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• Appropriate wx.Sizer(s) for the job?

  - by MetaHyperBolic

  I have a space in which I would like certain elements (represented here by A, B, D, and G) to each be in its own "corner" of the design. The corners ought to line up as if each of the four elements was repelling the other; a rectangle. This is to be contained within an unresizable panel. I will have several similar panels and want to keep the location of the elements as identical as possible. (I needed something a little more complex than a wx.Wizard, but with the same general idea.) AAAAAAAAAA BB CCCCCCCCCCCCCCCCCC CCCCCCCCCCCCCCCCCC CCCCCCCCCCCCCCCC CCCCCCCCCCCCCC CCCCCCCCCCCCCCCCCC CCCCCCCCCCCCCCCC CCCCCCCCCCCCCCCCCC DDD EEE FFF GGG A represents a text in a large font. B represents a numeric progress meter (e.g. "1 of 7") in a small font. C represents a large block of text. D, E, F, and G are buttons. The G button is separated from others for functionality. I have attempted nested wx.BoxSizers (horizontal boxes inside of one vertical box) without luck. My first problem with wx.BoxSizer is that the .SetMinSize on my last row has not been honored. The second problem is that I have no idea how to make the G button "take up space" without growing comically large, or how I can jam it up against the right edge and bottom edge. I have tried to use a wx.GridBagSizer, but ran into entirely different issues. After plowing through the various online tutorials and wxPython in Action, I'm a little frustrated. The relevant forums appear to see activity once every two weeks. "Playing around with it" has gotten me nowhere; I feel as if I am trying to smooth out a hump in ill-laid carpet.

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• How large a role does subjectiveness play in programming?

  - by Bob

  I often read about the importance of readability and maintainability. Or, I read very strong opinions about which syntax features are bad or good. Or discussions about the values of certain paradigms, like OOP. Aside from that, this same question floats about in my mind whenever I read debates on SO or Meta about subjective questions. Or read questions about best practices and sometimes find myself or others disagreeing. What role does subjectiveness play within the programming realm? Sometimes I think it plays a large role. Software developers are engineers in a way, but also people. A large part of programming is dealing with code that's human readable. This is very different from Math or Physics or other disciplines with very exact and structured rules. Here the exact structure and rules are largely up in the air, changeable on a whim, and hence the amount of languages in existence. And one person may find one language very readable, and another person may find their own language the most comforting. The same with practices. One person may not like certain accepted practices. I myself find splitting classes into different files very unreadable, for instance. But, I can't say rules haven't helped in general. Certain practices have and do make life easier. And new languages have given rise to syntax and structure that make life easier. There's certainly been a progression towards code that is easier to read and maintain even given a largely diverse group of people. So maybe these things aren't as subjective as I thought. It reminds me, in a way, of UI design. Certainly it's subjective, but then there's an entire discipline involved in crafting good UI and it tends to work. Is there something non-subjective about the ideas behind maintainability, readability, and other best practices? Is there something tangible to grasp when one develops a new language or thinks of new practices?

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• Good mobile oriented GWT widget library alternatives

  - by Michael Donohue

  I've been developing a travel planning site - tripgrep.com - which is built on appengine, GWT and smartgwt, among other technologies. It is still early days, and the site is now working well on my development environment, which is either a windows or mac computer. However, I am frequently talking up the website to my friends when we are at a bar or other venue, so I am standing there while they try to access the site via an iPhone, Android or Blackberry - I've witnessed all three. It has been painfully obvious that the browser based frontend takes a long time to download on a mobile device. I am pretty sure this is because of the javascript download for SmartGWT. So, I would like to look at alternatives to SmartGWT. What I like about SmartGWT is that it has a reasonable look and feel out of the box - I don't need to learn any design or css and it has an office application look. This is considerably better than the GWT built-in widgets, which just get a blue border. The better look-and-feel is why I went with SmartGWT early on. However, the slow load times are killing me on these mobile demos. So now I want a fast loading widget alternative that has good look-and-feel out of the box. The features I care about are: tabs, good form layout, Google maps API integration, grid data viewing. If those are all available in a library that loads quickly on a mobile device, then that's the library I want.

