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  • C# - How to override GetHashCode with Lists in object

    - by Christian
    Hi, I am trying to create a "KeySet" to modify UIElement behaviour. The idea is to create a special function if, eg. the user clicks on an element while holding a. Or ctrl+a. My approach so far, first lets create a container for all possible modifiers. If I would simply allow a single key, it would be no problem. I could use a simple Dictionary, with Dictionary<Keys, Action> _specialActionList If the dictionary is empty, use the default action. If there are entries, check what action to use depending on current pressed keys And if I wasn't greedy, that would be it... Now of course, I want more. I want to allow multiple keys or modifiers. So I created a wrapper class, wich can be used as Key to my dictionary. There is an obvious problem when using a more complex class. Currently two different instances would create two different key, and thereby he would never find my function (see code to understand, really obvious) Now I checked this post: http://stackoverflow.com/questions/638761/c-gethashcode-override-of-object-containing-generic-array which helped a little. But my question is, is my basic design for the class ok. Should I use a hashset to store the modifier and normal keyboardkeys (instead of Lists). And If so, how would the GetHashCode function look like? I know, its a lot of code to write (boring hash functions), some tips would be sufficient to get me started. Will post tryouts here... And here comes the code so far, the Test obviously fails... public class KeyModifierSet { private readonly List<Key> _keys = new List<Key>(); private readonly List<ModifierKeys> _modifierKeys = new List<ModifierKeys>(); private static readonly Dictionary<KeyModifierSet, Action> _testDict = new Dictionary<KeyModifierSet, Action>(); public static void Test() { _testDict.Add(new KeyModifierSet(Key.A), () => Debug.WriteLine("nothing")); if (!_testDict.ContainsKey(new KeyModifierSet(Key.A))) throw new Exception("Not done yet, help :-)"); } public KeyModifierSet(IEnumerable<Key> keys, IEnumerable<ModifierKeys> modifierKeys) { foreach (var key in keys) _keys.Add(key); foreach (var key in modifierKeys) _modifierKeys.Add(key); } public KeyModifierSet(Key key, ModifierKeys modifierKey) { _keys.Add(key); _modifierKeys.Add(modifierKey); } public KeyModifierSet(Key key) { _keys.Add(key); } }

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  • mysql index optimization for a table with multiple indexes that index some of the same columns

    - by Sean
    I have a table that stores some basic data about visitor sessions on third party web sites. This is its structure: id, site_id, unixtime, unixtime_last, ip_address, uid There are four indexes: id, site_id/unixtime, site_id/ip_address, and site_id/uid There are many different types of ways that we query this table, and all of them are specific to the site_id. The index with unixtime is used to display the list of visitors for a given date or time range. The other two are used to find all visits from an IP address or a "uid" (a unique cookie value created for each visitor), as well as determining if this is a new visitor or a returning visitor. Obviously storing site_id inside 3 indexes is inefficient for both write speed and storage, but I see no way around it, since I need to be able to quickly query this data for a given specific site_id. Any ideas on making this more efficient? I don't really understand B-trees besides some very basic stuff, but it's more efficient to have the left-most column of an index be the one with the least variance - correct? Because I considered having the site_id being the second column of the index for both ip_address and uid but I think that would make the index less efficient since the IP and UID are going to vary more than the site ID will, because we only have about 8000 unique sites per database server, but millions of unique visitors across all ~8000 sites on a daily basis. I've also considered removing site_id from the IP and UID indexes completely, since the chances of the same visitor going to multiple sites that share the same database server are quite small, but in cases where this does happen, I fear it could be quite slow to determine if this is a new visitor to this site_id or not. The query would be something like: select id from sessions where uid = 'value' and site_id = 123 limit 1 ... so if this visitor had visited this site before, it would only need to find one row with this site_id before it stopped. This wouldn't be super fast necessarily, but acceptably fast. But say we have a site that gets 500,000 visitors a day, and a particular visitor loves this site and goes there 10 times a day. Now they happen to hit another site on the same database server for the first time. The above query could take quite a long time to search through all of the potentially thousands of rows for this UID, scattered all over the disk, since it wouldn't be finding one for this site ID. Any insight on making this as efficient as possible would be appreciated :) Update - this is a MyISAM table with MySQL 5.0. My concerns are both with performance as well as storage space. This table is both read and write heavy. If I had to choose between performance and storage, my biggest concern is performance - but both are important. We use memcached heavily in all areas of our service, but that's not an excuse to not care about the database design. I want the database to be as efficient as possible.

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  • Putting update logic in your migrations

    - by Daniel Abrahamsson
    A couple of times I've been in the situation where I've wanted to refactor the design of some model and have ended up putting update logic in migrations. However, as far as I've understood, this is not good practice (especially since you are encouraged to use your schema file for deployment, and not your migrations). How do you deal with these kind of problems? To clearify what I mean, say I have a User model. Since I thought there would only be two kinds of users, namely a "normal" user and an administrator, I chose to use a simple boolean field telling whether the user was an adminstrator or not. However, after I while I figured I needed some third kind of user, perhaps a moderator or something similar. In this case I add a UserType model (and the corresponding migration), and a second migration for removing the "admin" flag from the user table. And here comes the problem. In the "add_user_type_to_users" migration I have to map the admin flag value to a user type. Additionally, in order to do this, the user types have to exist, meaning I can not use the seeds file, but rather create the user types in the migration (also considered bad practice). Here comes some fictional code representing the situation: class CreateUserTypes < ActiveRecord::Migration def self.up create_table :user_types do |t| t.string :name, :nil => false, :unique => true end #Create basic types (can not put in seed, because of future migration dependency) UserType.create!(:name => "BASIC") UserType.create!(:name => "MODERATOR") UserType.create!(:name => "ADMINISTRATOR") end def self.down drop_table :user_types end end class AddTypeIdToUsers < ActiveRecord::Migration def self.up add_column :users, :type_id, :integer #Determine type via the admin flag basic = UserType.find_by_name("BASIC") admin = UserType.find_by_name("ADMINISTRATOR") User.all.each {|u| u.update_attribute(:type_id, (u.admin?) ? admin.id : basic.id)} #Remove the admin flag remove_column :users, :admin #Add foreign key execute "alter table users add constraint fk_user_type_id foreign key (type_id) references user_types (id)" end def self.down #Re-add the admin flag add_column :users, :admin, :boolean, :default => false #Reset the admin flag (this is the problematic update code) admin = UserType.find_by_name("ADMINISTRATOR") execute "update users set admin=true where type_id=#{admin.id}" #Remove foreign key constraint execute "alter table users drop foreign key fk_user_type_id" #Drop the type_id column remove_column :users, :type_id end end As you can see there are two problematic parts. First the row creation part in the first model, which is necessary if I would like to run all migrations in a row, then the "update" part in the second migration that maps the "admin" column to the "type_id" column. Any advice?

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  • Hidden Features of PHP?

