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  • How to split HTML code with javascript or JQuery

    - by Dean
    Hi I'm making a website using JSP and servlets and I have to now break up a list of radio buttons to insert a textarea and a button. I have got the button and textarea to hide and show when you click on the radio button it shows the text area and button. But this only appears at the top and when there are hundreds on the page this will become awkward so i need a way for it to appear underneath. Here is what my HTML looks like when complied: <form action="addSpotlight" method="POST"> <table> <tr><td><input type="radio" value="29" name="publicationIDs" ></td><td>A System For Dynamic Server Allocation in Application Server Clusters, IEEE International Symposium on Parallel and Distributed Processsing with Applications, 2008</td> </tr> <tr><td><input type="radio" value="30" name="publicationIDs" ></td><td>Analysing BitTorrent's Seeding Strategies, 7th IEEE/IFIP International Conference on Embedded and Ubiquitous Computing (EUC-09), 2009</td> </tr> <tr><td><input type="radio" value="31" name="publicationIDs" ></td><td>The Effect of Server Reallocation Time in Dynamic Resource Allocation, UK Performance Engineering Workshop 2009, 2009</td> </tr> <tr><td><input type="radio" value="32" name="publicationIDs" ></td><td>idk, hello, 1992</td> </tr> <tr><td><input type="radio" value="33" name="publicationIDs" ></td><td>sad, safg, 1992</td> </tr> <div class="abstractWriteup"><textarea name="abstract"></textarea> <input type="submit" value="Add Spotlight"></div> </table> </form> Now here is what my JSP looks like: <form action="addSpotlight" method="POST"> <table> <%int i = 0; while(i<ids.size()){%> <tr><td><input type="radio" value="<%=ids.get(i)%>" name="publicationIDs" ></td><td><%=info.get(i)%></td> </tr> <%i++; }%> <div class="abstractWriteup"><textarea name="abstract"></textarea> <input type="submit" value="Add Spotlight"></div> </table> </form> Thanks in Advance Dean

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  • Running Network Application on port Server side give me error how can i solve it?

    - by Phsika
    if i run Server App. Exception occurs: on Dinle.Start() System.Net.SocketException - Only one usage of each socket address (protocol/network address/port) is normally permitted How can i solve this error? Server.cs using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.IO; using System.Net; using System.Net.Sockets; using System.Threading; namespace Server { public partial class Server : Form { Thread kanal; public Server() { InitializeComponent(); try { kanal = new Thread(new ThreadStart(Dinle)); kanal.Start(); kanal.Priority = ThreadPriority.Normal; this.Text = "Kanla Çalisti"; } catch (Exception ex) { this.Text = "kanal çalismadi"; MessageBox.Show("hata:" + ex.ToString()); kanal.Abort(); throw; } } private void Server_Load(object sender, EventArgs e) { Dinle(); } private void btn_Listen_Click(object sender, EventArgs e) { Dinle(); } void Dinle() { // IPAddress localAddr = IPAddress.Parse("localhost"); // TcpListener server = new TcpListener(port); // server = new TcpListener(localAddr, port); //TcpListener Dinle = new TcpListener(localAddr,51124); TcpListener Dinle = new TcpListener(51124); try { while (true) { Dinle.Start(); Exception is occured. Socket Baglanti = Dinle.AcceptSocket(); if (!Baglanti.Connected) { MessageBox.Show("Baglanti Yok"); } else { TcpClient tcpClient = Dinle.AcceptTcpClient(); if (tcpClient.ReceiveBufferSize 0) { byte[] Dizi = new byte[250000]; Baglanti.Receive(Dizi, Dizi.Length, 0); string Yol; saveFileDialog1.Title = "Dosyayi kaydet"; saveFileDialog1.ShowDialog(); Yol = saveFileDialog1.FileName; FileStream Dosya = new FileStream(Yol, FileMode.Create); Dosya.Write(Dizi, 0, Dizi.Length - 20); Dosya.Close(); listBox1.Items.Add("dosya indirildi"); listBox1.Items.Add("Dosya Boyutu=" + Dizi.Length.ToString()); listBox1.Items.Add("Indirilme Tarihi=" + DateTime.Now); listBox1.Items.Add("--------------------------------"); } } } } catch (Exception ex) { MessageBox.Show("hata:" + ex.ToString()); } } } }

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  • WordPress Write Cache Problem with Multiple Sessions

    - by Volomike
    I'm working on a content dripper custom plugin in WordPress that my client asked me to build. He says he wants it to catch a page view event, and if it's the right time of day (24 hours since last post), to pull from a resource file and output another post. He needed it to also raise a flag and prevent other sessions from firing that same snippet of code. So, raise some kind of flag saying, "I'm posting that post, go away other process," and then it makes that post and releases the flag again. However, the strangest thing is occurring when placed under load with multiple sessions hitting the site with page views. It's firing instead of one post -- it's randomly doing like 1, 2, or 3 extra posts, with each one thinking that it was the right time to post because it was 24 hours past the time of the last post. Because it's somewhat random, I'm guessing that the problem is some kind of write caching where the other sessions don't see the raised flag just yet until a couple microseconds pass. The plugin was raising the "flag" by simply writing to the wp_options table with the update_option() API in WordPress. The other user sessions were supposed to read that value with get_option() and see the flag, and then not run that piece of code that creates the post because a given session was already doing it. Then, when done, I lower the flag and the other sessions continue as normal. But what it's doing is letting those other sessions in. To make this work, I was using add_action('loop_start','checkToAddContent'). The odd thing about that function though is that it's called more than once on a page, and in fact some plugins may call it. I don't know if there's a better event to hook. Even still, even if I find an event to hook that only runs once on a page view, I still have multiple sessions to contend with (different users who may view the page at the same time) and I want only one given session to trigger the content post when the post is due on the schedule. I'm wondering if there are any WordPress plugin devs out there who could suggest another event hook to latch on to, and to figure out another way to raise a flag that all sessions would see. I mean, I could use the shared memory API in PHP, but many hosting plans have that disabled. Can't use a cookie or session var because that's only one single session. About the only thing that might work across hosting plans would be to drop a file as a flag, instead. If the file is present, then one session has the flag. If the file is not present, then other sessions can attempt to get the flag. Sure, I could use the file route, but it's kind of immature in my opinion and I was wondering if there's something in WordPress I could do.

