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• Web and stand-alone apps development tendency

  - by Narek

  There is a strong tendency of making web apps and even seems that very soon a lot of features will be available online so that for every day use people will have all necessary software free online and they will not need to install any software locally. Only specific (professional) tools that usually people don’t use at home will not be available as a web app. So my question, how do you imagine selling software that was necessary for everyday use and was not free (seems they can't make money any more by selling their product – no need of those products). And what disadvantages have web apps, that is to say, what is bad to use software online compared with having the same software locally (please list)? Please do not consider this question not connected with programming, as I really would like to have a little statistics from professional programmers who are aware from nowday’s tendency of software and programming. Thanks.

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• MidiSystem.getSequencer() returns Audio Device Unavailable

  - by ksemeks

  I've keep having an exception thrown, on and on. When i try to make a new Sequencer object, i keep getting the javax.sound.midi.MidiUnavailableException: Audio Device Unavailable exception. So, here's the code: import javax.sound.midi.*; public class MiniMusicPlayer1 { public static void main(String[] args) { try { Sequencer sequencer = MidiSystem.getSequencer(); sequencer.open(); Sequence seq = new Sequence(Sequence.PPQ, 4); Track track = seq.createTrack(); for (int i = 5; i < 61; i += 4) { track.add(makeEvent(144, 1, i, 100, i)); track.add(makeEvent(128, 1, i, 100, (i+2))); } sequencer.setSequence(seq); sequencer.setTempoInBPM(220); sequencer.start(); } catch (Exception e) { e.printStackTrace(); } } public static MidiEvent makeEvent(int comd, int chan, int one, int two, int tick) { MidiEvent event = null; try { ShortMessage a = new ShortMessage(); a.setMessage(comd, chan, one, two); event = new MidiEvent(a, tick); } catch (Exception e) { e.printStackTrace(); } return event; } } And here's the complete error (at compile): javax.sound.midi.MidiUnavailableException: Audio Device Unavailable at com.sun.media.sound.MixerSynth.implOpen(MixerSynth.java:165) at com.sun.media.sound.AbstractMidiDevice.doOpen(AbstractMidiDevice.java:144) at com.sun.media.sound.AbstractMidiDevice.openInternal(AbstractMidiDevice.java:134) at com.sun.media.sound.AbstractMidiDevice.getReceiverReferenceCounting(AbstractMidiDevice.java:339) at javax.sound.midi.MidiSystem.getReceiver(MidiSystem.java:243) at javax.sound.midi.MidiSystem.getSequencer(MidiSystem.java:442) at javax.sound.midi.MidiSystem.getSequencer(MidiSystem.java:348) at MiniMusicPlayer1.main(MiniMusicPlayer1.java:9) First i was unable to play MIDI files on my pc, but then i got it to work, so now i can play MIDI files, that's okay. I tried even to close every process which uses my sound card, but the error is still there. Anyone can help me?

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• Erlang Question - Time order of messages

  - by Aiden Bell

  Read (skimmed enough to get coding) through Erlang Programming and Programming Erlang. One question, which is as simple as it sounds: If you have a process Pid1 on machine m1 and a billion million messages are sent to Pid1, are messages handled in parallel by that process (I get the impression no) and(answered below) is there any guarantee of order when processing messages? ie. Received in order sent? If so, how is clock skew handled in high traffic situations for ordering? Coming from the whole C/Thread pools/Shared State background ... I want to get this concrete. I understand distributing an application, but want to ensure the 'raw bones' are what I expect before building processes and distributing workload. Also, am I right in thinking the whole world is currently flicking through Erlang texts ;)

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• Can i use the ordering methods of simple linked lists into a hash list?

  - by Chak

  Im confused with this question? Thank you in advance. Programming in C under linux

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• error msg in avr studio4

  - by shubhang

  i have recently purchased an AVR USB programmer from robokits.co.in, was trying to program atmeg8 using AVR studio4 and i get the following when i click on the program options: a problem occurred when executing the command. make sure u are using the correct programming method. current mode is ISP verify that the device is placed in the correct socket, and that the ISP cable is connected properly.check that the programming frequency specified in the main page is well below 1/4th of the clock frequency of the device. i have tried all that i could think of, i have checked the connections and the freq is below 1/4th of the device. but that doesn't solve this problem i have made the circuit for blinking LEDs program please help me out see the image for details thanking you

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• Too many columns to index - use mySQL Partitions?

