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  • Reference inherited class's <T>ype in a derived class

    - by DRapp
    I don't know if its possible or not, but here's what I need. I'm toying around with something and want to know if its possible since you can't create your own data type based on a sealed type such as int, Int32, Int64, etc. I want to create a top-level class that is defined of a given type with some common stuff. Then, derive this into two subclasses, but in this case, each class is based on either and int or Int64 type. From THAT instance, create an instance of either one and know its yped basis for parameter referenc / return settings. So when I need to create an instance of the "ThisClass", I don't have to know its type basis of either int or Int64, yet IT will know the type and be able to allow methods/functions to be called with the typed... This way, If I want to change my ThisClass definition from SubLevel1 to SubLevel2, I don't have to dance around all different data type definitions. Hope this makes sense.. public class TopLevel<T> { ... } pubic class SubLevel1 : TopLevel<int> { ... } public class SubLevel2 : TopLevel<Int64> { ... } public class ThisClass : SubLevel1 { ... public <based on the Int data type from SubLevel1> SomeFunc() { return <the Int value computed>; } }

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  • Mocking with Boost::Test

    - by Billy ONeal
    Hello everyone :) I'm using the Boost::Test library for unit testing, and I've in general been hacking up my own mocking solutions that look something like this: //In header for clients struct RealFindFirstFile { static HANDLE FindFirst(LPCWSTR lpFileName, LPWIN32_FIND_DATAW lpFindFileData) { return FindFirstFile(lpFileName, lpFindFileData); }; }; template <typename FirstFile_T = RealFindFirstFile> class DirectoryIterator { //.. Implementation } //In unit tests (cpp) #define THE_ANSWER_TO_LIFE_THE_UNIVERSE_AND_EVERYTHING 42 struct FakeFindFirstFile { static HANDLE FindFirst(LPCWSTR lpFileName, LPWIN32_FIND_DATAW lpFindFileData) { return THE_ANSWER_TO_LIFE_THE_UNIVERSE_AND_EVERYTHING; }; }; BOOST_AUTO_TEST_CASE( MyTest ) { DirectoryIterator<FakeFindFirstFile> LookMaImMocked; //Test } I've grown frustrated with this because it requires that I implement almost everything as a template, and it is a lot of boilerplate code to achieve what I'm looking for. Is there a good method of mocking up code using Boost::Test over my Ad-hoc method? I've seen several people recommend Google Mock, but it requires a lot of ugly hacks if your functions are not virtual, which I would like to avoid. Oh: One last thing. I don't need assertions that a particular piece of code was called. I simply need to be able to inject data that would normally be returned by Windows API functions.

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  • virtualbox - debian with no-ip

    - by JohnWong
    Hi. I have VB on my XP SP3. I am running one guest OS, Debian. I installed it using the 150MB, and everything seems to work fine. I am using 3.1.6 VB The purpose of this server is running php, mysql and django project. So I need access both locally and externally. I usually do it with my no-ip. I have experience with Ubuntu server, and using noip2 was a cake. I had this "domain" xxx.no-ip.org. I need this to be use on my debian server, so that I can type xxx.no-ip.org into the firefox (on my xp). I checked ifconfig, pstree. They showed that debian grabbed the right ip (it matched with my ip), and pstree showed noip2 has already been activated (under init.d) But I can't access to xxx.no-ip.org from my windows in firefox how come? back in the days when I used ubuntu as its own installation (instead of VM), noip2 worked like a cake without any twist. Any thoughts? Thank you!

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  • Ruby on Rails: How to sanitize a string for SQL when not using find and other built-in methods?

