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  • How to iterate JPA collections in Google App engine

    - by palto
    Hi I use Google App Engine with datanucleus and JPA. I'm having a real hard time grasping how I'm supposed to read stuff from data store and pass it to JSP. If I load a list of POJOs with entitymanager and pass it to JSP, it crashes to org.datanucleus.exceptions.NucleusUserException: Object Manager has been closed. I understand why this is happening. Obviously because I fetch the list, close the entity manager and pass it to JSP, at which point it will fail because the list is lazy. How do I make the list NOT lazy without resorting to hacks like calling size() or something like that? Here is what I'm trying to do: @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { req.setAttribute("parties", getParties()); RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/WEB-INF/parties.jsp"); dispatcher.forward(req, resp); } private List<Party> getParties(){ EntityManager em = entityManagerProvider.get(); try{ Query query = em.createQuery("SELECT p FROM Party p"); return query.getResultList(); }finally{ em.close(); } }

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  • Telerik chart not loading correctly in new window (ajax issue?)

    - by Phillip Schmidt
    I have a page which contains user controls with Telerik Charts (grids also, but they work fine). From this page, the user can click on a button to be redirected to a "Printer-Friendly Version" type page, which opens a new window via javascript and goes through a slightly different view (for formatting and stuff), but the telerik code is all the same. The problem is, my Chart displays just fine in the original window, but the new window displays basically an empty chart with no data. This bug is only present in IE, and only applies to Charts. Grids work fine, for whatever reason. I'm thinking this is due to differences in script caching between browsers -- correct me if I'm wrong, I'm semi-new to client-directed web development. Anyway I read somewhere that Telerik has issues with loading data and/or js files when loaded via ajax, so maybe that's the problem? If so, how could I get around this? And if not, any ideas on what could be causing this issue? It's causing me a great deal of frustration, since a print preview page seems like it should be the easiest of jobs. Edit: The charts are being rendered as html (if somebody can explain how to render them as images, that would be awesome). And dev tools shows basically the same thing between chrome and IE. Whenever my web service goes back up ill WinMerge them and look for any peculiarities/differences between them. In the mean time, though, the "render as an image" concept sounds promising. That way I could just save the image from the first page, and insert it right into the print preview page, right?. And since it's a print-preview page, it's not going to need to be interactive or anything, so that'd work out nicely. Another (important) Edit: These are probably the culprit... And here is a little more detail on that: And here is a side-by-side of it working(in chrome) and not working (in IE):

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  • Should I pass a SqlDataReader by reference or not when passing it out to multiple threads.

    - by deroby
    Hi all, being new to c# I've run into this 'conundrum' when passing around a SqlDataReader between different threads. Without going into too much detail, the idea is to have a main thread fetching data from the database (a large recordset) and then have a helper-task run through this record by record and doing some stuff based upon the contents of this. There is no feedback to the recordset, it simply wades through until no records are left. This works fine, but given the nature of the job at hand it should be possible to have this job spread over different threads (CPUs) to maximize throughput (the order of execution is of no significance). The question then becomes, when I pass this recordset in a SqlDataReader, do I have to use ref or not ? It kind of boils down to the question : if I pass the object around without specifying ref, won't it create new copies in memory and have records processed n times ? Or, don't I risk having the record-position being moved forward while not all fields have been fully read yet ? The latter seems more like a 'data racing' issue and probably is covered by the lock()ing mechanism (or not?). My initial take on the problem was that it doesn't really hurt passing the variable using ref, yet as a colleague put it : "you only need ref when you're doing something wrong" =) Additionally using ref restricts me from applying a Using() construction too which isn't very nice either. I thus create a "basic" project that tackles the same approach but without the ref notation. Tests so far show that it works flawlessly on a Core2Duo (2cpu) using any number of threads, yet I'm still a bit wary... What do you experts think about this ? Use ref or not ? You can find the test-project here as it seems I can't upload it to this question directly ?!? ps: it's just a test-project and I'm new to c#, so please be gentle on me when breaking down the code =P