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• Is there a good way to QuickCheck Happstack.State methods?

  - by Paul Kuliniewicz

  I have a set of Happstack.State MACID methods that I want to test using QuickCheck, but I'm having trouble figuring out the most elegant way to accomplish that. The problems I'm running into are: The only way to evaluate an Ev monad computation is in the IO monad via query or update. There's no way to create a purely in-memory MACID store; this is by design. Therefore, running things in the IO monad means there are temporary files to clean up after each test. There's no way to initialize a new MACID store except with the initialValue for the state; it can't be generated via Arbitrary unless I expose an access method that replaces the state wholesale. Working around all of the above means writing methods that only use features of MonadReader or MonadState (and running the test inside Reader or State instead of Ev. This means forgoing the use of getRandom or getEventClockTime and the like inside the method definitions. The only options I can see are: Run the methods in a throw-away on-disk MACID store, cleaning up after each test and settling for starting from initialValue each time. Write the methods to have most of the code run in a MonadReader or MonadState (which is more easily testable), and rely on a small amount of non-QuickCheck-able glue around it that calls getRandom or getEventClockTime as necessary. Is there a better solution that I'm overlooking?

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• Absolutely positioned div on right causing scrollbar when the left doesn't

  - by Michael Snyder

  I'm trying to "flank" a centered div with some design elements that are absolutely positioned outside the main div's width. I'm getting a scroll bar due to the element on the right, but not the element on the left (IE6/7/8, Chrome, Firefox). How can I get rid of that horizontal scrollbar? <html> <head> <style type="text/css"> html, body { height: 100%; width: 100%; margin: 0; } body { text-align: center; } .wrapper { margin: 0 auto; position: relative; width: 960px; z-index: 0; } .main { background: #900; height: 700px; } .right, .left { position: absolute; height: 100px; width: 100px; } .right { background: #090; top: 0px; left: 960px; z-index: 1; } .left { background: #009; top: 0px; left: -100px; z-index: 1; } </style> </head> <body> <div class="wrapper"> <div class="main"></div> <div class="left"></div> <div class="right"></div> </div> </body> </html>

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• Why put a DAO layer over a persistence layer (like JDO or Hibernate)

  - by Todd Owen

  Data Access Objects (DAOs) are a common design pattern, and recommended by Sun. But the earliest examples of Java DAOs interacted directly with relational databases -- they were, in essence, doing object-relational mapping (ORM). Nowadays, I see DAOs on top of mature ORM frameworks like JDO and Hibernate, and I wonder if that is really a good idea. I am developing a web service using JDO as the persistence layer, and am considering whether or not to introduce DAOs. I foresee a problem when dealing with a particular class which contains a map of other objects: public class Book { // Book description in various languages, indexed by ISO language codes private Map<String,BookDescription> descriptions; } JDO is clever enough to map this to a foreign key constraint between the "BOOKS" and "BOOKDESCRIPTIONS" tables. It transparently loads the BookDescription objects (using lazy loading, I believe), and persists them when the Book object is persisted. If I was to introduce a "data access layer" and write a class like BookDao, and encapsulate all the JDO code within this, then wouldn't this JDO's transparent loading of the child objects be circumventing the data access layer? For consistency, shouldn't all the BookDescription objects be loaded and persisted via some BookDescriptionDao object (or BookDao.loadDescription method)? Yet refactoring in that way would make manipulating the model needlessly complicated. So my question is, what's wrong with calling JDO (or Hibernate, or whatever ORM you fancy) directly in the business layer? Its syntax is already quite concise, and it is datastore-agnostic. What is the advantage, if any, of encapsulating it in Data Access Objects?