    - by George Mauer
    EDIT: This didn't really start as a hidden features of PHP topic, but thats what it ended up as, so go nuts. I know this sounds like a point-whoring question but let me explain where I'm coming from. Out of college I got a job at a PHP shop. I worked there for a year and a half and thought that I had learned all there was to learn about programming. Then I got a job as a one-man internal development shop at a sizable corporation where all the work was in C#. In my commitment to the position I started reading a ton of blogs and books and quickly realized how wrong I was to think I knew everything. I learned about unit testing, dependency injection and decorator patterns, the design principle of loose coupling, the composition over inheritance debate, and so on and on and on - I am still very much absorbing it all. Needless to say my programming style has changed entirely in the last year. Now I find myself picking up a php project doing some coding for a friend's start-up and I feel completely constrained as opposed to programming in C#. It really bothers me that all variables at a class scope have to be referred to by appending '$this-' . It annoys me that none of the IDEs that I've tried have very good intellisense and that my SimpleTest unit tests methods have to start with the word 'test'. It drives me crazy that dynamic typing keeps me from specifying implicitly which parameter type a method expects, and that you have to write a switch statement to do method overloads. I can't stand that you can't have nested namespaces and have to use the :: operator to call the base class's constructor. Now I have no intention of starting a PHP vs C# debate, rather what I mean to say is that I'm sure there are some PHP features that I either don't know about or know about yet fail to use properly. I am set in my C# universe and having trouble seeing outside the glass bowl. So I'm asking, what are your favorite features of PHP? What are things you can do in it that you can't or are more difficult in the .Net languages?

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  • CDI SessionScoped Bean instance remains unchanged when login with different user

    - by Jason Yang
    I've been looking for the workaround of this problem for rather plenty of time and no result, so I ask question here. Simply speaking, I'm using a CDI SessionScoped Bean User in my project to manage user information and display them on jsf pages. Also container-managed j_security_check is used to resolve authentication issue. Everything is fine if first logout with session.invalidate() and then login in the same browser tab with a different user. But when I tried to directly login (through login.jsf) with a new user without logout beforehand, I found the user information remaining unchanged. I debugged and found the User bean, as well as the HttpSession instance, always remaining the same if login with different users in the same browser, as long as session.invalidate() not invoked. But oddly, the session id did modified, and I've both checked in Java code and Firebug. org.apache.catalina.session.StandardSessionFacade@5d7b4092 StandardSession[c69a71d19f369d08b5dddbea2ef0] attrName = org.jboss.weld.context.conversation.ConversationIdGenerator : attrValue=org.jboss.weld.context.conversation.ConversationIdGenerator@583c9dd8 attrName = org.jboss.weld.context.ConversationContext.conversations : attrValue = {} attrName = org.jboss.weld.context.http.HttpSessionContext#org.jboss.weld.bean-Discipline-ManagedBean-class com.netease.qa.discipline.profile.User : attrValue = Bean: Managed Bean [class com.netease.qa.discipline.profile.User] with qualifiers [@Any @Default @Named]; Instance: com.netease.qa.discipline.profile.User@c497c7c; CreationalContext: org.jboss.weld.context.CreationalContextImpl@739efd29 attrName = javax.faces.request.charset : attrValue = UTF-8 org.apache.catalina.session.StandardSessionFacade@5d7b4092 StandardSession[c6ab4b0c51ee0a649ef696faef75] attrName = org.jboss.weld.context.conversation.ConversationIdGenerator : attrValue = org.jboss.weld.context.conversation.ConversationIdGenerator@583c9dd8 attrName = com.sun.faces.renderkit.ServerSideStateHelper.LogicalViewMap : attrValue = {-4968076393130137442={-7694826198761889564=[Ljava.lang.Object;@43ff5d6c}} attrName = org.jboss.weld.context.ConversationContext.conversations : attrValue = {} attrName = org.jboss.weld.context.http.HttpSessionContext#org.jboss.weld.bean-Discipline-ManagedBean-class com.netease.qa.discipline.profile.User : attrValue = Bean: Managed Bean [class com.netease.qa.discipline.profile.User] with qualifiers [@Any @Default @Named]; Instance: com.netease.qa.discipline.profile.User@c497c7c; CreationalContext: org.jboss.weld.context.CreationalContextImpl@739efd29 attrName = javax.faces.request.charset : attrValue = UTF-8 Above block contains two successive logins and their Session info. We can see that the instance(1st row) the same while session id(2nd row) different. Seems that session object is reused to contain different session id and CDI framework manages session bean life cycle in accordance with the session object only(?). I'm wondering whether there could be only one server-side session object within the same browser unless invalidated? Since I'm adopting j_security_check I fancy intercepting it and invalidating old session is not so easy. So is it possible to accomplish the goal without altering the CDI+JSF+j_security_check design that one can relogin with different account in the same or different tab within the same browser? Really look forward for your response. More info: Glassfish v3.1 is my appserver.

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  • How to write a cctor and op= for a factory class with ptr to abstract member field?

    - by Kache4
    I'm extracting files from zip and rar archives into raw buffers. I created the following to wrap minizip and unrarlib: Archive.hpp #include "ArchiveBase.hpp" #include "ArchiveDerived.hpp" class Archive { public: Archive(string path) { /* logic here to determine type */ switch(type) { case RAR: archive_ = new ArchiveRar(path); break; case ZIP: archive_ = new ArchiveZip(path); break; case UNKNOWN_ARCHIVE: throw; break; } } Archive(Archive& other) { archive_ = // how do I copy an abstract class? } ~Archive() { delete archive_; } void passThrough(ArchiveBase::Data& data) { archive_->passThrough(data); } Archive& operator = (Archive& other) { if (this == &other) return *this; ArchiveBase* newArchive = // can't instantiate.... delete archive_; archive_ = newArchive; return *this; } private: ArchiveBase* archive_; } ArchiveBase.hpp class ArchiveBase { public: // Is there any way to put this struct in Archive instead, // so that outside classes instantiating one could use // Archive::Data instead of ArchiveBase::Data? struct Data { int field; }; virtual void passThrough(Data& data) = 0; /* more methods */ } ArchiveDerived.hpp "Derived" being "Zip" or "Rar" #include "ArchiveBase.hpp" class ArchiveDerived : public ArchiveBase { public: ArchiveDerived(string path); void passThrough(ArchiveBase::Data& data); private: /* fields needed by minizip/unrarlib */ // example zip: unzFile zipFile_; // example rar: RARHANDLE rarFile_; } ArchiveDerived.cpp #include "ArchiveDerived.hpp" ArchiveDerived::ArchiveDerived(string path) { //implement } ArchiveDerived::passThrough(ArchiveBase::Data& data) { //implement } Somebody had suggested I use this design so that I could do: Archive archiveFile(pathToZipOrRar); archiveFile.passThrough(extractParams); // yay polymorphism! How do I write a cctor for Archive? What about op= for Archive? What can I do about "renaming" ArchiveBase::Data to Archive::Data? (Both minizip and unrarlib use such structs for input and output. Data is generic for Zip & Rar and later is used to create the respective library's struct.)

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  • Learning to create beautiful /next-generation GUI

    - by ShaChris23
    I really want to create a stunning-looking GUI desktop application that looks like, for example: Mac OS X interface Picasa desktop client on windows IPhone apps Office 2007 I've mostly been programming GUI using Qt/Swing/WinForm and I'm tired of creating so plain looking GUI, lol. So I was thinking about diving into stuff like: jQuery WPF/C# iPhone SDK Silverlight Adobe Air/Flex Just to get some ideas on how to create really cool looking UI. Does that sound like a good list? Any developers here that could share what platform they use to create very cool looking desktop app? On a sidenote, I really wonder what developers at Apple / Microsoft use to develop their own cool-looking software. EDIT A lot of responses talk about the importance of usability over "cool-looking".. I totally agree that usability and simplicity are the most important aspects of user interface design. I've been doing GUI development for a while now ( 3 years), so that I understand. But using cool-looking UI also improves user experience + it could make big difference on whether or not your software sells. I mean, otherwise why would Microsoft/Apple try to make their OS UI look "cooler" everytime there's a new version? Why would websites like pragprog.com, or versionsapp.com. make their websites look like that? Basically you kill 2 birds with one stone: stunnning-looking UI + super usability (because it looks simple and intuitive). That is what I'm striving for. And as far as I know, I cannot achieve that using Qt/Winform. Most of the books I have read just show you how to make average-looking (read: 1990's) UI. I want to learn how to create cool-looking UI. And the only place I see cool-looking UIs these days are the technology I list above. I'm not enamored with any technology; but I just want to know how things are done in other technology to see if I could apply them to the technology I'm using, or see if I could use those technology in my line of work. An example: if I were to pick between this UI and this UI, I probably would pick the latter, if just based on looks alone. Functionally, they are just the same UI; they both allow you to keep track of your time. They both contain buttons and textboxes, etc. But the fact that they look different, also differentiate them in terms of attractiveness. So in all, I think the "ice on the cake" is very important. I would say it's the thing you strive for after you are certain you have a totally intuitive, usable UI.

