css('top', '0px'); $buffer = null; This works very well, the only thing I'm pi**ed off is the performance. I do cache all DOM elements I'm laying a hand on. Without looking too deep into jQuery's source code, is there a chance that my performance issues are located there? Does jQuery use DocumentFragments to append things? If you create a new DOM element with var new = $('<div/>') it is only stored in memory at this point isnt it?

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  • Counting the number of objects that meets a certain criteria

    - by Candy Chiu
    The title doesn't tell the complete story. Please read the message. I have two objects: Adult and Child. Child has a boolean field isMale, and a reference to Adult. Adult doesn't reference Child. public class Adult { long id; } public class Child { long id; boolean isMale; Adult parent; } I want to create a query to list the number of sons each adult has including adults who don't have any sons. I tried: Query 1 SELECT adult, COUNT(child) FROM Child child RIGHT OUTER JOIN child.parent as adult WHERE child.isMale='true' GROUP BY adult which translates to sql select adult.id as col_0_0_, count(child.id) as col_1_0_, ... {omit properties} from Child child right outer join Adult adult on child.parentId=adult.id where child.isMale = 'true' group by adult.id Query 1 doesn't pick up adults that don't have any sons. Query 2: SELECT adult, COUNT(child.isMale) FROM Child child RIGHT OUTER JOIN child.parent as adult GROUP BY adult translates to sql: select adult.id as col_0_0_, count(child.id) as col_1_0_, ... {omit properties} from Child child right outer join Adult adult on child.parentId=adult.id group by adult.id Query 2 doesn't have the right count of sons. Basically COUNT doesn't evaluate isMale. The where clause in Query 1 filtered out Adults with no sons. How do I build a HQL or a Criteria query for this use case? Thanks.

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  • Which Database to choose?

    - by Sundar
    I have the following criteria Database should be protected with a username and password. It should not be possible to copy the database file and use it else were like MS Access. There will be no central database server. Each machine will run their own database server locally and user will initiate synchronization. Concept is inspired from distributed version control system like Git. So it should have good replication support. Strong consistency is not needed. Users will synchronize each other database when they need. In case of conflicts it should be possible to find the conflict and present it (from application) to the user for fixing it. Revisions of data if available it will be good. e.g. Entire history of change to a invoice. I explored document oriented database and inclined towards the same. But I dont know what to choose. Database is small it will not reach even 1GB in the next few years (say 3 years). Please feel free to suggest any database which you think might be suitable. Any pointers is highly appreciated. Thanks in advance.

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  • httprequest handle time delays till having response

    - by bourax webmaster
    I have an application that calls a function to send JSON object to a REST API, my problem is how can I handle time delays and repeat this function till i have a response from the server in case of interrupted network connexion ?? I try to use the Handler but i don't know how to stop it when i get a response !!! here's my function that is called when button clicked : protected void sendJson(final String name, final String email, final String homepage,final Long unixTime,final String bundleId) { Thread t = new Thread() { public void run() { Looper.prepare(); //For Preparing Message Pool for the child Thread HttpClient client = new DefaultHttpClient(); HttpConnectionParams.setConnectionTimeout(client.getParams(), 10000); //Timeout Limit HttpResponse response; JSONObject json = new JSONObject(); //creating meta object JSONObject metaJson = new JSONObject(); try { HttpPost post = new HttpPost("http://util.trademob.com:5000/cards"); metaJson.put("time", unixTime); metaJson.put("bundleId", bundleId); json.put("name", name); json.put("email", email); json.put("homepage", homepage); //add the meta in the root object json.put("meta", metaJson); StringEntity se = new StringEntity( json.toString()); se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json")); post.setEntity(se); String authorizationString = "Basic " + Base64.encodeToString( ("tester" + ":" + "tm-sdktest").getBytes(), Base64.NO_WRAP); //Base64.NO_WRAP flag post.setHeader("Authorization", authorizationString); response = client.execute(post); String temp = EntityUtils.toString(response.getEntity()); Toast.makeText(getApplicationContext(), temp, Toast.LENGTH_LONG).show(); } catch(Exception e) { e.printStackTrace(); } Looper.loop(); //Loop in the message queue } }; t.start(); }

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  • LinkedIn API returning extra/incorrect login prompt

