Search Results

Search found 13867 results on 555 pages for 'avoid learning'.

Page 483/555 | < Previous Page | 479 480 481 482 483 484 485 486 487 488 489 490  | Next Page >

  • Using `<List>` when dealing with pointers in C#.

    - by Gorchestopher H
    How can I add an item to a list if that item is essentially a pointer and avoid changing every item in my list to the newest instance of that item? Here's what I mean: I am doing image processing, and there is a chance that I will need to deal with images that come in faster than I can process (for a short period of time). After this "burst" of images I will rely on the fact that I can process faster than the average image rate, and will "catch-up" eventually. So, what I want to do is put my images into a <List> when I acquire them, then if my processing thread isn't busy, I can take an image from that list and hand it over. My issue is that I am worried that since I am adding the image "Image1" to the list, then filling "Image1" with a new image (during the next image acquisition) I will be replacing the image stored in the list with the new image as well (as the image variable is actually just a pointer). So, my code looks a little like this: while (!exitcondition) { if(ImageAvailabe()) { Image1 = AcquireImage(); ImgList.Add(Image1); } if(ImgList.Count 0) { ProcessEngine.NewImage(ImgList[0]); ImgList.RemoveAt(0); } } Given the above, how can I ensure that: - I don't replace all items in the list every time Image1 is modified. - I don't need to pre-declare a number of images in order to do this kind of processing. - I don't create a memory devouring monster. Any advice is greatly appreciated.

    Read the article

  • EF/LINQ: Where() against a property of a subtype

    - by ladenedge
    I have a set of POCOs, all of which implement the following simple interface: interface IIdObject { int Id { get; set; } } A subset of these POCOs implement this additional interface: interface IDeletableObject : IIdObject { bool IsDeleted { get; set; } } I have a repository hierarchy that looks something like this: IRepository<T <: BasicRepository<T <: ValidatingRepository<T (where T is IIdObject) I'm trying to add a FilteringRepository to the hierarchy such that all of the POCOs that implement IDeletableObject have a Where(p => p.IsDeleted == false) filter applied before any other queries take place. My goal is to avoid duplicating the hierarchy solely for IDeletableObjects. My first attempt looked like this: public override IQueryable<T> Query() { return base.Query().Where(t => ((IDeletableObject)t).IsDeleted == false); } This works well with LINQ to Objects, but when I switch to an EF backend I get: "LINQ to Entities only supports casting Entity Data Model primitive types." I went on to try some fancier parameterized solutions, but they ultimately failed because I couldn't make T covariant in the following case for some reason I don't quite understand: interface IQueryFilter<out T> // error { Expression<Func<T, bool>> GetFilter(); } I'd be happy to go into more detail on my more complicated solutions if it would help, but I think I'll stop here for now in hope that someone might have an idea for me to try. Thanks very much in advance!

    Read the article

  • Providing less than operator for one element of a pair

    - by Koszalek Opalek
    What would be the most elegant way too fix the following code: #include <vector> #include <map> #include <set> using namespace std; typedef map< int, int > row_t; typedef vector< row_t > board_t; typedef row_t::iterator area_t; bool operator< ( area_t const& a, area_t const& b ) { return( a->first < b->first ); }; int main( int argc, char* argv[] ) { int row_num; area_t it; set< pair< int, area_t > > queue; queue.insert( make_pair( row_num, it ) ); // does not compile }; One way to fix it is moving the definition of less< to namespace std (I know, you are not supposed to do it.) namespace std { bool operator< ( area_t const& a, area_t const& b ) { return( a->first < b->first ); }; }; Another obvious solution is defining less than< for pair< int, area_t but I'd like to avoid that and be able to define the operator only for the one element of the pair where it is not defined.

