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• MissingMethodException thrown when calling new form in Compact Framework

  - by Boerema

  I'm updating an old mobile device application for better flexibility. I had basically added the ability to configure the address of our SQL server in the case that we want to use our test server as opposed to our production server. I don't think this is causing the problem, but I wanted to state it. I also upgraded the project from a VS 2000 project to a VS 2005 project. The issue I am having is that when I try to run the program in the VS emulator for Pocket PC, I get an error. It occurs after our "main menu" form loads and the user selects the next form to load. The form is initialized without issue, but when we try to run the .ShowDialog() method, it throws a System.MissingMethodException. I don't have a lot of experience with the Compact Framework and really have no idea where to start looking for problems. I stepped the debugger through the entire initializing process for the new form and it ran without issue. But, again, when we come to the ShowDialog call, it throws the error. Any ideas in where to start looking or known issues would be greatly appreciated.

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• Convert function to read from string instead of file in C

  - by Dusty

  I've been tasked with updating a function which currently reads in a configuration file from disk and populates a structure: static int LoadFromFile(FILE *Stream, ConfigStructure *cs) { int tempInt; ... if ( fscanf( Stream, "Version: %d\n",&tempInt) != 1 ) { printf("Unable to read version number\n"); return 0; } cs->Version = tempInt; ... } to one which allows us to bypass writing the configuration to disk and instead pass it directly in memory, roughly equivalent to this: static int LoadFromString(char *Stream, ConfigStructure *cs) A few things to note: The current LoadFromFile function is incredibly dense and complex, reading dozens of versions of the config file in a backward compatible manner, which makes duplication of the overall logic quite a pain. The functions that generate the config file and those that read it originate in totally different parts of the old system and therefore don't share any data structures so I can't pass those directly. I could potentially write a wrapper, but again, it would need to handle any structure passed in in a backwards compatible manner. I'm tempted to just pass the file as is in as a string (as in the prototype above) and convert all the fscanf's to sscanf's but then I have to handle incrementing the pointer along (and potentially dealing with buffer overrun errors) manually. This has to remain in C, so no C++ functionality like streams can help here Am I missing a better option? Is there some way to create a FILE * that actually just points to a location in memory instead of on disk? Any pointers, suggestions or other help is greatly appreciated.

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• Generating equals / hashcode / toString using annotation

  - by Bruno Bieth

  I believe I read somewhere people generating equals / hashcode / toString methods during compile time (using APT) by identifying which fields should be part of the hash / equality test. I couldn't find anything like that on the web (I might have dreamed it ?) ... That could be done like that : public class Person { @Id @GeneratedValue private Integer id; @Identity private String firstName, lastName; @Identity private Date dateOfBirth; //... } For an entity (so we want to exlude some fields, like the id). Or like a scala case class i.e a value object : @ValueObject public class Color { private int red, green, blue; } Not only the file becomes more readable and easier to write, but it also helps ensuring that all the attributes are part of the equals / hashcode (in case you add another attribute later on, without updating the methods accordingly). I heard APT isn't very well supported in IDE but I wouldn't see that as a major issue. After all, tests are mainly run by continuous integration servers. Any idea if this has been done already and if not why ? Thanks

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• PostgreSQL - Why are some queries on large datasets so incredibly slow

  - by Brad Mathews

  Hello, I have two types of queries I run often on two large datasets. They run much slower than I would expect them to. The first type is a sequential scan updating all records: Update rcra_sites Set street = regexp_replace(street,'/','','i') rcra_sites has 700,000 records. It takes 22 minutes from pgAdmin! I wrote a vb.net function that loops through each record and sends an update query for each record (yes, 700,000 update queries!) and it runs in less than half the time. Hmmm.... The second type is a simple update with a relation and then a sequential scan: Update rcra_sites as sites Set violations='No' From narcra_monitoring as v Where sites.agencyid=v.agencyid and v.found_violation_flag='N' narcra_monitoring has 1,700,000 records. This takes 8 minutes. The query planner refuses to use my indexes. The query runs much faster if I start with a set enable_seqscan = false;. I would prefer if the query planner would do its job. I have appropriate indexes, I have vacuumed and analyzed. I optimized my shared_buffers and effective_cache_size best I know to use more memory since I have 4GB. My hardware is pretty darn good. I am running v8.4 on Windows 7. Is PostgreSQL just this slow? Or am I still missing something? Thanks! Brad

