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  • undefined reference to `main' collect2: ld returned 1 exit status

    - by sobingt
    I am working on this QT project and i am making test cases for my project. Here is a small test case #include <QApplication> #include <QPalette> #include <QPixmap> #include <QSplashScreen> #include <qthread.h> #define BOOST_TEST_MAIN #include <boost/test/unit_test.hpp> #include <boost/make_shared.hpp> # include <boost/thread.hpp> #include "MainWindow.h" namespace { const std::string dbname = "Project.db"; struct SongFixture { SongFixture(const std::string &fixturePath) { // Create the Master file Master::creator(); // Create/open file std::pair<int, SQLiteDbPtr> result = open( dbname, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0); if (result.first != SQLITE_OK) { throw SQLiteError(result.first, sqlite3_errmsg(result.second.get())); } SQLiteDbPtr &spDb = result.second; // Execute all the SQL from the fixture file execSQLFromFile(spDb, fixturePath); } }; std::auto_ptr<SongFixture> pf; } class I : public QThread { public: static void sleep(unsigned long secs) { QThread::sleep(secs); } }; void free_test_function() { BOOST_CHECK(true ); } test_suite* init_unit_test_suite(int argc, char *argv[]) { // Create a fixture for the peer: // Manage fixture creation manually instead of using // BOOST_FIXTURE_TEST_CASE because the fixture depends on runtime args. std::ostringstream fixturePathSS; fixturePathSS << PROJECT_DIR << "/test/songs_fixture.sql"; std::string fixturePath = fixturePathSS.str(); pf.reset(new SongFixture(fixturePath)); QApplication app(argc, argv); MainWindow window("artists"); window.show(); framework::master_test_suite().add( BOOST_TEST_CASE( &free_test_function )); return app.exec(); } Well i am getting any error /usr/lib/gcc/x86_64-linux-gnu/4.6.1/../../../x86_64-linux-gnu/crt1.o: In function _start': (.text+0x20): undefined reference tomain' collect2: ld returned 1 exit status pls help me you have a lead..thankz I tired adding #define BOOST_TEST_MAIN then i get ../test/UI/main.cpp: In function ‘boost::unit_test::test_suite* init_unit_test_suite(int, char**)’: ../test/UI/main.cpp:75:31: error: redefinition of ‘boost::unit_test::test_suite* init_unit_test_suite(int, char**)’ /usr/local/include/boost/test/unit_test_suite.hpp:223:1: error: ‘boost::unit_test::test_suite* init_unit_test_suite(int, char**)’ previously defined here Well the program is working in Windows but in Linux the above mention problem is observed

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  • UML assignment question

    - by waitinforatrain
    Hi guys, Sorry, I know this is a very lame question to ask and not of any use to anyone else. I have an assignment in UML due tomorrow and I don't even know the basics (all-nighter ahead!). I'm not looking for a walkthrough, I simply want your opinion on something. The assignment is as follows (you only need to skim over it!): ============= Gourmet Surprise (GS) is a small catering firm with five employees. During a typical weekend, GS caters fifteen events with twenty to fifty people each. The business has grown rapidly over the past year and the owner wants to install a new computer system for managing the ordering and buying process. GS has a set of ten standard menus. When potential customers call, the receptionist describes the menus to them. If the customer decides to book an event (dinner, lunch, picnic, finger food etc.), the receptionist records the customer information (e.g., name, address, phone number, etc.) and the information about the event (e.g., place, date, time, which one of the standard menus, total price) on a contract. The customer is then faxed a copy of the contract and must sign and return it along with a deposit (often a credit card or by check) before the event is officially booked. The remaining money is collected when the catering is delivered. Sometimes, the customer wants something special (e.g., birthday cake). In this case, the receptionist takes the information and gives it to the owner who determines the cost; the receptionist then calls the customer back with the price information. Sometimes the customer accepts the price, other times, the customer requests some changes that have to go back to the owner for a new cost estimate. Each week, the owner looks through the events scheduled for that weekend and orders the supplies (e.g., plates) and food (e.g., bread, chicken) needed to make them. The owner would like to use the system for marketing as well. It should be able to track how customers learned about GS, and identify repeat customers, so that GS can mail special offers to them. The owner also wants to track the events on which GS sent a contract, but the customer never signed the contract and actually booked a GS. Exercise: Create an activity diagram and a use case model (complete with a set of detail use case descriptions) for the above system. Produce an initial domain model (class diagram) based on these descriptions. Elaborate the use cases into sequence diagrams, and include any state diagrams necessary. Finally use the information from these dynamic models to expand the domain model into a full application model. ============= In your opinion, do you think this question is asking me to come up with a package for an online ordering system to replace the system described above, or to create UML diagrams that facilitate the existing telephone-based system?

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  • Databinding to ObservableCollection in a different UserControl?

    - by Dave
    Question re-written on 2010-03-24 I have two UserControls, where one is a dialog that has a TabControl, and the other is one that appears within said TabControl. I'll just call them CandyDialog and CandyNameViewer for simplicity's sake. There's also a data management class called Tracker that manages information storage, which for all intents and purposes just exposes a public property that is an ObservableCollection. I display the CandyNameViewer in CandyDialog via code behind, like this: private void CandyDialog_Loaded( object sender, RoutedEventArgs e) { _candyviewer = new CandyViewer(); _candyviewer.DataContext = _tracker; candy_tab.Content = _candyviewer; } The CandyViewer's XAML looks like this (edited for kaxaml): <Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"> <Page.Resources> <DataTemplate x:Key="CandyItemTemplate"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="120"></ColumnDefinition> <ColumnDefinition Width="150"></ColumnDefinition> </Grid.ColumnDefinitions> <TextBox Grid.Column="0" Text="{Binding CandyName}" Margin="3"></TextBox> <!-- just binding to DataContext ends up using InventoryItem as parent, so we need to get to the UserControl --> <ComboBox Grid.Column="1" SelectedItem="{Binding SelectedCandy, Mode=TwoWay}" ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.CandyNames}" Margin="3"></ComboBox> </Grid> </DataTemplate> </Page.Resources> <Grid> <ListBox DockPanel.Dock="Top" ItemsSource="{Binding CandyBoxContents, Mode=TwoWay}" ItemTemplate="{StaticResource CandyItemTemplate}" /> </Grid> </Page> Now everything works fine when the controls are loaded. As long as CandyNames is populated first, and then the consumer UserControl is displayed, all of the names are there. I obviously don't get any errors in the Output Window or anything like that. The issue I have is that when the ObservableCollection is modified from the model, those changes are not reflected in the consumer UserControl! I've never had this problem before; all of my previous uses of ObservableCollection updated fine, although in those cases I wasn't databinding across assemblies. Although I am currently only adding and removing candy names to/from the ObservableCollection, at a later date I will likely also allow renaming from the model side. Is there something I did wrong? Is there a good way to actually debug this? Reed Copsey indicates here that inter-UserControl databinding is possible. Unfortunately, my favorite Bea Stollnitz article on WPF databinding debugging doesn't suggest anything that I could use for this particular problem.

