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  • Intelligently removing excess indention from a string

    - by TravisO
    I'm trying to remove some excessive indention from a string, in this case it's SQL, so it can be put into a log file. So I need the find the smallest amount of indention (aka tabs) and remove it from the front of each line, but the following code ends up printing out exactly the same, any ideas? In other words, I want to take the following SELECT blah FROM table WHERE id=1 and convert it to SELECT blah FROM table WHERE id=1 here's the code I tried and fails $sql = ' SELECT blah FROM table WHERE id=1 '; // it's most likely idented SQL, remove any idention $lines = explode("\n", $sql); $space_count = array(); foreach ( $lines as $line ) { preg_match('/^(\t+)/', $line, $matches); $space_count[] = strlen($matches[0]); } $min_tab_count = min($space_count); $place = 0; foreach ( $lines as $line ) { $lines[$place] = preg_replace('/^\t{'. $min_tab_count .'}/', '', $line); $place++; } $sql = implode("\n", $lines); print '<pre>'. $sql .'</pre>';

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  • Runtime of optimized Primehunter

    - by Setton
    Ok so I need some serious runtime help here! This method should take in an int value, check its primality, and return true if the number is indeed a prime. I understand why the loop only needs to go up to i squared, I understand that the worst case scenario is the case in which either the number is prime (or a multiple of a prime). But I don't understand how to quantify the actual runtime. I have done the loop myself by hand to try to understand the pattern or correlation of the number (n) and how many loops occur, but I literally feel like I keep falling into the same trap every time. I need a new way of thinking about this! I have a hint: "Think about the SIZE of the integer" which makes me want to quantify the literal number of integers in a number in relation to how many iterations it does in the for loop (floor log(n)) +1). BUT IT'S NOT WORKIIIING?! I KNOW it isn't square root n, obviously. I'm asking for Big O notation. public class PrimeHunter { public static boolean isPrime(int n) { boolean answer = (n > 1) ? true : false; //runtime = linear runtime for (int i = 2; i * i <= n; i++) //runtime = ????? { if (n % i == 0) //doesn't occur if it is a prime { answer = false; break; } } return answer; //runtime = linear runtime } }

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  • How to terminate a request in JSP (not the "return;")

    - by Genom
    I am programming a website with JSP. There are pages where user must be logged in to see it. If they are not logged in, they should see a login form. I have seen in a php code that you can make a .jsp page (single file), which checkes, whether the user is logged in or not. If not it will show the login form. If the user is logged in, nothing will be done. So in order to do that I use this structure in my JSPs: Headers, menus, etc. etc... normal stuff which would be shown such as body, footer to a logged in user. This structure is very easy to apply to all webpages. So I don't have to apply checking algorithm to each webpage! I can simply add this "" and the page is secure! So my problem is that if the user is not logged in, then only the log in form should be shown and the footer. So code should bypass the body. Therefore structured my checklogin.jsp so: If user is not logged in show the login form and footer and terminate request. The problem is that I don't know how to terminate the request... If I use "return;" then only the checklogin.jsp stops but server continues to process parent page! Therefore page has 2 footers! (1 from parent page and 1 from checklogin.jsp). How can I avoid this? (There is exit(); in php for this by the way!) Thanks for any suggestions!

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  • How (and if) to write a single-consumer queue using the task parallel library?

    - by Eric
    I've heard a bunch of podcasts recently about the TPL in .NET 4.0. Most of them describe background activities like downloading images or doing a computation, using tasks so that the work doesn't interfere with a GUI thread. Most of the code I work on has more of a multiple-producer / single-consumer flavor, where work items from multiple sources must be queued and then processed in order. One example would be logging, where log lines from multiple threads are sequentialized into a single queue for eventual writing to a file or database. All the records from any single source must remain in order, and records from the same moment in time should be "close" to each other in the eventual output. So multiple threads or tasks or whatever are all invoking a queuer: lock( _queue ) // or use a lock-free queue! { _queue.enqueue( some_work ); _queueSemaphore.Release(); } And a dedicated worker thread processes the queue: while( _queueSemaphore.WaitOne() ) { lock( _queue ) { some_work = _queue.dequeue(); } deal_with( some_work ); } It's always seemed reasonable to dedicate a worker thread for the consumer side of these tasks. Should I write future programs using some construct from the TPL instead? Which one? Why?