    Read the article

  • Trouble creating a SQL query

    - by JoBu1324
    I've been thinking about how to compose this SQL query for a while now, but after thinking about it for a few hours I thought I'd ask the SO community to see if they have any ideas. Here is a mock up of the relevant portion of the tables: contracts id date ar (yes/no) term payments contract_id payment_date The object of the query is to determine, per month, how many payments we expect, vs how many payments we received. conditions for expecting a payment Expected payments begin on contracts.term months after contracts.date, if contracts.ar is "yes". Payments continue to be expected until the month after the first missed payment. There is one other complication to this: payments might be late, but they need to show up as if they were paid on the date expected. The data is all there, but I've been having trouble wrapping my head around the SQL query. I am not an SQL guru - I merely have a decent amount of experience handling simpler queries. I'd like to avoid filtering the results in code, if possible - but without your help that may be what I have to do. Expected Output Month Expected Payments Received Payments January 500 450 February 498 478 March 234 211 April 987 789 ... SQL Fiddle I've created an SQL Fiddle: http://sqlfiddle.com/#!2/a2c3f/2

    Read the article

  • Array indexOf implementation for Internet Explorer

    - by Daemon
    There are plenty of solutions on how to get the indexOf implementation into the Array prototype so that it works under Internet Explorer, however I've stumbled upon an issue that doesn't seem to be addressed anywhere I've looked so far. Using the pretty well agreed upon implementation at MDC, I have the following code that's being problematic now: // indexOf support for IE (from MDC) if (!Array.prototype.indexOf) { Array.prototype.indexOf = function(elt /*, from*/) { var len = this.length >>> 0; var from = Number(arguments[1]) || 0; from = (from < 0) ? Math.ceil(from) : Math.floor(from); if (from < 0) from += len; for (; from < len; from++) { if (from in this && this[from] === elt) return from; } return -1; }; } var i = [1,2,3,4]; for (j in i) { alert(i[j]); } I am expecting to receive 4 alerts, each one containing one of the elements of the array. In Firefox and Chrome, that's exactly what I see, however in IE8 I get an additional alert containing the indexOf function code. What can be done to avoid this?

    Read the article

  • jQuery: Targeting elements added via *non-jQuery* AJAX before any Javascript events fire? Beyond th

    - by peteorpeter
    Working on a Wicket application that adds markup to the DOM after onLoad via Wicket's built-in AJAX for an auto-complete widget. We have an IE6 glitch that means I need to reposition the markup coming in, and I am trying to avoid tampering with the Wicket javascript... blah blah blah... here's what I'm trying to do: New markup arrives in the DOM (I don't have access to a callback) Somehow I know this, so I fire my code. I tried this, hoping the new tags would trigger onLoad events: $("selectorForNewMarkup").live("onLoad", function(){ //using jQuery 1.4.1 //my code }); ...but have become educated that onLoad only fires on the initial page load. Is there another event fired when elements are added to the DOM? Or another way to sense changes to the DOM? Everything I've bumped into on similar issues with new markup additions, they have access to the callback function on .load() or similar, or they have a real javascript event to work with and live() works perfectly. Is this a pipe dream?

    Read the article

  • CFfile -- value is not set to the queried data

    - by user494901
    I have this add user form, it also doubles as a edit user form by querying the data and setting the value="#query.xvalue#". If the user exists (eg, you're editing a user, it loads in the users data from the database. When doing this on the <cffile field it does not load in the data, then when the insert goes to insert data it overrights the database values with a blank string (If a user does not input a new file). How do I avoid this? Code: Form: <br/>Digital Copy<br/> <!--- If null, set a default if not, set the default to database default ---> <cfif len(Trim(certificationsList.cprAdultImage)) EQ 0> <cfinput type="file" required="no" name="cprAdultImage" value="" > <cfelse> File Exists: <cfoutput><a href="#certificationsList.cprAdultImage#">View File</a></cfoutput> <cfinput type="file" required="no" name="cprAdultImage" value="#certificationsList.cprAdultImage#"> </cfif> Form Processor: <!--- Has a file been specificed? ---> <cfif not len(Trim(form.cprAdultImage)) EQ 0> <cffile action="upload" filefield="cprAdultImage" destination="#destination#" nameConflict="makeUnique"> <cfinvokeargument name="cprAdultImage" value="#pathOfFile##cffile.serverFile#"> <cfelse> <cfinvokeargument name="cprAdultImage" value=""> </cfif> CFC ARGS: <cfargument name="cprAdultExp" required="NO"> <cfargument name="cprAdultCompany" type="string" required="no"> <cfargument name="cprAdultImage" type="string" required="no"> <cfargument name="cprAdultOnFile" type="boolean" required="no"> Query: UPDATE mod_StudentCertifications SET cprAdultExp='#DateFormat(ARGUMENTS.cprAdultExp, "mm/dd/yyyy")#', cprAdultCompany='#Trim(ARGUMENTS.cprAdultCompany)#', cprAdultImage='#Trim(ARGUMENTS.cprAdultImage)#', cprAdultOnFile='#Trim(ARGUMENTS.cprAdultOnFile)#' INSERT INTO mod_StudentCertifications( cprAdultExp, cprAdultcompany, cprAdultImage, cprAdultOnFile

