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  • ActiveRecord Create (not !) Throwing Exception on Validation

    - by myferalprofessor
    So I'm using ActiveRecord model validations to validate a form in a RESTful application. I have a create action that does: @association = Association.new and the receiving end of the form creates a data hash of attributes from the form parameters to save to the database using: @association = user.associations.create(data) I want to simply render the create action if validation fails. The problem is that the .create (not !) method is throwing an exception in cases where the model validation fails. Example: validates_format_of :url, :with => /(^$)|(^(http|https):\/\/[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,5}(([0-9]{1,5})?\/.*)?$)/ix, :message => "Your url doesn't seem valid." in the model produces: ActiveRecord::RecordInvalid Exception: Validation failed: Url Your url doesn't seem valid. I thought .create! is supposed throw an exception whereas .create is not. Am I missing something here? Ruby 1.8.7 patchlevel 173 & rails 2.3.3

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  • How do I serialise a graph in Java without getting StackOverflowException?

    - by Tim Cooper
    I have a graph structure in java, ("graph" as in "edges and nodes") and I'm attempting to serialise it. However, I get "StackOverflowException", despite significantly increasing the JVM stack size. I did some googling, and apparently this is a well known limitation of java serialisation: that it doesn't work for deeply nested object graphs such as long linked lists - it uses a stack record for each link in the chain, and it doesn't do anything clever such as a breadth-first traversal, and therefore you very quickly get a stack overflow. The recommended solution is to customise the serialisation code by overriding readObject() and writeObject(), however this seems a little complex to me. (It may or may not be relevant, but I'm storing a bunch of fields on each edge in the graph so I have a class JuNode which contains a member ArrayList<JuEdge> links;, i.e. there are 2 classes involved, rather than plain object references from one node to another. It shouldn't matter for the purposes of the question). My question is threefold: (a) why don't the implementors of Java rectify this limitation or are they already working on it? (I can't believe I'm the first person to ever want to serialise a graph in java) (b) is there a better way? Is there some drop-in alternative to the default serialisation classes that does it in a cleverer way? (c) if my best option is to get my hands dirty with low-level code, does someone have an example of graph serialisation java source-code that can use to learn how to do it?

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  • Problem with literal arguments in the PATTERN string for a python 2to3 fixer

    - by Zxaos
    Hi folks. I'm writing a fixer for the 2to3 tool in python. In my pattern string, I have a section where I'd like to match an empty string as an argument, or an empty unicode string. The relevant chunk of my pattern looks like: (args='""' | args='u""') My issue is the second option never matches. Even if it's alone, it won't match. However, if I simply say args=any and then output args, I can catch cases where args is exactly equal to the second option. Is there some weird unicode handling thing going on? Why won't the second literal option ever match?

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  • LBA48 in Linux SCSI ATA Passthrough

    - by Ben Englert
    I am writing a custom disk monitoring/diagnostics app which, among other things, needs to do stuff to SATA disks behind a SAS PCI card under Linux. So far I am following this guide as well as the example code in sg_utils to pass ATA taskfiles through the SCSI layer. Seems to be working okay. However, in both cases, the CDB data structure (pointed to by the cmdp member of the sg_io argument to the ioctl) has only one unsigned char worth of space for the number of sectors. If you look at the ata_taskfile structure in linux\ata.h you'll see that it has an "nsect" and a "hob_nsect" field - high order bits for the sector count, to support LBA48. It turns out that in my application I need LBA48 support. So, anyone know how to set up an sg_io_hdr structure with an LBA48 sector count?

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  • Making a relevant search of text in database using regex

    - by madphp
    Can anyone tell me how I could count the possible instances of a keyword in a block of text? I've split a search term up into separate tokens, so just need to run through and do a count for every instance and removing punctuation or other special characters when making the count. Secondly, if someone has inserted search terms surrounded by double quotes, i want to be able to skip explode, but just count instances of that exact phrase. It doesn't have to be case sensitive and I would like to remove punctuation from the phrase when doing the count. Thirdly, in both cases i want to be able to ignore wordpress and html tags. Lastly, if anyone know any good tutorials for relevant searches that answer the questions above, that would cool too. I've got this far. $results = $wpdb->get_results($sql); $tokens = explode('search_terms'); // Re-arrange Relevant Results foreach ($results As $forum_topic){ foreach($tokens As $token){ // count tokens in topic_title if ($token ){ } } }

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  • StringBuilder related question