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  • How to troubleshoot a 'System.Management.Automation.CmdletInvocationException'

    - by JamesD
    Does anyone know how best to determine the specific underlying cause of this exception? Consider a WCF service that is supposed to use Powershell 2.0 remoting to execute MSBuild on remote machines. In both cases the scripting environments are being called in-process (via C# for Powershell and via Powershell for MSBuild), rather than 'shelling-out' - this was a specific design decision to avoid command-line hell as well as to enable passing actual objects into the Powershell script. The Powershell script that calls MSBuild is shown below: function Run-MSBuild { [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.Build.Engine") $engine = New-Object Microsoft.Build.BuildEngine.Engine $engine.BinPath = "C:\Windows\Microsoft.NET\Framework\v3.5" $project = New-Object Microsoft.Build.BuildEngine.Project($engine, "3.5") $project.Load("deploy.targets") $project.InitialTargets = "DoStuff" # # Set some initial Properties & Items # # Optionally setup some loggers (have also tried it without any loggers) $consoleLogger = New-Object Microsoft.Build.BuildEngine.ConsoleLogger $engine.RegisterLogger($consoleLogger) $fileLogger = New-Object Microsoft.Build.BuildEngine.FileLogger $fileLogger.Parameters = "verbosity=diagnostic" $engine.RegisterLogger($fileLogger) # Run the build - this is the line that throws a CmdletInvocationException $result = $project.Build() $engine.Shutdown() } When running the above script from a PS command prompt it all works fine. However, as soon as the script is executed from C# it fails with the above exception. The C# code being used to call Powershell is shown below (remoting functionality removed for simplicity's sake): // Build the DTO object that will be passed to Powershell dto = SetupDTO() RunspaceConfiguration runspaceConfig = RunspaceConfiguration.Create(); using (Runspace runspace = RunspaceFactory.CreateRunspace(runspaceConfig)) { runspace.Open(); IList errors; using (var scriptInvoker = new RunspaceInvoke(runspace)) { // The Powershell script lives in a file that gets compiled as an embedded resource TextReader tr = new StreamReader(Assembly.GetExecutingAssembly().GetManifestResourceStream("MyScriptResource")); string script = tr.ReadToEnd(); // Load the script into the Runspace scriptInvoker.Invoke(script); // Call the function defined in the script, passing the DTO as an input object var psResults = scriptInvoker.Invoke("$input | Run-MSBuild", dto, out errors); } } Assuming that the issue was related to MSBuild outputting something that the Powershell runspace can't cope with, I have also tried the following variations to the second .Invoke() call: var psResults = scriptInvoker.Invoke("$input | Run-MSBuild | Out-String", dto, out errors); var psResults = scriptInvoker.Invoke("$input | Run-MSBuild | Out-Null", dto, out errors); var psResults = scriptInvoker.Invoke("Run-MSBuild | Out-String"); var psResults = scriptInvoker.Invoke("Run-MSBuild | Out-String"); var psResults = scriptInvoker.Invoke("Run-MSBuild | Out-Null"); I've also looked at using a custom PSHost (based on this sample: http://blogs.msdn.com/daiken/archive/2007/06/22/hosting-windows-powershell-sample-code.aspx), but during debugging I was unable to see any 'interesting' calls to it being made. Do the great and the good of Stackoverflow have any insight that might save my sanity?

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  • Eventlet or gevent or Stackless + Twisted, Pylons, Django and SQL Alchemy

    - by Khorkrak
    We're using Twisted extensively for apps requiring a great deal of asynchronous io. There are some cases where stuff is cpu bound instead and for that we spawn a pool of processes to do the work and have a system for managing these across multiple servers as well - all done in Twisted. Works great. The problem is that it's hard to bring new team members up to speed. Writing asynchronous code in Twisted requires a near vertical learning curve. It's as if humans just don't think that way naturally. We're considering a mixed approach perhaps. Maybe do the xmlrpc server part and process management in Twisted still but the other stuff in code that at least looks synchronous while not being as such. Then again I like explicit over implicit so hmmm. Anyway onto greenlets - how well does that stuff work? So there's Stackless and as you can see from my Gallentean avatar I'm well aware of the tremendous success in it's use for CCP's flagship EVE Online game first hand. What about Eventlet or gevent? Well for now only Eventlet works with Twisted. However gevent claims to be faster since it's not a pure python implementation it instead uses libevent. It also has fewer idiosyncrasies and defects supposedly. The documentation there is minimal in comparison to Eventlet and it's maintained by 1 guy as far as I can tell. This makes me leery but all great projects start this way so... Then there's PyPy - I haven't even finished reading about that one yet - just saw it in this thread: Drawbacks of Stackless. So confusing - I'm wondering what the heck to do - sounds like Eventlet is probably the best bet but is it really stable enough? Anyone out there have any experience with it? Should we go with Stackless instead as it's been around and is proven technology - just like Twisted is as well - and they do work together nicely. But still I hate having to have a separate version of Python to do this. what to do.... This somewhat obnoxious blog entry hit the nail on the head for me though: Asynchronous IO for Grownups We're stuck using MySQL as well - I never knew how great PostgreSQL was until having had to work on a production OLTP system in MySQL instead - but that's another story. But if that monkey patch thing really works then wow. Just wow.

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  • Why is code quality not popular?

    - by Peter Kofler
    I like my code being in order, i.e. properly formatted, readable, designed, tested, checked for bugs, etc. In fact I am fanatic about it. (Maybe even more than fanatic...) But in my experience actions helping code quality are hardly implemented. (By code quality I mean the quality of the code you produce day to day. The whole topic of software quality with development processes and such is much broader and not the scope of this question.) Code quality does not seem popular. Some examples from my experience include Probably every Java developer knows JUnit, almost all languages implement xUnit frameworks, but in all companies I know, only very few proper unit tests existed (if at all). I know that it's not always possible to write unit tests due to technical limitations or pressing deadlines, but in the cases I saw, unit testing would have been an option. If a developer wanted to write some tests for his/her new code, he/she could do so. My conclusion is that developers do not want to write tests. Static code analysis is often played around in small projects, but not really used to enforce coding conventions or find possible errors in enterprise projects. Usually even compiler warnings like potential null pointer access are ignored. Conference speakers and magazines would talk a lot about EJB3.1, OSGI, Cloud and other new technologies, but hardly about new testing technologies or tools, new static code analysis approaches (e.g. SAT solving), development processes helping to maintain higher quality, how some nasty beast of legacy code was brought under test, ... (I did not attend many conferences and it propably looks different for conferences on agile topics, as unit testing and CI and such has a higer value there.) So why is code quality so unpopular/considered boring? EDIT: Thank your for your answers. Most of them concern unit testing (and has been discussed in a related question). But there are lots of other things that can be used to keep code quality high (see related question). Even if you are not able to use unit tests, you could use a daily build, add some static code analysis to your IDE or development process, try pair programming or enforce reviews of critical code.

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  • IE7 relative/absolute positioning bug with dynamically modified page content

    - by Matthias Hryniszak
    Hi, I was wondering if there's anyone having an idea how to tackle with the following problem in IE7: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>IE7 absolute positioning bug</title> <style type="text/css"> #panel { position: relative; border: solid 1px black; } #spacer { height: 100px; } #footer { position: absolute; bottom: 0px; } </style> <script type="text/javascript"> function toggle() { var spacer = document.getElementById("spacer"); var style = "block"; if (spacer.style.display == "block" || spacer.style.display == "") { style = "none"; } spacer.style.display = style; } </script> </head> <body> <div id="panel"> <button onclick="toggle();">Click me</button> <br /><br /><br /> <div id="spacer"></div> <div id="footer">This is some footer</div> </div> </body> </html> When you run this in IE7 you'll see that the "footer" element stays after modifying the CSS for "panel". The same example tested in IE8, FF and Chrome behaves exactly as expected. I've already tried updating the element's class but this does not work if the browser's window has been opened maximized and no further size changes were made to the window (which is about 90% of the use cases we have for our product.... :( ) I'm stuck with a CSS-based solution however I think that I can make an exception in this case if it can easily be made IE7-specific (which means that other browsers will behave in a standard way with this). Please help!

