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  • C++ destructor problem with boost::scoped_ptr

    - by bb-generation
    I have a question about the following code: #include <iostream> #include <boost/scoped_ptr.hpp> class Interface { }; class A : public Interface { public: A() { std::cout << "A()" << std::endl; } virtual ~A() { std::cout << "~A()" << std::endl; } }; Interface* get_a() { A* a = new A; return a; } int main() { { std::cout << "1" << std::endl; boost::scoped_ptr<Interface> x(get_a()); std::cout << "2" << std::endl; } std::cout << "3" << std::endl; } It creates the following output: 1 A() 2 3 As you can see, it doesn't call the destructor of A. The only way I see to get the destructor of A being called, is to add a destructor for the Interface class like this: virtual ~Interface() { } But I really want to avoid any Implementation in my Interface class and virtual ~Interface() = 0; doesn't work (produces some linker errors complaining about a non existing implementation of ~Interface(). So my question is: What do I have to change in order to make the destructor being called, but (if possible) leave the Interface as an Interface (only abstract methods).

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  • iBatis not populating object when there are no rows found.

    - by Omnipresent
    I am running a stored procedure that returns 2 cursors and none of them have any data. I have the following mapping xml: <resultMap id="resultMap1" class="HashMap"> <result property="firstName" columnIndex="2"/> </resultMap> <resultMap id="resultMap2" class="com.somePackage.MyBean"> <result property="unitStreetName" column="street_name"/> </resultMap> <parameterMap id="parmmap" class="map"> <parameter property="id" jdbcType="String" javaType="java.lang.String" mode="IN"/> <parameter property="Result0" jdbcType="ORACLECURSOR" javaType="java.sql.ResultSet" mode="OUT" resultMap="resultMap1"/> <parameter property="Result1" jdbcType="ORACLECURSOR" javaType="java.sql.ResultSet" mode="OUT" resultMap="resultMap2"/> </parameterMap> <procedure id="proc" parameterMap="parmmap"> { call my_sp (?,?,?) } </procedure> First result set is being put in a HashMap...second resultSet is being put in a MyBean class. code in my DAO follows: HashMap map = new HashMap() map.put("id", "1234"); getSqlMapClientTemplate().queryForList("mymap.proc", map); HashMap result1 = (HashMap)((List)parmMap.get("Result0")).get(0); MyBean myObject = (MyBean)((List)parmMap.get("Result1")).get(0);//code fails here in the last line above..my code fails. It fails because second cursor has no rows and thats why nothing is put into the list. However, first cursor returns nothing as well but since results are being put into a HashMap the list for first cursor atleast has HashMap object inside it.. Why this difference? is there a way to make iBatis put an object of MyBean inside the list even if there are no rows returned? Or should I be handling this in my DAO...I want to avoid handling it in the DAO because I have whole bunch of DAO's like these.

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  • How do I fix the alpha value after calling GDI text functions?

    - by Daniel Stutzbach
    I have a application that uses the Aero glass effect, so each pixel has an alpha value in addition to red, green, and blue values. I have one custom-draw control that has a solid white background (alpha = 255). I would like to draw solid text on the control using the GDI text functions. However, these functions set the alpha value to an arbitrary value, causing the text to translucently show whatever window is beneath my application's. After calling rendering the text, I would like to go through all of the pixels in the control and set their alpha value back to 255. What's the best way to do that? I haven't had any luck with the BitBlt, GetPixel, and SetPixel functions. They appear to be oblivious to the alpha value. Here are other solutions that I have considered and rejected: Draw to a bitmap, then copy the bitmap to the device: With this approach, the text rendering does not make use of the characteristics of the monitor (e.g., ClearText). Use GDI+ for text rendering: This application originally used GDI+ for text rendering (before I started working on Aero support). I switched to GDI because of difficulties I encountered trying to accurately measure strings with GDI+. I'd rather not switch back. Set the Aero region to avoid the control in question: My application's window is actually a child window of a different application running in a different process. I don't have direct control over the Aero settings on the top-level window. The application is written in C# using Windows Forms, though I'm not above using Interop to call Win32 API functions.

