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  • Integrating Amazon EC2 in Java via NetBeans IDE

    - by Geertjan
    Next, having looked at Amazon Associates services and Amazon S3, let's take a look at Amazon EC2, the elastic compute cloud which provides remote computing services. I started by launching an instance of Ubuntu Server 14.04 on Amazon EC2, which looks a bit like this in the on-line AWS Management Console, though I whitened out most of the details: Now that I have at least one running instance available on Amazon EC2, it makes sense to use the services that are integrated into NetBeans IDE:  I created a new application with one class, named "AmazonEC2Demo". Then I dragged the "describeInstances" service that you see above, with the mouse, into the class. Then the IDE automatically created all the other files you see below, i.e., 4 Java classes and one properties file: In the properties file, register the access ID and secret keys. These are read by the other generated Java classes. Signing and authentication are done automatically by the code that is generated, i.e., there's nothing generic you need to do and you can immediately begin working on your domain-specific code. Finally, you're now able to rewrite the code in "AmazonEC2Demo" to connect to Amazon EC2 and obtain information about your running instance: public class AmazonEC2Demo { public static void main(String[] args) { String instanceId1 = "i-something"; RestResponse result; try { result = AmazonEC2Service.describeInstances(instanceId1); System.out.println(result.getDataAsString()); } catch (IOException ex) { Logger.getLogger(AmazonEC2Demo.class.getName()).log(Level.SEVERE, null, ex); } } } From the above, you'll receive a chunk of XML with data about the running instance, it's name, status, dates, etc. In other words, you're now ready to integrate Amazon EC2 features directly into the applications you're writing, without very much work to get started. Within about 5 minutes, you're working on your business logic, rather than on the generic code that anyone needs when integrating with Amazon EC2.

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  • F# Objects &ndash; Part 3 &ndash; it&rsquo;s time to overload&hellip;

    - by MarkPearl
    Okay, some basic examples of overloading in F# Overloading Constructors Assume you have a F# object called person… type Person (firstname : string, lastname : string) = member v.Fullname = firstname + " " + lastname   This only has one constructor. To add additional constructors to the object by explicitly declaring them using the method member new. type Person (firstname : string, lastname : string) = new () = Person("Unknown", "Unknown") member v.Fullname = firstname + " " + lastname   In the code above I added another constructor to the Person object that takes no parameters and then refers to the primary constructor. Using the same technique in the code below I have created another constructor that accepts only the firstname as a parameter to create an object. type Person (firstname : string, lastname : string) = new () = Person("Unknown", "Unknown") new (firstname : string) = Person(firstname, "Unknown") member v.Fullname = firstname + " " + lastname   Overloading Operators So, you can overload operators of objects in F# as well… let’s look at example code… type Person(name : string) = member v.name = name static member (+) (person1 : Person , person2 : Person) = Person(person1.name + " " + person2.name)   In the code above we have overloaded the “+” operator. Whenever we add to Person objects together, it will now create a new object with the combined names…

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  • Why OpenDialog.py don't work on Jotty application

    - by venerable13
    I'm a Python beginner, I installed quickly, I wrote a "quickly tutorial" in terminal and I did all the steps before at: "However, the application is not complete. There are a few things left for you to do:" All the next steps aren't finished yet because when I use open dialog and select one of the files saved, the content of the file isn't showed on "textview1", Why? Only is deleted the content written. Before if was used without dialog works great. SaveDialog.py work great. -def on_mnu_new_activate(self, widget, data=None) don't work neither. -If I use the bold lines by the others don't work. ###def open_file(self, widget, data=None): def on_mnu_open_activate(self, widget, data=None): ###def save_file(self, widget, data=None): def on_mnu_save_activate(self, widget, data=None): To view the code, go to the link above, unrar the archive, install "quickly" if you don't have it yet, place inside on jotty directory, then put "quickly run", "quickly edit", "quickly design", depending what do you want to do. Code - problematic code with OpenDialog implemented. Code-part1 - works OK, but without OpenDialog. I need principally that OpenDialog function work great.

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  • Setting up a LAMP VM server for Development and Testing?

    - by TdotThomas
    Info: I would like to set up a VM server on my local computer which will serve pages in the exact same way as my current hosting (but only to me on my local computer). I currently pay a big web hosting company to host my website & web store and they are doing a great job, but I would like to be able to work on my Web site and its corresponding MySQL DB, HTML, and PHP code without being at risk of messing something completely up on the live servers. My current plan of action: Set up a VM webserver with Debian, MySQL, PHP, Apache. Copy web store (PHP/HTML) code to VM server. Copy my current MySQL databases from my hosting provider and install on VM server. Modify and test new features on VM server. Upload MySQL DB and HTML/PHP code back to web host's server where it should work as before but with new modifications. Questions: Now I'm pretty sure I have steps one and two down correctly but I can't for the life of me figure out how to proceed next, so here are my questions. I have my /etc/host file set up so www.MySite.test redirects to the IP address of the local VM webserver. Once I import my PHP/HTML files and MySQL file whats the best way to navigate around the fact that all of my files and DBs will reference www.MySite.com. I can export my MySQL dbs but do I also have to export my MySQL users and passwords to access those db or are those coded into my html/php code?

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  • How can I fix the #c3284d# malvertising hack on my website?

    - by crm
    For the past couple of weeks at semi regular intervals, this website has had the #c3284d# malware code inserted into some of its .php files. Also the .htaccess file had its equivelant code inserted. I have, on many occasions removed the malicious code, replaced files, changed the ftp password on my ftp client (which is CoreFTP), changed the connection method to FTPS for more secure storage of the password (instead of plain text). I have also scanned my computer several times using AVG and Windows Defender which have found no malware on my computer which might have been storing my ftp passwords. I used Sucuri SiteCheck to check my website which says my website is clean of malware which is bizarre because I just attempted to click one of the links on the site a minute ago and it linked me to another one of these random stats.php sites, even though it appears I have gotten rid of the #c3284d# code again (which will no doubt be re-inserted somehow in an hour or so).. Has anyone found an actual viable solution for this malware hack? I have done just about all of the things suggested here and here and the problem still persists. Currently when I click on a link within the sites navigation menu within Google Chrome I get googles Malware warning page: Warning: Something's Not Right Here! oxsanasiberians.com contains malware. Your computer might catch a virus if you visit this site. Google has found that malicious software may be installed onto your computer if you proceed. If you've visited this site in the past or you trust this site, it's possible that it has just recently been compromised by a hacker. You should not proceed. Why not try again tomorrow or go somewhere else? We have already notified oxsanasiberians.com that we found malware on the site. For more about the problems found on oxsanasiberians.com, visit the Google Safe Browsing diagnostic page. I'm wondering if it is possible that the Google Chrome browser I am using has itself been hacked? Does anyone else get re-directed when clicking links on the the website?