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  • General advice and guidelines on how to properly override object.GetHashCode()

    - by Svish
    According to MSDN, a hash function must have the following properties: If two objects compare as equal, the GetHashCode method for each object must return the same value. However, if two objects do not compare as equal, the GetHashCode methods for the two object do not have to return different values. The GetHashCode method for an object must consistently return the same hash code as long as there is no modification to the object state that determines the return value of the object's Equals method. Note that this is true only for the current execution of an application, and that a different hash code can be returned if the application is run again. For the best performance, a hash function must generate a random distribution for all input. I keep finding myself in the following scenario: I have created a class, implemented IEquatable<T> and overridden object.Equals(object). MSDN states that: Types that override Equals must also override GetHashCode ; otherwise, Hashtable might not work correctly. And then it usually stops up a bit for me. Because, how do you properly override object.GetHashCode()? Never really know where to start, and it seems to be a lot of pitfalls. Here at StackOverflow, there are quite a few questions related to GetHashCode overriding, but most of them seems to be on quite particular cases and specific issues. So, therefore I would like to get a good compilation here. An overview with general advice and guidelines. What to do, what not to do, common pitfalls, where to start, etc. I would like it to be especially directed at C#, but I would think it will work kind of the same way for other .NET languages as well(?). I think maybe the best way is to create one answer per topic with a quick and short answer first (close to one-liner if at all possible), then maybe some more information and end with related questions, discussions, blog posts, etc., if there are any. I can then create one post as the accepted answer (to get it on top) with just a "table of contents". Try to keep it short and concise. And don't just link to other questions and blog posts. Try to take the essence of them and then rather link to source (especially since the source could disappear. Also, please try to edit and improve answers instead of created lots of very similar ones. I am not a very good technical writer, but I will at least try to format answers so they look alike, create the table of contents, etc. I will also try to search up some of the related questions here at SO that answers parts of these and maybe pull out the essence of the ones I can manage. But since I am not very stable on this topic, I will try to stay away for the most part :p

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  • Which functions in the C standard library commonly encourage bad practice?

    - by Ninefingers
    Hello all, This is inspired by this question and the comments on one particular answer in that I learnt that strncpy is not a very safe string handling function in C and that it pads zeros, until it reaches n, something I was unaware of. Specifically, to quote R.. strncpy does not null-terminate, and does null-pad the whole remainder of the destination buffer, which is a huge waste of time. You can work around the former by adding your own null padding, but not the latter. It was never intended for use as a "safe string handling" function, but for working with fixed-size fields in Unix directory tables and database files. snprintf(dest, n, "%s", src) is the only correct "safe strcpy" in standard C, but it's likely to be a lot slower. By the way, truncation in itself can be a major bug and in some cases might lead to privilege elevation or DoS, so throwing "safe" string functions that truncate their output at a problem is not a way to make it "safe" or "secure". Instead, you should ensure that the destination buffer is the right size and simply use strcpy (or better yet, memcpy if you already know the source string length). And from Jonathan Leffler Note that strncat() is even more confusing in its interface than strncpy() - what exactly is that length argument, again? It isn't what you'd expect based on what you supply strncpy() etc - so it is more error prone even than strncpy(). For copying strings around, I'm increasingly of the opinion that there is a strong argument that you only need memmove() because you always know all the sizes ahead of time and make sure there's enough space ahead of time. Use memmove() in preference to any of strcpy(), strcat(), strncpy(), strncat(), memcpy(). So, I'm clearly a little rusty on the C standard library. Therefore, I'd like to pose the question: What C standard library functions are used inappropriately/in ways that may cause/lead to security problems/code defects/inefficiencies? In the interests of objectivity, I have a number of criteria for an answer: Please, if you can, cite design reasons behind the function in question i.e. its intended purpose. Please highlight the misuse to which the code is currently put. Please state why that misuse may lead towards a problem. I know that should be obvious but it prevents soft answers. Please avoid: Debates over naming conventions of functions (except where this unequivocably causes confusion). "I prefer x over y" - preference is ok, we all have them but I'm interested in actual unexpected side effects and how to guard against them. As this is likely to be considered subjective and has no definite answer I'm flagging for community wiki straight away. I am also working as per C99.

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  • Synchronized Enumerator in C#

    - by Dan Bryant
    I'm putting together a custom SynchronizedCollection<T> class so that I can have a synchronized Observable collection for my WPF application. The synchronization is provided via a ReaderWriterLockSlim, which, for the most part, has been easy to apply. The case I'm having trouble with is how to provide thread-safe enumeration of the collection. I've created a custom IEnumerator<T> nested class that looks like this: private class SynchronizedEnumerator : IEnumerator<T> { private SynchronizedCollection<T> _collection; private int _currentIndex; internal SynchronizedEnumerator(SynchronizedCollection<T> collection) { _collection = collection; _collection._lock.EnterReadLock(); _currentIndex = -1; } #region IEnumerator<T> Members public T Current { get; private set;} #endregion #region IDisposable Members public void Dispose() { var collection = _collection; if (collection != null) collection._lock.ExitReadLock(); _collection = null; } #endregion #region IEnumerator Members object System.Collections.IEnumerator.Current { get { return Current; } } public bool MoveNext() { var collection = _collection; if (collection == null) throw new ObjectDisposedException("SynchronizedEnumerator"); _currentIndex++; if (_currentIndex >= collection.Count) { Current = default(T); return false; } Current = collection[_currentIndex]; return true; } public void Reset() { if (_collection == null) throw new ObjectDisposedException("SynchronizedEnumerator"); _currentIndex = -1; Current = default(T); } #endregion } My concern, however, is that if the Enumerator is not Disposed, the lock will never be released. In most use cases, this is not a problem, as foreach should properly call Dispose. It could be a problem, however, if a consumer retrieves an explicit Enumerator instance. Is my only option to document the class with a caveat implementer reminding the consumer to call Dispose if using the Enumerator explicitly or is there a way to safely release the lock during finalization? I'm thinking not, since the finalizer doesn't even run on the same thread, but I was curious if there other ways to improve this.

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  • Python - calculate multinomial probability density functions on large dataset?

