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  • Flash: Closest point to MovieClip

    - by LiraNuna
    I need to constrain a point inside a DisplayObject given to me by the artist. I got it working but only for the occations where the cursor is still inside bounds. The limited object is called limited. function onSqMouseMove(event:MouseEvent) { if(bounds.hitTestPoint(event.stageX, event.stageY, true)) { limited.x = event.stageX; limited.y = event.stageY; } else { /* Find closest point in the Sprite */ } } limited.addEventListener(MouseEvent.MOUSE_DOWN, function(event:MouseEvent) { stage.addEventListener(MouseEvent.MOUSE_MOVE, onSqMouseMove); }); limited.addEventListener(MouseEvent.MOUSE_UP, function(event:MouseEvent) { stage.removeEventListener(MouseEvent.MOUSE_MOVE, onSqMouseMove); }); How do I go about implementing the other half of the function? I am aware Sprite's startDrag accepts arguments, where the second one is the constraint rectangle, but in my case, bounds are an arbitrary shape. When the object is dragged outside the bounds, I want to calculate the closest point from the cursor to bounds' polygon. Just to note that bounds can have 'holes'.

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  • How do you work around memcached's key/value limitations?

    - by mjy
    Memcached has length limitations for keys (250?) and values (roughtly 1MB), as well as some (to my knowledge) not very well defined character restrictions for keys. What is the best way to work around those in your opinion? I use the Perl API Cache::Memcached. What I do currently is store a special string for the main key's value if the original value was too big ("parts:<number") and in that case, I store <number parts with keys named 1+<main key, 2+<main key etc.. This seems "OK" (but messy) for some cases, not so good for others and it has the intrinsic problem that some of the parts might be missing at any time (so space is wasted for keeping the others and time is wasted reading them). As for the key limitations, one could probably implement hashing and store the full key (to work around collisions) in the value, but I haven't needed to do this yet. Has anyone come up with a more elegant way, or even a Perl API that handles arbitrary data sizes (and key values) transparently? Has anyone hacked the memcached server to support arbitrary keys/values?

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  • MSVC 2003 doesn't see any definitions from a nested include file

    - by ezpresso
    I have a piece of code with COM class declaration as follows: #include "PathTypes.h" MIDL_INTERFACE("552C7555-0555-4444-BA86-56CF39AAFFFF") IPathCalc : public IUnknown { virtual HRESULT STDMETHODCALLTYPE GetLocation( /* [retval][out] */ GeoLocation* pLoc) = 0; virtual HRESULT STDMETHODCALLTYPE SetLocation( /* [in] */ GeoLocation* pLoc) = 0; ... }; Below is the contents of PathTypes.h file: #if !defined(PATHCALC_TYPES_INCLUDED) #define PATHCALC_TYPES_INCLUDED #include "libastro/AstronomyStructs.h" #endif And the libastro/AstronomyStructs.h from an external cross-platform library: #ifndef _ASTRONOMY_STRUCTS_INCLUDED #define _ASTRONOMY_STRUCTS_INCLUDED typedef struct { double lattitude; double longitude; } GeoLocation; ... #endif /* _ASTRONOMY_STRUCTS_INCLUDED */ When I'm trying to build this code with g++ everything goes well. That's not the case with MSVC 2003 which returns error C2061: syntax error : identifier 'GeoLocation'. Seems like MSVC doesn't "see" the definitions from the libastro/AstronomyStructs.h file. When I replace #include "PathTypes.h" with #include "libastro/AstronomyStructs.h" the code compiles without errors. How to make MSVC 2003 to actually "see" the definitions from the nested include files?

