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  • JDBC call not executing

    - by dbyrne
    I am working on one of the DAOs for a medium sized web application. Unfortunately, it contains very convoluted logic, and makes hundreds of JDBC stored proc calls in loops. This is out of my control. I am working on a method inside the DAO which makes a single JDBC call. The simplified version of what this method looks like is this: DriverManager.registerDriver(new com.sybase.jdbc2.jdbc.SybDriver()); Connection con = DriverManager.getConnection((String)connectionDetails.get("DATABASE_URL") (String)connectionDetails.get("USERID"), (String)connectionDetails.get("PASSWORD")); String sqlToExecute = "{call " + STORED_PROC + "(?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)}"; CallableStatement stmt = con.prepareCall(sqlToExecute); //Maybe I should try calling clearParameters here? stmt.setString(1,someData); //....Set of parameters.... if (!stmt.execute()) { //execute method never returns false } stmt.close(); Its pretty much a textbook JDBC call. All this stored proc does is insert a single row. Here is where things get crazy: This code works when you run it through a debugger line by line, but fails when you run it "full speed". Not only does it fail, but it doesn't throw any exception! The execute method always returns true. It just breezes right through the JDBC call without inserting a row to the database. If you go through the log files, copy the stored proc call and run it manually, it works (just like it does in debug mode). Whats strange is that the rest of the DAO, with all its hundreds of looped stored proc calls, works fine. My thinking is that Connection or CallableStatement is caching some value behind the scenes that is screwing things up. Has anyone ever seen anything like this before? A JDBC call failing with no exceptions? I know it will be impossible to provide a complete solution to this without seeing the whole application, I am just looking for suggestions on possible issues to investigate.

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  • std::string insert method has ambiguous overloads?

    - by sdg
    Environment: VS2005 C++ using STLPort 5.1.4. Compiling the following code snippet: std::string copied = "asdf"; char ch = 's'; copied.insert(0,1,ch); I receive an error: Error 1 error C2668: 'stlpx_std::basic_string<_CharT,_Traits,_Alloc>::insert' : ambiguous call to overloaded function It appears that the problem is the insert method call on the string object. The two defined overloads are void insert ( iterator p, size_t n, char c ); string& insert ( size_t pos1, size_t n, char c ); But given that STLPort uses a simple char* as its iterator, the literal zero in the insert method in my code is ambiguous. So while I can easily overcome the problem by hinting such as copied.insert(size_t(0),1,ch); My question is: is this overloading and possible ambiguity intentional in the specification? Or more likely an unintended side-effect of the specific STLPort implementation? (Note that the Microsoft-supplied STL does not have this problem as it has a class for the iterator, instead of a naked pointer)

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  • How to detect .NET WPF memory leak or GC long run?

    - by Néstor Sánchez A.
    I have the next very strange situation and problem: .NET 4.0 application for diagram editing (WPF). Runs ok in my PC: 8GM RAM, 3.0GHz, i7 quad-core. While creating objects (mostly diagram nodes and connectors, plus all the undo/redo information) the TaskManager show, as expected, some memory usage "jumps" (up and down). These mem-usage "jumps" also remains executing AFTER user interaction ended. Maybe this is the GC cleaning/regorganizing memory? To see what is going on, I've used the Ants mem profiler, but somewhat it prevents those "jumps" to happen after user interaction. PROBLEM: It Freezes/Hangs after seconds or minutes of usage in some slow/weak laptos/netbooks of my beta testers (under 2GHz of speed and under 2GB of RAM). I was thinking of a memory leak, but... EDIT: Also, there is the case that the memory usage grows and grows until collapse (only in slow machines). In a Windows XP Mode machine (VM in Win 7) with only 512MB of RAM Assigned it works fine without mem-usage "jumps" after user interaction (no GC cleaning?!). So, I really have a big trouble because I cannot reproduce the error, only see these strange behaviour (mem jumps), and the tool supposed to show me what is happening is hiding the problem (like the "observer's paradox"). Any ideas on what's happening and how to solve it?

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  • NSCollectionView: Can the same object not be in the array more than once or is this a bug?

