Search Results

Search found 9563 results on 383 pages for 'insertion sort'.

Page 307/383 | < Previous Page | 303 304 305 306 307 308 309 310 311 312 313 314  | Next Page >

• iphone - using NSInvocation: constant value

  - by Mike

  I am dealing with an old iPhone OS 2.x project and I want to keep compatibility, while designing for 3.x. I am using NSInvocation, is a code like this NSInvocation* invoc = [NSInvocation invocationWithMethodSignature: [cell methodSignatureForSelector: @selector(initWithStyle:reuseIdentifier:)]]; [invoc setTarget:cell]; [invoc setSelector:@selector(initWithStyle:reuseIdentifier:)]; int arg2 = UITableViewCellStyleDefault; //???? [invoc setArgument:&arg2 atIndex:2]; [invoc setArgument:&identificadorNormal atIndex:3]; [invoc invoke]; to call 3.0 APIs on 2.0. I am having a problem on the line I marked with question marks. The problem there is that I am trying to assing to arg2, a constant that has not been defined in OS 2.0. As everything with NSInvocation is to do stuff indirectly to avoid compiler errors, how do I set this constant to a variable in an indirect way? Some sort of performSelector "assign value to variable"... is that possible? thanks for any help.

  Read the article

• LINQ query code for complex merging of data.

  - by Stacey

  I've posted this before, but I worded it poorly. I'm trying again with a more well thought out structure. Re-writing this a bit to make it more clear. I have the following code and I am trying to figure out the shorter linq expression to do it 'inline'. Please examine the "Run()" method near the bottom. I am attempting to understand how to join two dictionaries together based on a matching identifier in one of the objects - so that I can use the query in this sort of syntax. var selected = from a in items.List() // etc. etc. select a; This is my class structure. The Run() method is what I am trying to simplify. I basically need to do this conversion inline in a couple of places, and I wanted to simplify it a great deal so that I can define it more 'cleanly'. class TModel { public Guid Id { get; set; } } class TModels : List<TModel> { } class TValue { } class TStorage { public Dictionary<Guid, TValue> Items { get; set; } } class TArranged { public Dictionary<TModel, TValue> Items { get; set; } } static class Repository { static public TItem Single<TItem, TCollection>(Predicate<TItem> expression) { return default(TItem); // access logic. } } class Sample { public void Run() { TStorage tStorage = new TStorage(); // access tStorage logic here. Dictionary<TModel, TValue> d = new Dictionary<TModel, TValue>(); foreach (KeyValuePair<Guid, TValue> kv in tStorage.Items) { d.Add(Repository.Single<TModel, TModels>(m => m.Id == kv.Key),kv.Value); } } }

  Read the article

• How should I implement lazy session creation in PHP?

  - by Adam Franco

  By default, PHP's session handling mechanisms set a session cookie header and store a session even if there is no data in the session. If no data is set in the session then I don't want a Set-Cookie header sent to the client in the response and I don't want an empty session record stored on the server. If data is added to $_SESSION, then the normal behavior should continue. My goal is to implement lazy session creation behavior of the sort that Drupal 7 and Pressflow where no session is stored (or session cookie header sent) unless data is added to the $_SESSION array during application execution. The point of this behavior is to allow reverse proxies such as Varnish to cache and serve anonymous traffic while letting authenticated requests pass through to Apache/PHP. Varnish (or another proxy-server) is configured to pass through any requests without cookies, assuming correctly that if a cookie exists then the request is for a particular client. I have ported the session handling code from Pressflow that uses session_set_save_handler() and overrides the implementation of session_write() to check for data in the $_SESSION array before saving and will write this up as library and add an answer here if this is the best/only route to take. My Question: While I can implement a fully custom session_set_save_handler() system, is there an easier way to get this lazy session creation behavior in a relatively generic way that would be transparent to most applications?

  Read the article

• 4.0/WCF: Best approach for bi-idirectional message bus?