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  • Handle edittexts onKeyListener ?

    - by hungson175
    Hi everyone, I am creating login screen with 2 editTexts: etUsername and etPassword. On the etUsername, user should input the username and press Enter to go to the edit text etPassword, then he inputs the password, press Enter to login. Here are my current codes: etUsername.setOnKeyListener(new OnKeyListener() { @Override public boolean onKey(View v, int keyCode, KeyEvent event) { if ((keyCode == KeyEvent.KEYCODE_ENTER)) { etPassword.requestFocus(); return true; } else return false; } }); etPassword.setOnKeyListener(new OnKeyListener() { @Override public boolean onKey(View v, int keyCode, KeyEvent event) { if ((keyCode == KeyEvent.KEYCODE_ENTER)) { loginToServer(); return true; } else return false; } }); But when I input the username, and then press Enter – the program tries to log in to the server. In the debug mode, I saw that when I pressed Enter once (on the etUsername) then first: etUsername.onKey() is called and then etPassword.onKey() is also called ! Can anyone please tell me, how to implement what I want ? Thank you very much, Son

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  • Trouble installing R-2.15.2 on Fedora 14

    - by user1896007
    I need to install R-2.15.2, the latest version. I tried using blah> sudo yum install R to install R, but for whatever reason (maybe because it's an old version of Fedora?) my system thinks R version 13 is the most recent. So, I downloaded the .tar.gz file from R's site and used the following: blah> tar -xvf R-2.15.2.tar.gz This successfully unzipped the file. I then ran: blah> ./configure blah/R-2.15.2> ls ChangeLog COPYING Makeconf.in ONEWS src VERSION-NICK config.log doc Makefile.fw OONEWS SVN-REVISION config.site etc Makefile.in po tests configure INSTALL NEWS README tools configure.ac m4 NEWS.pdf share VERSION As you can see, makefiles are present. However, when I run "make" within the R folder, I get the following error: blah/R-2.15.2> make make: No targets specified and no makefile found. Stop. Is there any way I can fix this issue? I'm guessing people will recommend updating Fedora, but is there another way?

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  • session_set_cookie_params on multi-domain sites

    - by nillls
    Hi! I'm currently developing for an application (www.domain.se, .eu) where we're experiencing problems with sessions not propagating across domains. Internet Explorer is the root cause of this, as it will differentiate sessions depending on whether we're typing in "domain.se" or "www.domain.se". Due to some unfortunate redirecting, we're not able to keep the user on the same address the user typed in, instead we're always redirecting to www.domain.se on login. Needless to say, IE users can not login when typing "domain.se". To make this error go away, we implemented a function to try and set the session to be valid across all possible domains by doing the following: if($_SERVER['HTTP_HOST'] == "domain.se") { session_set_cookie_params(3600, '/', '.domain.se', true); } There are basically a few if:s that we go through depending on what address the user typed in, but the third argument stays the same. This, however, results in no-one being able to log in, regardless of domain. I've tried reading up on how session_set_cookie_params() works but to no avail. Any help is greatly appreciated!

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  • Can I use a UINavigationController as the detail view of a UISplitViewController?