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• Dynamically created controls and the ASP.NET page lifecycle

  - by Dirk

  I'm working on an ASP.NET project in which the vast majority of the forms are generated dynamically at run time (form definitions are stored in a DB for customizability). Therefore, I have to dynamically create and add my controls to the Page every time OnLoad fires, regardless of IsPostBack. This has been working just fine and .NET takes care of managing ViewState for these controls. protected override void OnLoad(EventArgs e) { base.OnLoad(e); RenderDynamicControls() } private void RenderDynamicControls(){ //1. call service layer to retrieve form definition //2. create and add controls to page container } I have a new requirement in which if a user clicks on a given button (this button is created at design time) the page should be re-rendered in a slightly different way. So in addition to the code that executes in OnLoad (i.e. RenderDynamicControls()), I have this code: protected void MyButton_Click(object sender, EventArgs e) { RenderDynamicControlsALittleDifferently() } private void RenderDynamicControlsALittleDifferently() (){ //1. clear all controls from the page container added in RenderDynamicControls() //2. call service layer to retrieve form definition //3. create and add controls to page container } My question is, is this really the only way to accomplish what I'm after? It seems beyond hacky to effectively render the form twice simply to respond to a button click. I gather from my research that this is simply how the page-lifecycle works in ASP.NET: Namely, that OnLoad must fire on every Postback before child events are invoked. Still, it's worthwhile to check with the SO community before having to drink the kool-aid. On a related note, once I get this feature completed, I'm planning on throwing an UpdatePanel on the page to perform the page updates via Ajax. Any code/advice that make that transition easier would be much appreciated. Thanks

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• Java method keyword "final" and its use

  - by Lukas Eder

  When I create complex type hierarchies (several levels, several types per level), I like to use the final keyword on methods implementing some interface declaration. An example: interface Garble { int zork(); } interface Gnarf extends Garble { /** * This is the same as calling {@link #zblah(0)} */ int zblah(); int zblah(int defaultZblah); } And then abstract class AbstractGarble implements Garble { @Override public final int zork() { ... } } abstract class AbstractGnarf extends AbstractGarble implements Gnarf { // Here I absolutely want to fix the default behaviour of zblah // No Gnarf shouldn't be allowed to set 1 as the default, for instance @Override public final int zblah() { return zblah(0); } // This method is not implemented here, but in a subclass @Override public abstract int zblah(int defaultZblah); } I do this for several reasons: It helps me develop the type hierarchy. When I add a class to the hierarchy, it is very clear, what methods I have to implement, and what methods I may not override (in case I forgot the details about the hierarchy) I think overriding concrete stuff is bad according to design principles and patterns, such as the template method pattern. I don't want other developers or my users do it. So the final keyword works perfectly for me. My question is: Why is it used so rarely in the wild? Can you show me some examples / reasons where final (in a similar case to mine) would be very bad?

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• Python - Open default mail client using mailto, with multiple recipients

  - by victorhooi

  Hi, I'm attempting to write a Python function to send an email to a list of users, using the default installed mail client. I want to open the email client, and give the user the opportunity to edit the list of users or the email body. I did some searching, and according to here: http://www.sightspecific.com/~mosh/WWW_FAQ/multrec.html It's apparently against the RFC spec to put multiple comma-delimited recipients in a mailto link. However, that's the way everybody else seems to be doing it. What exactly is the modern stance on this? Anyhow, I found the following two sites: http://2ality.blogspot.com/2009/02/generate-emails-with-mailto-urls-and.html http://www.megasolutions.net/python/invoke-users-standard-mail-client-64348.aspx which seem to suggest solutions using urllib.parse (url.parse.quote for me), and webbrowser.open. I tried the sample code from the first link (2ality.blogspot.com), and that worked fine, and opened my default mail client. However, when I try to use the code in my own module, it seems to open up my default browser, for some weird reason. No funny text in the address bar, it just opens up the browser. The email_incorrect_phone_numbers() function is in the Employees class, which contains a dictionary (employee_dict) of Employee objects, which themselves have a number of employee attributes (sn, givenName, mail etc.). Full code is actually here (http://stackoverflow.com/questions/2963975/python-converting-csv-to-objects-code-design) from urllib.parse import quote import webbrowser .... def email_incorrect_phone_numbers(self): email_list = [] for employee in self.employee_dict.values(): if not PhoneNumberFormats.standard_format.search(employee.telephoneNumber): print(employee.telephoneNumber, employee.sn, employee.givenName, employee.mail) email_list.append(employee.mail) recipients = ', '.join(email_list) webbrowser.open("mailto:%s?subject=%s&body=%s" % (recipients, quote("testing"), quote('testing')) ) Any suggestions? Cheers, Victor

