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  • How to keep Java Frame from waiting?

    - by pypmannetjies
    I am writing a genetic algorithm that approximates an image with a polygon. While going through the different generations, I'd like to output the progress to a JFrame. However, it seems like the JFrame waits until the GA's while loop finishes to display something. I don't believe it's a problem like repainting, since it eventually does display everything once the while loop exits. I want to GUI to update dynamically even when the while loop is running. Here is my code: while (some conditions) { //do some other stuff gui.displayPolygon(best); gui.displayFitness(fitness); gui.setVisible(true); } public void displayPolygon(Polygon poly) { BufferedImage bpoly = ImageProcessor.createImageFromPoly(poly); ImageProcessor.displayImage(bpoly, polyPanel); this.setVisible(true); } public static void displayImage(BufferedImage bimg, JPanel panel) { panel.removeAll(); panel.setBounds(0, 0, bimg.getWidth(), bimg.getHeight()); JImagePanel innerPanel = new JImagePanel(bimg, 25, 25); panel.add(innerPanel); innerPanel.setLocation(25, 25); innerPanel.setVisible(true); panel.setVisible(true); }

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  • How to extract byte-array from one xml and store it in another in Java

    - by grobartn
    So I am using DocumentBuilderFactory and DocumentBuilder to parse an xml. So it is DOM parser. But what I am trying to do is extract byte-array data (its an image encoded in base64) Store it in one object and later in code write it out to another xml encoded in base64. What is the best way to store this in btw. Store it as string? or as ByteArray? How can I extract byte array data in best way and write it out. I am not experienced with this so wanted to get opinion from the group. UPDATE: I am given XML I do not have control of incoming XML that comes in binary64 encoded < byte-array > ... base64 encoded image ... < /byte-array > Using parser I have I need to store this node and question is should that be byte or string and then writing it out to another node in new xml. again in base64 encoding. thanks

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  • Nested Resource testing RSpec

    - by Joseph DelCioppio
    I have two models: class Solution < ActiveRecord::Base belongs_to :owner, :class_name => "User", :foreign_key => :user_id end class User < ActiveRecord::Base has_many :solutions end with the following routing: map.resources :users, :has_many => :solutions and here is the SolutionsController: class SolutionsController < ApplicationController before_filter :load_user def index @solutions = @user.solutions end private def load_user @user = User.find(params[:user_id]) unless params[:user_id].nil? end end Can anybody help me with writing a test for the index action? So far I have tried the following but it doesn't work: describe SolutionsController do before(:each) do @user = Factory.create(:user) @solutions = 7.times{Factory.build(:solution, :owner => @user)} @user.stub!(:solutions).and_return(@solutions) end it "should find all of the solutions owned by a user" do @user.should_receive(:solutions) get :index, :user_id => @user.id end end And I get the following error: Spec::Mocks::MockExpectationError in 'SolutionsController GET index, when the user owns the software he is viewing should find all of the solutions owned by a user' #<User:0x000000041c53e0> expected :solutions with (any args) once, but received it 0 times Thanks in advance for all the help. Joe

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  • Char C question about encoding signed/unsigned.

    - by drigoSkalWalker
    Hi guys. I read that C not define if a char is signed or unsigned, and in GCC page this says that it can be signed on x86 and unsigned in PowerPPC and ARM. Okey, I'm writing a program with GLIB that define char as gchar (not more than it, only a way for standardization). My question is, what about UTF-8? It use more than an block of memory? Say that I have a variable unsigned char *string = "My string with UTF8 enconding ~ çã"; See, if I declare my variable as unsigned I will have only 127 values (so my program will to store more blocks of mem) or the UTF-8 change to negative too? Sorry if I can't explain it correctly, but I think that i is a bit complex. NOTE: Thanks for all answer I don't understand how it is interpreted normally. I think that like ascii, if I have a signed and unsigned char on my program, the strings have diferently values, and it leads to confuse, imagine it in utf8 so.