    - by B Sweigard
    I'm running into a problem with an iPad app where I would like to have UINavigationControllers in both of the views within a UISplitView. I've looked through other similar questions here, but most link to a tutorial online that doesn't completely solve the problem. Here's a 2-minute walkthrough to re-create the problem I'm having: Create a New Project in XCode, starting from the Split View-based Application template. Add the following NSLog statement as the first line within the DetailViewController's willHideViewController method: NSLog(@"toolbar: %@", toolbar); If you run the application now, the log will show that the DetailViewController's toolbar is alive and well. Now... Open MainWindow.xib and expand the SplitViewController. Drag a Navigation Controller from the library on top of the DetailViewController. Expand the new Navigation Controller and change the class of the UIViewController within to a DetailViewController. Ctrl-drag from the SplitViewController to the DetailViewController and assign it as the delegate. Save MainWindow.xib and run the app again. At this point, the detail view has a navigation bar and an empty toolbar. If you view the logs, you should find that the toolbar is null. Why is this? Am I missing some sort of connection in Interface Builder? Is the navigation bar the problem for some reason? Unlike the tutorial at http://www.cimgf.com/2010/05/24/fixing-the-uisplitviewcontroller-template/, I would like to keep both the navigation bar and the toolbar (preferably with the toolbar at the top when in portrait and not visible when in landscape), so that I still have a functional "Back" button when the iPad is in portrait orientation. Does anyone have any suggestions for fixing this problem? An example project with this sort of set-up would be ideal.

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  • Sanitizing usser input before adding it to the DOM in Javascript

    - by I GIVE TERRIBLE ADVICE
    I'm writing the JS for a chat appication I'm working on in my free time, and I need to have HTML identifiers that change according to user submitted data. This is usually something conceptually shaky enough that I would not even attempt it, but I don't see myself having much of a choice this time. What I need to do then is to escape the HTML id to make sure it won't allow for XSS or breaking HTML. Here's the code: var user_id = escape(id) var txt = '<div class="chut">'+ '<div class="log" id="chut_'+user_id+'"></div>'+ '<textarea id="chut_'+user_id+'_msg"></textarea>'+ '<label for="chut_'+user_id+'_to">To:</label>'+ '<input type="text" id="chut_'+user_id+'_to" value='+user_id+' readonly="readonly" />'+ '<input type="submit" id="chut_'+user_id+'_send" value="Message"/>'+ '</div>'; What would be the best way to escape id to avoid any kind of problem mentioned above? As you can see, right now I'm using the built-in escape() function, but I'm not sure of how good this is supposed to be compared to other alternatives. I'm mostly used to sanitizing input before it goes in a text node, not an id itself.

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  • android service using SystemClock.elapsedRealTime() instead of SystemClock.uptimeMillis() works in emulator but not in samsung captivate ?

    - by Aleadam
    First question here in stackoverflow :) I'm running a little android 2.2 app to log cpu frequency usage. It is set up as a service that will write the data every 10 seconds using a new thread. The code for that part is very basic (see below). It works fine, except that it would not keep track of time while the phone is asleep (which, I know, is the expected behavior). Thus, I changed the code to use SystemClock.elapsedRealTime() instead. Problem is, in emulator both commands are equivalent, but in the phone the app will start the thread but it will never execute the mHandler.postAtTime command. Any advice regarding why this is happening or how to overcome the issue is greatly appreciated. PS: stopLog() is not being called. That's not the problem. mUpdateTimeTask = new Runnable() { public void run() { long millis = SystemClock.uptimeMillis() - mStartTime; int seconds = (int) (millis / 1000); int minutes = seconds / 60; seconds = seconds % 60; String freq = readCPU (); if (freq == null) Toast.makeText(CPU_log_Service.this, "CPU frequency is unreadable.\nPlease make sure the file has read rights.", Toast.LENGTH_LONG).show(); String str = new String ((minutes*60 + seconds) + ", " + freq + "\n"); if (!writeLog (str)) stopLog(); mHandler.postAtTime(this, mStartTime + (((minutes * 60) + seconds + 10) * 1000)); }}; mStartTime = SystemClock.uptimeMillis(); mHandler.removeCallbacks(mUpdateTimeTask); mHandler.postDelayed(mUpdateTimeTask, 100);

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  • Clarification of a some code