    Read the article

  • Dependency injection in constructors

    - by andre
    Hello everyone. I'm starting a new project and setting up the base to work on. A few questions have risen and I'll probably be asking quite a few in here, hopefully I'll find some answers. First step is to handle dependencies for objects. I've decided to go with the dependency injection design pattern, to which I'm somewhat new, to handle all of this for the application. When actually coding it I came across a problem. If a class has multiple dependencies and you want to pass on multiple dependencies via the constructor (so that they cannot be changed after you instantiate the object). How do you do it without passing an array of dependencies, using call_user_func_array(), eval() or Reflection? This is what i'm looking for: <?php class DI { public function getClass($classname) { if(!$this->pool[$classname]) { # Load dependencies $deps = $this->loadDependencies($classname); # Here is where the magic should happen $instance = new $classname($dep1, $dep2, $dep3); # Add to pool $this->pool[$classname] = $instance; return $instance; } else { return $this->pool[$classname]; } } } Again, I would like to avoid the most costly methods to call the class. Any other suggestions?

    Read the article

  • Alternative for table mark-up in ASP.NET not working properly

    - by yetanothercoder
    Using Visual WebDeveloper 2010 Express and ASP.NET 4.0 Don't know whether its relevant but the whole thing is in a ContentPlaceHolder and inside an UpdatePanel. To avoid using the old table tr td model, I have created a simple form like this <div class="admin-form"> <asp:Label ID="UserNameLabel" runat="server" CssClass="form-label" Text="User Name" /> <asp:TextBox ID="UserNameText" runat="server" Width="200px"/> <br /> <asp:Label ID="PasswordLabel" runat="server" CssClass="form-label" Text="Password" /> <asp:TextBox ID="PasswordText" runat="server" TextMode="Password" Width="200px"/> <br /> <asp:Label ID="ConfirmPasswordLabel" runat="server" CssClass="form-label" Text="Confirm Password" /> <asp:TextBox ID="ConfirmPasswordText" runat="server" TextMode="Password" Width="200px"/> <br /> <asp:Label ID="EmailLabel" runat="server" CssClass="form-label" Text="Email" /> <asp:TextBox ID="EmailText" runat="server" Width="200px"/> <br /> <br /> <br /> <span class="form-label"></span> <asp:Button ID="CreateUserButton" runat="server" CssClass="button blue" Text="Create New User"/> </div> And the CSS .form-label { width: 300px !important; } This renders incorrectly as I would like to have all textboxes vertically lined after taking 300px. What is wrong? P.S: I cannot use HTML Controls like label as I have resx for globalization

    Read the article

  • Is unnecessary error handling recommended in business logic? eg. Null check/Percentage limit check etc

    - by novice_at_work
    We usually put unnecessary checks in our business logic to avoid failures. Eg. 1. public ObjectABC funcABC(){ ObjectABC obj = new ObjectABC; .......... .......... //its never set to null here. .......... return obj; } ObjectABC o = funABC(); if(o!=null){ //do something } Why do we need this null check if we are sure that it will never be null? Is it a good practice or not? 2. int pplReached = funA(..,..,..); int totalPpl = funB(..,..,..); funA() just puts a few more restriction over result of funB(). Double percentage = (totalPpl==0||totalPpl<pplReached) ? 0.0 : pplReached/totalPpl; Do we again need this check? The questions is: Aren't we swallowing some fundamental issue by putting such checks? Issues which should be shown ideally, are avoided by putting these checks. What is the recommended way?

