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  • Find all A^x in a given range

    - by Austin Henley
    I need to find all monomials in the form AX that when evaluated falls within a range from m to n. It is safe to say that the base A is greater than 1, the power X is greater than 2, and only integers need to be used. For example, in the range 50 to 100, the solutions would be: 2^6 3^4 4^3 My first attempt to solve this was to brute force all combinations of A and X that make "sense." However this becomes too slow when used for very large numbers in a big range since these solutions are used in part of much more intensive processing. Here is the code: def monoSearch(min, max): base = 2 power = 3 while 1: while base**power < max: if base**power > min: print "Found " + repr(base) + "^" + repr(power) + " = " + repr(base**power) power = power + 1 base = base + 1 power = 3 if base**power > max: break I could remove one base**power by saving the value in a temporary variable but I don't think that would make a drastic effect. I also wondered if using logarithms would be better or if there was a closed form expression for this. I am open to any optimizations or alternatives to finding the solutions.

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  • Memory increases with Java UDP Server

    - by Trevor
    I have a simple UDP server that creates a new thread for processing incoming data. While testing it by sending about 100 packets/second I notice that it's memory usage continues to increase. Is there any leak evident from my code below? Here is the code for the server. public class UDPServer { public static void main(String[] args) { UDPServer server = new UDPServer(15001); server.start(); } private int port; public UDPServer(int port) { this.port = port; } public void start() { try { DatagramSocket ss = new DatagramSocket(this.port); while(true) { byte[] data = new byte[1412]; DatagramPacket receivePacket = new DatagramPacket(data, data.length); ss.receive(receivePacket); new DataHandler(receivePacket.getData()).start(); } } catch (IOException e) { e.printStackTrace(); } } } Here is the code for the new thread that processes the data. For now, the run() method doesn't do anything. public class DataHandler extends Thread { private byte[] data; public DataHandler(byte[] data) { this.data = data; } @Override public void run() { System.out.println("run"); } }

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  • Sheet and thread memory problem

    - by Xident
    Hi Guys, recently I started a project which can export some precalculated Grafix/Audio to files, for after processing. All I was doing is to put a new Window (with progressindicator and an Abort Button) in my main xib and opened it using the following code: [NSApp beginSheet: REC_Sheet modalForWindow: MOTHER_WINDOW modalDelegate: self didEndSelector: nil contextInfo: nil]; NSModalSession session=[NSApp beginModalSessionForWindow:REC_Sheet]; RECISNOTDONE=YES; while (RECISNOTDONE) { if ([NSApp runModalSession:session]!=NSRunContinuesResponse) break; usleep(100); } [NSApp endModalSession:session]; A Background Thread (pthread) was started earlier, to actually perform the work and save all the targas/wave file. Which worked great, but after an amount of time, it turned out that the main thread was not responding anymore and my memory footprint raised unstoppable. I tried to debug it with Instruments, and saw a lot of CFHash etc stuff growing to infinity. By accident i clicked below the sheet, and temporary it helped, the main thread (AppKit ?) was releasing it's stuff, but just for a little time. I can't explain it to me, first of all I thought it was the access from my thread to the Progressbar to update the Progress (intervalled at 0,5sec), so I cut it out. But even if I'm not updating anything and did nothing with the Progressbar, my Application eat up all the Memory, because of not releasing it's "Main-Event" or whatsoever Stuff. Is there any possibility to "drain" this Main thread Memory stuff (Runloop / NSApp call?). And why the heck doesn't the Main thread respond anymore (after this simple task) ??? I don't have a clou anymore, please help ! Thanks in advance ! P.S. How do you guys implement "threaded long task" Stuff and updating your gui ???

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  • Learning Java and logic using debugger. Did I cheat?