    - by Legend
    I have come across a website that appears to use Ajax but does not include any js file except one file called ajax.js which has the following: function run(c, f, b, a, d) { var e = null; if (b && f) { document.getElementById(b).innerHTML = f } if (window.XMLHttpRequest) { e = new XMLHttpRequest() } else { if (window.ActiveXObject) { e = new ActiveXObject(Microsoft.XMLHTTP) } } e.onreadystatechange = function () { if (e.readyState == 4) { if (e.status == 200 || e.statusText == "OK") { if (b) { document.getElementById(b).innerHTML = e.responseText } if (a) { setTimeout(a, 0) } } else { console.log("AJAX Error: " + e.status + " | " + e.statusText); if (b && d != 1) { document.getElementById(b).innerHTML = "AJAX Error. Please try refreshing." } } } }; e.open("GET", c, true); e.setRequestHeader("Content-Type", "application/x-www-form-urlencoded"); e.send(null) } Like you might have guessed, the way it issues queries inside the page with queries like this: run('page.php',loadingText,'ajax-test', 'LoadSamples()'); I must admit that this is the first time I've seen a page from which I could not figure how things are being done. I have a few questions: Is this Server-Side Ajax or something similar? If not, can someone clarify what exactly is this? Why does one use this? Is it for hiding the design details? (which are otherwise revealed in plain text by javascript) How difficult would it be to convert my existing application into this design pattern? (maybe a subjective question but any short suggestion will do) Any suggestions?

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  • Sanitizing user input before adding it to the DOM in Javascript

    - by I GIVE TERRIBLE ADVICE
    I'm writing the JS for a chat application I'm working on in my free time, and I need to have HTML identifiers that change according to user submitted data. This is usually something conceptually shaky enough that I would not even attempt it, but I don't see myself having much of a choice this time. What I need to do then is to escape the HTML id to make sure it won't allow for XSS or breaking HTML. Here's the code: var user_id = escape(id) var txt = '<div class="chut">'+ '<div class="log" id="chut_'+user_id+'"></div>'+ '<textarea id="chut_'+user_id+'_msg"></textarea>'+ '<label for="chut_'+user_id+'_to">To:</label>'+ '<input type="text" id="chut_'+user_id+'_to" value='+user_id+' readonly="readonly" />'+ '<input type="submit" id="chut_'+user_id+'_send" value="Message"/>'+ '</div>'; What would be the best way to escape id to avoid any kind of problem mentioned above? As you can see, right now I'm using the built-in escape() function, but I'm not sure of how good this is supposed to be compared to other alternatives. I'm mostly used to sanitizing input before it goes in a text node, not an id itself.

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  • Trouble accessing Mutable array

    - by Jared Gross
    Im having trouble with my for loop where I am trying to index user names. I am able to separate my original array into individual objects but am not able to send the value to a new array that I need to reference later on. The value and count for userNames in my self.userNamesArray = userNames; line is correct. But right after that when I log self.userNamesArray, I get (null). Any tips cause I'm not completely sure I'm cheers! .h @property (nonatomic, copy) NSMutableArray *userNamesArray; .m - (void)viewWillAppear:(BOOL)animated { self.friendsRelation = [[PFUser currentUser] objectForKey:@"friendsRelation"]; PFQuery *query = [self.friendsRelation query]; [query orderByAscending:@"username"]; [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) { if (error) { NSLog(@"Error: %@ %@", error, [error userInfo]); } else { self.friends = objects; NSArray *users = [self.friends valueForKey:@"username"]; NSLog(@"username:%@", users); //Create an array of name wrappers and pass to the root view controller. NSMutableArray *userNames = [[NSMutableArray alloc] initWithCapacity:[self.friends count]]; for (NSString *user in users) { componentsSeparatedByCharactersInSet:charSet]; NSArray *nameComponents = [user componentsSeparatedByString:@" "]; UserNameWrapper *userNameWrapper = [[UserNameWrapper alloc] initWithUserName:nil nameComponents:nameComponents]; [userNames addObject:userNameWrapper]; } self.userNamesArray = userNames; NSLog(@"userNamesArray:%@",self.userNamesArray); [self.tableView reloadData]; } Here's the code where I need to reference the self.userNamesArray where again, it is comping up nil. - (void)setUserNamesArray:(NSMutableArray *)newDataArray { if (newDataArray != self.userNamesArray) { self.userNamesArray = [newDataArray mutableCopy]; if (self.userNamesArray == nil) { self.sectionsArray = nil; NSLog(@"user names empty"); } else { [self configureSections]; } } }

