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• Problem installing mod_jk on Ubuntu karmic apache httpd 2.2.12 and tomcat 6

  - by Deny Prasetyo

  I have a problem when configuring mod_jk on ubuntu i use apache httpd 2.2.12 and tomcat 6 I installed apache httpd and lib mod_jk from synaptic and use default configuration. Here my mod_jk.conf Load mod_jk module Update this path to match your modules location LoadModule jk_module /usr/lib/apache2/modules/mod_jk.so Where to find workers.properties Update this path to match your conf directory location JkWorkersFile /etc/apache2/workers.properties Where to put jk logs Update this path to match your logs directory location JkLogFile /etc/apache2/logs/mod_jk.log Set the jk log level [debug/error/info] JkLogLevel info Select the log format JkLogStampFormat "[%a %b %d %H:%M:%S %Y]" JkOptions indicate to send SSL KEY SIZE, JkOptions +ForwardKeySize +ForwardURICompat -ForwardDirectories JkRequestLogFormat set the request format JkRequestLogFormat "%w %V %T" Send everything for context /ws to worker ajp13 JkMount /themark ajp13 JkMount /themark/* ajp13 Send everything for context /jsp-examples to worker ajp13 JkMount /static ajp13 JkMount /static/* ajp13 Send everything for context /servelts-examples to worker ajp13 JkMount /servlets-examples ajp13 JkMount /servlets-examples/* ajp13 and this my workers.properties Define 1 real worker named ajp13 worker.list=ajp13 Set properties for worker named ajp13 to use ajp13 protocol, and run on port 8009 worker.ajp13.type=ajp13 worker.ajp13.host=localhost worker.ajp13.port=8009 worker.ajp13.lbfactor=50 worker.ajp13.cachesize=10 worker.ajp13.cache_timeout=600 worker.ajp13.socket_keepalive=1 worker.ajp13.socket_timeout=300 when i start apache httpd and tomcat 6. it seem that mod_jk load successfully and tomcat 6 recognized the ajp connector. here my tomcat 6 log INFO: Starting Coyote HTTP/1.1 on http-8080 Mar 29, 2010 11:48:34 AM org.apache.jk.common.ChannelSocket init INFO: JK: ajp13 listening on /0.0.0.0:8009 Mar 29, 2010 11:48:34 AM org.apache.jk.server.JkMain start INFO: Jk running ID=0 time=0/16 config=null here my mod_jk.log [Mon Mar 29 11:06:53 2010][6688:3499775792] [info] init_jk::mod_jk.c (2830): mod_jk/1.2.26 initialized [Mon Mar 29 11:16:59 2010][18277:1983043376] [info] init_jk::mod_jk.c (2830): mod_jk/1.2.26 initialized [Mon Mar 29 11:16:59 2010][18278:1983043376] [info] init_jk::mod_jk.c (2830): mod_jk/1.2.26 initialized but when i access http://localhost/themark it won't work. it seems that apache httpd can load the mod_jk module but it can listen the ajp. is there somebody ever had same problem? nb: i use the same config in windows using xampplite and it works well

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• Categories of tags

  - by Peter Rowell

  I'm starting a pro bono project that is the web interface to the world's largest collection of lute music and it's a challenging collection from several points of view. The pieces are largely from 1400 to 1600, but they range from the mid-1200's to present day. Needless to say, there is tremendous variability in how the pieces are categorized and who they are attributed to. It is obvious that any sort of rigid, DB-enforced hierarchy isn't going to work with this collection, so my thoughts turn to tags. But not all tags are the same. I'll have tags that represent a person/role (composer, translator, entabulator, etc.), tags that represent the instrument(s) the piece in written for, and tags that represent how the piece has been classified by any one of half a dozen different classification systems used over the centuries. We will be using a semi-controlled tag vocabulary to prevent runaway tag proliferation (e.g. del.icio.us), but I want to treat the tags as belonging to different groups. People tags should not be offered when the editor is doing instrument tagging, etc. Has anyone done something like this? I have several ways I can think of to do it, but if there is an existing system that is well-done it would save me time implementing/debugging. FWIW: This is a Django system and I'm looking at starting with Django-tagging and then hacking from there, possibly adding a category field or ...