    - by Sef
    I have written a program for a stack. (http://stackoverflow.com/questions/2617367?tab=votes#tab-top) For this i needed a StringBuilder to be able to show me what was in the stack else i would get the class name instead of the actual values inside. My question is there any other way except for a StringBuilder for such kind of problem? Also in what other kind of cases does this kind of problem happen? Also the way i have written the StringBuilder felt very awkward when i needed several things on 1 line. public override string ToString() { StringBuilder builder = new StringBuilder(); foreach (int value in tabel) { builder.Append(value); builder.Append(" "); } if (tabel.Length == tabel.Length) // this is a bit messy, since I couldn't append after the rest above { builder.Append("(top:"); builder.Append(top); builder.Append(")"); } return builder.ToString(); }/*ToString*/

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  • Java: How to test methods that call System.exit()?

    - by Chris Conway
    I've got a few methods that should call System.exit() on certain inputs. Unfortunately, testing these cases causes JUnit to terminate! Putting the method calls in a new Thread doesn't seem to help, since System.exit() terminates the JVM, not just the current thread. Are there any common patterns for dealing with this? For example, can I subsitute a stub for System.exit()? [EDIT] The class in question is actually a command-line tool which I'm attempting to test inside JUnit. Maybe JUnit is simply not the right tool for the job? Suggestions for complementary regression testing tools are welcome (preferably something that integrates well with JUnit and EclEmma).

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  • C++: Best text accumulator

    - by MInner
    Text gets accumulates piecemeal before being sent to client. Now we use own class that allocates memory for each piece as char massive. (Anyway, works like char[][] + std::list<char*>). Then we build the whole string, convert it into std::sting and then create boost::asio::streambuf using it. That's slow enough, I assume. Correct me if I'm wrong. I know, in many cases simple FILE type from stdio.h is used. How does it works? Allocates memory at every write into it. So, is it faster and is there any way to read into boost::asio::streambuf from FILE?

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  • heirarchial data from self referencing table in tree form

    - by Beta033
    Ii looks like this has been asked and answered in all the simple cases, excluding the one that i'm having trouble with. I've tried using a recursive CTE to generate this, however maybe a cursor would be better? or maybe a set of recursive functions will do the trick? Can this be done in a cte? consider the following table PrimaryKey ParentKey 1 NULL 2 1 3 6 4 7 5 2 6 1 7 NULL should yield PK 1 -2 --5 -6 --3 7 -4 where the number of - marks equal the depth, my primary difficulty is the ordering.

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  • C# getpixels() gets the correct value on xp and vista but is slightly off when used on windows 7

    - by user352288
    I have a C# program that works correctly on xp and vista but it needs to be used on windows 7, I have not been able to come up with a solution, it appears that getpixels just doesn't work right on windows 7. I am getting one of the RGB values because I am dealing with tiff grayscale images. System.Drawing.Bitmap image;// this is in a separate class image = new Bitmap(destination);// this is in the constructor Color t = image.GetPixel(j, i); // this is in a separate function int s = t.R when I print s, for example, image(0,0), it is supposed to be 220, it will be 221 I am doing edge detection on an image and I have to go through the image pixel by pixel, I have run the exact same program on XP,Vista,windows7 and windows 7 got different values. It wouldn't let me post images at all and only one link. The first image is the original image, the second is the correct image, also the one I get with XP and Vista, the final image is the image when running the same program in Windows 7. There is not much of a visible difference but it matters for what I am doing. Thanks for the help, it seems that I am having a hard time explaining my problem.

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  • Switch statement for string matching in JavaScript

    - by yaya3
    How do I write a swtich for the following conditional? If the url contains "foo", then settings.base_url is "bar". The following is achieving the effect required but I've a feeling this would be more manageable in a switch: var doc_location = document.location.href; var url_strip = new RegExp("http:\/\/.*\/"); var base_url = url_strip.exec(doc_location) var base_url_string = base_url[0]; //BASE URL CASES // LOCAL if (base_url_string.indexOf('xxx.local') > -1) { settings = { "base_url" : "http://xxx.local/" }; } // DEV if (base_url_string.indexOf('xxx.dev.yyy.com') > -1) { settings = { "base_url" : "http://xxx.dev.yyy.com/xxx/" }; } Thanks

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  • Python - react to custom keyboard interrupt

    - by flixic
    Hello. I am writing python chatbot that displays output through console. Every half second it asks server for updates, and responds to message. In the console I can see chat log. This is sufficient in most cases, however, sometimes I want to interrupt normal workflow and write custom chat answer myself. I would love to be able to press a button (or combination) that would switch to "custom reply mode". What is the best way to do that, or achieve similar result? Thanks a lot!