    - by williamjones
    I'm trying to sanitize a string that involves user input without having to resort to manually crafting my own possibly buggy regex if possible. There are a number of methods in Rails that can allow you to enter in native SQL commands, how do people escape user input for those? The question I'm asking is a broad one, but in my particular case, I'm working with a column in my Postgres database that Rails does not natively understand as far as I know, the tsvector, which holds plain text search information. Rails is able to write and read from it as if it's a string, however, unlike a string, it doesn't seem to be automatically escaping it when I do things like vector= inside the model. For example, when I do model.name='::', where name is a string, it works fine. When I do model.vector='::' it errors out: ActiveRecord::StatementInvalid: PGError: ERROR: syntax error in tsvector: "::" "vectors" = E'::' WHERE "id" = 1 This seems to be a problem caused by lack of escaping of the semicolons, and I can manually set the vector='\:\:' fine. I also had the bright idea, maybe I can just call something like: ActiveRecord::Base.connection.execute "UPDATE medias SET vectors = ? WHERE id = 1", "::" However, this syntax doesn't work, because the raw SQL commands don't have access to find's method of escaping and inputting strings by using the ? mark. This strikes me as the same problem as calling connection.execute with any type of user input, as it all boils down to sanitizing the strings, but I can't seem to find any way to manually call Rails' SQL string sanitization methods. Can anyone provide any advice?

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  • HTTP 1.0 vs 1.1

    - by Jason Baker
    Could somebody give me a brief overview of the differences between HTTP 1.0 and HTTP 1.1? I've spent some time with both of the RFCs, but haven't been able to pull out a lot of difference between them. Wikipedia says this: HTTP/1.1 (1997-1999) Current version; persistent connections enabled by default and works well with proxies. Also supports request pipelining, allowing multiple requests to be sent at the same time, allowing the server to prepare for the workload and potentially transfer the requested resources more quickly to the client. But that doesn't mean a lot to me. I realize this is a somewhat complicated subject, so I'm not expecting a full answer, but can someone give me a brief overview of the differences at a bit lower level? By this I mean that I'm looking for the info I would need to know to implement either an HTTP server or application. I realize that this can be a somewhat complicated subject (based on what I know about HTTP as of right now), so I'm not necessarily looking for a full answer. I'm really more looking for a nudge in the right direction so that I can figure it out on my own.

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  • How to install PySide v0.3.1 on Mac OS X?

    - by ivo
    I'm trying to install PySide v0.3.1 in Mac OS X, for Qt development in python. As a pre-requisite, I have installed CMake and the Qt SDK. I have gone through the documentation and come up with the following installation script: export PYSIDE_BASE_DIR="<my_dir>" export APIEXTRACTOR_DIR="$PYSIDE_BASE_DIR/apiextractor-0.5.1" export GENERATORRUNNER_DIR="$PYSIDE_BASE_DIR/generatorrunner-0.4.2" export SHIBOKEN_DIR="$PYSIDE_BASE_DIR/shiboken-0.3.1" export PYSIDE_DIR="$PYSIDE_BASE_DIR/pyside-qt4.6+0.3.1" export PYSIDE_TOOLS_DIR="$PYSIDE_BASE_DIR/pyside-tools-0.1.3" pushd . cd $APIEXTRACTOR_DIR cmake . cd $GENERATORRUNNER_DIR cmake -DApiExtractor_DIR=$APIEXTRACTOR_DIR . cd $SHIBOKEN_DIR cmake -DApiExtractor_DIR=$APIEXTRACTOR_DIR -DGeneratorRunner_DIR=$GENERATORRUNNER_DIR . cd $PYSIDE_DIR cmake -DShiboken_DIR=$SHIBOKEN_DIR/libshiboken -DGENERATOR=$GENERATORRUNNER_DIR . cd $PYSIDE_TOOLS_DIR cmake . popd Now, I don't know if this installation script is ok, but apparently everything works fine. Each component (apiextractor, generatorrunner, shiboken, pyside-qt and pyside-tools) gets compiled into its own directory. The problem is that I don't quite understand how PySide gets into the system's python environment. In fact, when I start a python shell, I cannot import PySide: >>> import PySide Traceback (most recent call last): File "<stdin>", line 1, in <module> ImportError: No module named PySide Note: I am aware of the Installing PySide - OSX question, but that question is not relevant anymore, because it is about a specific a dependency on the Boost libraries, but with version 0.3.0 PySide moved from a Boost based source code to a CPython one.

