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• What AOP tools exist for doing aspect-oriented programming at the assembly language level against x8

  - by JohnnySoftware

  Looking for a tool I can use to do aspect-oriented programming at the assembly language level. For experimentation purposes, I would like the code weaver to operate native application level executable and dynamic link libraries. I have already done object-oriented AOP. I know assembly language for x86 and so forth. I would like to be able to do logging and other sorts of things using the familiar before/after/around constructs. I would like to be able to specify certain instructions or sequences/patterns of consecutive instructions as what to do a pointcut on since assembly/machine language is not exactly the most semantically rich computer language on the planet. If debugger and linker symbols are available, naturally, I would like to be able to use them to identify subroutines' entry points , branch/call/jump target addresses, symbolic data addresses, etc. I would like the ability to send notifications out to other diagnostic tools. Thus, support for sending data through connection-oriented sockets and datagrams is highly desirable. So is normal logging to files, UI, etc. This can be done using the action part of an aspect to make a function call, but then there are portability issues so the tool needs to support a flexible, well-abstracted logging/notifying mechanism with a clean, simple yet flexible. The goal is rapid-QA. The idea is to be able to share aspect source code braodly within communties as well as publicly. So, there needs to be a declarative security policy file that users can share. This insures that nothing untoward that is hidden directly or indirectly in an aspect source file slips by the execution manager. The policy file format needs to be simple to read, write, modify, understand, type-in, edit, and generate. Sort of like Java .policy files. Think the exact opposite of anything resembling XML Schema files and you get the idea. Is there such a tool in existence already?

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• Why does VBA Find loop fail when called from Evaluate?

  - by Abiel

  I am having some problems running a find loop inside of a subroutine when the routine is called using the Application.Evaluate or ActiveSheet.Evaluate method. For example, in the code below, I define a subroutine FindSub() which searches the sheet for a string "xxx". The routine CallSub() calls the FindSub() routine using both a standard Call statement and Evaluate. When I run Call FindSub, everything will work as expected: each matching address gets printed out to the immediate window and we get a final message "Finished up" when the code is done. However, when I do Application.Evaluate "FindSub()", only the address of the first match gets printed out, and we never reach the "Finished up" message. In other words, an error is encountered after the Cells.FindNext line as the loop tries to evaluate whether it should continue, and program execution stops without any runtime error being printed. I would expect both Call FindSub and Application.Evaluate "FindSub()" to yield the same results in this case. Can someone explain why they do not, and if possible, a way to fix this? Thanks. Note: In this example I obviously do not need to use Evaluate. This version is simplified to just focus on the particular problem I am having in a more complex situation. Sub CallSub() Call FindSub Application.Evaluate "FindSub()" End Sub Sub FindSub() Dim rngFoundCell As Range Dim rngFirstCell As Range Set rngFoundCell = Cells.Find(What:="xxx", after:=ActiveCell, LookIn:=xlValues, _ LookAt:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, _ MatchCase:=False, SearchFormat:=False) If Not rngFoundCell Is Nothing Then Set rngFirstCell = rngFoundCell Do Debug.Print rngFoundCell.Address Set rngFoundCell = Cells.FindNext(after:=rngFoundCell) Loop Until (rngFoundCell Is Nothing) Or (rngFoundCell.Address = rngFirstCell.Address) End If Debug.Print "Finished up" End Sub

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• Java Access Token PKCS11 Not found Provider