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  • Ajax Request using jQuery in Rails

    - by Steve
    Hi... I am sending an Ajax Request using jQuery. What happens is that I am getting an "405 Method Not Allowed" Error. I am just posting a form, which would get the detail from the form and insert it into the DB. Just the usual stuff.I am using WEBrick that comes as default with the rails package. Can somebody please tell me how to fix this. This is the code that triggers the Ajax Request $.post($(this).attr("action") + ".js",$(this).serialize(),null,"script"); Response Headers Cache-Control no-cache Allow GET, PUT, DELETE Content-Type text/html; charset=utf-8 Content-Length 9502 Server WEBrick/1.3.1 (Ruby/1.9.1/2009-12-07) Date Wed, 02 Jun 2010 20:41:33 GMT Connection Keep-Alive Request Headers Host localhost:3000 User-Agent Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.3) Gecko/20100401 Firefox/3.6.3 Accept application/json, text/javascript, */* Accept-Language en-us,en;q=0.5 Accept-Encoding gzip,deflate Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive 115 Connection keep-alive Content-Type application/x-www-form-urlencoded; charset=UTF-8 X-Requested-With XMLHttpRequest Referer http://localhost:3000/viewspot/3 Content-Length 141 Pragma no-cache Cache-Control no-cache

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  • How does one gets started with Winforms style applications on Win32?

    - by Billy ONeal
    EDIT: I'm extremely tired and frustrated at the moment -- please ignore that bit in this question -- I'll edit it in the morning to be better. Okay -- a bit of background: I'm a C++ programmer mostly, but the only GUI stuff I've ever done was on top of .NET's WinForms platform. I'm completely new to Windows GUI programming, and despite Petzold's excellent book, I'm extremely confused. Namely, it seems that most every reference on getting started with Win32 is all about drawing lines and curves and things -- a topic about which (at least at present time) I couldn't care less. I need a checked list box, a splitter, and a textbox -- something that would take less than 10 minutes to do in Winforms land. It has been recommended to me to use the WTL library, which provides an implementation of all three of these controls -- but I keep getting hung up on simple things, such as getting the damn controls to use the right font, and getting High DPI working correctly. I've spent two freaking days on this, and I can't help but think there has to be a better reference for these kinds of things than I've been able to find. Petzold's book is good, but it hasn't been updated since Windows 95 days, and there's been a LOT changed w.r.t. how applications should be correctly developed since it was published. I guess what I'm looking for is a modern Petzold book. Where can I find such a resource, if any?

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  • C++ Namespaces & templates question

    - by Kotti
    Hi! I have some functions that can be grouped together, but don't belong to some object / entity and therefore can't be treated as methods. So, basically in this situation I would create a new namespace and put the definitions in a header file, the implementation in cpp file. Also (if needed) I would create an anonymous namespace in that cpp file and put all additional functions that don't have to be exposed / included to my namespace's interface there. See the code below (probably not the best example and could be done better with another program architecture, but I just can't think of a better sample...) Sample code (header) namespace algorithm { void HandleCollision(Object* object1, Object* object2); } Sample code (cpp) #include "header" // Anonymous namespace that wraps // routines that are used inside 'algorithm' methods // but don't have to be exposed namespace { void RefractObject(Object* object1) { // Do something with that object // (...) } } namespace algorithm { void HandleCollision(Object* object1, Object* object2) { if (...) RefractObject(object1); } } So far so good. I guess this is a good way to manage my code, but I don't know what should I do if I have some template-based functions and want to do basically the same. If I'm using templates, I have to put all my code in the header file. Ok, but how should I conceal some implementation details then? Like, I want to hide RefractObject function from my interface, but I can't simply remove it's declaration (just because I have all my code in a header file)... The only approach I came up with was something like: Sample code (header) namespace algorithm { // Is still exposed as a part of interface! namespace impl { template <typename T> void RefractObject(T* object1) { // Do something with that object // (...) } } template <typename T, typename Y> void HandleCollision(T* object1, Y* object2) { impl::RefractObject(object1); // Another stuff } } Any ideas how to make this better in terms of code designing?