    - by centr0
    After a break from coding in general, my way of thinking logically faded (as if it was there to begin with...). I'm no master programmer. Intermediate at best. I decided to see if i can write an algorithm to print out the fibonacci sequence in Java. I got really frustrated because it was something so simple, and used the debugger to see what was going on with my variables. solved it in less than a minute with the help of the debugger. Is this cheating? When I read code either from a book or someone else's, I now find that it takes me a little more time to understand. If the alghorithm is complex (to me) i end up writing notes as to whats going on in the loop. A primitive debugger if you will. When you other programmers read code, do you also need to write things down as to whats the code doing? Or are you a genius and and just retain it?

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  • How can I use Perl to determine whether the contents of two files are identical?

    - by Zaid
    This question comes from a need to ensure that changes I've made to code doesn't affect the values it outputs to text file. Ideally, I'd roll a sub to take in two filenames and return 1or return 0 depending on whether the contents are identical or not, whitespaces and all. Given that text-processing is Perl's forté, it should be quite easy to compare two files and determine whether they are identical or not (code below untested). use strict; use warnings; sub files_match { my ( $fileA, $fileB ) = @_; open my $file1, '<', $fileA; open my $file2, '<', $fileB; while (my $lineA = <$file1>) { next if $lineA eq <$file2>; return 0 and last; } return 1; } The only way I can think of (sans CPAN modules) is to open the two files in question, and read them in line-by-line until a difference is found. If no difference is found, the files must be identical. But this approach is limited and clumsy. What if the total lines differ in the two files? Should I open and close to determine line count, then re-open to scan the texts? Yuck. I don't see anything in perlfaq5 relating to this. I want to stay away from modules unless they come with the core Perl 5.6.1 distribution.

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  • Need help with transferring data between MySQL db's using PHP

    - by JM4
    In one of the sites I manage, the client has decided to take on ACH/Bank Account administration where it was previously outsourced. As a result, the information submitted in our online form which used to simply store in a single database for processing now must sit in 'limbo' until the funds used for payment have been verified. My original plan is as follows: At the end of an enrollment, all form data is collected and stored in a single MySQL database. Our internal administrator will receive an email notification reminding him enrollments have taken place. He will process the ACH information collected and wait the 3-4 business days needed for payment to clear. Once the payment information has been returned as Good (haven't considered what I will do with the 'bad' yet), the administrator can log into a secure portal which allows him to click a button to 'process' the full information once compared and verified. the process is simplified as: Enrollment complete: data stored in DB 'A' Funds verified and link clicked: data from 'A' is copied to DB 'B' and 'A' is deleted. I have run similar processes with CSV output before and simply used //transfers old data to archive $transfer = mysql_query('INSERT INTO '.$archive.' SELECT * FROM '.$table) or die(mysql_error()); //empties existing table $query = mysql_query('TRUNCATE TABLE '.$table) or die(mysql_error()); but in those cases, ALL data returned was copied and deleted. I only want to copy and delete a single record. Any idea how to accomplish this?

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  • Python : How do you find the CPU consumption for a piece of code?

    - by Yugal Jindle
    Background: I have a django application, it works and responds pretty well on low load, but on high load like 100 users/sec, it consumes 100% CPU and then due to lack of CPU slows down. Problem : Profiling the application gives me time taken by functions. This time increases on high load. Time consumed may be due to complex calculation or for waiting for CPU. so, how to find the CPU cycles consumed by a piece of code ? Since, reducing the CPU consumption will increase the response time. I might have written extremely efficient code and need to add more CPU power OR I might have some stupid code taking the CPU and causing the slow down ? Any help is appreciated ! Update: I am using Jmeter to profile my webapp, it gives me a throughput of 2 requests/sec. [ 100 users] I get a average time of 36 seconds on 100 request vs 1.25 sec time on 1 request. More Info Configuration Nginx + Uwsgi with 4 workers No database used, using a responses from a REST API On 1st hit the response of REST API gets cached, therefore doesn't makes a difference. Using ujson for json parsing. Curious to Know: Python-Django is used by so many orgs for so many big sites, then there must be some high end Debug / Memory-CPU analysis tools. All those I found were casual snippets of code that perform profiling.