    - by Seafoid
    Hi, I originally intended to use MATLAB to tackle this problem but the inbuilt functions has limitations that do not suit my goal. The same limitation occurs in NumPy. I have two tab-delimited files. The first is a file showing amino acid residue, frequency and count for an in-house database of protein structures, i.e. A 0.25 1 S 0.25 1 T 0.25 1 P 0.25 1 The second file consists of quadruplets of amino acids and the number of times they occur, i.e. ASTP 1 Note, there are 8,000 such quadruplets. Based on the background frequency of occurence of each amino acid and the count of quadruplets, I aim to calculate the multinomial probability density function for each quadruplet and subsequently use it as the expected value in a maximum likelihood calculation. The multinomial distribution is as follows: f(x|n, p) = n!/(x1!*x2!*...*xk!)*((p1^x1)*(p2^x2)*...*(pk^xk)) where x is the number of each of k outcomes in n trials with fixed probabilities p. n is 4 four in all cases in my calculation. I have created three functions to calculate this distribution. # functions for multinomial distribution def expected_quadruplets(x, y): expected = x*y return expected # calculates the probabilities of occurence raised to the number of occurrences def prod_prob(p1, a, p2, b, p3, c, p4, d): prob_prod = (pow(p1, a))*(pow(p2, b))*(pow(p3, c))*(pow(p4, d)) return prob_prod # factorial() and multinomial_coefficient() work in tandem to calculate C, the multinomial coefficient def factorial(n): if n <= 1: return 1 return n*factorial(n-1) def multinomial_coefficient(a, b, c, d): n = 24.0 multi_coeff = (n/(factorial(a) * factorial(b) * factorial(c) * factorial(d))) return multi_coeff The problem is how best to structure the data in order to tackle the calculation most efficiently, in a manner that I can read (you guys write some cryptic code :-)) and that will not create an overflow or runtime error. To data my data is represented as nested lists. amino_acids = [['A', '0.25', '1'], ['S', '0.25', '1'], ['T', '0.25', '1'], ['P', '0.25', '1']] quadruplets = [['ASTP', '1']] I initially intended calling these functions within a nested for loop but this resulted in runtime errors or overfloe errors. I know that I can reset the recursion limit but I would rather do this more elegantly. I had the following: for i in quadruplets: quad = i[0].split(' ') for j in amino_acids: for k in quadruplets: for v in k: if j[0] == v: multinomial_coefficient(int(j[2]), int(j[2]), int(j[2]), int(j[2])) I haven'te really gotten to how to incorporate the other functions yet. I think that my current nested list arrangement is sub optimal. I wish to compare the each letter within the string 'ASTP' with the first component of each sub list in amino_acids. Where a match exists, I wish to pass the appropriate numeric values to the functions using indices. Is their a better way? Can I append the appropriate numbers for each amino acid and quadruplet to a temporary data structure within a loop, pass this to the functions and clear it for the next iteration? Thanks, S :-)

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  • Any significant performance improvement by using bitwise operators instead of plain int sums in C#?

    - by tunnuz
    Hello, I started working with C# a few weeks ago and I'm now in a situation where I need to build up a "bit set" flag to handle different cases in an algorithm. I have thus two options: enum RelativePositioning { LEFT = 0, RIGHT = 1, BOTTOM = 2, TOP = 3, FRONT = 4, BACK = 5 } pos = ((eye.X < minCorner.X ? 1 : 0) << RelativePositioning.LEFT) + ((eye.X > maxCorner.X ? 1 : 0) << RelativePositioning.RIGHT) + ((eye.Y < minCorner.Y ? 1 : 0) << RelativePositioning.BOTTOM) + ((eye.Y > maxCorner.Y ? 1 : 0) << RelativePositioning.TOP) + ((eye.Z < minCorner.Z ? 1 : 0) << RelativePositioning.FRONT) + ((eye.Z > maxCorner.Z ? 1 : 0) << RelativePositioning.BACK); Or: enum RelativePositioning { LEFT = 1, RIGHT = 2, BOTTOM = 4, TOP = 8, FRONT = 16, BACK = 32 } if (eye.X < minCorner.X) { pos += RelativePositioning.LEFT; } if (eye.X > maxCorner.X) { pos += RelativePositioning.RIGHT; } if (eye.Y < minCorner.Y) { pos += RelativePositioning.BOTTOM; } if (eye.Y > maxCorner.Y) { pos += RelativePositioning.TOP; } if (eye.Z > maxCorner.Z) { pos += RelativePositioning.FRONT; } if (eye.Z < minCorner.Z) { pos += RelativePositioning.BACK; } I could have used something as ((eye.X > maxCorner.X) << 1) but C# does not allow implicit casting from bool to int and the ternary operator was similar enough. My question now is: is there any performance improvement in using the first version over the second? Thank you Tommaso

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  • iPhone UIWebView: loadData does not work with certain types (Excel, MSWord, PPT, RTF)

    - by Thomas Tempelmann
    My task is to display the supported document types on an iPhone with OS 3.x, such as .pdf, .rtf, .doc, .ppt, .png, .tiff etc. Now, I have stored these files only encrypted on disk. For security reasons, I want to avoid storing them unencrypted on disk. Hence, I prefer to use loadData:MIMEType:textEncodingName:baseURL: instead of loadRequest: to display the document because loadData allows me to pass the content in a NSData object, i.e. I can decrypt the file in memory and have no need to store it on disk, as it would be required when using loadRequest. The problem is that loadData does not appear to work with all file types: Testing shows that all picture types seem to work fine, as well as PDFs, while the more complex types don't. I get a errors such as: NSURLErrorDomain Code=100 NSURLErrorDomain Code=102 WebView appears to need a truly working URL for accessing the documents as a file, despite me offering all content via the NSData object already. Here's the code I use to display the content: [webView loadData:data MIMEType:type textEncodingName:@"utf-8" baseURL:nil]; The mime-type is properly set, e.g. to "application/msword" for .doc files. Does anyone know how I could get loadData to work with all types that loadRequest supports? Or, alternatively, is there some way I can tell which types do work for sure (i.e. officially sanctioned by Apple) with loadData? Then I can work twofold, creating a temp unencrypted file only for those cases that loadData won't like. Update Looks like I'm not the first one running into this. See here: http://osdir.com/ml/iPhoneSDKDevelopment/2010-03/msg00216.html So, I guess, that's the status quo, and nothing I can do about it. Someone suggested a work-around which might work, though: http://osdir.com/ml/iPhoneSDKDevelopment/2010-03/msg00219.html Basically, the idea is to provide a tiny http server that serves the file (from memory in my case), and then use loadRequest. This is probably a bit more memory-intensive, though, as both the server and the webview will probably both hold the entire contents in memory as two copies then, as opposed to using loadData, where both would rather share the same data object. (Mind you, I'll have to hold the decrypted data in memory, that's the whole point here).

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  • Doubt about adopting CI (Hudson) into an existing automated Build Process (phing, svn)

    - by maraspin
    OUR CURRENT BUILD PROCESS We're a small team of developers (2 to 4 people depending on project) who currently use Phing to deploy code to a staging environment, before going live. We keep our code in a SVN repo, where the trunk holds current active development and, at certain times, we do make branches that we test and then (if successful), tag and export to the staging env. If everything goes well there too, we finally deploy'em in production servers. Actions are highly automated, but always triggered by human intervention. THE DOUBT We'd now like to introduce Continuous Integration (with Hudson) in the process; unfortunately we have a few doubts about activity syncing, since we're afraid that CI could somewhat interfere with our build process and cause certain problems. Considering that an automated CI cycle has a certain frequency of automatically executed actions, we in fact only see 2 possible cases for "integration", each with its own problems: Case A: each CI cycle produces a new branch with its own name; we do use such a name to manually (through phing as it happens now) export the code from the SVN to the staging env. The problem I see here is that (unless specific countermeasures are taken) the number of branches we have can grow out of control (let's suppose we commit often, so that we have a fresh new build/branch every N minutes). Case B: each CI cycle creates a new branch named 'current', for instance, which is tagged with a unique name only when we manually decide to export it to staging; the current branch, at any case is then deleted, as soon as the next CI cycle starts up. The problem we see here is that a new cycle could kick in while someone is tagging/exporting the 'current' branch to staging thus creating an inconsistent build (but maybe here I'm just too pessimist, since I confess I don't know whether SVN offers some built-in protection against this). With all this being said, I was wondering if anyone with similar experiences could be so kind to give us some hints on the subject, since none of the approaches depicted above looks completely satisfing to us. Is there something important we just completely left off in the overall picture? Thanks for your attention &, in advance, for your help!

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  • When should I use Perl's AUTOLOAD?