    - by Sean
    I may be doing this all wrong, but I thought I was on the right track until I hit this little snag. Basically I was putting together a toy using NSCollectionView and trying to understand how to hook that all up using IB. I have a button which will add a couple of strings to the NSArrayController: The first time I press this button, my strings appear in the collection view as expected: The second time I press the button, the views scroll down and room is made - but the items don't appear to get added. I just see blank space: The button is implemented as follows (controller is a pointer to the NSArrayController I added in IB): - (IBAction)addStuff:(id)control { [controller addObjects:[NSArray arrayWithObjects:@"String 1",@"String 2",@"String 3",nil]]; } I'm not sure what I'm doing wrong. Rather than try to explain all the connections/binds/etc, if you need more info, I'd be grateful if you could just take a quick look at the toy project itself. UPDATE: After more experimentation as suggested by James Williams, it seems the problem stems from having multiple objects with the same memory address in the array. This confuses either NSArrayController or NSCollectionView (not sure which). Changing my addStuff: to this resulted in the behavior I originally expected: [controller addObjects:[NSArray arrayWithObjects:[NSMutableString stringWithString:@"String 1"],[NSMutableString stringWithString:@"String 2"],[NSMutableString stringWithString:@"String 3"],nil]]; So the question now, I guess, is if this is a bug I should report to Apple or if this is intended/documented behavior and I just missed it?

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  • How can I improve the performance of LinqToSql queries that use EntitySet properties?

    - by DanM
    I'm using LinqToSql to query a small, simple SQL Server CE database. I've noticed that any operations involving sub-properties are disappointingly slow. For example, if I have a Customer table that is referenced by an Order table, LinqToSql will automatically create an EntitySet<Order> property. This is a nice convenience, allowing me to do things like Customer.Order.Where(o => o.ProductName = "Stopwatch"), but for some reason, SQL Server CE hangs up pretty bad when I try to do stuff like this. One of my queries, which isn't really that complicated takes 3-4 seconds to complete. I can get the speed up to acceptable, even fast, if I just grab the two tables individually and convert them to List<Customer> and List<Order>, then join then manually with my own query, but this is throwing out a lot of what makes LinqToSql so appealing. So, I'm wondering if I can somehow get the whole database into RAM and just query that way, then occasionally save it. Is this possible? How? If not, is there anything else I can do to boost the performance besides resorting to doing all the joins manually? Note: My database in its initial state is about 250K and I don't expect it to grow to more than 1-2Mb. So, loading the data into RAM certainly wouldn't be a problem from a memory point of view. Update Here are the table definitions for the example I used in my question: create table Order ( Id int identity(1, 1) primary key, ProductName ntext null ) create table Customer ( Id int identity(1, 1) primary key, OrderId int null references Order (Id) )

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  • Implementation/interface inheritance design question.

    - by Neil G
    I would like to get the stackoverflow community's opinion on the following three design patterns. The first is implementation inheritance; the second is interface inheritance; the third is a middle ground. My specific question is: Which is best? implementation inheritance: class Base { X x() const = 0; void UpdateX(A a) { y_ = g(a); } Y y_; } class Derived: Base { X x() const { return f(y_); } } interface inheritance: class Base { X x() const = 0; void UpdateX(A a) = 0; } class Derived: Base { X x() const { return x_; } void UpdateX(A a) { x_ = f(g(a)); } X x_; } middle ground: class Base { X x() const { return x_; } void UpdateX(A a) = 0; X x_; } class Derived: Base { void UpdateX(A a) { x_ = f(g(a)); } } I know that many people prefer interface inheritance to implementation inheritance. However, the advantage of the latter is that with a pointer to Base, x() can be inlined and the address of x_ can be statically calculated.