    - by Paul Osetinsky
    I have a Rails application running the omniauth-linkedin gem and linkedin gem (essentialy an API wrapper). When a user logs in, they receive a primary login prompt that displays to them the correct scopes (FULL PROFILE and EMAIL ADDRESS), as below: However, after they log in, they get another login prompt that should not come up, and that ignores the initial scope request. It tells them that LinkedIN is only requesting their PROFILE OVERVIEW, which is incorrect: The problem must lie in my auth_controller, and I think it has do to with the url that is created in one of the authentication stages (definitely right after the user enters their LinkedIn authentication credentials). Here is my auth_controller: require 'linkedin' class AuthController < ApplicationController def auth client = LinkedIn::Client.new(ENV['LINKEDIN_KEY'], ENV['LINKEDIN_SECRET']) request_token = client.request_token(:oauth_callback => "http://#{request.host_with_port}/callback") session[:rtoken] = request_token.token session[:rsecret] = request_token.secret redirect_to client.request_token.authorize_url end def callback client = LinkedIn::Client.new(ENV['LINKEDIN_KEY'], ENV['LINKEDIN_SECRET']) if session[:atoken].nil? pin = params[:oauth_verifier] atoken, asecret = client.authorize_from_request(session[:rtoken], session[:rsecret], pin) session[:atoken] = atoken session[:asecret] = asecret @user = current_user @user.uid = client.profile(:fields => ["id"]).id flash.now[:success] = 'Signed in with LinkedIn.' else client.authorize_from_access(session[:atoken], session[:asecret]) @user.uid = client.profile(:fields => ["id"]).id flash.now[:success] = 'Signed in with LinkedIn.' end @user = current_user @user.save redirect_to current_user end end Just in case, here is my omniauth.rb file that states the scopes I am requesting for my application: Rails.application.config.middleware.use OmniAuth::Builder do provider :linkedin, ENV['LINKEDIN_KEY'], ENV['LINKEDIN_SECRET'], :scope => 'r_fullprofile r_emailaddress', :fields => ['id', 'email-address', 'first-name', 'last-name', 'headline', 'industry', 'picture-url', 'public-profile-url', 'location', 'positions', 'educations'] end Can't figure out how to get rid of that second unnecessary and misleading prompt from LinkedIn and would appreciate any guidance! Thank you.

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  • Binding ElementName

    - by zvi
    Hello First Sorry for my English. I wanted to ask why ElementName does not work the first case, and work in the second. I give the two sections of code . the firts not work <Button Name="button1" Width="100" > <Button.LayoutTransform> <ScaleTransform x:Name="ttt" ScaleX="3" ScaleY="6"/> </Button.LayoutTransform> <Button.Triggers> <EventTrigger RoutedEvent="Path.Loaded"> <EventTrigger.Actions> <BeginStoryboard> <Storyboard RepeatBehavior="Forever"> <DoubleAnimation Storyboard.Target="{Binding ElementName=ttt}" Storyboard.TargetProperty="ScaleX" From="10" To="5" Duration="0:0:1" /> </Storyboard> </BeginStoryboard> </EventTrigger.Actions> </EventTrigger> </Button.Triggers> Button </Button> But it does work <Button Name="button1" Width="100" > <Button.LayoutTransform> <ScaleTransform x:Name="ttt" ScaleX="3" ScaleY="6"/> </Button.LayoutTransform> <Button.Triggers> <EventTrigger RoutedEvent="Path.Loaded"> <EventTrigger.Actions> <BeginStoryboard> <Storyboard RepeatBehavior="Forever"> <DoubleAnimation Storyboard.Target="{Binding ElementName=button1}" Storyboard.TargetProperty="Width" From="100" To="50" Duration="0:0:1" /> </Storyboard> </BeginStoryboard> </EventTrigger.Actions> </EventTrigger> </Button.Triggers> Button </Button> I know I can use Storyboard.TargetName .

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  • Core Data + Core Animation/CALayer together??

    - by ivanTheTerrible
    I am making an Cocoa app with custom interfaces. So far I have implemented one version of the app using CALayer doing the rendering, which has been great given the hierarchical structure of CALayers, and its [hitTest:] function for handling mouse events. In this early version, the model of the app are my custom classes. However, as the program grows I feel the urge of using Core Data for the model, not just for the ease of binding/undo management, but also want to try out the new technology. My method so far: In Core Data: creating a Block entity, with attributes xPos, yPos, width, height...etc. Then, creating a BlockView : CALayer class for drawing, which uses methods such as self.position.x = [self valueForKey:@"xPos"] to fetch the values from the model. In this case, every BlockView object has to also keep a local copy of xPos, which is NOT good. Do any of you guys have better suggestions? Edit: This app is a information visualization tool. So the positions, dimensions of the blocks are important, and should be persisted for later analysis.