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  • Installing a new ASP.NET 4.0 site on a Windows 2008 server.

    - by TATWORTH
    I have been specifically requested to blog about getting an ASP.NET 4.0 site working on a Windows 2008 server that has never run a 4.0 web site before. Make sure the 4.0 framework is installed on the server! Patch it will ALL the security patches have been applied. ((for a live server, make sure that you tested the patches on your development server first) You will find the HTTP Log status codes at http://support.microsoft.com/kb/943891 - they are very important in understandign the IIS logs) After installing, turn on 4.0, by doing the following: Start the Internet Information Services (IIS Manager) Select the server node in the connections pane. (this is the node above Application Pools, FTP Sites and Server Farms) Double click the ISAPI and CGI Restrictions item in the centre pane You should see 1 or 2 ASP.NET v4.0.30319 entries, select Enable in the Actions pane for all of them. ASP.NET 4.0 should now run! Remeber after creating your new 4.0 ASP.NET site. select the Sites node and find out the Id of it. By default, the IIS logs are at C:\inetpub\logs\LogFiles and if your site is say 21, then the logs will be created in the W3SVC21 sub-directory. The key point about using these logs is that in the event of an error when trying to start the site for the first time, the log will contain the status code and the sub-code. By having the full code and sub-code, set up issues can be resolved in minutes instead of hours.

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  • What's wrong performing unit test against concrete implementation if your frameworks are not going to change?

    - by palm snow
    First a bit of background: We are re-architecting our product suite that was written 10 years ago and served its purpose. One thing that we cannot change is the database schema as we have 500+ client base using this system. Our db schema has over 150+ tables. We have decided on using Entity Framework 4.1 as DAL and still evaluating various frameworks for storing our business logic. I am investigation to bring unit testing into the mix but I also confused as to how far I need to go with setting up a full blown TDD environment. One aspect of setting up unit testing is by getting into implementing Repository, unit of work and mocking frameworks etc. This mean there will be cost and investment on the code-bloat associated with all these frameworks. I understand some of this could be auto-generated but when it comes to things like behaviors, that will be mostly hand written. Just to be clear, I am not questioning the important of unit testing your code. I am just not sure we need all its components (like repository, mocking etc.) when we are fairly certain of storage mechanism/framework (SQL Server/Entity Framework). All that code bloat with generic repositories make sense when you need a generic layers with ability to change this whenever you like however its very likely a YAGNI in our case. What we need is more of integration testing where we can unit-test our code with concrete repository objects and test data in database. In this scenario, just running integration test seem to be more beneficial in our case. Any thoughts if I am missing any thing here?

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  • Using the RadTransitionControl in Task-It

    Download Source Code NOTE: To run the source code provided your will need to update to the RC (release candidate) versions of Silverlight 4 and VisualStudio 2010.  In a recent Ask the Experts webinar I showed a simple solution that had similarities to one that I had used in my recent MVVM post, but had a few extra twists on it. I have since been asked if I could post the source code for this demo, so here it is (I am using similar techniques in my Task-It application). The database Before running the code for this app you will need to create the database. First, create a database called MVVMProject in SQL Server, then run MVVMProject.sql in the MVVMProjectDemo/Database directory of your downloaded .zip file. This should give you a Task table with 3 records in it. You will also need to update the connection string in web.config to point to your database ...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Standard/Compliance for web programming?

    - by MarkusK
    I am working with developers right now that write code the way they want and when i tell them to do it other way they respond that its just matter of preference how to do it and they have their way and i have mine. I am not talking about the formatting of code, but rather of way site is organized in classes and the way the utilize them. and the way they create functions and process forms etc. Their coding does not match my standards, but again they argue that its matter of preference and as long as goal achieved the can be different way's to do it. I agree but their way is proven to have bugs and we spend a lot of time going back and forth with them to fix all problems security or functionality, yet they still write same code no matter how many times i asked them to stop doing certain things. Now i am ready to dismiss them but friend of mine told me that he has same exact problem with freelance developers he work with. So i don't want to trade one bad apple for another. Question is is there some world wide (or at least europe and usa) accepted standard or compliance on how write secure web based applications. What application architecture should be for maintainable application. Is there are some general standard that can be used for any language ruby php or java govern security and functionality and quality of code? Or at least for PHP and MySQL i use for my website. So i can make them follow this strict standard and stop making excuses.

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  • what will EcmaScript 6 bring to the table for us

    - by user697296
    Our company ported moderate chunks of business logic to JavaScript. We compile the code with a minifier, which further improves performance. Since the language is dynamically typed, it lends itself well to obfuscation, which occurs as a byproduct of minification. We went to great efforts to ensure it positively screams, performance-wise. We can now do what we did before, faster, better, with less code, on more platforms. In summary, we are very satisfied with the current state of the language. I personally love the language especially for its cross-platform nature. So naturally, I read up a lot about the state of JavaScript compilers, performance and compatibility across as many browsers and platforms as I have time to research. The one theme which has been growing louder and louder these days, is the news about ECMAScript 6. So far, what I have been able to gather is that ES6 promises a better development experience; firstly by enabling new ways to do things, secondly by reporting errors early. This sounds great for those who are still waiting for the language to meet their needs before jumping on board. But we have already jumped on board in a big way. Sure, I expect that we will have to do ongoing maintenance and feature revisions on our code through the years, and that we would obviously make use of best practices at the time. But I don't see us refactoring major portions of it to take advantage of language features that are mostly intended to boost developer productivity. I keep wondering, what impact will the language advances ultimately have on our existing, well-written, well-performing code base? Is there something I am missing? Is there something we ought to look out for? Does anyone have tips or guidance on how we should approach the ecmascript.next finalization? Should we care?

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  • In developing a soap client proxy, which return structure is easier to use and more sensible?

    - by cori
    I'm writing (in PHP) a client/proxy for a SOAP web service. The return types are consistently wrapped in response objects that contain the return values. In many cases this make a lot of sense - for instance when multiple values are being returned: GetDetailsResponse Object ( Results Object ( [TotalResults] => 10 [NextPage] => 2 ) [Details] => Array ( [0] => Detail Object ( [Id] => 1 ) ) ) But some of the methods return a single scalar value or a single object or array wrapped in a response object: GetThingummyIdResponse Object ( [ThingummyId] => 42 ) In some cases these objects might be pretty deep, so getting at properties within requires drilling down several layers: $response->Details->Detail[0]->Contents->Item[5]->Id And if I unwrap them before passing them back I can strip out a layer from consumers' code. I know I'm probably being a little bit of an Architecture Astronaut here, but the latter style really bug me, so I've been working through my code to have my proxy methods just return the scalar value to the client code where there's no absolute need for a wrapper object. My question is, am I actually making things more difficult for the consumers of my code? Would I be better off just leaving the return values wrapped in response objects so that everything is consistent, or is removing unneccessary layers of indirection/abstraction worthwhile?