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  • Sync two SqlExpress using NHibernate

    - by Christian
    Hello, I am creating a simple project management system which uses NHibernate for object storage. The underlying database is SQL express (at least currently for development). The client runs on either the desktop or laptop. I know I could use web-services and store the DB only on the desktop, but this would force the desktop to be available all the time. I am currently thinking about duplicating the DB, having two instances with "different data". To clarify, we are not talking about a productive app here, its a prototype. One way to achieve this very simple would be the following process: Client: Check if desktop DB is available (through web service) Client: If yes, use desktop storage, no problem here Client: If not, use own DB as storage Client: Poll desktop regulary, as soon as it comes on, sync Client: Switch to desktop storage ... Desktop: Do not attempt any DB operation before checking for required sync Desktop: If sync needed, do it... My question is now, how would you sync? Assume 4 or 5 types of objects, all have GUID as identifiers. Would you always manually "lazy load" all objects of a certain type and feed them to the DB. Would you always drop the whole desktop DB in case the client DB may be newer and out of sync? Again, I want to stress out, I am not assuming any conflicts or stale data, I basically just want to "copy the whole DB from the client". Would you use NHibernate for this? Or would you separate the copy process? When I think about it, my questions comes down to this: Is there any function from NHibernate: SyncDBs_SourceWins_(SourceDB, TargetDB) Thanks for help, Chris

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  • Fastest XML parser for small, simple documents in Java

    - by Varkhan
    I have to objectify very simple and small XML documents (less than 1k, and it's almost SGML: no namespaces, plain UTF-8, you name it...), read from a stream, in Java. I am using JAXP to process the data from my stream into a Document object. I have tried Xerces, it's way too big and slow... I am using Dom4j, but I am still spending way too much time in org.dom4j.io.SAXReader. Does anybody out there have any suggestion on a faster, more efficient implementation, keeping in mind I have very tough CPU and memory constraints? [Edit 1] Keep in mind that my documents are very small, so the overhead of staring the parser can be important. For instance I am spending as much time in org.xml.sax.helpers.XMLReaderFactory.createXMLReader as in org.dom4j.io.SAXReader.read [Edit 2] The result has to be in Dom format, as I pass the document to decision tools that do arbitrary processing on it, like switching code based on the value of arbitrary XPaths, but also extracting lists of values packed as children of a predefined node. [Edit 3] In any case I eventually need to load/parse the complete document, since all the information it contains is going to be used at some point. (This question is related to, but different from, http://stackoverflow.com/questions/373833/best-xml-parser-for-java )

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  • cannot modify header information puzzler

    - by outofmyleague_lucy
    hi im out of my league i have written what has now become identical code for two sites hosted on different servers. the first worked perfectly and i have therefore used it to compare the second to.from a login for i am directing to a loginaction.php when i include the db_connect.php ie <?php session_start(); include 'db_connect.php'; $user=$_POST['formUser'] $password=$_POST['formPassword']etc ? i am returning cannot modify header information header info already sent, but when i include the content of the db_connect ie <?php session_start(); $connect = mysql_connect("localhost", "user", "pass"); mysql_select_db(db_name, $connection); $user=$_POST['formUser'] $password=$_POST['formPassword']etc ? it works. any ideas? edit - requested error message Warning: Cannot modify header information - headers already sent by (output started at /home/avenncou/public_html/include/db_connect.php:4) in /home/avenncou/public_html/include/loginaction.php on line 14 at line 14 the is a header("Location: {$_SERVER["HTTP_REFERER"]}"); edit - requested db_connect.php <?php $connection = mysql_connect("localhost", "user", "pass");// or die ("Unable to connect!"); mysql_select_db("db", $connection);// or die ("Unable to select database!"); ?> that is all of it (dies commented out in case thats where the error was)!!!

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  • Performance of Multiple Joins

    - by geeko
    Greetings Overflowers, I need to query against objects with many/complex spacial conditions. In relational databases that is translated to many joins (possibly 10+). I'm new to this business and wondering whether to go with MS SQL Server 2008 R2 or Oracle 11g or document-based solutions such as RavenDB or simply go with some spacial database (GIS)... Any thoughts ? Regards UPDATE: Thank you all for your answers. Would anybody opt for document/spatial databases ? My database would consist of tens of millions to few billion records. Mostly read-only. Almost no updates unless in case of mistakes in input. Overnight inserts and not that frequent. The join tables are predicted beforehand but the number of self joins (tables joining themselves multiple times) is not. Small pages of results from such queries are going to be viewed on an highly interactive website so response time is critical. Any predictions on how this can perform on MS SQL Server 2008 R2 or Oracle 11g ? I'm also concerned about boosting performance by adding more servers, which one scales better ? How about PostgresQL ?