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  • How to embed multiple jQuery line of code in custom HtmlHelpers ASP.NET MVC

    - by embarus
    I 've tried to create my own HTML Helper which work fine for my need but I can't embed many lines of jQuery code in my extension HtmlHelpers class. I've tried @ literal for jQuery code I doesn't work or I need to escape every line of code that I thing I not good for multiple line of code. I don't know if there is another way to achieve this problem like << Therefore, I need to include jQuery plugin file and put implement script after HTML tag. I find it would be convenience if I could put every in HTML helper and put a single line of code in aspx page for example <%= Html.ParentChildSelectList(string parentName, string childName, IEnumerable parentViewData, IEnumerable childViewData, int parentSize, in childSize) % The following code is the way that I used now. the .aspx page Category model.CategoryID)% , new { size = 10 })% model.SubcategoryID,"subcategory") % model.SubcategoryID)% , new { size = 10 })% <script type="text/javascript"> jQuery.sarapadchang.parentChildSelectList( { parentId : "CategoryID" , childId : "SubcategoryID", actionName : "GetSubcategoryList", controllerName : "Json" } ); </script> I put in head tag to include ParentChildSelectList.js the following code for ParentChildSelectList.js (function($) { $.sarapadchang = { parentChildSelectList: function(options) { // $("#CategoryID option").click(function() $("#" + options.parentId).find("option").click(function() { $("#" + options.childId).empty(); //clear data $("#" + options.childId).append('<option>loading...</option>'); $.post("/" + options.controllerName + "/" + options.actionName + "/" + $(this).attr('value'), "", function(data) { var html = ""; $.each(data, function(index, entry) { html += '<option value="' + entry['Value'] + '">' + entry['Text'] + '</option>'; } ); $("#" + options.childId).empty() $("#" + options.childId).append(html); }, "json"); //end getJson }); })(jQuery); To illustrate you, I've attached simple solution, please follow this link. http://www.thaileaguefc.net/ParentChildSelectList.rar Please accept my apologies if my English is difficult to understand. I am looking forward to hearing from you. Your faithfully, Theeranit

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  • Keeping track of leading zeros with BitSet in Java

    - by Ryan
    So, according to this question there are two ways to look at the size of a BitSet. size(), which is legacy and not really useful. I agree with this. The size is 64 after doing: BitSet b = new BitSet(8); length(), which returns the index of the highest set bit. In the above example, length() will return 0. This is somewhat useful, but doesn't accurately reflect the number of bits the BitSet is supposed to be representing in the event you have leading zeros. The information I'm dealing with rarely(if ever) falls evenly into 8-bit bytes, and the leading 0s are just as important to me as the 1s. I have some data fields that are 333 bits long, some that are 20, etc. Is there a better way to deal with bit-level details in Java that will keep track of leading zeros? Otherwise, I'm going to have to 'roll my own', so to speak. To which I have a few ideas already, but I'd prefer not to reinvent the wheel if possible.

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  • using jquery (json) to get ajax database entries in wordpress - PHP not working

    - by Matt Facer
    I'm writing a plugin for my wordpress site and am having trouble understanding the jquery ajax requests. In a nutshell, I am trying to get some user meta data loaded when the page loads. So in my javascript file I have a line: $.getJSON("http://mysite.co.uk/wp-content/plugins/myplugin/ajax/ajax.php?action=test", function(json) { // do stuff }); So the above DOES get called, but it's the PHP code I'm having trouble with. In the file ajax.php, I am making a database call, but NONE of the usual class information is available. I've tried including the admin ajax page, various other pages from my own plugin (which does work).... not sure what else to do! The database call method works OK in my plugin code.. but I guess that the ajax.php file is outside the WP framework so that's why it's not working... but I don't know how to get it IN the framework!? I just need to use the $wpdb->get_results($sql); command to get my SQL. The error returned from firebug is that I am making a call to an undefined function. Thanks for any help... $.getJSON("http://www.offbeatattractions.co.uk/wp-content/plugins/wp-geo-extended/ajax/change_location.php?action=listpoints", function(json) { alert(json.Locations.length);

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  • AS3: Array of objects parsed from XML remains with zero length