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  • How to break a Hibernate session?

    - by Péter Török
    In the Hibernate reference, it is stated several times that All exceptions thrown by Hibernate are fatal. This means you have to roll back the database transaction and close the current Session. You aren’t allowed to continue working with a Session that threw an exception. One of our legacy apps uses a single session to update/insert many records from files into a DB table. Each recourd update/insert is done in a separate transaction, which is then duly committed (or rolled back in case an error occurred). Then for the next record a new transaction is opened etc. But the same session is used throughout the whole process, even if a HibernateException was caught in the middle. We are using Oracle 9i btw with Hibernate 3.24.sp1 on JBoss 4.2. Reading the above in the book, I realized that this design may fail. So I refactored the app to use a separate session for each record update. In a unit test with a mock session factory, I could prove that it is now requesting a new session for each record update. So far, so good. However, we found no way to reproduce the session failure while testing the whole app (would this be a stress test btw, or ...?). We thought of shutting down the listener of the DB but we realized that the app is keeping a bunch of connections open to the DB, and the listener would not affect those connections. (This is a web app, activated once every night by a scheduler, but it can also be activated via the browser.) Then we tried to kill some of those connections in the DB while the app was processing updates - this resulted in some failed updates, but then the app happily continued. Apparently Hibernate is clever enough to reopen broken connections under the hood without breaking the whole session. So this might not be a critical issue, as our app seems to be robust enough even in its original form. However, the issue keeps bugging me. I would like to know: Under what circumstances does the Hibernate session really become unusable after a HibernateException was thrown? How to reproduce this in a test? (What's the proper term for such a test?)

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  • Does this MSDN article violate MVVM?

    - by rasx
    This may be old news but back in March 2009, this article, “Model-View-ViewModel In Silverlight 2 Apps,” has a code sample that includes DataServiceEntityBase: // COPIED FROM SILVERLIGHTCONTRIB Project for simplicity /// <summary> /// Base class for DataService Data Contract classes to implement /// base functionality that is needed like INotifyPropertyChanged. /// Add the base class in the partial class to add the implementation. /// </summary> public abstract class DataServiceEntityBase : INotifyPropertyChanged { /// <summary> /// The handler for the registrants of the interface's event /// </summary> PropertyChangedEventHandler _propertyChangedHandler; /// <summary> /// Allow inheritors to fire the event more simply. /// </summary> /// <param name="propertyName"></param> protected void FirePropertyChanged(string propertyName) { if (_propertyChangedHandler != null) { _propertyChangedHandler(this, new PropertyChangedEventArgs(propertyName)); } } #region INotifyPropertyChanged Members /// <summary> /// The interface used to notify changes on the entity. /// </summary> event PropertyChangedEventHandler INotifyPropertyChanged.PropertyChanged { add { _propertyChangedHandler += value; } remove { _propertyChangedHandler -= value; } } #endregion What this class implies is that the developer intends to bind visuals directly to data (yes, a ViewModel is used but it defines an ObservableCollection of data objects). Is this design diverging too far from the guidance of MVVM? Now I can see some of the reasons Why would we go this way: what we can do with DataServiceEntityBase is this sort of thing (which is intimate with the Entity Framework): // Partial Method to support the INotifyPropertyChanged interface public partial class Game : DataServiceEntityBase { #region Partial Method INotifyPropertyChanged Implementation // Override the Changed partial methods to implement the // INotifyPropertyChanged interface // This helps with the Model implementation to be a mostly // DataBound implementation partial void OnDeveloperChanged() { base.FirePropertyChanged("Developer"); } partial void OnGenreChanged() { base.FirePropertyChanged("Genre"); } partial void OnListPriceChanged() { base.FirePropertyChanged("ListPrice"); } partial void OnListPriceCurrencyChanged() { base.FirePropertyChanged("ListPriceCurrency"); } partial void OnPlayerInfoChanged() { base.FirePropertyChanged("PlayerInfo"); } partial void OnProductDescriptionChanged() { base.FirePropertyChanged("ProductDescription"); } partial void OnProductIDChanged() { base.FirePropertyChanged("ProductID"); } partial void OnProductImageUrlChanged() { base.FirePropertyChanged("ProductImageUrl"); } partial void OnProductNameChanged() { base.FirePropertyChanged("ProductName"); } partial void OnProductTypeIDChanged() { base.FirePropertyChanged("ProductTypeID"); } partial void OnPublisherChanged() { base.FirePropertyChanged("Publisher"); } partial void OnRatingChanged() { base.FirePropertyChanged("Rating"); } partial void OnRatingUrlChanged() { base.FirePropertyChanged("RatingUrl"); } partial void OnReleaseDateChanged() { base.FirePropertyChanged("ReleaseDate"); } partial void OnSystemNameChanged() { base.FirePropertyChanged("SystemName"); } #endregion } Of course MSDN code can seen as “toy code” for educational purposes but is anyone doing anything like this in the real world of Silverlight development?

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  • Asynchronous vs Synchronous vs Threading in an iPhone App

    - by Coocoo4Cocoa
    I'm in the design stage for an app which will utilize a REST web service and sort of have a dilemma in as far as using asynchronous vs synchronous vs threading. Here's the scenario. Say you have three options to drill down into, each one having its own REST-based resource. I can either lazily load each one with a synchronous request, but that'll block the UI and prevent the user from hitting a back navigation button while data is retrieved. This case applies almost anywhere except for when your application requires a login screen. I can't see any reason to use synchronous HTTP requests vs asynchronous because of that reason alone. The only time it makes sense is to have a worker thread make your synchronous request, and notify the main thread when the request is done. This will prevent the block. The question then is bench marking your code and seeing which has more overhead, a threaded synchronous request or an asynchronous request. The problem with asynchronous requests is you need to either setup a smart notification or delegate system as you can have multiple requests for multiple resources happening at any given time. The other problem with them is if I have a class, say a singleton which is handling all of my data, I can't use asynchronous requests in a getter method. Meaning the following won't go: - (NSArray *)users { if(users == nil) users = do_async_request // NO GOOD return users; } whereas the following: - (NSArray *)users { if(users == nil) users == do_sync_request // OK. return users; } You also might have priority. What I mean by priority is if you look at Apple's Mail application on the iPhone, you'll notice they first suck down your entire POP/IMAP tree before making a second request to retrieve the first 2 lines (the default) of your message. I suppose my question to you experts is this. When are you using asynchronous, synchronous, threads -- and when are you using either async/sync in a thread? What kind of delegation system do you have setup to know what to do when a async request completes? Are you prioritizing your async requests? There's a gamut of solutions to this all too common problem. It's simple to hack something out. The problem is, I don't want to hack and I want to have something that's simple and easy to maintain.