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• Application design in Spring MVC

  - by Ravi

  Hello All, I'm new to Spring MVC and trying out a simple project.It will contain a simple adding, viewing, updating and deleting user work flows. It will have login page and once authenticated the user will be taken to a welcome screen which will have links to add, view, update and delete users. Clicking on any of the links will take to individual pages where the user can do the specific tasks. What I'm doing here is, I'm using a MultiActionController to group together all requests related to User work flow. So the request from "Add User" link will handled by the addUser method in the UserController which will redirect the user to the "Add User" page, and the user can then fill in the details and save the new user. Now here is where I'm getting confused. Where should I put the save process of the new user, should I put that in new mehtod inside UserController, or use the same "addUser" method. What is the best way to handle this kind of scenario. I hope I was able to clear my question.

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• Can someone describe the nested set model from a C#/LINQ perspective?

  - by Chad

  I know the nested set model doesn't pertain to the C# language or LINQ directly... it's what I'm using to develop my web app. For hierarchical data (categories with sub-categories in my case), I'm currently using something similar to the Adjacency List model. At the moment, I've only got 2 levels of categories, but I'd like to take it further and allow for n levels of categories using the nested set model. I'm not quite clear on how to use it in a C# context. Here's the article I'm reading on the nested set model. Though this article cleared up my confusion some, I still have a big ?? in my head: - Is inserting, updating or deleting categories tedious? It looks like the left and right numbers would require re-numbering... what would the LINQ queries look like for the following scenarios? Delete a child node (re-number all node's left/right values) Delete a parent node (what do you do with the orphans?) Move a child node to a different parent node (renumber again) If my understanding is correct, at all times the child node's left/right values will always be between the parent node's left/right values, am I correct? Seems easy enough, if only the categories were static... most likely I need to spend more time to get my head around the concept. Any help is greatly appreciated!

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• Software Update Notifications

  - by devio

  I am considering implementing some sort of Software Update Notification for one of the web applications I am developing. There are several questions I came across: Should the update check be executed on the client or on the server? Client-side means, the software retrieves the most current version information, performs its checks, and displays the update information. Server-side check means the software sends its version info to the server, which in turn does the calculations and returns information to the client. My guess is that server-side implementation may turn out to be more flexible and more powerful than client-side, as I can add functionality to the server easily, as long as the client understands it. Where should the update info be displayed? Is it ok to display on the login screen? Should only admins see it? (this is a web app with a database, so updating requires manipulation of db and web, which is only done by admins). What about a little beeping flashing icon which increases in size as the version gets more obsolete every day ;) ? Privacy issues Not everybody likes to have their app usage stats broadcast over the internet. TheOnion question: What do you think?

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• How do you find a functions virtual call address in assembly?

  - by Daniel

  I've googled around but i'm not sure i am asking the right question or not and i couldn't find much regardless, perhaps a link would be helpful. I made a c++ program that shows a message box, then I opened it up with Ollydbg and went to the part where it calls MessageBoxW. The call address of MessageBoxW changes each time i run the app as windows is updating my Imports table to have the correct address of MessageBoxW. So my question is how do i find the virtual addres of MessageBoxW to my imports table and also how can i use this in ollydbg? Basically I'm trying to make a code cave in assembly to call MessageBoxW again. I got fairly close once by searching the executable with a hex editor and found the position of the call, and I think I found the virtual address. But when i call that virtual address in olly and saved it to the executable, the next time i opened it the call was replaced with a bunch of DB xyz (which looked like the virtual address but why did the call get removed? Sorry if my terminology is off as i'm new to this so i'm not quite sure what to call things.