    - by Joel Alejandro
    I'm trying to parse an XML file and create an object array from its data. The data is converted to MediaAlbum classes (class of my own). The XML is parsed correctly and the object is loaded, but when I instantiate it, the Albums array is of zero length, even when the data is loaded correctly. I don't really know what the problem could be... any hints? import Nem.Media.*; var mg:MediaGallery = new MediaGallery("test.xml"); trace(mg.Albums.length); MediaGallery class: package Nem.Media { import flash.net.URLRequest; import flash.net.URLLoader; import flash.events.*; public class MediaGallery { private var jsonGalleryData:Object; public var Albums:Array = new Array(); public function MediaGallery(xmlSource:String) { var loader:URLLoader = new URLLoader(); loader.load(new URLRequest(xmlSource)); loader.addEventListener(Event.COMPLETE, loadGalleries); } public function loadGalleries(e:Event):void { var xmlData:XML = new XML(e.target.data); var album; for each (album in xmlData.albums) { Albums.push(new MediaAlbum(album.attribute("name"), album.photos)); } } } } XML test source: <gallery <albums <album name="Fútbol 9" <photos <photo width="600" height="400" filename="foto1.jpg" / <photo width="600" height="400" filename="foto2.jpg" / <photo width="600" height="400" filename="foto3.jpg" / </photos </album <album name="Fútbol 8" <photos <photo width="600" height="400" filename="foto4.jpg" / <photo width="600" height="400" filename="foto5.jpg" / <photo width="600" height="400" filename="foto6.jpg" / </photos </album </albums </gallery

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  • Detecting death of spawned process using Window CRT

    - by Michael Tiller
    Executive summary: I need a way to determine whether a Windows process I've spawned via _spawnl and am communicating with using FDs from _pipe has died. Details: I'm using the low-level CRT function in Windows (_eof, _read) to communicate with a process that was spawned via a call to _spawnl (with the P_NOWAIT) flag. I'm using _pipe to create file descriptors to communicate with this spawned process and passing those descriptors (the FD #) to it on the command line. It is worth mentioning that I don't control the spawned process. It's a black box to me. It turns out that the process we are spawning occasionally crashes. I'm trying to make my code robust to this by detecting the crash. Unfortunately, I can't see a way to do this. It seems reasonable to me to expect that a call to _eof or _read on one of those descriptors would return an error status (-1) if the process had died. Unfortunately, that isn't the case. It appears that the descriptors have a life of their own independent of the spawned process. So even though the process on the other end is dead, I get no error status on the file descriptor I'm using to communicate with it. I've got the PID for the nested process (returned from the _spanwnl call) but I don't see anything I can do with that. My code works really well except for one thing. I can't detect whether the spawned process is simply busy computing me an answer or has died. If I can use the information from _pipe and _spawnl to determine if the spawned process is dead, I'll be golden. Suggestions very welcome. Thanks in advance. UPDATE: I found a fairly simple solution and added it as the selected answer.

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  • CSS Parser - Insert mtimes

    - by brad
    What command line tool can I use to automatically insert mtimes into urls in my css files for the purposes of breaking the cache? /* before */ .example { background: url(example.jpg); } /* after */ .example { background: url(example.jpg?1271298451); } Also, I would like this tool to spit out the latest mtime as the css files mtime. (If the css file is still cached then the new urls will not get to the client.) In searching the web, I have found very few tools that can do this. I am even considering rolling my own, but have found very little in the way of css parsers that are actively maintained. A candidate should be: fast (I don't want to wait 30 seconds on deployment) command line accessible (something like "cat foo.css bar.css | cssmtime out.css") What I've found so Far yui compressor - initially I thought I would extend the yui compressor to do this, but found that it is implemented as a bunch of regex's and not a parser. csstidy - last release was in 2007 and development has been suspended, but does have an option for inserting mtimes (also written in php, something I have no experience in) cssutils - python sac implementation - seems to be actively maintained, but also seems like overkill for my needs. Also, written in python which I have experience with csspool - ruby sac implementation - I don't know much ruby, but would like to learn other sac implementations - There are several java implementations, and a c implementation neither of which I know much about What's your experience? Have you used any of these libraries? Was the experience positive? Would you recommend I go with them for my purposes?

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  • How can I read a DBF file with incorrectly defined column data types using ADO.NET?