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• Should we migrate from svn to Team Foundation Server 2010?

  - by Florian

  We are with 6 developer and currently use Visual Studio 2008 Professional with SVN and Visual SVN. As soon as vs2010 is released we will upgrade from vs2008 pro to vs2010 premium. However if Team Foundation Server has a proper source control included in vs2010 premium, then it does make sense to use it. We like SVN, but like tight integration of tools even better. On the internet information on SVN versus TFS 2010 seems to be scarce. Hence my question here. EDIT: This video looks very compelling. Is this marketing talk or real? Thank you all for your replies! I absolutely appreciate this. A little more background info. This is our current stack; vs2008 pro, Visual SVN, SVN, Jetbrain Teamcity. My main problem is that we use a lot of tools from different vendors which more or less integrate. Sometime more, mostly less. At least it takes a lot of time to set it up correctly. We currently do not use branches, but we want to. Therefore we have to set up SVN from scratch (we looked into it carefully). So let me rephrase my question: Should we set up SVN or start using TFS?

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• WCF done broke.

  - by SteveCav

  WCF is completely fouled up on my machine. I start a new sln in VS2008. Add a project (WCF Service Lib).Build the project (builds ok). debug the project -- it gets halfway through the progress bar and bombs out with the error below (real path changed to "my mex path" so codeproject doesn't think its spam). I'm assuming it's file permissions but don't know where to start. Any ideas?: Error: Cannot obtain Metadata from my mex path If this is a Windows (R) Communication Foundation service to which you have access, please check that you have enabled metadata publishing at the specified address. For help enabling metadata publishing, please refer to the MSDN documentation at somewhere unhelpful Exchange Error URI: my mex path Metadata contains a reference that cannot be resolved: 'my mex path'. Could not connect to my mex path. TCP error code 10061: No connection could be made because the target machine actively refused it 127.0.0.1:8731. Unable to connect to the remote server No connection could be made because the target machine actively refused it 127.0.0.1:8731HTTP GET Error URI: my mex path There was an error downloading 'my mex path'. Unable to connect to the remote server No connection could be made because the target machine actively refused it 127.0.0.1:8731

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• Qt - reading from a text file

  - by user289175

  Hello world, I have a table view with three columns; I have just passed to write into text file using this code QFile file("/home/hamad/lesson11.txt"); if(!file.open(QIODevice::WriteOnly)) { QMessageBox::information(0,"error",file.errorString()); } QString dd; for(int row=0; row < model->rowCount(); row++) { dd = model->item(row,0)->text() + "," + model->item(row,1)->text() + "," + model->item(row,2)->text(); QTextStream out(&file); out << dd << endl; } But I'm not succeed to read the same file again, I tried this code but I don't know where is the problem in it QFile file("/home/hamad/lesson11.txt"); QTextStream in(&file); QString line = in.readLine(); while(!in.atEnd()) { QStringList fields = line.split(","); model->appendRow(fields); } Any help please ?

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• When *not* to use prepared statements?

  - by Ben Blank

  I'm re-engineering a PHP-driven web site which uses a minimal database. The original version used "pseudo-prepared-statements" (PHP functions which did quoting and parameter replacement) to prevent injection attacks and to separate database logic from page logic. It seemed natural to replace these ad-hoc functions with an object which uses PDO and real prepared statements, but after doing my reading on them, I'm not so sure. PDO still seems like a great idea, but one of the primary selling points of prepared statements is being able to reuse them… which I never will. Here's my setup: The statements are all trivially simple. Most are in the form SELECT foo,bar FROM baz WHERE quux = ? ORDER BY bar LIMIT 1. The most complex statement in the lot is simply three such selects joined together with UNION ALLs. Each page hit executes at most one statement and executes it only once. I'm in a hosted environment and therefore leery of slamming their servers by doing any "stress tests" personally. Given that using prepared statements will, at minimum, double the number of database round-trips I'm making, am I better off avoiding them? Can I use PDO::MYSQL_ATTR_DIRECT_QUERY to avoid the overhead of multiple database trips while retaining the benefit of parametrization and injection defense? Or do the binary calls used by the prepared statement API perform well enough compared to executing non-prepared queries that I shouldn't worry about it? EDIT: Thanks for all the good advice, folks. This is one where I wish I could mark more than one answer as "accepted" — lots of different perspectives. Ultimately, though, I have to give rick his due… without his answer I would have blissfully gone off and done the completely Wrong Thing even after following everyone's advice. :-) Emulated prepared statements it is!