    Read the article

  • How to display recently view items in iphone

    - by Pugal Devan
    Hi friends, I have created tab bar and have three views. Tab-1 --> table view and it navigates to detail table view. Tab-2 --> map view. Tab-3 --> table view.(Recent view for Tab-1 items). Now i have displayed the names in the table view in tab-1. The names are changed dynamically and displayed using XML parsing. In tab-3 is the recent view. Now i want to display the details in recent view those who visit recently in tab-1 view. I want to display only 10 items in the recent view. So i have used NSMutableArray and i have set deleagtes due to get the items in recent view from tab-1 view. How to avoid the duplicate recent items and how to remove the older items and inserts the new recent items in recent view. Here my sample code, In Recent view class, stories = [[NSMutableArray alloc] initWithCapacity:10]; items = [[NSMutableDictionary alloc] init]; NSString *preferName = [devDelegate getCurrentAuthor]; //(get name dynamically) [items setObject:preferName forKey:@"preferName"]; [stories addObject:[items copy]]; cell.textLabel.text = [[stories objectAtIndex:storyIndex] objectForKey:@"preferName"]; So please guide me to how to achieve this. Thanks.

    Read the article

  • Progressively stream the output of an ASP.NET page - or render a page outside of an HTTP request

    - by Evgeny
    I have an ASP.NET 2.0 page with many repeating blocks, including a third-party server-side control (so it's not just plain HTML). Each is quite expensive to generate, in terms of both CPU and RAM. I'm currently using a standard Repeater control for this. There are two problems with this simple approach: The entire page must be rendered before any of it is returned to the client, so the user must wait a long time before they see any data. (I write progress messages using Response.Write, so there is feedback, but no actual results.) The ASP.NET worker process must hold everything in memory at the same time. There is no inherent needs for this: once one block is processed it won't be changed, so it could be returned to the client and the memory could be freed. I would like to somehow return these blocks to the client one at a time, as each is generated. I'm thinking of extracting the stuff inside the Repeater into a separate page and getting it repeatedly using AJAX, but there are some complications involved in that and I wonder if there is some simper approach. Ideally I'd like to keep it as one page (from the client's point of view), but return it incrementally. Another way would be to do something similar, but on the server: still create a separate page, but have the server access it and then Response.Write() the HTML it gets to the response stream for the real client request. Is there a way to avoid an HTTP request here, though? Is there some ASP.NET method that would render a UserControl or a Page outside of an HTTP request and simply return the HTML to me as a string? I'm open to other ideas on how to do this as well.

    Read the article

  • Ember Data Sycn - LocalStorage+REST+RealTime+Online/Offline

    - by Miguel Madero
    We have a combination of requirements in terms o data access. Pre-load some reference data. We need reference data to survive browser restarts instead of just living in memory to avoid loading it all the time. I'm currently using the LocalStorageAdapter for that. Once we have it, we would like to sync changes (polling or using Socket.IO in the background and updating the LocalStorage could do the trick) There're other models that are more transactional, where we would need to directly go to the Server and get/save them. It would be nice to use something like the RESTAdapter for that. Lastly, there're some operations that should work off-line and changes should be synced later. To make it more concrete: * We pre-load vendor and "favorite products" into Local Storage. We work offline with those. * We need to sync server changes to vendor and product information. * If they search the full catalog, that requires them to be online. * When offline, we need to allow users to add something to their cart or even submit and order. We would like to queue this action and submit it when they have an Internet Connection. So a few questions are derived from this: * Is there a way to user RESTAdapter in combination with LocalStorage? * Is there some Socket.IO support? (Happy to do this part manually) * Is there Queueing support? Ideally at the Ember-Data level. I know we will have to do a lot of this manually and pull together the different lego pieces, but I wanted to ask for some perspective from experience Ember devs.