  - by Christopher Padfield

  We have an application with a table with 20+ columns that are all searchable. Building indexes for all these columns would make write queries very slow; and any really useful index would often have to be across multiple columns increasing the number of indexes needed. However, for 95% of these searches, only a small subset of those rows need to be searched upon, and quite a small number - say 50,000 rows. So, we have considered using mySQL Partition tables - having a column that is basically isActive which is what we divide the two partitions by. Most search queries would be run with isActive=1. Most queries would then be run against the small 50,000 row partition and be quick without other indexes. Only issue is the rows where isActive=1 is not fixed; i.e. it's not based on the date of the row or anything fixed like that; we will need to update isActive based on use of the data in that row. As I understand it that is no problem though; the data would just be moved from one partition to another during the UPDATE query. We do have a PK on id for the row though; and I am not sure if this is a problem; the manual seemed to suggest the partition had to be based on any primary keys. This would be a huge problem for us because the primary key ID has no basis on whether the row isActive.

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• C# similar technologies and books in Java

  - by MigNix

  Hi, I know this can look like dublicate of other discussions and I have already reviewed them, but they are different. I want to learn Java and I want to know are there any books similar to those that I have seen for C#. Here is the list: C# 4.0 in a Nutshell: The Definitive Reference Probably Java in a Nutshell :) Professional C# 4.0 and .NET 4 Pro C# 2010 and the .NET 4 Platform Accelerated C# 2010 Programming WCF Services Essential Windows Communication Foundation (WCF): For .NET Framework 3.5 C# in Depth: What you need to master C# 2 and 3 CLR via C# Professional ADO.NET 3.5 with LINQ and the Entity Framework Professional Enterprise .NET Framework Design Guidelines: Conventions, Idioms, and Patterns for Reusable .NET Libraries Mainly I am interested in Java 6 and want to know about JVM , Cuncurency, Data access and distributed application technologies. I have seen there are some books on JVM like Inside the Java 2 Virtual Machine also some free books on official web site. Also I found concurrent programming in Java. But may be you can suggest any others. Thank you

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• Are you able to choose the starting tab for a TabBarController?

  - by VOX

  Just doing some programming for iPhone.. is there a method for this?

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• Show me some cool python list comprehensions

  - by christangrant

  One of the major strengths of python and a few other (functional) programming languages are the list comprehension. They allow programmers to write complex expressions in 1 line. They may be confusing at first but if one gets used to the syntax, it is much better than nested complicated for loops. With that said, please share with me some of the coolest uses of list comprehensions. (By cool, I just mean useful) It could be for some programming contest, or a production system. For example: To do the transpose of a matrix mat >>> mat = [ ... [1, 2, 3], ... [4, 5, 6], ... [7, 8, 9], ... ] >>> [[row[i] for row in mat] for i in [0, 1, 2]] [[1, 4, 7], [2, 5, 8], [3, 6, 9]] Please include a description of the expression and where it was used (if possible).

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• Help me understand making maven project w/ non-maven jar dependencies usable by others

  - by deet

  Hi, I'm in the process of learning maven (and java packaging & distribution) with a new oss project I'm making as practice. Here's my situation, all java of course: My main project is ProjectA, maven-based in a github repository. I have also created one utility project, maven-based, in github: ProjectB. ProjectA depends on a project I have heavily modified that originally was from a google-code ant-based repository, ProjectC. So, how do I set up the build for ProjectA such that someone can download ProjectA.jar and use it without needing to install jars for ProjectB and ProjectC, and also how do I set up the build such that someone could check out ProjectA and run only 'mvn package' for a full compile? (Additionally, what should I do with my modified version of ProjectC? include the class files directly into ProjectA, or fork the project into something that could then be used by as a maven dependency?) I've been reading around, links such as this SO question and this SO question, but I'm unclear how those relate to my particular circumstance. So, any help would be appreciated. Thanks!

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• How to prevent onclick statements from being executed?

  - by ryanli

  I want to use an event listener for preventing the onclick statement of a submit button, however, using event.preventDefault() doesn't work as intended. The code is like this: <?xml version="1.0" encoding="utf-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <script type="application/x-javascript"> function addListener() { document.getElementById("submit").addEventListener("click", function(ev) { alert("listener"); ev.preventDefault(); }, false); } </script> <title></title> </head> <body onload="addListener();"> <form id="form" method="post" target=""> <input type="submit" id="submit" onclick="alert('onclick')" value="test" /> </form> </body> </html> The expected behaviour is only "listener" will be alerted, but in practice (Firefox 3.7a5pre), "onclick" and "listener" are both alerted, in the given order. It seems that onclick is being executed before the listener, so event.preventDefault() doesn't work. Is there a way to prevent onclick from being executed?