  - by oracleruiz

  Hello I'm trying to access the keystore from my smartcard in Java. And I'm using the following code.. I'm using the Pkcs11 implementation of OpenSc http://www.opensc-project.org/opensc File windows.cnf = name=dnie library=C:\WINDOWS\system32\opensc-pkcs11.dll Java Code = String configName = "windows.cnf" String PIN = "####"; Provider p = new sun.security.pkcs11.SunPKCS11(configName); Security.addProvider(p); KeyStore keyStore = KeyStore.getInstance("PKCS11", "SunPKCS11-dnie"); =)(= char[] pin = PIN.toCharArray(); keyStore.load(null, pin); When the execution goes by the line with =)(= throws me the following exeption java.security.KeyStoreException: PKCS11 not found at java.security.KeyStore.getInstance(KeyStore.java:635) at ObtenerDatos.LeerDatos(ObtenerDatos.java:52) at ObtenerDatos.obtenerNombre(ObtenerDatos.java:19) at main.main(main.java:27) Caused by: java.security.NoSuchAlgorithmException: no such algorithm: PKCS11 for provider SunPKCS11-dnie at sun.security.jca.GetInstance.getService(GetInstance.java:70) at sun.security.jca.GetInstance.getInstance(GetInstance.java:190) at java.security.Security.getImpl(Security.java:662) at java.security.KeyStore.getInstance(KeyStore.java:632) I think the problem is "SunPKCS11-dnie", but I don't know to put there. I had tried with a lot of combinations... Anyone can help me...

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• What is more viable to use? Javascript libraries or UI Programming tools?

  - by Haresh Karkar

  What is more viable to use:- Javascript Libraries: YUI, jQuery, ExtJs OR UI Programming tools: GWT, ExtGWT, SmartGWT It has become very difficult to choose between them as they are constantly increasing their capabilities to meet newer requirements. We all know the power of jQuery in UI manipulations. The latest news from Microsoft about jQuery being officially part of .Net developr’s toolkit will definitely make jQuery a preferred choice against other JavaScript libraries [See link: http://weblogs.asp.net/scottgu/archive/2008/09/28/jquery-and-microsoft.aspx]. But on the other hand, GWT is building a framework which could be used on client as well as on the sever side. This is definitely going to make developers’ life easy as it does not require developer to be an expert in browser quirks, XMLHttpRequest, and JavaScript in order to develop high-performance web applications. It includes SDK (Java API libraries, compiler, and development server which allows to write client-side applications in Java and deploy them as JavaScript), Speed Tracer and plug-in for Eclipse. GWT is used by many products like Google Wave and AdWords. So question is still un-answered, what is more viable to use? Any thoughts?

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• Can a GeneralPath be modified?

  - by Dov

  java2d is fairly expressive, but requires constructing lots of objects. In contrast, the older API would let you call methods to draw various shapes, but lacks all the new features like transparency, stroke, etc. Java has fairly high costs associated with object creation. For speed, I would like to create a GeneralPath whose structure does not change, but go in and change the x,y points inside. path = new GeneralPath(GeneralPath.WIND_EVEN_ODD, 10); path.moveTo(x,y); path.lineTo(x2, y2); double len = Math.sqrt((x2-x)*(x2-x) + (y2-y)*(y2-y)); double dx = (x-x2) * headLen / len; double dy = (y-y2) * headLen / len; double dx2 = -dy * (headWidth/headLen); double dy2 = dx * (headWidth/headLen); path.lineTo(x2 + dx + dx2, y2 + dy + dy2); path.moveTo(x2 + dx - dx2, y2 + dy - dy2); path.lineTo(x2,y2); This one isn't even that long. Imagine a much longer sequence of commands, and only the ones on the end are changing. I just want to be able to overwrite commands, to have an iterator effectively. Does that exist?

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• Banning by IP with php/mysql

  - by incrediman

  I want to be able to ban users by IP. My idea is to keep a list of IP's as rows in an BannedIPs table (the IP column would be an index). To check users' IP's against the table, I will keep a session variable called $_SESSION['IP'] for each session. If on any request, $_SESSION['IP'] doesn't match $_SERVER['REMOTE_ADDR'], I will update $_SESSION['IP'] and check the BannedIPs table to see if the IP is banned. (A flag will also be saved as a session variable specifying whether or not the user is banned) Here are the things I'm wondering: Does that sound like a good strategy with regards to speed and security (would someone be able to get around the IP ban somehow, other than changing IP's)? What's the best way to structure a mysql query that checks to see if a row exists? That is, what's the best way to query the db to see if a row with a certain IP exists (to check if it's banned)? Should I save the IP's as integers or strings? Note that... I estimate there will be between 1,000-10,000 banned IP's stored in the database. $_SERVER['REMOTE_ADDR'] is the IP from which the current request was sent.