  - by TomTom

  Just a technology update, now that .NET 4.0 is out. I write an application that communicates to the server through what is basically a message bus (instead of method calls). This is based on the internal architecture of the application (which is multi threaded, passing the messages around). There are a limited number of messages to go from the client to the server, quite a lot more from the server to the client. Most of those can be handled via a separate specialized mechanism, but at the end we talk of possibly 10-100 small messages per second going from the server to the client. The client is supposed to operate under "internet conditions". THis means possibly home end users behind standard NAT devices (i.e. typical DSL routers) - a firewalled secure and thus "open" network can not be assumed. I want to have as little latency and as little overhad for the communication as possible. What is the technologally best way to handle the message bus callback? I Have no problem regularly calling to the server for message delivery if something needs to be sent... ...but what are my options to handle the messagtes from the server to the client? WsDualHttp does work how? Especially under a NAT scenario? Just as a note: polling is most likely out - the main problem here is that I would have a significant overhead OR a significant delay, both aren ot really wanted. Technically I would love some sort of streaming appraoch, where the server can write messags to a stream while he generates them and they get sent to the client as they come. Not esure this is doable with WCF, though (if not, I may acutally decide to handle the whole message part outside of WCF and just do control / login / setup / destruction via WCF).

  Read the article

• Adding custom methods to a subclassed NSManagedObject

  - by CJ

  I have a Core Data model where I have an entity A, which is an abstract. Entities B, C, and D inherit from entity A. There are several properties defined in entity A which are used by B, C, and D. I would like to leverage this inheritance in my model code. In addition to properties, I am wondering if I can add methods to entity A, which are implemented in it's sub-entities. For example: I add a method to the interface for entity A which returns a value and takes one argument I add implementations of this method to A, B, C, D Then, I call executeFetchRequest: to retrieve all instances of B I call the method on the objects retrieved, which should call the implementation of the method contained in B's implementation I have tried this, but when calling the method, I receive: [NSManagedObject methodName:]: unrecognized selector sent to instance I presume this is because the objects returned by executeFetchRequest: are proxy objects of some sort. Is there any way to leverage inheritance using subclassed NSManagedObjects? I would really like to be able to do this, otherwise my model code would be responsible for determining what type of NSManagedObject it's dealing with and perform special logic according to the type, which is undesirable. Any help is appreciated, thanks in advance.

  Read the article

• Accessing an excel file throws OleDbException but keeps handle on file

  - by Jonn

  Really odd that I'd get an oledbexception but turns out that the file's handle is still with the original file. I've been searching through google and keep finding the same problem but no solutions. Connection String: "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + filePath + ";" + "Extended Properties=Excel 8.0;"; Note that it works on every other file except a particular excel file. Exception: System.Data.OleDb.OleDbException: No error information available: E_UNEXPECTED(0x8000FFFF). And then I have exception handling like this: try { IEnumerable<string> worksheetNames = GetWorkbookWorksheetNames(connString); DataSet ds; foreach (string worksheetName in worksheetNames) { OleDbDataAdapter dataAdapter = new OleDbDataAdapter("SELECT * FROM [" + worksheetName + "]", connString); ds = new DataSet(); dataAdapter.Fill(ds, "ExcelInfo"); DataTable dt = ds.Tables["ExcelInfo"]; entityList.AddRange(GetDataFromDataTable(dt, worksheetName)); } } catch (OleDbException ex) { File.Move(filePath, filePath + ".invalidFormat.xls"); } Has anyone else encountered this behavior? And I'm not sure how to handle an error that keeps the handle on the file I'm supposed to process. It sort of freezes everything in place.

  Read the article

• MySQL ORDER BY DESC is fast but ASC is very slow

  - by Pepper

  Hello, I'm completely stumped on this one. For some reason when I sort this query by DESC it's super fast, but if sorted by ASC it's extremely slow. This takes about 150 milliseconds: SELECT posts.id FROM posts USE INDEX (published) WHERE posts.feed_id IN ( 4953,622,1,1852,4952,76,623,624,10 ) ORDER BY posts.published DESC LIMIT 0, 50; This takes about 32 seconds: SELECT posts.id FROM posts USE INDEX (published) WHERE posts.feed_id IN ( 4953,622,1,1852,4952,76,623,624,10 ) ORDER BY posts.published ASC LIMIT 0, 50; The EXPLAIN is the same for both queries. id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE posts index NULL published 5 NULL 50 Using where I've tracked it down to "USE INDEX (published)". If I take that out it's the same performance both ways. But the EXPLAIN shows the query is less efficient overall. id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE posts range feed_id feed_id 4 \N 759 Using where; Using filesort And here's the table. CREATE TABLE `posts` ( `id` int(20) NOT NULL AUTO_INCREMENT, `feed_id` int(11) NOT NULL, `post_url` varchar(255) NOT NULL, `title` varchar(255) NOT NULL, `content` blob, `author` varchar(255) DEFAULT NULL, `published` int(12) DEFAULT NULL, `updated` datetime NOT NULL, `created` datetime NOT NULL, PRIMARY KEY (`id`), UNIQUE KEY `post_url` (`post_url`,`feed_id`), KEY `feed_id` (`feed_id`), KEY `published` (`published`) ) ENGINE=InnoDB AUTO_INCREMENT=196530 DEFAULT CHARSET=latin1; Is there a fix for this? Thanks!