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  • Why doesn't this external JavaScript load?

    - by Ben Herila
    I've been futzing with this for hours trying to figure out why codemirror.js won't load in any browser other than Firefox. Any ideas? index.html <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <title></title> <script src="CodeMirror/js/codemirror.js"></script> <link href="Styles/Style.css" rel="stylesheet" type="text/css" /> <link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="stylesheet" type="text/css" /> <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script> <script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js"></script> <script type="text/javascript"> $(document).ready(function () { $('#container-1').tabs(); }); </script> <style type="text/css"> /* (some css) */ </style> </head><body> <!-- (some stuff) --> </body></html> CodeMirror/js/codemirror.js alert("LOL");

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  • Ruby on Rails user login form in main layout

    - by Jimmy
    Hey guys I have a simple ror application for some demo stuff. I am running into a problem with trying to move my login form from the users controller and just have it displayed in the main navigation so that a user can easily log in from anywhere. The problem is the form doesn't generate the correct action for the html form. Ruby code: <% form_for(url_for(:action => 'login'), :method => 'post') do |f| %> <li><%= f.text_field("username") %></li> <li><%= f.password_field("password") %></li> <li><%= submit_tag("Login")%></li> <% end %> The problem is depending on the controller I am currently in this generates HTML actions like <form action="/home" method="post">...</form> when it should be generating HTML like so <form action="/login" method="post">...</form> I know I could simply do an HTML form here but I want to keep things as easy to maintain as possible. Any help?

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  • Why does GLSL's arithmetic functions yield so different results on the iPad than on the simulator?

    - by cheeesus
    I'm currently chasing some bugs in my OpenGL ES 2.0 fragment shader code which is running on iOS devices. The code runs fine in the simulator, but on the iPad it has huge problems and some of the calculations yield vastly different results, I had for example 0.0 on the iPad and 4013.17 on the simulator, so I'm not talking about small differences which could be the result of some rounding errors. One of the things I noticed is that, on the iPad, float1 = pow(float2, 2.0); can yield results which are very different from the results of float1 = float2 * float2; Specifically, when using pow(x, 2.0) on a variable containing a larger negative number like -8, it seemed to return a value which satified the condition if (powResult <= 0.0). Also, the result of both operations (pow(x, 2.0) as well as x*x) yields different results in the simulator than on the iPad. Used floats are mediump, but I get the same stuff with highp. Is there a simple explanation for those differences? I'm narrowing the problem down, but it takes so much time, so maybe someone can help me here with a simple explanation.

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  • Can I architect a web app so it can be deployed to either the cloud or a dedicated server / VPS ? Ho

    - by CAD bloke
    Is there are an architecture versatile enough that it may be deployed to either a cloud server or to a dedicated (or VPS) server with minimal change? Obviously there would be config changes but I'd rather leave the rest of the app consistent, keeping one maintainable codebase. The app would be ASP.NET &/or ASP.MVC. My dev environment is VS 2010. The cloud may, or may not be, Azure. Dedicated or VPS would be Win Server 2008. Probably. It is not a public-facing web site. The web app I have in mind would be a separate deployment for each client. Some clients would be small-scale, some will prefer the app to run on a local intranet rather than on the web. Other clients may prefer the cloud approach for a black-box solution. The app may run for a few hours or it may run indefinitely, it depends on the client and the project. Other than deployment scenarios the apps would be more or less identical. As you may see from the tags, I'm assuming a message-based architecture is probably the most versatile but I'm also used to being wrong about this stuff. All suggestions and pointers welcome regarding general architectures and also specific solutions.