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  • Using the Coherence ConcurrentMap Interface (Locking API)

    - by jpurdy
    For many developers using Coherence, the first place they look for concurrency control is the com.tangosol.util.ConcurrentMap interface (part of the NamedCache interface). The ConcurrentMap interface includes methods for explicitly locking data. Despite the obvious appeal of a lock-based API, these methods should generally be avoided for a variety of reasons: They are very "chatty" in that they can't be bundled with other operations (such as get and put) and there are no collection-based versions of them. Locks do directly not impact mutating calls (including puts and entry processors), so all code must make explicit lock requests before modifying (or in some cases reading) cache entries. They require coordination of all code that may mutate the objects, including the need to lock at the same level of granularity (there is no built-in lock hierarchy and thus no concept of lock escalation). Even if all code is properly coordinated (or there's only one piece of code), failure during updates that may leave a collection of changes to a set of objects in a partially committed state. There is no concept of a read-only lock. In general, use of locking is highly discouraged for most applications. Instead, the use of entry processors provides a far more efficient approach, at the cost of some additional complexity.

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  • SDL blitting multiple surfaces at once

    - by extropic_engine
    I'm trying to write a platforming game where the sprites for the level backgrounds are broken up into 512x512 chunks. I keep 3 chunks in memory at a time and I'm trying to write code to blit all three to the screen. Here is the current code I have: SDL_Rect where; where.y = -game->camera->y; where.x = -game->camera->x - MAP_WIDTH; SDL_BlitSurface(left_chunk, NULL, screen, &where); where.x = -game->camera->x; SDL_BlitSurface(center_chunk, NULL, screen, &where); where.x = -game->camera->x + MAP_WIDTH; SDL_BlitSurface(right_chunk, NULL, screen, &where); The issue I'm running into is that whichever chunk gets blitted first is the only one that shows up. The rest fail to appear onscreen. I think the issue might have something to do with alpha transparency, but even if the chunks don't overlap at all they still fail to blit. In other parts of the code I'm blitting multiple things to the screen at once, such as characters and backgrounds, and they all show up correctly. This particular segment of code is the only area I'm encountering this problem. If I comment out the line that blits left_chunk, it changes to this:

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  • How to use Twitter4j With JSF2 for Login? [on hold]

    - by subodh
    I am trying to do login with Twitter and using Twitter4j for that and wrote this code In JSF <h:commandButton id="twitterbutton" value="Sign up with Twitter" action="#{twitterLoginBean.redirectTwitterLogin}" immediate="true" styleClass="twitterbutton"/> In ManagedBean public String redirectTwitterLogin() throws ServletException, IOException, TwitterException { HttpServletRequest request = (HttpServletRequest) FacesContext .getCurrentInstance().getExternalContext().getRequest(); HttpServletResponse response = (HttpServletResponse) FacesContext .getCurrentInstance().getExternalContext().getResponse(); Twitter twitter = TwitterFactory.getSingleton(); twitter.setOAuthConsumer(apiKey, apiSecret); RequestToken requestToken = twitter.getOAuthRequestToken(); if (requestToken != null) { AccessToken accessToken = null; BufferedReader br = new BufferedReader(new InputStreamReader( System.in)); while (null == accessToken) { try { String pin = br.readLine(); accessToken = twitter .getOAuthAccessToken(requestToken, pin); } catch (TwitterException te) { System.out .println("Failed to get access token, caused by: " + te.getMessage()); System.out.println("Retry input PIN"); } } request.setAttribute(IS_AUTHENTICATED, true); if (accessToken != null) { LOGGER.debug("We have a valid oauth token! Make the facebook request"); doApiCall(twitter, request, response); return null; } } else { LOGGER.debug("We don't have auth code yet, fetching the Authorization URL..."); String authorizationUrl = requestToken.getAuthorizationURL(); LOGGER.debug("Redirecting to the Authorization URL: {}", authorizationUrl); request.setAttribute(IS_AUTHENTICATED, false); redirect(authorizationUrl, response); return null; } return null; } In above code i want first Login window of twitter will show and then again same method will call and after user will login i can show user information userId,Handel,location etc. Redirect private void redirect(String url, HttpServletResponse response) throws IOException { String urlWithSessionID = response.encodeRedirectURL(url); response.sendRedirect(urlWithSessionID); } But this code is not working Can anyone tell better Solution for this ?

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  • Problem with understanding how to start

    - by Coolface
    Okay, this might be a little off-topic but i try anyway. Sorry to bother. So i'm working as sysadmin for at least 5 years now and i quite enjoy IT field in general. Somehow i was never interested in programming much but always want to learn something at least easy and for personal usage. As sysadmin i need scripting skills so learn shell scripting without much problems, i also try to learn pascal, delphi, basic over time and must recent was python. Well, my problem is when i try to learn programming i just can't apply what i learn from the books to the real word. What i mean is i understand there are data structures, algorithms, variables, lib's, if-then logic, etc. but i just can't understand how to apply this things when i want to do real things. Like i want to get a something simple as parse web page, i draw a quick algorithm like get a web page, find a word on it and write a to file, on the paper everything look simple but when i get to the coding i just stuck pretty much from the start. I try read code of the real programs that just totally confusing especially big parts with many classes so i'm just quickly lost a trail what this code do. I think i just lack some fundamentals to see a big picture but don't really know what this might be? Or maybe i just don't have a passion to programming at all... My best bet was a shell scripting so i have really no problems to write complex scripts but this just not enough. Recently i was read around 5 or 6 python books because everyone say it's so easy even kid can code something but still no much luck, python is good and easy but i can't make something harder then a prodecurial style code like in bash for easy things but when i want harder things i'm still stuck. In college i was also not a math and tech guy and like to study non-tech stuff mostly like economy, psychology maybe that my problem? Anyway any advice would be greatly appriciated.

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  • jquery is not working over local network [migrated]

    - by Kortyell Davis
    i have a fedora server running apache web server. the server is connected to a home network. i have a laptop connected to the same network. i can enter the ip address of my server into the browser of my laptop and pull up the index.html file located in the document root directory of the fedora home server. the index.html file contains jquery code. the jquery code only works when i open it locally in my browser (e.g. right click open with firefox), but when i attempt to view the webpage from my laptop the jquery code is not executed. the code is here below. <script type="text/javascript" src="jquery-1.8.2.js"></script> ' $(document).ready(function() { $('#form').hide(); $('input[type=text]').focus(function() { $(this).val(''); }); $('input[type=password]').focus(function() { $(this).val(''); }); $('.form').hide(); $('#log').click(function(){ $('#form').toggle(); }); $('#reg').click(function(){ $('.form').toggle(); }); });

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  • ?????????????????:???????Oracle Solaris Studio 12.3?