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  • Using the HTML 'label' tag with radio buttons

    - by GlenPeterson
    Does the label tag work with radio buttons? If so, how do you use it? I have a form that displays like this: First Name: (text field) Hair Color: (color drop-down) Description: (text area) Salutation: (radio buttons for Mr., Mrs., Miss) I'd like to use the label tag for each label in the left column to define its connection to the appropriate control in the right column. But If I use a radio button, the spec seems to indicate that suddenly the actual "Salutation" label for the form control no longer belongs in the label tag, but rather the options "Mr., Mrs., etc." go in the label tag. I've always been a fan of accessibility and the semantic web, but this design doesn't make sense to me. The label tag explicitly declares labels. The option tag selection options. How do you declare a label on the actual label for a set of radio buttons? UPDATE: Here is an example with code: <tr><th><label for"sc">Status:</label></th> <td>&#160;</td> <td><select name="statusCode" id="sc"> <option value="ON_TIME">On Time</option> <option value="LATE">Late</option> </select></td></tr> This works great. But unlike other form controls, radio buttons have a separate field for each value: <tr><th align="right"><label for="???">Activity:</label></th> <td>&#160;</td> <td align="left"><input type="radio" name="es" value="" id="es0" /> Active &#160; <input type="radio" name="es" value="ON_TIME" checked="checked" id="es1" /> Completed on Time &#160; <input type="radio" name="es" value="LATE" id="es2" /> Completed Late &#160; <input type="radio" name="es" value="CANCELED" id="es3" /> Canceled</td> </tr> What to do?

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  • Is there a way to handle the dynamic change of a dropdown for a single row in a grid-based datawindo

    - by TomatoSandwich
    Is there a way to handle the dynamic change of a dropdown for a single row in a grid-based datawindow? Example: NAME LIKABILITY PURCHASED IN COLOUR (Text) (DropDown*) (Text) (Text) Bananas [Good] Hands Yellow [Bad] [Bananas are good] Apples [Good] Bags Red [Bad] Given the above is a grid-based datawindow, where the fields 'NAME','PURCHASED IN' and 'COLOUR' are text fields, where as the 'LIKABILITY' field is a dropdown*. I say dropdown* because the same visual representation can be created by using a DropDownList (hardcoded within the datawindow element at design time), or a DropDownDW (or DDDW, a select statement that can be based on other elements in the datawindow). However, there is no way I can get 'Bananas' having it's 3 dropdowns, while Apples has only 2. If I enter multiple rows of 'Bananas', then all rows have 3 dropdowns, but as soon as I add an Apples row, all dropdowns revert to 2 selections. To attempt to achieve this functionality, I have tried the following options: -- 1) dw_1.Object.likability.values("Good~tG/Bad~tB/Bananas are good~tDRWHO") on ue_itemchange when editing NAME. FAILS: edits all instances of LIKABILITY instead of the current row. -- 2) Duplicate Dropdowns, having one filtered, one unfiltered selection list per row, visible based on NAME selection. FAILS: can't set visibility/overlapping columns on grid-based datawindow. (Source) -- 3) Hard-code display value as Database value, or Vice Versa. Have 'GOOD','BAD','BANANASAREGOOD' as the display and database values, and change handling of options from G, B, DRWHO to these new values. FAILS: 3rd option appears for all rows, still selectable on Apple rows, which is wrong. -- 4) DDDW retrieve list of options for dropdown. Create a DDDW that uses the value of NAME to determine what selections it should have for the dropdown. FAILS: edits all instances of the dropdown, not just the current row. -- 5) DDDW retrieve counter of options available (if B then 3 else 2), then have duplicate dropdown columns that protect/unprotect based on DDDW counter. FAILS: Can't autoselect dddw value to populate column to cause protect on other two columns, ugly solution in any case. -- There is now a bounty on this question for anyone who can give me a solution that will enable me to edit a dropdown column for a single row on a grid-based datawindow in PB 10.5

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  • Adding a generic image field onto a ModelForm in django

    - by Prairiedogg
    I have two models, Room and Image. Image is a generic model that can tack onto any other model. I want to give users a form to upload an image when they post information about a room. I've written code that works, but I'm afraid I've done it the hard way, and specifically in a way that violates DRY. Was hoping someone who's a little more familiar with django forms could point out where I've gone wrong. Update: I've tried to clarify why I chose this design in comments to the current answers. To summarize: I didn't simply put an ImageField on the Room model because I wanted more than one image associated with the Room model. I chose a generic Image model because I wanted to add images to several different models. The alternatives I considered were were multiple foreign keys on a single Image class, which seemed messy, or multiple Image classes, which I thought would clutter my schema. I didn't make this clear in my first post, so sorry about that. Seeing as none of the answers so far has addressed how to make this a little more DRY I did come up with my own solution which was to add the upload path as a class attribute on the image model and reference that every time it's needed. # Models class Image(models.Model): content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') image = models.ImageField(_('Image'), height_field='', width_field='', upload_to='uploads/images', max_length=200) class Room(models.Model): name = models.CharField(max_length=50) image_set = generic.GenericRelation('Image') # The form class AddRoomForm(forms.ModelForm): image_1 = forms.ImageField() class Meta: model = Room # The view def handle_uploaded_file(f): # DRY violation, I've already specified the upload path in the image model upload_suffix = join('uploads/images', f.name) upload_path = join(settings.MEDIA_ROOT, upload_suffix) destination = open(upload_path, 'wb+') for chunk in f.chunks(): destination.write(chunk) destination.close() return upload_suffix def add_room(request, apartment_id, form_class=AddRoomForm, template='apartments/add_room.html'): apartment = Apartment.objects.get(id=apartment_id) if request.method == 'POST': form = form_class(request.POST, request.FILES) if form.is_valid(): room = form.save() image_1 = form.cleaned_data['image_1'] # Instead of writing a special function to handle the image, # shouldn't I just be able to pass it straight into Image.objects.create # ...but it doesn't seem to work for some reason, wrong syntax perhaps? upload_path = handle_uploaded_file(image_1) image = Image.objects.create(content_object=room, image=upload_path) return HttpResponseRedirect(room.get_absolute_url()) else: form = form_class() context = {'form': form, } return direct_to_template(request, template, extra_context=context)

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  • Unable to find valid certification path to requested target while CAS authentication