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  • lightbox dynamic image retrieval

    - by GSTAR
    I am constructing a lighbox gallery, currently experimenting with FancyBox (http://fancybox.net) and ColorBox (http://colorpowered.com/colorbox). By default you have to include a link to the large version of the image so that the Lightbox can display it. However, I am wanting to have the image link URLs pointing to a script rather than directly to the image file. So for example, instead of: <a href="mysite/images/myimage.jpg"> I want to do: <a href="mysite/photos/view/abc123"> The above URL points to a function: public function actionPhotos($view) { $photo=Photo::model()->find('name=:name', array(':name'=>$view)); if(!empty($photo)) { $user=$photo->user; $this->renderPartial('_photo', array('user'=>$user, 'photo'=>$photo, true)); } } At some point in the future the function will also update the view count of the image. Now this approach is working to an extent - most images load up but some do not load up (the lightbox gets displayed in a malformed state). I think the reason for this is because it is not processing the function quick enough. For example when I click the "next" button it needs to go to the URL, process the function and retreive/output the response. Does anybody know how I can get this working properly?

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  • When to use CTEs to encapsulate sub-results, and when to let the RDBMS worry about massive joins.

    - by IanC
    This is a SQL theory question. I can provide an example, but I don't think it's needed to make my point. Anyone experienced with SQL will immediately know what I'm talking about. Usually we use joins to minimize the number of records due to matching the left and right rows. However, under certain conditions, joining tables cause a multiplication of results where the result is all permutations of the left and right records. I have a database which has 3 or 4 such joins. This turns what would be a few records into a multitude. My concern is that the tables will be large in production, so the number of these joined rows will be immense. Further, heavy math is performed on each row, and the idea of performing math on duplicate rows is enough to make anyone shudder. I have two questions. The first is, is this something I should care about, or will SQL Server intelligently realize these rows are all duplicates and optimize all processing accordingly? The second is, is there any advantage to grouping each part of the query so as to get only the distinct values going into the next part of the query, using something like: WITH t1 AS ( SELECT DISTINCT... [or GROUP BY] ), t2 AS ( SELECT DISTINCT... ), t3 AS ( SELECT DISTINCT... ) SELECT... I have often seen the use of DISTINCT applied to subqueries. There is obviously a reason for doing this. However, I'm talking about something a little different and perhaps more subtle and tricky.

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  • What's the steps for SQL optimization and changes without reflect live system ?

    - by Space Cracker
    we have a big portal that build using SharePoint 2007 , asp.net 3.5 , SQL Server 2005 .. many developers work in it since 01/2008 and we are now doing huge analysis for current SQL Databases [not share-point DB ] to optimize and enhance it. The main db have about 330 table and 1720 stored procedure (SP) created from 01/2008 till now Many table names / Columns is very long and we want to short it we found SP names is written in 25 format :( , some of them are very complex and also we want to rename many SP parameters need to be renamed one of the biggest table is Registered user table, that will be spitted in more than one table for some optimization, many columns name will be changed I searched for the way that i can rename table names ,columns and i found SQL refactor tool but i still trying it .. my questions : Is SQl Refactor is the best tool for renaming ? or is there any other one ? if i want to make it manually, is there any references or best practice for that ? How can i do such changes in fast and stable way .. i search for recommendations and case studies if exist ?

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  • sortable list using jquery ui not passing updated list order