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  • Partioning with Hibernate

    - by Alex
    Hello, We have a requirement to delete data in the range of 200K from database everyday. Our application is Java/JEE based using Oracle DB and Hibernate ORM tool. We explored various options like Hibernate batch processing Stored procedure Database partitioning Our DBA suggests database partitioning is the best way to go, so we can easily recreate and drop the partitioned table everyday. Now the issue is we have 2 kinds of data, one which we want to delete everyday and the other which we want to keep it. Suppose this data is stored in table "Trade". Now with partitioning, we have 2 tables "Trade". We have already existing Hibernate based DAO layer to fetch/store trades from/to DB. When we decide to partition the database, how can we control the trades to go in which of the two tables through hibernate. Basically I want , the trades need to be deleted by end of the day, to go in partitioned table and the trades I want to keep, in main table. Please suggest how can this be possible with Hibernate. We may add an additional column to identify the trades to be deleted but how can we ensure these trades should go to partitioned trade table using hibernate. I would appreciate if someone can suggest any better approach in case we are on wrong path.

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  • Oracle Forms on-button-pressed trigger to solve three scenarios

    - by DBase486
    Hello, I'm writing a when-button-pressed trigger on a save button for an Oracle Forms 6i form, and it has to fulfill a couple of scenarios. Here's some background information: the fields we're primarily concerned with are: n_number, alert_id, end_date For all three scenarios we are comparing candidate records against the following records in the database (for the sake of argument, let's assume they're the only records in the database so far): alert_id|| n_number|| end_date ------------------------------------- 1|| 5|| _______ 2|| 6|| 10/25/2009 Scenario 1: The user enters a new record: alert_id 1 n_number 5 end_date NULL Objective: prevent the user from committing duplicate rows Scenario 2: The user enters a new record: alert_id 1 n_number 10 end_date NULL Objective: Notify the user that this alert_id already exists, but allow the user the ability to commit the row, if desired. Scenario 3: The user enters a new record: alert_id 2 n_number 6 end_date NULL Objective: Notify the user that this alert_id has occurred in the past (i.e. it has a not-null end_date), but allow the user to commit the row, if desired. I've written the code, which seems to comply with the first two scenarios, but prevents me from fulfilling the third. Issues: When I enter the third scenario case, I am prompted to commit the record, but when I attempt this, the "duplicate_stop" alert pops up, preventing me. Issues: I'm getting the following error: ORA-01843: not a valid month. While testing the code for the third scenario in Toad (hard-coding the values, etc) things seemed to be fine. Why would I encounter these problems at run-time? Help is very much appreciated. Thank you

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  • Java Concurrency in practice sample question

    - by andy boot
    I am reading "Java Concurrency in practice" and looking at the example code on page 51. This states that if a thread has references to a shared object then other threads may be able to access that object before the constructor has finished executing. I have tried to put this into practice and so I wrote this code thinking that if I ran it enough times a RuntimeException("World is f*cked") would occur. But it isn't doing. Is this a case of the Java spec not guaranting something but my particular implementation of java guaranteeing it for me? (java version: 1.5.0 on Ubuntu) Or have I misread something in the book? Code: (I expect an exception but it is never thrown) public class Threads { private Widgit w; public static void main(String[] s) throws Exception { while(true){ Threads t = new Threads(); t.runThreads(); } } private void runThreads() throws Exception{ new Checker().start(); w = new Widgit((int)(Math.random() * 100) + 1); } private class Checker extends Thread{ private static final int LOOP_TIMES = 1000; public void run() { int count = 0; for(int i = 0; i < LOOP_TIMES; i++){ try { w.checkMe(); count++; } catch(NullPointerException npe){ //ignore } } System.out.println("checked: "+count+" times out of "+LOOP_TIMES); } } private static class Widgit{ private int n; private int n2; Widgit(int n) throws InterruptedException{ this.n = n; Thread.sleep(2); this.n2 = n; } void checkMe(){ if (n != n2) { throw new RuntimeException("World is f*cked"); } } } }

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  • Message sent to deallocated instance which has never been released