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• dynamically created controls and responding to control events

  - by Dirk

  I'm working on an ASP.NET project in which the vast majority of the forms are generated dynamically at run time (form definitions are stored in a DB for customizability). Therefore, I have to dynamically create and add my controls to the Page every time OnLoad fires, regardless of IsPostBack. This has been working just fine and .NET takes care of managing ViewState for these controls. protected override void OnLoad(EventArgs e) { base.OnLoad(e); RenderDynamicControls() } private void RenderDynamicControls(){ //1. call service layer to retrieve form definition //2. create and add controls to page container } I have a new requirement in which if a user clicks on a given button (this button is created at design time) the page should be re-rendered in a slightly different way. So in addition to the code that executes in OnLoad (i.e. RenderDynamicControls()), I have this code: protected void MyButton_Click(object sender, EventArgs e) { RenderDynamicControlsALittleDifferently() } private void RenderDynamicControlsALittleDifferently() (){ //1. clear all controls from the page container added in RenderDynamicControls() //2. call service layer to retrieve form definition //3. create and add controls to page container } My question is, is this really the only way to accomplish what I'm after? It seems beyond hacky to effectively render the form twice simply to respond to a button click. I gather from my research that this is simply how the page-lifecycle works in ASP.NET: Namely, that OnLoad must fire on every Postback before child events are invoked. Still, it's worthwhile to check with the SO community before having to drink the kool-aid. On a related note, once I get this feature completed, I'm planning on throwing an UpdatePanel on the page to perform the page updates via Ajax. Any code/advice that make that transition easier would be much appreciated. Thanks

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• Should I remove all inheritance from my model in order to work with ria services?

  - by TimothyP

  I've posted some questions on this before, but it's different. So consider a small portion of our model: Person Customer Employee Spouse Person is the base class which has 3 classes that inherit from it. These 4 are very central in our design and link to many other entities. I could solve all the problems I'm experiencing with ria-services by removing the inheritance but that would really increase the complexety of the model. The first problem I experienced was that I couldn't query for Customers, Employees or Spouses, but someone gave me a solution, which was to add something like this to the DomainService: public IQueryable<Employee> GetEmployees() { return this.ObjectContext.People.OfType<Employee>(); } public IQueryable<Customer> GetCustomers() { return this.ObjectContext.People.OfType<Customer>(); } public IQueryable<Spouse> GetSpouses() { return this.ObjectContext.People.OfType<Spouse>(); } Next I tried something that seemed very normal to me: var employee = new Employee() { //.... left out to reduce the length of this question }; var spouse = new Spouse() { //.... left out to reduce the length of this questions }; employee.Spouse = spouse; context.People.Add(spouse); context.People.Add(employee); context.SubmitChanges(); Then I get the following exception: Cannot retrieve an entity set for the derived entity type 'Spouse'. Use EntityContainer.GetEntitySet(Type) to get the entity set for the base entity type 'Person'. Even when the spouse is already in the database, and I retreive it first I get similar exceptions. Also note that for some reason in some places "Persons" is used instead of "People"... So how do I solve this problem, what am I doing wrong and will I keep running into walls when using ria services with inheritance? I found some references on the web, all saying it works and then some DomainService code in which they suposedly changed something but no details... I'm using VS2010 RC1 + Silveright 4

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• .NET WebBrowser control with Adobe SVG Viewer