    - by Jason
    I have a several DBF files generated by a third party that I need to be able to query. I am having trouble because all of the column types have been defined as characters, but the data within some of these fields actually contain binary data. If I try to read these fields using an OleDbDataReader as anything other than a string or character array, I get an InvalidCastException thrown, but I need to be able to read them as a binary value or at least cast/convert them after they are read. The columns that actually DO contain text are being returned as expected. For example, the very first column is defined as a character field with a length of 2 bytes, but the field contains a 16-bit integer. I have written the following test code to read the first column and convert it to the appropriate data type, but the value is not coming out right. The first row of the database has a value of 17365 (0x43D5) in the first column. Running the following code, what I end up getting is 17215 (0x433F). I'm pretty sure it has to do with using the ASCII encoding to get the bytes from the string returned by the data reader, but I'm not sure of another way to get the value into the format that I need, other that to write my own DBF reader and bypass ADO.NET altogether which I don't want to do unless I absolutely have to. Any help would be greatly appreciated. byte[] c0; int i0; string con = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\ASTM;Extended Properties=dBASE III;User ID=Admin;Password=;"; using (OleDbConnection c = new OleDbConnection(con)) { c.Open(); OleDbCommand cmd = c.CreateCommand(); cmd.CommandText = "SELECT * FROM astm2007"; OleDbDataReader dr = cmd.ExecuteReader(); while (dr.Read()) { c0 = Encoding.ASCII.GetBytes(dr.GetValue(0).ToString()); i0 = BitConverter.ToInt16(c0, 0); } dr.Dispose(); }

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  • Lightweight development web server with support for PHP v2

    - by David
    In line with this question: http://stackoverflow.com/questions/171655/lightweight-web-app-server-for-php The above question has been asked numerous times and answered exactly the same in all the cases I've found using google. My question is similar to a degree but with a different desired goal: On demand development instances. I have come up with a somewhat questionable solution to host arbitrary directories in my user account for the purpose of development testing. I am not interested in custom vhosts but looking to emulate the behaviour I get when using paster or mongrel for Python & Ruby respectively. Ubuntu 9.10 TOXIC@~/ APACHE_RUN_USER=$USER APACHE_RUN_GROUP=www-data apache2 -d ~/Desktop/ -c "Listen 2990" Is there a better solution, could I do something similar with nginix or lighttpd? Note: The above won't work correctly for stock environments without a copied & altered httpd.conf. Update: The ideal goal is to mimic Paster, Webbrick, and Mongrel for rapid local development hosting. For those light weight servers, it takes less then a minute to get a working instance running ( not factoring any DB support ). Apache2 vhost is great but I've been using Apache2 for over ten years and it would be some sort of abomination hack to setup a new entry in /etc/hosts unless you have your own DNS, in which case a wildcard subdomain setup would probably work great. EXCEPT one more problem, it's pretty easy for me to know what is being hosted ( ex. by paster or mongeral ) just doing a sudo netstat -tulpn while there would be a good possibility of confusion in figure out which vhost is what.

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  • Can I create template-based library objects in Dreamweaver CS5?

    - by Danjah
    At work we need two 'streams' of template. The first are general layout templates, like the ones already available in the MX through CS5 packages (except we'd have our own customised ones). The second are more granular objects, some of which are functional. In both cases, I don't want Jimmy to be able to wreak havoc inside anything other than the 'editable regions' which make up the templates. Now this is fine if I stick with the first scenario (layout templates) where there's simply a big chunk of editable region for good ole Jim to sprawl into, think of this as the 'body content' area. But I really do need these granular library (or snippet) objects to work in the same way. Unfortunately with my attempts so far they don't work as I'd have thought - perhaps for good reason? When I create a blank template and throw in my chunk of HTML (unobstrusive JS and external CSS use selectors in this HTML to provide style and function) and save it as a new library item or snippet, all looks well. Then I create a new document based on a layout template and save it as a plain html file (still all good so far). Next I drop in my custom library item... still all good... but then I go to save the document and it only allows me to save it as a new template! I expected it would just allow me to save it as HTML and have it simply respect the defined editable regions, as happens in the containing page 'body content' editable region. Apologies if that got specific and technical quite quickly, but it is quite particular. If you want some example files lemme know and I'll zip some up. Many thanks :) p.s It is not a requirement that library objects must somehow inject their dependency files into the newly created page - I already know what they'll be. Also, I know I must 'detatch from original' once I drop a library item into a document which then allows customisation of the library object.