    - by kazun
    2011?12?16??????????????????????? Oracle Solaris Studio 12.3 ??????????? Oracle Solaris Studio 12.3 ??C?C++?Fortran?????????????????????????????·??????????SPARC T4?x86??????????????????????????????300%??????????????????Studio 12.3 ?Oracle Solaris?Oracle Linux?Red Hat Enterprise Linux ???????????????????????? ??????Oracle Solaris Studio 12.3???????????????????? Oracle Solaris Studio 12.3 ?3?????? - ?????????????????????????? - ??????? - ??????·??????????????? Oracle Solaris Studio 12.3 ??? ???????????????? SPARC-T4???????????GCC???????300%, x86??????150%????????????????Sun Studio 12??????SPARC-T4?40%?x86?20%??????????????? ???????????????? ?????????????????????????????????Code Analyzer??????????????????????????????????????????Performance Analyzer???????????????????????????????????? ???????? Oracle Solaris?Oracle Linux??OS??????????????????????????·???????????????????????????????????????????????????20%???????????????????????????????·??????(SSH??)???????????Oracle Solaris?Linux?Windows?Mac OS?????????Oracle Solaris?Linux??????????????????????????????????????????·??????????????????Oracle Database????????????????????Pro*C ??????Oracle Solaris Studio?????????? Oracle Solaris Studio 12.3 ??? ?:Oracle Solaris Studio ??? Compiler Suite C/C++?Fortran ??????????????????????????(?????????????????)?????????????????·???????????????????????????????????????????? Analysis Suite ?Performance Analyzer??Code Analyzer??Thread Analyzer??3???????????????Code Analyzer?????????????????·???????????????????????????Performance Analyzer??????????????????????????????·??????????????????????????????????????Thread Analyzer????????????????????????????Solaris ?????P-?????OpenMP3.1???????????????????????????????????????????????????????????????????????????????????? ?:Code Analyzer ?????IDE?? ?Oracle Solaris Studio????????????(IDE)???????NetBeans???????????????????Oracle DB?MySQL???????Pro*C?OCI????????????????????????????·??????????????????????????????????????????????????????????????????????????????? Oracle Solaris Studio 12.3???? ???????????????Solaris Studio 12.3???????????????????????·?????????????????·??????????????????????????????? ??????????? ?Oracle Solaris Studio 12.3???????????????? ?????? Solaris Studio 12.3 ????????? ?????? ??????????????????????????????????????Solaris Studio ??????????????????????????????????????Oracle Solaris Studio ??????????????????? Oracle Solaris Studio Oracle Solaris

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  • Implements EAN13 and UPC-A barcode in PDF using fpdf in classic ASP

    - by Jeremy N
    /* FPDF library for ASP can be downloaded from: http://www.aspxnet.it/public/default.asp INFORMATIONS: Translated by: Jeremy Author: Olivier License: Freeware DESCRIPTION: This script implements EAN13 and UPC-A barcodes (the second being a particular case of the first one). Bars are drawn directly in the PDF (no image is generated) function EAN13(x,y,barcode,h,w) -x = x coordinate to start drawing the barcode -y = y coordinate to start drawing the barcode -barcode = code to write (must be all numeric) -h = height of the bar -w = the minimum width of individual bar function UPC_A(x,y,barcode,h,w) Same parameters An EAN13 barcode is made up of 13 digits, UPC-A of 12 (leading zeroes are added if necessary). The last digit is a check digit; if it's not supplied or if it is incorrect, it will be automatically computed. USAGE: Copy all of this text and save it in a file called barcode.ext file under fpdf/extends folder EXAMPLE: Set pdf=CreateJsObject("FPDF") pdf.CreatePDF "P","mm","letter" pdf.SetPath("fpdf/") pdf.LoadExtension("barcode") pdf.Open() pdf.AddPage() 'set the fill color to black pdf.setfillcolor 0,0,0 pdf.UPC_A 80,40,"123456789012",16,0.35 pdf.Close() pdf.NewOutput "" , true, "test.pdf" */ this.EAN13=function (x,y,barcode,h,w) { return this.Barcode(x,y,barcode,h,w,13); }; this.UPC_A=function (x,y,barcode,h,w) { return this.Barcode(x,y,barcode,h,w,12); }; function GetCheckDigit(barCode) { bc = barCode.replace(/[^0-9]+/g,''); total = 0; //Get Odd Numbers for (i=bc.length-1; i=0; i=i-2) { total = total + parseInt(bc.substr(i,1)); } //Get Even Numbers for (i=bc.length-2; i=0; i=i-2) { temp = parseInt(bc.substr(i,1)) * 2; if (temp 9) { tens = Math.floor(temp/10); ones = temp - (tens*10); temp = tens + ones; } total = total + temp; } //Determine the checksum modDigit = (10 - total % 10) % 10; return modDigit.toString(); } //Test validity of check digit function TestCheckDigit(barcode) { var cd=GetCheckDigit(barcode.substring(0,barcode.length-1)); return cd==parseInt(barcode.substring(barcode.length-1,1)); } this.Barcode=function Barcode(x,y,barcode,h,w,len) { //Padding while(barcode.length < len-1) { barcode = '0' + barcode; } if(len==12) {barcode='0' + barcode;} //Add or control the check digit if(barcode.length==12) { barcode += GetCheckDigit(barcode); } else { //if the check digit is incorrect, fix the check digit. if(!TestCheckDigit(barcode)) { barcode = barcode.substring(0,barcode.length-1) + GetCheckDigit(barcode.substring(0,barcode.length-1)); } } //Convert digits to bars var codes=[['0001101','0011001','0010011','0111101','0100011','0110001','0101111','0111011','0110111','0001011'], ['0100111','0110011','0011011','0100001','0011101','0111001','0000101','0010001','0001001','0010111'], ['1110010','1100110','1101100','1000010','1011100','1001110','1010000','1000100','1001000','1110100'] ]; var parities=[[0,0,0,0,0,0], [0,0,1,0,1,1], [0,0,1,1,0,1], [0,0,1,1,1,0], [0,1,0,0,1,1], [0,1,1,0,0,1], [0,1,1,1,0,0], [0,1,0,1,0,1], [0,1,0,1,1,0], [0,1,1,0,1,0] ]; var code='101'; var p=parities[parseInt(barcode.substr(0,1))]; var i; for(i=1;i<=6;i++) { code+= codes[p[i-1]][parseInt(barcode.substr(i,1))]; } code+='01010'; for(i=7;i<=12;i++) { code+= codes[2][parseInt(barcode.substr(i,1))]; } code+='101'; //Draw bars for(i=0;i<code.length;i++) { if(code.substr(i,1)=='1') { this.Rect(x+i*w,y,w,h,'F'); } } //Print text uder barcode. this.SetFont('Arial','',12); //Set the x so that the font is centered under the barcode this.Text(x+parseInt(0.5*barcode.length)*w,y+h+11/this.k,barcode.substr(barcode.length-len,len)); }

