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  • Is this an example for parametric polymorphism?

    - by mrt181
    Hi i am educating myself oop principles. I would like to know if this is a correct example of Cardellis definition of parametric polymorphism. Please enlighten me. The example is in cfml's script based syntax. <cfcomponent> <cfscript> public numeric function getlength(any arg, string type){ switch (arguments.type){ case "array": return arraylen(arguments.arg); break; case "struct": return structcount(arguments.arg); break; case "string": return len(arguments.arg); break; case "numeric": return len(arguments.arg); break; case "object": // gets the number of parent classes, substracting the railo base class return -1 + arraylen(structfindkey(getmetadata(arguments.arg),"extends","all")); break; default: // throw was added to railo as a user defined function to use it in cfscript throw("InvalidTypeArgument","The provided type argument is invalid for method getlength"); } } </cfscript> </cfcomponent>

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  • ISO/IEC Website and Charging for C and C++ Standards

    - by Michael Aaron Safyan
    The ISO C Standard (ISO/IEC 9899) and the ISO C++ Standard (ISO/IEC 14882) are not published online; instead, one must purchase the PDF for each of those standards. I am wondering what the rationale is behind this... is it not detrimental to both the C and C++ programming languages that the authoritative specification for these languages is not made freely available and searchable online? Doesn't this encourage the use of possibly inaccurate, non-authoritative sources for information regarding these standards? While I understand that much time and effort has gone into developing the C and C++ standards, I am still somewhat puzzled by the choice to charge for the specification. The OpenGroup Base Specification, for example, is available for free online; they make money buy charging for certification. Does anyone know why the ISO standards committees don't make their revenue in certifying standards compliance, instead of charging for these documents? Also, does anyone know if the ISO standards committee's atrociously looking website is intentionally made to look that way? It's as if they don't want people visiting and buying the spec. One last thing... the C and C++ standards are generally described as "open standards"... while I realize that this means that anyone is permitted to implement the standard, should that definition of "open" be revised? Charging for the standard rather than making it openly available seems contrary to the spirit of openness. P.S. I do have a copy of the ISO/IEC 9899:1999 and ISO/IEC 14882:2003, so please no remarks about being cheap or anything... although if you are tempted to say such things, you might want to consider the high school, undergraduate, and graduate students who might not have all that much extra cash. Also, you might want to consider the fact that the ISO website is really sketchy and they don't even tell you the cost until you proceed to the checkout... doesn't really encourage one to go and get a copy, now does it?

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  • Volatile fields in C#

    - by Danny Chen
    From the specification 10.5.3 Volatile fields: The type of a volatile field must be one of the following: A reference-type. The type byte, sbyte, short, ushort, int, uint, char, float, bool, System.IntPtr, or System.UIntPtr. An enum-type having an enum base type of byte, sbyte, short, ushort, int, or uint. First I want to confirm my understanding is correct: I guess the above types can be volatile because they are stored as a 4-bytes unit in memory(for reference types because of its address), which guarantees the read/write operation is atomic. A double/long/etc type can't be volatile because they are not atomic reading/writing since they are more than 4 bytes in memory. Is my understanding correct? And the second, if the first guess is correct, why a user defined struct with only one int field in it(or something similar, 4 bytes is ok) can't be volatile? Theoretically it's atomic right? Or it's not allowed simply because that all user defined structs(which is possibly more than 4 bytes) are not allowed to volatile by design?

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  • equality on the sender of an event