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  • php - disconnecting and connecting to multiple databases

    - by Phil Jackson
    Hi, I want to be able to switch from the current db to multiple dbs though a loop: $query = mysql_query("SELECT * FROM `linkedin` ORDER BY id", $CON ) or die( mysql_error() ); if( mysql_num_rows( $query ) != 0 ) { $last_update = time() / 60; while( $rows = mysql_fetch_array( $query ) ) { $contacts_db = "NNJN_" . $rows['email']; // switch to the contacts db mysql_select_db( $contacts_db, $CON ); $query = mysql_query("SELECT * FROM `linkedin` WHERE token = '" . TOKEN . "'", $CON ) or die( mysql_error() ); if( mysql_num_rows( $query ) != 0 ) { mysql_query("UPDATE `linkedin` SET last_update = '{$last_update}' WHERE token = '" . TOKEN . "'", $CON ) or die( mysql_error() ); }else{ mysql_query("INSERT INTO `linkedin` (email, token, username, online, away, last_update) VALUES ('" . EMAIL . "', '" . TOKEN . "', '" . USERNAME . "', 'true', 'false', '$last_update')", $CON ) or die( mysql_error() ); } } mysql_free_result( $query ); } // switch back to your own mysql_select_db( USER_DB, $CON ); It does insert and update details from the other databases but it also inserts and edits data from the current users database which I dont want. Any ideas?

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  • Help understanding the Single Responsibility Principle

    - by user204588
    I'm trying to understand what a responsibility actually is so I want to use an example of something I'm currently working on. I have a app that imports product information from one system to another system. The user of the apps gets to choose various settings for which product fields in one system that want to use in the other system. So I have a class, say ProductImporter and it's responsibility is to import products. This class is large, probably too large. The methods in this class are complex and would be for example, getDescription. This method doesn't simply grab a description from the other system but sets a product description based on various settings set by the user. If I were to add a setting and a new way to get a description, this class could change. So, is that two responsibilities? Is there one that imports products and one that gets a description. It would seem this way, almost every method I have would be in it's own class and that seems like overkill. I really need a good description of this principle because it's hard for me to completely understand. I don't want needless complexity.

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  • Is there a standard lexer/parser tool for Python?

    - by Salim Fadhley
    A volunteer job requires us to convert a large number of LaTeX documents into ePub format. It's a series of open-source fiction book which has so far only been produced only on paper via a print on demand service. We'd like to be able to offer the book to users of book-reader devices (such as Kindle) which require the ePub format for best results. Fortunately, ePub is a very simple format, however there's no trivial way for LaTeX to produce the XHTML outut required. We experimented with alternative LaTeX compilers (e.g. plastex) but in the end we figured that it would probably be a lot easier to simply write our own compiler which understands a tiny subset of the LaTeX language and compiles directly to XHTML / ePub. Previously I used a tool on Windows called GOLD. This allowed me to go directly from BNF grammars to a stub parser. It also alllowed me to implement the parser in any language I liked. (I'd choose Python). This product has to work on Linux, so I'm wondering if there's an equivalent toolchain that works as well under Ubutnu / Eclipse / Python. The idea is that we will take the grammar of TeX and just implement a teeny subset of that, but we do not want to spend a huge amount of time worrying about grammar and parsing. A parser generator would obviously save us a great deal of time. Sal UPDATE 1: Bonus marks for a solution with excellent documentation or tutorials.

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  • When does invoking a member function on a null instance result in undefined behavior?

    - by GMan
    This question arose in the comments of a now-deleted answer to this other question. Our question was asked in the comments by STingRaySC as: Where exactly do we invoke UB? Is it calling a member function through an invalid pointer? Or is it calling a member function that accesses member data through an invalid pointer? With the answer deleted I figured we might as well make it it's own question. Consider the following code: #include <iostream> struct foo { void bar(void) { std::cout << "gman was here" << std::endl; } void baz(void) { x = 5; } int x; }; int main(void) { foo* f = 0; f->bar(); // (a) f->baz(); // (b) } We expect (b) to crash, because there is no corresponding member x for the null pointer. In practice, (a) doesn't crash because the this pointer is never used. Because (b) dereferences the this pointer (this->x = 5;), and this is null, the program enters undefined behavior. Does (a) result in undefined behavior? What about if both functions are static?