    - by Robert S. Barnes
    In "Perl Best Practices" the very first line in the section on AUTOLOAD is: Don't use AUTOLOAD However all the cases he describes are dealing with OO or Modules. I have a stand alone script in which some command line switches control which versions of particular functions get defined. Now I know I could just take the conditionals and the evals and stick them naked at the top of my file before everything else, but I find it convenient and cleaner to put them in AUTOLOAD at the end of the file. Is this bad practice / style? If you think so why, and is there a another way to do it? As per brian's request I'm basically using this to do conditional compilation based on command line switches. I don't mind some constructive criticism. sub AUTOLOAD { our $AUTOLOAD; (my $method = $AUTOLOAD) =~ s/.*:://s; # remove package name if ($method eq 'tcpdump' && $tcpdump) { eval q( sub tcpdump { my $msg = shift; warn gf_time()." Thread ".threads->tid().": $msg\n"; } ); } elsif ($method eq 'loginfo' && $debug) { eval q( sub loginfo { my $msg = shift; $msg =~ s/$CRLF/\n/g; print gf_time()." Thread ".threads->tid().": $msg\n"; } ); } elsif ($method eq 'build_get') { if ($pipelining) { eval q( sub build_get { my $url = shift; my $base = shift; $url = "http://".$url unless $url =~ /^http/; return "GET $url HTTP/1.1${CRLF}Host: $base$CRLF$CRLF"; } ); } else { eval q( sub build_get { my $url = shift; my $base = shift; $url = "http://".$url unless $url =~ /^http/; return "GET $url HTTP/1.1${CRLF}Host: $base${CRLF}Connection: close$CRLF$CRLF"; } ); } } elsif ($method eq 'grow') { eval q{ require Convert::Scalar qw(grow); }; if ($@) { eval q( sub grow {} ); } goto &$method; } else { eval "sub $method {}"; return; } die $@ if $@; goto &$method; }

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  • Bluetooth connect to a RS232 adapter in android

    - by ThePosey
    Hello All, I am trying to use the Bluetooth Chat sample API app that google provides to connect to a bluetooth RS232 adapter hooked up to another device. Here is the app for reference: http://developer.android.com/resources/samples/BluetoothChat/index.html And here is the spec sheet for the RS232 connector just for reference: http://serialio.com/download/Docs/BlueSnap-guide-4.77%5FCommands.pdf Well the problem is that when I go to connect to the device with: mmSocket.connect(); (BluetoothSocket::connect()) I always get an IOException error thrown by the connect method. When I do a toString on the exception I get "Service discovery failed". My question is mostly what are the cases that would cause an IOException to get thrown in the connect method? I know those are in the source somewhere but I don't know exactly how the java layer that you write apps in and the C/C++ layer that contains the actual stacks interface. I know that it uses the bluez bluetooth stack which is written in C/C++ but not sure how that ties into the java layer which is what I would think is throwing the exception. Any help on pointing me to where I can try to dissect this issue would be incredible. Also just to note I am able to pair with the RS232 adapter just fine but I am never able to actually connect. Here is the logcat output for more reference: I/ActivityManager( 1018): Displayed activity com.example.android.BluetoothChat/.DeviceListActivity: 326 ms (total 326 ms) E/BluetoothService.cpp( 1018): stopDiscoveryNative: D-Bus error in StopDiscovery: org.bluez.Error.Failed (Invalid discovery session) D/BluetoothChat( 1729): onActivityResult -1 D/BluetoothChatService( 1729): connect to: 00:06:66:03:0C:51 D/BluetoothChatService( 1729): setState() STATE_LISTEN - STATE_CONNECTING E/BluetoothChat( 1729): + ON RESUME + I/BluetoothChat( 1729): MESSAGE_STATE_CHANGE: STATE_CONNECTING I/BluetoothChatService( 1729): BEGIN mConnectThread E/BluetoothService.cpp( 1018): stopDiscoveryNative: D-Bus error in StopDiscovery: org.bluez.Error.Failed (Invalid discovery session) E/BluetoothEventLoop.cpp( 1018): event_filter: Received signal org.bluez.Device:PropertyChanged from /org/bluez/1498/hci0/dev_00_06_66_03_0C_51 I/BluetoothChatService( 1729): CONNECTION FAIL TOSTRING: java.io.IOException: Service discovery failed D/BluetoothChatService( 1729): setState() STATE_CONNECTING - STATE_LISTEN D/BluetoothChatService( 1729): start D/BluetoothChatService( 1729): setState() STATE_LISTEN - STATE_LISTEN I/BluetoothChat( 1729): MESSAGE_STATE_CHANGE: STATE_LISTEN V/BluetoothEventRedirector( 1080): Received android.bleutooth.device.action.UUID I/NotificationService( 1018): enqueueToast pkg=com.example.android.BluetoothChat callback=android.app.ITransientNotification$Stub$Proxy@446327c8 duration=0 I/BluetoothChat( 1729): MESSAGE_STATE_CHANGE: STATE_LISTEN E/BluetoothEventLoop.cpp( 1018): event_filter: Received signal org.bluez.Device:PropertyChanged from /org/bluez/1498/hci0/dev_00_06_66_03_0C_51 V/BluetoothEventRedirector( 1080): Received android.bleutooth.device.action.UUID The device I'm trying to connect to is the 00:06:66:03:0C:51 which I can scan for and apparently pair with just fine.

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  • NSInvalidArgumentException: Illegal attempt to establish a relationship between objects in different

    - by iPhoneDollaraire
    I have an app based on the CoreDataBooks example that uses an addingManagedObjectContext to add an Ingredient to a Cocktail in order to undo the entire add. The CocktailsDetailViewController in turn calls a BrandPickerViewController to (optionally) set a brand name for a given ingredient. Cocktail, Ingredient and Brand are all NSManagedObjects. Cocktail requires at least one Ingredient (baseLiquor) to be set, so I create it when the Cocktail is created. If I add the Cocktail in CocktailsAddViewController : CocktailsDetailViewController (merging into the Cocktail managed object context on save) without setting baseLiquor.brand, then it works to set the Brand from a picker (also stored in the Cocktails managed context) later from the CocktailsDetailViewController. However, if I try to set baseLiquor.brand in CocktailsAddViewController, I get: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Illegal attempt to establish a relationship 'brand' between objects in different contexts' From this question I understand that the issue is that Brand is stored in the app's managedObjectContext and the newly added Ingredient and Cocktail are stored in addingManagedObjectContext, and that passing the ObjectID instead would avoid the crash. What I don't get is how to implement the picker generically so that all of the Ingredients (baseLiquor, mixer, garnish, etc.) can be set during the add, as well as one-by-one from the CocktailsDetailViewController after the Cocktail has been created. In other words, following the CoreDataBooks example, where and when would the ObjectID be turned into the NSManagedObject from the parent MOC in both add and edit cases? -IPD UPDATE - Here's the code: - (IBAction)addCocktail:(id)sender { CocktailsAddViewController *addViewController = [[CocktailsAddViewController alloc] init]; addViewController.title = @"Add Cocktail"; addViewController.delegate = self; // Create a new managed object context for the new book -- set its persistent store coordinator to the same as that from the fetched results controller's context. NSManagedObjectContext *addingContext = [[NSManagedObjectContext alloc] init]; self.addingManagedObjectContext = addingContext; [addingContext release]; [addingManagedObjectContext setPersistentStoreCoordinator:[[fetchedResultsController managedObjectContext] persistentStoreCoordinator]]; Cocktail *newCocktail = (Cocktail *)[NSEntityDescription insertNewObjectForEntityForName:@"Cocktail" inManagedObjectContext:self.addingManagedObjectContext]; newCocktail.baseLiquor = (Ingredient *)[NSEntityDescription insertNewObjectForEntityForName:@"Ingredient" inManagedObjectContext:self.addingManagedObjectContext]; newCocktail.mixer = (Ingredient *)[NSEntityDescription insertNewObjectForEntityForName:@"Ingredient" inManagedObjectContext:self.addingManagedObjectContext]; newCocktail.volume = [NSNumber numberWithInt:0]; addViewController.cocktail = newCocktail; UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:addViewController]; [self.navigationController presentModalViewController:navController animated:YES]; [addViewController release]; [navController release]; }

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  • How to GET a read-only vs editable resource in REST style?