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• Behavior of retained property while holder is retained

  - by Aurélien Vallée

  Hello everyone, I am a beginner ObjectiveC programmer, coming from the C++ world. I find it very difficult to understand the memory management offered by NSObject :/ Say I have the following class: @interface User : NSObject { NSString* name; } @property (nonatomic,retain) NSString* name; - (id) initWithName: (NSString*) theName; - (void) release; @end @implementation User @synthesize name - (id) initWithName: (NSString*) theName { if ( self = [super init] ) { [self setName:theName]; } return self; } - (void) release { [name release]; [super release]; } @end No considering the following code, I can't understand the retain count results: NSString* name = [[NSString alloc] initWithCString:/*C string from sqlite3*/]; // (1) name retainCount = 1 User* user = [[User alloc] initWithName:name]; // (2) name retainCount = 2 [whateverMutableArray addObject:user]; // (3) name retainCount = 2 [user release]; // (4) name retainCount = 1 [name release]; // (5) name retainCount = 0 At (4), the retain count of name decreased from 2 to 1. But that's not correct, there is still the instance of user inside the array that points to name ! The retain count of a variable should only decrease when the retain count of a referring variable is 0, that is, when it is dealloced, not released.

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• Replace System.Net.Mail.MailMessage with manually created message and send it

  - by DEH

  I am trying to send emails that will bounce to a known mailbox. I plan to use VERP. Unfortunately the System.Net.Mail.MailMessage object does not allow me to precisely set the From: and Sender: headers within my email - it forces the values so that the resulting email contains the phrase 'on behalf of', and does not allow me fine control over the relevant mime headers. I therefore plan to manually write mime email messages directly to the pickup directory so that I can independently control the From and Sender headers. My dev box is a Vista box and therefore does not have an SMTP server. I would like to configure the dev box so that I have an SMTP server running on it. I can then turn off the SMTP server, write messages to the pickup dir, then turn on the SMPT server and see how the individual emails that I have written will behave (some delivered, some bounced to a bounce handler on a different email domain, as dictated by the Sender). Two questions: 1. Can anyone recommend an SMTP server that will monitor a pickup directory? 2. If I set headers as follows; From:[email protected]; Sender:[email protected] then the recipient will see the email as having come from [email protected] ( and won't see any reference to [email protected]), but if the mail bounces then the NDR will be sent to [email protected]). It's a real pain to have to do this, but I can't see any way of using System.Net.Mail.MailMessage without it messing up my headers.

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• Got a table of people, who I want to link to each other, many-to-many, with the links being bidirect

  - by dflock

  Imagine you live in very simplified example land - and imagine that you've got a table of people in your MySQL database: create table person ( person_id int, name text ) select * from person; +-------------------------------+ | person_id | name | +-------------------------------+ | 1 | Alice | | 2 | Bob | | 3 | Carol | +-------------------------------+ and these people need to collaborate/work together, so you've got a link table which links one person record to another: create table person__person ( person__person_id int, person_id int, other_person_id int ) This setup means that links between people are uni-directional - i.e. Alice can link to Bob, without Bob linking to Alice and, even worse, Alice can link to Bob and Bob can link to Alice at the same time, in two separate link records. As these links represent working relationships, in the real world they're all two-way mutual relationships. The following are all possible in this setup: select * from person__person; +---------------------+-----------+--------------------+ | person__person_id | person_id | other_person_id | +---------------------+-----------+--------------------+ | 1 | 1 | 2 | | 2 | 2 | 1 | | 3 | 2 | 2 | | 4 | 3 | 1 | +---------------------+-----------+--------------------+ For example, with person__person_id = 4 above, when you view Carol's (person_id = 3) profile, you should see a relationship with Alice (person_id = 1) and when you view Alice's profile, you should see a relationship with Carol, even though the link goes the other way. I realize that I can do union and distinct queries and whatnot to present the relationships as mutual in the UI, but is there a better way? I've got a feeling that there is a better way, one where this issue would neatly melt away by setting up the database properly, but I can't see it. Anyone got a better idea?