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  • SQLite3 database doesn't actually insert data - iPhone

    - by user334934
    I'm trying to add a new entry into my database, but it's not working. There are no errors thrown, and the code that is supposed to be executed after the insertion runs, meaning there are no errors with the query. But still, nothing is added to the database. I've tried both prepared statements and the simpler sqlite3_exec and it's the same result. I know my database is being loaded because the info for the tableview (and subsequent tableviews) are loaded from the database. The connection isn't the problem. Also, the log of the sqlite3_last_insert_rowid(db) returns the correct number for the next row. But still, the information is not saved. Here's my code: db = [Database openDatabase]; NSString *query = [NSString stringWithFormat:@"INSERT INTO lists (name) VALUES('%@')", newField.text]; NSLog(@"Query: %@",query); sqlite3_stmt *statement; if (sqlite3_prepare_v2(db, [query UTF8String], -1, &statement, nil) == SQLITE_OK) { if(sqlite3_step(statement) == SQLITE_DONE){ NSLog(@"You created a new list!"); int newListId = sqlite3_last_insert_rowid(db); MyList *newList = [[MyList alloc] initWithName:newField.text idNumber:[NSNumber numberWithInt:newListId]]; [self.listArray addObject:newList]; [newList release]; [self.tableView reloadData]; sqlite3_finalize(statement); } else { NSAssert1(0, @"Error while inserting data. '%s'", sqlite3_errmsg(db)); } } [Database closeDatabase:db]; Again, no errors have been thrown. The prepare and step statements return SQLITE_OK and SQLITE_DONE respectively, yet nothing happens. Any help is appreciated!

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  • Time.new does not work as I would expect

    - by Marius Pop
    I am trying to generate some seed material. seed_array.each do |seed| Task.create(date: Date.new(2012,06,seed[1]), start_t: Time.new(2012,6,2,seed[2],seed[3]), end_t: Time.new(2012,6,2,seed[2] + 2,seed[3]), title: "#{seed[0]}") end Ultimately I will put random hours, minutes, seconds. The problem that I am facing is that instead of creating a time with the 2012-06-02 date it creates a time with a different date: 2000-01-01. I tested Time.new(2012,6,2,2,20,45) in rails console and it works as expected. When I am trying to seed my database however some voodo magic happens and I don't get the date I want. Any inputs are appreciated. Thank you! Update1: * [1m[36m (0.0ms)[0m [1mbegin transaction[0m [1m[35mSQL (0.5ms)[0m INSERT INTO "tasks" ("created_at", "date", "description", "end_t", "group_id", "start_t", "title", "updated_at") VALUES (?, ?, ?, ?, ?, ?, ?, ?) [["created_at", Tue, 03 Jul 2012 02:15:34 UTC +00:00], ["date", Thu, 07 Jun 2012], ["description", nil], ["end_t", 2012-06-02 10:02:00 -0400], ["group_id", nil], ["start_t", 2012-06-02 08:02:00 -0400], ["title", "99"], ["updated_at", Tue, 03 Jul 2012 02:15:34 UTC +00:00]] [1m[36m (2.3ms)[0m [1mcommit transaction * This is a small sample of the log. Update 2 Task id: 101, date: "2012-06-26", start_t: "2000-01-01 08:45:00", end_t: "2000-01-01 10:45:00", title: "1", description: nil, group_id: nil, created_at: "2012-07-03 02:15:33", updated_at: "2012-07-03 02:15:33" This is what shows up in rails console.