    - by Matthew Berman
    I am following the sortable lists railscast and got everything working except when I sort, the same (original) order gets passed to the update method each time, so it doesn't update the true order. Here's the code: In the view: %tbody#lineup{"data-update-url" => sort_lineups_url} - @lineup.pieces.each_with_index do |piece, index| = content_tag_for :tr, piece do = render 'piece', :piece => piece, :index => index and pieces.js.coffee: jQuery -> $('#lineup').sortable( axis: 'y' update: -> $.post($(this).data('update-url'), $(this).sortable('serialize')) ); sort and show methods of lineupscontroller: def show @lineup = Lineup.find_by_user_id(current_user.id) @pieces = @lineup.pieces.order("position") end def sort params[:piece].each_with_index do |id, index| current_user.lineup.pieces.update_all({position: index+1}, {id: id}) end render nothing: true end and the update request: Started POST "/lineups/sort" for 127.0.0.1 at 2012-06-24 20:06:14 -0700 Processing by LineupsController#sort as */* Parameters: {"piece"=>["8", "2", "1", "4", "3", "7"]} User Load (0.4ms) SELECT `users`.* FROM `users` WHERE `users`.`id` = 2 LIMIT 1 Lineup Load (0.6ms) SELECT `lineups`.* FROM `lineups` WHERE `lineups`.`user_id` = 2 LIMIT 1 SQL (2.9ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 1 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 8 SQL (0.6ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 2 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 2 SQL (0.6ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 3 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 1 SQL (0.5ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 4 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 4 SQL (0.6ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 5 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 3 SQL (0.5ms) UPDATE `pieces` INNER JOIN `piece_lineups` ON `pieces`.`id` = `piece_lineups`.`piece_id` SET `position` = 6 WHERE `piece_lineups`.`lineup_id` = 3 AND `pieces`.`id` = 7 Rendered text template (0.0ms) so each time i drag+drop the list, it sends the same order again. what am I doing wrong that the params isn't passing the right, updated order? Completed 200 OK in 2757ms (Views: 1.0ms | ActiveRecord: 6.7ms)

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  • Why doesn't Win Forms application update label immediately?

    - by rosscj2533
    I am doing some experimenting with threads, and made a 'control' method to compare against where all the processing happens in the UI thread. It should run a method, which will update a label at the end. This method runs four times, but the labels are not updated until all 4 have completed. I expected one label to get updated about every 2 seconds. Here's the code: private void button1_Click(object sender, EventArgs e) { Stopwatch watch = new Stopwatch(); watch.Start(); UIThreadMethod(lblOne); UIThreadMethod(lblTwo); UIThreadMethod(lblThree); UIThreadMethod(lblFour); watch.Stop(); lblTotal.Text = "Total Time (ms): " + watch.ElapsedMilliseconds.ToString(); } private void UIThreadMethod(Label label) { Stopwatch watch = new Stopwatch(); watch.Start(); for (int i = 0; i < 10; i++) { Thread.Sleep(200); } watch.Stop(); // this doesn't set text right away label.Text = "Done, Time taken (ms): " + watch.ElapsedMilliseconds; } Maybe I'm just missing something basic, but I'm stuck. Any ideas? Thanks.

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  • LINQ - 'Could not translate expression' with previously used and proven query condition

    - by tomfumb
    I am fairly new to LINQ and can't get my head around some inconsistency in behaviour. Any knowledgeable input would be much appreciated. I see similar issues on SO and elsewhere but they don't seem to help. I have a very simple setup - a company table and an addresses table. Each company can have 0 or more addresses, and if 0 one must be specified as the main address. I'm trying to handle the cases where there are 0 addresses, using an outer join and altering the select statement accordingly. Please note I'm currently binding the output straight to a GridView so I would like to keep all processing within the query. The following DOES work IQueryable query = from comp in context.Companies join addr in context.Addresses on comp.CompanyID equals addr.CompanyID into outer // outer join companies to addresses table to include companies with no address from addr in outer.DefaultIfEmpty() where (addr.IsMain == null ? true : addr.IsMain) == true // if a company has no address ensure it is not ruled out by the IsMain condition - default to true if null select new { comp.CompanyID, comp.Name, AddressID = (addr.AddressID == null ? -1 : addr.AddressID), // use -1 to represent a company that has no addresses MainAddress = String.Format("{0}, {1}, {2} {3} ({4})", addr.Address1, addr.City, addr.Region, addr.PostalCode, addr.Country) }; but this displays an empty address in the GridView as ", , ()" So I updated the MainAddress field to be MainAddress = (addr.AddressID == null ? "" : String.Format("{0}, {1}, {2} {3} ({4})", addr.Address1, addr.City, addr.Region, addr.PostalCode, addr.Country)) and now I'm getting the Could not translate expression error and a bunch of spewey auto-generated code in the error which means very little to me. The condition I added to MainAddress is no different to the working condition on AddressID, so can anybody tell me what's going on here? Any help greatly appreciated.