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• How to stop MVC caching the results of invoking and action method?

  - by Trey Carroll

  I am experiencing a problem with IE caching the results of an action method. Other articles I found were related to security and the [Authorize] attribute. This problem has nothing to do with security. This is a very simple "record a vote, grab the average, return the avg and the number of votes" method. The only slightly interesting thing about it is that it is invoked via Ajax and returns a Json object. I believe that it is the Json object that is getting catched. When I run it from FireFox and watch the XHR traffic with Firebug, everything works perfectly. However, under IE 8 the "throbber" graphic doesn't ever have time to show up and the page elements that display the "new" avg and count that are being injected into the page with jQuery are never different. I need a way to tell MVC to never cache this action method. This article seems to address the problem, but I cannot understand it: http://stackoverflow.com/questions/1441467/prevent-caching-of-attributes-in-asp-net-mvc-force-attribute-execution-every-tim I need a bit more context for the solution to understand how to extend AuthorizationAttribute. Please address your answer as if you were speaking to someone who lacks a deep understanding of MVC even if that means replying with an article on some basics/prerequisites that are required. Thanks, Trey Carroll

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• JQuery Cycle fails on Page Refresh

  - by Darknight

  In a similar issue as this one: http://stackoverflow.com/questions/1719475/jquery-cycle-firefox-squishing-images I've managed to overcome the initial problem using Jeffs answer in the above link. However now I have noticed a new bug, upon page refresh it simply does not work. I have tried a hard refresh (ctrl+F5) but this does not work. However when you come page to the page it loads fine. here is my modified version (taken from Jeff's): <script type="text/javascript"> $(document).ready(function() { var imagesRemaining = $('#slideshow img').length; $('#slideshow img').bind('load', function(e) { imagesRemaining = imagesRemaining - 1; if (imagesRemaining == 0) { $('#slideshow').show(); $('#slideshow').cycle({ fx: 'shuffle', speed: 1200 }); } }); }); </script> Any ideas? I've also tried JQuery Live but could not implement it correctly. I've also tried Meta tags to force images to load. But it only works first time round.

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• WF performance with new 20,000 persisted workflow instances each month

  - by Nikola Stjelja

  Windows Workflow Foundation has a problem that is slow when doing WF instances persistace. I'm planning to do a project whose bussiness layer will be based on WF exposed WCF services. The project will have 20,000 new workflow instances created each month, each instance could take up to 2 months to finish. What I was lead to belive that given WF slownes when doing peristance my given problem would be unattainable given performance reasons. I have the following questions: Is this true? Will my performance be crap with that load(given WF persitance speed limitations) How can I solve the problem? We currently have two possible solutions: 1. Each new buisiness process request(e.g. Give me a new drivers license) will be a new WF instance, and the number of persistance operations will be limited by forwarding all status request operations to saved state values in a separate database. 2. Have only a small amount of Workflow Instances up at any give time, without any persistance ofso ever(only in case of system crashes etc.), by breaking each workflow stap in to a separate worklof and that workflow handling each business process request instance in the system that is at that current step(e.g. I'm submitting my driver license reques form, which is step one... we have 100 cases of that, and my step one workflow will handle every case simultaneusly). I'm very insterested in solution for that problem. If you want to discuss that problem pleas be free to mail me at [email protected]

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• Refactoring ADO.NET - SqlTransaction vs. TransactionScope