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• How to force an HTML JLabel in a JTree to resize when the font changes

  - by Mike

  I'm updating a Java Swing application to support the user switching the app's font from normal size to a larger size (so the user can switch between the two sizes at runtime). One problem I'm having is with a JTree that uses HTML for the tree nodes to underline the text in some nodes (the HTML is just embedded in the JLabel of each tree node). One extra thing to know about the nodes is that they're a custom component, adding a JCheckBox in front of each JLabel. The problem is that once the JTree is visible, increasing the font size causes the nodes (containing underlined text) to not resize. The HTML for those nodes seems to prevent the node from becoming wider, so when the font changes, the text becomes truncated. I think my options are to either: 1) use another approach to make the text underlined, since removing the HTML from the JLabel causes it to resize properly when the font size changes, or 2) keep the HTML formatting and somehow force the JTree/JLabels to resize when the font size is updated (possibly by firing a property change event?). The code already calls SwingUtilities.updateComponentTreeUI() on the parent JFrame when the font size gets updated. Any help would be greatly appreciated. Thanks in advance! -Mike

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• iPhone programming - problem with CoreFoundation forking

  - by Tom

  Hello all, I've been working on an iPhone for several months. It's a 2d shooting game akin to the old Smash TV type games. I'm doing everything alone and it has come out well so far, but now I am getting unpredictable crashes which seem to be related to CoreFoundation forking and not exec()ing, as the message __THE_PROCESS_HAS_FORKED_AND_YOU_CANNOT_USE_THIS_COREFOUNDATION_FUNCTIONA LITY___YOU_MUST_EXEC__ always shows up somewhere in the debugger. Usually it shows up around a CFRunLoopRunSpecific and is related to either a timer firing or _InitializeTouchTapCount. I cannot figure out exactly what is causing the fork to occur. My main game loop is running on a timer, first updating all the logic and then drawing everything with openGL. There is nothing highly complex or unusual. I understand you cannot make CF calls on the childside of a fork, or access shared memory and things like that. I am not explicitly trying to fork anything. My question is: can anyone tell me what type of activity might cause CoreFoundation to randomly fork like this? I'd really like to finish this game and I don't know how to solve this problem. Thanks for any help.

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• OpenGL ES, UIView and Status Bar mess

  - by sfider

  I have iPhone (iPhoneOS 3.x) OpenGL ES app that: can be in landscape/portrait orientation can be with/without status bar shown I do this by changing status bar orientation and hidden state, then updating OpenGL view frame so it won't overlap status bar and setting projection matrix appropriately. OpenGL view is in portrait orientation at all time. View controller's shouldAutorotateToInterfaceOrientation: method returns false always, so the status bar won't start autorotating when app is in landscape mode. The problem I have is that I want to use some other UIViews, like: UIWebView, MFMailComposeView, MPMediaPicker. I could show them as modals, but this this have some drawbacks: views will always show in portrait orientation, even if they support landscape orientation views will not autorotate, even if they support it What I do is I take OpenGL view of the window with removeFromSuperview, set transform to the other view so it will be in portrait/landscape orientation when it shows up and place the other view on the window with addSubview:. This works fine without the status bar, but with it there are some problems I cannot work out: MPMediaPicker is sized to fit under status bar, but it slides under it anyway MFMailComposeView does not show navigation bar until it autorotates on device orientation change Does anyone has an idea how can I get it to work?

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• manipulating textbox value

  - by chameios

  hello All, I am new to the programming world of dojo and web applications. I am trying to acomplish a task where I want to manipulate the textbox value with some text. I tried everything including some code from dojocampus, but even this code doesnot do anything. I have also tried to create an instance , with dojo.widget.byId and dijit.byId and then tried the instance.value = 'newtext' and everything that I could find but for some reason , the textbox is not updating. Please help me. <html> <head> <title>Dojo example</title> <style type="text/css"> @import "pathtodojo/dijit/themes/nihilo/nihilo.css"; </style> <style type="text/css"> </style> <script type="text/javascript" src="pathtodojo/dojo/dojo.js" djConfig="parseOnLoad:true, isDebug: true"></script> <script> dojo.require("dijit.form.TextBox"); function init() { var box0 = dijit.byId("value0Box"); var box1 = dijit.byId("value1Box"); box1.attr("value", box0.attr("value") + " modified"); dojo.connect(box0, "onChange", function(){ box1.attr("value", box0.attr("value") + " modified"); }); } dojo.addOnLoad(init); </script> <body class="nihilo"> A textbox with a value: <input id="value0Box" dojoType="dijit.form.TextBox" value="Some value" intermediateChanges="true"></input> <br> A textbox set with a value from the above textbox: <input id="value1Box" dojoType="dijit.form.TextBox"></input> <br> </body> </html> regards C