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• Can't override "From" address in MailMessage class using .config login credentials

  - by Jeff

  I'm updating some existing code that sends a simple email using .Net's SMTP classes. Sample code is below. The SMTP host is google and login info is contained in the App.config as shown below (obviously not real login info :)). The problem I'm having, and I haven't been able to find any answers Googling, is that I can NOT override the display of the "from" email address that's contained in the "username" attribute off the Network element in the config in the delivered email. In the line below that explicitly sets the From property off the myMailMessage object, that value, "[email protected]" does NOT display when the email is received. It still shows as "[email protected]" from the Network tag. However, the From name "Sparky" does appear in the email. I've tried adding a custom "From" header to the Header property of the myMailMessage but that didn't work either. Is there anyway to login to the smtp server, as shown below using the Network tag credentials, but in the actual email received override the From email address that's displayed? Sample code: MailMessage myMailMessage = new MailMessage(); myMailMessage.Subject = "My New Mail"; myMailMessage.Body = "This is my test mail to check"; myMailMessage.From = new MailAddress("[email protected]", "Sparky"); myMailMessage.To.Add(new MailAddress("[email protected]", "receiver name")); SmtpClient mySmtpClient = new SmtpClient(); mySmtpClient.Send(myMailMessage); in App.config: <system.net> <mailSettings> <smtp deliveryMethod="Network" from="[email protected]"> <network host="smtp.gmail.com" port="587" userName="[email protected]" password="mypassword" defaultCredentials="false"/> </smtp> </mailSettings> </system.net>

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• SAP related testing

  - by mgj

  Dear all, One notion that has been prevalent mostly as rumours for many aspiring programmers is that the testing phase of the SDLC(Software Development Life Cycle) is not that challenging and interesting as one's job as a tester after a period of time becomes monotonous because a person does the same thing repeatedly over and over again. Thats why many have this complexion of looking for a developers job rather than that of testers. Don't testers have a space for themselves in software companies to grow..? Please feel free to express your views for or against this. How true is that, could you please give e.g.'s of instances( need not be practical, even theoretical would suffice) which actually contradict this statement wrt a tester's career specifically wrt the SAP domain. E.g.'s from other domains are also welcome. This question is not meant to hurt someone's feelings who is in the testing domain. Its just that for e.g. in my case I want to know what actually would be the challenge's a tester could also face in real life situations.Something that would make their job also interesting and fun-filled. I myself am pro-testing and also interested in pursuing testing as a profession in a sw co, just curious to know more about it so...:) Thanks..:)

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• Why should I bother with unit testing if I can just use integration tests?

  - by CodeGrue

  Ok, I know I am going out on a limb making a statement like that, so my question is for everyone to convince me I am wrong. Take this scenario: I have method A, which calls method B, and they are in different layers. So I unit test B, which delivers null as a result. So I test that null is returned, and the unit test passes. Nice. Then I unit test A, which expects an empty string to be returned from B. So I mock the layer B is in, an empty string is return, the test passes. Nice again. (Assume I don't realize the relationship of A and B, or that maybe two differente people are building these methods) My concern is that we don't find the real problem until we test A and B togther, i.e. Integration Testing. Since an integration test provides coverage over the unit test area, it seems like a waste of effort to build all these unit tests that really don't tell us anything (or very much) meaningful. Why am I wrong?