  - by marc_s

  I have "inherited" a little C# method that creates an ADO.NET SqlCommand object and loops over a list of items to be saved to the database (SQL Server 2005). Right now, the traditional SqlConnection/SqlCommand approach is used, and to make sure everything works, the two steps (delete old entries, then insert new ones) are wrapped into an ADO.NET SqlTransaction. using (SqlConnection _con = new SqlConnection(_connectionString)) { using (SqlTransaction _tran = _con.BeginTransaction()) { try { SqlCommand _deleteOld = new SqlCommand(......., _con); _deleteOld.Transaction = _tran; _deleteOld.Parameters.AddWithValue("@ID", 5); _con.Open(); _deleteOld.ExecuteNonQuery(); SqlCommand _insertCmd = new SqlCommand(......, _con); _insertCmd.Transaction = _tran; // add parameters to _insertCmd foreach (Item item in listOfItem) { _insertCmd.ExecuteNonQuery(); } _tran.Commit(); _con.Close(); } catch (Exception ex) { // log exception _tran.Rollback(); throw; } } } Now, I've been reading a lot about the .NET TransactionScope class lately, and I was wondering, what's the preferred approach here? Would I gain anything (readibility, speed, reliability) by switching to using using (TransactionScope _scope = new TransactionScope()) { using (SqlConnection _con = new SqlConnection(_connectionString)) { .... } _scope.Complete(); } What you would prefer, and why? Marc

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• How to connect a new query script with SSMS add-in?

  - by squillman

  I'm trying to create a SSMS add-in. One of the things I want to do is to create a new query window and programatically connect it to a server instance (in the context of a SQL Login). I can create the new query script window just fine but I can't find how to connect it without first manually connecting to something else (like the Object Explorer). So in other words, if I connect Obect Explorer to a SQL instance manually and then execute the method of my add-in that creates the query window I can connect it using this code: ServiceCache.ScriptFactory.CreateNewBlankScript( Editors.ScriptType.Sql, ServiceCache.ScriptFactory.CurrentlyActiveWndConnectionInfo.UIConnectionInfo, null); But I don't want to rely on CurrentlyActiveWndConnectionInfo.UIConnectionInfo for the connection. I want to set a SQL Login username and password programatically. Does anyone have any ideas? EDIT: I've managed to get the query window connected by setting the last parameter to an instance of System.Data.SqlClient.SqlConnection. However, the connection uses the context of the last login that was connected instead of what I'm trying to set programatically. That is, the user it connects as is the one selected in the Connection Dialog that you get when you click the New Query button and don't have an Object Explorer connected. EDIT2: I'm writing (or hoping to write) an add-in to automatically send a SQL statement and the execution results to our case-tracking system when run against our production servers. One thought I had was to remove write permissions and assign logins through this add-in which will also force the user to enter a case # canceling the statement if it's not there. Another thought I've just had is to inspect the server name in ServiceCache.ScriptFactory.CurrentlyActiveWndConnectionInfo.UIConnectionInfo and compare it to our list of production servers. If it matches and there's no case # then cancel the query.

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• Haskell Linear Algebra Matrix Library for Arbitrary Element Types

  - by Johannes Weiß

  I'm looking for a Haskell linear algebra library that has the following features: Matrix multiplication Matrix addition Matrix transposition Rank calculation Matrix inversion is a plus and has the following properties: arbitrary element (scalar) types (in particular element types that are not Storable instances). My elements are an instance of Num, additionally the multiplicative inverse can be calculated. The elements mathematically form a finite field (??2256). That should be enough to implement the features mentioned above. arbitrary matrix sizes (I'll probably need something like 100x100, but the matrix sizes will depend on the user's input so it should not be limited by anything else but the memory or the computational power available) as fast as possible, but I'm aware that a library for arbitrary elements will probably not perform like a C/Fortran library that does the work (interfaced via FFI) because of the indirection of arbitrary (non Int, Double or similar) types. At least one pointer gets dereferenced when an element is touched (written in Haskell, this is not a real requirement for me, but since my elements are no Storable instances the library has to be written in Haskell) I already tried very hard and evaluated everything that looked promising (most of the libraries on Hackage directly state that they wont work for me). In particular I wrote test code using: hmatrix, assumes Storable elements Vec, but the documentation states: Low Dimension : Although the dimensionality is limited only by what GHC will handle, the library is meant for 2,3 and 4 dimensions. For general linear algebra, check out the excellent hmatrix library and blas bindings I looked into the code and the documentation of many more libraries but nothing seems to suit my needs :-(. Update Since there seems to be nothing, I started a project on GitHub which aims to develop such a library. The current state is very minimalistic, not optimized for speed at all and only the most basic functions have tests and therefore should work. But should you be interested in using or helping out developing it: Contact me (you'll find my mail address on my web site) or send pull requests.