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  • Issue with transparent texture on 3D primitive, XNA 4.0

    - by Bevin
    I need to draw a large set of cubes, all with (possibly) unique textures on each side. Some of the textures also have parts of transparency. The cubes that are behind ones with transparent textures should show through the transparent texture. However, it seems that the order in which I draw the cubes decides if the transparency works or not, which is something I want to avoid. Look here: cubeEffect.CurrentTechnique = cubeEffect.Techniques["Textured"]; Block[] cubes = new Block[4]; cubes[0] = new Block(BlockType.leaves, new Vector3(0, 0, 3)); cubes[1] = new Block(BlockType.dirt, new Vector3(0, 1, 3)); cubes[2] = new Block(BlockType.log, new Vector3(0, 0, 4)); cubes[3] = new Block(BlockType.gold, new Vector3(0, 1, 4)); foreach(Block b in cubes) { b.shape.RenderShape(GraphicsDevice, cubeEffect); } This is the code in the Draw method. It produces this result: As you can see, the textures behind the leaf cube are not visible on the other side. When i reverse index 3 and 0 on in the array, I get this: It is clear that the order of drawing is affecting the cubes. I suspect it may have to do with the blend mode, but I have no idea where to start with that.

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  • Strategies for Synchronizing Data Between a Rails App and iPhone App

    - by jessecurry
    I've written many iPhone Applications that have pulled data from web services and I've worked on synchronizing data between an iPhone App and a Web Application, but I've always felt that there is probably a better way to handle the synchronization. I'd like to know what strategies you have used to synchronize data between your iPhone(read: mobile) Apps and your Rails(read: web) Applications. Are there any strategies that scale particularly well? How have you dealt with large amounts of data? (Do you use paged responses?) How do you make sure that data is not overwritten? Is there a reason to avoid Ruby on Rails? if so, can you suggest an alternative? What is better about the alternative? What strategies have failed? Why do you believe that those strategies failed? I would like to be able to keep all of the data modifications on the server, but the particular application I am about to start work on will need the ability to operate while disconnected from the network. The user will be able to update data on the mobile device and update data through the web application. When the user's mobile device connects to the server any local changes will be pushed to the server.

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  • Overriding Code Igniter 2.14's global_xss_filtering settting

    - by user2353007
    I have created the following file at: application/core/MY_Security.php <?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); /* * Does not work with global xss */ class MY_Security extends CI_Security { function xss_clean($str, $is_image = FALSE) { $CI =& get_instance(); $CI->load->library('My_cleaner'); return $CI->my_cleaner->clean_html($str); } } this works great for $this-input-post('post_var', TRUE); and $this-security-xss_clean($input); It is working very well except when I go into application/config/config.php and change $config['global_xss_filtering] = FALSE; to $config['global_xss_filtering] = TRUE; in that case, I just get a white page on every controllers action/function. Does anybody know what else I have to change to get global_xss_filtering = TRUE; to work when overriding the xss_clean function in system/core/Security.php through application/core/MY_Security.php? I'm guessing it might be something with the loader but I'm not sure where to start. The next option is to just replace the function in the system/core/Security.php file which I am trying to avoid. Thanks.

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  • error catching exception while System.out.print

    - by user1702633
    I have 2 classes, one that implements a double lookup( int i); and one where I use that lookup(int i) in solving a question, or in this case printing the lookup values. This case is for an array. So I read the exception documentation or google/textbook and come with the following code: public double lookup(int i) throws Exception { if( i > numItems) throw new Exception("out of bounds"); return items[i]; } and take it over to my class and try to print my set, where set is a name of the object type I define in the class above. public void print() { for (int i = 0; i < set.size() - 1; i++) { System.out.print(set.lookup(i) + ","); } System.out.print(set.lookup(set.size())); } I'm using two print()'s to avoid the last "," in the print, but am getting an unhandled exception Exception (my exception's name was Exception) I think I have to catch my exception in my print() but cannot find the correct formatting online. Do I have to write catch exception Exception? because that gives me a syntax error saying invalid type on catch. Sources like http://docs.oracle.com/javase/tutorial/essential/exceptions/ are of little help to me, I'm can't seem to grasp what the text is telling me. I'm also having trouble finding sources with multiple examples where I can actually understand the coding in the examples. so could anybody give me a source/example for the above catch phrase and perhaps a decent source of examples for new Java programmers? my book is horrendous and I cannot seem to find an understandable example for the above catch phrase online.