  I'm having problems with SVG files loading in a .NET 2.0 WebBrowser control. If I create a new WinForms application project, drag a WebBrowser control and a button onto the Form1.cs design surface, and add a line to the button's on-click handler to set the Url property of the WebBrowser control to an SVG file, I get two IE script errors at runtime (as in, the dialog you get when there is a Javascript problem). The only line of code I'm writing is therefore: webBrowser1.Url = new Uri(@"http://wiki.allegro.cc/pub/f/fb/Grozilla.svg"); This SVG file loads fine if I browse directly to the link with IE; the errors I get via my test app are: line 2, char 1, error: Invalid character, followed by line 1, char 1, error: Object expected (assuming I answer yes to the prompt to 'continue running scripts on this page'). I'm using IE 7.0.5730.13, Adobe SVG Viewer 3.03 build 94, Visual Studio 2008. Can anyone replicate this? Has anyone seen it/got any idea how to fix it? (edit: previously setting the URL in the constructor for the purposes of the example, but this raised the question of whether or not the control had finished initialising, so have changed the example to use a button - the problem still occurs. This bug originally appeared in production code so the example program I wrote was an attempt to isolate the issue and reproduce it as simply as possible.) (edit 2: having tested on several different machines, this problems seems to be related to IE7 - run IE6, and everything works fine.)

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• Is there stl and utf8 friendly C++ Wrapper for ICU, or other powerful unicode library

  - by artyom

  Hello, I need a good Unicode library for C++. I need Transformations in Unicode sensitive way. For example sort all strings in case insensitive way and get their first characters for index. Convert to upper and to lower various Unicode strings. Split text in reasonable position -- words that would work for Chinese and Japanese as well. Formatting numbers, dates in locale sensitive way (should be thread safe). Transparent support of utf8 (primary internal representation). As far as I know the best library is ICU. However, I can't find normal developer friendly API documentation with examples. Also as far as I see, it is not too friendly with modern C++ design, work with STL and so on. Like this std::string msg; unistring umsg.from_utf8(msg); unistring::word_iterator wi; for(wi=umsg.words().begin(),n=0;wi!=usmg.words().wi_end(),n<10;++wi,++n) ; msg=umsg.substr(umsg.words().begin(),wi).to_utf8(); cout<<_("Five 10 words are ")<<msg; Does anybody know good STL friendly ICU wrapper released under Open Source license preferred permissive like MIT or Boost, but others LGPLv2 compatible are ok as well. Is there another high quality library similar to ICU? Platform: UNIX/POSIX, Windows support is not required. Thanks, Artyom Edit: Unfortunatly I wasn't logged in so I can't make asnver accepted... I had attached the ansver by myself.

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• How do I bind an iTunes style source list to an NSTableView using Core Data?

  - by Austin

  I have an iTunes style interface in my application: Source list (NSOutlineView) on the left that contains different libraries and playlists with an NSTableView on the right side of the interface displaying information for "Presentations". Similar to iTunes, I am showing the same type of information in the table view whether a library or playlist is selected (title, author, date created, etc). I currently have an NSArrayController connected to my NSTableView and was setting the fetch predicate based on what was selected in the source list. This works fine when selecting a library because I can just set the fetch predicate to filter by the "type" field in my Presentation Core Data entity. When I try to adjust the fetch predicate for the playlist however, it doesn't look like there is any way to set the fetch predicate because I've got a table in between Playlists and Presentations to keep up with the order within the Playlist. According to the Apple docs, these type of predicates are not doable with Core Data (it basically doesn't multiple inner joins). Below is the relevant portion of my Data Model. Is my data model setup incorrectly? Should I drop the NSArrayController and handle connecting the NSTableView up by hand? I'm trying to figure out if there is a simple fix, or really a design flaw.

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• Should frontend and backend handled by different controllers?

  - by DR

  In my previous learning projects I always used a single controller, but know I wonder if that is good practice or even always possible. In all RESTful Rails tutorials the controllers have a show, an edit and an index view. If an authorized user is logged on, the edit view becomes available and the index view shows additional data manipulation controls, like a delete button or a link to the edit view. Now I have a Rails application which falls exactly into this pattern, but the index view is not reusable: The normal user sees a flashy index page with lots of pictures, complex layout, no Javascript requirement, ... The Admin user index has a completly different minimalistic design, jQuery table and lots of additional data, ... Now I'm not sure how to handle this case. I can think of the following: Single controller, single view: The view is split into two large blocks/partials using an if statement. Single controller, two views: index and index_admin. Two different controllers: BookController and BookAdminController None of this solutions seems perfect, but for now I'm inclined to use the 3rd option. What's the preferred way to do this?