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  • CakePHP: Missing database table

    - by Justin
    I have a CakePHP application that is running fine locally. I uploaded it to a production server and the first page that uses a database connection gives the "Missing Database Table" error. When I look at the controller dump, it's complaining about the first table. I've tried a variety of things to fix this problem, with no luck: I've confirmed that at the command line I can login with the given MySQL credentials in database.php I've confirmed this table exists I've tried using the MySQL root credentials (temporarily) to see if the problem lies with permissions of the user. The same error appeared. My debug level is currently set to 3 I've deleted the entire contents of /app/tmp/cache I've set 777 permissions on /app/tmp* I've confirmed that I can run DESCRIBE commands at the commant line MySQL when logged in with the MySQL credentials used by by the application I've verified that the CakePHP log file only contains the error I'm setting in the browser window. I've tried all the suggestions I could find in similar postings on SO I've Googled around and didn't find any other ideas I think I've eliminating the obvious problems and my research isn't turning anything up. I feel like I'm missing something obvious. Any ideas?

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  • Load image blurred Android

    - by Mira
    I'm trying to create a map for a game through an image, where each black pixel is equivalent to a wall, and yellow to flowers(1) and green grass(0) so far i had this image (50x50): http://i.imgur.com/Ydj9Cp2.png the problem here seems to be that, when i read the image on my code, it get's scaled up to 100x100, even tough i have it on the raw folder. I can't let it scale up or down because that will put noise and blur on the image and then the map won't be readable. here i have my code: (...) Bitmap tab=BitmapFactory.decodeResource(resources, com.example.lolitos2.R.raw.mappixel); //tab=Bitmap.createScaledBitmap(tab, 50, 50, false); Log.e("w", tab.getWidth()+"."+tab.getHeight()); for (int i = 0; i < tab.getWidth(); i++) { for (int j = 0; j < tab.getHeight(); j++) { int x = j; int y = i; switch (tab.getPixel(x, y)) { // se o é uma parede case Color.BLACK: getParedes()[x][y] = new Parede(x, y); break; case Color.GREEN: fundo.add(new Passivo(x,y,0)); break; default: fundo.add(new Passivo(x,y,1)); } } } How can i read my image Map without rescaling it?

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  • Is there any good reason for private methods existence in C# (and OOP in general)?

    - by Piotr Lopusiewicz
    I don't mean to troll but I really don't get it. Why would language designers allow private methods instead of some naming convention (see __ in Python) ? I searched for the answer and usual arguments are: a) To make the implementation cleaner/avoid long vertical list of methods in IDE autocompletion b) To announce to the world which methods are public interface and which may change and are just for implementation purpose c) Readability Ok so now, all of those could be achieved by naming all private methods with __ prefix or by "private" keyword which doesn't have any implications other than be information for IDE (don't put those in autocompletion) and other programers (don't use it unless you really must). Hell, one could even require unsafe-like keyword to access private methods to really discourage this. I am asking this because I work with some c# code and I keep changing private methods to public for test purposes as many in-between private methods (like string generators for xml serialization) are very useful for debugging purposes (like writing some part of string to log file etc.). So my question is: Is there anything which is achieved by access restriction but couldn't be achieved by naming conventions without restricting the access ?

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  • Can't grab foreign key during after_create callback because it doesn't exist yet!

    - by Randy
    I have some models all linked together in memory (parent:child:child:child) and saved at the same time by saving the top-most parent. This works fine. I'd like to tap into the after_create callback of one of the children to populate a changelog table. One of the attributes I need to copy/push into the changelog table is the child's foreign_key to it's direct parent, but it doesn't exist at the time after_create fires!?! Without the after_create callback, I can look in the log and see that the child is being saved before it's parent (foreign key blank) then the parent is inserted... then the child is updated with the id from the parent. The child's after_create is firing at the right time, but it happens before Rails has had a chance to update the child with the foreign_key. Is there any way to force Rails to save such a linkage of models in a certain order? ie.parent, then child (parent foreign_key exists), then that child's child (again, foreign_key is accessible) etc. ?? If not, how would I have my routine fire after a record is created AND get the foreign_key? Seems a callback like this would be helpful: after_create_with_foreign_keys

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  • Java: GatheringByteChannel advantages?