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  • Invoking code both before and after WebControl.Render method

    - by Dirk
    I have a set of custom ASP.NET server controls, most of which derive from CompositeControl. I want to implement a uniform look for "required" fields across all control types by wrapping each control in a specific piece of HTML/CSS markup. For example: <div class="requiredInputContainer"> ...custom control markup... </div> I'd love to abstract this behavior in such a way as to avoid having to do something ugly like this in every custom control, present and future: public class MyServerControl : TextBox, IRequirableField { public IRequirableField.IsRequired {get;set;} protected override void Render(HtmlTextWriter writer){ RequiredFieldHelper.RenderBeginTag(this, writer) //render custom control markup RequiredFieldHelper.RenderEndTag(this, writer) } } public static class RequiredFieldHelper{ public static void RenderBeginTag(IRequirableField field, HtmlTextWriter writer){ //check field.IsRequired, render based on its values } public static void RenderEndTag(IRequirableField field, HtmlTextWriter writer){ //check field.IsRequired , render based on its values } } If I was deriving all of my custom controls from the same base class, I could conceivably use Template Method to enforce the before/after behavior;but I have several base classes and I'd rather not end up with really a convoluted class hierarchy anyway. It feels like I should be able to design something more elegant (i.e. adheres to DRY and OCP) by leveraging the functional aspects of C#, but I'm drawing a blank.

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  • RewriteRule to store thousands of files in subdirectories

    - by Brandon
    I have a website that will have millions of pages in a directory. I'd like to store those files on-disk in a bunch of subdirectories based on the first characters of the page name. For example http://mysite.com/hugedir/somefile.html would be stored in /var/www/html/hugedir/s/o/m/e/f/ile.html That is fairly trivial to do with a RewriteRule like so: RewriteRule ^hugedir/(.)(.)(.)(.)(.)(.*).html /hugedir/{$1}/{$2}/{$3}/{$4}/{$5}/$6.html RewriteRule ^hugedir/(.)(.)(.)(.)(.*).html /hugedir/{$1}/{$2}/{$3}/{$4}/{$5}.html RewriteRule ^hugedir/(.)(.)(.)(.*).html /hugedir/{$1}/{$2}/{$3}/{$4}.html RewriteRule ^hugedir/(.)(.)(.*).html /hugedir/{$1}/{$2}/{$3}.html RewriteRule ^hugedir/(.)(.*).html /hugedir/{$1}/{$2}.html RewriteRule ^hugedir/(.*).html /hugedir/{$1}.html However, the file name may contain hyphens or other non-standard characters and I'd really like to avoid having a directory named with a strange character. Ideally, I'd like to have a list of 'approved' characters and either eliminate or transform the unapproved characters to an underscore. Can anybody think of a way to do that? Or something else equivalent? Part of the requirement is that these be physical files on disk and it not be parsed with a scripting language.

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  • Generating different randoms valid for a day on different independent devices?