  Read the article

• Multiple Table Inheritance vs. Single Table Inheritance in Ruby on Rails

  - by Tony

  I have been struggling for the past few hours thinking about which route I should go. I have a Notification model. Up until now I have used a notification_type column to manage the types but I think it will be better to create separate classes for the types of notifications as they behave differently. Right now, there are 3 ways notifications can get sent out: SMS, Twitter, Email Each notification would have: id subject message valediction sent_people_count deliver_by geotarget event_id list_id processed_at deleted_at created_at updated_at Seems like STI is a good candidate right? Of course Twitter/SMS won't have a subject and Twitter won't have a sent_people_count, valediction. I would say in this case they share most of their fields. However what if I add a "reply_to" field for twitter and a boolean for DM? My point here is that right now STI makes sense but is this a case where I may be kicking myself in the future for not just starting with MTI? To further complicate things, I want a Newsletter model which is sort of a notification but the difference is that it won't use event_id or deliver_by. I could see all subclasses of notification using about 2/3 of the notification base class fields. Is STI a no-brainer, or should I use MTI? Thanks!

  Read the article

• Android - ListActivity, add Header and Footer view

  - by Victor

  I'm using ListActivity, listview. listView = getListView(); just working perfectly. I added footer view as LayoutInflater inflater = getLayoutInflater(); listView.addFooterView( inflater.inflate( R.layout.footer, null ), null, false); and everything was shiny but ugly, so i wanted to add this footer view (which contains only 1 edittext and only 1 button ) to header of listView as LayoutInflater inflater = getLayoutInflater(); listView.addHeaderView( inflater.inflate( R.layout.footer, null ), null, false); and suddenly everything goes wrong, and i get RuntimeException immediately. Suspended(exception RuntimeException) ActivityThread.performLaunchActivity(ActivityThread$ActivityRecord, Intent) ActivityThread.handleLaunchActivity(ActivityThread$ActivityRecord, Intent) ActivityThread.access$2200(ActivityThread, Activity$ActiviyRecord, Intent), so on.. Why is it throws exception ? What is different between addFooterView and addHeaderView, and how can i add Header to ListActivity ? UPDATE So as you can read in comments, my logcat still doesn't work, but i just tried next at this moment: } catch(Exception e){ Writer result = new StringWriter(); PrintWriter printWriter = new PrintWriter(result); e.printStackTrace(printWriter); String error = result.toString(); } and afterward i put breakpoint, and i can read error in expressions section. it said : java.lang.IllegalStateException: Cannot add header view to list -- setAdapter has already been called. it was instructive for all of us. After change sort of commands, it works perferctly.

  Read the article

• Type-conditional controls in Haskell

  - by estanford

  I'm going through the 99 Haskell problems to build my proficiency with the language. On problem 7 ("Flatten a nested list structure"), I found myself wanting to define a conditional behavior based on the type of argument passed to a function. That is, since *Main> :t 1 1 :: (Num t) => t *Main> :t [1,2] [1,2] :: (Num t) => [t] *Main> :t [[1],[2]] [[1],[2]] :: (Num t) => [[t]] (i.e. lists nested at different levels have different data types) it seems like I should be able to write a function that can read the type of the argument, and then behave accordingly. My first attempt was along these lines: listflatten l = do if (:t l) /= ((Num t) => [t]) then listflatten (foldl (++) [] l) else id l But when I try to do that, Haskell returns a parse error. Is Haskell flexible enough to allow this sort of type manipulation, do I need to find another way?