    - by Dmitriy Sukharev
    I'm trying to configure CAS authentication. It requires both CAS and client application to use HTTPS protocol. Unfortunately we should use self-signed certificate (with CN that doesn't have anything in common with our server). Also the server is behind firewall and we have only two ports (ssh and https) visible. As far as there're several application that should be visible externally, we use Apache for ajp reverse proxying requests to these applications. Secure connections are managed by Apache, and all Tomcat are not configured to work with SSL. But I obtained exception while authentication, therefore desided to set keystore in CATALINA_OPTS: export CATALINA_OPTS="-Djavax.net.ssl.keyStore=/path/to/tomcat/ssl/cert.pfx -Djavax.net.ssl.keyStoreType=PKCS12 -Djavax.net.ssl.keyStorePassword=password -Djavax.net.ssl.keyAlias=alias -Djavax.net.debug=ssl" cert.pfx was obtained from certificate and key that are used by Apache HTTP Server: $ openssl pkcs12 -export -out /path/to/tomcat/ssl/cert.pfx -inkey /path/to/apache2/ssl/server-key.pem -in /path/to/apache2/ssl/server-cert.pem When I try to authenticate a user I obtain the following exception: Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:174) ~[na:1.6.0_32] at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:238) ~[na:1.6.0_32] at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:318) ~[na:1.6.0_32] Meanwhile I can see in catalina.out that Tomcat see certificate in cert.pfx and it's the same as the one that is used while authentication: 09:11:38.886 [http-bio-8080-exec-2] DEBUG o.j.c.c.v.Cas20ProxyTicketValidator - Constructing validation url: https://external-ip/cas/proxyValidate?pgtUrl=https%3A%2F%2Fexternal-ip%2Fclient%2Fj_spring_cas_security_proxyreceptor&ticket=ST-17-PN26WtdsZqNmpUBS59RC-cas&service=https%3A%2F%2Fexternal-ip%2Fclient%2Fj_spring_cas_security_check 09:11:38.886 [http-bio-8080-exec-2] DEBUG o.j.c.c.v.Cas20ProxyTicketValidator - Retrieving response from server. keyStore is : /path/to/tomcat/ssl/cert.pfx keyStore type is : PKCS12 keyStore provider is : init keystore init keymanager of type SunX509 *** found key for : 1 chain [0] = [ [ Version: V1 Subject: CN=wrong.domain.name, O=Our organization, L=Location, ST=State, C=Country Signature Algorithm: SHA1withRSA, OID = 1.2.840.113549.1.1.5 Key: Sun RSA public key, 1024 bits modulus: 13??a lot of digits here??19 public exponent: ????7 Validity: [From: Tue Apr 24 16:32:18 CEST 2012, To: Wed Apr 24 16:32:18 CEST 2013] Issuer: CN=wrong.domain.name, O=Our organization, L=Location, ST=State, C=Country SerialNumber: [ d??????? ????????] ] Algorithm: [SHA1withRSA] Signature: 0000: 65 Signature is here 0070: 96 . ] *** trustStore is: /jdk-home-folder/jre/lib/security/cacerts Here is a lot of trusted CAs. Here is nothing related to our certicate or our (not trusted) CA. ... 09:11:39.731 [http-bio-8080-exec-4] DEBUG o.j.c.c.v.Cas20ProxyTicketValidator - Retrieving response from server. Allow unsafe renegotiation: false Allow legacy hello messages: true Is initial handshake: true Is secure renegotiation: false %% No cached client session *** ClientHello, TLSv1 RandomCookie: GMT: 1347433643 bytes = { 63, 239, 180, 32, 103, 140, 83, 7, 109, 149, 177, 80, 223, 79, 243, 244, 60, 191, 124, 139, 108, 5, 122, 238, 146, 1, 54, 218 } Session ID: {} Cipher Suites: [SSL_RSA_WITH_RC4_128_MD5, SSL_RSA_WITH_RC4_128_SHA, TLS_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_RSA_WITH_AES_128_CBC_SHA, TLS_DHE_DSS_WITH_AES_128_CBC_SHA, SSL_RSA_WITH_3DES_EDE_CBC_SHA, SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA, SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA, SSL_RSA_WITH_DES_CBC_SHA, SSL_DHE_RSA_WITH_DES_CBC_SHA, SSL_DHE_DSS_WITH_DES_CBC_SHA, SSL_RSA_EXPORT_WITH_RC4_40_MD5, SSL_RSA_EXPORT_WITH_DES40_CBC_SHA, SSL_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA, SSL_DHE_DSS_EXPORT_WITH_DES40_CBC_SHA, TLS_EMPTY_RENEGOTIATION_INFO_SCSV] Compression Methods: { 0 } *** http-bio-8080-exec-4, WRITE: TLSv1 Handshake, length = 75 http-bio-8080-exec-4, WRITE: SSLv2 client hello message, length = 101 http-bio-8080-exec-4, READ: TLSv1 Handshake, length = 81 *** ServerHello, TLSv1 RandomCookie: GMT: 1347433643 bytes = { 145, 237, 232, 63, 240, 104, 234, 201, 148, 235, 12, 222, 60, 75, 174, 0, 103, 38, 196, 181, 27, 226, 243, 61, 34, 7, 107, 72 } Session ID: {79, 202, 117, 79, 130, 216, 168, 38, 68, 29, 182, 82, 16, 25, 251, 66, 93, 108, 49, 133, 92, 108, 198, 23, 120, 120, 135, 151, 15, 13, 199, 87} Cipher Suite: SSL_RSA_WITH_RC4_128_SHA Compression Method: 0 Extension renegotiation_info, renegotiated_connection: <empty> *** %% Created: [Session-2, SSL_RSA_WITH_RC4_128_SHA] ** SSL_RSA_WITH_RC4_128_SHA http-bio-8080-exec-4, READ: TLSv1 Handshake, length = 609 *** Certificate chain chain [0] = [ [ Version: V1 Subject: CN=wrong.domain.name, O=Our organization, L=Location, ST=State, C=Country Signature Algorithm: SHA1withRSA, OID = 1.2.840.113549.1.1.5 Key: Sun RSA public key, 1024 bits modulus: 13??a lot of digits here??19 public exponent: ????7 Validity: [From: Tue Apr 24 16:32:18 CEST 2012, To: Wed Apr 24 16:32:18 CEST 2013] Issuer: CN=wrong.domain.name, O=Our organization, L=Location, ST=State, C=Country SerialNumber: [ d??????? ????????] ] Algorithm: [SHA1withRSA] Signature: 0000: 65 Signature is here 0070: 96 . ] *** http-bio-8080-exec-4, SEND TLSv1 ALERT: fatal, description = certificate_unknown http-bio-8080-exec-4, WRITE: TLSv1 Alert, length = 2 http-bio-8080-exec-4, called closeSocket() http-bio-8080-exec-4, handling exception: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target I tried to convert our pem certificate to der format and imported it to trustedKeyStore (cacerts) (without private key), but it didn't change anything. But I'm not confident that I did it rigth. Also I must inform you that I don't know passphrase for our servier-key.pem file, and probably it differs from password for keystore created by me. OS: CentOS 6.2 Architecture: x64 Tomcat version: 7 Apache HTTP Server version: 2.4 Is there any way to make Tomcat accepts our certificate?

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  • Spring/RMI server error

    - by 4herpsand7derpsago
    We have a Spring MVC web app (WAR) deploying to Tomcat (6.0.35) that launches a thread inside a separate JVM at deploy time (don't ask why - not my design) and then communicates with that thread via RMI over port 8888. Despite being totally convoluded, this was working perfectly fine up until yesterday, and now the thread is failing at startup and despite our best efforts to add logging into the mix, we are hitting a wall. This is the only exception we are able to find in the logs: Jun 12, 2012 3:11:36 AM com.ourapp.ImageController destroy SEVERE: Shutdown Error: Lookup of RMI stub failed; nested exception is java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: java.net.ConnectException: Connection refused Jun 12, 2012 3:11:37 AM org.apache.catalina.core.StandardContext listenerStop SEVERE: Exception sending context destroyed event to listener instance of class org.springframework.web.context.ContextLoaderListener java.lang.NoClassDefFoundError: org/springframework/web/context/ContextCleanupListener at org.springframework.web.context.ContextLoaderListener.contextDestroyed(ContextLoaderListener.java:80) at org.apache.catalina.core.StandardContext.listenerStop(StandardContext.java:3973) at org.apache.catalina.core.StandardContext.stop(StandardContext.java:4577) at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1165) at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1271) at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:296) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119) at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1337) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610) at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590) at java.lang.Thread.run(Thread.java:662) Caused by: java.lang.ClassNotFoundException: org.springframework.web.context.ContextCleanupListener at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1387) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1233) ... 12 more The ImageController is the Spring MVC Controller that is responsible for kicking off this daemon/spawned RMI thread. Based on the verbage of this error, does anybody have any idea what might be causing this "connection refused" error? Running a netstat -an | grep 8888 (this is a Linux machine) produces no output which means nothing is listening on that port. Thanks in advance for any ideas/suggestions that lead to a fix. Edit: Here's another ConnectionException we're seeing: Caused by: java.net.ConnectException: Connection refused at java.net.PlainSocketImpl.socketConnect(Native Method) at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351) at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213) at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200) at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) at java.net.Socket.connect(Socket.java:529) at java.net.Socket.connect(Socket.java:478) at java.net.Socket.<init>(Socket.java:375) at java.net.Socket.<init>(Socket.java:189) at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:22) at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:128) at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:595) ... 74 more

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  • Would someone mind giving suggestions for this new assembly language?