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  • Android: get current location from best available provider

    - by AP257
    Hi all, I have some Android code that needs to get the best available location QUICKLY, from GPS, network or whatever is available. Accuracy is less important than speed. Getting the best available location is surely a really standard task. Yet I can't find any code to demonstrate it. The Android location code expects you to specify criteria, register for updates, and wait - which is fine if you have detailed criteria and don't mind waiting around. But my app needs to work a bit more like the Maps app does when it first locates you - work from any available provider, and just check the location isn't wildly out of date or null. I've attempted to roll my own code to do this, but am having problems. (It's inside an IntentService where an upload happens, if that makes any difference. I've included all the code for info.) What's wrong with this code? @Override protected void onHandleIntent(Intent arg0) { testProviders(); doUpload(); } private boolean doUpload() { int j = 0; // check if we have accurate location data yet - wait up to 30 seconds while (j < 30) { if ((latString == "") || (lonString == "")) { Log.d(LOG_TAG, "latlng null"); Thread.sleep(1000); j++; } else { Log.d(LOG_TAG, "found lat " + latString + " and lon " + lonString); break; } //do the upload here anyway, with or without location data //[code removed for brevity] } public boolean testProviders() { Log.e(LOG_TAG, "testProviders"); String location_context = Context.LOCATION_SERVICE; locationmanager = (LocationManager) getSystemService(location_context); List<String> providers = locationmanager.getProviders(true); for (String provider : providers) { Log.e(LOG_TAG, "registering provider " + provider); listener = new LocationListener() { public void onLocationChanged(Location location) { // keep checking the location - until we have // what we need //if (!checkLoc(location)) { Log.e(LOG_TAG, "onLocationChanged"); locationDetermined = checkLoc(location); //} } public void onProviderDisabled(String provider) { } public void onProviderEnabled(String provider) { } public void onStatusChanged(String provider, int status, Bundle extras) { } }; locationmanager.requestLocationUpdates(provider, 0, 0, listener); } Log.e(LOG_TAG, "getting updates"); return true; } private boolean checkLoc(Location location) { float tempAccuracy = location.getAccuracy(); int locAccuracy = (int) tempAccuracy; Log.d(LOG_TAG, "locAccuracy = " + locAccuracy); if ((locAccuracy != 0) && (locAccuracy < LOCATION_ACCURACY)) { latitude = location.getLatitude(); longitude = location.getLongitude(); latString = latitude.toString(); lonString = longitude.toString(); return true; } return false; } public void removeListeners() { // Log.e(LOG_TAG, "removeListeners"); if ((locationmanager != null) && (listener != null)) { locationmanager.removeUpdates(listener); } locationmanager = null; // Log.d(LOG_TAG, "Removed " + listener.toString()); } @Override public void onDestroy() { super.onDestroy(); removeListeners(); } Unfortunately, this finds the network provider, but only ever outputs latlng null 30 times - it never seems to get a location at all. I never even get a log statement of locationChanged. It's funny, because from ddms I can see output like: NetworkLocationProvider: onCellLocationChanged [305,8580] NetworkLocationProvider: getNetworkLocation(): returning cache location with accuracy 75.0 seeming to suggest that the network provider does have some location info after all, I'm just not getting at it. Can anyone help? I think working example code would be a useful resource for the Android/StackOverflow community.

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  • CUDA not working in 64 bit windows 7

    - by Programmer
    I have cuda toolkit 4.0 installed in a 64 bit windows 7. I try building my cuda code, #include<iostream> #include"cuda_runtime.h" #include"cuda.h" __global__ void kernel(){ } int main(){ kernel<<<1,1>>>(); int c = 0; cudaGetDeviceCount(&c); cudaDeviceProp prop; cudaGetDeviceProperties(&prop, 0); std::cout<<"the name is"<<prop.name; std::cout<<"Hello World!"<<c<<std::endl; system("pause"); return 0; } but operation fails. Below is the build log: Build Log Rebuild started: Project: god, Configuration: Debug|Win32 Command Lines Creating temporary file "c:\Users\t-sudhk\Documents\Visual Studio 2008\Projects\god\god\Debug\BAT0000482007500.bat" with contents [ @echo off echo "C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v4.0\bin\nvcc.exe" -gencode=arch=compute_10,code=\"sm_10,compute_10\" -gencode=arch=compute_20,code=\"sm_20,compute_20\" --machine 32 -ccbin "C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\bin" -Xcompiler "/EHsc /W3 /nologo /O2 /Zi /MT " -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v4.0\include" -maxrregcount=0 --compile -o "Debug/sample.cu.obj" sample.cu "C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v4.0\bin\nvcc.exe" -gencode=arch=compute_10,code=\"sm_10,compute_10\" -gencode=arch=compute_20,code=\"sm_20,compute_20\" --machine 32 -ccbin "C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\bin" -Xcompiler "/EHsc /W3 /nologo /O2 /Zi /MT " -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v4.0\include" -maxrregcount=0 --compile -o "Debug/sample.cu.obj" "c:\Users\t-sudhk\Documents\Visual Studio 2008\Projects\god\god\sample.cu" if errorlevel 1 goto VCReportError goto VCEnd :VCReportError echo Project : error PRJ0019: A tool returned an error code from "Compiling with CUDA Build Rule..." exit 1 :VCEnd ] Creating command line """c:\Users\t-sudhk\Documents\Visual Studio 2008\Projects\god\god\Debug\BAT0000482007500.bat""" Creating temporary file "c:\Users\t-sudhk\Documents\Visual Studio 2008\Projects\god\god\Debug\RSP0000492007500.rsp" with contents [ /OUT:"C:\Users\t-sudhk\Documents\Visual Studio 2008\Projects\god\Debug\god.exe" /LIBPATH:"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v4.0\lib\x64" /MANIFEST /MANIFESTFILE:"Debug\god.exe.intermediate.manifest" /MANIFESTUAC:"level='asInvoker' uiAccess='false'" /DEBUG /PDB:"C:\Users\t-sudhk\Documents\Visual Studio 2008\Projects\god\Debug\god.pdb" /DYNAMICBASE /NXCOMPAT /MACHINE:X86 cudart.lib cuda.lib kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib ".\Debug\sample.cu.obj" ] Creating command line "link.exe @"c:\Users\t-sudhk\Documents\Visual Studio 2008\Projects\god\god\Debug\RSP0000492007500.rsp" /NOLOGO /ERRORREPORT:PROMPT" Output Window Compiling with CUDA Build Rule... "C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v4.0\bin\nvcc.exe" -gencode=arch=compute_10,code=\"sm_10,compute_10\" -gencode=arch=compute_20,code=\"sm_20,compute_20\" --machine 32 -ccbin "C:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\bin" -Xcompiler "/EHsc /W3 /nologo /O2 /Zi /MT " -I"C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v4.0\include" -maxrregcount=0 --compile -o "Debug/sample.cu.obj" sample.cu sample.cu sample.cu.obj : error LNK2019: unresolved external symbol _cudaLaunch@4 referenced in function "enum cudaError cdecl cudaLaunch(char *)" (??$cudaLaunch@D@@YA?AW4cudaError@@PAD@Z) sample.cu.obj : error LNK2019: unresolved external symbol ___cudaRegisterFunction@40 referenced in function "void __cdecl _sti_cudaRegisterAll_52_tmpxft_00001c68_00000000_8_sample_compute_10_cpp1_ii_b81a68a1(void)" (?sti__cudaRegisterAll_52_tmpxft_00001c68_00000000_8_sample_compute_10_cpp1_ii_b81a68a1@@YAXXZ) sample.cu.obj : error LNK2019: unresolved external symbol _cudaRegisterFatBinary@4 referenced in function "void __cdecl _sti_cudaRegisterAll_52_tmpxft_00001c68_00000000_8_sample_compute_10_cpp1_ii_b81a68a1(void)" (?sti__cudaRegisterAll_52_tmpxft_00001c68_00000000_8_sample_compute_10_cpp1_ii_b81a68a1@@YAXXZ) sample.cu.obj : error LNK2019: unresolved external symbol _cudaGetDeviceProperties@8 referenced in function _main sample.cu.obj : error LNK2019: unresolved external symbol _cudaGetDeviceCount@4 referenced in function _main sample.cu.obj : error LNK2019: unresolved external symbol _cudaConfigureCall@32 referenced in function _main C:\Users\t-sudhk\Documents\Visual Studio 2008\Projects\god\Debug\god.exe : fatal error LNK1120: 7 unresolved externals Results Build log was saved at "file://c:\Users\t-sudhk\Documents\Visual Studio 2008\Projects\god\god\Debug\BuildLog.htm" god - 8 error(s), 0 warning(s) I will be highly obliged if someone could help me. Thanks