    - by Val
    I'm fairly familiar with REST principles, and have read the relevant dissertation, Wikipedia entry, a bunch of blog posts and StackOverflow questions on the subject, but still haven't found a straightforward answer to a common case: I need to request a resource to display. Depending on the resource's state, I need to render either a read-only or an editable representation. In both cases, I need to GET the resource. How do I construct a URL to get the read-only or editable version? If my user follows a link to GET /resource/<id>, that should suffice to indicate to me that s/he needs the read-only representation. But if I need to server up an editable form, what does that URL look like? GET /resource/<id>/edit is obvious, but it contains a verb in the URL. Changing that to GET /resource/<id>/editable solves that problem, but at a seemingly superficial level. Is that all there is to it -- change verbs to adjectives? If instead I use POST to retrieve the editable version, then how do I distinguish between the POST that initially retrieves it, vs the POST that saves it? My (weak) excuse for using POST would be that retrieving an editable version would cause a change of state on the server: locking the resource. But that only holds if my requirements are to implement such a lock, which is not always the case. PUT fails for the same reason, plus PUT is not enabled by default on the Web servers I'm running, so there are practical reasons not to use it (and DELETE). Note that even in the editable state, I haven't made any changes yet; presumably when I submit the resource to the Web server again, I'd POST it. But to get something that I can later POST, the server has to first serve up a particular representation. I guess another approach would be to have separate resources at the collection level: GET /read-only/resource/<id> and GET /editable/resource/<id> or GET /resource/read-only/<id> and GET /resource/editable/<id> ... but that looks pretty ugly to me. Thoughts?

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  • ! Extra }, or forgotten \endgroup. latex

    - by gzou
    hey, I met these latex format problem, anyone can offer some help? the .tex file: \begin{table}{} \renewcommand{\arraystretch}{1.1} \caption{Cambridge Flow feature definition and description} \label{cambridge-feature}} \centering \begin{tabular}{|c|c|} \hline\bfseries Abbreviation &\bfseries Description\\ \hline serv-port & Server port\\ \hline clnt-port & Client port\\ \hline push-pkts-serv & count of all packets with\\ & push bit set in TCP header (server to client)\\ \hline init-win-bytes-clnt & the total number of bytes \\ & sent in initial window (client to server)\\ \hline init-win-bytes-serv & the total number of bytes sent\\ & in initial window (server to client)\\ \hline avg-seg-size-clnt & average segment size: \\ & data bytes devided by number of packets\\ \hline IP-bytes-med-clnt & median of total bytes in IP packet\\ \hline act-data-pkt-serv & count of packet with at least one byte \\ & of TCP data playload (server to client)\\ \hline data-bytes-var-clnt & variance of total \\ & bytes in packets (client to server)\\ \hline min-seg-size-serv & minimum segment size \\ & observed (server to client)\\ \hline RTT-samples-serv & total number of RTT samples\\ & found (server to client),\\ & {\bf see also \cite{Moore05discriminators}}\\ \hline push-pkts-clnt & count of all packets with push bit set \\ & in TCP header (server to client)\\ \hline \end{tabular} \end{table} and the error message: ! Extra }, or forgotten \endgroup. \@endfloatbox ...pagefalse \outer@nobreak \egroup \color@endbox l.892 \end{table} I've deleted a group-closing symbol because it seems to be spurious, as in $x}$'. But perhaps the } is legitimate and you forgot something else, as in\hbox{$x}'. In such cases the way to recover is to insert both the forgotten and the deleted material, e.g., by typing `I$}'. there is no $ in my table, also this { are matching with the }, and also after I comment the citation, the error remains. anyone can offer help? really appreciate all the comments! ! Extra }, or forgotten \endgroup.