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  • TicTacToe AI Making Incorrect Decisions

    - by Chris Douglass
    A little background: as a way to learn multinode trees in C++, I decided to generate all possible TicTacToe boards and store them in a tree such that the branch beginning at a node are all boards that can follow from that node, and the children of a node are boards that follow in one move. After that, I thought it would be fun to write an AI to play TicTacToe using that tree as a decision tree. TTT is a solvable problem where a perfect player will never lose, so it seemed an easy AI to code for my first time trying an AI. Now when I first implemented the AI, I went back and added two fields to each node upon generation: the # of times X will win & the # of times O will win in all children below that node. I figured the best solution was to simply have my AI on each move choose and go down the subtree where it wins the most times. Then I discovered that while it plays perfect most of the time, I found ways where I could beat it. It wasn't a problem with my code, simply a problem with the way I had the AI choose it's path. Then I decided to have it choose the tree with either the maximum wins for the computer or the maximum losses for the human, whichever was more. This made it perform BETTER, but still not perfect. I could still beat it. So I have two ideas and I'm hoping for input on which is better: 1) Instead of maximizing the wins or losses, instead I could assign values of 1 for a win, 0 for a draw, and -1 for a loss. Then choosing the tree with the highest value will be the best move because that next node can't be a move that results in a loss. It's an easy change in the board generation, but it retains the same search space and memory usage. Or... 2) During board generation, if there is a board such that either X or O will win in their next move, only the child that prevents that win will be generated. No other child nodes will be considered, and then generation will proceed as normal after that. It shrinks the size of the tree, but then I have to implement an algorithm to determine if there is a one move win and I think that can only be done in linear time (making board generation a lot slower I think?) Which is better, or is there an even better solution?

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  • Does this mySQL Stored Procedure Work?

    - by Laxmidi
    Hi, I got the following stored procedure from http://dev.mysql.com/doc/refman/5.1/en/functions-that-test-spatial-relationships-between-geometries.html Does this work? CREATE FUNCTION myWithin(p POINT, poly POLYGON) RETURNS INT(1) DETERMINISTIC BEGIN DECLARE n INT DEFAULT 0; DECLARE pX DECIMAL(9,6); DECLARE pY DECIMAL(9,6); DECLARE ls LINESTRING; DECLARE poly1 POINT; DECLARE poly1X DECIMAL(9,6); DECLARE poly1Y DECIMAL(9,6); DECLARE poly2 POINT; DECLARE poly2X DECIMAL(9,6); DECLARE poly2Y DECIMAL(9,6); DECLARE i INT DEFAULT 0; DECLARE result INT(1) DEFAULT 0; SET pX = X(p); SET pY = Y(p); SET ls = ExteriorRing(poly); SET poly2 = EndPoint(ls); SET poly2X = X(poly2); SET poly2Y = Y(poly2); SET n = NumPoints(ls); WHILE i<n DO SET poly1 = PointN(ls, (i+1)); SET poly1X = X(poly1); SET poly1Y = Y(poly1); IF ( ( ( ( poly1X <= pX ) && ( pX < poly2X ) ) || ( ( poly2X <= pX ) && ( pX < poly1X ) ) ) && ( pY > ( poly2Y - poly1Y ) * ( pX - poly1X ) / ( poly2X - poly1X ) + poly1Y ) ) THEN SET result = !result; END IF; SET poly2X = poly1X; SET poly2Y = poly1Y; SET i = i + 1; END WHILE; RETURN result; End; Usage: SET @point = PointFromText('POINT(5 5)') ; SET @polygon = PolyFromText('POLYGON((0 0,10 0,10 10,0 10))') ; SELECT myWithin(@point, @polygon) AS result ; I'm using phpMyAdmin and it blows up when using stored procedures. If this one works, then I'll try to figure out how to call it in php instead. Thanks, Laxmidi

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  • Constructor Injection and when to use a Service Locator

    - by Simon
    I'm struggling to understand parts of StructureMap's usage. In particular, in the documentation a statement is made regarding a common anti-pattern, the use of StructureMap as a Service Locator only instead of constructor injection (code samples straight from Structuremap documentation): public ShippingScreenPresenter() { _service = ObjectFactory.GetInstance<IShippingService>(); _repository = ObjectFactory.GetInstance<IRepository>(); } instead of: public ShippingScreenPresenter(IShippingService service, IRepository repository) { _service = service; _repository = repository; } This is fine for a very short object graph, but when dealing with objects many levels deep, does this imply that you should pass down all the dependencies required by the deeper objects right from the top? Surely this breaks encapsulation and exposes too much information about the implementation of deeper objects. Let's say I'm using the Active Record pattern, so my record needs access to a data repository to be able to save and load itself. If this record is loaded inside an object, does that object call ObjectFactory.CreateInstance() and pass it into the active record's constructor? What if that object is inside another object. Does it take the IRepository in as its own parameter from further up? That would expose to the parent object the fact that we're access the data repository at this point, something the outer object probably shouldn't know. public class OuterClass { public OuterClass(IRepository repository) { // Why should I know that ThingThatNeedsRecord needs a repository? // that smells like exposed implementation to me, especially since // ThingThatNeedsRecord doesn't use the repo itself, but passes it // to the record. // Also where do I create repository? Have to instantiate it somewhere // up the chain of objects ThingThatNeedsRecord thing = new ThingThatNeedsRecord(repository); thing.GetAnswer("question"); } } public class ThingThatNeedsRecord { public ThingThatNeedsRecord(IRepository repository) { this.repository = repository; } public string GetAnswer(string someParam) { // create activeRecord(s) and process, returning some result // part of which contains: ActiveRecord record = new ActiveRecord(repository, key); } private IRepository repository; } public class ActiveRecord { public ActiveRecord(IRepository repository) { this.repository = repository; } public ActiveRecord(IRepository repository, int primaryKey); { this.repositry = repository; Load(primaryKey); } public void Save(); private void Load(int primaryKey) { this.primaryKey = primaryKey; // access the database via the repository and set someData } private IRepository repository; private int primaryKey; private string someData; } Any thoughts would be appreciated. Simon

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  • Creating a spam list with a web crawler in python