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  • How can I write an XML on my hard drive to GetRequestStream

    - by swolff1978
    I need to post raw xml to a site and read the response. With the following code I keep getting an "Unknown File Format" error and I'm not sure why. XmlDocument sampleRequest = new XmlDocument(); sampleRequest.Load(@"C:\SampleRequest.xml"); byte[] bytes = Encoding.UTF8.GetBytes(sampleRequest.ToString()); string uri = "https://www.sample-gateway.com/gw.aspx"; req = WebRequest.Create(uri); req.Method = "POST"; req.ContentLength = bytes.Length; req.ContentType = "text/xml"; using (var requestStream = req.GetRequestStream()) { requestStream.Write(bytes, 0, bytes.Length); } // Send the data to the webserver rsp = req.GetResponse(); XmlDocument responseXML = new XmlDocument(); using (var responseStream = rsp.GetResponseStream()) { responseXML.Load(responseStream); } I am fairly certain my issue is what/how I am writing to the requestStream so.. How can I modify that code so that I may write an xml located on the hard drive to the request stream?

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  • parsing the output of the 'w' command?

    - by Blackbinary
    I'm writing a program which requires knowledge of the current load on the system, and the activity of any users (it's a load balancer). This is a university assignment, and I am required to use the w command. I'm having a hard time parsing this command because it is very verbose. Any suggestions on what I can do would be appreciated. This is a small part of the program, and I am free to use whatever method i like. The most condensed version of w which still has the information I require is `w -u -s -f' which produces this: 10:13:43 up 9:57, 2 users, load average: 0.00, 0.00, 0.00 USER TTY IDLE WHAT fsm tty7 22:44m x-session-manager fsm pts/0 0.00s w -u -s -f So out of that, I am interested in the first number after load average and the smallest idle time (so i will need to parse them all). My background process will call w, so the fact that w is the lowest idle time will not matter (all i will see is the tty time). Do you have any ideas? Thanks (I am allowed to use alternative unix commands, like grep, if that helps).

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  • Fastest way to become a MySQL expert?

    - by Kerry
    I have been using MySQL for years, mainly on smaller projects until the last year or so. I'm not sure if it's the nature of the language or my lack of real tutorials that gives me the feeling of being unsure if what I'm writing is the proper way for optimization purposes and scaling purposes. While self-taught in PHP I'm very sure of myself and the code I write, easily can compare it to others and so on. With MySQL, I'm not sure whether (and in what cases) an INNER JOIN or LEFT JOIN should be used, nor am I aware of the large amount of functionality that it has. While I've written code for databases that handled tens of millions of records, I don't know if it's optimum. I often find that a small tweak will make a query take less than 1/10 of the original time... but how do I know that my current query isn't also slow? I would like to become completely confident in this field in the ability to optimize databases and be scalable. Use is not a problem -- I use it on a daily basis in a number of different ways. So, the question is, what's the path? Reading a book? Website/tutorials? Recommendations?

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  • Avoid an "out of memory error" in Java(eclipse), when using large data structure?

    - by gnomed
    OK, so I am writing a program that unfortunately needs to use a huge data structure to complete its work, but it is failing with a "out of memory error" during its initialization. While I understand entirely what that means and why it is a problem, I am having trouble overcoming it, since my program needs to use this large structure and I don't know any other way to store it. The program first indexes a large corpus of text files that I provide. This works fine. Then it uses this index to initialize a large 2D array. This array will have nXn entries, where "n" is the number of unique words in the corpus of text. For the relatively small chunk I am testing it on(about 60 files) it needs to make approximately 30,000x30,000 entries. this will probably be bigger once I run it on my full intended corpus too. It consistently fails every time, after it indexes, while it is initializing the data structure(to be worked on later). Things I have done include: revamp my code to use a primitive "int[]" instead of a "TreeMap" eliminate redundant structures, etc... Also, I have run eclipse with "eclipse -vmargs -Xmx2g" to max out my allocated memory I am fairly confident this is not going to be a simple line of code solution, but is most likely going to require a very new approach. I am looking for what that approach is, any ideas? Thanks, B.