    Read the article

  • Why is using a common-lookup table to restrict the status of entity wrong?

    - by FreshCode
    According to Five Simple Database Design Errors You Should Avoid by Anith Sen, using a common-lookup table to store the possible statuses for an entity is a common mistake. Why is this wrong? I disagree that it's wrong, citing the example of jobs at a repair service with many possible statuses that generally have a natural flow, eg.: Booked In Assigned to Technician Diagnosing problem Waiting for Client Confirmation Repaired & Ready for Pickup Repaired & Couriered Irreparable & Ready for Pickup Quote Rejected Arguably, some of these statuses can be normalised to tables like Couriered Items, Completed Jobs and Quotes (with Pending/Accepted/Rejected statuses), but that feels like unnecessary schema complication. Another common example would be order statuses that restrict the status of an order, eg: Pending Completed Shipped Cancelled Refunded The status titles and descriptions are in one place for editing and are easy to scaffold as a drop-down with a foreign key for dynamic data applications. This has worked well for me in the past. If the business rules dictate the creation of a new order status, I can just add it to OrderStatus table, without rebuilding my code.

    Read the article

  • Threshold of blurry image - part 2

    - by 1''
    How can I threshold this blurry image to make the digits as clear as possible? In a previous post, I tried adaptively thresholding a blurry image (left), which resulted in distorted and disconnected digits (right): Since then, I've tried using a morphological closing operation as described in this post to make the brightness of the image uniform: If I adaptively threshold this image, I don't get significantly better results. However, because the brightness is approximately uniform, I can now use an ordinary threshold: This is a lot better than before, but I have two problems: I had to manually choose the threshold value. Although the closing operation results in uniform brightness, the level of brightness might be different for other images. Different parts of the image would do better with slight variations in the threshold level. For instance, the 9 and 7 in the top left come out partially faded and should have a lower threshold, while some of the 6s have fused into 8s and should have a higher threshold. I thought that going back to an adaptive threshold, but with a very large block size (1/9th of the image) would solve both problems. Instead, I end up with a weird "halo effect" where the centre of the image is a lot brighter, but the edges are about the same as the normally-thresholded image: Edit: remi suggested morphologically opening the thresholded image at the top right of this post. This doesn't work too well. Using elliptical kernels, only a 3x3 is small enough to avoid obliterating the image entirely, and even then there are significant breakages in the digits:

    Read the article

  • problem configure JBoss to work with JNDI(2)

    - by Spiderman
    in continuation to the question from last week: http://stackoverflow.com/questions/2828237/problem-configure-jboss-to-work-with-jndi I'm trying to bind datasource in JBoss and use it in my application. In my struggling, I already managed to avoid the javax.naming.NameNotFoundException by: 1. using in java new InitialContext().lookup(connection); instead of new JndiObjectFactoryBean().setJndiName(connection); 2. changing the connection name from: 'jndi-name' to 'java:jndi-name' Now the problem is that the datasouce that I get from the lookup is null. I created the datsource file: <datasources> <local-tx-datasource> <jndi-name>bilby</jndi-name> <connection-url>jdbc:oracle:myURL</connection-url> <driver-class>oracle.jdbc.OracleDriver </driver-class> <user-name>myUsername</user-name> <password>myPassword</password> <exception-sorter-class- name>org.jboss.resource.adapter.jdbc.vendor.OracleExceptionSorter</exception-sorter-class-name> <metadata> <type-mapping>Oracle9i</type-mapping> </metadata> </local-tx-datasource> </datasources> and put it under \server\default\deploy\oracle-ds.xml I get during runtime the line: 18:37:56,560 INFO [ConnectionFactoryBindingService] Bound ConnectionManager 'jb oss.jca:service=DataSourceBinding,name=bilby' to JNDI name 'java:bilby' So my question is - why do I get null as my datasource???