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  • Delphi Pascal / Windows API - Small problem with SetFilePointerEx and parameter FILE_END

    - by SuicideClutchX2
    I know I am about to be slapped by at least one person who was helping me with this API. Alright I have been able to use SetFilePointerEx just fine, when setting the position only. SetFilePointerEx(PD,512,@PositionVar,FILE_BEGIN); SetFilePointerEx(PD,0,@PositionVar,FILE_CURRENT); Both work, I can set positions and even check my current one. But when I set FILE_END as per the documentation no matter what the second parameter is and whether or not i provide a pointer for the third parameter it fails even on a valid handle that many other operations are able to use without fail. For Example: SetFailed := SetFilePointerEx(PD,0,@PositionVar,FILE_END); SetFailed := SetFilePointerEx(PD,0,nil,FILE_END); Whatever I put it fails. I am working with a handle to a physical disk and it most definitely has an end. SetFilePointer works just fine its just a little more trouble than I would like. Its not the end of the world, but whats happening.

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  • How to display many SVGs in Java with high performance

    - by Oak
    What I want My goal is to be able to display a large number of SVG images on a single drawing area in Java, each with its own translation/rotation/scale values. I'm looking for the simplest solution allowing this, optionally even using OpenGL to speed things up. What I've Tried My initial naive approach was to use SVGSalamander to draw directly on a JPanel, but the performance was pathetic. I poked around around and learned that I should do something like manually convert each SVG into a BufferedImage created with createCompatibleImage, then do the transformations I want, then draw it using double buffering. I ran into some troubles here, and before I continued I tried looking for frameworks to simplify things. What I've Looked At I've been a bit overwhelmed by the available options, which is why I'm turning to SO for help. I've looked at: Cairo (with Glitz maybe?) Libart - not sure if this actually supports SVGs FengGUI Slick - looks promising but a bit of an overkill But couldn't decide what is best for me to start working with, and I hope someone here as experience with any of these doing similar things.

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  • Images not showing in ie7 using jquery cycle and jCarouselLite plugin

    - by Geetha
    Hi All, I am using jquery cycle and jCarouselLite plugin to display images as slide. Images are getting displayed in ie7. but working perfect in ie6. Image Property inside the cycle control: Protocol: Not available Type: Not available Address(url): Not available Size: Not available Dimensions: 100X100 but control having the url. if i tried that image url separate it showing the image. Code: $('#slide').cycle({ fx: 'fade', continuous: true, speed: 7500, timeout: 55000, sync: 1 }); Html Code: <div id="slide"> <img src="samp1.jpg" width="664" height="428" border="0" /> <img src="samp2.jpg" width="664" height="428" border="0" /> <img src="samp3.jpg" width="664" height="428" border="0" /> <img src="samp4.jpg" width="664" height="428" border="0" /> <img src="samp5.jpg" width="664" height="428" border="0" /> <img src="samp6.jpg" width="664" height="428" border="0" /> <img src="samp7.jpg" width="664" height="428" border="0" /> <img src="samp8.jpg" width="664" height="428" border="0" /> </div> Geetha.

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  • What is the best approach to 2D collision detection on the iPhone?

    - by Magic Bullet Dave
    Been working on this problem of collision detection and there appears to be 3 main approaches I could take: Sprite and mask approach. (AND the overlap of the sprites and check for a non-zero number in the resulting sprite pixel data). Bounding circles, rectangles or polygons. (Create one or more shapes that enclose the sprites and do the basic maths to check for overlaps). Use an existing sprite library. The first approach, even though it would have been the way I would have done it in the old days of 16x16 sprite blocks, it appears that there just isn’t an easy way of getting at the individual image pixel data and/or alpha channel within Quartz (or OPENGL for that matter). Detecting the overlap of the bounding box is easy, but then creating a 3rd image from the overlap and then testing it for pixels is complicated and my gut feel is that even if we could get it to work would be slow. Am I missing something neat here? The second approach involves dividing up our sprites into several polygons and testing them for overlaps. The more polygons the more accurate the collision detection. The benefit is that it is fast, and can be accurate. The downside is it makes the sprite creation more complicated. i.e., we have to create the polygons for each sprite. For speed the best approach is to create a tree of polygons. The 3rd approach I’m not sure about as it involves buying code (or using an open source licence). I am not sure what the best library to use is or whether this would make life easier or give us a problem integrating this into our app. So in short I am favouring the polygon and tree approach and would appreciate you views on this before I go and write lots of code. Best regards Dave