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  • Using FOR XML AUTO against a synonym

    - by Rick
    We've just switched to synonyms for linked server stuff, and noticed that our FOR XML output is no longer correct. When returning XML results from a view, we could alias the view and that would be assigned as the element name. With synonyms, however, it seems to ignore the alias? We're still mostly on SQL 2005 - this bug doesn't seem to happen on our 2008 instance. Is this a known problem, and any ideas for work-arounds? For example, this is what we used to be able to do: select top 3 number from Numbers as elementname for xml auto <elementname number="0"/><elementname number="1"/><elementname number="2"/> And this is what happens with a synonym: select top 3 number from Numbers_synonym as elementname for xml auto <dbo.Numbers number="0"/><dbo.Numbers number="1"/><dbo.Numbers number="2"/> As you can see, SQL Server seems to use the name of the actual referenced object instead of the alias. This gets worse for cross server queries, because you get the four-part name instead of the nice alias. (eg: <rick_server.rick_database.dbo.Numbers number="0"/>...)

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  • How to design authentication in a thick client, to be fail safe?

    - by Jay
    Here's a use case: I have a desktop application (built using Eclipse RCP) which on start, pops open a dialog box with 'UserName' and 'Password' fields in it. Once the end user, inputs his UserName and Password, a server is contacted (a spring remote-servlet, with the client side being a spring httpclient: similar to the approaches here.), and authentication is performed on the server side. A few questions related to the above mentioned scenario: If said this authentication service were to go down, what would be the best way to handle further proceedings? Authentication is something that I cannot do away with. Would running the desktop client in a "limited" mode be a good idea? For instance, important features/menus/views will be disabled, rest of the application will be accessible? Should I have a back up authentication service running on a different machine, working as a backup? What are the general best-practices in this scenario? I remember reading about google gears and how it would let you edit and do stuff offline - should something like this be designed? Please let me know your design/architectural comments/suggestions. Appreciate your help.

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  • SQL Aggregate all Purchases for a certain product with same rebatecode

    - by debuggerlikeanother
    Hi SO, i would like to aggregate all purchases for a certain product that used the same rebatecode (using SQL Server 2005) Assume we have the following table: ID ProductID Product RebateCode Amount 1 123 7HM ABC 1 2 123 7HM XYZ 2 3 124 7HM ABC 10 4 124 7HM XYZ 20 5 125 2EB LOI 4 6 126 2EB LOI 40 CREATE TABLE #ProductSales(ID SMALLINT, ProductID int, Product varchar(6), RebateCode varchar(4), Amount int) GO INSERT INTO #ProductSales select 1, 123, '7HM', 'A', 1 union all select 2, 123, '7HM', 'B', 2 union all select 3, 124, '7HM', 'A', 10 union all select 4, 124, '7HM', 'B', 20 union all select 5, 125, '7HM', 'A', 100 union all select 6, 125, '7HM', 'B', 200 union all select 7, 125, '7HM', 'C', 3 union all select 8, 126, '2EA', 'E', 4 union all select 8, 127, '2EA', 'E', 40 union all select 9, 128, '2EB', 'F', 5 union all select 9, 129, '2EB', 'F', 50 union all select 10, 130, '2EB', 'F', 500 GO SELECT * FROM #ProductSales GO /* And i would like to have the following result Product nrOfProducts CombinationRebateCode SumAmount ABC LOI XYZ 7HM 2 ABC, XYZ 33 11 0 22 2EB 2 LOI 44 0 44 0 .. */ CREATE TABLE #ProductRebateCode(Product varchar(6), nrOfProducts int, sumAmountRebateCombo int, rebateCodeCombination varchar(80), A int, B int, C int, E int, F int) Go INSERT INTO #ProductRebateCode select '7HM', 2, 33, 'A, B', 2, 2, 0, 0, 0 union all select '7HM', 1, 303, 'A, B, C', 1, 1, 1, 0, 0 union all select '2EA', 2, 44, 'E', 0, 0, 0, 2, 0 union all select '2EB', 3, 555, 'E', 0, 0, 0, 0, 2 Select * from #ProductRebateCode -- Drop Table #ProductSales IF EXISTS ( SELECT * FROM tempdb.dbo.sysobjects WHERE name LIKE '#ProductSales%') DROP TABLE #ProductSales -- Drop Table #ProductRebateCode IF EXISTS ( SELECT * FROM tempdb.dbo.sysobjects WHERE name LIKE '#ProductRebateCode%') DROP TABLE #ProductRebateCode I would like to have the result like in the example (see second select (#ProductRebateCode). I tried to achieve it with the crosstab from this post: http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=6216&whichpage=6. exec CrossTab2b @SQL = 'SELECT [ProductID], Product, RebateCode, Amount FROM #ProductSales' ,@PivotCol = 'RebateCode' ,@Summaries = 'Sum(Amount ELSE 0)[_Sum], Count([ProductID])[_nrOfProducts]' /* SUM(Amount ELSE 0)[Amount], COUNT(Amount)[Qty] */ ,@GroupBy = 'RebateCode, Product' ,@OtherFields = 'Product' I believe that this could work, but i am unable to solve it. Do you believe that it is possible to achieve what i am trying without MDX or the other fancy ?DX-Stuff? Best regards And Thanks a lot debugger the other