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• Problem with Binding Multiple Objects on WPF

  - by Diego Modolo Ribeiro

  Hi, I'm developing a user control called SearchBox, that will act as a replacer for ComboBox for multiple records, as the performance in ComboBox is low for this scenario, but I'm having a big binding problem. I have a base control with a DependencyProperty called SelectedItem, and my SearchControl shows that control so that the user can select the record. The SearchControl also has a DependencyProperty called SelectedItem on it, and it is being updated when the user selects something on the base control, but the UI, wich has the SearchControl, is not being updated. I used a null converter so that I could see if the property was updating, but it's not. Below is some of the code: This is the UI: <NectarControles:MaskedSearchControl x:Name="teste" Grid.Row="0" Grid.Column="1" Height="21" ItemsSource="{Binding C001_Lista}" DisplayMember="C001_Codigo" Custom:CustomizadorTextBox.CodigoCampo="C001_Codigo" ViewType="{x:Type C001:C001_Search}" ViewModelType="{x:Type C001_ViewModel:C001_ViewModel}" SelectedItem="{Binding Path=Instancia.C001_Holding, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource DebuggingConverter}}"> </NectarControles:MaskedSearchControl> This is the relevante part of the SearchControl: Binding selectedItemBinding = new Binding("SelectedItem"); selectedItemBinding.Source = this.SearchControlBase; selectedItemBinding.Mode = BindingMode.TwoWay; selectedItemBinding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged; this.SetBinding(SelectedItemProperty, selectedItemBinding); ... public System.Data.Objects.DataClasses.IEntityWithKey SelectedItem { get { return (System.Data.Objects.DataClasses.IEntityWithKey)GetValue(SelectedItemProperty); } set { SetValue(SelectedItemProperty, value); if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("SelectedItem")); } } Please someone help me... Tks...

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• Update panel and usercontrols

  - by Charlie Brown

  I have two web user controls nested inside of an update panel. The events inside the user controls do not appear to trigger the panel. For testing, I have set the method the fires to sleep for 3 seconds, and added an update progress panel to the page. The update progress panel never comes up and the page reflashes as usual. The user controls work correctly and do what they need to do, but I would like to make them ajaxy and pretty. Is there a special method for adding usercontrols to an update so the postback works correctly? <asp:ScriptManager ID="ScriptManager1" runat="server"> </asp:ScriptManager> <asp:UpdateProgress ID="UpdateProgress1" runat="server" DisplayAfter="100"> <ProgressTemplate> UPDATING...</ProgressTemplate> </asp:UpdateProgress> <asp:UpdatePanel ID="UpdatePanel1" runat="server"> <ContentTemplate> <div id="order"> <keg:BeerList runat="server" ID="uxBeerList" /> <kegcart:ShoppingCart runat="server" ID="uxCustomerCart" /> <br class="clearfloat" /> </div> </ContentTemplate> </asp:UpdatePanel> Protected Sub uxBeerList_AddItem(ByVal item As KegData.IOrderableItem) Handles uxBeerList.AddItem uxCustomerCart.AddItemToOrder(item) System.Threading.Thread.Sleep(5000) End Sub

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• parameter for xcodebuild for using latest sdk.