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• Ajax Update Panel Not Displaying Updated Image in IE, Chrome and FireFox

  - by jmease

  I have a parent page with an Ajax Update Panel that contains an image and a button. There is a hyperlink that opens up a child page. When the child page is submitted, there is an onclientclick event that triggers a javascript function that clicks the button in the update panel on the parent page, the button's click event being the trigger for the panel as well as the event that updates the image URL. When I use this on my android tablet, it works perfectly. However, it doesn't work at all on any browser I've used on a PC (Windows XP). The Image URL updates, but the updated image doesn't display without refreshing the entire page. In IE, I can right click on the image and click Show Image and it updates. In Chrome and Firefox, I have to refresh the entire page. Why would an Ajax control only work properly on the Android OS and what could I be doing wrong that would cause the image not to redisplay on my PC without refreshing the page even though the image URL is clearly being updated properly. I suspect a caching issue, but don't know how to correct.

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• Passing data to a jQuery click() function

  - by jakenoble

  Hi I have a simple span like so <span class="action removeAction">Remove</span> This span is within a table, each row has a remove span. And then I call a URL using AJAX when that span is clicked. The AJAX event needs to know the ID of the object for that row? What is the best way of getting that ID into the click function? I thought I could do something like this <span class="action removeAction" id="1">Remove</span> But an ID should not start with a number? Right? Then I thought I could do <span class="action removeAction" id="my1">Remove</span> Then just strip the 'my' part from the ID, but that just seems Yuk! Below is my click event and where my AJAX event is. <script type="text/javascript" language="text/javascript"> $(document).ready(function() { $(".removeAction").click(function() { //AJAX here that needs to know the ID } }); </script> I am sure there is a nice way of doing this? Thanks. Jake.

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• Is it stable to change I/O direction on microcontroller repeatedly?

  - by SS

  I'm new to microcontroller programming and I have interfaced my microcontroller board to another device that provides a status based on the command send to it but, this status is provided on the same I/O pin that is used to provide data. So basically, I have an 8-bit data line that is used as an output from the microcontroller, but for certain commands I get a status back on one of the data lines if I choose to read it. So I would be required to change the direction of this one line to read the status thus converting this line as an ouput to an input and then back to an output. Is this acceptable programming or will this changing of the I/O pin this frequently cause instability? Thanks.

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• Learning to work with audio in C++

  - by Skilldrick

  My degree was in audio engineering, but I'm fairly new to programming. I'd like to learn how to work with audio in a programming environment, partly so I can learn C++ better through interesting projects. First off, is C++ the right language for this? Is there any reason I shouldn't be using it? I've heard of Soundfile and some other libraries - what would you recommend? Finally, does anyone know of any good tutorials in this subject? I've learnt the basics of DSP - I just want to program it! EDIT: I use Windows. I'd like to play about with real-time stuff, a bit like Max/MSP but with more control.

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• Normalized Device Coordinates to window coordinates

  - by okoman

  I just read some stuff about the theory behind 3d graphics. As I understand it, normalized device coordinates (NDC) are coordinates that describe a point in the interval from -1 to 1 on both the horizontal and vertical axis. On the other hand window coordinates describe a point somewhere between (0,0) and (width,height) of the window. So my formula to convert a point from the NDC coordinate system to the window system would be xwin = width + xndc * 0.5 * width ywin = height + ynfv * 0.5 * height The problem now is that in the OpenGL documentation for glViewport there is an other formula: xwin = ( xndc + 1 ) * width * 0.5 + x ywin = ( yndc + 1 ) * height * 0.5 + y Now I'm wondering what I am getting wrong. Especially I'm wondering what the additional "x" and "y" mean. Hope the question isn't too "not programming related", but I thought somehow it is related to graphics programming.

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• Is Learning the win32 API Worthwhile?

  - by kronoz

  I was certain that somebody would have specifically asked this question, but from what I can see no-one has (there's been a question about learning win32 but that doesn't cover whether it's worthwhile doing so). I am very interested in gaining a deeper understanding of all the systems I use (I mostly program in C#, at least professionally), so I wondered, very simply - is learning win32 worthwhile, or is it overkill? Am I wasting my time? Is the knowledge I'd gain worth the effort? Similar / related questions on StackOverflow: Does it still make sense to learn low level WinAPI programming? How relevant is Win32 programming to modern professionals?