    - by Jason S
    I'm wondering when the GatheringByteChannel's write methods (taking in an array of ByteBuffers) have advantages over the "regular" WritableByteChannel write methods. I tried a test where I could use the regular vs. the gathering write method on a FileChannel, with approx 400KB/sec total in ByteBuffers of between 23-27 bytes in length in both cases. Gathering writes used an array of 64. The regular method used up approx 12% of my CPU, and the gathering method used up approx 16% of my CPU (worse than the regular method!) This tells me it's NOT useful to use gathering writes on a FileChannel around this range of operating parameters. Why would this be the case, and when would you ever use GatheringByteChannel? (on network I/O?) Relevant differences here: public void log(Queue<Packet> packets) throws IOException { if (this.gather) { int Nbuf = 64; ByteBuffer[] bbufs = new ByteBuffer[Nbuf]; int i = 0; Packet p; while ((p = packets.poll()) != null) { bbufs[i++] = p.getBuffer(); if (i == Nbuf) { this.fc.write(bbufs); i = 0; } } if (i > 0) { this.fc.write(bbufs, 0, i); } } else { Packet p; while ((p = packets.poll()) != null) { this.fc.write(p.getBuffer()); } } }

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  • Given a 2d array sorted in increasing order from left to right and top to bottom, what is the best w

    - by Phukab
    I was recently given this interview question and I'm curious what a good solution to it would be. Say I'm given a 2d array where all the numbers in the array are in increasing order from left to right and top to bottom. What is the best way to search and determine if a target number is in the array? Now, my first inclination is to utilize a binary search since my data is sorted. I can determine if a number is in a single row in O(log N) time. However, it is the 2 directions that throw me off. Another solution I could use, if I could be sure the matrix is n x n, is to start at the middle. If the middle value is less than my target, then I can be sure it is in the left square portion of the matrix from the middle. I then move diagnally and check again, reducing the size of the square that the target could potentially be in until I have honed in on the target number. Does anyone have any good ideas on solving this problem? Example array: Sorted left to right, top to bottom. 1 2 4 5 6 2 3 5 7 8 4 6 8 9 10 5 8 9 10 11

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  • null reference problems with c#

    - by alex
    Hi: In one of my window form, I created an instance of a class to do some works in the background. I wanted to capture the debug messages in that class and displayed in the textbox in the window form. Here is what I did: class A //window form class { public void startBackGroundTask() { B backGroundTask = new B(this); } public void updateTextBox(string data) { if (data != null) { if (this.Textbox.InvokeRequired) { appendUIDelegate updateDelegate = new appendUIDelegate(updateUI); try { this.Invoke(updateDelegate, data); } catch (Exception e) { Console.WriteLine(e.Message); } } else { updateUI(data); } } } private void updateUI(string data) { if (this.Textbox.InvokeRequired) { this.Textbox.Invoke(new appendUIDelegate(this.updateUI), data); } else { //update the text box this.Textbox.AppendText(data); this.Textbox.AppendText(Environment.NewLine); } } private delegate void appendUIDelegate(string data); } class B // background task { A curUI; public b( A UI) { curUI = UI; } private void test() { //do some works here then log the debug message to UI. curUI.updateTextBox("message); } } I keep getting a null reference exception after this.Invoke(updateDelegate, data); is called. I know passing "this" as a parameter is strange. But I want to send the debug message to my window form. Please help. Thanks

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  • Same function on multiple div classes doesn't work