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  • Servlet/JSP Flow Control: Enums, Exceptions, or Something Else?

    - by Christopher Parker
    I recently inherited an application developed with bare servlets and JSPs (i.e.: no frameworks). I've been tasked with cleaning up the error-handling workflow. Currently, each <form> in the workflow submits to a servlet, and based on the result of the form submission, the servlet does one of two things: If everything is OK, the servlet either forwards or redirects to the next page in the workflow. If there's a problem, such as an invalid username or password, the servlet forwards to a page specific to the problem condition. For example, there are pages such as AccountDisabled.jsp, AccountExpired.jsp, AuthenticationFailed.jsp, SecurityQuestionIncorrect.jsp, etc. I need to redesign this system to centralize how problem conditions are handled. So far, I've considered two possible solutions: Exceptions Create an exception class specific to my needs, such as AuthException. Inherit from this class to be more specific when necessary (e.g.: InvalidUsernameException, InvalidPasswordException, AccountDisabledException, etc.). Whenever there's a problem condition, throw an exception specific to the condition. Catch all exceptions via web.xml and route them to the appropriate page(s) with the <error-page> tag. enums Adopt an error code approach, with an enum keeping track of the error code and description. The descriptions can be read from a resource bundle in the finished product. I'm leaning more toward the enum approach, as an authentication failure isn't really an "exceptional condition" and I don't see any benefit in adding clutter to the server logs. Plus, I'd just be replacing one maintenance headache with another. Instead of separate JSPs to maintain, I'd have separate Exception classes. I'm planning on implementing "error" handling in a servlet that I'm writing specifically for this purpose. I'm also going to eliminate all of the separate error pages, instead setting an error request attribute with the error message to display to the user and forwarding back to the referrer. Each target servlet (Logon, ChangePassword, AnswerProfileQuestions, etc.) would add an error code to the request and redirect to my new servlet in the event of a problem. My new servlet would look something like this: public enum Error { INVALID_PASSWORD(5000, "You have entered an invalid password."), ACCOUNT_DISABLED(5002, "Your account has been disabled."), SESSION_EXPIRED(5003, "Your session has expired. Please log in again."), INVALID_SECURITY_QUESTION(5004, "You have answered a security question incorrectly."); private final int code; private final String description; Error(int code, String description) { this.code = code; this.description = description; } public int getCode() { return code; } public String getDescription() { return description; } }; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String sendTo = "UnknownError.jsp"; String message = "An unknown error has occurred."; int errorCode = Integer.parseInt((String)request.getAttribute("errorCode"), 10); Error errors[] = Error.values(); Error error = null; for (int i = 0; error == null && i < errors.length; i++) { if (errors[i].getCode() == errorCode) { error = errors[i]; } } if (error != null) { sendTo = request.getHeader("referer"); message = error.getDescription(); } request.setAttribute("error", message); request.getRequestDispatcher(sendTo).forward(request, response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } Being fairly inexperienced with Java EE (this is my first real exposure to JSPs and servlets), I'm sure there's something I'm missing, or my approach is suboptimal. Am I on the right track, or do I need to rethink my strategy?

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  • Preventing multiple repeat selection of synchronized Controls ?