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  • JBoss Developer Studio exploaded SAR/EAR/WAR deployment

    - by dr_hoppa
    I am new to JBoss DS and I could not figur out is how to make a folder from my project deployable, exploded SAR in my case. If I create a new server in the JBoss server view / JBoss AS perspective and select a SAR and make it a deployable then the SAR file can be deployed on the JBoss server. Another approch that I have tryed is to make the *-service.xml file as a deployable element, same procedure as with the SAR file, and to add the Eclipse project as a dependency to the classpath of the server 'Open launch configuration' / 'Classpath' after dooing this I got an error from JBoss telling me that the JBoss classes are not found. The compromise solution that I have found is to create a junction/symlink from the output of the Eclipse project 'bin' into the JBoss 'serve//deploy/xxx.sar' this is a temporary solution but will not scale in the future as multiple services must be created. What I would need: I would need to have the ability to make the exploded folder as 'mark deployable' and to be have the classes/*service.xml files loaded from there and to have hot-deployability for them. Any sugestions would help.

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  • Parsing Lisp S-Expressions with known schema in C#

    - by Drew Noakes
    I'm working with a service that provides data as a Lisp-like S-Expression string. This data is arriving thick and fast, and I want to churn through it as quickly as possible, ideally directly on the byte stream (it's only single-byte characters) without any backtracking. These strings can be quite lengthy and I don't want the GC churn of allocating a string for the whole message. My current implementation uses CoCo/R with a grammar, but it has a few problems. Due to the backtracking, it assigns the whole stream to a string. It's also a bit fiddly for users of my code to change if they have to. I'd rather have a pure C# solution. CoCo/R also does not allow for the reuse of parser/scanner objects, so I have to recreate them for each message. Conceptually the data stream can be thought of as a sequence of S-Expressions: (item 1 apple)(item 2 banana)(item 3 chainsaw) Parsing this sequence would create three objects. The type of each object can be determined by the first value in the list, in the above case "item". The schema/grammar of the incoming stream is well known. Before I start coding I'd like to know if there are libraries out there that do this already. I'm sure I'm not the first person to have this problem.

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  • Program Structure Design Tools? (Top Down Design)

    - by Lee Olayvar
    I have been looking to expand my methodologies to better involve Unit testing, and i stumbled upon Behavioral Driven Design (Namely Cucumber, and a few others). I am quite intrigued by the concept as i have never been able to properly design top down, only because keeping track of the design gets lost without a decent way to record it. So on that note, in a mostly language agnostic way, are there any useful tools out there i am (probably) unaware of? Eg, i have often been tempted to try building flow charts for my programs, but i am not sure how much that will help, and it seems a bit confusing to me how i could make a complex enough flow chart to handle the logic of a full program, and all its features.. ie, it just seems like flow charts would be limiting in the design scheme.. or possibly grow to an unmaintainable scale. BDD methods are nice, but with a system that is so tied to structure, tying into the language and unit testing seems like a must (for it to be worth it) and it seems to be hard to find something to work well with both Python and Java (my two main languages). So anyway.. on that note, any comments are much appreciated. I have searched around on here and it seems like top down design is a well discussed topic, but i haven't seen too much reference to tools themselves, eg, flow chart programs, etc. I am on Linux, if it matters (in the case of programs).

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  • UIView coordinate transforms on rotation during keyboard appearance

    - by SG
    iPad app; I'm trying to resize my view when the keyboard appears. It amounts to calling this code at appropriate times: CGRect adjustedFrame = self.frame; adjustedFrame.size.height -= keyboardFrame.size.height; [self setFrame:adjustedFrame]; Using this technique for a view contained in a uisplitview-based app works in all 4 orientations, but I've since discovered that a vanilla uiview-based app does not work. What happens is that apparently the uisplitview is smart enough to convert the coordinates of its subviews (their frame) such that the origin is in the "viewer's top left" regardless of the orientation. However, a uiview is not able to correctly report these coordinates. Though the origin is reported as (0,0) in all orientations, the view's effective origin is always as if the ipad were upright. What is weird about this is that the view correctly rotates and draws, but it always originates in the literal device top left. How can I get the view to correctly make its origin the "top left" to the viewer, not the device's fixed top left? What am I missing? Please, for something so trivial I've spent about 6 hours on this already with every brute force technique and research angle I could think of. This is the original source which doesn't work in this case: http://stackoverflow.com/questions/1951826/move-up-uitoolbar

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  • Parsing a string, Grammar file.