    Read the article

  • Javascript problem with iframe that's hidden before loaded

    - by Aistina
    I have a page that contains an iframe that gets loaded using Javascript: index.html <iframe id="myFrame" width="800" height="600" style="display: none;"></iframe> <div id="loader"><!-- some loading indicator --></div> <script type="text/javascript"> function someFunction() { var myFrame = document.getElementById('myFrame'); var loader = document.getElementById('loader'); loader.style.display = 'block'; myFrame.src = 'myFrame.html'; myFrame.onload = function() { myFrame.style.display = 'block'; loader.style.display = 'none'; }; } </script> The page that gets loaded in the iframe contains some Javascript logic which calculates the sizes of certain elements for the purposes of adding a JS driven scrollbar (jScrollPane + jQuery Dimensions). myFrame.html <div id="scrollingElement" style="overflow: auto;"> <div id="several"></div> <div id="child"></div> <div id="elements"></div> </div> <script type="text/javascript"> $(document).load(function() { $('#scrollingElement').jScrollPane(); }); </script> This works in Chrome (and probably other Webkit browsers), but fails in Firefox and IE because at the time jScrollPane gets called, all the elements are still invisble and jQuery Dimensions is unable to determine any element's dimensions. Is there a way to make sure my iframe is visible before $(document).ready(...) gets called? Other than using setTimeout to delay jScrollPane, which is something I definitely want to avoid.

    Read the article

  • Spring MVC 3.0 Rest problem

    - by Gidogeek
    Hi Guys, I'm trying out Spring MVC 3.0 for the first time and like to make it RESTfull. This is my controller: @Controller @RequestMapping(value = "/product") @SessionAttributes("product") public class ProductController { @Autowired private ProductService productService; public void setProductValidator(ProductValidator productValidator, ProductService productService) { this.productService = productService; } @RequestMapping(method = RequestMethod.GET) public Product create() { //model.addAttribute(new Product()); return new Product(); } @RequestMapping(method = RequestMethod.POST) public String create(@Valid Product product, BindingResult result) { if (result.hasErrors()) { return "product/create"; } productService.add(product); return "redirect:/product/show/" + product.getId(); } @RequestMapping(value = "/show/{id}", method = RequestMethod.GET) public Product show(@PathVariable int id) { Product product = productService.getProductWithID(id); if (product == null) { //throw new ResourceNotFoundException(id); } return product; } @RequestMapping(method = RequestMethod.GET) public List<Product> list() { return productService.getProducts(); } } I have 2 questions about this. I'm a believer in Convention over Configuration and therefor my views are in jsp/product/ folder and are called create.jsp , list.jsp and show.jsp this works relatively well until I add the @PathVariable attribute. When I hit root/product/show/1 I get the following error: ../jsp/product/show/1.jsp" not found how do I tell this method to use the show.jsp view ? If I don't add the RequestMapping on class level my show method will be mapped to root/show instead of root/owner/show how do I solve this ? I'd like to avoid using the class level RequestMapping.

    Read the article

  • Measuring time spent in application / thread

    - by Adamski
    I am writing a simulation in Java whereby objects act under Newtonian physics. An object may have a force applied to it and the resulting velocity causes it to move across the screen. The nature of the simulation means that objects move in discrete steps depending on the time ellapsed between the current and previous iteration of the animation loop; e.g public void animationLoop() { long prev = System.currentTimeMillis(); long now; while(true) { long now = System.currentTimeMillis(); long deltaMillis = now - prev; prev = now; if (deltaMillis > 0) { // Some time has passed for (Mass m : masses) { m.updatePosition(deltaMillis); } // Do all repaints. } } } A problem arises if the animation thread is delayed in some way causing a large amount of time to ellapse (the classic case being under Windows whereby clicking and holding on minimise / maximise prevents a repaint), which causes objects to move at an alarming rate. My question: Is there a way to determine the time spent in the animation thread rather than the wallclock time, or can anyone suggest a workaround to avoid this problem? My only thought so far is to contstrain deltaMillis by some upper bound.