  - by Maciek Sawicki

  I using ant exec task to execute xcodebuild to build some iOS projects hudson. I would like to be able to crate script that way that allows not to specify sdk version, because after updating sdk on hudson slave or my iOS projects all my projects failing.... There is is nice option in xcode since sdk 4.2 in target setup Base SDK - Latest iOS and I don't have to provide -sdk param in xcodebuild command, but then (i think) it's taken from xcode project and it's bad because then some one can change target from simulator to device accidentally during commit. I need something that is constant. I will prefer not to use env variable because I would like to be able to run this ant task also on dev machines and would like not have to renember about setting it on all machines. Unfortunately xcodebuild -showsdk gives only: Mac OS X SDKs: Mac OS X 10.4 -sdk macosx10.4 Mac OS X 10.5 -sdk macosx10.5 Mac OS X 10.6 -sdk macosx10.6 iOS SDKs: iOS 4.2 -sdk iphoneos4.2 iOS Simulator SDKs: Simulator - iOS 3.2 -sdk iphonesimulator3.2 Simulator - iOS 4.0 -sdk iphonesimulator4.0 Simulator - iOS 4.1 -sdk iphonesimulator4.1 Simulator - iOS 4.2 -sdk iphonesimulator4.2 I need something like -sdk iphoneosLatest. My only idea is to pare output of xcodebuild -showsdk with some script, but I don't like this idea.

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• Updated MVC 4 to 5.2.0 via Nuget Site compiles but wont run

  - by hjavaher

  I had the bright idea of updating my perfectly working ASP.Net MVC 4 application to the MVC 5 via nuget, Everything compiles just fine but when I try to run the application I get the following yellow screen of death. Has anyone gotten this or know how to solve it? I've searched for it and couldn't find any solutions. Please let me know if there is any farther information that would help you that I can give you. Attempt by security transparent method 'WebMatrix.WebData.PreApplicationStartCode.Start()' to access security critical method 'System.Web.WebPages.Razor.WebPageRazorHost.AddGlobalImport(System.String)' failed. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.MethodAccessException: Attempt by security transparent method 'WebMatrix.WebData.PreApplicationStartCode.Start()' to access security critical method 'System.Web.WebPages.Razor.WebPageRazorHost.AddGlobalImport(System.String)' failed. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [MethodAccessException: Attempt by security transparent method 'WebMatrix.WebData.PreApplicationStartCode.Start()' to access security critical method 'System.Web.WebPages.Razor.WebPageRazorHost.AddGlobalImport(System.String)' failed.] WebMatrix.WebData.PreApplicationStartCode.Start() +112 [InvalidOperationException: The pre-application start initialization method Start on type WebMatrix.WebData.PreApplicationStartCode threw an exception with the following error message: Attempt by security transparent method 'WebMatrix.WebData.PreApplicationStartCode.Start()' to access security critical method 'System.Web.WebPages.Razor.WebPageRazorHost.AddGlobalImport(System.String)' failed..] System.Web.Compilation.BuildManager.InvokePreStartInitMethodsCore(ICollection`1 methods, Func`1 setHostingEnvironmentCultures) +556 System.Web.Compilation.BuildManager.InvokePreStartInitMethods(ICollection`1 methods) +132 System.Web.Compilation.BuildManager.CallPreStartInitMethods(String preStartInitListPath, Boolean& isRefAssemblyLoaded) +102 System.Web.Compilation.BuildManager.ExecutePreAppStart() +153 System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +516 [HttpException (0x80004005): The pre-application start initialization method Start on type WebMatrix.WebData.PreApplicationStartCode threw an exception with the following error message: Attempt by security transparent method 'WebMatrix.WebData.PreApplicationStartCode.Start()' to access security critical method 'System.Web.WebPages.Razor.WebPageRazorHost.AddGlobalImport(System.String)' failed..] System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +9885060 System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +101 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +254

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• Doing large updates against indexed view