    - by Jakub
    Hello, I started dealing with NSOperations and (as usual with concurrency) I'm observing strange behaviour. In my class I've got an instance variable: NSMutableArray *postResultsArray; when one button in the UI is pressed I initialize the array: postResultsArray = [NSMutableArray array]; and setup the operations (together with dependencies). In the operations I create a custom object and try to add to the array: PostResult *result = [[PostResult alloc] initWithServiceName:@"Sth" andResult:someResult]; [self.postResultsArray addObject:result]; and while adding I get: -[CFArray retain]: message sent to deallocated instance 0x3b40c30 which is strange as I don't release the array anywhere in my code (I did, but when the problem started to appear I commented all the release operations to be sure that they are not the case). I also used to have @synchronized section like below: PostResult *result = [[PostResult alloc] initWithServiceName:@"Sth" andResult:someResult]; @synchronized (self.postResultsArray) { [self.postResultsArray addObject:result]; } but the problem was the same (however, the error was for the synchronized operation). Any ideas what I may be doing wrong?

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  • Sorcery/Capybara: Cannon log in with :js => true

    - by PlankTon
    I've been using capybara for a while, but I'm new to sorcery. I have a very odd problem whereby if I run the specs without Capybara's :js = true functionality I can log in fine, but if I try to specify :js = true on a spec, username/password cannot be found. Here's the authentication macro: module AuthenticationMacros def sign_in user = FactoryGirl.create(:user) user.activate! visit new_sessions_path fill_in 'Email Address', :with => user.email fill_in 'Password', :with => 'foobar' click_button 'Sign In' user end end Which is called in specs like this: feature "project setup" do include AuthenticationMacros background do sign_in end scenario "creating a project" do "my spec here" end The above code works fine. However, IF I change the scenario spec from (in this case) scenario "adding questions to a project" do to scenario "adding questions to a project", :js => true do login fails with an 'incorrect username/password' combination. Literally the only change is that :js = true. I'm using the default capybara javascript driver. (Loads up Firefox) Any ideas what could be going on here? I'm completely stumped. I'm using Capybara 2.0.1, Sorcery 0.7.13. There is no javascript on the sign in page and save_and_open_page before clicking 'sign in' confirms that the correct details are entered into the username/password fields. Any suggestions really appreciated - I'm at a loss.

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  • How would you code an efficient Circular Buffer in Java or C#

    - by Cheeso
    I want a simple class that implements a fixed-size circular buffer. It should be efficient, easy on the eyes, generically typed. EDIT: It need not be MT-capable, for now. I can always add a lock later, it won't be high-concurrency in any case. Methods should be: .Add and I guess .List, where I retrieve all the entries. On second thought, Retrieval I think should be done via an indexer. At any moment I will want to be able to retrieve any element in the buffer by index. But keep in mind that from one moment to the next Element[n] may be different, as the Circular buffer fills up and rolls over. This isn't a stack, it's a circular buffer. Regarding "overflow": I would expect internally there would be an array holding the items, and over time the head and tail of the buffer will rotate around that fixed array. But that should be invisible from the user. There should be no externally-detectable "overflow" event or behavior. This is not a school assignment - it is most commonly going to be used for a MRU cache or a fixed-size transaction or event log.

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  • Conditional row count in linq to nhibernate doesn't work

    - by Lucasus
    I want to translate following simple sql query into Linq to NHibernate: SELECT NewsId ,sum(n.UserHits) as 'HitsNumber' ,sum(CASE WHEN n.UserHits > 0 THEN 1 ELSE 0 END) as 'VisitorsNumber' FROM UserNews n GROUP BY n.NewsId My simplified UserNews class: public class AktualnosciUzytkownik { public virtual int UserNewsId { get; set; } public virtual int UserHits { get; set; } public virtual User User { get; set; } // UserId key in db table public virtual News News { get; set; } // NewsId key in db table } I've written following linq query: var hitsPerNews = (from n in Session.Query<UserNews>() group n by n.News.NewsId into g select new { NewsId = g.Key, HitsNumber = g.Sum(x => x.UserHits), VisitorsNumber = g.Count(x => x.UserHits > 0) }).ToList(); But generated sql just ignores my x => x.UserHits > 0 statement and makes unnecessary 'left outer join': SELECT news1_.NewsId AS col_0_0_, CAST(SUM(news0_.UserHits) AS INT) AS col_1_0_, CAST(COUNT(*) AS INT) AS col_2_0_ FROM UserNews news0_ LEFT OUTER JOIN News news1_ ON news0_.NewsId=news1_.NewsId GROUP BY news1_.NewsId How Can I fix or workaround this issue? Maybe this can be done better with QueryOver syntax?