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  • C# Breakpoint Weirdness

    - by Dan
    In my program I've got two data files A and B. The data in A is static and the data in B refers back to the data in A. In order to make sure the data in B is invalidated when A is changed, I keep an identifier for each of the links which is a long byte-string identifying the data. I get this string using BitConverter on some of the important properties. My problem is that this scheme isn't working. I save the identifiers initially, and with I reload (with the exact same data in A) the identifiers don't match anymore. It seems the bit converter gives different results when I go to save. The really weird thing about it is, if I place a breakpoint in the save code, I can see the identifier it's writing to the file is fine, and the next load works. If I don't place a breakpoint and say print the identifiers to console instead, they're totally different. It's like when my program is running at full-speed the CPU messes up some instructions. This isn't the first time something like this happens to me. I've seen it in other projects. What gives? Has anyone every experienced this kind of debugging weirdness? I can't explain how stopping the program and not stopping it can change the output. Also, it's not a hardware problem because this happens on my laptop as well.

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  • Interchange structured data between Haskell and C

    - by Eonil
    First, I'm a Haskell beginner. I'm planning integrating Haskell into C for realtime game. Haskell does logic, C does rendering. To do this, I have to pass huge complexly structured data (game state) from/to each other for each tick (at least 30 times per second). So the passing data should be lightweight. This state data may laid on sequential space on memory. Both of Haskell and C parts should access every area of the states freely. In best case, the cost of passing data can be copying a pointer to a memory. In worst case, copying whole data with conversion. I'm reading Haskell's FFI(http://www.haskell.org/haskellwiki/FFICookBook#Working_with_structs) The Haskell code look specifying memory layout explicitly. I have a few questions. Can Haskell specify memory layout explicitly? (to be matched exactly with C struct) Is this real memory layout? Or any kind of conversion required? (performance penalty) If Q#2 is true, Any performance penalty when the memory layout specified explicitly? What's the syntax #{alignment foo}? Where can I find the document about this? If I want to pass huge data with best performance, how should I do that? *PS Explicit memory layout feature which I said is just C#'s [StructLayout] attribute. Which is specifying in-memory position and size explicitly. http://www.developerfusion.com/article/84519/mastering-structs-in-c/ I'm not sure Haskell has matching linguistic construct matching with fields of C struct.

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  • getting data from dynamic schema

    - by coure2011
    I am using mongoose/nodejs to get data as json from mongodb. For using mongoose I need to define schema first like this var mongoose = require('mongoose'); var Schema = mongoose.Schema; var GPSDataSchema = new Schema({ createdAt: { type: Date, default: Date.now } ,speed: {type: String, trim: true} ,battery: { type: String, trim: true } }); var GPSData = mongoose.model('GPSData', GPSDataSchema); mongoose.connect('mongodb://localhost/gpsdatabase'); var db = mongoose.connection; db.on('open', function() { console.log('DB Started'); }); then in code I can get data from db like GPSData.find({"createdAt" : { $gte : dateStr, $lte: nextDate }}, function(err, data) { res.writeHead(200, { "Content-Type": "application/json", "Access-Control-Allow-Origin": "*" }); var body = JSON.stringify(data); res.end(body); }); How to define scheme for a complex data like this, you can see that subSection can go to any deeper level. [ { 'title': 'Some Title', 'subSection': [{ 'title': 'Inner1', 'subSection': [ {'titile': 'test', 'url': 'ab/cd'} ] }] }, .. ]

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  • Will Learning C++ Help for Building Fast/No-Additional-Requirements Desktop Applications?

    - by vito
    Will learning C++ help me build native applications with good speed? Will it help me as a programmer, and what are the other benefits? The reason why I want to learn C++ is because I'm disappointed with the UI performances of applications built on top of JVM and .NET. They feel slow, and start slow too. Of course, a really bad programmer can create a slower and sluggish application using C++ too, but I'm not considering that case. One of my favorite Windows utility application is Launchy. And in the Readme.pdf file, the author of the program wrote this: 0.6 This is the first C++ release. As I became frustrated with C#’s large .NET framework requirements and users lack of desire to install it, I decided to switch back to the faster language. I totally agree with the author of Launchy about the .NET framework requirement or even a JRE requirement for desktop applications. Let alone the specific version of them. And some of the best and my favorite desktop applications don't need .NET or Java to run. They just run after installing. Are they mostly built using C++? Is C++ the only option for good and fast GUI based applications? And, I'm also very interested in hearing the other benefits of learning C++.