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  • Reusing of a PreparedStatement between methods?

    - by MRalwasser
    We all know that we should rather reuse a JDBC PreparedStatement than creating a new instance within a loop. But how to deal with PreparedStatement reuse between different method invocations? Does the reuse-"rule" still count? Should I really consider using a field for the PreparedStatement or should I close and re-create the prepared statement in every invocation? (Of course an instance of such a class would be bound to a Connection which might be a disadvantage) I am aware that the ideal answer might be "it depends". But I am looking for a best practice for less experienced developers that they will do the right choice in most of the cases.

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  • Where would async calls make sense in an ASP.net (MVC) Web Application?

    - by Michael Stum
    I'm just wondering, if I have an ASP.net Web Application, either WebForms or MVC, is there any situation where doing stuff asynchronously would make sense? The Web Server already handles threading for me in that it spins up multiple threads to handle requests, and most request processing is rather simple and straight forward. I see some use for when stuff truly is a) expensive and b) can be parallelized. but these are the minority cases (at least from what I've encountered). Is there any gain from async in the simple "Read some input, do some CRUD, display some output" scenario?

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  • When can I find out the width/height of my view

    - by michael
    When is the earliest I can find out the actual (after layout) width/height of my view? I tried to do that @Override protected void onFinishInflate() { super.onFinishInflate(); w = getWidth(); h = getHeight(); } But it gives me 0. I have cases in which the view is invisible in the beginning and that programmically become visible. I think I can do that in onDraw(), but i dont' want to do that in everything I draw() something.

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  • Window bounds set on window using AppleScript in OS X are being ignored

    - by Jesse
    I am trying to create a small AppleScript to create and move some Terminal windows around my screen. The problem I am running into is that in some cases, it seems that OS X is ignoring the bounds I am setting. Using the AppleScript Editor: tell application "Terminal" to set the bounds of the first window to {0, 50, 600, 700} tell application "Terminal" to get the bounds of the first window Shows the following in the Event Log: tell application "Terminal" activate set bounds of window 1 to {0, 50, 600, 700} get bounds of window 1 --> {0, 22, 600, 672} end tell Result: {0, 22, 600, 672} Visually inspecting the window that is created when the script runs shows that Result bounds are the ones being used by the window. Any ideas?

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  • How to have tortoisesvn Always freeze svn:externals for tags

    - by dnndeveloper
    Is this possible with tortoiseSVN?: Always freeze svn:externals for tags the scenario is our trunk will always use the 'head' revision for externals, however when we create 'tags' we would like for them to have a revision set for externals to properly 'freeze' them at a specific point in time. Thanks! Update Thanks to everyone for your feedback/info. Since I could not find anything that would completely meet our needs (tried smartsvn and svncopy.pl) I made a console app that so far has passed all our test cases. A high level overview: The app takes a repository URL then looks for all externals and adds the last commit revision for them - I do a "svn info" and get the "commit revision". The app works with both folder and single file externals. Here is the source code and complete setup files: http://svnxf.codeplex.com/

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  • Where is rebol fill-pen documented (to get glow effect on a round rectangle) ?

    - by Rebol Tutorial
    There is some discussion here about fill-pen http://www.mail-archive.com/[email protected]/msg02019.html But I can't see documentation about cubic, diamond, etc... effect for fill-pen in rebol's official doc ? I'm trying to draw some round rectangle with glowing effect but don't really understand the parameters I'm playing with so I can't get exactly what I'd like (I'd like the glow effect starting from the center not from the dark left top corner): view layout [ box 278x185 effect [ ; default box face size is 100x100 draw [ anti-alias on ; information for the next draw element (not required) line-width 2.5 ; number of pixels in width of the border pen black ; color of the edge of the next draw element ; fill pen is a little complex: ;fill-pen 10x10 0 90 0 1 1 0.0.0 255.0.0 255.0.255 fill-pen radial 20x20 5 55 5 5 10 0.0.0 55.0.5 55.0.5 ; the draw element box ; another box drawn as an effect 15 ; size of rounding in pixels 0x0 ; upper left corner 278x170 ; lower right corner ] ] ]

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  • Where to handle fatal exceptions

    - by Stephen Swensen
    I am considering a design where all fatal exceptions will be handled using a custom UncaughtExceptionHandler in a Swing application. This will include unanticipated RuntimeExceptions but also custom exceptions which are thrown when critical resources are unavailable or otherwise fail (e.g. a settings file not found, or a server communication error). The UncaughtExceptionHandler will do different things depending on the specific custom exception (and one thing for all the unanticipated), but in all cases the application will show the user an error message and exit. The alternative would be to keep the UncaughtExceptionHandler for all unanticipated exceptions, but handle all other fatal scenarios close to their origin. Is the design I'm considering sound, or should I use the alternative?