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  • Replacing XML in File from "Document" in Java

    - by poeschlorn
    Hi, after processing my first steps in working with XML in java I am now at the point where I want to update some data in my XML/GPX file... Reaplacing it in my "Document" data type works great :) How here comes the question: how can I store the changed "document"-model back to my file? Do I have to do this by using the standart file-functions (via steams and so on) oder is the a more elegant way to do this? ;-) Here's the code I already worked out, maybe that could help. (the method getParsedXML is just puting the conversion from the file into an extra method) Document tmpDoc = getParsedXML(currentGPX); //XML Parsind tests: // Access to tag attribute <tag attribut="bla"> System.out.println(tmpDoc.getElementsByTagName("wpt").item(0).getAttributes().getNamedItem("lat").getTextContent()); // Access to the value of an child element <a><CHILD>ValueOfChild</CHILD></a> System.out.println(tmpDoc.getElementsByTagName("wpt").item(0).getChildNodes().item(5).getTextContent()); // Replacing access to tag attribute tmpDoc.getElementsByTagName("wpt").item(0).getAttributes().getNamedItem("lat").setTextContent("139.921055008"); System.out.println(tmpDoc.getElementsByTagName("wpt").item(0).getAttributes().getNamedItem("lat").getTextContent()); // Replacing access to child element value tmpDoc.getElementsByTagName("wpt").item(0).getChildNodes().item(5).setTextContent("Cala Sant Vicenç - Mallorca 2"); System.out.println(tmpDoc.getElementsByTagName("wpt").item(0).getChildNodes().item(5).getTextContent());

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  • PHP include taking too long

    - by wxiiir
    I have a php file with around 100mb which is full of arrays (only arrays). I've made a script that includes this file (for processing), first it exhausted the default Xampp 128mb memory limit, i've raised it to 1024mb but it just takes forever and doesn't do anything. I'm sure the problem is being created by the sheer size of the file because i've tried removing all lines of code and just leaving the include and an echo for me to know when it finishes executing, and it does the same thing (which is taking forever), i've also tried to run the 100mb file in separate and same thing again. A 10mb file is taking forever as well but a similar 1mb file is almost instantly read and executed so the problem must be more than just the file size. I was avoiding using c++ for a simple project as this and would rather not to as php is easier for me and the task that will be executed doesn't need to benefit from the added speed that it would have if it had been done in c++ but if i have no luck in solving this problem i guess i'll have to. EDIT Reasons for not using a database: 1-Whoever made it didn't used a database and it will be pretty hard to store this in an organized database if i'm not able to do something with it first, like just reading it, copying parts from it or putting in memory or something. 2-I don't have experience working with databases as pretty much all stuff i've ever done in php didn't needed large amounts of stored data, 50kb at best, if i was thinking about a big project or huge chunks of data as this one, i definitely would, but i didn't made this mess to start with and now i have to undo it. 3-The logic for having to store a small portion of data like 10mb in hard drive when now every computer has pretty much enough ram to fit the whole OS in it is pretty much incomprehensible unless someone gives a good explanation about it, if i had to access a lot of said files simultaneously i would understand but like i said, this is a simple project, this is the only file that will be accessed at a given time this isn't even to make some kind of website, it's to run a few times and be done with it.

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  • git + partly shared files between branches/repositories. Is it possible?

    - by Maxym
    One team in company I work for has the following problem. They develop an application, which will have different builds (e.g. different design depending on customer). so they have some code shared between builds, and some specific to build. E.g. first build has (example is meaningless about files, it is just to understand the problem; I don't know exactly which code differs) /src/class1.java /src/class2.java /res/image1.png /res/image2.png second project contains /src/class1.java /src/class3.java /res/image1.png /res/image3.png as you see, both have class1.java and image1.png. Evething else is different. The project is much more complex of course, so to contain everything in one project is not comfortable... But also to make different branches and commit the same code to all of them is not comfortable... probably I picked wrong direction thinking about this problem, but I just took a look at git (we use svn), and it allows separated repositories. The question is: is it possible to make different branches in git, but tell it that "these files should be shared between them" and other files should be only in those branches. Then when developer commits class1.java git synchronizes it in all branches/repositorias etc. Maybe there is another solution which can be easy taken?