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• LINQ - How to query a range of effective dates that only has start dates

  - by itchi

  I'm using C# 3.5 and EntityFramework. I have a list of items in the database that contain interest rates. Unfortunately this list only contains the Effective Start Date. I need to query this list for all items within a range. However, I can't see a way to do this without querying the database twice. (Although I'm wondering if delayed execution with EntityFramework is making only one call.) Regardless, I'm wondering if I can do this without using my context twice. internal IQueryable<Interest> GetInterests(DateTime startDate, DateTime endDate) { var FirstDate = Context.All().Where(x => x.START_DATE < startDate).Max(x => x.START_DATE); IQueryable<Interest> listOfItems = Context.All().Where(x => x.START_DATE >= FirstDate && x.START_DATE <= endDate); return listOfItems; }

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• Direct invocation vs indirect invocation in C

  - by Mohit Deshpande

  I am new to C and I was reading about how pointers "point" to the address of another variable. So I have tried indirect invocation and direct invocation and received the same results (as any C/C++ developer could have predicted). This is what I did: int cost; int *cost_ptr; int main() { cost_ptr = &cost; //assign pointer to cost cost = 100; //intialize cost with a value printf("\nDirect Access: %d", cost); cost = 0; //reset the value *cost_ptr = 100; printf("\nIndirect Access: %d", *cost_ptr); //some code here return 0; //1 } So I am wondering if indirect invocation with pointers has any advantages over direct invocation or vice-versa. Some advantages/disadvantages could include speed, amount of memory consumed performing the operation (most likely the same but I just wanted to put that out there), safeness (like dangling pointers) , good programming practice, etc. 1Funny thing, I am using the GNU C Compiler (gcc) and it still compiles without the return statement and everything is as expected. Maybe because the C++ compiler will automatically insert the return statement if you forget.

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• How to create resource manager in ASP.NET

  - by Bart

  Hello, I would like to create resource manager on my page and use some data stored in my resource files. (default.aspx.resx and default.aspx.en.resx) The code looks like this: System.Resources.ResourceManager myResourceManager = System.Resources.ResourceManager.CreateFileBasedResourceManager("resource", Server.MapPath("App_LocalResources") + Path.DirectorySeparatorChar, null); if (User.Identity.IsAuthenticated) { Welcome.Text = myResourceManager.GetString("LoggedInWelcomeText"); } else { Welcome.Text = myResourceManager.GetString("LoggedOutWelcomeText"); } but when i compile and run it on my local server i get this type of error: Could not find any resources appropriate for the specified culture (or the neutral culture) on disk. baseName: resource locationInfo: fileName: resource.resources Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.Resources.MissingManifestResourceException: Could not find any resources appropriate for the specified culture (or the neutral culture) on disk. baseName: resource locationInfo: fileName: resource.resources Source Error: Line 89: else Line 90: { Line 91: Welcome.Text = myResourceManager.GetString("LoggedOutWelcomeText"); Line 92: } Line 93: can you please assist me with this issue?