    - by Pentium10
    Let me describe the system. There are several mobile devices, each independent from each other, and they are generating content for the same record id. I want to avoid generating the same content for the same record on different devices, for this I though I would use a random and make it so too cluster the content pool based on these randoms. Suppose you have choices from 1 to 100. Day 1 Device#1 will choose for the record#33 between 1-10 Device#2 will choose for the record#33 between 40-50 Device#3 will choose for the record#33 between 50-60 Device#1 will choose for the record#55 between 40-50 Device#2 will choose for the record#55 between 1-10 Device#3 will choose for the record#55 between 10-20 Device#1 will choose for the record#11 between 1-10 Device#2 will choose for the record#22 between 1-10 Device#3 will choose for the record#99 between 1-10 Day 2 Device#1 will choose for the record#33 between 90-100 Device#2 will choose for the record#33 between 1-10 Device#3 will choose for the record#33 between 50-60 They don't have access to a central server. Data available for each of them: IMEI (unique per mobile) Date of today (same on all devices) Record id (same on all devices) What do you think, how is it possible? ps. tags can be edited

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  • are there requirements for Struts setters beyond variable name matching?

    - by slk
    I have a model-driven Struts Web action: public class ModelDrivenAction<T extends Object> implements ModelDriven<T>, Preparable { protected Long id; protected T model; @Override public void prepare() {} public void setId(Long id) { this.id = id; } @Override public T getModel() { return model; } public void setModel(T model) { this.model = model; } } I have another action which is not currently model-driven: public class OtherAction implements Preparable { private ModelObj modelObj; private Long modelId; @Override public void prepare() { modelObj = repoService.retrieveModelById(modelId); } public void setModelId(Long modelId) { this.modelId = modelId; } } I wish to make it so, and would like to avoid having to track down all the instances in JavaScript where the action is passed a "modelId" parameter instead of "id" if at all possible. I thought this might work, so either modelId or id could be passed in: public class OtherAction extends ModelDrivenAction<ModelObj> { @Override public void prepare() { model = repoService.retrieveModelById(id); } public void setModelId(Long modelId) { this.id = modelId; } } However, server/path/to/other!method?modelId=123 is failing to set id. I thought so long as a setter matched a parameter name the Struts interceptor would call it on action invocation. Am I missing something here?

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  • Void* array casting to float, int32, int16, etc.

    - by Griffin
    Hey guys, I've got an array of PCM data, it could be 16 bit, 24 bit packed, 32 bit, etc.. It could be signed, or unsigned, and it could be 32 or 64 bit floating point. It is currently stored as a "void**" matrix, indexed by channel, then by frame. The goal is to allow my library to take in any PCM format and buffer it, without requiring manipulation of the data to fit a designated structure. If the A/D converter spits out 24 bit packed arrays of interleaved PCM, I need to accept it gracefully. I also need to support 16 bit non interleaved, as well as any permutation of the above formats. I know the bit depth and other information at runtime, and I'm trying to code efficiently while not duplicating code. What I need is an effective way to cast the matrix, put PCM data into the matrix, and then pull it out later. I can cast the matrix to int32_t, or int16_t for the 32 and 16 bit signed PCM respectively, I'll probably have to store the 24 bit PCM in an int32_t for 32 bit, 8 bit byte systems as well. Can anyone recommend a good way to put data into this array, and pull it out later? I'd like to avoid large sections of code which look like: switch( mFormat ) { case 1: // unsigned 8 bit for( int i = 0; i < mChannels; i++ ) framesArray = (uint8_t*)pcm[i]; break; case 2: // signed 8 bit for( int i = 0; i < mChannels; i++ ) framesArray = (int8_t*)pcm[i]; break; case 3: // unsigned 16 bit ... Limitations: I'm working in C/C++, no templates, no RTTI, no STL. Think embedded. Things get trickier when I have to port this to a DSP with 16 bit bytes. Does anybody have any useful macros they might be willing to share? Thanks, -Griff

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  • Android CursorAdapters, ListViews and background threads