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• How to use the Request URL/URL Rewriting For Localization in ASP.NET - Using an HTTP Module or Globa

  - by LocalizedUrlDMan

  I wanted to see if there is a way to use the request URL/URL rewriting to set the language a page is rendered in by examining a portion of the URL in ASP.NET. We have a site that already works with ASP.NET’s resource localization and user’s can change the language that they see pages/resources on the site in, however the current mechanism in not very search engine friendly since the language variations for each language all appear as one page. It would be much better if we could have pages like www.site.com/en-mx/realfolder/realpage.aspx that allow linking to culture specific versions of a page. I know lots of people have likely done localization through URL structures before and I wanted to know if one of your could share how to do this in the Global.asax file or with an HTTP Module (pointing to links to blog postings would be great too). We have a restriction that the site is based on ASP.NET 2.0 (so we can't used the 3.5+ features yet). Here is the example scenario: A real page exits at: www.site.com/realfolder/realpage.aspx The page has a mechanism for the user to change the language it is displayed in via a dropdown. There are search engine optimization and user links sharing benefits to doing this since people can link directly to a page that has content that is applicable to a certain language (this could also include right-to-left layouts for languages like Japanese). I would like to use an HTTP module to see if the first part of the URL after www.site.com, site.com, subdomain.site.com, etc. contains a valid culture code (e.g. en-us, es-mx) then use that value to set the localization culture of the page/resources based on that URL. So if the user accesses the URL www.site.com/en-MX/realfolder/realpage.aspx Then the page will render in Mexico’s variant of Spanish. If the user goes to www.site.com/realfolder/realpage.aspx directly the page would just use their browser’s language settings.

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• Classification: Dealing with Abstain/Rejected Class

  - by abner.ayala

  I am asking for your input and/help on a classification problem. If anyone have any references that I can read to help me solve my problem even better. I have a classification problem of four discrete and very well separated classes. However my input is continuous and has a high frequency (50Hz), since its a real-time problem. The circles represent the clusters of the classes, the blue line the decision boundary and Class 5 equals the (neutral/resting do nothing class). This class is the rejected class. However the problem is that when I move from one class to the other I activate a lot of false positives in the transition movements, since the movement is clearly non-linear. For example, every time I move from class 5 (neutral class) to 1 I first see a lot of 3's before getting to the 1 class. Ideally, I will want my decision boundary to look like the one in the picture below where the rejected class is Class =5. Has a higher decision boundary than the others classes to avoid misclassification during transition. I am currently implementing my algorithm in Matlab using naive bayes, kNN, and SVMs optimized algorithms using Matlab. Question: What is the best/common way to handle abstain/rejected classes classes? Should I use (fuzzy logic, loss function, should I include resting cluster in the training)?

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• What should a developer know before building a public web site?

  - by Joel Coehoorn

  What things should a programmer implementing the technical details of a web site address before making the site public? If Jeff Atwood can forget about HttpOnly cookies, sitemaps, and cross-site request forgeries all in the same site, what important thing could I be forgetting as well? I'm thinking about this from a web developer's perspective, such that someone else is creating the actual design and content for the site. So while usability and content may be more important than the platform, you the programmer have little say in that. What you do need to worry about is that your implementation of the platform is stable, performs well, is secure, and meets any other business goals (like not cost too much, take too long to build, and rank as well with Google as the content supports). Think of this from the perspective of a developer who's done some work for intranet-type applications in a fairly trusted environment, and is about to have his first shot and putting out a potentially popular site for the entire big bad world wide web. Also: I'm looking for something more specific than just a vague "web standards" response. I mean, HTML, JavaScript, and CSS over HTTP are pretty much a given, especially when I've already specified that you're a professional web developer. So going beyond that, Which standards? In what circumstances, and why? Provide a link to the standard's specification. This question is community wiki, so please feel free to edit that answer to add links to good articles that will help explain or teach each particular point.

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• Mocking an object that uses jni using EasyMock

  - by Visage

  So my class under test has code that looks braodly like this public void doSomething(int param) { Report report = new Report() ...do some calculations report.someMethod(someData) } my intention was to extract the construction of report into a protected method and override it to use a mock object that I could then test to ensure that someMethod had been called with the right data. So far so good. But Report isnt under my control, and to mkae things worse it uses JNI to load a library at runtime. If I do Report report = EasyMock.createMock(Report.class) then EasyMock attempts to use reflection to find out the class members, but this causes an attempt to load the JNI library, which fails (the JNI libraries are only available on UNIX). Im considering two things: a) Introduce a ReportWrapper interface with two implementations, one of which will delegate calls to an real Report (so basically a Proxy), and a second which will basically use a mock object. or b) instead of calling someMethod, call a protected method which will in turn call someMethod that I can override in a testing subclass. Either way it seems nasty. Any better ways?