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  • Pitfalls and practical Use-Cases: Toplink, Hibernate, Eclipse Link, Ibatis ...

    - by Martin K.
    I worked a lot with Hibernate as my JPA implementation. In most cases it works fine! But I have also seen a lot of pitfalls: Remoting with persisted Objects is difficult, because Hibernate replaces the Java collections with its own collection implementation. So the every client must have the Hibernate .jar libraries. You have to take care on LazyLoading exceptions etc. One way to get around this problem is the use of webservices. Dirty checking is done against the Database without any lock. "Delayed SQL", causes that the data access isn't ACID compliant. (Lost data...) Implict Updates So we don't know if an object is modified or not (commit causes updates). Are there similar issues with Toplink, Eclipse Link and Ibatis? When should I use them? Have they a similar performance? Are there reasons to choose Eclipse Link/Toplink... over Hibernate?

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  • "Public" nested classes or not

    - by Frederick
    Suppose I have a class 'Application'. In order to be initialised it takes certain settings in the constructor. Let's also assume that the number of settings is so many that it's compelling to place them in a class of their own. Compare the following two implementations of this scenario. Implementation 1: class Application { Application(ApplicationSettings settings) { //Do initialisation here } } class ApplicationSettings { //Settings related methods and properties here } Implementation 2: class Application { Application(Application.Settings settings) { //Do initialisation here } class Settings { //Settings related methods and properties here } } To me, the second approach is very much preferable. It is more readable because it strongly emphasises the relation between the two classes. When I write code to instantiate Application class anywhere, the second approach is going to look prettier. Now just imagine the Settings class itself in turn had some similarly "related" class and that class in turn did so too. Go only three such levels and the class naming gets out out of hand in the 'non-nested' case. If you nest, however, things still stay elegant. Despite the above, I've read people saying on StackOverflow that nested classes are justified only if they're not visible to the outside world; that is if they are used only for the internal implementation of the containing class. The commonly cited objection is bloating the size of containing class's source file, but partial classes is the perfect solution for that problem. My question is, why are we wary of the "publicly exposed" use of nested classes? Are there any other arguments against such use?

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  • improving data extraction from text file in Java

    - by owca
    I have CSV file with sample data in this form : 220 30 255 0 0 Javascript 200 20 0 255 128 Thinking in java , where the first column is height, second thickness, next three are rgb values for color and last one is title. All need to be treated as separate variables. I have already written my own solution for this, but I'm wondering if there are no better/easier/shorter ways of doing this. Extracted data will then be used to create Book object, throw every Book into array of books and print it with swing. Here's the code : private static Book[] addBook(Book b, Book[] bookTab){ Book[] tmp = bookTab; bookTab = new Book[tmp.length+1]; for(int i = 0; i < tmp.length; i++){ bookTab[i] = tmp[i]; } bookTab[tmp.length] = b; return bookTab; } public static void main(String[] args) { Book[] books = new Book[0]; try { BufferedReader file = new BufferedReader(new FileReader("K:\\books.txt")); String s; while ((s = file.readLine()) != null) { int hei, thick, R, G, B; String tit; hei = Integer.parseInt(s.substring(0, 3).replaceAll(" ", "")); thick = Integer.parseInt(s.substring(4, 6).replaceAll(" ", "")); R = Integer.parseInt(s.substring(10, 13).replaceAll(" ", "")); G = Integer.parseInt(s.substring(14, 17).replaceAll(" ", "")); B = Integer.parseInt(s.substring(18, 21).replaceAll(" ", "")); tit = s.substring(26); System.out.println(tyt+wys+grb+R+G+B); books = addBook(new Book(wys, grb, R, G, B, tyt),books); } file.close(); } catch (IOException e) { //do nothing } }

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  • I cannot grok MVC, what it is, and what it is not?