    Read the article

  • Load PEM encoded private RSA key in Crypto++

    - by 01100110
    Often times, user will have PEM encoded RSA private keys. Crypto++ requires that these keys be in DER format to load. I've been asking people to manually convert their PEM files to DER beforehand using openssl like this: openssl pkcs8 -in in_file.pem -out out_file.der -topk8 -nocrypt -outform der That works fine, but some people don't understand how to do that nor do they want to. So I would like to convert PEM files to DER files automatically within the program. Is it as simple as striping the "-----BEGIN CERTIFICATE-----" and "-----END CERTIFICATE-----" from the PEM or is some other transformation required as well? I've been told that between those markers that it's just b64 encoded DER. Here's some code that demonstrates the issue: // load the private key CryptoPP::RSA::PrivateKey PK; CryptoPP::ByteQueue bytes; try { CryptoPP::FileSource File( rsa.c_str(), true, new CryptoPP::Base64Decoder() ); File.TransferTo( bytes ); bytes.MessageEnd(); // This line Causes BERDecodeError when a PEM encoded file is used PK.Load( bytes ); } catch ( CryptoPP::BERDecodeErr ) { // Convert PEM to DER and try to load the key again } I'd like to avoid making system calls to openssl and do the transformation entirely in Crypto++ so that users can provide either format and things "just work". Thanks for any advice.

    Read the article

  • Visitor Pattern can be replaced with Callback functions?

    - by getit
    Is there any significant benefit to using either technique? In case there are variations, the Visitor Pattern I mean is this: http://en.wikipedia.org/wiki/Visitor_pattern And below is an example of using a delegate to achieve the same effect (at least I think it is the same) Say there is a collection of nested elements: Schools contain Departments which contain Students Instead of using the Visitor pattern to perform something on each collection item, why not use a simple callback (Action delegate in C#) Say something like this class Department { List Students; } class School { List Departments; VisitStudents(Action<Student> actionDelegate) { foreach(var dep in this.Departments) { foreach(var stu in dep.Students) { actionDelegate(stu); } } } } School A = new School(); ...//populate collections A.Visit((student)=> { ...Do Something with student... }); *EDIT Example with delegate accepting multiple params Say I wanted to pass both the student and department, I could modify the Action definition like so: Action class School { List Departments; VisitStudents(Action<Student, Department> actionDelegate, Action<Department> d2) { foreach(var dep in this.Departments) { d2(dep); //This performs a different process. //Using Visitor pattern would avoid having to keep adding new delegates. //This looks like the main benefit so far foreach(var stu in dep.Students) { actionDelegate(stu, dep); } } } }

    Read the article

  • Custom Android control with children

    - by Gromix
    Hi, I'm trying to create a custom Android control that contains a LinearLayout. You can think of it as an extended LinearLayout with fancy borders, a background, an image on the left... I could do it all in XML (works great) but since I have dozens of occurences in my app it's getting hard to maintain. I thought it would be nicer to have something like this: /* Main.xml */ <MyFancyLayout> <TextView /> /* what goes inside my control's linear layout */ </MyfancyLayout> How would you approach this? I'd like to avoid re-writing the whole linear layout onMeasure / onLayout methods. This is what I have for the moment: /* MyFancyLayout.xml */ <TableLayout> <ImageView /> <LinearLayout id="container" /> /* where I want the real content to go */ </TableLayout> and /* MyFancyLayout.java */ public class MyFancyLayout extends LinearLayout { public MyFancyLayout(Context context) { super(context); View.inflate(context, R.layout.my_fancy_layout, this); } } How would you go about inserting the user-specified content (the TextView in main.xml) in the right place (id=container)? Cheers! Romain ----- edit ------- Still no luck on this, so I changed my design to use a simpler layout and decided to live with a bit of repeated XML. Still very interested in anyone knows how to do this though!