    - by Noctis Skytower
    Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo save Store load Retrieve L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller exit End the program print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

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  • android zxing intentintegrator

    - by cristi _b
    I've written the following code that works fine if you decide to scan a QR code (using zxing) and store it in private storage but in case you decide to cancel scanning, it crashes and the file previously stored content disappears. I think it might be a design error, not sure why. Below is relevant code ... /** * menu generation */ @Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.menu, menu); return true; } /** * menu handling */ @Override public boolean onOptionsItemSelected(MenuItem item) { Context context = getApplicationContext(); Toast toast = Toast.makeText(context, "", Toast.LENGTH_LONG); toast.setGravity(Gravity.FILL_HORIZONTAL, 0, 0); switch (item.getItemId()) { case R.id.qrScan: IntentIntegrator integrator = new IntentIntegrator(this); integrator.initiateScan(); return true; case R.id.qrReset: File dir = getFilesDir(); File file = new File(dir, qrCodeFile); boolean deleted = file.delete(); return true; case R.id.appClose: this.finish(); return true; default: return super.onOptionsItemSelected(item); } } ... public void onActivityResult(int requestCode, int resultCode, Intent intent) { IntentResult scanResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent); Context context = getApplicationContext(); Toast toast = Toast.makeText(context, "", Toast.LENGTH_SHORT); if (scanResult != null) { FileOutputStream fos = null; CharSequence text = scanResult.getContents(); try { fos = openFileOutput(qrCodeFile, Context.MODE_PRIVATE); try { fos.write(text.toString().getBytes()); fos.close(); toast.setGravity(Gravity.FILL_HORIZONTAL, 0, 0); toast.setText("Code saved"); toast.show(); } catch (IOException ex) { toast.setGravity(Gravity.FILL_HORIZONTAL, 0, 0); toast.setText("Invalid code"); toast.show(); Logger.getLogger(MainActivity.class.getName()).log(Level.SEVERE, null, ex); } } catch (FileNotFoundException ex) { toast.setGravity(Gravity.FILL_HORIZONTAL, 0, 0); toast.setText("Error while saving"); toast.show(); Logger.getLogger(MainActivity.class.getName()).log(Level.SEVERE, null, ex); } } else { toast.setGravity(Gravity.FILL_HORIZONTAL, 0, 0); toast.setText("Invalid code"); toast.show(); } }

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  • What Can I Do To One Of My Team Number (Good Friend As Well) Who Lost His Passion.

    - by skyflyer
    It seems this question is not program related, but there are lot of similar questions. So please bear with me! By the way, I am programmer and my team is also charging a software project. And SO is the only place which solved me lot of thorny troubles!THANK YOU GUYS! I joined my company with him years ago. At that time he was quite passionate on his job which is a front-end development. He gave us lot of useful suggestions concerning his work like design. And I believed he was a smart guy. I believe he still is smart too by the way. One years later, however, he seemed lost his passion and fooling around every day, did not care about his work any more and produced poorwork. Even worse he literally stopped learning new skills and honing his work related skills. For me it is horrible, we got to keep abreast with new technology development, otherwise we will be throw out. Since we were just coworkers, I did not care about it too much except mentioned my thoughts several times. But last month, we resembled a new group and assigned very important project. And I am the team leader, sadly! My boss gave me lot of support and expectation as well. I did a pretty good job before and I am very optimism to our future. But as a team, if my team does not work hard, we will be doomed to failure no matter how hard I work and push. In order to revitalize his passion, I tried couple of ways like talking to him about my concern and my boss's angry. I offered his new task which is quite new to him. I even persuaded my boss to give him new incentive package. But all of them knocked wall. His reaction was just he did not care. Even worse he did not want to talk about his situation. I want to be hard on him, but since we are friends and coworkers, I really can not see it will work. Even it works, I can not so quickly change my self from friend and coworker into manager. As a novice in management, I am really overwhelmed! I do not want get him fired, we are friends and I do not see him fired as my team number. What can I do? Thank you guys!

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  • Silverlight with MVVM Inheritance: ModelView and View matching the Model

    - by moonground.de
    Hello Stackoverflowers! :) Today I have a special question on Silverlight (4 RC) MVVM and inheritance concepts and looking for a best practice solution... I think that i understand the basic idea and concepts behind MVVM. My Model doesn't know anything about the ViewModel as the ViewModel itself doesn't know about the View. The ViewModel knows the Model and the Views know the ViewModels. Imagine the following basic (example) scenario (I'm trying to keep anything short and simple): My Model contains a ProductBase class with a few basic properties, a SimpleProduct : ProductBase adding a few more Properties and ExtendedProduct : ProductBase adding another properties. According to this Model I have several ViewModels, most essential SimpleProductViewModel : ViewModelBase and ExtendedProductViewModel : ViewModelBase. Last but not least, according Views SimpleProductView and ExtendedProductView. In future, I might add many product types (and matching Views + VMs). 1. How do i know which ViewModel to create when receiving a Model collection? After calling my data provider method, it will finally end up having a List<ProductBase>. It containts, for example, one SimpleProduct and two ExtendedProducts. How can I transform the results to an ObservableCollection<ViewModelBase> having the proper ViewModel types (one SimpleProductViewModel and two ExtendedProductViewModels) in it? I might check for Model type and construct the ViewModel accordingly, i.e. foreach(ProductBase currentProductBase in resultList) if (currentProductBase is SimpleProduct) viewModels.Add( new SimpleProductViewModel((SimpleProduct)currentProductBase)); else if (currentProductBase is ExtendedProduct) viewModels.Add( new ExtendedProductViewModels((ExtendedProduct)currentProductBase)); ... } ...but I consider this very bad practice as this code doesn't follow the object oriented design. The other way round, providing abstract Factory methods would reduce the code to: foreach(ProductBase currentProductBase in resultList) viewModels.Add(currentProductBase.CreateViewModel()) and would be perfectly extensible but since the Model doesn't know the ViewModels, that's not possible. I might bring interfaces into game here, but I haven't seen such approach proven yet. 2. How do i know which View to display when selecting a ViewModel? This is pretty the same problem, but on a higher level. Ended up finally having the desired ObservableCollection<ViewModelBase> collection would require the main view to choose a matching View for the ViewModel. In WPF, there is a DataTemplate concept which can supply a View upon a defined DataType. Unfortunately, this doesn't work in Silverlight and the only replacement I've found was the ResourceSelector of the SLExtensions toolkit which is buggy and not satisfying. Beside that, all problems from Question 1 apply as well. Do you have some hints or even a solution for the problems I describe, which you hopefully can understand from my explanation? Thank you in advance! Thomas