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  • What algorithm can I use to determine points within a semi-circle?

    - by khayman218
    I have a list of two-dimensional points and I want to obtain which of them fall within a semi-circle. Originally, the target shape was a rectangle aligned with the x and y axis. So the current algorithm sorts the pairs by their X coord and binary searches to the first one that could fall within the rectangle. Then it iterates over each point sequentially. It stops when it hits one that is beyond both the X and Y upper-bound of the target rectangle. This does not work for a semi-circle as you cannot determine an effective upper/lower x and y bounds for it. The semi-circle can have any orientation. Worst case, I will find the least value of a dimension (say x) in the semi-circle, binary search to the first point which is beyond it and then sequentially test the points until I get beyond the upper bound of that dimension. Basically testing an entire band's worth of points on the grid. The problem being this will end up checking many points which are not within the bounds.

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  • Google Analytics version 3 - How to apply it correctly?

    - by ephramd
    I've added google analytics to my app with the intention of obtaining information about the screens you and send custom events. I am obtained duplicate content ... Also I get different results: "com.package.app.MainScreen" - 300 views and "Main Screen" - 200 views I am interested to get only follow up with the custom name of the activity and not the package. And in any case, because both show different results? public class MainScreen extends Activity { private static final String GA_PROPERTY_ID = "UA-12345678-9"; private static final String SCREEN_LABEL = "Main Screen"; Tracker mTracker; EasyTracker easyTracker; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main_screen); mTracker = GoogleAnalytics.getInstance(this).getTracker(GA_PROPERTY_ID); mTracker.set(Fields.SCREEN_NAME, SCREEN_LABEL); // For Custom Name from activity mTracker.send(MapBuilder.createAppView().build()); easyTracker = EasyTracker.getInstance(this); // Analytics Events ... easyTracker.send(MapBuilder.createEvent("MainScreen", "Play", category.get(1), null).build()); //AnalyticsEvents ... } @Override public void onStart() { super.onStart(); EasyTracker.getInstance(this).activityStart(this); } @Override public void onStop() { super.onStop(); EasyTracker.getInstance(this).activityStop(this); } } And analytics.xml: <?xml version="1.0" encoding="utf-8" ?> <resources xmlns:tools="http://schemas.android.com/tools" tools:ignore="TypographyDashes"> <!--Replace placeholder ID with your tracking ID--> <string name="ga_trackingId">UA-12345678-9</string> <!--Enable automatic activity tracking--> <bool name="ga_autoActivityTracking">true</bool> <!--Enable automatic exception tracking--> <bool name="ga_reportUncaughtExceptions">true</bool> </resources> Google Analytics Dev Guide

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  • Retrieving ids from MySQL query

    - by Matt Maclennan
    I am having trouble accessing the "model_id" and "brand_id" from the foreach loop that I am using. They are the right field names, because I have echoed them successfully, and I have also "var_dumped" the array, and the IDs are there. It is just a case of implementing the relevant links on each list section. Below is the code I have. <? $output = mysqli_query("SELECT * FROM bikes, bikeTypes WHERE bikes.model_id = bikeTypes.model_id"); $result = array(); while($row = mysqli_fetch_array($output)) { $result[$row['model']][] = $row; } foreach ($result as $category => $values) { echo "<li><a href='test.php?id=" . $row['model_id'] . "'>".$category.'</a><ul>'; foreach ($values as $value) { echo "<li><a href='details.php?id=" . $row['brand_id'] . "'>" . $value['bikeName'] . "</a></li>"; } echo '</ul>'; echo '</li>'; } ?>

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  • Java - How to find the redirected url of a url?