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• AS3---TypeError: Error #1009: Cannot access a property or method of a null object reference

  - by user571620

  I'm very new to flash and I really have no idea what I'm doing. Thank you in advance. its giving me that error after I click a button to go to another frame. After I get the error, some buttons do not go to its destination and instead it just does nothing. The error is as follows: TypeError: Error #1009: Cannot access a property or method of a null object reference. at wmhssports_fla::MainTimeline/frame39() Here is the code for frame 39: stop(); winter_btn.addEventListener(MouseEvent.CLICK, buttonClick1); function buttonClick1(event:MouseEvent):void{ gotoAndPlay(39); }; spring_btn_boys.addEventListener(MouseEvent.CLICK, buttonClick10); function buttonClick10(event:MouseEvent):void{ gotoAndPlay(114); }; fall_btn_boys.addEventListener(MouseEvent.CLICK, buttonClick11); function buttonClick11(event:MouseEvent):void{ gotoAndPlay(135); }; Edit: I could email the file to someone, if they could look at it for me? Its REALLY sketchy due to my inexperience with flash, but then again its not that big of a clip. email me at: [email protected]

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• Performing an action on Parent/Child elements independently.

  - by Matt Weldon

  I have HTML similar to the following in my page <div id="someDiv"> <img src="foo.gif" class="someImg" /> </div> The wrapper div is set up such that when it is clicked, it's background-color changes using the following jQuery code. $("div").click(function(event){ $(this).css("background-color", "blue"); }); I also have some jQuery associated with my img that will do some other function (for the sake of argument I am going to display and alert box) like so: $("img[class=someImg]").click(function(event){ alert("Image clicked"); }); The issue I have come across is that when I click on the img, the event associated with the div is also triggered. I'm pretty sure that this is due to the way that jQuery (or indeed JavaScript) is handling the two DOM elements - clicking the img would require you to also technically click the div, thus triggering both events. Two questions then really: Is my understanding of the DOM/JavaScript flawed in some way or is this actually how things are occurring? Are there any jQuery methods that would allow me to perform actions on a child element without invoking those associated with its parent?

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• Rails - Create if record doesn't exist or else update.....Whats Best way to do this?

  - by ChrisWesAllen

  Hi, I have a create statement for some models but its creating a record within a join table regardless if the record exist. Here is what my code looks like. @user = User.find(current_user) @event = Event.find(params[:id]) for interest in @event.interests @user.choices.create(:interest => interest, :score => 4) end The problem is it creates records no matter what. I would like it to create a record if it doesnt exist, if a record does exist I would just to it to take the attribute of the found record and add or subtract 1. So, I've been looking around and I see something called find_or_create_by. My question is what happens if it finds? Preferably if it finds,I would like to take the current :score attribute and +1. SO is it possible to find or create by id? I'm not sure what attribute I would find by since the model I'm looking at is a join model which only had id foreign keys and the score attribute. I tried @user.choices.find_or_create_by_user(:user => @user.id, :interest => interest, :score => 4) but got "undefined method `find_by_user'".....ANy ideas or help?

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• How to make buttons in python/pygame?

  - by user1334014

  I'm making a game in pygame and on the first screen I want there to be buttons that you can press to (i) start the game, (ii) load a new screen with instructions, and (iii) exit the program. I've found this code online for button making, but I don't really understand it (I'm not that good at object oriented programming). If I could get some explanation as to what it's doing that would be great. Also, when I use it and try to open a file on my computer using the file path, I get the error sh: filepath :Permission denied, which I don't know how to solve. #load_image is used in most pygame programs for loading images def load_image(name, colorkey=None): fullname = os.path.join('data', name) try: image = pygame.image.load(fullname) except pygame.error, message: print 'Cannot load image:', fullname raise SystemExit, message image = image.convert() if colorkey is not None: if colorkey is -1: colorkey = image.get_at((0,0)) image.set_colorkey(colorkey, RLEACCEL) return image, image.get_rect() class Button(pygame.sprite.Sprite): """Class used to create a button, use setCords to set position of topleft corner. Method pressed() returns a boolean and should be called inside the input loop.""" def __init__(self): pygame.sprite.Sprite.__init__(self) self.image, self.rect = load_image('button.png', -1) def setCords(self,x,y): self.rect.topleft = x,y def pressed(self,mouse): if mouse[0] > self.rect.topleft[0]: if mouse[1] > self.rect.topleft[1]: if mouse[0] < self.rect.bottomright[0]: if mouse[1] < self.rect.bottomright[1]: return True else: return False else: return False else: return False else: return False def main(): button = Button() #Button class is created button.setCords(200,200) #Button is displayed at 200,200 while 1: for event in pygame.event.get(): if event.type == MOUSEBUTTONDOWN: mouse = pygame.mouse.get_pos() if button.pressed(mouse): #Button's pressed method is called print ('button hit') if __name__ == '__main__': main() Thank you to anyone who can help me.