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  • C#: How to implement a smart cache

    - by Svish
    I have some places where implementing some sort of cache might be useful. For example in cases of doing resource lookups based on custom strings, finding names of properties using reflection, or to have only one PropertyChangedEventArgs per property name. A simple example of the last one: public static class Cache { private static Dictionary<string, PropertyChangedEventArgs> cache; static Cache() { cache = new Dictionary<string, PropertyChangedEventArgs>(); } public static PropertyChangedEventArgs GetPropertyChangedEventArgsa(string propertyName) { if (cache.ContainsKey(propertyName)) return cache[propertyName]; return cache[propertyName] = new PropertyChangedEventArgs(propertyName); } } But, will this work well? For example if we had a whole load of different propertyNames, that would mean we would end up with a huge cache sitting there never being garbage collected or anything. I'm imagining if what is cached are larger values and if the application is a long-running one, this might end up as kind of a problem... or what do you think? How should a good cache be implemented? Is this one good enough for most purposes? Any examples of some nice cache implementations that are not too hard to understand or way too complex to implement?

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  • Using unions to simplify casts

    - by Steven Lu
    I realize that what I am trying to do isn't safe. But I am just doing some testing and image processing so my focus here is on speed. Right now this code gives me the corresponding bytes for a 32-bit pixel value type. struct Pixel { unsigned char b,g,r,a; }; I wanted to check if I have a pixel that is under a certain value (e.g. r, g, b <= 0x10). I figured I wanted to just conditional-test the bit-and of the bits of the pixel with 0x00E0E0E0 (I could have wrong endianness here) to get the dark pixels. Rather than using this ugly mess (*((uint32_t*)&pixel)) to get the 32-bit unsigned int value, i figured there should be a way for me to set it up so I can just use pixel.i, while keeping the ability to reference the green byte using pixel.g. Can I do this? This won't work: struct Pixel { unsigned char b,g,r,a; }; union Pixel_u { Pixel p; uint32_t bits; }; I would need to edit my existing code to say pixel.p.g to get the green color byte. Same happens if I do this: union Pixel { unsigned char c[4]; uint32_t bits; }; This would work too but I still need to change everything to index into c, which is a bit ugly but I can make it work with a macro if i really needed to.

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  • Application HANGS UP if 3G connection is used (WiFi is OK)

    - by SkyEagle888
    Hi, My application uses the following codes to connect to web site and download a web page for processing. HttpURLConnection c = (HttpURLConnection) url.openConnection(); c.setRequestMethod("GET"); c.setRequestProperty("User-Agent", "Mozilla/3.0 (compatible; MSIE 4.0; Windows NT)"); c.setRequestProperty("Accept-Language", "zh-hk"); c.setRequestProperty("Connection", "Keep-Alive"); c.setConnectTimeout(6000); // mTimeout is in seconds intTries = 3; do { c.connect(); if (c.getResponseCode() == 200) { break; } else { intTries --; } } while (intTries > 0); The codes are run in main thread only. If WiFi is being used, it is nice and clean. If 3G connection is being used, sometimes, it cannot get connected OR application HANGS. Is there any significant difference between handling WiFi and 3G ? Thanks.

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  • Can anyone give me a sample java socket programming for doing a peer to peer for 3 systems?