  - by user217136

  We have an indexed view that runs across three large tables. Two of these tables (A & B) are constantly getting updated with user transactions and the other table (C) contains data product info that is needs to be updated once a week. This product table contains over 6 million records. We need this view across these three tables for our core business process and unfortunately we cannot change this aspect. We even had a sql server MVP come in to help test under load to make sure we have the most efficient configuration. There is one column in the product table that gets utilized in the view and has to be updated each week. The problem we are now encountering is that as volume is increasing on our transactions against tables A & B, the update to Table C is causing deadlocks. I have tried several different methods to no avail: 1) I was hoping that we could change the view so that table C could be a dirty read "WITH (NOLOCK)" but apparently that functionality is not available with indexes views. 2) I thought about updating a new column in Table C and then just renaming it when the process is done but you cannot do that due to the dependency in the view. 3) I also entertained the idea of writing this value to a temporary product table, and then running an ALTER statement against the view to have it point to my new table. however when i did that the indexes on my view were dropped and it took quite a bit of time to recreate them. 4) we tried to do the weekly update in small chunks (as small as 100 records at a time) but we still run into dead locks. questions: a) we are using sql server 2005. Does sql server 2008 have a new functionality with their indexed views that would help us? Is there now a way to do dirty reads w/ an indexed view? b) a better approach to altering an existing view to point to a new table? thanks!

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• How best to use XPath with very large XML files in .NET?

  - by glenatron

  I need to do some processing on fairly large XML files ( large here being potentially upwards of a gigabyte ) in C# including performing some complex xpath queries. The problem I have is that the standard way I would normally do this through the System.XML libraries likes to load the whole file into memory before it does anything with it, which can cause memory problems with files of this size. I don't need to be updating the files at all just reading them and querying the data contained in them. Some of the XPath queries are quite involved and go across several levels of parent-child type relationship - I'm not sure whether this will affect the ability to use a stream reader rather than loading the data into memory as a block. One way I can see of making it work is to perform the simple analysis using a stream-based approach and perhaps wrapping the XPath statements into XSLT transformations that I could run across the files afterward, although it seems a little convoluted. Alternately I know that there are some elements that the XPath queries will not run across, so I guess I could break the document up into a series of smaller fragments based on it's original tree structure, which could perhaps be small enough to process in memory without causing too much havoc. I've tried to explain my objective here so if I'm barking up totally the wrong tree in terms of general approach I'm sure you folks can set me right...

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• Rails : fighting long http response times with ajax. Is it a good idea? Please, help with implementa

  - by baranov

  Hi, everybody! I've googled some tutorials, browsed some SO answers, and was unable to find a recipe for my problem. I'm writing a web site which is supposed to display almost realtime stock chart. Data is stored in constantly updating MySQL database, I wrote a find_by_sql query code which fetches all the data I need to get my chart drawn. Everything is ok, except performance - it takes from one second to one minute for different queries to fetch all the data from the database, this time includes necessary (My)SQL-server side calculations. This is simply unacceptable. I got the following idea: if the data is queried from the MySQL server one point a time instead of entire dataset, it takes only about 1-100ms to get an individual point. I imagine the data fetch process might be browser-driven. After the user presses the button in order to get a chart drawn, controller makes one request to the database and renders, say, a progress bar, say 1% ready. When the browser gets the response, it immediately makes an (ajax) request, and the server fetches the next piece of data and renders "2%". And so on, until all the data is ready and the server displays the requested chart. Could this be implemented in rails+js, is there a tutorial for solving a similar problem on the Web? I suppose if the thing is feasible at all, somebody should have already done this before. I have read several articles about ajax, I believe I do understand general principles, but never did nontrivial ajax programming myself. Thanks for your time!

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• Documentation for java.util.concurrent.locks.ReentrantReadWriteLock

  - by Andrei Taptunov

  Disclaimer: I'm not very good at Java and just comparing read/writer locks between C# and Java to understand this topic better & decisions behind both implementations. There is JavaDoc about ReentrantReadWriteLock. It states the following about upgrade/downgrade for locks: Lock downgrading ... However, upgrading from a read lock to the write lock is not possible. It also has the following example that shows manual upgrade from read lock to write lock: // Here is a code sketch showing how to exploit reentrancy // to perform lock downgrading after updating a cache void processCachedData() { rwl.readLock().lock(); if (!cacheValid) { // upgrade lock manually #1: rwl.readLock().unlock(); // must unlock first to obtain writelock #2: rwl.writeLock().lock(); if (!cacheValid) { // recheck ... } ... } use(data); rwl.readLock().unlock(); Does it mean that actually the sample from above may not behave correctly in some cases - I mean there is no lock between lines #1 & #2 and underlying structure is exposed to changes from other threads. So it can not be considered as the correct way to upgrade the lock or do I miss something here?