    - by Yatendra Goel
    I am accessing web pages through java as follows: URLConnection con = url.openConnection(); But in some cases, a url redirects to another url. So I want to know the url to which the previous url redirected. Below are the header fields that I got as a response: null-->[HTTP/1.1 200 OK] Cache-control-->[public,max-age=3600] last-modified-->[Sat, 17 Apr 2010 13:45:35 GMT] Transfer-Encoding-->[chunked] Date-->[Sat, 17 Apr 2010 13:45:35 GMT] Vary-->[Accept-Encoding] Expires-->[Sat, 17 Apr 2010 14:45:35 GMT] Set-Cookie-->[cl_def_hp=copenhagen; domain=.craigslist.org; path=/; expires=Sun, 17 Apr 2011 13:45:35 GMT, cl_def_lang=en; domain=.craigslist.org; path=/; expires=Sun, 17 Apr 2011 13:45:35 GMT] Connection-->[close] Content-Type-->[text/html; charset=iso-8859-1;] Server-->[Apache] So at present, I am constructing the redirected url from the value of the Set-Cookie header field. In the above case, the redirected url is copenhagen.craigslist.org Is there any standard way through which I can determine which url the particular url is going to redirect. I know that when a url redirects to other url, the server sends an intermediate response containing a header field that tells the url which it is going to redirect but I am not receiving that intermediate response through the url.openConnection(); method.

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  • Spring MVC: How to get the remaining path after the controller path?

    - by Willis Blackburn
    I've spent over an hour trying to find the answer to this question, which seems like it should reflect a common use case, but I can't figure it out! Basically I am writing a file-serving controller using Spring MVC. The URLs are of the format http://www.bighost.com/serve/the/path/to/the/file.jpg, in which the part after "/serve" is the path to the requested file, which may have an arbitrary number of path segments. I have a controller like this: @Controller class ServerController { @RequestMapping(value = "/serve/???") public void serve(???) { } } What I am trying to figure out is: What do I use in place of "???" to make this work? I have two theories about how this should work. The first theory is that I could replace the first "???" in the RequestMapping with a path variable placeholder that has some special syntax meaning "capture to the end of the path." If a regular placeholder looks like "{path}" then maybe I could use "{path:**}" or "{path:/}" or something like that. Then I could use a @PathVariable annotation to refer to the path variable in the second "???". The other theory is that I could replace the first "???" with "**" (match anything) and that Spring would give me an API to obtain the remainder of the path (the part matching the "**"). But I can't find such an API. Thanks for any help you can provide!

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  • Java Executor: Small tasks or big ones?

    - by Arash Shahkar
    Consider one big task which could be broken into hundreds of small, independently-runnable tasks. To be more specific, each small task is to send a light network request and decide upon the answer received from the server. These small tasks are not expected to take longer than a second, and involve a few servers in total. I have in mind two approaches to implement this using the Executor framework, and I want to know which one's better and why. Create a few, say 5 to 10 tasks each involving doing a bunch of send and receives. Create a single task (Callable or Runnable) for each send & receive and schedule all of them (hundreds) to be run by the executor. I'm sorry if my question shows that I'm lazy to test these and see for myself what's better (at least performance-wise). My question, while looking after an answer to this specific case, has a more general aspect. In situations like these when you want to use an executor to do all the scheduling and other stuff, is it better to create lots of small tasks or to group those into a less number of bigger tasks?

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  • Obtaining FontMetrics before getting a Graphics instance

    - by Tom Castle
    Typically, I'd obtain a graphics instance something like this: BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB); Graphics2D g = img.createGraphics(); However, in the current project I'm working on, the width and height variables above are dependent upon the size of a number of text fragments that will later be drawn onto the graphics instance. But, to obtain the dimensions of the font being used I would usually use the FontMetrics that I get from the graphics object. FontMetrics metrics = g.getFontMetrics(); So, I have a nasty little dependency cycle. I cannot create the graphics object until I know the size of the text, and I cannot know the size of the text until I have a graphics object. One solution is just to create another BufferedImage/Graphics pair first in order to get the FontMetrics instance I need, but this seems unnecessary. So, is there a nicer way? Or is it the case that the width, height etc. properties for a Font are somehow dependent upon what (graphics, component...) the text is to be drawn on?

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  • Java abstract visitor - guarantueed to succeed? If so, why?