    - by Sadesh Kumar N
    I am doing an university project. I need some sample programs on peer to peer programs in java socket programming. Every where people are telling to add a server socket in the client program. I am in a confusion. Can a single program having server socket and client socket will do or i have to create two programs of one initiating a system and another peer program running thrice to solve the problem. or i need to create three programs for three peer systems. I am not clear on the architecture of building peer to peer programs using java sockets. Can some one help me giving a simple program on how to create a peer to peer connection between three systems. I know how to do a socket program for client server model and clear on the concept. But creating a peer to peer architecture sounds complex for me to understand. I also referred this thread. developing peer to peer in java The person commented second says" To make peer2peer app each client opens server socket too. When client A wishes to connect to client B it just connects to its socket. " Need some more sample and an explanation on how peer to peer java socket program works I dont want any external api like jxta to do this task. I need a clear picture on how it works alone with an example.

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  • how do i call methods from another class in android?

    - by Phani Gargey
    I have two classes in question. Both extend Activity. Class A public void displayinfo() { setContentView(R.layout.dynamicinfo); //Add some buttons dynamically here //do some processing // move on to Class B } In Class B: I want to go back to Class A state in UI if BACK button is pressed. Class B //Register a listener for this button Backbutton.setOnClickListener(new OnClickListener() { public void onClick(View arg0) { Log.i("setOnClickListener", "Pressed Back Button "); Toast.makeText(mycontext, "Pressed Back Button", Toast.LENGTH_SHORT).show(); //HERE I want to go back class's function in UI as well as restoring the sttae for that screen. } how do I do that? I looked around some questions. they did not answer clearly what I am looking for.hence the posting. thanks.I think I was adding my own Back button on the Layout I created in the Class B's UI Screen --not using the regular "Back" button on the key board. May be that was the problem.

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  • SQL -- How is DISTINCT so fast without an index?

    - by Jonathan
    Hi, I have a database with a table called 'links' with 600 million rows in it in SQLite. There are 2 columns in the database - a "src" column and a "dest" column. At present there are no indices. There are a fair number of common values between src and dest, but also a fair number of duplicated rows. The first thing I'm trying to do is remove all the duplicate rows, and then perform some additional processing on the results, however I've been encountering some weird issues. Firstly, SELECT * FROM links WHERE src=434923 AND dest=5010182. Now this returns one result fairly quickly and then takes quite a long time to run as I assume it's performing a tablescan on the rest of the 600m rows. However, if I do SELECT DISTINCT * FROM links, then it immediately starts returning rows really quickly. The question is: how is this possible?? Surely for each row, the row must be compared against all of the other rows in the table, but this would require a tablescan of the remaining rows in the table which SHOULD takes ages! Any ideas why SELECT DISTINCT is so much quicker than a standard SELECT?

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  • NSMagedObjectContext, threads and NSFechedResultsController

    - by tmpz
    Dear iphone developers, Core Data newbie speaking here. In my application I have two NSManagedObjectContext that refer to that same NSPersistentStorageController. One ManagedObjectContext (c1) is in the main thread --created when I create a NSFetchedResultsController -- and the second ManagedObjectContext (c2) created in a second thread, running in the background, detached from the main thread. In the background thread I pull some data off a website and insert the entities created for the pulled data in the thread's ManagedObjectContext (c2). In the meanwhile, the main thread sits doing nothing and displaying a UITableView whose data do be display should be provided by the NSFetchedResultsController. When the background thread has finished pulling the data and inserting entities in c2, c2 saves, and the background thread notifies the main thread that the processing has finished before it exiting. As a matter of fact, the entities that I have inserted in c2 are know by c1 because it can ask it about one particular entity with [c1 existingObjectWithID:ObjectID error:&error]; I would expect at this point, if I call on my tableview reloadData to see some rows showing up with the data I pulled from the web in the background thread thanks to the NSFetchedResults controller which should react to the modifications of its ManagedObjectContext (c1). But nothing is happening! Only if I restart the application I see what I have previously pulled from the web! Where am I doing things wrong? Thank you in advance!