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• SQL Where Clause Against View

  - by Adam Carr

  I have a view (actually, it's a table valued function, but the observed behavior is the same in both) that inner joins and left outer joins several other tables. When I query this view with a where clause similar to SELECT * FROM [v_MyView] WHERE [Name] like '%Doe, John%' ... the query is very slow, but if I do the following... SELECT * FROM [v_MyView] WHERE [ID] in ( SELECT [ID] FROM [v_MyView] WHERE [Name] like '%Doe, John%' ) it is MUCH faster. The first query is taking at least 2 minutes to return, if not longer where the second query will return in less than 5 seconds. Any suggestions on how I can improve this? If I run the whole command as one SQL statement (without the use of a view) it is very fast as well. I believe this result is because of how a view should behave as a table in that if a view has OUTER JOINS, GROUP BYS or TOP ##, if the where clause was interpreted prior to vs after the execution of the view, the results could differ. My question is why wouldn't SQL optimize my first query to something as efficient as my second query?

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• Is it practical to program with your feet?

  - by bmm

  Has anyone tried using foot pedals in addition to the traditional keyboard and mouse combo to improve your effectiveness in the editor? Any actual experiences out there? Does it work, or is it just for carpal tunnel relief? I found one blog entry from a programmer who actually tried it: So now I can type using my feet for most of the modifier keys. I am using the pedals as I type this. I am still getting used to them, but the burning in my left wrist has definitely reduced. I think I can also type a little faster, but I am too lazy to do the speed tests with and without the pedals to verify this. On the negative side: Working out where to put your feet when you aren’t typing can be a little awkward. The pedals tend to move around the carpet, despite being metal and quite heavy. Some small spikes might have helped. Although the travel on the pedals is small, they are surprisingly stiff. Another programmer's experience: Anybody with hand pain must get foot pedals, since they can remove a tremendous load from your hands. I have two foot pedals, and use one for the SHIFT key, and the other for the CONTROL key. (I still type META by hand.) I have found that in the process of using the Emacs text editor to compose computer programs, I tend to use the SHIFT, CONTROL and META keys constantly, and it is easy to remove most of this load from one's hands. Some foot switch products: Savant Elite Triple Foot Switch FragPedal Bilbo Step On It!

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• Investigating the root cause behind SharePoint's "request not found in the TrackedRequests"

  - by Muhimbi

  We have a long standing issue in our bug tracking system about the dreaded "ERROR: request not found in the TrackedRequests. We might be creating and closing webs on different threads." message in SharePoint's trace log. As we develop Workflow software for the SharePoint market, we look into this issue from time to time to make sure it is not caused by our products. I have personally come to the conclusion that this is a problem in SharePoint, but perhaps someone else can prove me wrong. Here is what I know: According to the hundreds of search results returned by Google on this topic, this issue appears to be mainly related to SharePoint Workflows, both SharePoint Designer and Visual Studio based workflows. Assuming ULS logging is set to Monitorable, the easiest way to reproduce this problem is to create a new SharePoint Designer Workflow, attach it to a document library, set it to auto start on add/update, don't add any actions, save the workflow and upload a file to the document library. The error is only visible in the SharePoint trace log, it does not appear to impact the execution of the workflow at hand. I have verified that the problem occurs on 32 bit as well as 64 bit systems, Win2K3 and 2K8, WSS and MOSS with SharePoint versions up to the December 2009 Cumulative Update (6524). The problem does not occur when a workflow is started manually. There are dozens of related posts on MSDN Forums, hundreds on Google, one on StackOverflow and none on SharePoint Overflow. There appears to be no answer. Does anyone have any idea about what is going on, what is causing this and if we should worry or file this under 'Red Herrings'.

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• jQuery image preload/cache halting browser

  - by Nathan Loding

  In short, I have a very large photo gallery and I'm trying to cache as many of the thumbnail images as I can when the first page loads. There could be 1000+ thumbnails. First question -- is it stupid to try to preload/cache that many? Second question -- when the preload() function fires, the entire browser stops responding for a minute to two. At which time the callback fires, so the preload is complete. Is there a way to accomplish "smart preloading" that doesn't impede on the user experience/speed when attempting to load this many objects? The $.preLoadImages function is take from here: http://binarykitten.me.uk/dev/jq-plugins/107-jquery-image-preloader-plus-callbacks.html Here's how I'm implementing it: $(document).ready(function() { setTimeout("preload()", 5000); }); function preload() { var images = ['image1.jpg', ... 'image1000.jpg']; $.preLoadImages(images, function() { alert('done'); }); } 1000 images is a lot. Am I asking too much?