  Read the article

• As a newbie, where should I go if I want to create a small GUI program?

  - by jimbmk

  Hello, I'm a newbie with a little experience writing in BASIC, Python and, of all things, a smidgeon of assembler (as part of a videogame ROM hack). I wanted to create small tool for modifying the hex values at particular points, in a particular file, that would have a GUI interface. What I'm looking for is the ability to create small GUI program, that I can distribute as an EXE (or, at least a standalone directory). I'm not keen on the idea of the .NET languages, because I don't want to force people to download a massive .NET framework package. I currently have Python with IDLE and Boa Constructor set up, and the application runs there. I've tried looking up information on compiling a python app that relies on Wxwidgets, but the search results and the information I've found has been confusing, or just completely incomprehensible. My questions are: Is python a good language to use for this sort of project? If I use Py2Exe, will WxWidgets already be included? Or will my users have to somehow install WxWidgets on their machines? Am I right in thinking at Py2Exe just produces a standalone directory, 'dist', that has the necessary files for the user to just double click and run the application? If the program just relies upon Tkinter for GUI stuff, will that be included in the EXE Py2Exe produces? If so, are their any 'visual' GUI builders / IDEs for Python with only Tkinter? Thankyou for your time, JBMK

  Read the article

• Automatic web form testing/filling

  - by Polatrite

  I recently became lead on getting an inordinate amount of testing done in a very short period of time. We have many different web forms, using custom (Telerik) controls that need to be tested for proper data validation and sensible handling of the data. Some of the forms are several pages long with 30-80 different controls for data entry. I am looking for a software solution (that is free) that would allow me to automate the process of filling in these forms by designing a script, or using a UI. The other requirement is that I can't use any browsers but IE6 (terrible, I know). I have previously used AutoHotkey to great success for automatic Windows form testing, since Autohotkey's API allows you to directly reference controls on the Windows form. However Autohotkey does not have similar support for web forms (everything is just one big "InternetExplorer" control). While I would prefer that I could script some variance in the data to help serialize each test, it's not necessary, as I could go back through and manually edit a field or two (plus "break" whatever control I'm currently testing) to serialize each test. If you've ever seen Spawner: http://forge.mysql.com/projects/project.php?id=214 It's almost exactly the sort of thing I'm looking for (Spawner generates dummy SQL data, as opposed to dummy webform data) - but I won't be picky, I've got a really short deadline to meet and had this thrust in my lap just today. ;) Edit1: One of the challenges of just using Autohotkey to simulate keyboard input (tabbing through controls) is that some controls don't currently have tab index (bug), and some controls cause a page reload after modification, resulting in inconsistent control focus (tabbing screwed up). Our application makes heavy use of page reloads to populate fields (select a location, it auto-populates a city, for example).

  Read the article

• How to catch a carp-warning?

  - by sid_com

  I tried to catch a carp-warning ( carp "$start is $end" if (warnings::enabled()); ) with eval but it didn't work, so I looked in the eval-documentation and I discovered, that eval catches only syntax-errors, run-time-errors or executed die-statements. How could I catch a carp-warning? #!/usr/bin/env perl use warnings; use strict; use 5.012; use List::Util qw(max min); use Number::Range; my @array; my $max = 20; print "Input (max $max): "; my $in = <>; $in =~ s/\s+//g; $in =~ s/(?<=\d)-/../g; eval { my $range = new Number::Range( $in ); @array = sort { $a <=> $b } $range->range; }; if ( $@ =~ /\d+ is > \d+/ ) { die $@ }; # catch the carp-warning doesn't work die "Input greater than $max not allowed $!" if defined $max and max( @array ) > $max; die "Input '0' or less not allowed $!" if min( @array ) < 1; say "@array";

  Read the article

• Simple ASP.NET MVC views without writing a controller

  - by Jake Stevenson

  We're building a site that will have very minimal code, it's mostly just going to be a bunch of static pages served up. I know over time that will change and we'll want to swap in more dynamic information, so I've decided to go ahead and build a web application using ASP.NET MVC2 and the Spark view engine. There will be a couple of controllers that will have to do actual work (like in the /products area), but most of it will be static. I want my designer to be able to build and modify the site without having to ask me to write a new controller or route every time they decide to add or move a page. So if he wants to add a "http://mysite.com/News" page he can just create a "News" folder under Views and put an index.spark page within it. Then later if he decides he wants a /News/Community page, he can drop a community.spark file within that folder and have it work. I'm able to have a view without a specific action by making my controllers override HandleUnknownAction, but I still have to create a controller for each of these folders. It seems silly to have to add an empty controller and recompile every time they decide to add an area to the site. Is there any way to make this easier, so I only have to write a controller and recompile if there's actual logic to be done? Some sort of "master" controller that will handle any requests where there was no specific controller defined?