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• Make seems to think a prerequisite is an intermediate file, removes it

  - by James

  For starters, this exercise in GNU make was admittedly just that: an exercise rather than a practicality, since a simple bash script would have sufficed. However, it brought up interesting behavior I don't quite understand. I've written a seemingly simple Makefile to handle generation of SSL key/cert pairs as necessary for MySQL. My goal was for make <name> to result in <name>-key.pem, <name>-cert.pem, and any other necessary files (specifically, the CA pair if any of it is missing or needs updating, which leads into another interesting follow-up exercise of handling reverse deps to reissue any certs that had been signed by a missing/updated CA cert). After executing all rules as expected, make seems to be too aggressive at identifying intermediate files for removal; it removes a file I thought would be "safe" since it should have been generated as a prereq to the main rule I'm invoking. (Humbly translated, I likely have misinterpreted make's documented behavior to suit my expectation, but don't understand how. ;-) Edited (thanks, Chris!) Adding %-cert.pem to .PRECIOUS does, of course, prevent the deletion. (I had been using the wrong syntax.) Makefile: OPENSSL = /usr/bin/openssl # Corrected, thanks Chris! .PHONY: clean default: ca clean: rm -I *.pem %: %-key.pem %-cert.pem @# Placeholder (to make this implicit create a rule and not cancel one) Makefile: @# Prevent the catch-all from matching Makefile ca-cert.pem: ca-key.pem $(OPENSSL) req -new -x509 -nodes -days 1000 -key ca-key.pem $@ %-key.pem: $(OPENSSL) genrsa 2048 $@ %-cert.pem: %-csr.pem ca-cert.pem ca-key.pem $(OPENSSL) x509 -req -in $ $@ Output: $ make host1 /usr/bin/openssl genrsa 2048 ca-key.pem /usr/bin/openssl req -new -x509 -nodes -days 1000 -key ca-key.pem ca-cert.pem /usr/bin/openssl genrsa 2048 host1-key.pem /usr/bin/openssl req -new -days 1000 -nodes -key host1-key.pem host1-csr.pem /usr/bin/openssl x509 -req -in host1-csr.pem -days 1000 -CA ca-cert.pem -CAkey ca-key.pem -set_serial 01 host1-cert.pem rm host1-csr.pem host1-cert.pem This is driving me crazy, and I'll happily try any suggestions and post results. If I'm just totally noobing out on this one, feel free to jibe away. You can't possibly hurt my feelings. :)

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• Script working with mysql and php into a textarea and back

  - by Tribalcomm

  I am trying to write a custom script that will keep a list of strings in a textarea. Each line of the textarea will be a row from a table. The problem I have is how to work the script to allow for adding, updating, or deleting rows based on a submit. So, for instance, I currently have 3 rows in the database: john sue mark I want to be able to delete sue and add richard and it will delete the row with sue and insert a row for richard. My code so far is as follows: To query the db and list it in the textarea: $basearray = mysql_query("SELECT name FROM mytable ORDER BY name"); <textarea name="names" cols=6 rows=12>'); <?php foreach($basearray as $base){ echo $base->name."\n"; } ?> </textarea> After the submit, I have: <?php $namelist = $_REQUEST[names]; $newarray = explode("\n", $namelist); foreach($newarray as $name) { if (!in_array($name, $basearray)) { mysql_query(DELETE FROM mytable WHERE word='$name'"); } elseif (in_array($name, $basearray)) { ; } else { mysql_query("INSERT INTO mytable (name) VALUES ("$name")"); } } ?> Please tell me what I am doing wrong. I am not getting any functions to work when I edit the contents of the textarea. Thanks!