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• Setting Position of source and listener has no effect

  - by Ben E

  Hi Guys, First time i've worked with OpenAL, and for the life of my i can't figure out why setting the position of the source doesn't have any effect on the sound. The sounds are in stero format, i've made sure i set the listener position, the sound is not realtive to the listener and OpenAL isn't giving out any error. Can anyone shed some light? Create Audio device ALenum result; mDevice = alcOpenDevice(NULL); if((result = alGetError()) != AL_NO_ERROR) { std::cerr << "Failed to create Device. " << GetALError(result) << std::endl; return; } mContext = alcCreateContext(mDevice, NULL); if((result = alGetError()) != AL_NO_ERROR) { std::cerr << "Failed to create Context. " << GetALError(result) << std::endl; return; } alcMakeContextCurrent(mContext); SoundListener::SetListenerPosition(0.0f, 0.0f, 0.0f); SoundListener::SetListenerOrientation(0.0f, 0.0f, -1.0f); The two listener functions call alListener3f(AL_POSITION, x, y, z); Real vec[6] = {x, y, z, 0.0f, 1.0f, 0.0f}; alListenerfv(AL_ORIENTATION, vec); I set the sources position to 1,0,0 which should be to the right of the listener but it has no effect alSource3f(mSourceHandle, AL_POSITION, x, y, z); Any guidance would be much appreciated

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• Polymorphic Numerics on .Net and In C#

  - by Bent Rasmussen

  It's a real shame that in .Net there is no polymorphism for numbers, i.e. no INumeric interface that unifies the different kinds of numerical types such as bool, byte, uint, int, etc. In the extreme one would like a complete package of abstract algebra types. Joe Duffy has an article about the issue: http://www.bluebytesoftware.com/blog/CommentView,guid,14b37ade-3110-4596-9d6e-bacdcd75baa8.aspx How would you express this in C#, in order to retrofit it, without having influence over .Net or C#? I have one idea that involves first defining one or more abstract types (interfaces such as INumeric - or more abstract than that) and then defining structs that implement these and wrap types such as int while providing operations that return the new type (e.g. Integer32 : INumeric; where addition would be defined as public Integer32 Add(Integer32 other) { return Return(Value + other.Value); } I am somewhat afraid of the execution speed of this code but at least it is abstract. No operator overloading goodness... Any other ideas? .Net doesn't look like a viable long-term platform if it cannot have this kind of abstraction I think - and be efficient about it. Abstraction is reuse.

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• SqlLite/Fluent NHibernate integration test harness initialization not repeatable after large data se

  - by Mark Rogers

  In one of my main data integration test harnesses I create and use Fluent NHibernate's SingleConnectionSessionSourceForSQLiteInMemoryTesting, to get a fresh session for each test. After each test, I close the connection, session, and session factory, and throw out the nested StructureMap container they came from. This works for almost any simple data integration test I can think, including ones that utilize Fluent NHib's PersistenceSpecification object. When I test the application's lengthy database bootstrapping process, which creates and saves thousands of domain objects, I start seeing issues. It's not that the setup and tear down fails, in fact, the test successfully bootstraps the in-memory database as the application would bootstrap the real database in the production environment. The problem occurs when the database bootstrapping occurs a second time on a new in-memory database, with a new session and session factory. The error is: NHibernate.StaleStateException : Unexpected row count: 0; expected: 1 The row count is indeed Unexpected, the row that the application under test is looking for should be in the session. You see, it's not that any data from the last integration test is sticking around, it's that for some reason the session just stops working mid-database-boostrap. And I've looked everywhere for a place I might be holding on to an old session and I can't find one. I've searched through the code for static singleton objects, but there are none anywhere near the code in question. I have a couple StructureMap InstanceScope singleton's but they are getting thrown out with each nested container that is lost after every test teardown. I've tried every possible variation on disposing and closing every object involved with each test teardown and it still fails on this lengthy database bootstrap. But non-bootstrap related database tests appear to work fine. I'm starting to run out of options and may have to surrender lengthy database integration tests in favor of WatiN-based acceptance tests. Can anyone give me any clue about how I can figure out why some of my SingleConnectionSessionSourceForSQLiteInMemoryTesting aren't repeatable? Any advice at all, about how to make an NHibernate SqlLite database integration test harness repeatable?