  Read the article

• Embedding/deploying custom font in .NET app

  - by Swingline Rage

  Is there an official way to distribute (deploy) a specific font with a .NET application? We have a (public domain) "LED font" that prints numbers with the retro LED instrumentface look. This is a standard True Type or Open Type font like any other except it looks funky. Obviously for that to work, this font needs to be on the user's machine. But we'd prefer to not force the user to "install our special font into your font folder". We'd prefer to either load a Font object directly from the TTF, or programatically install the font so it's available. How do applications handle this sort of things? Eg, I notice Adobe XYZ installs various fonts on the system without user intervention. That's what we'd like to do. EDIT: okay, ideally, we'd prefer not to install the font directly. We don't want our nifty themed LED font showing up in the user's font dropdown in MS Word. We'd prefer to use this font, but restrict its use or appearance to our app. Any way to do this? Thanks!

  Read the article

• Need events to execute on timer events, metronome precision.

  - by user295734

  I setup a timer to call an event in my application. The problme is the event execution is being skewed by other windows operations. Ex. openning and window, loading a webpage. I need the event to excute exactly on time, every time. When i first set up the app, used a sound file, like a metronome to listen to the even firing, in a steady state, its firing right on, but as soon do something in the windows environment, the sound fires slower, then sort of sppeds up a bit to catch up. So i added a logging method to the event to ctahc the timer ticks. From that data, it appears that the timer is not being affected by the windows app, but my application event calls are being affected. I figured this out by checking the datetime.now in the event, and if i set it to 250 milliseconds, which is 4 clicks per second. You get data something like below. (sec):(ms) 1:000 1:250 1:500 1:750 2:000 2:250 2:500 2:750 3:000 3:250 3:500 3:750 (lets say i execute some windows event)(time will skew) 4:122 4:388 4:600 4:876 (stop doing what i was doing in windows) (going to shorten the data for simplicit, my list was 30sec long) 5:124 5:268 5:500 5:750 (you would se the time go back the same milliseconds it was at the begining) 6:000 6:250 6:500 6:750 7:000 7:250 7:500 7:750 So i'm thinking the timer continues to fire on the same millisecond every time, but its the event that is being skewed to fire off time by other windows operations. Its not a huge skew, but for what i need to accomplish, its unacceptable. Is there anyhting i can do in .NET, hoping to use XAML/WPF application, thats will correct the skewing of events? thx.

  Read the article

• How to safely let users submit custom themes/plugins for a Rails app

  - by Brian Armstrong

  In my rails app I'd like to let users submit custom "themes" to display data in various ways. I think they can get the data in the view using API calls and I can create an authentication mechanism for this. Also an authenticated API to save data. So this is probably safe. But i'm struggling with the best way to let users upload/submit their own code for the theme. I want this to work sort of like Wordpress themes/plugins where people can upload the thing. But there are some security risks. For example, if I take the uploaded "theme" a user submits and put it in it's own directory somewhere inside the rails app, what are the risks of this? If the user inserts any rails executable code in their theme, even though it's the view they have full access at that point to all the models, everyone's data, etc. Even from other users. So that is not good. I need some way to let the uploaded themes exist in a sandbox of the rails app, but I haven't seen a good way to do this. Any ideas?

  Read the article

• Windows Form color changing

  - by Sef

  Hello, So i am attempting to make a MasterMind program as sort of exercise. Field of 40 picture boxes (line of 4, 10 rows) 6 buttons (red, green, orange, yellow, blue, purple) When i press one of these buttons (lets assume the red one) then a picture box turns red. My question is how do i iterate trough all these picture boxes? I can get it to work but only if i write : And this is offcourse no way to write this, would take me countless of lines that contain basicly the same. private void picRood_Click(object sender, EventArgs e) { UpdateDisplay(); pb1.BackColor = System.Drawing.Color.Red; } Press the red button - first picture box turns red Press the blue button - second picture box turns blue Press the orange button - third picture box turns orange And so on... Ive had a previous similar program that simulates a traffic light, there i could assign a value to each color (red 0, orange 1, green 2). Is something similar needed or how exactly do i adress all those picture boxes and make them correspond to the proper button. Best Regards.