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• Visual Studio 2010 / ASP.NET MVC / Publish

  - by SevenCentral

  I just did a clean install on Windows 7 x64 Professional with the final release of Visual Studio 2010 Premium. In order to duplicate what I'm experiencing do the following in: Create a new ASP.NET MVC 2 Web Application Right click the project and select Properties On the Web tab, select "Use Local IIS Web Server" Click on Create Virtual Directory Save all Unload the project Edit the project file Change MvcBuildViews to true Save all Reload project Right click the project and select Publish Choose the file system publish method Enter a target location Choose Delete all existing files Select Publish Right click the project Select Publish Each time I do the above I get the following errror: "It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level..." The error originates from obj\debug\package\packagetmp\web.config, relative to the project directory. I can repeat this all day long with any MVC 2 project I've built. In order to fix this problem, I need to set MvcBuildViews to false in the project file. That's not really an option. This wasn't a problem in Visual Studio 2008 and it seems to be an issue with the way the Publish command stages files beneath the project directory. Can anyone else duplicate this error? Is this a bug or by design? Is there a fix, workaround, etc...? Thanks.

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• Java generic Comparable where subclasses can't compare to eachother

  - by dege

  public abstract class MyAbs implements Comparable<MyAbs> This would work but then I would be able to compare class A and B with each other if they both extend MyAbs. What I want to accomplish however is the exact opposite. So does anyone know a way to get the generic type to be the own class? Seemed like such a simple thing at first... Edit: To explain it a little further with an example. Say you have an abstract class animals, then you extend it with Dogs and ants. I wouldn't want to compare ants with Dogs but I however would want to compare one dog with another. The dog might have a variable saying what color it is and that is what I want to use in the compareTo method. However when it comes to ants I would rather want to compare ant's size than their color. Hope that clears it up. Could possibly be a design flaw however.

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• Viewing namespaced global variables in Visual Studio debugger?

  - by Chris

  When debugging a non-managed C++ project in Visual Studio 2008, I occasionally want to see the value of a global variable. We don't have a lot of these but those that are there all declared within a namespace called 'global'. e.g. namespace global { int foo; bool bar; ... } The problem is that when the code is stopped at a breakpoint, the default debugging tooltip (from pointing at the variable name) and quickwatch (shift-f9 on the variable name) don't take the namespace into consideration and hence won't work. So for example I can point at 'foo' and nothing comes up. If I shift-f9 on foo, it will bring up the quickwatch, which then says 'CXX0017: Error: symbol "foo" not found'. I can get around that by manually editing the variable name in the quickwatch window to prefix it with "global::" (which is cumbersome considering you have to do it each time you want to quickwatch), but there is no fix for the tooltip that I can work out. Setting the 'default namespace' of the project properties doesn't help. How can I tell the VS debugger to use the namespace that it already knows the variable is declared in (since it has the declaration right there), or, alternatively, tell it a default namespace to look for variables in if it doesn't find them? My google-fu has failed to find an answer. This report lists the same problem, with MS saying it's "by design", but even so I am hoping there is some way to work around it (perhaps with clever use of autoexp.dat?)

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• Pros/cons of reading connection string from physical file vs Application object (ASP.NET)?

  - by HaterTot

  my ASP.NET application reads an xml file to determine which environment it's currently in (e.g. local, development, production). It checks this file every single time it opens a connection to the database, in order to know which connection string to grab from the Application Settings. I'm entering a phase of development where efficiency is becoming a concern. I don't think it's a good idea to have to read a file on a physical disk ever single time I wish to access the database (very often). I was considering storing the connection string in Application["ConnectionString"]. So the code would be public static string GetConnectionString { if (Application["ConnectionString"] == null) { XmlDocument doc = new XmlDocument(); doc.Load(HttpContext.Current.Request.PhysicalApplicationPath + "bin/ServerEnvironment.xml"); XmlElement xe = (XmlElement) xnl[0]; switch (xe.InnerText.ToString().ToLower()) { case "local": connString = Settings.Default.ConnectionStringLocal; break; case "development": connString = Settings.Default.ConnectionStringDevelopment; break; case "production": connString = Settings.Default.ConnectionStringProduction; break; default: throw new Exception("no connection string defined"); } Application["ConnectionString"] = connString; } return Application["ConnectionString"].ToString(); } I didn't design the application so I figure there must have been a reason for reading the xml file every time (to change settings while the application runs?) I have very little concept of the inner workings here. What are the pros and cons? Do you think I'd see a small performance gain by implementing the function above? THANKS