    - by defn
    How would I separate the below string into its parts. What I need to separate is each < Word including the angle brackets from the rest of the string. So in the below case I would end up with several strings 1. "I have to break up with you because " 2. "< reason " (without the spaces) 3. " . But Let's still " 4. "< disclaimer " 5. " ." I have to break up with you because <reason> . But let's still <disclaimer> . below is what I currently have (its ugly...) boolean complete = false; int begin = 0; int end = 0; while (complete == false) { if (s.charAt(end) == '<'){ stack.add(new Terminal(s.substring(begin, end))); begin = end; } else if (s.charAt(end) == '>') { stack.add(new NonTerminal(s.substring(begin, end))); begin = end; end++; } else if (end == s.length()){ if (isTerminal(getSubstring(s, begin, end))){ stack.add(new Terminal(s.substring(begin, end))); } else { stack.add(new NonTerminal(s.substring(begin, end))); } complete = true; } end++;

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  • Is there added overhead to looking up a column in a DataTable by name rather than by index?

    - by Ben McCormack
    In a DataTable object, is there added overhead to looking up a column value by name thisRow("ColumnA") rather than by the column index thisRow(0)? In which scenarios might this be an issue. I work on a team that has lots of experience writing VB6 code and I noticed that didn't do column lookups by name for DataTable objects or data grids. Even in .NET code, we use a set of integer constants to reference column names in these types of objects. I asked our team lead why this was so, and he mentioned that in VB6, there was a lot of overhead in looking up data by column name rather than by index. Is this still true for .NET? Example code (in VB.NET, but same applies to C#): Public Sub TestADOData() Dim dt As New DataTable 'Set up the columns in the DataTable ' dt.Columns.Add(New DataColumn("ID", GetType(Integer))) dt.Columns.Add(New DataColumn("Name", GetType(String))) dt.Columns.Add(New DataColumn("Description", GetType(String))) 'Add some data to the data table ' dt.Rows.Add(1, "Fred", "Pitcher") dt.Rows.Add(3, "Hank", "Center Field") 'Method 1: By Column Name ' For Each r As DataRow In dt.Rows Console.WriteLine( _ "{0,-2} {1,-10} {2,-30}", r("ID"), r("Name"), r("Description")) Next Console.WriteLine() 'Method 2: By Column Name ' For Each r As DataRow In dt.Rows Console.WriteLine("{0,-2} {1,-10} {2,-30}", r(0), r(1), r(2)) Next End Sub Is there an case where method 2 provides a performance advantage over method 1?

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  • Detecting Asymptotes in a Graph

    - by nasufara
    I am creating a graphing calculator in Java as a project for my programming class. There are two main components to this calculator: the graph itself, which draws the line(s), and the equation evaluator, which takes in an equation as a String and... well, evaluates it. To create the line, I create a Path2D.Double instance, and loop through the points on the line. To do this, I calculate as many points as the graph is wide (e.g. if the graph itself is 500px wide, I calculate 500 points), and then scale it to the window of the graph. Now, this works perfectly for most any line. However, it does not when dealing with asymptotes. If, when calculating points, the graph encounters a domain error (such as 1/0), the graph closes the shape in the Path2D.Double instance and starts a new line, so that the line looks mathematically correct. Example: However, because of the way it scales, sometimes it is rendered correctly, sometimes it isn't. When it isn't, the actual asymptotic line is shown, because within those 500 points, it skipped over x = 2.0 in the equation 1 / (x-2), and only did x = 1.98 and x = 2.04, which are perfectly valid in that equation. Example: In that case, I increased the window on the left and right one unit each. My question is: Is there a way to deal with asymptotes using this method of scaling so that the resulting line looks mathematically correct? I myself have thought of implementing a binary search-esque method, where, if it finds that it calculates one point, and then the next point is wildly far away from the last point, it searches in between those points for a domain error. I had trouble figuring out how to make it work in practice, however. Thank you for any help you may give!

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  • How to figure out what error my Java Eclipse project has?

    - by Greg Mattes
    I've created a Java project from existing source with an Ant build script in Eclipse. I cannot run my project because Eclipse tells me that there is at least one error in it. Now, I know that the project runs fine on the command line, so I suspect an Eclipse configuration error. As far as I can tell, the only feedback that I have from Eclipse is a little red X on my project in the Package Explorer window and dialog window when I try to run the project says there are errors in the project This is all wonderful, but what is the error? Is there a "show me the next error" button somewhere? In the past, on other Eclipse projects, I've notice other little red X's on folders containing source files with errors, the little red X's appear on the source files as well. I scanned (manually) through all of the source files and I haven't found any other red X's (again, where is the "next error" button?). If I select the "Proceed" button I am greeted with a java.lang.NoClassDefFoundError for my main class, which makes me suspect a classpath issue. I've checked the classpath, and I'm fairly certain that it's correct. Is there a way to see the exact jvm command line that Eclipse is invoking? I realize that it might be invoking the JVM programmatically, and not on a "real" command line. In any case, is there a way, other than the run configuration dialog, to see what is actually happening when I hit the "Proceed" button?

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