    - by user313623
    Hey guys, I'm not trying to do anything malicious here, I just need to do some homework. I'm a fairly new programmer, I'm using python 3.0, and I having difficulty using recursion for problem-solving. I've been stuck on this question for quite a while. Here's the assignment: Write a recursive method spam(url, n) that takes a url of a web page as input and a non-negative integer n, collects all the email address contained in the web page and adds them to a global dictionary variable spam_dict, and then recursively calls itself on every http hyperlink contained in the web page. You will use a dictionary so only one copy of every email address is save; your dictionary will store (key,value) pairs (email, email). The recursive call should use the parameter n-1 instead of n. If n = 0, you should collect the email addresses but no recursive calls should be made. The parameter n is used to limit the recursion to at most depth n. You will need to use the solutions of the two above problems; you method spam() will call the methods links2() and emails() and possibly other functions as well. Notes: 1. running spam() directly will produce no output on the screen; to find your spam_dict, you will need to read the value of spam_dict, and you will also need to reset it to the empty dictionary before every run of spam. 2. Recall how global variables are used. Usage: spam_dict = {} spam('http://reed.cs.depaul.edu/lperkovic/csc242/test1.html',0) spam_dict.keys() dict_keys([]) spam_dict = {} spam('http://reed.cs.depaul.edu/lperkovic/csc242/test1.html',1) spam_dict.keys() dict_keys(['[email protected]', '[email protected]']) So far, I've written a function that traverses web pages and puts all the links in a nice little list, and what I wanted to do was call that functions. And why would I use recursion on a dictionary? And how? I don't understand how n ties into all of this. def links2(url): content = str(urlopen(url).read()) myparser = MyHTMLParser() myparser.feed(content) lst = myparser.get() mergelst = [] for link in lst: mergelst.append(urljoin(lst[0],link)) print(mergelst) Any input (except why spam is bad) would be greatly appreciated. Also, I realize that the above function could probably look better, if you have a way to do it, I'm all ears. However, all I need is the point is for the program to produce the proper output.

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  • Good working habits to observe in project development?

    - by Will Marcouiller
    As my development experience grows, I see fit to stick to best practices from here and there to build somehow my own working practices while observing the conventions, etc. I'm currently working on a project which my goals is to graduate the security access model from an environment's Active Directory to another environment's automatically. I don't know for any of you, but as far as I'm concerned, I meet some real difficulties sticking to only one way, then develop. I mean, I learn something new everyday while visiting SO, and recently wanted to get acquainted with generics. On the other hand, I better know the Façade pattern which proved to be very practical in transactional programming in process systems. This seems to be less practical for desktop application as there are plenty of variables to consider in a desktop application that you don't have to care in transactional programming, as you're playing only with information data. As for my current project, I have: Groups; Organizational Units; Users. Which are all considered an entry in the Active Directory. This points out to be a good candidate for generics, as also approached this way by Bart de Smett's Linq to AD on CodePlex. He has a DirectorySource<T>, and to manage let's say groups, then he instantiate a source with the proper type: var groups = new DirectorySource<Group>(); This seems to be very a good way of doing. Despite, I seem to go from one pattern to another and I don't seem to be able to strictly stick to one. While I'm aware that one must not stay with only one way of doing, since each pattern statisfies certain advantages, while also illustrating disadvantages under some usage conditions, I seem to want to develop with both patterns having a singleton Façade class with the underlying factories which represent the sub systems: GroupsFactory; UsersFactory; OrganizationalUnitsFactory. Each of the factories offers the possible operations for their respective entity (group, user, OU). To make a very long story short, I often have plenty of ideas while developping and this causes me some trouble, as I go from an idea to another feeling completely lost after a while. Yet I understand the advantages and disavantages, I have no trouble choosing from one pattern to another depending on the situation. Nevertheless, when it comes to programming itself, if I'm not part of a team, I feel sometimes like I can't do anything good. That is, because I can't stand not doing something "perfect" the first time. The role I play within the project is both: the project manager and the programmer. I am more comfortable in the project manager role, architectural role, analytical role than the developer's. Has any of you some good habbits to observe in project development? Thanks to you all! =)

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  • WPF - ListBox ignores Style When ItemsSource is bound

    - by Andy T
    Hi, I have created styled a ListBox in WPF so that it is rendered as a checkbox list. When I populate the ListBox's items manually, the styling works perfectly. However, when I instead bind the ItemsSource of the ListBox to a static resource (an ItemsControl containing the required items), the styling is completely dropped. Here's the style: <Style x:Key="CheckBoxListStyle" TargetType="ListBox"> <Style.Resources> <Style TargetType="ListBoxItem"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="ListBoxItem"> <Grid Margin="2"> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" /> <ColumnDefinition /> </Grid.ColumnDefinitions> <CheckBox IsChecked="{Binding IsSelected, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"/> <ContentPresenter Grid.Column="1" Margin="2,0,0,0" /> </Grid> </ControlTemplate> </Setter.Value> </Setter> </Style> </Style.Resources> <Setter Property="ItemsPanel"> <Setter.Value> <ItemsPanelTemplate> <WrapPanel Orientation="Vertical" /> </ItemsPanelTemplate> </Setter.Value> </Setter> <Setter Property="BorderThickness" Value="0" /> <Setter Property="Background" Value="Transparent" /> </Style> Here's the code for the ListBox that shows the style correctly: <ListBox x:Name="ColumnsList" Grid.Column="0" Grid.Row="0" Style="{StaticResource CheckBoxListStyle}" BorderThickness="1"> <ListBox.Items> <ListBoxItem>Test</ListBoxItem> <ListBoxItem>Test2</ListBoxItem> <ListBoxItem>Test3</ListBoxItem> </ListBox.Items> </ListBox> Here's the code for the ListBox that ignores the style: <ListBox x:Name="ColumnsList2" Grid.Column="0" Grid.Row="0" Style="{StaticResource CheckBoxListStyle}" BorderThickness="1" ItemsSource="{Binding Source={StaticResource Test1}, Path=Items}"> </ListBox> Hoping someone can help - I'm pretty new to all this and have tried everything I can think of, but everything I've read leads me to believe that setting ItemsSource should have the same outcome as setting the items manually, so I can't see any reason why this would not work. Thanks, AT

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  • cannot retrieve effect.fx file