  Read the article

• Java Generic Casting Type Mismatch

  - by Kay

  public class MaxHeap<T extends Comparable<T>> implements Heap<T>{ private T[] heap; private int lastIndex; public void main(String[] args){ int i; T[] arr = {1,3,4,5,2}; //ERROR HERE ******* foo } public T[] Heapsort(T[]anArray, int n){ // build initial heap T[]sortedArray = anArray; for (int i = n-1; i< 0; i--){ //assert: the tree rooted at index is a semiheap heapRebuild(anArray, i, n); //assert: the tree rooted at index is a heap } //sort the heap array int last = n-1; //invariant: Array[0..last] is a heap, //Array[last+1..n-1] is sorted for (int j=1; j<n-1;j++) { sortedArray[0]=sortedArray[last]; last--; heapRebuild(anArray, 0, last); } return sortedArray; } protected void heapRebuild(T[ ] items, int root, int size){ foo } } The error is on the line with "T[arr] = {1,3,4,5,2}" Eclispe complains that there is a: "Type mismatch: cannot convert from int to T" I've tried to casting nearly everywhere but to no avail.A simple way out would be to not use generics but instead just ints but that's sadly not an option. I've got to find a way to resolve the array of ints "{1,3,4,5,2}" into an array of T so that the rest of my code will work smoothly.

  Read the article

• Dependency injection and factory

  - by legenden

  Trying to figure out how to best handle the following scenario: Assume a RequestContext class which has a dependency to an external service, such as: public class RequestContext : IRequestContext { private readonly ServiceFactory<IWeatherService> _weatherService; public RequestContext(ServiceFactory<IWeatherService> weatherService, UserLocation location, string query) { _weatherService = weatherService; ... What sort of dependency should I require in the class that will ultimately instantiate RequestContext? It could be ServiceFactory<IWeatherService>, but that doesn't seem right, or I could create an IRequestContextFactory for it along the lines of: public class RequestContextFactory : IRequestContextFactory { private readonly ServiceFactory<IWeatherService> _weatherService; public RequestContextFactory(ServiceFactory<IWeatherService> weatherService) { _weatherService = weatherService; } public RequestContext Create(UserLocation location, string query) { return new RequestContext(_weatherService, location, query); } } And then pass the IRequestContextFactory through constructor injection. This seems like a good way to do it, but the problem with this approach is that I think it hinders discoverability (devs must know about the factory and implement it, which is not really apparent). Is there a better/more discoverable way that I'm missing?

  Read the article

• Will these optimizations to my Ruby implementation of diff improve performance in a Rails app?