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• Using prepared statements with JDBCTemplate

  - by Bernhard V

  Hi. I'm using the Jdbc template and want to read from the database using prepared statements. I iterate over many lines in a csv file and on every line I execute some sql select queries with it's values. Now I want to speed up my reading from the database but I just can't get the Jdbc template to work with prepared statements. Actually I even don't know how to do it. There is the PreparedStatementCreator and the PreparedStatementCreator. As in this example both of them are created with anonymous inner classes. But inside the PreparedStatementCreator class I don't have access to the values I want to set in the prepared statement. Since I'm iterating through a csv file I can't hard code them as a String because I don't know them. I also can't pass them to the PreparedStatementCreator because there are no arguments for the constructor. I was used to the creation of prepared statements being fairly simple. Something like PreparedStatement updateSales = con.prepareStatement( "UPDATE COFFEES SET SALES = ? WHERE COF_NAME LIKE ? "); updateSales.setInt(1, 75); updateSales.setString(2, "Colombian"); updateSales.executeUpdate(): as in the Java tutorial. Your help would be very appreciated.

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• Why do people say that Ruby is slow?

  - by stephen murdoch

  I like Ruby on Rails and I use it for all my web development projects. A few years ago there was a lot of talk about Rails being a memory hog and about how it didn't scale very well but these suggestions were put to bed by Gregg Pollack here. Lately though, I've been hearing people saying that Ruby itself is slow. Why is Ruby considered slow? I do not find Ruby to be slow but then again, I'm just using it to make simple CRUD apps and company blogs. What sort of projects would I need to be doing before I find Ruby becoming slow? Or is this slowness just something that affects all programming languages? What are your options as a Ruby programmer if you want to deal with this "slowness"? Which version of Ruby would best suit an application like Stack Overflow where speed is critical and traffic is intense? The questions are subjective, and I realise that architectural setup (EC2 vs standalone servers etc) makes a big difference but I'd like to hear what people think about Ruby being slow. Finally, I can't find much news on Ruby 2.0 - I take it we're a good few years away from that then?

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• What algorithms are suitable for this simple machine learning problem?

  - by user213060

  I have a what I think is a simple machine learning question. Here is the basic problem: I am repeatedly given a new object and a list of descriptions about the object. For example: new_object: 'bob' new_object_descriptions: ['tall','old','funny']. I then have to use some kind of machine learning to find previously handled objects that had similar descriptions, for example, past_similar_objects: ['frank','steve','joe']. Next, I have an algorithm that can directly measure whether these objects are indeed similar to bob, for example, correct_objects: ['steve','joe']. The classifier is then given this feedback training of successful matches. Then this loop repeats with a new object. a Here's the pseudo-code: Classifier=new_classifier() while True: new_object,new_object_descriptions = get_new_object_and_descriptions() past_similar_objects = Classifier.classify(new_object,new_object_descriptions) correct_objects = calc_successful_matches(new_object,past_similar_objects) Classifier.train_successful_matches(object,correct_objects) But, there are some stipulations that may limit what classifier can be used: There will be millions of objects put into this classifier so classification and training needs to scale well to millions of object types and still be fast. I believe this disqualifies something like a spam classifier that is optimal for just two types: spam or not spam. (Update: I could probably narrow this to thousands of objects instead of millions, if that is a problem.) Again, I prefer speed when millions of objects are being classified, over accuracy. What are decent, fast machine learning algorithms for this purpose?