    - by numerical25
    I am having issues loading my effect.fx from directx. When I step into my application, my ID3D10Effect *m_pDefaultEffect; pointer remains empty. the address remains at 0x000000 below is my code #pragma once #include "stdafx.h" #include "resource.h" #include "d3d10.h" #include "d3dx10.h" #include "dinput.h" #define MAX_LOADSTRING 100 class RenderEngine { protected: RECT m_screenRect; //direct3d Members ID3D10Device *m_pDevice; // The IDirect3DDevice10 // interface ID3D10Texture2D *m_pBackBuffer; // Pointer to the back buffer ID3D10RenderTargetView *m_pRenderTargetView; // Pointer to render target view IDXGISwapChain *m_pSwapChain; // Pointer to the swap chain RECT m_rcScreenRect; // The dimensions of the screen ID3D10Texture2D *m_pDepthStencilBuffer; ID3D10DepthStencilState *m_pDepthStencilState; ID3D10DepthStencilView *m_pDepthStencilView; //transformation matrixs D3DXMATRIX g_mtxWorld; D3DXMATRIX g_mtxView; D3DXMATRIX g_mtxProj; //Effect members ID3D10Effect *m_pDefaultEffect; ID3D10EffectTechnique *m_pDefaultTechnique; ID3DX10Font *m_pFont; // The font used for rendering text // Sprites used to hold font characters ID3DX10Sprite *m_pFontSprite; ATOM RegisterEngineClass(); void DoFrame(float); bool LoadEffects(); public: static HINSTANCE m_hInst; HWND m_hWnd; int m_nCmdShow; TCHAR m_szTitle[MAX_LOADSTRING]; // The title bar text TCHAR m_szWindowClass[MAX_LOADSTRING]; // the main window class name void DrawTextString(int x, int y, D3DXCOLOR color, const TCHAR *strOutput); //static functions static LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam); static INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam); bool InitWindow(); bool InitDirectX(); bool InitInstance(); int Run(); void ShutDown(); RenderEngine() { m_screenRect.right = 800; m_screenRect.bottom = 600; } }; below is the implementation bool RenderEngine::LoadEffects() { HRESULT hr; ID3D10Blob *pErrors = 0; // Create the default rendering effect hr = D3DX10CreateEffectFromFile(L"effect.fx", NULL, NULL, "fx_4_0", D3D10_SHADER_DEBUG, 0, m_pDevice, NULL, NULL, &m_pDefaultEffect, &pErrors, NULL); if(pErrors)// at this point, m_pDefaultEffect is still empty but pErrors returns data which means there is {//errors return false; //ends here } //m_pDefaultTechnique = m_pDefaultEffect->GetTechniqueByName("DefaultTechnique"); return true; } My directx Device does work. My effect.fx file is in the same folder as my solution files (.cpp and header files)

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  • Bogus WPF / XAML errors in Visual Studio 2010

    - by epalm
    There are bogus errors hanging around, but at runtime everything works. Right now, I'm getting Cannot locate resource 'img/icons/silk/arrow_refresh.png'. I've got a simple UserControl called ImageButton (doesn't everyone?): <UserControl x:Class="WinDispatchClientWpf.src.controls.ImageButton" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" mc:Ignorable="d"> <Button Name="btnButton" Click="btnButton_Click"> <StackPanel Orientation="Horizontal"> <Image Name="btnImage" Stretch="None" /> <TextBlock Name="btnText" /> </StackPanel> </Button> </UserControl> Which does what you'd expect: [ContentProperty("Text")] public partial class ImageButton : UserControl { public String Image { set { btnImage.Source = GuiUtil.CreateBitmapImage(value); } } public String Text { set { btnText.Text = value; } } public double Gap { set { btnImage.Margin = new Thickness(0, 0, value, 0); } } public bool ToolBarStyle { set { if (value) { btnButton.Style = (Style)FindResource(ToolBar.ButtonStyleKey); } } } public bool IsCancel { set { btnButton.IsCancel = value; } } public bool IsDefault { set { btnButton.IsDefault = value; } } public event RoutedEventHandler Click; public ImageButton() { InitializeComponent(); } private void btnButton_Click(object sender, RoutedEventArgs e) { if (Click != null) { Click(sender, e); } } } Where CreateBitmapImage is the following: public static BitmapImage CreateBitmapImage(string imagePath) { BitmapImage icon = new BitmapImage(); icon.BeginInit(); icon.UriSource = new Uri(String.Format("pack://application:,,,/{0}", imagePath)); icon.EndInit(); return icon; } I can't see the design view of any xaml file that uses an ImageButton like such: <Window foo="bar" xmlns:wpfControl="clr-namespace:MyProj.src.controls"> <Grid> <wpfControl:ImageButton ToolBarStyle="True" Gap="3" Click="btnRefresh_Click" Text="Refresh" Image="img/icons/silk/arrow_refresh.png" /> </Grid> </Window> Why is VS complaining?

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  • What is a good platform for building a game framework targetting both web and native languages?

    - by fuzzyTew
    I would like to develop (or find, if one is already in development) a framework with support for accelerated graphics and sound built on a system flexible enough to compile to the following: native ppc/x86/x86_64/arm binaries or a language which compiles to them javascript actionscript bytecode or a language which compiles to it (actionscript 3, haxe) optionally java I imagine, for example, creating an API where I can open windows and make OpenGL-like calls and the framework maps this in a relatively efficient manner to either WebGL with a canvas object, 3d graphics in Flash, OpenGL ES 2 with EGL, or desktop OpenGL in an X11, Windows, or Cocoa window. I have so far looked into these avenues: Building the game library in haXe Pros: Targets exist for php, javascript, actionscript bytecode, c++ High level, object oriented language Cons: No support for finally{} blocks or destructors, making resource cleanup difficult C++ target does not allow room for producing highly optimized libraries -- the foreign function interface requires all primitive types be boxed in a wrapper object, as if writing bindings for a scripting language; these feel unideal for real-time graphics and audio, especially exporting low-level functions. Doesn't seem quite yet mature Using the C preprocessor to create a translator, writing programs entirely with macros Pros: CPP is widespread and simple to use Cons: This is an arduous task and probably the wrong tool for the job CPP implementations differ widely in support for features (e.g. xcode cpp has no variadic macros despite claiming C99 compliance) There is little-to-no room for optimization in this route Using llvm's support for multiple backends to target c/c++ to web languages Pros: Can code in c/c++ LLVM is a very mature highly optimizing compiler performing e.g. global inlining Targets exist for actionscript (alchemy) and javascript (emscripten) Cons: Actionscript target is closed source, unmaintained, and buggy. Javascript targets do not use features of HTML5 for appropriate optimization (e.g. linear memory with typed arrays) and are immature An LLVM target must convert from low-level bytecode, so high-level constructs are lost and bloated unreadable code is created from translating individual instructions, which may be more difficult for an unprepared JIT to optimize. "jump" instructions cause problems for languages with no "goto" statements. Using libclang to write a translator from C/C++ to web languages Pros: A beautiful parsing library providing easy access to the code structure Can code in C/C++ Has sponsored developer effort from Apple Cons: Incomplete; current feature set targets IDEs. Basic operators are unexposed and must be manually parsed from the returned AST element to be identified. Translating code prior to compilation may forgo optimizations assumed in c/c++ such as inlining. Creating new code generators for clang to translate into web languages Pros: Can code in C/C++ as libclang Cons: There is no API; code structure is unstable A much larger job than using libclang; the innards of clang are complex Building the game library in Common Lisp Pros: Flexible, ancient, well-developed language Extensive introspection should ease writing translators Translators exist for at least javascript Cons: Unfamiliar language No standardized library functions, widely varying implementations Which of these avenues should I pursue? Do you know of any others, or any systems that might be useful? Does a general project like this exist somewhere already? Thank you for any input.