    - by Berryl
    I have an interface for a UI widget, two of which are attributes of a presenter. public IMatrixWidget NonProjectActivityMatrix { set { // validate the incoming value and set the field _nonProjectActivityMatrix = value; .... // configure & load non-project activities } public IMatrixWidget ProjectActivityMatrix { set { // validate the incoming value and set the field _projectActivityMatrix = value; .... // configure & load project activities } The widget has an event that both presenter objects subscribe to, and so there is an event handler in the presenter like so: public void OnActivityEntry(object sender, EntryChangedEventArgs e) { // calculate newTotal here .... if (ReferenceEquals(sender, _nonProjectActivityMatrix)) { _nonProjectActivityMatrix.UpdateTotalHours(feedback.ActivityTotal); } else if (ReferenceEquals(sender, _projectActivityMatrix)) { _projectActivityMatrix.UpdateTotalHours(feedback.ActivityTotal); } else { // ERROR - we should never be here } } The problem is that the ReferenceEquals on the sender fails, even though it is the implemented widget that is the sender - the same implemented widget that was set to the presenter attribute! Can anyone spot what the problem / fix is? Cheers, Berryl I didn't know you could edit nicely. Cool. Here is the event raising code: void OnGridViewNumericUpDownEditingControl_ValueChanged(object sender, EventArgs e) { // omitted to save sapce if (EntryChanged == null) return; var args = new EntryChangedEventArgs(activityID, dayID, Convert.ToDouble(amount)); EntryChanged(this, args); } Here is the debugger dump of the presenter attribute, sans namespace info: ?_nonProjectActivityMatrix {WinPresentation.Widgets.MatrixWidgetDgv} [WinPresentation.Widgets.MatrixWidgetDgv]: {WinPresentation.Widgets.MatrixWidgetDgv} Here is the debugger dump of the sender: ?sender {WinPresentation.Widgets.MatrixWidgetDgv} base {Core.GUI.Widgets.Lookup.MatrixWidgetBase<Core.GUI.Widgets.Lookup.DynamicDisplayDto>}: {WinPresentation.Widgets.MatrixWidgetDgv} _configuration: {Domain.Presentation.Timesheet.Matrix.WeeklyMatrixConfiguration} _wrappedWidget: {Win.Widgets.DataGridViewDynamicLookupWidget} AllowUserToAddRows: true ColumnCount: 11 Count: 4 EntryChanged: {Method = {Void OnActivityEntry(System.Object, Smack.ConstructionAdmin.Domain.Presentation.Timesheet.Matrix.EntryChangedEventArgs)}} SelectedCell: {DataGridViewNumericUpDownCell { ColumnIndex=3, RowIndex=3 }} SelectedCellValue: "0.00" SelectedColumn: {DataGridViewNumericUpDownColumn { Name=MONDAY, Index=3 }} SelectedItem: {'AdministrativeActivity: 130-04', , AdministrativeTime, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00} Berryl

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  • Google Web Toolkit or Microsoft Technology (Silverlight, ASP.NET)

    - by NativeByte
    We have a large code base in MFC and VB. A few applications are in .NET. All these applications interoperate with each other on the user's machine and also connect with Unix servers via sockets. Recently we have started discussing a re-write of our applications and possibility of moving a lot of these desktop applications to web (they would run in intranet). A straight forward way is rewritting them in one of the .NET technologies. But a suggestion about using Google Web tookit has popped up and the argument is that it would help creating applications that would run in a browser on both desktop and mobile devices. One of the key problem that I see is that GWT is a large abstraction over Javascript. This will require the team to learn GWT, Javascript, IDEs etc as their experience has been primarily Microsoft technologies and not Java. It would be easier for them to learn .NET technologies instead of GWT. I do not have a depth of GWT and its drawback pittfalls and do not know about a parallel Microsoft Technology that I should investigate. So I would appreciate if people here can share their views or experiences using GWT or equivalent Microsoft technology.

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  • How to exit grid with ctrl-TAB when grid is on a tabpage (onkeydown works when grid not on tabpage)

    - by Charles Hankey
    winforms .net 3.5 Ultrawingrid 9.2 In my subclass of Ultrawingrid.Ultragrid : Protected Overrides Sub OnKeyDown(ByVal e As System.Windows.Forms.KeyEventArgs) If e.KeyCode = Windows.Forms.Keys.Tab andalso e.control = True then SetFocusToNextControl(True) End if Mybase.OnKeyDown(e) End Sub This works fine. But when the grid is dropped on a TabControl tabpage, the ctrl-tab looks very different to the sub above. e.keycode is seen as controlkey {17} I realize that by default cntrl-Tab moves between tabpages. I need to override this behavior. My thought is I probably need a subclass of the tabControl which will pass the keycombo through just as the form does but I confess to being clueless as to how to accomplish that. I tried to override the onkeydown of a tabcontrol subclass and just issuing a return and not and base call to onkeydown if the ctrl-tab combo was pressed but it seemed to see the e.keycode as controlkey as well. FWIW I tried a different combination like ctrl-E and got pretty much the same result with focus disappearing from the grid but not going anywhere I could detect. The sub still saw the e.control as controlkey. Oddly, ctrl-X, ctrl-A etc all work in the grid and a ctrl-Delete combo I put in the subclass for deleting a row works fine. Once again - grid directly on form and it all works. I'm definitely over my head on this one. Guidance much appreciated. vb or c# fine. TIA