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  • Approaches to replace cursor in pure AS3 / Flare project?

    - by peteorpeter
    Hi there good lookin, I've got a pure AS3 (no Flex) project that uses Flare to display and interact with a data visualization. I just implemented some panning behavior, so you can click and drag the visualization around, and now I'd like to give the user a visual indicator that this is possible, by switching the arrow cursor with a nice grabby-looking hand icon. The user can click and drag at any time except when the mouse is over a clickable node (at which time the cursor swaps to a pointer - this behavior is already in place). So... 1) Do I need to create my own custom bitmap/sprite or is there a palette of built-in cursors I can use? (I'm not using Flex.) 2) Is there a way to simply replace the default arrow with the pan cursor project-wide, or do I need to attach the swapping to mouse events on display objects? Can I use the stage object to make this behavior apply everywhere? 3) How do I perform the swap? Do I use the Cursor object directly or do I need to get involved with the CursorManager? Any guidance, pseudo-code, or words of wisdom is greatly appreciated!

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  • Serialized NHibernate Configuration objects - detect out of date or rebuild on demand?

    - by fostandy
    I've been using serialized nhibernate configuration objects (also discussed here and here) to speed up my application startup from about 8s to 1s. I also use fluent-nhibernate, so the path is more like ClassMap class definitions in code fluentconfiguration xml nhibernate configuration configuration serialized to disk. The problem from doing this is that one runs the risk of out of date mappings - if I change the mappings but forget to rebuild the serialized configuration, then I end up using the old mappings without realising it. This does not always result in an immediate and obvious error during testing, and several times the misbehaviour has been a real pain to detect and fix. Does anybody have any idea how I would be able to detect if my classmaps have changed, so that I could either issue an immediate warning/error or rebuild it on demand? At the moment I am comparing timestamps on my compiled assembly against the serialized configuration. This will pickup mapping changes, but unfortunately it generates a massive false positive rate as ANY change to the code results in an out of date flag. I can't move the classmaps to another assembly as they are tightly integrated into the business logic. This has been niggling me for a while so I was wondering if anybody had any suggestions?

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  • css style remains after click

    - by rod
    Hi All, I have a simple test page with a single styled button. I'm using a:hover when you hover over the button. However, when you click the button the a:hover style remains until I click on something else. How would I fix this and why is this happening? Thanks, rod. <asp:Content ID="indexContent" ContentPlaceHolderID="MainContent" runat="server"> <% using (Ajax.BeginForm(new AjaxOptions { })) { %> <div id="detailActions"> <a href="#">Delete User</a> </div> <% } %> </asp:Content> My CSS: #detailActions { margin-bottom: 7px; padding: 3px 0px 5px 0px; } #detailActions { padding: 1px 7px 1px 7px; margin: 0px 5px 0px 0px; border: solid 1px gray; background-color: #ADD8E6; cursor: pointer; width: auto !important; font-weight: bold; text-decoration: none; color: #003366; font-size: 1.2em; } #detailActions a:hover, #detailActions a:active, #detailActions a:focus { color: White; background-color: #00008B; }

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  • wpf: capturing mouse does not work

    - by amethyste
    hello I am developing an kind of outlook calendar application where I need to make the appointment resizable from mouse. My first try with a thumb did not work properly so I tried another way. What I did is that: 1) on the botton of the appointmennt panel I added a rectangle to figure out the resize zone (the thumb). The appointment panel is put on a grid panel. 2) I intercept down event on the rectangle and send event to this code: private Point startPoint; private void OnResizeElementMouseDown(object sender, MouseButtonEventArgs e) { e.Handled = true; this.MouseMove += new MouseEventHandler(ResizeEndElement_MouseMove); this.MouseLeftButtonUp += new MouseButtonEventHandler(OnResizeElementMouseUp); // some code to perform new height computation Mouse.Capture(this); } where this is the appointment panel that own the thumb. Decreasing height works well. But increasing is more difficult. If I move the mouse very very slowly it's OK, if I speed it up a little bit it tends to leave out the appointment panel and then all MouseMove event are lost. I thought Mouse.Capture() was propose to solve this kind of problem, but in fact not. Does anybody know what is wrong in my code?