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• What is the right approach to checksumming UDP packets

  - by mr.b

  I'm building UDP server application in C#. I've come across a packet checksum problem. As you probably know, each packet should carry some simple way of telling receiver if packet data is intact. Now, UDP already has 2-byte checksum as part of header, which is optional, at least in IPv4 world. Alternative method is to have custom checksum as part of data section in each packet, and to verify it on receiver. My question boils down to: is it better to rely on (optional) checksum in UDP packet header, or to make a custom checksum implementation as part of packet data section? Perhaps the right answer depends on circumstances (as usual), so one circumstance here is that, even though code is written and developed in .NET on Windows, it might have to run under platform-independent Mono.NET, so eventual solution should be compatible with other platforms. I believe that custom checksum algorithm would be easily portable, but I'm not so sure about the first one. Any thoughts? Also, shouts about packet checksumming in general are welcome.

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• ColdFusion blank page in IE7 on refresh?

  - by richardtallent

  I'm new to ColdFusion, have a very basic problem that's really slowing me down. I'm making edits in a text editor and refreshing the page in web browsers for testing. Standard web dev stuff, no browser-sniffing, redirection, or other weirdness, and no proxies involved. When I refresh the page in Chrome or Firefox, everything works fine, but when I refresh in IE7, I get a blank page. View Source shows me: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=utf-8"></HEAD> <BODY></BODY></HTML> That's it. While I am rendering to the transitional DTD, the real head contains a title, etc. My development server is CF 9, production is 8. This problem has been happening in both. Seems it may only be happening on pages that are the the result of a POST action. I've never experienced this in ASP.NET (my usual development environment) using the same browsers.

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• How does the last integer promotion rule ever get applied in C?

  - by SiegeX

  6.3.1.8p1: Otherwise, the integer promotions are performed on both operands. Then the following rules are applied to the promoted operands: If both operands have the same type, then no further conversion is needed. Otherwise, if both operands have signed integer types or both have unsigned integer types, the operand with the type of lesser integer conversion rank is converted to the type of the operand with greater rank. Otherwise, if the operand that has unsigned integer type has rank greater or equal to the rank of the type of the other operand, then the operand with signed integer type is converted to the type of the operand with unsigned integer type. Otherwise, if the type of the operand with signed integer type can represent all of the values of the type of the operand with unsigned integer type, then the operand with unsigned integer type is converted to the type of the operand with signed integer type. Otherwise, both operands are converted to the unsigned integer type corresponding to the type of the operand with signed integer type. For the bolded rule to be applied it would seem to imply you need to have have an unsigned interger type who's rank is less than the signed integer type and the signed integer type cannot hold all the values of the unsigned integer type. Is there a real world example of such a case or is this statement serving as a catch-all to cover all possible permutations?

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• mod_cgi , mod_fastcgi, mod_scgi , mod_wsgi, mod_python, FLUP. I don't know how many more. what is mo