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• High-concurrency counters without sharding

  - by dound

  This question concerns two implementations of counters which are intended to scale without sharding (with a tradeoff that they might under-count in some situations): http://appengine-cookbook.appspot.com/recipe/high-concurrency-counters-without-sharding/ (the code in the comments) http://blog.notdot.net/2010/04/High-concurrency-counters-without-sharding My questions: With respect to #1: Running memcache.decr() in a deferred, transactional task seems like overkill. If memcache.decr() is done outside the transaction, I think the worst-case is the transaction fails and we miss counting whatever we decremented. Am I overlooking some other problem that could occur by doing this? What are the significiant tradeoffs between the two implementations? Here are the tradeoffs I see: #2 does not require datastore transactions. To get the counter's value, #2 requires a datastore fetch while with #1 typically only needs to do a memcache.get() and memcache.add(). When incrementing a counter, both call memcache.incr(). Periodically, #2 adds a task to the task queue while #1 transactionally performs a datastore get and put. #1 also always performs memcache.add() (to test whether it is time to persist the counter to the datastore). Conclusions (without actually running any performance tests): #1 should typically be faster at retrieving a counter (#1 memcache vs #2 datastore). Though #1 has to perform an extra memcache.add() too. However, #2 should be faster when updating counters (#1 datastore get+put vs #2 enqueue a task). On the other hand, with #1 you have to be a bit more careful with the update interval since the task queue quota is almost 100x smaller than either the datastore or memcahce APIs.

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• rapid application developement tools for very basic GUI apps

  - by Jurij

  I know there are many RAD platforms out there. Infact there are so many that I'm having a hard time finding out which one fits me best. What I want is a RAD tool that would allow me to define a database data model (make DB tables) and then create (view and edit) forms for the various tables. Data input, updating and various queries should be easy and GUI should generate automatically. I'd like to add some additional functionality by coding (such as various complex calculations on the data). I'm a programmer so I'm willing to learn to use a more complete, full-blown RAD solution if you can point me to it (NetBeans and RubyOnRails being the two such frameworks that I'd would probably be high on the list). I'm currently doing Windows Forms logistics apps in .NET. I've actually developed a very crude and basic version of what I need, but I just know that there are solutions out there that are much better and I'd benefit by knowing how to use them. So in short, the basic requirements: * database based data storage (SQLite if possible) * very automated GUI creation * desktop based (as in: not a web app) * extendable by coding * used for creating simple data entry, view & query apps. So basically something like Oracle Forms or DotNetMushroom Rapid Application Developer. But for .NET and SQLite if possible.

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• Data Binding to an object in C#

  - by Allen

  Objective-c/cocoa offers a form of binding where a control's properties (ie text in a textbox) can be bound to the property of an object. I am trying to duplicate this functionality in C# w/ .Net 3.5. I have created the following very simple class in the file MyClass.cs: class MyClass { private string myName; public string MyName { get { return myName; } set { myName = value; } } public MyClass() { myName = "Allen"; } } I also created a simple form with 1 textbox and 1 button. I init'd one instance of Myclass inside the form code and built the project. Using the DataSource Wizard in Vs2008, i selected to create a data source based on object, and selected the MyClass assembly. This created a datasource entity. I changed the databinding of the textbox to this datasource; however, the expected result (that the textbox's contents would be "allen") was not achieved. Further, putting text into the textbox is not updating the name property of the object. I know i'm missing something fundamental here. At some point i should have to tie my instance of the MyClass class that i initialized inside the form code to the textbox, but that hasn't occurred. Everything i've looked at online seems to gloss over using DataBinding with an object (or i'm missing the mark entirely), so any help is great appreciated. ----Edit--- Utilizing what i learned by the answers, i looked at the code generated by Visual Studio, it had the following: this.myClassBindingSource.DataSource = typeof(BindingTest.MyClass); if i comment that out and substitute : this.myClassBindingSource.DataSource = new MyClass(); i get the expected behavior. Why is the default code generated by VS like it is? Assuming this is more correct than the method that works, how should i modify my code to work within the bounds of what VS generated?

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