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  • decorator pattern

    - by vbNewbie
    I have a program that converts currency using a specific design pattern. I now need to take my converted result and using the decorator pattern allow the result to be converted to 3 different formats: 1 - exponential notation, rounded to 2 decimal points. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; namespace Converter { public partial class Form1 : Form { // Setup Chain of Responsibility Handler h1 = new USDHandler(); Handler h2 = new CADHandler(); Handler h3 = new AUDHandler(); public string reqCurName; public int reqAmt; public string results; public string requestID; public Form1() { InitializeComponent(); h1.SetSuccessor(h2); h2.SetSuccessor(h3); } // "Handler" private void button1_Click_1(object sender, EventArgs e) { reqCurName = txtInput.Text; reqAmt = Convert.ToInt32(txtAmt.Text.ToString()); results = h1.HandleRequest(reqCurName, reqAmt); if (results != "") { lblResult.Text = results; lblResult.Visible = true; } } abstract class Handler { protected Handler successor; public string retrn; public void SetSuccessor(Handler successor) { this.successor = successor; } public abstract string HandleRequest(string requestID, int reqAmt); } // "USD Handler" class USDHandler : Handler { public override string HandleRequest(string requestID, int reqAmt) { if (requestID == "USD") { retrn = "Request handled by " + this.GetType().Name + " \nConversion from Euro to USD is " + reqAmt/0.630479; return (retrn); } else if (successor != null) { retrn = successor.HandleRequest(requestID, reqAmt); } return (retrn); } } // "CAD Handler" class CADHandler : Handler { public override string HandleRequest(string requestID, int reqAmt) { if (requestID == "CAD") { retrn = "Request handled by " + this.GetType().Name + " \nConversion from Euro to CAD is " + reqAmt /0.617971; return (retrn); } else if (successor != null) { retrn = successor.HandleRequest(requestID, reqAmt); } return (retrn); } } // "AUD Handler" class AUDHandler : Handler { public override string HandleRequest(string requestID, int reqAmt) { if (requestID == "AUD") { requestID = "Request handled by " + this.GetType().Name + " \nConversion from Euro to AUD is " + reqAmt / 0.585386; return (requestID); } else if (successor != null) { retrn = successor.HandleRequest(requestID, reqAmt); } return (requestID); } } } }

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  • Why does the rename() syscall prohibit moving a directory that I can't write to a different director

    - by Daniel Papasian
    I am trying to understand why this design decision was made with the rename() syscall in 4.2BSD. There's nothing I'm trying to solve here, just understand the rationale for the behavior itself. 4.2BSD saw the introduction of the rename() syscall for the purpose of allowing atomic renames/moves of files. From 4.3BSD-Reno/src/sys/ufs/ufs_vnops.c: /* * If ".." must be changed (ie the directory gets a new * parent) then the source directory must not be in the * directory heirarchy above the target, as this would * orphan everything below the source directory. Also * the user must have write permission in the source so * as to be able to change "..". We must repeat the call * to namei, as the parent directory is unlocked by the * call to checkpath(). */ if (oldparent != dp->i_number) newparent = dp->i_number; if (doingdirectory && newparent) { VOP_LOCK(fndp->ni_vp); error = ufs_access(fndp->ni_vp, VWRITE, tndp->ni_cred); VOP_UNLOCK(fndp->ni_vp); So clearly this check was added intentionally. My question is - why? Is this behavior supposed to be intuitive? The effect of this is that one cannot move a directory (located in a directory that one can write) that one cannot write to another directory that one can write to atomically. You can, however, create a new directory, move the links over (assuming one has read access to the directory), and then remove one's write bit on the directory. You just can't do so atomically. % cd /tmp % mkdir stackoverflow-question % cd stackoverflow-question % mkdir directory-1 % mkdir directory-2 % mkdir directory-1/directory-i-cant-write % echo "foo" > directory-1/directory-i-cant-write/contents % chmod 000 directory-1/directory-i-cant-write/contents % chmod 000 directory-1/directory-i-cant-write % mv directory-1/directory-i-cant-write directory-2 mv: rename directory-1/directory-i-cant-write to directory-2/directory-i-cant-write: Permission denied We now have a directory I can't write with contents I can't read that I can't move atomically. I can, however, achieve the same effect non-atomically by changing permissions, making the new directory, using ln to create the new links, and changing permissions. (Left as an exercise to the reader) . and .. are special cased already, so I don't particularly buy that it is intuitive that if I can't write a directory I can't "change .." which is what the source suggests. Is there any reason for this besides it being the perceived correct behavior by the author of the code? Is there anything bad that can happen if we let people atomically move directories (that they can't write) between directories that they can write?

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  • How do I set up ServletForwardingController to intercept for jsp requests on weblogic

    - by dok
    My end goal is to be able to use the spring message tag with configured messageSource on a legacy app using a model-1 architecture. I've done this in tomcat with something like <bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource"> <property name="basename" value="WEB-INF/classes/bundle"/> </bean> <bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> <property name="mappings"> <props> <prop key="*">myServletForwardingController</prop> </props> </property> </bean> <bean id="myServletForwardingController" name="/**/*.jsp" class="org.springframework.web.servlet.mvc.ServletForwardingController"> <property name="servletName" value="jsp"/> </bean> For weblogic I have <bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource"> <property name="basenames"> <list> <value>WEB-INF/i18n/bundle</value> </list> </property> </bean> <bean name="/**/*.jsp" class="org.springframework.web.servlet.mvc.ServletForwardingController"> <property name="servletName" value="JspServlet"/> </bean> But, no luck. I'm getting a StackOverflowError when I attempt to access a JSP. java.lang.StackOverflowError at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:620) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124) at weblogic.utils.classloaders.GenericClassLoader.defineClass(GenericClassLoader.java:338) at weblogic.utils.classloaders.GenericClassLoader.findLocalClass(GenericClassLoader.java:291) at weblogic.utils.classloaders.GenericClassLoader.findClass(GenericClassLoader.java:259) at weblogic.utils.classloaders.ChangeAwareClassLoader.findClass(ChangeAwareClassLoader.java:54) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at java.lang.ClassLoader.loadClass(ClassLoader.java:251) at weblogic.utils.classloaders.GenericClassLoader.loadClass(GenericClassLoader.java:179) at weblogic.utils.classloaders.ChangeAwareClassLoader.loadClass(ChangeAwareClassLoader.java:35) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319) at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:620) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124) at weblogic.utils.classloaders.GenericClassLoader.defineClass(GenericClassLoader.java:338) at weblogic.utils.classloaders.GenericClassLoader.findLocalClass(GenericClassLoader.java:291) at weblogic.utils.classloaders.GenericClassLoader.findClass(GenericClassLoader.java:259) at weblogic.utils.classloaders.ChangeAwareClassLoader.findClass(ChangeAwareClassLoader.java:54) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at java.lang.ClassLoader.loadClass(ClassLoader.java:251) at weblogic.utils.classloaders.GenericClassLoader.loadClass(GenericClassLoader.java:179) at weblogic.utils.classloaders.ChangeAwareClassLoader.loadClass(ChangeAwareClassLoader.java:35) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:683) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:552) at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) at javax.servlet.http.HttpServlet.service(HttpServlet.java:820) at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:226) at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:124) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:283) at weblogic.servlet.internal.ServletStubImpl.onAddToMapException(ServletStubImpl.java:394) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:309) at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:175) at weblogic.servlet.internal.RequestDispatcherImpl.invokeServlet(RequestDispatcherImpl.java:533) at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:266) at org.springframework.web.servlet.mvc.ServletForwardingController.handleRequestInternal(ServletForwardingController.java:129) at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:153) at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:48) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:771) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:716) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:647) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:552) at javax.servlet.http.HttpServlet.service(HttpServlet.java:707) at javax.servlet.http.HttpServlet.service(HttpServlet.java:820) ...