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  • spoj: runlength

    - by user285825
    For RLM problem of SPOJ: This is the problem: "Run-length encoding of a number replaces a run of digits (that is, a sequence of consecutive equivalent digits) with the number of digits followed by the digit itself. For example, 44455 would become 3425 (three fours, two fives). Note that run-length encoding does not necessarily shorten the length of the data: 11 becomes 21, and 42 becomes 1412. If a number has more than nine consecutive digits of the same type, the encoding is done greedily: each run grabs as many digits as it can, so 111111111111111 is encoded as 9161. Implement an integer arithmetic calculator that takes operands and gives results in run-length format. You should support addition, subtraction, multiplication, and division. You won't have to divide by zero or deal with negative numbers. Input/Output The input will consist of several test cases, one per line. For each test case, compute the run-length mathematics expression and output the original expression and the result, as shown in the examples. The (decimal) representation of all operands and results will fit in signed 64-bit integers." These are my testcases: input: 11 + 11 988726 - 978625 12 * 41 1124 / 1112 13 * 33 15 / 16 19222317121013161815142715181017 + 10 10 + 19222317121013161815142715181017 19222317121013161815142715181017 / 19222317121013161815142715181017 19222317121013161815142715181017 / 11 11 / 19222317121013161815142715181017 19222317121013161815142715181017 / 12 12 / 19222317121013161815142715181017 19222317121013161815142715181017 / 141621161816101118141217131817191014 141621161816101118141217131817191014 / 19222317121013161815142715181017 19222317121013161815142715181017 / 141621161816101118141217131817191013 141621161816101118141217131817191013 / 19222317121013161815142715181017 19222317121013161815142715181017 * 11 11 * 19222317121013161815142715181017 19222317121013161815142715181017 * 10 10 * 19222317121013161815142715181017 19222317121013161815142715181017 - 10 19222317121013161815142715181017 - 19222317121013161815142715181017 19222317121013161815142715181017 - 141621161816101118141217131817191014 19222317121013161815142715181017 - 141621161816101118141217131817191013 141621161816101118141217131817191013 + 141621161816101118141217131817191013 141621161816101118141217131817191013 + 141621161816101118141217131817191014 141621161816101118141217131817191014 + 141621161816101118141217131817191013 141621161816101118141217131817191014 + 10 10 + 141621161816101118141217131817191013 141621161816101118141217131817191013 + 11 11 + 141621161816101118141217131817191013 141621161816101118141217131817191013 * 12 12 * 141621161816101118141217131817191013 141621161816101118141217131817191014 - 141621161816101118141217131817191014 141621161816101118141217131817191013 - 141621161816101118141217131817191013 141621161816101118141217131817191013 - 10 141621161816101118141217131817191014 - 11 141621161816101118141217131817191014 - 141621161816101118141217131817191013 141621161816101118141217131817191014 / 141621161816101118141217131817191014 141621161816101118141217131817191014 / 141621161816101118141217131817191013 141621161816101118141217131817191013 / 141621161816101118141217131817191014 141621161816101118141217131817191013 / 141621161816101118141217131817191013 141621161816101118141217131817191014 * 11 11 * 141621161816101118141217131817191014 141621161816101118141217131817191014 / 11 11 / 141621161816101118141217131817191014 10 + 10 10 + 11 10 + 15 15 + 10 11 + 10 11 + 10 10 - 10 15 - 10 10 * 10 10 * 15 15 * 10 10 / 111213 output: 11 + 11 = 12 988726 - 978625 = 919111 12 * 41 = 42 1124 / 1112 = 1112 13 * 33 = 39 15 / 16 = 10 19222317121013161815142715181017 + 10 = 19222317121013161815142715181017 10 + 19222317121013161815142715181017 = 19222317121013161815142715181017 19222317121013161815142715181017 / 19222317121013161815142715181017 = 11 19222317121013161815142715181017 / 11 = 19222317121013161815142715181017 11 / 19222317121013161815142715181017 = 10 19222317121013161815142715181017 / 12 = 141621161816101118141217131817191013 12 / 19222317121013161815142715181017 = 10 19222317121013161815142715181017 / 141621161816101118141217131817191014 = 11 141621161816101118141217131817191014 / 19222317121013161815142715181017 = 10 19222317121013161815142715181017 / 141621161816101118141217131817191013 = 12 141621161816101118141217131817191013 / 19222317121013161815142715181017 = 10 19222317121013161815142715181017 * 11 = 19222317121013161815142715181017 11 * 19222317121013161815142715181017 = 19222317121013161815142715181017 19222317121013161815142715181017 * 10 = 10 10 * 19222317121013161815142715181017 = 10 19222317121013161815142715181017 - 10 = 19222317121013161815142715181017 19222317121013161815142715181017 - 19222317121013161815142715181017 = 10 19222317121013161815142715181017 - 141621161816101118141217131817191014 = 141621161816101118141217131817191013 19222317121013161815142715181017 - 141621161816101118141217131817191013 = 141621161816101118141217131817191014 141621161816101118141217131817191013 + 141621161816101118141217131817191013 = 19222317121013161815142715181016 141621161816101118141217131817191013 + 141621161816101118141217131817191014 = 19222317121013161815142715181017 141621161816101118141217131817191014 + 141621161816101118141217131817191013 = 19222317121013161815142715181017 141621161816101118141217131817191014 + 10 = 141621161816101118141217131817191014 10 + 141621161816101118141217131817191013 = 141621161816101118141217131817191013 141621161816101118141217131817191013 + 11 = 141621161816101118141217131817191014 11 + 141621161816101118141217131817191013 = 141621161816101118141217131817191014 141621161816101118141217131817191013 * 12 = 19222317121013161815142715181016 12 * 141621161816101118141217131817191013 = 19222317121013161815142715181016 141621161816101118141217131817191014 - 141621161816101118141217131817191014 = 10 141621161816101118141217131817191013 - 141621161816101118141217131817191013 = 10 141621161816101118141217131817191013 - 10 = 141621161816101118141217131817191013 141621161816101118141217131817191014 - 11 = 141621161816101118141217131817191013 141621161816101118141217131817191014 - 141621161816101118141217131817191013 = 11 141621161816101118141217131817191014 / 141621161816101118141217131817191014 = 11 141621161816101118141217131817191014 / 141621161816101118141217131817191013 = 11 141621161816101118141217131817191013 / 141621161816101118141217131817191014 = 10 141621161816101118141217131817191013 / 141621161816101118141217131817191013 = 11 141621161816101118141217131817191014 * 11 = 141621161816101118141217131817191014 11 * 141621161816101118141217131817191014 = 141621161816101118141217131817191014 141621161816101118141217131817191014 / 11 = 141621161816101118141217131817191014 11 / 141621161816101118141217131817191014 = 10 10 + 10 = 10 10 + 11 = 11 10 + 15 = 15 15 + 10 = 15 11 + 10 = 11 11 + 10 = 11 10 - 10 = 10 15 - 10 = 15 10 * 10 = 10 10 * 15 = 10 15 * 10 = 10 10 / 111213 = 10 I am getting consistently wrong answer. I generated the above testcases trying to make them as representative as possible (boundary conditions, etc). I am not sure how to test it further. Some guidline would be really appreciated.

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  • Efficiency of Java "Double Brace Initialization"?

    - by Jim Ferrans
    In Hidden Features of Java the top answer mentions Double Brace Initialization, with a very enticing syntax: Set<String> flavors = new HashSet<String>() {{ add("vanilla"); add("strawberry"); add("chocolate"); add("butter pecan"); }}; This idiom creates an anonymous inner class with just an instance initializer in it, which "can use any [...] methods in the containing scope". Main question: Is this as inefficient as it sounds? Should its use be limited to one-off initializations? (And of course showing off!) Second question: The new HashSet must be the "this" used in the instance initializer ... can anyone shed light on the mechanism? Third question: Is this idiom too obscure to use in production code? Summary: Very, very nice answers, thanks everyone. On question (3), people felt the syntax should be clear (though I'd recommend an occasional comment, especially if your code will pass on to developers who may not be familiar with it). On question (1), The generated code should run quickly. The extra .class files do cause jar file clutter, and slow program startup slightly (thanks to coobird for measuring that). Thilo pointed out that garbage collection can be affected, and the memory cost for the extra loaded classes may be a factor in some cases. Question (2) turned out to be most interesting to me. If I understand the answers, what's happening in DBI is that the anonymous inner class extends the class of the object being constructed by the new operator, and hence has a "this" value referencing the instance being constructed. Very neat. Overall, DBI strikes me as something of an intellectual curiousity. Coobird and others point out you can achieve the same effect with Arrays.asList, varargs methods, Google Collections, and the proposed Java 7 Collection literals. Newer JVM languages like Scala, JRuby, and Groovy also offer concise notations for list construction, and interoperate well with Java. Given that DBI clutters up the classpath, slows down class loading a bit, and makes the code a tad more obscure, I'd probably shy away from it. However, I plan to spring this on a friend who's just gotten his SCJP and loves good natured jousts about Java semantics! ;-) Thanks everyone!

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  • Fluent NHibernate Self Referencing Many To Many

    - by Jeremy
    I have an entity called Books that can have a list of more books called RelatedBooks. The abbreviated Book entity looks something likes this: public class Book { public virtual long Id { get; private set; } public virtual IList<Book> RelatedBooks { get; set; } } Here is what the mapping looks like for this relationship HasManyToMany(x => x.RelatedBooks) .ParentKeyColumn("BookId") .ChildKeyColumn("RelatedBookId") .Table("RelatedBooks") .Cascade.SaveUpdate(); Here is a sample of the data that is then generated in the RelatedBooks table: BookId RelatedBookId 1 2 1 3 The problem happens when I Try to delete a book. If I delete the book that has an ID of 1, everything works ok and the RelatedBooks table has the two corresponding records removed. However if I try to delete the book with an ID of 3, I get the error "The DELETE statement conflicted with the REFERENCE constraint "FK5B54405174BAB605". The conflict occurred in database "Test", table "dbo.RelatedBooks", column 'RelatedBookId'". Basically what is happening is the Book cannot be deleted because the record in the RelatedBooks table that has a RelatedBookId of 3 is never deleted. How do I get that record to be deleted when I delete a book? EDIT After changing the Cascade from SaveUpdate() to All(), the same problem still exists if I try to delete the Book with an ID of 3. Also with Cascade set to All(), if delete the Book with and ID of 1, then all 3 books (ID's: 1, 2 and 3) are deleted so that won't work either. Looking at the SQL that is executed when the Book.Delete() method is called when I delete the Book with an ID of 3, it looks like the SELECT statement is looking at the wrong column (which I assume means that the SQL DELETE statment would make the same mistake, therefore never removing that record). Here is the SQL for the RelatedBook SELECT relatedboo0_.BookId as BookId3_ , relatedboo0_.RelatedBookId as RelatedB2_3_ , book1_.Id as Id14_0_ FROM RelatedBooks relatedboo0_ left outer join [Book] book1_ on relatedboo0_.RelatedBookId=book1_.Id WHERE relatedboo0_.BookId=3 The WHERE statment should look something like this for thie particular case: WHERE relatedboo0_.RelatedBookId = 3 SOLUTION Here is what I had to do to get it working for all cases Mapping: HasManyToMany(x => x.RelatedBooks) .ParentKeyColumn("BookId") .ChildKeyColumn("RelatedBookId") .Table("RelatedBooks"); Code: var book = currentSession.Get<Book>(bookId); if (book != null) { //Remove all of the Related Books book.RelatedBooks.Clear(); //Get all other books that have this book as a related book var booksWithRelated = currentSession.CreateCriteria<Book>() .CreateAlias("RelatedBooks", "br") .Add(Restrictions.Eq("br.Id", book.Id)) .List<Book>(); //Remove this book as a Related Book for all other Books foreach (var tempBook in booksWithRelated) { tempBook.RelatedBooks.Remove(book); tempBook.Save(); } //Delete the book book.Delete(); }