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• Is a web-server (e.g servlets) a good solution for an IM server?

  - by John

  I'm looking at a new app, broadly speaking an IM application with a strong client-server model - all communications go through a server so they can be logged centrally. The server will be Java in some form, clients could at this point be anything from a .NET Desktop app to Flex/Silverlight, to a simple web-interface using JS/AJAX. I had anticipated doing the server using standard J2EE so I get a thread-safe, multi-user server for 'free'... to make things simple let's say using Servlets (but in practice SpringMVC would be likely). This all seemed very neat but I'm concerned if the stateless nature of Servlets is the best approach. If my memory of servlets (been a year or two) is right, each time a client sent a HTTP request, typically a new message entered by the user, the servlet could not assume it had the user/chat in memory and might have to get it from the DB... regardless it has to look it up. Then it either has to use some PUSH system to inform other members of the chat, or cache that there are new messages, for other clients who poll the server using AJAX or similar - and when they poll it again has to lookup the chat, including new messages, and send the new data. I'm wondering if a better system would be the server is running core Java, and implements a socket-based communication with clients. This allows much more immediate data transfer and is more flexible if say the IM client included some game you could play. But then you're writing a custom server and sockets don't sound very friendly to a browser-based client on current browsers. Am I missing some big piece of the puzzle here, it kind of feels like I am? Perhaps a better way to ask the question would simply be "if the client was browser-based using HTML/JS and had to run on IE7+,FF2+ (i.e no HTML5), how would you implement the server?" edit: if you are going to suggest using XMPP, I have been trying to get my head around this in another question, so please consider if that's a more appropriate place to discuss this specifically.

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• android.intent.action.NOTIFICATION_REMOVE not available on all devices?

  - by Matt McMinn

  I've got a receiver set up in my android application to catch android.intent.action.NOTIFICATION_REMOVE intents. On my Evo, it works fine - when a notification is cleared from the notification bar, I catch that event and can run some code. I tried running this on a Samsung Moment though, and it is never caught. So now I'm trying to figure out why, and I can't seem to find anything on Google about this intent action - and I set this code up a few months ago, so I don't remember where I even found this action, it doesn't seem to be in the API. The evo is running 2.2, and the moment is running 2.1-update1, so I'm guessing that it's undocumented, and only available in 2.2. Is there any other way to catch an event that a notification has been cleared? Note that I'm not trying to cancel a notification that I put up, or trying to cancel another app's notification, just catch an event when a notification has been cleared. Here's my receiver in AndroidManafest.xml: <receiver android:name=".NotificationClearedReciever"> <intent-filter> <action android:name="android.intent.action.NOTIFICATION_REMOVE" /> </intent-filter> </receiver>

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• Print the next X number of lines in Scala

  - by soulesschild

  Trying to learn Scala using the Programming in Scala book and they have a very basic example for reading lines from a file. I'm trying to expand on it and read a file line by line, look for a certain phrase, then print the next 6 lines following that line if it finds the line. I can write the script easily enough in something like java or Perl but I have no idea how to do it in Scala (probably because I'm not very familiar with the language yet...) Here's the semi adapted sample code from the Programming in Scala book, import scala.io.Source if(args.length>0) { val lines = Source.fromFile(args(0)).getLines().toList for(line<-lines) { if(line.contains("secretPhrase")) { println(line) //How to get the next lines here? } } } else Console.err.println("Pleaseenterfilename")

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• Python as your main language. Possible?

  - by Deinumite

  I am currently attending college and the languages that I will 'know' by graduation are C++ and Java. That being said, i am also in the process of teaching myself Python. I know that every programming language has its own pros and cons, but would it be possible to become a python developer out of school? I always have more 'fun' programming in Python than i do in C++ or Java, and I am also in love with Pythons documentation. I know C++ will always be on top in terms of speed, but what would be the benefit of memorizing every javadoc against focusing on Python instead? are there good jobs to be had with Python? edit: also, would it be beneficial for me to look at C# as well? Microsoft is really throwing their support at it so that could be a decent career path as well.

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