    - by MattC
    This application I've been working on has databases with multiple megabytes of data to sift through. A lot of the activities are just ListViews descending through various levels of data within the databases until we reach "documents", which is just HTML to be pulled from the DB(s) and displayed on the phone. The issue I am having is that some of these activities need to have the ability to search through the databases by capturing keystrokes and re-running the query with a "like %blah%" in it. This works reasonably quickly except when the user is first loading the data and when the user first enters a keystroke. I am using a ResourceCursorAdapter and I am generating the cursor in a background thread, but in order to do a listAdapter.changeCursor(), I have to use a Handler to post it to the main UI thread. This particular call is then freezing the UI thread just long enough to bring up the dreaded ANR dialog. I'm curious how I can offload this to a background thread totally so the user interface remains responsive and we don't have ANR dialogs popping up. Just for full disclosure, I was originally returning an ArrayList of custom model objects and using an ArrayAdapter, but (understandably) the customer pointed out it was bad memory-manangement and I wasn't happy with the performance anyways. I'd really like to avoid a solution where I'm generating huge lists of objects and then doing a listAdapter.notifyDataSetChanged/Invalidated() Here is the code in question: private Runnable filterDrugListRunnable = new Runnable() { public void run() { if (filterLock.tryLock() == false) return; cur = ActivityUtils.getIndexItemCursor(DrugListActivity.this); if (cur == null || forceRefresh == true) { cur = docDb.getItemCursor(selectedIndex.getIndexId(), filter); ActivityUtils.setIndexItemCursor(DrugListActivity.this, cur); forceRefresh = false; } updateHandler.post(new Runnable() { public void run() { listAdapter.changeCursor(cur); } }); filterLock.unlock(); updateHandler.post(hideProgressRunnable); updateHandler.post(updateListRunnable); } };

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  • Processing a database queue across multiple threads - design advice

    - by rwmnau
    I have a SQL Server table full of orders that my program needs to "follow up" on (call a webservice to see if something has been done with them). My application is multi-threaded, and could have instances running on multiple servers. Currently, every so often (on a Threading timer), the process selects 100 rows, at random (ORDER BY NEWID()), from the list of "unconfirmed" orders and checks them, marking off any that come back successfully. The problem is that there's a lot of overlap between the threads, and between the different processes, and their's no guarantee that a new order will get checked any time soon. Also, some orders will never be "confirmed" and are dead, which means that they get in the way of orders that need to be confirmed, slowing the process down if I keep selecting them over and over. What I'd prefer is that all outstanding orders get checked, systematically. I can think of two easy ways do this: The application fetches one order to check at a time, passing in the last order it checked as a parameter, and SQL Server hands back the next order that's unconfirmed. More database calls, but this ensures that every order is checked in a reasonable timeframe. However, different servers may re-check the same order in succession, needlessly. The SQL Server keeps track of the last order it asked a process to check up on, maybe in a table, and gives a unique order to every request, incrementing its counter. This involves storing the last order somewhere in SQL, which I wanted to avoid, but it also ensures that threads won't needlessly check the same orders at the same time Are there any other ideas I'm missing? Does this even make sense? Let me know if I need some clarification.

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  • HMAC URLs instead of login?

    - by Tres
    In implementing my site (a Rails site if it makes any difference), one of my design priorities is to relieve the user of the need to create yet another username and password while still providing useful per-user functionality. The way I am planning to do this is: User enters information on the site. Information is associated with the user via server-side session. User completes entering information, server sends an access URL via e-mail to the user roughly in the form of: http://siteurl/<user identifier>/<signature: HMAC(secret + salt + user identifier)> User clicks URL, site looks up user ID and salt and computes the HMAC with the server-stored secret and authenticates if the computed HMAC and signature match. My question is: is this a reasonably secure way to accomplish what I'm looking to do? Are there common attacks that would render it useless? Is there a compelling reason to abandon my desire to avoid a username/password? Is there a must-read book or article on the subject? Note that I'm not dealing with credit card numbers or anything exceedingly private, but I would still like to keep the information reasonably secure.

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  • Proper API Design for Version Independence?