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  • How safe is my safe rethrow?

    - by gustafc
    (Late edit: This question will hopefully be obsolete when Java 7 comes, because of the "final rethrow" feature which seems like it will be added.) Quite often, I find myself in situations looking like this: do some initialization try { do some work } catch any exception { undo initialization rethrow exception } In C# you can do it like this: InitializeStuff(); try { DoSomeWork(); } catch { UndoInitialize(); throw; } For Java, there's no good substitution, and since the proposal for improved exception handling was cut from Java 7, it looks like it'll take at best several years until we get something like it. Thus, I decided to roll my own: (Edit: Half a year later, final rethrow is back, or so it seems.) public final class Rethrow { private Rethrow() { throw new AssertionError("uninstantiable"); } /** Rethrows t if it is an unchecked exception. */ public static void unchecked(Throwable t) { if (t instanceof Error) throw (Error) t; if (t instanceof RuntimeException) throw (RuntimeException) t; } /** Rethrows t if it is an unchecked exception or an instance of E. */ public static <E extends Exception> void instanceOrUnchecked( Class<E> exceptionClass, Throwable t) throws E, Error, RuntimeException { Rethrow.unchecked(t); if (exceptionClass.isInstance(t)) throw exceptionClass.cast(t); } } Typical usage: public void doStuff() throws SomeException { initializeStuff(); try { doSomeWork(); } catch (Throwable t) { undoInitialize(); Rethrow.instanceOrUnchecked(SomeException.class, t); // We shouldn't get past the above line as only unchecked or // SomeException exceptions are thrown in the try block, but // we don't want to risk swallowing an error, so: throw new SomeException("Unexpected exception", t); } private void doSomeWork() throws SomeException { ... } } It's a bit wordy, catching Throwable is usually frowned upon, I'm not really happy at using reflection just to rethrow an exception, and I always feel a bit uneasy writing "this will not happen" comments, but in practice it works well (or seems to, at least). What I wonder is: Do I have any flaws in my rethrow helper methods? Some corner cases I've missed? (I know that the Throwable may have been caused by something so severe that my undoInitialize will fail, but that's OK.) Has someone already invented this? I looked at Commons Lang's ExceptionUtils but that does other things. Edit: finally is not the droid I'm looking for. I'm only interested to do stuff when an exception is thrown. Yes, I know catching Throwable is a big no-no, but I think it's the lesser evil here compared to having three catch clauses (for Error, RuntimeException and SomeException, respectively) with identical code. Note that I'm not trying to suppress any errors - the idea is that any exceptions thrown in the try block will continue to bubble up through the call stack as soon as I've rewinded a few things.

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  • gcc/g++: error when compiling large file

    - by Alexander
    Hi, I have a auto-generated C++ source file, around 40 MB in size. It largely consists of push_back commands for some vectors and string constants that shall be pushed. When I try to compile this file, g++ exits and says that it couldn't reserve enough virtual memory (around 3 GB). Googling this problem, I found that using the command line switches --param ggc-min-expand=0 --param ggc-min-heapsize=4096 may solve the problem. They, however, only seem to work when optimization is turned on. 1) Is this really the solution that I am looking for? 2) Or is there a faster, better (compiling takes ages with these options acitvated) way to do this? Best wishes, Alexander Update: Thanks for all the good ideas. I tried most of them. Using an array instead of several push_back() operations reduced memory usage, but as the file that I was trying to compile was so big, it still crashed, only later. In a way, this behaviour is really interesting, as there is not much to optimize in such a setting -- what does the GCC do behind the scenes that costs so much memory? (I compiled with deactivating all optimizations as well and got the same results) The solution that I switched to now is reading in the original data from a binary object file that I created from the original file using objcopy. This is what I originally did not want to do, because creating the data structures in a higher-level language (in this case Perl) was more convenient than having to do this in C++. However, getting this running under Win32 was more complicated than expected. objcopy seems to generate files in the ELF format, and it seems that some of the problems I had disappeared when I manually set the output format to pe-i386. The symbols in the object file are by standard named after the file name, e.g. converting the file inbuilt_training_data.bin would result in these two symbols: binary_inbuilt_training_data_bin_start and binary_inbuilt_training_data_bin_end. I found some tutorials on the web which claim that these symbols should be declared as extern char _binary_inbuilt_training_data_bin_start;, but this does not seem to be right -- only extern char binary_inbuilt_training_data_bin_start; worked for me.

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  • Hadoop in a RESTful Java Web Application - Conflicting URI templates

    - by user1231583
    I have a small Java Web Application in which I am using Jersey 1.12 and the Hadoop 1.0.0 JAR file (hadoop-core-1.0.0.jar). When I deploy my application to my JBoss 5.0 server, the log file records the following error: SEVERE: Conflicting URI templates. The URI template / for root resource class org.apache.hadoop.hdfs.server.namenode.web.resources.NamenodeWebHdfsMethods and the URI template / transform to the same regular expression (/.*)? To make sure my code is not the problem, I have created a fresh web application that contains nothing but the Jersey and Hadoop JAR files along with a small stub. My web.xml is as follows: <?xml version="1.0" encoding="UTF-8"?> <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <servlet> <servlet-name>ServletAdaptor</servlet-name> <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet- class> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>ServletAdaptor</servlet-name> <url-pattern>/mytest/*</url-pattern> </servlet-mapping> <session-config> <session-timeout> 30 </session-timeout> </session-config> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app> My simple RESTful stub is as follows: import javax.ws.rs.core.Context; import javax.ws.rs.core.UriInfo; import javax.ws.rs.Path; @Path("/mytest") public class MyRest { @Context private UriInfo context; public MyRest() { } } In my regular application, when I remove the Hadoop JAR files (and the code that is using Hadoop), everything works as I would expect. The deployment is successful and the remaining RESTful services work. I have also tried the Hadoop 1.0.1 JAR files and have had the same problems with the conflicting URL template in the NamenodeWebHdfsMethods class. Any suggestions or tips in solving this problem would be greatly appreciated.