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  • Splitting 25mb .txt file into smaller files using text delimiter

    - by user574141
    Regards, SO I am new to python and Perl. I have been trying to solve a simple problem and getting tied in knots with syntax. I hope someone has the time and patience to help. I have a 25mb file in ".txt" format which contains news-wire articles going back to 1970. Each news story is concatenated to the next, with only the "Copyright" statement to delimit. Each news story starts with "Item XX of XXX DOCUMENTS". There are certain metadata that are repeated throughout, I will use these for tagging later on. I wish to split this 25mb file into separate .txt files, each containing one news story (i.e. the text between "DOCUMENTS" and "Copyright", saving each with a different name (obviously). I am trying to 1 ) open the file... 2) iterate over lines in the file checking for the eof delimiter, and if it is not present writing the line to a list 3)write that list to a seperate small file. I'm having big problems with changing filenames using the counter, and how do I make Python start from where I left off, is the "seek" function appropriate? so far I have been trying this approach, completely unsuccessfully: myfile = open ("myfile.txt", 'r') filenumber = 0 for line in myfile.readline(): filenumber += 1 w=0 while myfile.readline() != '\s+DOCUMENTS\s*\n' ### read my line into a list mysmallfile()['w'] = [myfile.readline()] w += 1 output = open('C:\\Users\\dunner7\\Documents\###how do I change the filename each iteration???', 'w') output.writelines(mysmallfile) ###go back to start. Thank you for your time and patience. RD

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  • Modelling in Agile Development

    - by bertzzie
    I'm writing a bachelor dissertation report where I'm developing a system with Agile methodology. Given that the development is an one man show, of course the "Agile" I did was not really agile at all (from my understanding at least). So I want some perspective from SO crowds, who is of course a professional, real world, developer with tons of experience. I think real world experience is better than the theory and experiments that I did. My question is: Do we model during development time when using Agile? UML? DFD? Or a Functional Specification is enough1? If modelling is not really necessary, what do we use to communicate to the user, as the user almost always won't understand UML or DFD? For my system, I use UI & UX Design with heavy prototyping, but then I don't have time to draw UML any more. Which one is better? 1 http://www.joelonsoftware.com/articles/fog0000000036.html I hope the question's not "subjective and argumentative" as I know this question exist because of my lack of understanding in the agile development. If it is, could someone just give me a pointer or reference about that? Possible duplicate: Do you use UML in Agile development practices?

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  • Changing <object> height and width works in Chrome but not Firefox or IE. Why?

    - by Michael Hopkins
    I am making a site with two Youtube videos. These videos use the raw embed code from Youtube. The site's design doesn't work with any of the default Youtube sizes, so I am writing code to automatically resize the video. Here is my code. There will never be more than these two tags on the page, otherwise I'd do a better job selecting the videos. <script language='JavaScript' type='text/javascript'> var x=document.getElementsByTagName('object'); x.[0].width='350'; x.[0].height='350'; x.[1].width='350'; x.[1].height='350'; </script> For reference, here's a sample default Youtube embed that the code might alter: <object width="480" height="385"> <param name="movie" value="http://www.youtube-nocookie.com/v/zSgiXGELjbc&hl=en_US&fs=1&rel=0"></param> <param name="allowFullScreen" value="true"></param> <param name="allowscriptaccess" value="always"></param> <embed src="http://www.youtube-nocookie.com/v/zSgiXGELjbc&hl=en_US&fs=1&rel=0" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed> </object> In Chrome, the video players sit perfectly in a 350x350 box. In IE and FF (latest versions), the videos are the unchanged, normal size. I cannot find anything in Google that explans why this won't work. I have tried using setattribute, for loops, adjusting both and , single-quotes and double-quotes, etc. Any ideas what is going wrong?