    - by Justavian
    I've inherited an enormous .NET solution of about 200 projects. There are now some developers who wish to start adding their own components into our application, which will require that we begin exposing functionality via an API. The major problem with that, of course, is that the solution we've got on our hands contains such a spider web of dependencies that we have to be careful to avoid sabotaging the API every time there's a minor change somewhere in the app. We'd also like to be able to incrementally expose new functionality without destroying any previous third party apps. I have a way to solve this problem, but i'm not sure it's the ideal way - i was looking for other ideas. My plan would be to essentially have three dlls. APIServer_1_0.dll - this would be the dll with all of the dependencies. APIClient_1_0.dll - this would be the dll our developers would actual refer to. No references to any of the mess in our solution. APISupport_1_0.dll - this would contain the interfaces which would allow the client piece to dynamically load the "server" component and perform whatever functions are required. Both of the above dlls would depend upon this. It would be the only dll that the "client" piece refers to. I initially arrived at this design, because the way in which we do inter process communication between windows services is sort of similar (except that the client talks to the server via named pipes, rather than dynamically loading dlls). While i'm fairly certain i can make this work, i'm curious to know if there are better ways to accomplish the same task.

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  • Flex 3 - Remove image flickering

    - by BS_C3
    Hello Community! I have an application with different components that are accessible through a viewstack in the main application. The main application looks like that: <Application> <Viewstack> <myComponent1/> <myComponent2/> <myComponent3/> . . . </Viewstack> </Application> In myComponent1, I have a horizontalList where the user can select a product. In myComponent2, I have 2 containers inside the component. A left container with a larger image of the product selected in myComponent1 and a right container with all characteristics of the product. Both containers have an embed background image. When I select a product in myComponent1, the application displays myComponent2. When the component is displayed, I first see the page without the large image of the product, then both containers flickers and the product image is displayed. How could I avoid this flickering? It's really annoying _< Thanks in advance for your help =) Regards. BS_C3

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  • Refreshing a MKMapView when the user location is updated or using default values

    - by koichirose
    I'm trying to refresh my map view and load new data from the server when the device acquires the user location. Here's what I'm doing: - (void)viewDidLoad { CGRect bounds = self.view.bounds; mapView = [[MKMapView alloc] initWithFrame:bounds]; mapView.showsUserLocation=YES; mapView.delegate=self; [self.view insertSubview:mapView atIndex:0]; [self refreshMap]; } - (void)mapView:(MKMapView *)theMapView didUpdateUserLocation:(MKUserLocation *)userLocation { //this is to avoid frequent updates, I just need one position and don't need to continuously track the user's location if (userLocation.location.horizontalAccuracy > self.myUserLocation.location.horizontalAccuracy) { self.myUserLocation = userLocation; CLLocationCoordinate2D centerCoord = { userLocation.location.coordinate.latitude, userLocation.location.coordinate.longitude }; [theMapView setCenterCoordinate:centerCoord zoomLevel:10 animated:YES]; [self refreshMap]; } } - (void)refreshMap { [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES]; [self.mapView removeAnnotations:self.mapView.annotations]; //default position NSString *lat = @"45.464161"; NSString *lon = @"9.190336"; if (self.myUserLocation != nil) { lat = [[NSNumber numberWithDouble:myUserLocation.coordinate.latitude] stringValue]; lon = [[NSNumber numberWithDouble:myUserLocation.coordinate.longitude] stringValue]; } NSString *url = [[NSString alloc] initWithFormat:@"http://myserver/geo_search.json?lat=%@&lon=%@", lat, lon]; NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:url] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:60.0]; [[NSURLConnection alloc] initWithRequest:theRequest delegate:self]; [url release]; [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO]; } I also have a - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data, to create and add the annotations. Here's what happens: sometimes I get the location after a while, so I already loaded data close to the default location. Then I get the location and it should remove the old annotations and add the new ones, instead I keep seeing the old annotations and the new ones are added anyway (let's say I receive 10 annotations each time, so it means that I have 20 on my map when I should have 10). What am I doing wrong?