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  • a question about rails general practice with REST, json, and ajax

    - by Nik
    Hi all, I have this question concerning REST I think: I have read a few rest tutorials and the feeling I get from them is that each action in a restful controller tends to be lean and almost single purpose: "Index gives off a collection of a model show gives off one model edit/new a prep place for changing/create a model update/create changes and makes new model deletes removes one model" After reading all these tutorials, rest seems to be to be a means to create an interface for a model, much like active resource type of thing. the mantra seems to be "controller provides data and data only and is also pretty convention over configuration, so expect projects_path to return a bunch of projects" I can understand that, and I like the cleanliness. But here's when I run into some trouble in reality in applying these guidelines: say three models, Project with attrib title, User with attrib name, and Location with attrib address. Say in views/users/index.html.erb, I want to use Ajax to fetch and display a project in a div#project_display when the user clicks on a project element, I know that I can use views/projects/show.js.rjs like this: page.replace_html 'project_display' "#{@project.name}" where in the projects_controller.rb def show @project = Project.find(params[:id]) repsond_to do |format| format.js and other formats... end end I have no problem in doing that for a couple of years now. BUT doesn't that mean that my JS response for the project#show action is LOCkED to present data to div#project_display element and show only whatever I that rjs template says it should show? That's very limiting and doesn't sound very "interface" like. I have never used JSON before or much XML, so I thought, maybe the JS response should send back raw stuff, like JSON and somehow the page on which the ajax request was called has the instruction on what do to with these raw data. That sounds a lot more flexible, doesn't it? Because look back at that exmpale, what if in the views/locations/index.html.erb, I want to do the exact same thing except I want to put the response in div#project_goes_here and the response should be #{project.name} I know this is a trivial change but that's the point: the RJS only allows one template at a time. So I think the JSON route is the way to go, but how does the already loaded page, the one that the ajax call came from, know when or how to "look forward" to incoming data? I read that PrototypeJS has this template thing, I wouldn't mind using it with JSON, but if you can demonstrate this or other means for displaying received-from-ajax data, I am all attention. Thank You

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  • deleted gen folder, eclipse isn't generating it now :(

    - by LuxuryMode
    I accidentally deleted my gen folder and now, predictably, my resources are all messed up. I just created a gen folder myself and tried to project clean - that didn't work. Tried right-clicking project and going to android tools fix project properties - didn't work. Tried unchecking build automatically...didn't work. cleaned, closed project, closed eclipse, restarted, etc, etc. Nothing is working and I keep seeing this error: gen already exists but is not a source folder. Convert to a source folder or rename it. EDIT - OK was able to generate R.java, but now I'm getting crazy stuff in the console: [2011-06-14 17:06:11 - fastapp] Conversion to Dalvik format failed with error 1 [2011-06-14 17:06:42 - fastapp] Dx trouble processing "java/awt/font/NumericShaper.class": Ill-advised or mistaken usage of a core class (java.* or javax.*) when not building a core library. This is often due to inadvertently including a core library file in your application's project, when using an IDE (such as Eclipse). If you are sure you're not intentionally defining a core class, then this is the most likely explanation of what's going on. However, you might actually be trying to define a class in a core namespace, the source of which you may have taken, for example, from a non-Android virtual machine project. This will most assuredly not work. At a minimum, it jeopardizes the compatibility of your app with future versions of the platform. It is also often of questionable legality. If you really intend to build a core library -- which is only appropriate as part of creating a full virtual machine distribution, as opposed to compiling an application -- then use the "--core-library" option to suppress this error message. If you go ahead and use "--core-library" but are in fact building an application, then be forewarned that your application will still fail to build or run, at some point. Please be prepared for angry customers who find, for example, that your application ceases to function once they upgrade their operating system. You will be to blame for this problem. If you are legitimately using some code that happens to be in a core package, then the easiest safe alternative you have is to repackage that code. That is, move the classes in question into your own package namespace. This means that they will never be in conflict with core system classes. JarJar is a tool that may help you in this endeavor. If you find that you cannot do this, then that is an indication that the path you are on will ultimately lead to pain, suffering, grief, and lamentation. [2011-06-14 17:06:42 - fastapp] Dx 1 error; aborting [2011-06-14 17:06:42 - fastapp] Conversion to Dalvik format failed with error 1 And eclipse can't resolve the import of my resources import com.me.fastapp.R;

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  • Help with Arrays in Objective C.

    - by NJTechie
    Problem : Take an integer as input and print out number equivalents of each number from input. I hacked my thoughts to work in this case but I know it is not an efficient solution. For instance : 110 Should give the following o/p : one one zero Could someone throw light on effective usage of Arrays for this problem? #import <Foundation/Foundation.h> int main (int argc, const char * argv[]) { NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; int input, i=0, j,k, checkit; int temp[i]; NSLog(@"Enter an integer :"); scanf("%d", &input); checkit = input; while(input > 0) { temp[i] = input%10; input = input/10; i++; } if(checkit != 0) { for(j=i-1;j>=0;j--) { //NSLog(@" %d", temp[j]); k = temp[j]; //NSLog(@" %d", k); switch (k) { case 0: NSLog(@"zero"); break; case 1: NSLog(@"one"); break; case 2: NSLog(@"two"); break; case 3: NSLog(@"three"); break; case 4: NSLog(@"four"); break; case 5: NSLog(@"five"); break; case 6: NSLog(@"six"); break; case 7: NSLog(@"seven"); break; case 8: NSLog(@"eight"); break; case 9: NSLog(@"nine"); break; default: break; } } } else NSLog(@"zero"); [pool drain]; return 0; }

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  • How to use Wordpress' http.php in external projects?

    - by NJTechGuy
    I am trying to parse data from a pipe-delimited text file hosted on another server which in turn will be inserted in a database. My host (1and1) disabled allow_url_fopen in php.ini I guess. Error message : Warning: fopen() [function.fopen]: URL file-access is disabled in the server configuration in Code : <? // make sure curl is installed if (function_exists('curl_init')) { // initialize a new curl resource $ch = curl_init(); // set the url to fetch curl_setopt($ch, CURLOPT_URL, 'http://abc.com/data/output.txt'); // don't give me the headers just the content curl_setopt($ch, CURLOPT_HEADER, 0); // return the value instead of printing the response to browser curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); // use a user agent to mimic a browser curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0'); $content = curl_exec($ch); // remember to always close the session and free all resources curl_close($ch); } else { // curl library is not installed so we better use something else } //$contents = fread ($fd,filesize ($filename)); //fclose ($fd); $delimiter = "|"; $splitcontents = explode($delimiter, $contents); $counter = ""; ?> <font color="blue" face="arial" size="4">Complete File Contents</font> <hr> <? echo $contents; ?> <br><br> <font color="blue" face="arial" size="4">Split File Contents</font> <hr> <? foreach ( $splitcontents as $color ) { $counter = $counter+1; echo "<b>Split $counter: </b> $colorn<br>"; } ?> Wordpress has this cool http.php file. Is there a better way of doing it? If not, how do I use http.php for this task? Thank you guys..