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  • Handling Corrupted JPEGs in C#

    - by ddango
    We have a process that pulls images from a remote server. Most of the time, we're good to go, the images are valid, we don't timeout, etc. However, every once and awhile we see this error similar to this: Unhandled Exception: System.Runtime.InteropServices.ExternalException: A generic error occurred in GDI+. at System.Drawing.Image.Save(Stream stream, ImageCodecInfo encoder, EncoderPa rameters encoderParams) at ConsoleApplication1.Program.Main(String[] args) in C:\images\ConsoleApplic ation1\ConsoleApplication1\Program.cs:line 24 After not being able to reproduce it locally, we looked closer at the image, and realized that there were artifacts, making us suspect corruption. Created an ugly little unit test with only the image in question, and was unable to reproduce the error on Windows 7 as was expected. But after running our unit test on Windows Server 2008, we see this error every time. Is there a way to specify non-strictness for jpegs when writing them? Some sort of check/fix we can use? Unit test snippet: var r = ReadFile("C:\\images\\ConsoleApplication1\\test.jpg"); using (var imgStream = new MemoryStream(r)) { using (var ms = new MemoryStream()) { var guid = Guid.NewGuid(); var fileName = "C:\\images\\ConsoleApplication1\\t" + guid + ".jpg"; Image.FromStream(imgStream).Save(ms, ImageFormat.Jpeg); using (FileStream fs = File.Create(fileName)) { fs.Write(ms.GetBuffer(), 0, ms.GetBuffer().Length); } } }

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  • Forwarding keypresses in GTK

    - by dguaraglia
    I'm writing a bit of code for a Gedit plugin. I'm using Python and the interface (obviously) is GTK. So, the issue I'm having is quite simple: I have a search box (a gtk.Entry) and right below I have a results box (a gtk.TreeView). Right after you type something in the search box you are presented a bunch of results, and I would like the user to be able to press the Up/Down keys to select one, Enter to choose it, and be done. Thing is, I can't seem to find a way to forward the Up/Down keypress to the TreeView. Currently I have this piece of code: def __onSearchKeyPress(self, widget, event): """ Forward up and down keys to the tree. """ if event.keyval in [gtk.keysyms.Up, gtk.keysyms.Down]: print "pressed up or down" e = gtk.gdk.Event(gtk.gdk.KEY_PRESS) e.keyval = event.keyval e.window = self.browser.window e.send_event = True self.browser.emit("key-press-event", e) return True I can clearly see I'm receiving the right kind of event, but the event I'm sending gets ignored by the TreeView. Any ideas? Thanks in advance people.

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  • execute a string of PHP code on the command line

    - by Matthew J Morrison
    I'd like to be able to run a line of PHP code on the command line similar to how the following options work: :~> perl -e "print 'hi';" :~> python -c "print 'hi'" :~> ruby -e "puts 'hi'" I'd like to be able to do: :~> php "echo 'hi';" I've read that there is a -r option that can do what I need for php, however it doesn't appear to be available when I try to use it. I've tried using PHP 5.2.13 and PHP 4.4.9 and neither have an -r option available. I wrote this script (that I called run_php.php) - which works, but I'm not a huge fan of it just because I feel like there should be a more "correct" way to do it. #!/usr/bin/php5 -q <?php echo eval($argv[1]); ?> My question is: is there a -r option? If so, why is it not available when I run --help? If there is no -r option, what is the best way to do this (without writing an intermediary script if possible)? Thanks!

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  • Is it possible in Perl to require a subroutine call is made?

    - by MitchelWB
    I don't know enough about Perl to even know what I'm asking for exactly, but I'm writing a series of subroutines to be available for many individual scripts that all process different incoming flat files. The process is far from perfect, but it's what I've got to deal with and I'm trying to build myself a small library of subs that make it easier for me to manage it all. Each script handles a different incoming flat file with it's own formatting, sorting, grouping and outputting requirements. One common aspect is that we have small text files that house counters that are used to name the output files so that we have no duplicate file names. Because the processing of the data is different for each file, I need to open the file to get my counter value, because this is a common operation, I'd like to put it in a sub to retrieve the counter. But then need to write specific code to process the data. And would like a second sub that allows me to update the counter with the counter once I've processed the data. Is there a way to make the second sub call a requirement if the first one is called? Ideally if it could even be an error that would prevent the script from running at all much like a syntax error. EDIT: Here is a little [ugly and simplified] psuedo-code to give a better feel for what the current process is: require "importLibrary.plx"; #open data source file open DataIn, $filename; #call getCounterInfo from importLibrary.plx to get the counter value from counter file $counter = &getCounterInfo($counterFileName); while (<DataIn>) { #Process data based on unique formatting and requirements #output to task files based on requirements and name files using the $counter #increment $counter } #update counter file with new value of $counter &updateCounterInfo($counter);