  - by claws

  I recently learnt Python. I liked it. I just wanted to use it for web development. This thought caused all the troubles. But I like these troubles :) Coming from PHP world where there is only one way standardized. I expected the same and searched for python & apache. http://stackoverflow.com/questions/449055/setting-up-python-on-windows-apache says Stay away from mod_python. One common misleading idea is that mod_python is like mod_php, but for python. That is not true. So what is equivalent of mod_php in python? I need little clarification on this one http://stackoverflow.com/questions/219110/how-python-web-frameworks-wsgi-and-cgi-fit-together CGI, FastCGI and SCGI are language agnostic. You can write CGI scripts in Perl, Python, C, bash, or even Assembly :). So, I guess mod_cgi , mod_fastcgi, mod_scgi are their corresponding apache modules. Right? WSGI is some kind of optimized/improved inshort an efficient version specifically designed for python language only. In order to use this mod_wsgi is a way to go. right? This leaves out mod_python. What is it then? Apache - mod_fastcgi - FLUP (via CGI protocol) - Django (via WSGI protocol) Flup is another way to run with wsgi for any webserver that can speak FCGI, SCGI or AJP What is FLUP? What is AJP? How did Django come in the picture? These questions raise quetions about PHP. How is it actually running? What technology is it using? mod_php & mod_python what are the differences? In future if I want to use Perl or Java then again will I have to get confused? Kindly can someone explain things clearly and give a Complete Picture.

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• Slow retrieval of data in SQLITE takes a long using ContentProvider

  - by Arlyn

  I have an application in Android (running 4.0.3) that stores a lot of data in Table A. Table A resides in SQLite Database. I am using a ContentProvider as an abstraction layer above the database. Lots of data here means almost 80,000 records per month. Table A is structured like this: String SQL_CREATE_TABLE = "CREATE TABLE IF NOT EXISTS " + TABLE_A + " ( " + COLUMN_ID + " INTEGER PRIMARY KEY NOT NULL" + "," + COLUMN_GROUPNO + " INTEGER NOT NULL DEFAULT(0)" + "," + COLUMN_TIMESTAMP + " DATETIME UNIQUE NOT NULL" + "," + COLUMN_TAG + " TEXT" + "," + COLUMN_VALUE + " REAL NOT NULL" + "," + COLUMN_DEVICEID + " TEXT NOT NULL" + "," + COLUMN_NEW + " NUMERIC NOT NULL DEFAULT(1)" + " )"; Here is the index statement: String SQL_CREATE_INDEX_TIMESTAMP = "CREATE INDEX IF NOT EXISTS " + TABLE_A + "_" + COLUMN_TIMESTAMP + " ON " + TABLE_A + " (" + COLUMN_TIMESTAMP + ") "; I have defined the columns as well as the table name as String Constants. I am already experiencing significant slow down when retrieving this data from Table A. The problem is that when I retrieve data from this table, I first put it in an ArrayList and then I display it. Obviously, this is possibly the wrong way of doing things. I am trying to find a better way to approach this problem using a ContentProvider. But this is not the problem that bothers me. The problem is for some reason, it takes a lot longer to retrieve data from other tables which have only upto 12 records maximum. I see this delay increase as the number of records in Table A increase. This does not make any sense. I can understand the delay if I retrieve data from Table A, but why the delay in retrieving data from other tables. To clarify, I do not experience this delay if Table A is empty or has less than 3000 records. What could be the problem?

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• Integer Surrogate Key?

  - by CitadelCSAlum

  I need something real simple, that for some reason I am unable to accomplish to this point. I have also been unable to Google the answer surprisingly. I need to number the entries in different tables uniquely. I am aware of AUTO INCREMENT in MySQL and that it will be involved. My situation would be as follows If I had a table like Table EXAMPLE ID - INTEGER FIRST_NAME - VARCHAR(45) LAST_NAME - VARCHAR(45) PHONE - VARCHAR(45) CITY - VARCHAR(45) STATE - VARCHAR(45) ZIP - VARCHAR(45) This would be the setup for the table where ID is an integer that is auto-incremented every time an entry is inserted into the table. The thing I need is that I do not want to have to account for this field when inserting data into the database. From my understanding this would be a surrogate key, that I can tell the database to automatically increment and I do not have to include it in the INSERT STATEMENT so instead of INSERT INTO EXAMPLE VALUES (2,'JOHN','SMITH',333-333-3333,'NORTH POLE'.... I can leave out the first ID column and just write something like INSERT INTO EXAMPLE VALUES ('JOHN','SMITH'.....etc) Notice I Wouldnt have to define the ID column... I know this is a very common task to do, but for some reason I cant get to the bottom of it. I am using MySQL, just to clarify. Thanks alot

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