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  • Persistent (purely functional) Red-Black trees on disk performance

    - by Waneck
    I'm studying the best data structures to implement a simple open-source object temporal database, and currently I'm very fond of using Persistent Red-Black trees to do it. My main reasons for using persistent data structures is first of all to minimize the use of locks, so the database can be as parallel as possible. Also it will be easier to implement ACID transactions and even being able to abstract the database to work in parallel on a cluster of some kind. The great thing of this approach is that it makes possible implementing temporal databases almost for free. And this is something quite nice to have, specially for web and for data analysis (e.g. trends). All of this is very cool, but I'm a little suspicious about the overall performance of using a persistent data structure on disk. Even though there are some very fast disks available today, and all writes can be done asynchronously, so a response is always immediate, I don't want to build all application under a false premise, only to realize it isn't really a good way to do it. Here's my line of thought: - Since all writes are done asynchronously, and using a persistent data structure will enable not to invalidate the previous - and currently valid - structure, the write time isn't really a bottleneck. - There are some literature on structures like this that are exactly for disk usage. But it seems to me that these techniques will add more read overhead to achieve faster writes. But I think that exactly the opposite is preferable. Also many of these techniques really do end up with a multi-versioned trees, but they aren't strictly immutable, which is something very crucial to justify the persistent overhead. - I know there still will have to be some kind of locking when appending values to the database, and I also know there should be a good garbage collecting logic if not all versions are to be maintained (otherwise the file size will surely rise dramatically). Also a delta compression system could be thought about. - Of all search trees structures, I really think Red-Blacks are the most close to what I need, since they offer the least number of rotations. But there are some possible pitfalls along the way: - Asynchronous writes -could- affect applications that need the data in real time. But I don't think that is the case with web applications, most of the time. Also when real-time data is needed, another solutions could be devised, like a check-in/check-out system of specific data that will need to be worked on a more real-time manner. - Also they could lead to some commit conflicts, though I fail to think of a good example of when it could happen. Also commit conflicts can occur in normal RDBMS, if two threads are working with the same data, right? - The overhead of having an immutable interface like this will grow exponentially and everything is doomed to fail soon, so this all is a bad idea. Any thoughts? Thanks! edit: There seems to be a misunderstanding of what a persistent data structure is: http://en.wikipedia.org/wiki/Persistent_data_structure

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  • Getting Started with Maven + Jaxb project + IntellijIdea

    - by Em Ae
    I am complete new to IntellijIdea and i am looking for some step-by-step process to set up a basic project. My project depends on Maven + Jaxb classes so i need a Maven project so that when i compile this project, the JAXB Objects are generated by Maven plugins. Now i started like this I created a blank project say MaJa project Added Maven Module to it Added following settings in POM.XML <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>MaJa</groupId> <artifactId>MaJa</artifactId> <version>1.0</version> <dependencies> <dependency> <groupId>javax.xml.bind</groupId> <artifactId>jaxb-api</artifactId> </dependency> <dependency> <groupId>com.sun.xml.bind</groupId> <artifactId>jaxb-impl</artifactId> <version>2.1</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>jaxb2-maven-plugin</artifactId> <executions> <execution> <goals> <goal>xjc</goal> </goals> </execution> </executions> <configuration> <schemaDirectory>${basedir}/src/main/resource/api/MaJa</schemaDirectory> <packageName>com.rimt.shopping.api.web.ws.v1.model</packageName> <outputDirectory>${build.directory}</outputDirectory> </configuration> </plugin> </plugins> </build> </project> First of all, is it right settings ? I tried clicking on Make/Compile 'MaJa' from Project Right Click Menu and it didn't do anything. I will be looking forward to yoru replies.

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  • Stuck on an ASP.NET/WCF WSDL Parsing Error

    - by Vaccano
    I have a WCF Web Service that my ASP.NET app uses. It has been working fine for quite some time. I just added in a Dev Express Grid (and the Dev Express DLLs) and a new page that uses them and now I am getting parsing errors on the WSDL. But the weird part is that it works fine on my machine but fails on the web server machine. (Both are connecting to the same web services WSDL.) Here is the error message I am getting: Server Error in '/MyWebAppWebDev' Application. -------------------------------------------------------------------------------- Parser Error Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately. Parser Error Message: Reference.svcmap: Failed to generate code for the service reference 'MyWebAppService'. Cannot import wsdl:portType Detail: An exception was thrown while running a WSDL import extension: System.ServiceModel.Description.DataContractSerializerMessageContractImporter Error: Referenced type 'WebClientApp.MyWebAppService.ReferenceUpdatesDataContract, WebClientApp, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' with data contract name 'ReferenceUpdatesDataContract' in namespace 'http://schemas.datacontract.org/2004/07/MyWebAppServiceLibrary.DataContracts' cannot be used since it does not match imported DataContract. Need to exclude this type from referenced types. XPath to Error Source: //wsdl:definitions[@targetNamespace='http://tempuri.org/']/wsdl:portType[@name='IMyWebAppReferenceDataServiceLib'] Cannot import wsdl:binding Detail: There was an error importing a wsdl:portType that the wsdl:binding is dependent on. XPath to wsdl:portType: //wsdl:definitions[@targetNamespace='http://tempuri.org/']/wsdl:portType[@name='IMyWebAppReferenceDataServiceLib'] XPath to Error Source: //wsdl:definitions[@targetNamespace='http://tempuri.org/']/wsdl:binding[@name='MyWebAppServicesDefaultEndpoint'] Cannot import wsdl:port Detail: There was an error importing a wsdl:binding that the wsdl:port is dependent on. XPath to wsdl:binding: //wsdl:definitions[@targetNamespace='http://tempuri.org/']/wsdl:binding[@name='MyWebAppServicesDefaultEndpoint'] XPath to Error Source: //wsdl:definitions[@targetNamespace='http://tempuri.org/']/wsdl:service[@name='MyWebAppReferenceDataServiceLib']/wsdl:port[@name='MyWebAppServicesDefaultEndpoint'] Source Error: [No relevant source lines] Source File: /MyWebAppWebDev/App_WebReferences/MyWebAppService/ Line: 1 I am completely stumped on this. I have checked my web.config endpoint address and it is spot on (and notably is not in the error message above). Any ideas would be welcomed. Things I have tried: Giving permissions to C:\Windows\temp to my Website user name Giving permissions to C:\Windows\temp to my App pool user name Checking to see that none of my data contracts are generic and have IsReference=true in them.