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  • delete vs execSQL commands android

    - by erik
    so i have a databas, SQLiteDatabase db I am writing a couple private methods in my manager class that will be called by a public method: public void updateData (MakeabilityModel newData){ SQLiteDatabase db = this.getWritableDatabase(); db.beginTransaction(); try { reWriteSVTable(db, list); db.setTransactionSuccessful(); } catch (Exception e){ //TODO through rollback message? e.printStackTrace(); } finally { db.endTransaction(); } } //Private Methods private void clearTable(SQLiteDatabase db, String table){ db.delete(table, null, null); } private void reWriteSVTable(SQLiteDatabase db, List<MakeabilityLens> lenses){ clearTable(db, singleVision); ContentValues cv; for(int i=0; i<lenses.size(); i++){ cv = new ContentValues(); cv.put(colScreenID, hsID); cv.put(colIconID, id); cv.put(colRank, hsTotal); db.insert(isLookUp, colID, cv); } } My question is this.. i want to be able to throw sql exceptions back to the public method so that if there is an exception, it will kill the transaction and rollback ALL data.. it appears that using delete() and insert() methods are cleaner than execSQL() but don't throw sqlExceptions. execSQL() on the other hand does? do i need to uses execSQL and how do i insure that hsould it throws an exception in any of the private methods that it will catch it and roll it back in the private method

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  • ReWriteRule is redirecting rather rewriting

    - by James Doc
    At the moment I have two machines that I do web development on; an iMac for work at the office and a MacBook for when I have to work on the move. They both running OS X 10.6 have the same version of PHP, Apache, etc running on them. Both computers have the same files of the website, including the .htaccess file (see below). On the MacBook the URLs are rewritten nicely, masking the URL they are pointing to (eg site/page/page-name), however on the iMac they simply redirect to the page (eg site/index.php?method=page&value=page-name) which is making switching back and forth between machines a bit of a pain! I'm sure it must be a config setting somewhere, but I can't for the life of me find it. Has anyone got a remedy? Many thanks. I'm fairly convinced there is a much nice way of writing this htaccess file without loosing access several key folders as well! Options +FollowSymlinks RewriteEngine on RewriteBase /In%20Progress/Vila%20Maninga/ RewriteRule ^page/([a-z|0-9_&;=-]+) index.php?method=page&value=$1 [NC] RewriteRule ^tag/([a-z|0-9_]+) index.php?method=tag&value=$1 [NC] RewriteRule ^search/([a-z|0-9_"]+) index.php?method=search&value=$1 [NC] RewriteRule ^modpage/([con0-9-]+) index.php?method=modpage&value=$1 [NC] RewriteRule ^login index.php?method=login [NC] RewriteRule ^logout index.php?method=logout [NC] RewriteRule ^useraccounts index.php?method=useraccounts [NC]

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  • How to re-prompt after a trap return in bash?

    - by verbose
    I have a script that is supposed to trap SIGTERM and SIGTSTP. This is what I have in the main block: trap 'killHandling' TERM And in the function: killHandling () { echo received kill signal, ignoring return } ... and similar for SIGINT. The problem is one of user interface. The script prompts the user for some input, and if the SIGTERM or SIGINT occurs when the script is waiting for input, it's confusing. Here is the output in that case: Enter something: # SIGTERM received received kill signal, ignoring # shell waits at blank line for user input, user gets confused # user hits "return", which then gets read as blank input from the user # bad things happen because of the blank input I have definitely seen scripts which handle this more elegantly, like so: Enter something: # SIGTERM received received kill signal, ignoring Enter something: # re-prompts user for user input, user is not confused What is the mechanism used to accomplish the latter? Unfortunately I can't simply change my trap code to do the re-prompt as the script prompts the user for several things and what the prompt says is context-dependent. And there has to be a better way than writing context-dependent trap functions. I'd be very grateful for any pointers. Thanks!