    - by disown
    I was dealing with hibernate, trying to figure out the run-time class behind proxied instances by using the visitor pattern. I then came up with an AbstractVisitable approach, but I wonder if it will always produce correct results. Consider the following code: interface Visitable { public void accept(Visitor v); } interface Visitor { public void visit(Visitable visitorHost); } abstract class AbstractVisitable implements Visitable { @Override public void accept(Visitor v) { v.visit(this); } } class ConcreteVisitable extends AbstractVisitable { public static void main(String[] args) { final Visitable visitable = new ConcreteVisitable(); final Visitable proxyVisitable = (Visitable) Proxy.newProxyInstance( Thread.currentThread().getContextClassLoader(), new Class<?>[] { Visitable.class }, new InvocationHandler() { @Override public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { return method.invoke(visitable, args); } }); proxyVisitable.accept(new Visitor() { @Override public void visit(Visitable visitorHost) { System.out.println(visitorHost.getClass()); } }); } } This makes a ConcreteVisitable which inherits the accept method from AbstractVisitable. In c++, I would consider this risky, since this in AbstractVisitable could be referencing to AbstractVisitable::this, and not ConcreteVisitable::this. I was worried that the code under certain circumstances would print class AbstractVisible. Yet the code above outputs class ConcreteVisitable, even though I hid the real type behind a dynamic proxy (the most difficult case I could come up with). Is the abstract visitor approach above guaranteed to work, or are there some pitfalls with this approach? What guarantees are given in Java with respect to the this pointer?

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  • Binding value for NSTableView, but tooltip gets set as well

    - by Mark
    I've set up an NSTableView in Interface Builder to be populated from an NSArray. Each value of the array represents one row in the table. The value is bound correctly, but as a side effect, the table cell's tooltip is set to the string representation of the bound object. In my case, the NSArray contains NSDictiorany objects and the tooltip looks like it could be the [... description] output of that dictionary. Very ugly... I don't want the tooltip to be set at all. I have other tables that have plain NSString values bound to them and they don't have a tooltip set automatically. Is there some Interface Builder magic going on? I tried to start with a blank project - same problem. I should add that the table cell is a custom implementation of NSTextFieldCell that uses an NSButtonCell instance to draw an image and a label into the table. The values are retrieved from the dictionary bound as value. Why is the tooltip set when I only bind the "value" attribute? Thanks in advance!

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  • Is Assert.Fail() considered bad practice?

    - by Mendelt
    I use Assert.Fail a lot when doing TDD. I'm usually working on one test at a time but when I get ideas for things I want to implement later I quickly write an empty test where the name of the test method indicates what I want to implement as sort of a todo-list. To make sure I don't forget I put an Assert.Fail() in the body. When trying out xUnit.Net I found they hadn't implemented Assert.Fail. Of course you can always Assert.IsTrue(false) but this doesn't communicate my intention as well. I got the impression Assert.Fail wasn't implemented on purpose. Is this considered bad practice? If so why? @Martin Meredith That's not exactly what I do. I do write a test first and then implement code to make it work. Usually I think of several tests at once. Or I think about a test to write when I'm working on something else. That's when I write an empty failing test to remember. By the time I get to writing the test I neatly work test-first. @Jimmeh That looks like a good idea. Ignored tests don't fail but they still show up in a separate list. Have to try that out. @Matt Howells Great Idea. NotImplementedException communicates intention better than assert.Fail() in this case @Mitch Wheat That's what I was looking for. It seems it was left out to prevent it being abused in another way I abuse it.

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  • Create a real time web application using .net framework and azure - very confused

    - by test
    Let us say I would like a simple (yet complex) web application where there is continuous READING AND WRITING to the sql azure database. Let us say I am tracking a location, and I would like it to be updated very frequently (lets take the worst case: 1 second). From the little knowledge I have, I think that this involves the use of the database to continuously write the location to the database, and continuously read from the database to update another person through a website. Do you please have any suggestion which technologies can I use? Is there a simple way? I heard about node.js, signalR. I have no idea how to use them, if they are really what I need. the last tutorial I checked out simply uses a while(true) loop..but I don't think that that's something good to keep a thread continuously busy... Do I have to create some background task? Do I have to create some web service? This is a school project and I wish not to go for the most difficult option, but if there is some sort of solution, challenge accepted :) Can you please help me? Since I have asked many questions here and yet I have no solution in mind

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