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  • Invoking a function (main()) from a binary file in C

    - by Dhara Darji
    I have simple c program like, my_bin.c: #include <stdio.h> int main() { printf("Success!\n"); return 0; } I compile it with gcc and got executable: my_bin. Now I want to invoke main (or run this my_bin) using another C program. That I did with mmap and function pointer like this: #include <stdio.h> #include <fcntl.h> #include <sys/mman.h> int main() { void (*fun)(); int fd; int *map; fd = open("./my_bin", O_RDONLY); map = mmap(0, 8378, PROT_READ, MAP_SHARED, fd, 0); fun = map; fun(); return 0; } PS: I went through some tutorial, for how to read binary file and execute. But this gives Seg fault, any help appreciated! Thanks!

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  • Who's setting TCP window size down to 0, Indy or Windows?

    - by François
    We have an application server which have been observed sending headers with TCP window size 0 at times when the network had congestion (at a client's site). We would like to know if it is Indy or the underlying Windows layer that is responsible for adjusting the TCP window size down from the nominal 64K in adaptation to the available throughput. And we would be able to act upon it becoming 0 (nothing gets send, users wait = no good). So, any info, link, pointer to Indy code are welcome... Disclaimer: I'm not a network specialist. Please keep the answer understandable for the average me ;-) Note: it's Indy9/D2007 on Windows Server 2003 SP2. More gory details: The TCP zero window cases happen on the middle tier talking to the DB server. It happens at the same moments when end users complain of slowdowns in the client application (that's what triggered the network investigation). 2 major Network issues causing bottlenecks have been identified. The TCP zero window happened when there was network congestion, but may or may not be caused by it. We want to know when that happen and have a way to do something (logging at least) in our code. So where to hook (in Indy?) to know when that condition occurs?

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  • High Runtime for Dictionary.Add for a large amount of items

    - by aaginor
    Hi folks, I have a C#-Application that stores data from a TextFile in a Dictionary-Object. The amount of data to be stored can be rather large, so it takes a lot of time inserting the entries. With many items in the Dictionary it gets even worse, because of the resizing of internal array, that stores the data for the Dictionary. So I initialized the Dictionary with the amount of items that will be added, but this has no impact on speed. Here is my function: private Dictionary<IdPair, Edge> AddEdgesToExistingNodes(HashSet<NodeConnection> connections) { Dictionary<IdPair, Edge> resultSet = new Dictionary<IdPair, Edge>(connections.Count); foreach (NodeConnection con in connections) { ... resultSet.Add(nodeIdPair, newEdge); } return resultSet; } In my tests, I insert ~300k items. I checked the running time with ANTS Performance Profiler and found, that the Average time for resultSet.Add(...) doesn't change when I initialize the Dictionary with the needed size. It is the same as when I initialize the Dictionary with new Dictionary(); (about 0.256 ms on average for each Add). This is definitely caused by the amount of data in the Dictionary (ALTHOUGH I initialized it with the desired size). For the first 20k items, the average time for Add is 0.03 ms for each item. Any idea, how to make the add-operation faster? Thanks in advance, Frank

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  • JSP Upload File Java.lang.NullPointer

    - by newbie123
    I want to develope upload and download file from server. Upload.html <form action="/UploadFile/UploadFile" method="POST" enctype="multipart/form-data">Select a file: <input type="submit" name="button" /> <input type="file" name="first"></form> UploadFile.servlet protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String temp = request.getParameter("first"); System.out.println(temp); File origFile = new File(temp); FileOutputStream out = new FileOutputStream(request.getContextPath() + "pdtImages/" + "FirstFile"); InputStream ins = new FileInputStream(origFile); try { System.out.println(request.getContextPath()); byte[] buf = new byte[1024]; int len; while ((len = ins.read(buf)) > 0) { out.write(buf, 0, len); } out.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } When I submitted the file I got null pointer error message. I not very familiar with jsp can anybody help me? I want to store the file to the server directory.