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  • What is the difference between calling Stream.Write and using a StreamWriter?

    - by John Nelson
    What is the difference between instantiating a Stream object, such as MemoryStream and calling the memoryStream.Write() method to write to the stream, and instantiating a StreamWriter object with the stream and calling streamWriter.Write()? Consider the following scenario: You have a method that takes a Stream, writes a value, and returns it. The stream is read from later on, so the position must be reset. There are two possible ways of doing it (both seem to work). // Instantiate a MemoryStream somewhere // - Passed to the following two methods MemoryStream memoryStream = new MemoryStream(); // Not using a StreamWriter private static Stream WriteToStream(Stream stream, string value) { stream.Write(Encoding.Default.GetBytes(value), 0, value.Length); stream.Flush(); stream.Position = 0; return stream; } // Using a StreamWriter private static Stream WriteToStreamWithWriter(Stream stream, string value) { StreamWriter sw = new StreamWriter(stream); sw.Write(value, 0, value.Length); sw.Flush(); stream.Position = 0; return stream; } This is partially a scope problem, as I don't want to close the stream after writing to it since it will be read from later. I also certainly don't want to dispose it either, because that will close my stream. The difference seems to be that not using a StreamWriter introduces a direct dependency on Encoding.Default, but I'm not sure that's a very big deal. What's the difference, if any?

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  • Regex: match a non nested code block

    - by Sylvanas Garde
    I am currently writing a small texteditor. With this texteditor users are able to create small scripts for a very simple scripting engine. For a better overview I want to highlight codeblocks with the same command like GoTo(x,y) or Draw(x,y). To achieve this I want to use Regular Expresions (I am already using it to highlight other things like variables) Here is my Expression (I know it's very ugly): /(?<!GoTo|Draw|Example)(^(?:GoTo|Draw|Example)\(.+\)*?$)+(?!GoTo|Draw|Example)/gm It matches the following: lala GoTo(5656) -> MATCH 1 sdsd GoTo(sdsd) --comment -> MATCH 2 GoTo(23329); -> MATCH 3 Test() GoTo(12) -> MATCH 4 LALA Draw(23) -> MATCH 5 Draw(24) -> MATCH 6 Draw(25) -> MATCH 7 But what I want to achieve is, that the complete "blocks" of the same command are matched. In this case Match 2 & 4 and Match 5 & 6 & 7 should be one match. Tested with http://regex101.com/, the programming lanuage is vb.net. Any advise would be very useful, Thanks in advance!

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  • Prove correctness of unit test

    - by Timo Willemsen
    I'm creating a graph framework for learning purposes. I'm using a TDD approach, so I'm writing a lot of unit tests. However, I'm still figuring out how to prove the correctness of my unit tests For example, I have this class (not including the implementation, and I have simplified it) public class SimpleGraph(){ //Returns true on success public boolean addEdge(Vertex v1, Vertex v2) { ... } //Returns true on sucess public boolean addVertex(Vertex v1) { ... } } I also have created this unit tests @Test public void SimpleGraph_addVertex_noSelfLoopsAllowed(){ SimpleGraph g = new SimpleGraph(); Vertex v1 = new Vertex('Vertex 1'); actual = g.addVertex(v1); boolean expected = false; boolean actual = g.addEdge(v1,v1); Assert.assertEquals(expected,actual); } Okay, awesome it works. There is only one crux here, I have proved that the functions work for this case only. However, in my graph theory courses, all I'm doing is proving theorems mathematically (induction, contradiction etc. etc.). So I was wondering is there a way I can prove my unit tests mathematically for correctness? So is there a good practice for this. So we're testing the unit for correctness, instead of testing it for one certain outcome.