    - by BillW
    The working code sample here synchronizes (single) selection in a TreeView, ListView, and ComboBox via the use of lambda expressions in a dictionary where the Key in the dictionary is a Control, and the Value of each Key is an Action<int. Where I am stuck is that I am getting multiple repetitions of execution of the code that sets the selection in the various controls in a way that's unexpected : it's not recursing : there's no StackOverFlow error happening; but, I would like to figure out why the current strategy for preventing multiple selection of the same controls is not working. Perhaps the real problem here is distinguishing between a selection update triggered by the end-user and a selection update triggered by the code that synchronizes the other controls ? Note: I've been experimenting with using Delegates, and forms of Delegates like Action<T>, to insert executable code in Dictionaries : I "learn best" by posing programming "challenges" to myself, and implementing them, as well as studying, at the same time, the "golden words" of luminaries like Skeet, McDonald, Liberty, Troelsen, Sells, Richter. Note: Appended to this question/code, for "deep background," is a statement of how I used to do things in pre C#3.0 days where it seemed like I did need to use explicit measures to prevent recursion when synchronizing selection. Code : Assume a WinForms standard TreeView, ListView, ComboBox, all with the same identical set of entries (i.e., the TreeView has only root nodes; the ListView, in Details View, has one Column). private Dictionary<Control, Action<int>> ControlToAction = new Dictionary<Control, Action<int>>(); private void Form1_Load(object sender, EventArgs e) { // add the Controls to be synchronized to the Dictionary // with appropriate Action<int> lambda expressions ControlToAction.Add(treeView1, (i => { treeView1.SelectedNode = treeView1.Nodes[i]; })); ControlToAction.Add(listView1, (i => { listView1.Items[i].Selected = true; })); ControlToAction.Add(comboBox1, (i => { comboBox1.SelectedIndex = i; })); } private void synchronizeSelection(int i, Control currentControl) { foreach(Control theControl in ControlToAction.Keys) { // skip the 'current control' if (theControl == currentControl) continue; // for debugging only Console.WriteLine(theControl.Name + " synchronized"); // execute the Action<int> associated with the Control ControlToAction[theControl](i); } } private void treeView1_AfterSelect(object sender, TreeViewEventArgs e) { synchronizeSelection(e.Node.Index, treeView1); } private void listView1_SelectedIndexChanged(object sender, EventArgs e) { // weed out ListView SelectedIndexChanged firing // with SelectedIndices having a Count of #0 if (listView1.SelectedIndices.Count > 0) { synchronizeSelection(listView1.SelectedIndices[0], listView1); } } private void comboBox1_SelectedValueChanged(object sender, EventArgs e) { if (comboBox1.SelectedIndex > -1) { synchronizeSelection(comboBox1.SelectedIndex, comboBox1); } } background : pre C# 3.0 Seems like, back in pre C# 3.0 days, I was always using a boolean flag to prevent recursion when multiple controls were updated. For example, I'd typically have code like this for synchronizing a TreeView and ListView : assuming each Item in the ListView was synchronized with a root-level node of the TreeView via a common index : // assume ListView is in 'Details View,' has a single column, // MultiSelect = false // FullRowSelect = true // HideSelection = false; // assume TreeView // HideSelection = false // FullRowSelect = true // form scoped variable private bool dontRecurse = false; private void treeView1_AfterSelect(object sender, TreeViewEventArgs e) { if(dontRecurse) return; dontRecurse = true; listView1.Items[e.Node.Index].Selected = true; dontRecurse = false; } private void listView1_SelectedIndexChanged(object sender, EventArgs e) { if(dontRecurse) return // weed out ListView SelectedIndexChanged firing // with SelectedIndices having a Count of #0 if (listView1.SelectedIndices.Count > 0) { dontRecurse = true; treeView1.SelectedNode = treeView1.Nodes[listView1.SelectedIndices[0]]; dontRecurse = false; } } Then it seems, somewhere around FrameWork 3~3.5, I could get rid of the code to suppress recursion, and there was was no recursion (at least not when synchronizing a TreeView and a ListView). By that time it had become a "habit" to use a boolean flag to prevent recursion, and that may have had to do with using a certain third party control.

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  • Event bubbling with img tags?

    - by Kenny Bones
    I did some googling and figured I'm probably experiencing so called "event bubbling" that I've never heard of but are not surprised by it's existance. I want it to fire only once and I'm wondering how to fix this. Basically, I have this small code snippet: $('.bggallery_images').click(function () { alert('test'); }); This is supposed to fire once from a php snippet that basically adds an image of each image from a specific folder. It then outputs an echo string where each image has the class of "bggallery_images". PHP snippet looks like this: <?php $dirname = "img"; $images = scandir($dirname); $ignore = Array(".", ".."); foreach($images as $file) { if(!in_array($file, $ignore)) { echo "<img class=\"bggallery_images\" src=\"$dirname/$file\" />"; }; } ?> This all generates the html markup that looks like this for each image: <img src="img/WhitePattern6.gif" class="bggallery_images"> What is happening here? Here's the rendered output from FireBug: <div id="gallery_lightbox" style="height: 215px; z-index: 4; display: block;"> <div id="close"></div> <h2><cufon class="cufon cufon-canvas" alt="Velg " style="width: 39px; height: 20px;"><canvas width="49" height="23" style="width: 49px; height: 23px; top: -4px; left: 0px;"></canvas><cufontext>Velg </cufontext></cufon><cufon class="cufon cufon-canvas" alt="bakgrunnsbilde" style="width: 123px; height: 20px;"><canvas width="129" height="23" style="width: 129px; height: 23px; top: -4px; left: 0px;"></canvas><cufontext>bakgrunnsbilde</cufontext></cufon></h2> <div class="bggallery_images">testererererer</div> <img src="img/Bakgrunner/4462-v4.jpg" class="bggallery_images"><img src="img/Bakgrunner/5922.gif" class="bggallery_images"><img src="img/Bakgrunner/BluePattern.gif" class="bggallery_images"><img src="img/Bakgrunner/Brown1.gif" class="bggallery_images"><img src="img/Bakgrunner/Brown2Pattern.jpg" class="bggallery_images"><img src="img/Bakgrunner/BrownPattern.jpg" class="bggallery_images"><img src="img/Bakgrunner/Brownn.gif" class="bggallery_images"><img src="img/Bakgrunner/GrayPattern.gif" class="bggallery_images"><img src="img/Bakgrunner/GreenPattern3.gif" class="bggallery_images"><img src="img/Bakgrunner/OrangePattern.gif" class="bggallery_images"><img src="img/Bakgrunner/PurplePattern.gif" class="bggallery_images"><img src="img/Bakgrunner/PurplePattern2.gif" class="bggallery_images"><img src="img/Bakgrunner/RedPattern3.gif" class="bggallery_images"><img src="img/Bakgrunner/RedPattern4.gif" class="bggallery_images"><img src="img/Bakgrunner/RedPattern5.gif" class="bggallery_images"><img src="img/Bakgrunner/Tiled_Wallpaper__Green_Texture_by_knitetgantt.png" class="bggallery_images"><img src="img/Bakgrunner/WhitePattern4.gif" class="bggallery_images"><img src="img/Bakgrunner/WhitePattern5.gif" class="bggallery_images"><img src="img/Bakgrunner/WhitePattern6.gif" class="bggallery_images"><img src="img/Bakgrunner/WhitePattern7.gif" class="bggallery_images"><img src="img/Bakgrunner/WhitePurple.jpg" class="bggallery_images"><img src="img/Bakgrunner/YellowPattern.gif" class="bggallery_images"><img src="img/Bakgrunner/vintage-wallpaper.jpg" class="bggallery_images"> </div>

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  • Thread Synchronisation 101