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  • Plotting a graph with GD

    - by Nayena
    Here it goes. I have been thinking about this for a long time, and havent really been able to put up a proper way to do it yet. I havent implemented anything yet, as im still designing the thing. The idea is that i crawl a website for internal links, i got this settled, its easy, but after the crawling, i end up with an array with lots of links, and how many times those particular link appears on the site that i crawled (and how they're connected). With this huge array, i want to draw a graph somehow. Assuming i can handle the data correctly, the real question here is how i can draw this in a image by the use of the GD library. I figured if theres less than 12 elements, i can align them up on a unit circle spacing them up as a circle and then connecting them accordingly, so anything up to 12 elements shouldn't be a problem, but if theres more than 12, it could be awesome getting them lined up like this Or well, thats just a rough drawing, but i guess its just to prove a point. So i'm here looking for guidance or tips towards getting the math down to getting the stuff lined up in a good way. I have previously made bar-graphs, so i have little experience doing math with GD. If possible, id prefer not using some plotter-library - in the end, it gives me a better understanding on how things are supposed to be.

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  • Access property of DataContext in ItemTemplate

    - by amrinder
    My datacontext has two properties: Items which is a collection and DetailsVisiblity which is enum of type Visiblity. On the page I have a Listbox with ItemsSource="{Binding Entries}". Inside the DataTemplate, I can bind stuff to properties of Items, but how do I get access to DetailsVisiblity which is a property of DataContext? DataContext has two properties: ObservableCollection<Item> Entries, and Visibility DetailsVisiblity. Item class has two properties: Title and Details. Here is the view. How do I bind Visiblity of the second TextBlock to DetailsVisiblity property? <ListBox "{Binding Items}"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel> <TextBlock Text="{Binding Title}" /> <TextBlock Text="{Binding Details}" Visibility="{Binding ???}" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox>

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  • Have you dealt with space hardening?

    - by Tim Post
    I am very eager to study best practices when it comes to space hardening. For instance, I've read (though I can't find the article any longer) that some core parts of the Mars rovers did not use dynamic memory allocation, in fact it was forbidden. I've also read that old fashioned core memory may be preferable in space. I was looking at some of the projects associated with the Google Lunar Challenge and wondering what it would feel like to get code on the moon, or even just into space. I know that space hardened boards offer some sanity in such a harsh environment, however I'm wondering (as a C programmer) how I would need to adjust my thinking and code if I was writing something that would run in space? I think the next few years might show more growth in private space companies, I'd really like to at least be somewhat knowledgeable regarding best practices. Can anyone recommend some books, offer links to papers on the topic or (gasp) even a simulator that shows you what happens to a program if radiation, cold or heat bombards a board that sustained damage to its insulation? I think the goal is keeping humans inside of a space craft (as far as fixing or swapping stuff) and avoiding missions to fix things. Furthermore, if the board maintains some critical system, early warnings seem paramount.