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• Programmatically talking to a Serial Port in OS X or Linux

  - by deadprogrammer

  I have a Prolite LED sign that I like to set up to show scrolling search queries from a apache logs and other fun statistics. The problem is, my G5 does not have a serial port, so I have to use a usb to serial dongle. It shows up as /dev/cu.usbserial and /dev/tty.usbserial . When i do this everything seems to be hunky-dory: stty -f /dev/cu.usbserial speed 9600 baud; lflags: -icanon -isig -iexten -echo iflags: -icrnl -ixon -ixany -imaxbel -brkint oflags: -opost -onlcr -oxtabs cflags: cs8 -parenb Everything also works when I use the serial port tool to talk to it. If I run this piece of code while the above mentioned serial port tool, everthing also works. But as soon as I disconnect the tool the connection gets lost. #!/usr/bin/python import serial ser = serial.Serial('/dev/cu.usbserial', 9600, timeout=10) ser.write("<ID01><PA> \r\n") read_chars = ser.read(20) print read_chars ser.close() So the question is, what magicks do I need to perform to start talking to the serial port without the serial port tool? Is that a permissions problem? Also, what's the difference between /dev/cu.usbserial and /dev/tty.usbserial?

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• Null Reference Exception In LINQ DataContext

  - by Frank

  I have a Null Reference Exception Caused by this code: var recentOrderers = (from p in db.CMS where p.ODR_DATE > DateTime.Today - new TimeSpan(60, 0, 0, 0) select p.SOLDNUM).Distinct(); result = (from p in db.CMS where p.ORDER_ST2 == "SH" && p.ODR_DATE > DateTime.Today - new TimeSpan(365, 0, 0, 0) && p.ODR_DATE < DateTime.Today - new TimeSpan(60, 0, 0, 0) && !(recentOrderers.Contains(p.SOLDNUM))/**/ select p.SOLDNUM).Distinct().Count(); result is of double type. When I comment out: !(recentOrderers.Contains(p.SOLDNUM)) The code runs fine. I have verified that recentOrderers is not null, and when I run: if(recentOrderes.Contains(0)) return; Execution follows this path and returns. Not sure what is going on, since I use similar code above it: var m = (from p in db.CMS where p.ORDER_ST2 == "SH" select p.SOLDNUM).Distinct(); double result = (from p in db.CUST join r in db.DEMGRAPH on p.CUSTNUM equals r.CUSTNUM where p.CTYPE3 == "cmh" && !(m.Contains(p.CUSTNUM)) && r.ColNEWMEMBERDAT.Value.Year > 1900 select p.CUSTNUM).Distinct().Count(); which also runs flawlessly. After noting the similarity, can anyone help? Thanks in advance. -Frank GTP, Inc.

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• Serialization Performance and Google Android

  - by Jomanscool2

  I'm looking for advice to speed up serialization performance, specifically when using the Google Android. For a project I am working on, I am trying to relay a couple hundred objects from a server to the Android app, and am going through various stages to get the performance I need. First I tried a terrible XML parser that I hacked together using Scanner specifically for this project, and that caused unbelievably slow performance when loading the objects (~5 minutes for a 300KB file). I then moved away from that and made my classes implement Serializable and wrote the ArrayList of objects I had to a file. Reading that file into the objects the Android, with the file already downloaded mind you, was taking ~15-30 seconds for the ~100KB serialized file. I still find this completely unacceptable for an Android app, as my app requires loading the data when starting the application. I have read briefly about Externalizable and how it can increase performance, but I am not sure as to how one implements it with nested classes. Right now, I am trying to store an ArrayList of the following class, with the nested classes below it. public class MealMenu implements Serializable{ private String commonsName; private long startMillis, endMillis, modMillis; private ArrayList<Venue> venues; private String mealName; } And the Venue class: public class Venue implements Serializable{ private String name; private ArrayList<FoodItem> foodItems; } And the FoodItem class: public class FoodItem implements Serializable{ private String name; private boolean vegan; private boolean vegetarian; } IF Externalizable is the way to go to increase performance, is there any information as to how java calls the methods in the objects when you try to write it out? I am not sure if I need to implement it in the parent class, nor how I would go about serializing the nested objects within each object.

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