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  • Does oneway declaration in Android .aidl guarantee that method will be called in a separate thread?

    - by Dan Menes
    I am designing a framework for a client/server application for Android phones. I am fairly new to both Java and Android (but not new to programming in general, or threaded programming in particular). Sometimes my server and client will be in the same process, and sometimes they will be in different processes, depending on the exact use case. The client and server interfaces look something like the following: IServer.aidl: package com.my.application; interface IServer { /** * Register client callback object */ void registerCallback( in IClient callbackObject ); /** * Do something and report back */ void doSomething( in String what ); . . . } IClient.aidl: package com.my.application; oneway interface IClient { /** * Receive an answer */ void reportBack( in String answer ); . . . } Now here is where it gets interesting. I can foresee use cases where the client calls IServer.doSomething(), which in turn calls IClient.reportBack(), and on the basis of what is reported back, IClient.reportBack() needs to issue another call to IClient.doSomething(). The issue here is that IServer.doSomething() will not, in general, be reentrant. That's OK, as long as IClient.reportBack() is always invoked in a new thread. In that case, I can make sure that the implementation of IServer.doSomething() is always synchronized appropriately so that the call from the new thread blocks until the first call returns. If everything works the way I think it does, then by declaring the IClient interface as oneway, I guarantee this to be the case. At least, I can't think of any way that the call from IServer.doSomething() to IClient.reportBack() can return immediately (what oneway is supposed to ensure), yet IClient.reportBack still be able to reinvoke IServer.doSomething recursively in the same thread. Either a new thread in IServer must be started, or else the old IServer thread can be re-used for the inner call to IServer.doSomething(), but only after the outer call to IServer.doSomething() has returned. So my question is, does everything work the way I think it does? The Android documentation hardly mentions oneway interfaces.

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  • AvalonDock + UserControl + DataGrid + ContextMenu command routing issue

    - by repka
    I have this kind of layout: <Window x:Class="DockAndMenuTest.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:ad="clr-namespace:AvalonDock;assembly=AvalonDock" Title="MainWindow" Height="350" Width="525"> <ad:DockingManager> <ad:DocumentPane> <ad:DockableContent Title="Doh!"> <UserControl> <UserControl.CommandBindings> <CommandBinding Command="Zoom" Executed="ExecuteZoom" CanExecute="CanZoom"/> </UserControl.CommandBindings> <DataGrid Name="_evilGrid"> <DataGrid.Resources> <Style TargetType="DataGridRow"> <Setter Property="ContextMenu"> <Setter.Value> <ContextMenu> <MenuItem Command="Zoom"/> </ContextMenu> </Setter.Value> </Setter> </Style> </DataGrid.Resources> </DataGrid> </UserControl> </ad:DockableContent> </ad:DocumentPane> </ad:DockingManager> </Window> Briefly: ContextMenu is set for each DataGridRow of DataGrid inside UserControl, which in its turn is inside DockableContent of AvalonDock. Code-behind is trivial as well: public partial class MainWindow { public MainWindow() { InitializeComponent(); _evilGrid.ItemsSource = new[] { Tuple.Create(1, 2, 3), Tuple.Create(4, 4, 3), Tuple.Create(6, 7, 1), }; } private void ExecuteZoom(object sender, ExecutedRoutedEventArgs e) { MessageBox.Show("zoom !"); } private void CanZoom(object sender, CanExecuteRoutedEventArgs e) { e.CanExecute = true; } } So here's the problem: right-clicking on the selected row (if it it was selected before the right click) my command comes out disabled. The command is "Zoom" in this case, but can be any other, including a custom one. If I get rid of either docking or UserControl around my grid there are no problems. ListBox doesn't have this issue either. So I don't know what's at fault here. SNOOP shows that in cases when this propagation fails, instead of UserControl, CanExecute is handled by PART_ShowContextMenuButton (Button), which is part of docking header. I've had other issues with UI command propagation within UserControls hosted inside AvalonDock, but this one is the easiest to reproduce.

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  • Wiki-fying a text using LPeg

    - by Stigma
    Long story coming up, but I'll try to keep it brief. I have many pure-text paragraphs which I extract from a system and re-output in wiki format so that the copying of said data is not such an arduous task. This all goes really well, except that there are no automatic references being generated for the 'topics' we have pages for, which end up needing to be added by reading through all the text and adding it in manually by changing Topic to [[Topic]]. First requirement: each topic is only to be made clickable once, which is the first occurrence. Otherwise, it would become a really spammy linkfest, which would detract from readability. To avoid issues with topics that start with the same words Second requirement: overlapping topic names should be handled in such a way that the most 'precise' topic gets the link, and in later occurrences, the less precise topics do not get linked, since they're likely not correct. Example: topics = { "Project", "Mary", "Mr. Moore", "Project Omega"} input = "Mary and Mr. Moore work together on Project Omega. Mr. Moore hates both Mary and Project Omega, but Mary simply loves the Project." output = function_to_be_written(input) -- "[[Mary]] and [[Mr. Moore]] work together on [[Project Omega]]. Mr. Moore hates both Mary and Project Omega, but Mary simply loves the [[Project]]." Now, I quickly figured out a simple or complicated string.gsub() could not get me what I need to satisfy the second requirement, as it provides no way to say 'Consider this match as if it did not happen - I want you to backtrack further'. I need the engine to do something akin to: input = "abc def ghi" -- Looping over the input would, in this order, match the following strings: -- 1) abc def ghi -- 2) abc def -- 3) abc -- 4) def ghi -- 5) def -- 6) ghi Once a string matches an actual topic and has not been replaced before by its wikified version, it is replaced. If this topic has been replaced by a wikified version before, don't replace, but simply continue the matching at the end of the topic. (So for a topic "abc def", it would test "ghi" next in both cases.) Thus I arrive at LPeg. I have read up on it, played with it, but it is considerably complex, and while I think I need to use lpeg.Cmt and lpeg.Cs somehow, I am unable to mix the two properly to make what I want to do work. I am refraining from posting my practice attempts as they are of miserable quality and probably more likely to confuse anyone than assist in clarifying my problem. (Why do I want to use a PEG instead of writing a triple-nested loop myself? Because I don't want to, and it is a great excuse to learn PEGs.. except that I am in over my head a bit. Unless it is not possible with LPeg, the first is not an option.)

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