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  • Dynamic editor upload into web page. Need advice

    - by Andrew Florko
    Hello everybody, I am writing intranet site for tracking employees science activities in organization. There lots of editable information on each personal page (science degree, publications & so on) so I upload editor per request (user clicks "edit" and modal dialog with html editor: set of textboxes/comboboxes/autocomplete features & validation logic appears). Editor is html layout that is wrapped with jquery dialog plugin + some logic, written as javascript functions that should be invoked from the callee page (onsubmit, validate, afterLoad editor events). There are also attributes (editor preferrable with and height) that are passed to callee page also. Currently I send these functions & attribute as ... function onsubmit() { }; function validate() { } var width = 640; var height = 800 ... code that is embedded into the request page. Function calls and editor markup wrap with jquery plugin completed in the callee page. It works, but I have some try { call editor event handler } catch { } stuff in callee page (because not every editor provides these functions) and some attributes (editor width & height for instance) that are loaded as variables declared in javascript. Please, suggest, is there a better approach to build & use custom editors for my situation. Thank you in advance!

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  • Imlpementations of an Interface with Different Types?

    - by b3njamin
    Searched as best I could but unfortunately I've learned nothing relevant; basically I'm trying to work around the following problem in C#... For example, I have three possible references (refA, refB, refC) and I need to load the correct one depending on a configuration option. So far however I can't see a way of doing it that doesn't require me to use the name of said referenced object all through the code (the referenced objects are provided, I can't change them). Hope the following code makes more sense: public ??? LoadedClass; public Init() { /* load the object, according to which version we need... */ if (Config.Version == "refA") { Namespace.refA LoadedClass = new refA(); } else if (Config.Version == "refB") { Namespace.refB LoadedClass = new refB(); } else if (Config.Version == "refC") { Namespace.refC LoadedClass = new refC(); } Run(); } private void Run(){ { LoadedClass.SomeProperty... LoadedClass.SomeMethod(){ etc... } } As you can see, I need the Loaded class to be public, so in my limited way I'm trying to change the type 'dynamically' as I load in which real class I want. Each of refA, refB and refC will implement the same properties and methods but with different names. Again, this is what I'm working with, not by my design. All that said, I tried to get my head around Interfaces (which sound like they're what I'm after) but I'm looking at them and seeing strict types - which makes sense to me, even if it's not useful to me. Any and all ideas and opinions are welcome and I'll clarify anything if necessary. Excuse any silly mistakes I've made in the terminology, I'm learning all this for the first time. I'm really enjoying working with an OOP language so far though - coming from PHP this stuff is blowing my mind :-)

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  • Java website protection solutions (especially XSS)

    - by Mark
    I'm developing a web application, and facing some security problems. In my app users can send messages and see other's (a bulletin board like app). I'm validating all the form fields that users can send to my app. There are some very easy fields, like "nick name", that can be 6-10 alpabetical characters, or message sending time, which is sended to the users as a string, and then (when users ask for messages, that are "younger" or "older" than a date) I parse this with SimpleDateFormat (I'm developing in java, but my question is not related to only java). The big problem is the message field. I can't restrict it to only alphabetical characters (upper or lowercase), because I have to deal with some often use characters like ",',/,{,} etc... (users would not be satisfied if the system didn't allow them to use these stuff) According to this http://ha.ckers.org/xss.html, there are a lot of ways people can "hack" my site. But I'm wondering, is there any way I can do to prevent that? Not all, because there is no 100% protection, but I'd like a solution that can protect my site. I'm using servlets on the server side, and jQuery, on the client side. My app is "full" AJAX, so users open 1 JSP, then all the data is downloaded and rendered by jQuery using JSON. (yeah, I know it's not "users-without-javascript" friendly, but it's 2010, right? :-) ) I know front end validation is not enough. I'd like to use 3 layer validation: - 1. front end, javascript validate the data, then send to the server - 2. server side, the same validation, if there is anything, that shouldn't be there (because of client side javascript), I BAN the user - 3. if there is anything that I wasn't able to catch earlier, the rendering process handle and render appropriately Is there any "out of the box" solution, especially for java? Or other solution that I can use?

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  • Calling private constructors with Reflection.Emit?