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  • "Detecting" and loading of "plugins" in GAE

    - by Patrick Cornelissen
    Hi! I have a "plugin like" architecture and I want to create one instance of each class that implements a dedicated interface and put these in a cache. (To have a singleton-ish effect). The plugins will be provided as jars and put into the app engine war file before the app is uploaded. I have tried to use the ClassPathScanningCandidateComponentProvider as I'm using spring anyway, but this didn't work. The provider complained that it was not able to find the HttpServletResponse class file while scanning the classpath. I can't get around this, when I add the servlet jar, then I'll get of course problems, because the same jar is also provided by the GAE. If I don't, I'm getting the error above... So I tried to add a static initialization code, but of course this doesn't work, because the class is initialized when it's instantiated for the first time. (Well I knew that but it was worth a try) The last chance I currently see is that I create a properties file with all plugin classes when the package is created, but this requires writing of a maven plugin etc. and I'd like to avoid that. Is there something that I am missing?

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  • Test the sequentiality of a column with a single SQL query

    - by LauriE
    Hey, I have a table that contains sets of sequential datasets, like that: ID set_ID some_column n 1 'set-1' 'aaaaaaaaaa' 1 2 'set-1' 'bbbbbbbbbb' 2 3 'set-1' 'cccccccccc' 3 4 'set-2' 'dddddddddd' 1 5 'set-2' 'eeeeeeeeee' 2 6 'set-3' 'ffffffffff' 2 7 'set-3' 'gggggggggg' 1 At the end of a transaction that makes several types of modifications to those rows, I would like to ensure that within a single set, all the values of "n" are still sequential (rollback otherwise). They do not need to be in the same order according to the PK, just sequential, like 1-2-3 or 3-1-2, but not like 1-3-4. Due to the fact that there might be thousands of rows within a single set I would prefer to do it in the db to avoid the overhead of fetching the data just for verification after making some small changes. Also there is the issue of concurrency. The way locking in InnoDB (repeatable read) works (as I understand) is that if I have an index on "n" then InnoDB also locks the "gaps" between values. If I combine set_ID and n to a single index, would that eliminate the problem of phantom rows appearing? Looks to me like a common problem. Any brilliant ideas? Thanks! Note: using MySQL + InnoDB

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  • How to do "map chunks", like terraria or minecraft maps?

    - by O'poil
    Due to performance issues, I have to cut my maps into chunks. I manage the maps in this way: listMap[x][y] = new Tile (x,y); I tried in vain to cut this list for several "chunk" to avoid loading all the map because the fps are not very high with large map. And yet, when I update or Draw I do it with a little tile range. Here is how I proceed: foreach (List<Tile> list in listMap) { foreach (Tile leTile in list) { if ((leTile.Position.X < screenWidth + hero.Pos.X) && (leTile.Position.X > hero.Pos.X - tileSize) && (leTile.Position.Y < screenHeight + hero.Pos.Y) && (leTile.Position.Y > hero.Pos.Y - tileSize) ) { leTile.Draw(spriteBatch, gameTime); } } } (and the same thing, for the update method). So I try to learn with games like minecraft or terraria, and any two manages maps much larger than mine, without the slightest drop of fps. And apparently, they load "chunks". What I would like to understand is how to cut my list in Chunk, and how to display depending on the position of my character. I try many things without success. Thank you in advance for putting me on the right track! Ps : Again, sorry for my English :'( Pps : I'm not an experimented developer ;)

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  • Can I set Java max heap size for running from a jar file?

    - by Kip
    I am launching a java jar file which often requires more than the default 64MB max heap size. A 256MB heap size is sufficient for this app though. Is there anyway to specify (in the manifest maybe?) to always use a 256MB max heap size when launching the jar? (More specific details below, if needed.) This is a command-line app that I've written in Java, which does some image manipulation. On high-res images (about 12 megapixels and above, which is not uncommon) I get an OutOfMemoryError. Currently I'm launching the app from a jar file, i.e. java -jar MyApp.jar params... I can avoid an OutOfMemoryError by specifying 256MB max heap size on the command line, i.e.: java -Xmx256m -jar MyApp.jar params... However, I don't want to have to specify this, since I know that 256MB is sufficient even for high-res images. I'd like to have that information saved in the jar file. Is that possible?