    - by Hao
    I cannot grok what MVC is, what mindset or programming model should I acquire so MVC stuff can instantly "lightbulb" on my head? If not instantly, what simple programs/projects should I try to do first so I can apply the neat things MVC brings to programming. OOP is intuitive and easier, object is all around us, and the benefits of code reuse using OOP-paradigm instantly click to anyone. You can probably talk to anybody about OOP in a few minutes and lecture some examples and they would get it. While OOP somehow raise the intuitiveness aspect of programming, MVC seems to do the opposite. I'm getting negative thoughts that some future employers(or even clients) would look down upon me for not using MVC technology. Though I probably get the skinnable aspect of MVC, but when I try to apply it to my own project, I don't know where to start. And also some programmers even have diverging views on how to accomplish MVC properly. Take this for instance from Jeff's post about MVC: The view is simply how you lay the data out, how it is displayed. If you want a subset of some data, for example, my opinion is that is a responsibility of the model. So maybe some programmers use MVC, but they somehow inadvertently use the View or the Controller to extract a subset of data. Why we can't have a definitive definition of what and how to accomplish MVC properly? And also, when I search for MVC .NET programs, most of it applies to web programs, not desktop apps, this intrigue me further. My guess is, this is most advantageous to web apps, there's not much problem about intermixed view(html) and controller(program code) in desktop apps.

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  • How to refactor use of the general Exception?

    - by Colin
    Our code catches the general exception everywhere. Usually it writes the error to a log table in the database and shows a MessageBox to the user to say that the operation requested failed. If there is database interaction, the transaction is rolled back. I have introduced a business logic layer and a data access layer to unravel some of the logic. In the data access layer, I have chosen not to catch anything and I also throw ArgumentNullExceptions and ArgumentOutOfRangeExceptions so that the message passed up the stack does not come straight from the database. In the business logic layer I put a try catch. In the catch I rollback the transaction, do the logging and rethrow. In the presentation layer there is another try catch that displays a MessageBox. I am now thinking about catching a DataException and an ArgumentException instead of an Exception where I know the code only accesses a database. Where the code accesses a web service, then I thought I would create my own "WebServiceException", which would be created in the data access layer whenever an HttpException, WebException or SoapException is thrown. So now, generally I will be catching 2 or 3 exceptions where currently I catch just the general Exception, and I think that seems OK to me. Does anyone wrap exceptions up again to carry the message up to the presentation layer? I think I should probably add a try catch to Main() that catches Exception, attempts to log it, displays an "Application has encountered an error" message and exits the application. So, my question is, does anyone see any holes in my plan? Are there any obvious exceptions that I should be catching or do these ones pretty much cover it (other than file access - I think there is only 1 place where we read-write to a config file).

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  • How to implement or emulate an "abstract" OCUnit test class?

    - by Quinn Taylor
    I have a number of Objective-C classes organized in an inheritance hierarchy. They all share a common parent which implements all the behaviors shared among the children. Each child class defines a few methods that make it work, and the parent class raises an exception for the methods designed to be implemented/overridden by its children. This effectively makes the parent a pseudo-abstract class (since it's useless on its own) even though Objective-C doesn't explicitly support abstract classes. The crux of this problem is that I'm unit testing this class hierarchy using OCUnit, and the tests are structured similarly: one test class that exercises the common behavior, with a subclass corresponding to each of the child classes under test. However, running the test cases on the (effectively abstract) parent class is problematic, since the unit tests will fail in spectacular fashion without the key methods. (The alternative of repeating the common tests across 5 test classes is not really an acceptable option.) The non-ideal solution I've been using is to check (in each test method) whether the instance is the parent test class, and bail out if it is. This leads to repeated code in every test method, a problem that becomes increasingly annoying if one's unit tests are highly granular. In addition, all such tests are still executed and reported as successes, skewing the number of meaningful tests that were actually run. What I'd prefer is a way to signal to OCUnit "Don't run any tests in this class, only run them in its child classes." To my knowledge, there isn't (yet) a way to do that, something similar to a +(BOOL)isAbstractTest method I can implement/override. Any ideas on a better way to solve this problem with minimal repetition? Does OCUnit have any ability to flag a test class in this way, or is it time to file a Radar? Edit: Here's a link to the test code in question. Notice the frequent repetition of if (...) return; to start a method, including use of the NonConcreteClass() macro for brevity.

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