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  • Matlab matrix translation and rotation multiple times

    - by pinnacler
    I have a map of individual trees from a forest stored as x,y points in a matrix. I call it fixedPositions. It's cartesian and (0,0) is the origin. I would like 0/360 degrees to be the top of the screen and 90 degrees to be to the right. Given a velocity and a heading, i.e. .5 m/s and 60 degrees (2 o'clock equivalent on a watch), how do I rotate that x,y points, so that the new origin is centered at (.5cos(60),.5sin(60)) and 60 degrees is now at the top of the screen? Then if I were to give you another heading and speed, i.e. 0 degrees and 2m/s, it should calculate it from the last point, not the original fixedPositions origin. I've wasted my day trying to figure this out. I wish I took matrix algebra but I'm at a loss. I tried doing cos(30) and even those wouldn't compute correctly, which after an hour I realize were in radians.

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  • iPhone OpenGL ES Texture2D Masking

    - by Robert Neagu
    What's the best choice when trying to mask a texture like ColorSplash or other apps like iSteam, etc? I started learning OPENGL ES like... 4 days ago (I'm a total rookie) and tried the following approach: 1) I created a colored texture2D, a grayscale version of the first texture and a third texture2D called mask 2) I also created a texture2D for the brush... which is grayscale and it's opaque (brush = black = 0,0,0,1 and surroundings = white = 1,1,1,1). My intention was to create an antialiased brush with smooth edges but i'm fine with a normal one right now 3) I searched for masking techniques on the internet and found this tutorial ZeusCMD - Design and Development Tutorials : OpenGL ES Programming Tutorials - Masking about masking. The tutorial tells me to use blending to achieve masking... first draw colored, then mask with glBlendFunc(GL_DST_COLOR, GL_ZERO) and then grayscale with glBlendFunc(GL_ONE, GL_ONE) ... and this gives me something close to what i want... but not exactly what i want. The result is masked but it's somehow overbright-ed 4) For drawing to the mask texture i used an extra frame buffer object (FBO) I'm not really happy with the resulting image (overbright-ed picture) nor with the speed achieved with this method. I think the normal way was to draw directly to the grayscale (overlay) texture2D affecting only it's alpha channel in the places where the brush hits. Is there a fast way to achieve this? I have searched a lot and never got an answer that's clear and understandable. Then, in the main draw loop I could only draw the colored texture and then blend the grayscale ontop with glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA). I just want to learn to use OPENGL ES and it's driving me nuts because i can't get it to work properly. An advice, a link to a tutorial would be much appreciated.

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  • real time stock quotes, StreamReader performance optimization

    - by sean717
    I am working on a program that extracts real time quote for 900+ stocks from a website. I use HttpWebRequest to send HTTP request to the site and store the response to a stream and open a stream using the following code: HttpWebResponse response = (HttpWebResponse)request.GetResponse(); Stream stream = response.GetResponseStream (); StreamReader reader = new StreamReader( stream ) the size of the received HTML is large (5000+ lines), so it takes a long time to parse it and extract the price. For 900 files, It takes about 6 mins for parsing and extracting. Which my boss isn't happy with, he told me he'd want the whole process to be done in TWO mins. I've identified the part of the program that takes most of time to finish is parsing and extracting. I've tried to optimize the code to make it faster, the following is what I have now after some optimization: // skip lines at the top for(int i=0;i<1500;++i) reader.ReadLine(); // read the line that contains the price string theLine = reader.ReadLine(); // ... extract the price from the line now it takes about 4 mins to process all the files, there is still a significant gap to what my boss's expecting. So I am wondering, is there other way that I can further speed up the parsing and extracting and have everything done within 2 mins?

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