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  • Performance tuning of a Hibernate+Spring+MySQL project operation that stores images uploaded by user

    - by Umar
    Hi I am working on a web project that is Spring+Hibernate+MySQL based. I am stuck at a point where I have to store images uploaded by a user into the database. Although I have written some code that works well for now, but I believe that things will mess up when the project would go live. Here's my domain class that carries the image bytes: @Entity public class Picture implements java.io.Serializable{ long id; byte[] data; ... // getters and setters } And here's my controller that saves the file on submit: public class PictureUploadFormController extends AbstractBaseFormController{ ... protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception{ MutlipartFile file; // getting MultipartFile from the command object ... // beginning hibernate transaction ... Picture p=new Picture(); p.setData(file.getBytes()); pictureDAO.makePersistent(p); // this method simply calls getSession().saveOrUpdate(p) // committing hiernate transaction ... } ... } Obviously a bad piece of code. Is there anyway I could use InputStream or Blob to save the data, instead of first loading all the bytes from the user into the memory and then pushing them into the database? I did some research on hibernate's support for Blob, and found this in Hibernate In Action book: java.sql.Blob and java.sql.Clob are the most efficient way to handle large objects in Java. Unfortunately, an instance of Blob or Clob is only useable until the JDBC transaction completes. So if your persistent class defines a property of java.sql.Clob or java.sql.Blob (not a good idea anyway), you’ll be restricted in how instances of the class may be used. In particular, you won’t be able to use instances of that class as detached objects. Furthermore, many JDBC drivers don’t feature working support for java.sql.Blob and java.sql.Clob. Therefore, it makes more sense to map large objects using the binary or text mapping type, assuming retrieval of the entire large object into memory isn’t a performance killer. Note you can find up-to-date design patterns and tips for large object usage on the Hibernate website, with tricks for particular platforms. Now apparently the Blob cannot be used, as it is not a good idea anyway, what else could be used to improve the performance? I couldn't find any up-to-date design pattern or any useful information on Hibernate website. So any help/recommendations from stackoverflowers will be much appreciated. Thanks

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  • How to maxmise the largest contiguous block of memory in the Large Object Heap

    - by Unsliced
    The situation is that I am making a WCF call to a remote server which is returns an XML document as a string. Most of the time this return value is a few K, sometimes a few dozen K, very occasionally a few hundred K, but very rarely it could be several megabytes (first problem is that there is no way for me to know). It's these rare occasions that are causing grief. I get a stack trace that starts: System.OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown. at System.Xml.BufferBuilder.AddBuffer() at System.Xml.BufferBuilder.AppendHelper(Char* pSource, Int32 count) at System.Xml.BufferBuilder.Append(Char[] value, Int32 start, Int32 count) at System.Xml.XmlTextReaderImpl.ParseText() at System.Xml.XmlTextReaderImpl.ParseElementContent() at System.Xml.XmlTextReaderImpl.Read() at System.Xml.XmlTextReader.Read() at System.Xml.XmlReader.ReadElementString() at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReaderMDRQuery.Read2_getMarketDataResponse() at Microsoft.Xml.Serialization.GeneratedAssembly.ArrayOfObjectSerializer2.Deserialize(XmlSerializationReader reader) at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle, XmlDeserializationEvents events) at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle) at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) I've read around and it is because the Large Object Heap is just getting too fragmented, so even preceding the call with a quick check to StringBuilder.EnsureCapacity just causes the OutOfMemoryException to be thrown earlier (and because I'm guessing at what's needed, it might not actually need that much so my check is causing more problems than it is solving). Some opinions are that there's not much I can do about it. Some of the questions I've asked myself: Use less memory - have you checked for leaks? Yes. The memory usage goes up and down, but there's no fundamental growth that guarantees this to happen. Some of the times it fails, it succeeded at that stage previously. Transfer smaller amounts Not an option, this is a third party web service over which I have no control (or at least it would take a long time to resolve, in the meantime I still have a problem) Can you do something to the LOH to make it less likely to fail? ... now this is most fruitful course. It's a 32-bit process (it has to be for various political, technical and boring reasons) but there's normally hundreds of meg free (multiples of the largest amount for which we've seen failures). Can we monitor the LOH? Using perfmon I can track the size of the heaps, but I don't think there's a way to monitor the largest available contiguous block of memory. Question is: any advice or suggestions for things to try?

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  • What are the Options for Storing Hierarchical Data in a Relational Database?

    - by orangepips
    Good Overviews One more Nested Intervals vs. Adjacency List comparison: the best comparison of Adjacency List, Materialized Path, Nested Set and Nested Interval I've found. Models for hierarchical data: slides with good explanations of tradeoffs and example usage Representing hierarchies in MySQL: very good overview of Nested Set in particular Hierarchical data in RDBMSs: most comprehensive and well organized set of links I've seen, but not much in the way on explanation Options Ones I am aware of and general features: Adjacency List: Columns: ID, ParentID Easy to implement. Cheap node moves, inserts, and deletes. Expensive to find level (can store as a computed column), ancestry & descendants (Bridge Hierarchy combined with level column can solve), path (Lineage Column can solve). Use Common Table Expressions in those databases that support them to traverse. Nested Set (a.k.a Modified Preorder Tree Traversal) First described by Joe Celko - covered in depth in his book Trees and Hierarchies in SQL for Smarties Columns: Left, Right Cheap level, ancestry, descendants Compared to Adjacency List, moves, inserts, deletes more expensive. Requires a specific sort order (e.g. created). So sorting all descendants in a different order requires additional work. Nested Intervals Combination of Nested Sets and Materialized Path where left/right columns are floating point decimals instead of integers and encode the path information. Bridge Table (a.k.a. Closure Table: some good ideas about how to use triggers for maintaining this approach) Columns: ancestor, descendant Stands apart from table it describes. Can include some nodes in more than one hierarchy. Cheap ancestry and descendants (albeit not in what order) For complete knowledge of a hierarchy needs to be combined with another option. Flat Table A modification of the Adjacency List that adds a Level and Rank (e.g. ordering) column to each record. Expensive move and delete Cheap ancestry and descendants Good Use: threaded discussion - forums / blog comments Lineage Column (a.k.a. Materialized Path, Path Enumeration) Column: lineage (e.g. /parent/child/grandchild/etc...) Limit to how deep the hierarchy can be. Descendants cheap (e.g. LEFT(lineage, #) = '/enumerated/path') Ancestry tricky (database specific queries) Database Specific Notes MySQL Use session variables for Adjacency List Oracle Use CONNECT BY to traverse Adjacency Lists PostgreSQL ltree datatype for Materialized Path SQL Server General summary 2008 offers HierarchyId data type appears to help with Lineage Column approach and expand the depth that can be represented.

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