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  • Paramaterising SQL in SSIS

    - by Anonymouslemming
    Hi all, I'm trying to paramaterize some queries in SSIS. After some reading, it sounds like my best option is to create one variable that contains my base sql, another that contains my criteria and a final variable that is evaluated as an expression that includes both of these. I want to end up with an SQL query that is effectively UPDATE mytable set something='bar' where something_else='foo' So my first two variables have the scope of my package and are as follows: Name: BaseSQL Data Type: String Value: UPDATE mytable set something = 'bar' where something_else = Name: MyVariable Data Type: String Value: foo My third variable has a scope of the data flow task where I want to use this SQL and is as follows: Name: SQLQuery Data Type: String Value: @[User::BaseSQL] + "'" + @[User::MyVariable] + "'" EvaluateAsExpression: True In the OLE DB Source, I then choose my connection and 'SQL command from variable' and select User::SQLQuery from the dropdown box. The Variable Value window then displays the following: @[User::BaseSQL] + "'" + @[User::MyVariable] + "'" This is as desired, and would provide the output I want from my DB. The variable name dropdown also contains User::BaseSQL and User::MyVariable so I believe that my namespaces are correct. However, when I then click preview, I get the following error when configuring an OLE DB Source (using SQL command from variable): TITLE: Microsoft Visual Studio Error at Set runtime in DB [Set runtime in myDb DB [1]]: SSIS Error Code DTS_E_OLEDBERROR. An OLE DB error has occurred. Error code: 0x80040E14. An OLE DB record is available. Source: "Microsoft SQL Server Native Client 10.0" Hresult: 0x80040E14 Description: "Statement(s) could not be prepared.". An OLE DB record is available. Source: "Microsoft SQL Server Native Client 10.0" Hresult: 0x80040E14 Description: "Must declare the scalar variable "@".". (Microsoft Visual Studio) Can anyone advise what I'm missing or how I can resolve this please ? Thanks in advance!

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  • firefox lead dot in cookie issue

    - by Jon
    Hi all, We are having an annoying issue with Firefox and cookies. We have the following domains: sub1.mydomain.com sub2.mydomain.com sub3.mydomain.com otherdomain.com We have converting our framework to be multilingual and providing a drop down to change the language at any point during site. The code base is shared across all the domains above. We can not set a cookie across all "mydomain.com" sites, they have to be on each of the sub domains. To get this to work we set a JavaScript cookie when the users chooses a new language. When the page posts back to the server the code picks this up and sets the users preferences to that new language code, (this is all C# and ASP.NET). We have to set the host to be "subX.mydomain.com" and the path to be "/" in the cookie so that it is just for the subdomain and all parts of that domain. This works great on all browsers apart from FireFox. It seems that firefox will pre append a DOT to the beginning of domain so ".subX.mydomain.com". When the code posts back with FireFox the cookie is always null. Has anyone had this situation, (I imagine it is not al that uncommon). I have read a lot of people saying, remove the domain from the cookie, but that can not work for us as we have multiple subdomains that need their own cookie values. Thanks

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  • MySQL Connector: parameters not being added

    - by LookitsPuck
    Hey all! Looking at my query log for MySQL, I see my parameters aren't being added. Here's my code: MySqlConnection conn = new MySqlConnection(ApplicationVariables.ConnectionString()); MySqlCommand com = new MySqlCommand(); try { conn.Open(); com.Connection = conn; com.CommandText = String.Format(@"SELECT COUNT(*) AS totalViews FROM pr_postreleaseviewslog AS prvl WHERE prvl.dateCreated BETWEEN (@startDate) AND (@endDate) AND prvl.postreleaseID IN ({0})" , ids); com.CommandType = CommandType.Text; com.Parameters.Add(new MySqlParameter("@startDate", thisCampaign.Startdate)); com.Parameters.Add(new MySqlParameter("@endDate", endDate)); numViews = Convert.ToInt32(com.ExecuteScalar()); } catch (Exception ex) { } finally { conn.Dispose(); com.Dispose(); } Looking at the query log, I see this: SELECT COUNT(*) AS totalViews FROM pr_postreleaseviewslog AS prvl WHERE prvl.dateCreated BETWEEN (@startDate) AND (@endDate) AND prvl.postreleaseID IN (1,2) I've used the MySQL .NET connector on countless projects (I actually have a base class that takes care of opening these connections, and closing them with transactions, etc.). However, I took over this application, and here I am now. Thanks for the help!