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  • Handling Email Bouncebacks in Rails

    - by aressidi
    Hi there, I've built a very basic CRM system for my rails app that allows me to send weekly user activity digests with custom text and create multi-part marketing messages which I can configure and send through a basic admin interface. I'm happy with what I've put together on the send-side of things (minus the fact that I haven't tried to volume test its capabilities), but I'm concerned about how to handle bounce-backs. I came across this plugin with associated scripts: http://github.com/kovyrin/bounces-handler I'm using Google Apps to handle my mail and really don't know enough about Perl to want to mess with the above plugin - I have enough headaches. I'm looking for a simple solution for processing bounce-backs in Rails. All my email will go out from an address like this which will be managed in Google Apps: "[email protected]." What's the best workflow for this? Can anyone post an example solution they're using keeping in mind the fact that I'm using Google Apps for the mail? Any guidance, links, or basic workflow best-practices to handle this would be greatly appreciated. Thanks! -A

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  • listview not updating,inserting

    - by raging_boner
    Data entered in textboxes is not getting updated in database. In debug mode I see that textbox1 and textbox2 in ItemUpdating event contain the same values as they had before calling ItemUpdating. Here's my listview control: <asp:ListView ID="ListView1" runat="server" onitemediting="ListView1_ItemEditing" onitemupdating="ListView1_ItemUpdating" oniteminserting="ListView1_ItemInserting"> //LayoutTemplate removed <ItemTemplate> <td align="center" valign="top"> <asp:Label ID="Label2" runat="server" Text='<%#Eval("id")%>'></asp:Label><br /> <asp:Label ID="Label3" runat="server" Text='<%#Eval("text1")%>'></asp:Label> </td> <td> <asp:LinkButton ID="LinkButton2" CommandName="Edit" runat="server">Edit</asp:LinkButton> <asp:LinkButton ID="LinkButton4" CommandName="Delete" runat="server">Delete</asp:LinkButton> </td> </ItemTemplate> <EditItemTemplate> <td align="center" valign="top"> <asp:Label ID="Label1" runat="server" Text='<%#Eval("id")%>'></asp:Label> <asp:TextBox ID="TextBox1" runat="server" Text='<%#Eval("text1")%>' TextMode="MultiLine" /> <asp:TextBox ID="TextBox2" runat="server" Text='<%#Eval("text2")%>' Height="100" TextMode="MultiLine" /> <asp:LinkButton ID="LinkButton1" CommandName="Update" CommandArgument='<%# Eval("id")%>' runat="server">Update</asp:LinkButton> <asp:LinkButton ID="LinkButton5" CommandName="Cancel" runat="server">Cancel</asp:LinkButton> </td> </EditItemTemplate> <InsertItemTemplate> <td align="center" valign="top"> <asp:TextBox ID="TextBox3" runat="server" TextMode="MultiLine" Height="100"></asp:TextBox> <asp:TextBox ID="TextBox4" runat="server" Height="100" TextMode="MultiLine"></asp:TextBox><br/> <asp:LinkButton ID="LinkButton3" runat="server">Insert</asp:LinkButton> </td> </InsertItemTemplate> </asp:ListView> Codebehind file: protected void ListView1_ItemEditing(object sender, ListViewEditEventArgs e) { ListView1.EditIndex = e.NewEditIndex; BindList(); } protected void ListView1_ItemUpdating(object sender, ListViewUpdateEventArgs e) { ListViewItem myItem = ListView1.Items[ListView1.EditIndex]; Label id = (Label)myItem.FindControl("Label1"); int dbid = int.Parse(id.Text); TextBox text1 = (TextBox)myItem.FindControl("Textbox1"); TextBox text2 = (TextBox)myItem.FindControl("Textbox2"); //tried to work withNewValues below, but they don't work, "null reference" error is being thrown //text1.Text = e.NewValues["text1"].ToString(); //text2.Text = e.NewValues["text2"].ToString(); //odbc connection routine removed. //i know that there should be odbc parameteres: comm = new OdbcCommand("UPDATE table SET text1 = '" + text1.Text + "', text2 = '" + text2.Text + "' WHERE id = '" + dbid + "'", connection); comm.ExecuteNonQuery(); conn.Close(); ListView1.EditIndex = -1; //here I databind ListView1 } What's wrong with updating of text1.Text, text2.Text in ItemUpdating event? Should I use e.NewValues property? If so, how to use it? Thanks in advance for any help.

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