    - by Jakob Botsch Nielsen
    I'm trying to emit the following IL: LocalBuilder pointer = il.DeclareLocal(typeof(IntPtr)); il.Emit(OpCodes.Ldarg_0); il.Emit(OpCodes.Stloc, pointer); il.Emit(OpCodes.Ldloca, pointer); il.Emit(OpCodes.Call, typeof(IntPtr).GetMethod("ToPointer")); il.Emit(OpCodes.Ret); The delegate I bind with has the signature void* TestDelegate(IntPtr ptr) It throws the exception Operation could destabilize the runtime. Anyone knows what's wrong? EDIT: Alright, so I got the IL working now. The entire goal of this was to be able to call a private constructor. The private constructor takes a pointer so I can't use normal reflection. Now.. When I call it, I get an exception saying Attempt by method <built method> to access method <private constructor> failed. Apparently it's performing security checks - but from experience I know that Reflection is able to do private stuff like this normally, so hopefully there is a way to disable that check?

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  • Using EhCache for session.createCriteria(...).list()

    - by James Smith
    I'm benchmarking the performance gains from using a 2nd level cache in Hibernate (enabling EhCache), but it doesn't seem to improve performance. In fact, the time to perform the query slightly increases. The query is: session.createCriteria(MyEntity.class).list(); The entity is: @Entity @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE) public class MyEntity { @Id @GeneratedValue private long id; @Column(length=5000) private String data; //---SNIP getters and setters--- } My hibernate.cfg.xml is: <!-- all the normal stuff to get it to connect & map the entities plus:--> <property name="hibernate.cache.region.factory_class"> net.sf.ehcache.hibernate.EhCacheRegionFactory </property> The MyEntity table contains about 2000 rows. The problem is that before adding in the cache, the query above to list all entities took an average of 65 ms. After the cache, they take an average of 74 ms. Is there something I'm missing? Is there something extra that needs to be done that will increase performance?

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  • How to limit setAccessible to only "legitimate" uses?

    - by polygenelubricants
    The more I learned about the power of setAccessible, the more astonished I am at what it can do. This is adapted from my answer to the question (Using reflection to change static final File.separatorChar for unit testing). import java.lang.reflect.*; public class EverythingIsTrue { static void setFinalStatic(Field field, Object newValue) throws Exception { field.setAccessible(true); Field modifiersField = Field.class.getDeclaredField("modifiers"); modifiersField.setAccessible(true); modifiersField.setInt(field, field.getModifiers() & ~Modifier.FINAL); field.set(null, newValue); } public static void main(String args[]) throws Exception { setFinalStatic(Boolean.class.getField("FALSE"), true); System.out.format("Everything is %s", false); // "Everything is true" } } You can do truly outrageous stuff: public class UltimateAnswerToEverything { static Integer[] ultimateAnswer() { Integer[] ret = new Integer[256]; java.util.Arrays.fill(ret, 42); return ret; } public static void main(String args[]) throws Exception { EverythingIsTrue.setFinalStatic( Class.forName("java.lang.Integer$IntegerCache") .getDeclaredField("cache"), ultimateAnswer() ); System.out.format("6 * 9 = %d", 6 * 9); // "6 * 9 = 42" } } Presumably the API designers realize how abusable setAccessible can be, but must have conceded that it has legitimate uses to provide it. So my questions are: What are the truly legitimate uses for setAccessible? Could Java has been designed as to NOT have this need in the first place? What would the negative consequences (if any) of such design be? Can you restrict setAccessible to legitimate uses only? Is it only through SecurityManager? How does it work? Whitelist/blacklist, granularity, etc? Is it common to have to configure it in your applications?

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  • is concatenating the only way to 'import' one JS lib from another?