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• ConcurrentLinkedQueue$Node remains in heap after remove()

  - by action8

  I have a multithreaded app writing and reading a ConcurrentLinkedQueue, which is conceptually used to back entries in a list/table. I originally used a ConcurrentHashMap for this, which worked well. A new requirement required tracking the order entries came in, so they could be removed in oldest first order, depending on some conditions. ConcurrentLinkedQueue appeared to be a good choice, and functionally it works well. A configurable amount of entries are held in memory, and when a new entry is offered when the limit is reached, the queue is searched in oldest-first order for one that can be removed. Certain entries are not to be removed by the system and wait for client interaction. What appears to be happening is I have an entry at the front of the queue that occurred, say 100K entries ago. The queue appears to have the limited number of configured entries (size() == 100), but when profiling, I found that there were ~100K ConcurrentLinkedQueue$Node objects in memory. This appears to be by design, just glancing at the source for ConcurrentLinkedQueue, a remove merely removes the reference to the object being stored but leaves the linked list in place for iteration. Finally my question: Is there a "better" lazy way to handle a collection of this nature? I love the speed of the ConcurrentLinkedQueue, I just cant afford the unbounded leak that appears to be possible in this case. If not, it seems like I'd have to create a second structure to track order and may have the same issues, plus a synchronization concern.

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• Netbeans GUI building on pre-defined code

  - by deliriumtremens

  I am supposed edit some code for an assignment, and he gave us the framework and wants us to implement code for it. I load the project into netbeans and can't figure out how I'm supposed to edit the swing components. I don't see how to edit source vs. design. import javax.swing.*; import java.util.*; import java.io.*; public class CurrencyConverterGUI extends javax.swing.JFrame { /************************************************************************************************************** insert your code here - most of this will be generated by NetBeans, however, you must write code for the event listeners and handlers for the two ComboBoxes, the two TextBoxes, and the Button. Please note you must also poulate the ComboBoxes withe currency symbols (which are contained in the KeyList attribute of CurrencyConverter CC) ***************************************************************************************************************/ private CurrencyConverter CC; private javax.swing.JTextField Currency1Field; private javax.swing.JComboBox Currency1List; private javax.swing.JTextField Currency2Field; private javax.swing.JComboBox Currency2List; private javax.swing.JButton jButton1; private javax.swing.JPanel jPanel1; } class CurrencyConverter{ private HashMap HM; // contains the Currency symbols and conversion rates private ArrayList KeyList; // contains the list of currency symbols public CurrencyConverter() { /************************************************** Instantiate HM and KeyList and load data into them. Do this by reading the data from the Rates.txt file ***************************************************/ } public double convert(String FromCurrency, String ToCurrency, double amount){ /*************************************************************************** Will return the converted currency value. For example, to convert 100 USD to GBP, FromCurrency is USD, ToCurrency is GBP and amount is 100. The rate specified in the file represent the amount of each currency which is equivalent to one Euro (EUR). Therefore, 1 Euro is equivalent to 1.35 USD Use the rate specified for USD to convert to equivalent GBP: amount / USD_rate * GBP_rate ****************************************************************************/ } public ArrayList getKeys(){ // return KeyList } } This is what we were given, but I can't do anything with it inside the GUI editor. (Can't even get to the GUI editor). I have been staring at this for about an hour. Any ideas?