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  • Programming Environment for a Motorola 68000 in Linux

    - by Nick Presta
    Greetings all, I am taking a Structure and Application of Microcomputers course this semester and we're programming with the Motorola 68000 series CPU/board. The course syllabus suggests running something like Easy68K or Teesside Motorola 68000 Assembler/Emulator at home to test our programs. I told my prof I run x64 Linux and asked what sort of environment I would need to complete my coursework. He said that the easiest environment to use is a Windows XP 32bit VM with one of the two suggested applications installed, however, he doesn't really care what I use as long as I can test what I write at home. So I'm asking if there exists some sort of emulator or environment for Linux so I can test my code, and what sort of caveats I will run into by writing and testing my code in Linux. Also, I plan to do my editing in Vim, which probably isn't a problem, but I would like any insight into editors for 68000 assembly, if you have any. Thanks! EDIT: Just to clarify - I don't want to install Linux on the board at all - I want to program on my home machine, test the code locally, and then bring it onto the board for grading/running.

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  • Queries within queries: Is there a better way?

    - by mririgo
    As I build bigger, more advanced web applications, I'm finding myself writing extremely long and complex queries. I tend to write queries within queries a lot because I feel making one call to the database from PHP is better than making several and correlating the data. However, anyone who knows anything about SQL knows about JOINs. Personally, I've used a JOIN or two before, but quickly stopped when I discovered using subqueries because it felt easier and quicker for me to write and maintain. Commonly, I'll do subqueries that may contain one or more subqueries from relative tables. Consider this example: SELECT (SELECT username FROM users WHERE records.user_id = user_id) AS username, (SELECT last_name||', '||first_name FROM users WHERE records.user_id = user_id) AS name, in_timestamp, out_timestamp FROM records ORDER BY in_timestamp Rarely, I'll do subqueries after the WHERE clause. Consider this example: SELECT user_id, (SELECT name FROM organizations WHERE (SELECT organization FROM locations WHERE records.location = location_id) = organization_id) AS organization_name FROM records ORDER BY in_timestamp In these two cases, would I see any sort of improvement if I decided to rewrite the queries using a JOIN? As more of a blanket question, what are the advantages/disadvantages of using subqueries or a JOIN? Is one way more correct or accepted than the other?

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  • Django extending user model and displaying form

    - by MichalKlich
    Hello, I am writing website and i`d like to implement profile managment. Basic thing would be to edit some of user details by themself, like first and last name etc. Now, i had to extend User model to add my own stuff, and email address. I am having troubles with displaying form. Example will describe better what i would like achieve. This is mine extended user model. class UserExtended(models.Model): user = models.ForeignKey(User, unique=True) kod_pocztowy = models.CharField(max_length=6,blank=True) email = models.EmailField() This is how my form looks like. class UserCreationFormExtended(UserCreationForm): def __init__(self, *args, **kwargs): super(UserCreationFormExtended, self).__init__(*args, **kwargs) self.fields['email'].required = True self.fields['first_name'].required = False self.fields['last_name'].required = False class Meta: model = User fields = ('username', 'first_name', 'last_name', 'email') It works fine when registering, as i need allow users to put username and email but when it goes to editing profile it displays too many fields. I would not like them to be able to edit username and email. How could i disable fields in form? Thanks for help.

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  • Sql Compact and __sysobjects

    - by Scott Wisniewski
    I have some SQL Compact queries that create tables inside of transaction. This is mainly because I need to simulate temporary tables, which SQL Compact does not support. I do this by creating a real table, and then dropping it at the end of the transaction. This mostly works. Sometimes, however, when creating the tables Sql Compact will try to acquire PAGE level locks on the __sysobjects table. If there are several concurrent queries running that create "temp" tables, the attempt to acquire a page lock can result in a dead lock followed by a SqlLockTimeout exception. For normal tables I could fix this using a "with (rowlock)" hint. However, because I'm not writing the query to insert into __sysobjets (SQL server does that in response to "create table") I can't do this. Does anyone know of a way I could get around this? I've thought about pulling the table creation out of the transaction, but that opens up the possibility of phantom temporary tables that I'd then need to clean up regularly. Ideally I'd like to avoid that if possible.

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