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  • How do we, as a community, help encourage programming in public schools? (Or state Schools for the U

    - by NoMoreZealots
    PRIMARY MOTIVATION My office gets involved with the "First Robotics" competitions and one thing that lingers year to year is the students typically have no preparation for doing even simple programming as part of the public schools system. While the science classes provide some basic grasp of mechanical and electrical concepts, by in large computer programming gets no coverage from the curriculum. (This my be different in other areas of the country/world.) What makes it worse is there is only a short period of time you have to prepare the student's and help them design the robot. Talking to some professors from local colleges, it's a problem because you can't assume even the most basic understanding for freshman CS majors. Languages like Python, Lua and BASIC are simple enough for at least high school level students, if not younger. SCOPE So how do you get public schools to support a programming, at least to the level of "Try it in BASIC" examples that used to be at the end of a chapter in my Algebra book? At least enough to prepare them for event's such as the FIRST Robotic competitions. Which the primary objectives are to teach problem solving and team work, and to possible foster an interest in Math, Science and Engineering in general. (Not force feed to them, as some people her seem to be implying.) Edit: Why teach kids: (Since 2000 CS enrollment in US colleges has decreased by 70% while college enrollment has increased, this is a PROBLEM.) Saying there is no value in teaching someone programming in Jr./High school because they might think "they know programming." Is like saying there's no value in teaching High school science and physics, because they might decide they "know physics." Leading to abuse like: "I passed a high school physics class, I'm going to develop a Unified Quantum Gravitational Theory." Better Prepared students are better students. Instead it would allows college programs to raise the bar on the entry level courses, allowing students to be weeded out based on their understanding of more advanced material. Plus people who did poorly in that in topic in High school aren't as likely to say "I think there's money in computer's so I'll computer science." Plus if people take it in high school and decide THEN that it's not for them, it's better than them wasting their money to PAY a college to figure that out. The result is that people who take the degree are more likely to succeed and be there for the RIGHT reasons. (i.e. It's what they REALLY want to do. And that's REALLY the key to being good at anything.) Programming is like anything else, the more practice and genuine interest you have the better you get. If you start them later, they get less practice. The earlier give them the opportunity to start, the more practice they will get. All other things equal, the more practice the better the programmer.

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  • Database Logon Error in crystal report

    - by yasar arafat
    am really very dumb as this problem is being answered so many times but eally its above my head. i dont have any idea about working with crystal reports or asp.net but due to some reason i have to work on it. after trying very hard i m able to design on crystal report connecting it with mysql database. now when i see in the crystalreport preview i am able to see the report and the data ![enter image description here][1] but when i try to run it on server it says database logon failed![enter image description here][2] now i really dont know what to do i am pasting my aspx and aspx.vb code here and please repley in english not computer language believe me i m super dumb enter code here aspx codes <%@ Page Title="" Language="VB" MasterPageFile="~/Master/Site.master"AutoEventWireup="false" CodeFile="ManHourCostExpenditure.aspx.vb" Inherits="ManHourCostExpenditure" %> <%@ Register assembly="CrystalDecisions.Web, Version=13.0.2000.0, Culture=neutral, PublicKeyToken=692fbea5521e1304" namespace="CrystalDecisions.Web" tagprefix="CR" %> <asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"> </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" Runat="Server"> <CR:CrystalReportViewer ID="CrystalReportViewer1" runat="server" AutoDataBind="True" EnableDatabaseLogonPrompt="False" EnableParameterPrompt="False" GroupTreeImagesFolderUrl="" Height="1202px" ReportSourceID="CrystalReportSource1" ToolbarImagesFolderUrl="" ToolPanelView="None" ToolPanelWidth="200px" Width="903px" BorderColor="#660033" BorderStyle="Solid" BorderWidth="1px" HasCrystalLogo="False" /> <CR:CrystalReportSource ID="CrystalReportSource1" runat="server"> <Report FileName="CrDiscProjManHoursActVsEst.rpt"> </Report> </CR:CrystalReportSource> </asp:Content> aspxdotvb codes Imports CrystalDecisions.CrystalReports.Engine Imports CrystalDecisions.Shared Imports CrystalDecisions.Enterprise Imports CrystalDecisions.ReportSource Imports CrystalDecisions.Web Imports CrystalDecisions.Windows.Forms Imports MySql Imports MySql.Data Imports MySql.Data.MySqlClient Imports System.Collections Imports System.Collections.Generic Imports System.Text Imports CrystalDecisions Imports CrystalDecisions.CrystalReports Imports CrystalReportsReportDefModelLib Partial Class ManHourCostExpenditure Inherits System.Web.UI.Page Dim CrRpt As New CrystalDecisions.CrystalReports.Engine.ReportDocument Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim StrConn As String = "SERVER=localhost;DATABASE=fluor;UID=root; PWD=root;" Dim Conn As New MySqlConnection(StrConn) Conn.Open() Dim CrRpt As New CrystalDecisions.CrystalReports.Engine.ReportDocument 'Session.Add("REPORT_KEY", CrRpt) CrRpt.Load(Server.MapPath("CrManHourCostExpenditure.rpt")) CrRpt.PrintOptions.PaperOrientation = PaperOrientation.Landscape 'If IsPostBack Then ' CrRpt = CType(Session.Item("REPORT_KEY"), Group) ' CrystalReportViewer1.ReportSource = CrRpt 'End If CrystalReportViewer1.ReportSource = CrRpt 'CrystalReportViewer1.DataBind() CrystalReportViewer1.RefreshReport() Conn.Close() 'CrRpt.Close() 'CrRpt.Dispose() End Sub Protected Sub Page_Unload(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Unload 'CrystalReportViewer1.ReportSource.Close() CrRpt.Close() CrRpt.Dispose() End Sub 'Protected Sub CrystalReportViewer1_Unload(ByVal sender As Object, ByVal e As System.EventArgs) Handles CrystalReportViewer1.Unload ' CrRpt.Close() ' CrRpt.Dispose() 'End Sub End Class please help me. thanks in advance.... yasir

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  • WPF binding behaviour different when bound property is declared as interface vs class type?

    - by Jay
    This started with weird behaviour that I thought was tied to my implementation of ToString(), and I asked this question: http://stackoverflow.com/questions/2916068/why-wont-wpf-databindings-show-text-when-tostring-has-a-collaborating-object It turns out to have nothing to do with collaborators and is reproducible. When I bind Label.Content to a property of the DataContext that is declared as an interface type, ToString() is called on the runtime object and the label displays the result. When I bind TextBlock.Text to the same property, ToString() is never called and nothing is displayed. But, if I change the declared property to a concrete implementation of the interface, it works as expected. Is this somehow by design? If so, any idea why? To reproduce: Create a new WPF Application (.NET 3.5 SP1) Add the following classes: public interface IFoo { string foo_part1 { get; set; } string foo_part2 { get; set; } } public class Foo : IFoo { public string foo_part1 { get; set; } public string foo_part2 { get; set; } public override string ToString() { return foo_part1 + " - " + foo_part2; } } public class Bar { public IFoo foo { get { return new Foo {foo_part1 = "first", foo_part2 = "second"}; } } } Set the XAML of Window1 to: <Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300"> <StackPanel> <Label Content="{Binding foo, Mode=Default}"/> <TextBlock Text="{Binding foo, Mode=Default}"/> </StackPanel> </Window> in Window1.xaml.cs: public partial class Window1 : Window { public Window1() { InitializeComponent(); DataContext = new Bar(); } } When you run this application, you'll see the text only once (at the top, in the label). If you change the type of foo property on Bar class to Foo (instead of IFoo) and run the application again, you'll see the text in both controls.

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