    - by Sebass van Boxel
    I'm doing something terribly wrong and just can't find the solution for it. Situation: I've got a number of products with a number of quotes per product. Those quote automatically scroll in a div. If the scroll reaches the last quote is scroll back to the first one. What works: The function basically works when it's applied on 1 div, but when applied on multiple div it doesn't scroll back to the first one or keeps scrolling endlessly. This is the function i've written for this: function quoteSlide(divname){ $total = ($(divname+" > div").size()) $width = $total * 160; $(divname).css('width', ($width)); console.log ($totalleft *-1); if ($width - 160 > $totalleft *-1){ $currentleft = $(divname).css('left'); $step = -160; $totalleft = parseInt($currentleft)+$step; }else{ $totalleft = 0; } $(divname).animate(     { left: $totalleft }, // what we are animating     'slow', // how fast we are animating     'swing', // the type of easing     function() { // the callback }); } It's being executed by something like: quoteSlide('#quotecontainer_1'); in combination with a setInterval so it keeps scrolling automatically. This is the jsFiddle where it goes wrong (So applied on more than 1 div) http://jsfiddle.net/FsrbZ/. This is the jsFiddle where everything goes okay. (applied on 1 div) When changing the following: quoteSlide('#quotecontainer_1'); quoteSlide('#quotecontainer_2'); setInterval(function() { quoteSlide('#quotecontainer_1'); quoteSlide('#quotecontainer_2'); }, 3400);? to quoteSlide('#quotecontainer_1'); setInterval(function() { quoteSlide('#quotecontainer_1'); }, 3400);? it does work... but only on 1 quotecontainer.

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  • Log4j Logging to the Wrong Directory

    - by John
    I have a relatively complex log4j.xml configuration file with many appenders. Some machines the application runs on need a separate log directory, which is actually a mapped network drive. To get around this, we embed a system property as part of the filename in order to specify the directory. Here is an example: The "${user.dir}" part is set as a system property on each system, and is normally set to the root directory of the application. On some systems, this location is not the root of the application. The problem is that there is always one appender where this is not set, and the file appears not to write to the mapped drive. The rest of the appenders do write to the correct location per the system property. As a unit test, I set up our QA lab to hard-code the values for the appender above, and it worked: however, a different appender will then append to the wrong file. The mis-logged file is always the same for a given configuration: it is not a random file each time. My best educated guess is that there is a HashMap somewhere containing these appenders, and for some reason, the first one retrieved from the map does not have the property set. Our application does have custom system properties loading: the main() method loads a properties file and calls into System.setProperties(). My first instinct was to check the static initialization order, and to ensure the controller class with the main method does not call into log4j (directly or indirectly) before setting the properties just in case this was interfering with log4j's own initialization. Even removing all vestiges of log4j from the initialization logic, this error condition still occurs.

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  • What guarantees are there on the run-time complexity (Big-O) of LINQ methods?

    - by tzaman
    I've recently started using LINQ quite a bit, and I haven't really seen any mention of run-time complexity for any of the LINQ methods. Obviously, there are many factors at play here, so let's restrict the discussion to the plain IEnumerable LINQ-to-Objects provider. Further, let's assume that any Func passed in as a selector / mutator / etc. is a cheap O(1) operation. It seems obvious that all the single-pass operations (Select, Where, Count, Take/Skip, Any/All, etc.) will be O(n), since they only need to walk the sequence once; although even this is subject to laziness. Things are murkier for the more complex operations; the set-like operators (Union, Distinct, Except, etc.) work using GetHashCode by default (afaik), so it seems reasonable to assume they're using a hash-table internally, making these operations O(n) as well, in general. What about the versions that use an IEqualityComparer? OrderBy would need a sort, so most likely we're looking at O(n log n). What if it's already sorted? How about if I say OrderBy().ThenBy() and provide the same key to both? I could see GroupBy (and Join) using either sorting, or hashing. Which is it? Contains would be O(n) on a List, but O(1) on a HashSet - does LINQ check the underlying container to see if it can speed things up? And the real question - so far, I've been taking it on faith that the operations are performant. However, can I bank on that? STL containers, for example, clearly specify the complexity of every operation. Are there any similar guarantees on LINQ performance in the .NET library specification?

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