    - by taspeotis
    Previously I've written some very simple multithreaded code, and I've always been aware that at any time there could be a context switch right in the middle of what I'm doing, so I've always guarded access the shared variables through a CCriticalSection class that enters the critical section on construction and leaves it on destruction. I know this is fairly aggressive and I enter and leave critical sections quite frequently and sometimes egregiously (e.g. at the start of a function when I could put the CCriticalSection inside a tighter code block) but my code doesn't crash and it runs fast enough. At work my multithreaded code needs to be a tighter, only locking/synchronising at the lowest level needed. At work I was trying to debug some multithreaded code, and I came across this: EnterCriticalSection(&m_Crit4); m_bSomeVariable = true; LeaveCriticalSection(&m_Crit4); Now, m_bSomeVariable is a Win32 BOOL (not volatile), which as far as I know is defined to be an int, and on x86 reading and writing these values is a single instruction, and since context switches occur on an instruction boundary then there's no need for synchronising this operation with a critical section. I did some more research online to see whether this operation did not need synchronisation, and I came up with two scenarios it did: The CPU implements out of order execution or the second thread is running on a different core and the updated value is not written into RAM for the other core to see; and The int is not 4-byte aligned. I believe number 1 can be solved using the "volatile" keyword. In VS2005 and later the C++ compiler surrounds access to this variable using memory barriers, ensuring that the variable is always completely written/read to the main system memory before using it. Number 2 I cannot verify, I don't know why the byte alignment would make a difference. I don't know the x86 instruction set, but does mov need to be given a 4-byte aligned address? If not do you need to use a combination of instructions? That would introduce the problem. So... QUESTION 1: Does using the "volatile" keyword (implicity using memory barriers and hinting to the compiler not to optimise this code) absolve a programmer from the need to synchronise a 4-byte/8-byte on x86/x64 variable between read/write operations? QUESTION 2: Is there the explicit requirement that the variable be 4-byte/8-byte aligned? I did some more digging into our code and the variables defined in the class: class CExample { private: CRITICAL_SECTION m_Crit1; // Protects variable a CRITICAL_SECTION m_Crit2; // Protects variable b CRITICAL_SECTION m_Crit3; // Protects variable c CRITICAL_SECTION m_Crit4; // Protects variable d // ... }; Now, to me this seems excessive. I thought critical sections synchronised threads between a process, so if you've got one you can enter it and no other thread in that process can execute. There is no need for a critical section for each variable you want to protect, if you're in a critical section then nothing else can interrupt you. I think the only thing that can change the variables from outside a critical section is if the process shares a memory page with another process (can you do that?) and the other process starts to change the values. Mutexes would also help here, named mutexes are shared across processes, or only processes of the same name? QUESTION 3: Is my analysis of critical sections correct, and should this code be rewritten to use mutexes? I have had a look at other synchronisation objects (semaphores and spinlocks), are they better suited here? QUESTION 4: Where are critical sections/mutexes/semaphores/spinlocks best suited? That is, which synchronisation problem should they be applied to. Is there a vast performance penalty for choosing one over the other? And while we're on it, I read that spinlocks should not be used in a single-core multithreaded environment, only a multi-core multithreaded environment. So, QUESTION 5: Is this wrong, or if not, why is it right? Thanks in advance for any responses :)

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  • Broken corba object references

    - by cube
    I'm working on a homework and got stuck. The task is to serve objects using a default servant. But when I try to use the reference, weird things happen. Some part of corba prints a stack trace, but no exception is thrown. The problem happens when the server receives the reference and should call some method on it. The reference is then shortened and doesn't contain the object ID (which means that my servant implementation can't do anything reasonable). This is the implementation of the servant, where the problem appears: public class ModelFileImpl extends ModelFilePOA{ @Override public String getName() { try { return new String(_poa().reference_to_id(_this_object())); } catch (Throwable e) {} assert false; return null; } } If I take _this_object().toString() inside the try block and put it into dior -i i get this: ------IOR components----- TypeId : IDL:termproject/idl/ModelFile:1.0 TAG_INTERNET_IOP Profiles: Profile Id: 0 IIOP Version: 1.2 Host: 127.0.0.1 Port: 45954 Object key (URL): %AF%AB%CB%00%00%00%00%20Q%BA%F4%FF%00%00%00%01%00%00%00%00%00%00%00%01%0000%00%08RootPOA%00%00%00%00%08%00%00%00%02%00%00%00%00%14 Object key (hex): 0xAF AB CB 00 00 00 00 20 51 BA F4 FF 00 00 00 01 00 00 00 00 00 00 00 01 00 00 00 08 52 6F 6F 74 50 4F 41 00 00 00 00 08 00 00 00 02 00 00 00 00 14 -- Found 2 Tagged Components-- #0: TAG_CODE_SETS ForChar native code set Id: ISO8859_1 Char Conversion Code Sets: UTF8 , Unknown TCS: 10020 ForWChar native code set Id: UTF16 WChar Conversion Code Sets: Unknown TCS: 10100 Unknown tag : 38 however the part of server that makes the reference and the client see the reference as ------IOR components----- TypeId : IDL:termproject/idl/ModelFile:1.0 TAG_INTERNET_IOP Profiles: Profile Id: 0 IIOP Version: 1.2 Host: 127.0.0.1 Port: 45954 Object key (URL): %AF%AB%CB%00%00%00%00%20Q%BA%F4%FF%00%00%00%01%00%00%00%00%00%00%00%02%00%00%00%08RootPOA%00%00%00%00%09modelPoa%00%00%00%00%00%00%00%10testModel1.MyIDL%14 Object key (hex): 0xAF AB CB 00 00 00 00 20 51 BA F4 FF 00 00 00 01 00 00 00 00 00 00 00 02 00 00 00 08 52 6F 6F 74 50 4F 41 00 00 00 00 09 6D 6F 64 65 6C 50 6F 61 00 00 00 00 00 00 00 10 74 65 73 74 4D 6F 64 65 6C 31 2E 4D 79 49 44 4C 14 -- Found 2 Tagged Components-- #0: TAG_CODE_SETS ForChar native code set Id: ISO8859_1 Char Conversion Code Sets: UTF8 , Unknown TCS: 10020 ForWChar native code set Id: UTF16 WChar Conversion Code Sets: Unknown TCS: 10100 Unknown tag : 38 ("modelPoa" (the name of the poa working with default clients) and "testModel1.MyIDL" (the identifier of the object) in the object key are missing in the first one) I've tried sniffing the traffic and found out that the client still sends the correct reference. This is how i create the references: ret[i] = ModelFileHelper.narrow(modelFilePoa.create_reference_with_id(files[i].getBytes(), ModelFileHelper.id())); And this is how i set up the server: // init ORB ORB orb = ORB.init(args, null); // init POA POA poa = POAHelper.narrow(orb.resolve_initial_references("RootPOA")); // create the POA for the models. Policy[] policies = { poa.create_request_processing_policy(RequestProcessingPolicyValue.USE_DEFAULT_SERVANT), poa.create_servant_retention_policy(ServantRetentionPolicyValue.NON_RETAIN), poa.create_id_assignment_policy(IdAssignmentPolicyValue.USER_ID) }; POA modelPoa = poa.create_POA("modelPoa", poa.the_POAManager(), policies); modelPoa.the_POAManager().activate(); modelPoa.set_servant(new ModelFileImpl()); modelPoa.the_POAManager().activate(); ModelStoreImpl impl = new ModelStoreImpl(modelPoa); // create the object reference org.omg.CORBA.Object obj = poa.servant_to_reference(impl); // ... store the IOR file ... orb.run(); I'd be really grateful for any pointers (or references :-) )

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