    - by Nikita
    Disclaimer: JS novice I have a JS widget that depends on JQuery. The widget's going to be embedded in a 3rd party site but I figure out how to avoid declaring dependency on jquery on the widget-hosting page: 3rd party's page: <head> <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.js"></script> <script type="text/javascript" src="http://mydomain/mywidget.js"></script> </head> mywidget.js jQuery(document).ready(function() { //do stuff }); I'd rather not include jquery.js in the 3d party page but express the dependency inside mywidget.js (so i can change this dependency or add/remove others w/o having to update the widget-hosting page) I tried adding: var script = document.createElement('script'); script.src = 'http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.js'; script.type = 'text/javascript'; document.getElementsByTagName('head')[0].appendChild(script); to the top of mywidget.js but that didn't work - jquery.js did load on page load but "jQuery" was not recognized. What did work was concatenating jquery.js and mywidget.js into a single .js file. But that seems kind of lame - is there no equivalent to? import com.jquery.*; thanks!

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  • How can I merge two Linq IEnumerable<T> queries without running them?

    - by makerofthings7
    How do I merge a List<T> of TPL-based tasks for later execution? public async IEnumerable<Task<string>> CreateTasks(){ /* stuff*/ } My assumption is .Concat() but that doesn't seem to work: void MainTestApp() // Full sample available upon request. { List<string> nothingList = new List<string>(); nothingList.Add("whatever"); cts = new CancellationTokenSource(); delayedExecution = from str in nothingList select AccessTheWebAsync("", cts.Token); delayedExecution2 = from str in nothingList select AccessTheWebAsync("1", cts.Token); delayedExecution = delayedExecution.Concat(delayedExecution2); } /// SNIP async Task AccessTheWebAsync(string nothing, CancellationToken ct) { // return a Task } I want to make sure that this won't spawn any task or evaluate anything. In fact, I suppose I'm asking "what logically executes an IQueryable to something that returns data"? Background Since I'm doing recursion and I don't want to execute this until the correct time, what is the correct way to merge the results if called multiple times? If it matters I'm thinking of running this command to launch all the tasks var AllRunningDataTasks = results.ToList(); followed by this code: while (AllRunningDataTasks.Count > 0) { // Identify the first task that completes. Task<TableResult> firstFinishedTask = await Task.WhenAny(AllRunningDataTasks); // ***Remove the selected task from the list so that you don't // process it more than once. AllRunningDataTasks.Remove(firstFinishedTask); // TODO: Await the completed task. var taskOfTableResult = await firstFinishedTask; // Todo: (doen't work) TrustState thisState = (TrustState)firstFinishedTask.AsyncState; // TODO: Update the concurrent dictionary with data // thisState.QueryStartPoint + thisState.ThingToSearchFor Interlocked.Decrement(ref thisState.RunningDirectQueries); Interlocked.Increment(ref thisState.CompletedDirectQueries); if (thisState.RunningDirectQueries == 0) { thisState.TimeCompleted = DateTime.UtcNow; } }

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  • Database class is not correctly connecting to my database.

    - by blerh
    I'm just venturing into the world of OOP so forgive me if this is a n00bish question. This is what I have on index.php: $dbObj = new Database(); $rsObj = new RS($dbObj); This is the Database class: class Database { private $dbHost; private $dbUser; private $dbPasswd; private $dbName; private $sqlCount; function __construct() { $this->dbHost = 'localhost'; $this->dbUser = 'root'; $this->dbPasswd = ''; $this->dbName = 'whatever'; $this->sqlCount = 0; } function connect() { $this->link = mysql_connect($this->db_host, $this->db_user, $this->db_passwd); if(!$this->link) $this->error(mysql_error()); $this->selection = mysql_select_db($this->db_name, $this->link); if(!$this->selection) $this->error(mysql_error()); } } I've shortened it to just the connect() method to simplify things. This is the RS class: class RS { private $username; private $password; function __construct($dbObj) { // We need to get an account from the db $dbObj->connect(); } } As you can probably see, I need to access and use the database class in my RS class. But I get this error when I load the page: Warning: mysql_connect() [function.mysql-connect]: Access denied for user 'ODBC'@'localhost' (using password: NO) in C:\xampp\htdocs\includes\database.class.php on line 22 The thing is I have NO idea where it got the idea that it needs to use ODBC as a user... I've read up on doing this stuff and from what I can gather I am doing it correctly. Could anyone lend me a hand? Thank you.

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