    Read the article

  • JTable data only shown after scrolling

    - by Christian 'fuzi' Orgler
    I wrote a method, that creates my DefaultTableModel and there I'm going to add my records. When I set the model to my JTable, the data rows are blank. After scrolling the data gets displayed correct. How can I avoid this and display the data from the first moment? EDIT: I imported the javax.swing.table.DefaultTableModel -- is this correct? private DefaultTableModel _dtm; private void loadTable(Vector<Member> members) { loadTableModel(); try { lbl_state.setText("Please wait"); for (Member actMember : members) { String gender = ""; if (actMember.getGender() == MemberView.MEMBER_MALE) { gender = "männlich"; } else { gender = "weiblich"; } _dtm.addRow(new Object[]{ actMember.getNname(), actMember.getVname(), actMember.getCity(), actMember.getStreet(), actMember.getPlz(), actMember.getMail(), actMember.getPhonenumber(), actMember.getBirthdayString(), actMember.getStartDateString(), gender, actMember.getBankname(), actMember.getAccountnumber(), actMember.getBanknumber(), actMember.getGroup().toString(), (actMember.hasAccess() ? "JA" : "NEIN"), actMember.getWriteDateString(), (actMember.hasDrinkAbo() ? "JA" : "NEIN") }); } } catch (Exception ex) { System.err.println(ex.getMessage()); } tbl_results.setModel(_dtm); } private void loadTableModel() { _dtm = new DefaultTableModel(new Object[]{"Nachname", "Vorname", "Ort", "Straße", "PLZ", "E-Mail", "Telefon", "Geburtsdatum", "Beitrittsdatum", "Geschlecht", "Bankname", "Kontonummer", "Bankleitzahl", "Gruppe", "hat Zugriff", "Einschreibdatum", "Getränkeabo"}, 0); tbl_results.setAutoResizeMode(JTable.AUTO_RESIZE_ALL_COLUMNS); }

    Read the article

  • Database schema for a library

    - by ABach
    Hi all - I'm designing a library management system for a department at my university and I wanted to enlist your eyes on my proposed schema. This post is primarily concerned with how we store multiple copies of each book; something about what I've designed rubs me the wrong way, and I'm hoping you all can point out better ways to tackle things. For dealing with users checking out books, I've devised three tables: book, customer, and book_copy. The relationships between these tables are as follows: Every book has many book_copies (to avoid duplicating the book's information while storing the fact that we have multiple copies of that book). Every user has many book_copies (the other end of the relationship) The tables themselves are designed like this: ------------------------------------------------ book ------------------------------------------------ + id + title + author + isbn + etc. ------------------------------------------------ ------------------------------------------------ customer ------------------------------------------------ + id + first_name + first_name + email + address + city + state + zip + etc. ------------------------------------------------ ------------------------------------------------ book_copy ------------------------------------------------ + id + book_id (FK to book) + customer_id (FK to customer) + checked_out + due_date + etc. ------------------------------------------------ Something about this seems incorrect (or at least inefficient to me) - the perfectionist in me feels like I'm not normalizing this data correctly. What say ye? Is there a better, more effective way to design this schema? Thanks!

    Read the article

  • Export large amount of data from Oracle 10G to SQL Server 2005

    - by uniball
    Dear all, I need to export 100 million data rows (avg row length ~ 100 bytes) from Oracle 10G database table into SQL server (over WAN/VLAN with 6MBits/sec capacity) on a regular basis. So far, these are the options that I have tried and a quick summary. Has anyone tried this before? Are there other better options? Which option would be the best in terms of performance and reliability? The time taken has been calculated using tests on smaller amounts of data and then extrapolating it to estimate the time required. Using data import wizard on the SQL server or SSIS packages to import the data. It will take around 150 hours to complete the task. Using Oracle batch job to spool data into a comma-delimited flat-file. Then using SSIS package to FTP this file to the SQL server and then load directly from the flat-file. The issue here is the size of the flat-file which is expected to run in GBs. Although this option is drastically different, I am even considering the option of using Linked Server to query the Oracle data directly at run-time to avoid bringing in data. Performance is a big problem and I have limited control over the Oracle database in terms of creating table indexes. Regards, Uniball

    Read the article

< Previous Page | 479 480 481 482 483 484 485 486 487 488 489 490  | Next Page >