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  • Selectively search and replace certain lines using a regular expression

    - by eneveu
    I have a file containing a lot of SQL statements, such as: CREATE TABLE "USER" ( "ID" INTEGER PRIMARY KEY, "NAME" CHARACTER VARYING(50) NOT NULL, "AGE" INTEGER NOT NULL ); COPY "USER" (id, name, age) FROM stdin; 1 Skywalker 19 2 Kenobi 57 I want the column names in the COPY statements to be uppercased and quoted: COPY "USER" ("ID", "NAME", "AGE") FROM stdin; Using sed, I found the following regexp: sed -r 's/([( ])(\w+)([,)])/\1"\U\2\E"\3/g' It does replace the column names, but it is not selective enough, and replaces other words in the file: ~/test]$sed -r 's/([( ])(\w+)([,)])/\1"\U\2\E"\3/g' star_wars_example CREATE TABLE "USER" ( "ID" INTEGER PRIMARY "KEY", "NAME" CHARACTER VARYING("50")NOT "NULL", "AGE" INTEGER NOT NULL ); COPY "USER" ("ID", "NAME", "AGE") FROM stdin; 1 Skywalker 19 2 Kenobi 57 To avoid this problem, I want sed to only apply my regexp to the lines starting with COPY and ending with FROM stdin;. I have looked into lookahead / lookbehind, but they are not supported in sed. They seem to be supported in super-sed, but I am currently using Cygwin (Windows is mandatory here...) and it does not seem available in the package list. Is there a way to force sed to only consider specific line? I've considered piping my file through grep before applying sed, but other lines will then disappear from the output. Am I missing something obvious? It would be great if the answer was easily applicable on a default Cygwin install. I guess I could try installing super-sed on cygwin, but I'd like to know if there are more obvious ideas

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  • How To Run MSBuild scripts in .wixproj?

    - by hisoka21
    Im trying to learn to make a web installer using Windows Installer XML (WIX 3.5). I found this blog about using msbuild in .wixproj files to avoid the scenario where the installer ends up dropping the web project assemblies right in the root of the app instead of keeping them in the bin folder like they're supposed to be. Here is the link to that: <http://www.paraesthesia.com/archive/2010/07/30/how-to-consume-msdeploy-staged-web-site-output-in-a.aspx But after adding the MSBuild scripts in the .wixproj file, I don't know what to do anymore. According to the instruction after adding the MSBuild script: "When that target runs, you'll see a .wxs file pop out in the .wixproj project folder. Add the generated .wxs to your .wixproj project so it knows to include it in the build." I really don7t know what this means. How can I run the target? I tried to build it but there was no .wxs file generated in the .wixproj folder. Am I missing something? Please help...

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  • avoiding code duplication in Rails 3 models

    - by Dustin Frazier
    I'm working on a Rails 3.1 application where there are a number of different enum-like models that are stored in the database. There is a lot of identical code in these models, as well as in the associated controllers and views. I've solved the code duplication for the controllers and views via a shared parent controller class and the new view/layout inheritance that's part of Rails 3. Now I'm trying to solve the code duplication in the models, and I'm stuck. An example of one of my enum models is as follows: class Format < ActiveRecord::Base has_and_belongs_to_many :videos attr_accessible :name validates :name, presence: true, length: { maximum: 20 } before_destroy :verify_no_linked_videos def verify_no_linked_videos unless self.videos.empty? self.errors[:base] << "Couldn't delete format with associated videos." raise ActiveRecord::RecordInvalid.new self end end end I have four or five other classes with nearly identical code (the association declaration being the only difference). I've tried creating a module with the shared code that they all include (which seems like the Ruby Way), but much of the duplicate code relies on ActiveRecord, so the methods I'm trying to use in the module (validate, attr_accessible, etc.) aren't available. I know about ActiveModel, but that doesn't get me all the way there. I've also tried creating a common, non-persistent parent class that subclasses ActiveRecord::Base, but all of the code I've seen to accomplish this assumes that you won't have subclasses of your non-persistent class that do persist. Any suggestions for how best to avoid duplicating these identical lines of code across many different enum models?

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