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  • SQL select all items of an owner from an item-to-owner table

    - by kdobrev
    I have a table bike_to_owner. I would like to select current items owned by a specific user. Table structure is CREATE TABLE IF NOT EXISTS `bike_to_owner` ( `bike_id` int(10) unsigned NOT NULL, `user_id` int(10) unsigned NOT NULL, `last_change_date` date NOT NULL, PRIMARY KEY (`bike_id`,`user_id`,`last_change_date`) ) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci; In the profile page of the user I would like to display all his/her current possessions. I wrote this statement: SELECT `bike_id`,`user_id`,max(last_change_date) FROM `bike_to_owner` WHERE `user_id` = 3 group by `last_change_date` but i'm not quite sure it works correctly in all cases. Can you please verify this is correct and if not suggest me something better. Using php/mysql. Thanks in advance!

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  • How should I declare default values for instance variables in Python?

    - by int3
    Should I give my class members default values like this: class Foo: num = 1 or like this? class Foo: def __init__(self): self.num = 1 In this question I discovered that in both cases, bar = Foo() bar.num += 1 is a well-defined operation. I understand that the first method will give me a class variable while the second one will not. However, if I do not require a class variable, but only need to set a default value for my instance variables, are both methods equally good? Or one of them more 'pythonic' than the other? One thing I've noticed is that in the Django tutorial, they use the second method to declare Models. Personally I think the second method is more elegant, but I'd like to know what the 'standard' way is.

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  • What tricks can be used to type and edit code faster?

    - by Thomas
    As Jeff Atwood noted, we are typists first, programmers second. Fast typing and editing may not be essential to be a good programmer, but it certainly helps. I noticed that I consciously and subconsciously use various tricks to get my intent across to the computer as fast as possible. What tricks can be used to type and edit code faster? I'm hoping to collect a nice list here that we can all learn from, so that we can be ever so slightly more productive. One trick per answer please! (This is not about typing speed in general. There are other questions about that. It's also not about general answers like "learn your editor's shortcut keys". Think of this topic as micro-optimizations for specific cases. See my own answers for examples of what I mean.)

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  • What are real-world examples of Gradle's dependency graph?

    - by Michael Easter
    As noted in the documentation, Gradle uses a directed acyclic graph (DAG) to build a dependency graph. From my understanding, having separate cycles for evaluation and execution is a major feature for a build tool. e.g. The Gradle doc states that this enables some features that would otherwise be impossible. I'm interested in real-world examples that illustrate the power of this feature. What are some use-cases for which a dependency graph is important? I'm especially interested in personal stories from the field, whether with Gradle or a similarly equipped tool. I am making this 'community wiki' from the outset, as it will be difficult to assess a 'correct' answer.

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  • Why use hashing to create pathnames for large collections of files?

    - by Stephen
    Hi, I noticed a number of cases where an application or database stored collections of files/blobs using a has to determine the path and filename. I believe the intended outcome is a situation where the path never gets too deep, or the folders ever get too full - too many files (or folders) in a folder making for slower access. EDIT: Examples are often Digital libraries or repositories, though the simplest example I can think of (that can be installed in about 30s) is the Zotero document/citation database. Why do this? EDIT: thanks Mat for the answer - does this technique of using a hash to create a file path have a name? Is it a pattern? I'd like to read more, but have failed to find anything in the ACM Digital Library

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  • Send through Email, or store in database?

    - by user156814
    I have wondered when it is best to send an email, and when its best to store data in a database/log file. Everytime a user wants to contact me or inform me of soething, I suppose an email is best.. but is an email always preferred over other ways, and in what cases. Possible reasons for being contacted I can think of are questions, suggestions, feedback, reporting abuse, advertising, etc... I assume email, "why add unnecessary things to the DB?", but I figure data in DB would be a lot easier to manage. Whats the better/best way to be informed of things like this.. What is the best way for you (webmaster) to be informed of something by users? through email, or some other way

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