  - by grg-n-sox

  <tl;dr> In source version control diff patch generation, would it be worth it to use the optimizations listed at the very bottom of this writing (see <optimizations>) in my Ruby implementation of diff for making diff patches? </tl;dr> <introduction> I am programming something I have never done before and there might already be tools out there to do the exact thing I am programming but at this point I am having too much fun to care so I am still going to do it from scratch, even if there is a tool for this. So anyways, I am working on a Ruby on Rails app and need a certain feature. Basically I want each entry in a table of mine, let's say for example a table of video games, to have a stored chunk of text that represents a review or something of the sort for that table entry. However, I want this text to be both editable by any registered user and also keep track of different submissions in a version control system. The simplest solution I could think of is just implement a solution that keeps track of the text body and the diff patch history of different versions of the text body as objects in Ruby and then serialize it, preferably in human readable form (so I'll most likely use YAML for this) for editing if needed due to corruption by a software bug or a mistake is made by an admin doing some version editing. So at first I just tried to dive in head first into this feature to find that the problem of generating a diff patch is more difficult that I thought to do efficiently. So I did some research and came across some ideas. Some I have implemented already and some I have not. However, it all pretty much revolves around the longest common subsequence problem, as you would already know if you have already done anything with diff or diff-like features, and optimization the function that solves it. Currently I have it so it truncates the compared versions of the text body from the beginning and end until non-matching lines are found. Then it solves the problem using a comparison matrix, but instead of incrementing the value stored in a cell when it finds a matching line like in most longest common subsequence algorithms I have seen examples of, I increment when I have a non-matching line so as to calculate edit distance instead of longest common subsequence. Although as far as I can tell between the two approaches, they are essentially two sides of the same coin so either could be used to derive an answer. It then back-traces through the comparison matrix and notes when there was an incrementation and in which adjacent cell (West, Northwest, or North) to determine that line's diff entry and assumes all other lines to be unchanged. Normally I would leave it at that, but since this is going into a Rails environment and not just some stand-alone Ruby script, I started getting worried about needing to optimize at least enough so if a spammer that somehow knew how I implemented the version control system and knew my worst case scenario entry still wouldn't be able to hit the server that bad. After some searching and reading of research papers and articles through the internet, I've come across several that seem decent but all seem to have pros and cons and I am having a hard time deciding how well in this situation that the pros and cons balance out. So are the ones listed here worth it? I have listed them with known pros and cons. </introduction> <optimizations> Chop the compared sequences into multiple chucks of subsequences by splitting where lines are unchanged, and then truncating each section of unchanged lines at the beginning and end of each section. Then solve the edit distance of each subsequence. Pro: Changes the time increase as the changed area gets bigger from a quadratic increase to something more similar to a linear increase. Con: Figuring out where to split already seems like you have to solve edit distance except now you don't care how it is changed. Would be fine if this was solvable by a process closer to solving hamming distance but a single insertion would throw this off. Use a cryptographic hash function to both convert all sequence elements into integers and ensure uniqueness. Then solve the edit distance comparing the hash integers instead of the sequence elements themselves. Pro: The operation of comparing two integers is faster than the operation of comparing two strings, so a slight performance gain is received after every comparison, which can be a lot overall. Con: Using a cryptographic hash function takes time to convert all the sequence elements and may end up costing more time to do the conversion that you gain back from the integer comparisons. You could use the built in hash function for a string but that will not guarantee uniqueness. Use lazy evaluation to only calculate the three center-most diagonals of the comparison matrix and then only calculate additional diagonals as needed. And then also use this approach to possibly remove the need on some comparisons to compare all three adjacent cells as desribed here. Pro: Can turn an algorithm that always takes O(n * m) time and make it so only worst case scenario is that time, best case becomes practically linear, and average case is somewhere between the two. Con: It is an algorithm I've only seen implemented in functional programming languages and I am having a difficult time comprehending how to convert this into Ruby based on how it is described at the site linked to above. Make a C module and do the hard work at the native level in C and just make a Ruby wrapper for it so Ruby can make all the calls to it that it needs. Pro: I have to imagine that evaluating something like this in could be a LOT faster. Con: I have no idea how Rails handles apps with ruby code that has C extensions and it hurts the portability of the app. This is an optimization for after the solving of edit distance, but idea is to store additional combined diffs with the ones produced by each version to make a delta-tree data structure with the most recently made diff as the root node of the tree so getting to any version takes worst case time of O(log n) instead of O(n). Pro: Would make going back to an old version a lot faster. Con: It would mean every new commit, the delta-tree would get a new root node that will cost time to reorganize the delta-tree for an operation that will be carried out a lot more often than going back a version, not to mention the unlikelihood it will be an old version. </optimizations> So are these things worth the effort?

  Read the article

• Finding the last focused element

  - by Joshua Cody

  I'm looking to determine which element had the last focus in a series of inputs, that are added dynamically by the user. This code can only get the inputs that are available on page load: $('input.item').focus(function(){ $(this).siblings('ul').slideDown(); }); And this code sees all elements that have ever had focus: $('input.item').live('focus', function(){ $(this).siblings('ul').slideDown(); }); The HTML structure is this: <ul> <li><input class="item" name="goals[]"> <ul> <li>long list here</li> <li>long list here</li> <li>long list here</li> </ul></li> </ul> <a href="#" id="add">Add another</a> On page load, a single input loads. Then with each add another, a new copy of the top unordered list's contents are made and appended, and the new input gets focus. When each gets focus, I'd like to show the list beneath it. But I don't seem to be able to "watch for the most recently focused element, which exists now or in the future." To clarify: I'm not looking for the last occurrence of an element in the DOM tree. I'm looking to find the element that currently has focus, even if said element is not present upon original page load. So in the above image, if I were to focus on the second element, the list of words should appear under the second element. My focus is currently on the last element, so the words are displayed there. Do I have some sort of fundamental assumption wrong?