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• Advanced ASP.NET Gridview Layout

  - by chief7

  So i had a feature request to add fields to a second table row for a single data row on a GridView. At first, I looked at extending the functionality of the GridView but soon realized this would be a huge task and since I consider this request a shim for a larger future feature decided against it. Also want to move to MVC in the near future and this would be throw away code. So instead I created a little jquery script to move the cell to the next row in the table. $(document).ready(function() { $(".fieldAttributesNextRow").each(function() { var parent = $(this).parent(); var newRow = $("<tr></tr>"); newRow.attr("class", $(parent).attr("class")); var headerRow = $(parent).parent().find(":first"); var cellCount = headerRow.children().length - headerRow.children().find(".hide").length; newRow.append($(this).attr("colspan", cellCount)); $(parent).after(newRow); }) }); What do you think of this? Is this a poor design decision? I am actually quite pleased with the ease of this solution. Please provide your thoughts.

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• Can you overlay transparent images in Blackberry Apps?

  - by Greg

  I have a very simple application that has one screen and one button. The main screen has a verticalFieldManager with a BitmapField inside it, and one button beneath the bitmap. I want to be able to overlay another image on top of this when the user clicks a button. The overlay image is a PNG with transparent background, and this is important for design, so I can't use popupscreen or a new screen because the backgrounds are always white by default, and I've heard alpha doesn't really do the trick. I guess what I'm asking is if anyone knows a simple way to... A) take a standard verticalFieldManager and overlay a PNG on top of the inner contents B) overlay a PNG over the screen, no matter the contents The basic functionality of this app was intended to be - show an image. on click, show another overlaid on top. on click again, remove the popup image. I haven't found anything that addresses something like this online, but I have read of people doing similar things that utilize popupscreen and new screens in a way I don't need to do. Hopefully this makes sense. Thanks

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• Presenting an image cropping interface

  - by wkw

  I'm trying to engineer a UI for cropping images in iphone OS and suspect I'm going about things the hard way. My goal is pretty much what the Tapbots duo have done with Pastebot. In that app, they dim the source image but provide a movable and resizable cropping view and the image you're cropping is in a zoomable scrollview; when you resize or move the underlying image, the cropping view adjusts appropriately. I mocked up a composite image which will give a sense of the design I'm after, along with how I presently have my view hierarchy setup, viewable here The approach I've started with is the following: UIImageView with the image to crop is in a scrollview, a plain UIView with black fill and suitable transparency/alpha setting is added in front of the imageview. I then use a custom UIView which is a sibling to the scrollview at a higher level, which implements the drawRect: method and for the most part calls CGImageCreateWithImageInRect to get the portion of the image's bitmap that matches the position of the cropping view and draws that to the CGContext. in the viewcontroller I'm using the UIScrollViewDelegate methods to track scrolling and passing those changes to the custom cropping UIView so it stays in sync with the scroll contentOffset. That much is finally working. But trying to keep in sync as the scrollview zoomScale changes is when I figured I should ask for help. Looking for suggestions or guidance. My initial approach just seems like more work than is required. Could this be done with a masking layer in the ImageView? And if so, how would I setup the tracking for moving and resizing the cropping rect? My experience working with layers is non-nil, but very limited thus far.

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• Hibernate overriding database modifications with detached object state

  - by EugeneP

  I'm gonna go with this design: create an object and keep it alive during all web-app session. And I need to synchronize its state with database state. What I want to achieve is that : IF between my db operations, that is, modifications that I persist to a db someone intentionally spoils table rows, then on next saving to a database all those changes WOULD BE OVERWRITTEN with the object state, that always contains valid data. What Hibernate methods do you recommend me to use to persist the modifications in a database? saveOrUpdate() is a possible solution, but maybe there's anything better? Again, I repeat how it looks. First I create an object without collections. Persist it (save()). Then user provides us with additional data. In a serviceLayer, again, we modify our object in memory (say, populate it with collections) and then, persist it again. So every serviceLayer operation of the next step must simply guarantee that database contains the exact persistent copy of this object that we have in memory. If data in a database differ, it MUST BE OVERRIDDEN with the object (kept in memory) state. What Session operations do you recommend?

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