  Read the article

• JPA/Hibernate query with class name?

  - by Petteri Hietavirta

  In this example com.test.Cat extends com.test.Animal and there is no field DB in CAT table of com.test.Cat explicitly defining its type (it wasn't me). When I query my animals from DB I get a collection of Animals. It is possible to sort them by class name: order by r.class but is there a way to use class name as a criteria? For example I would like to get all animals expect dogs. But no luck - even this does not work: where r.class = ? (String "ccc.test.Cat") as I get an exception: Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer at org.hibernate.type.IntegerType.set(IntegerType.java:64) at org.hibernate.type.NullableType.nullSafeSet(NullableType.java:154) at org.hibernate.type.NullableType.nullSafeSet(NullableType.java:136) at org.hibernate.param.PositionalParameterSpecification.bind(PositionalParameterSpecification.java:62) at org.hibernate.loader.hql.QueryLoader.bindParameterValues(QueryLoader.java:514) at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1589) at org.hibernate.loader.Loader.doQuery(Loader.java:696) at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259) at org.hibernate.loader.Loader.doList(Loader.java:2228) at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2125) at org.hibernate.loader.Loader.list(Loader.java:2120) at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401) at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:361) at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196) at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1148) at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102) at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:67)

  Read the article

• Pattern for limiting number of simultaneous asynchronous calls

  - by hitch

  I need to retrieve multiple objects from an external system. The external system supports multiple simultaneous requests (i.e. threads), but it is possible to flood the external system - therefore I want to be able to retrieve multiple objects asynchronously, but I want to be able to throttle the number of simultaneous async requests. i.e. I need to retrieve 100 items, but don't want to be retrieving more than 25 of them at once. When each request of the 25 completes, I want to trigger another retrieval, and once they are all complete I want to return all of the results in the order they were requested (i.e. there is no point returning the results until the entire call is returned). Are there any recommended patterns for this sort of thing? Would something like this be appropriate (pseudocode, obviously)? private List<externalSystemObjects> returnedObjects = new List<externalSystemObjects>; public List<externalSystemObjects> GetObjects(List<string> ids) { int callCount = 0; int maxCallCount = 25; WaitHandle[] handles; foreach(id in itemIds to get) { if(callCount < maxCallCount) { WaitHandle handle = executeCall(id, callback); addWaitHandleToWaitArray(handle) } else { int returnedCallId = WaitHandle.WaitAny(handles); removeReturnedCallFromWaitHandles(handles); } } WaitHandle.WaitAll(handles); return returnedObjects; } public void callback(object result) { returnedObjects.Add(result); }

  Read the article

• cannot override a concrete member without a third member that's overridden by both

  - by huynhjl

  What does the following error message mean? cannot override a concrete member without a third member that's overridden by both (this rule is designed to prevent ``accidental overrides''); I was trying to do stackable trait modifications. It's a little bit after the fact since I already have a hierarchy in place and I'm trying to modify the behavior without having to rewrite a lot of code. I have a base class called AbstractProcessor that defines an abstract method sort of like this: class AbstractProcessor { def onPush(i:Info): Unit } I have a couple existing traits, to implement different onPush behaviors. trait Pass1 { def onPush(i:Info): Unit = { ... } } trait Pass2 { def onPush(i:Info): Unit = { ... } } So that allows me to use new AbstractProcessor with Pass1 or new AbstractProcessor with Pass2. Now I would like to do some processing before and after the onPush call in Pass1 and Pass2 while minimizing code changes to AbstractProcessor and Pass1 and Pass2. I thought of creating a trait that does something like this: trait Custom extends AbstractProcessor { abstract override def onPush(i:Info): Unit = { // do stuff before super.onPush(i) // do stuff after } And using it with new AbstractProcessor with Pass1 with Custom and I got that error message.

  Read the article

< Previous Page | 303 304 305 306 307 308 309 310 311 312 313 314  | Next Page >