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  • How to use symbols/punctuation characters in discriminated unions

    - by user343550
    I'm trying to create a discriminated union for part of speech tags and other labels returned by a natural language parser. It's common to use either strings or enums for these in C#/Java, but discriminated unions seem more appropriate in F# because these are distinct, read-only values. In the language reference, I found that this symbol ``...`` can be used to delimit keywords/reserved words. This works for type ArgumentType = | A0 // subject | A1 // indirect object | A2 // direct object | A3 // | A4 // | A5 // | AA // | ``AM-ADV`` However, the tags contain symbols like $, e.g. type PosTag = | CC // Coordinating conjunction | CD // Cardinal Number | DT // Determiner | EX // Existential there | FW // Foreign Word | IN // Preposision or subordinating conjunction | JJ // Adjective | JJR // Adjective, comparative | JJS // Adjective, superlative | LS // List Item Marker | MD // Modal | NN // Noun, singular or mass | NNP // Proper Noun, singular | NNPS // Proper Noun, plural | NNS // Noun, plural | PDT // Predeterminer | POS // Possessive Ending | PRP // Personal Pronoun | PRP$ //$ Possessive Pronoun | RB // Adverb | RBR // Adverb, comparative | RBS // Adverb, superlative | RP // Particle | SYM // Symbol | TO // to | UH // Interjection | VB // Verb, base form | VBD // Verb, past tense | VBG // Verb, gerund or persent participle | VBN // Verb, past participle | VBP // Verb, non-3rd person singular present | VBZ // Verb, 3rd person singular present | WDT // Wh-determiner | WP // Wh-pronoun | WP$ //$ Possessive wh-pronoun | WRB // Wh-adverb | ``#`` | ``$`` | ``''`` | ``(`` | ``)`` | ``,`` | ``.`` | ``:`` | `` //not sure how to escape/delimit this ``...`` isn't working for WP$ or symbols like ( Also, I have the interesting problem that the parser returns `` as a meaningful symbol, so I need to escape it as well. Is there some other way to do this, or is this just not possible with a discriminated union? Right now I'm getting errors like Invalid namespace, module, type or union case name Discriminated union cases and exception labels must be uppercase identifiers I suppose I could somehow override toString for these goofy cases and replace the symbols with some alphanumeric equivalent?

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  • does sfWidgetFormSelect provide a string or an int of the selected item?

    - by han
    Hey guys, I'm having an annoying problem. I'm trying to find out what fields of a form were changed, and then insert that into a table. I managed to var_dump in doUpdateObjectas shown in the following public function doUpdateObject($values) { parent::doUpdateObject($values); var_dump($this->getObject()->getModified(false)); var_dump($this->getObject()->getModified(true)); } And it seems like $this-getObject()-getModified seems to work in giving me both before and after values by setting it to either true or false. The problem that I'm facing right now is that, some how, sfWidgetFormSelect seems to be saving one of my fields as a string. before saving, that exact same field was an int. (I got this idea by var_dump both before and after). Here is what the results on both var dumps showed: array(1) {["annoying_field"]=> int(3)} array(1) {["annoying_field"]=>string(1)"3"} This seems to cause doctrine to think that this is a modification and thus gives a false positive. In my base form, I have under $this->getWidgets() 'annoying_field' => new sfWidgetFormInputText(), under $this->setValidators 'annoying_field' => new sfValidatorInteger(array('required' => false)), and lastly in my configured Form.class.php I have reconfigured the file as such: $this->widgetSchema['annoying_field'] = new sfWidgetFormSelect(array('choices' => $statuses)); statuses is an array containing values like {""a", "b", "c", "d"} and I just want the index of the status to be stored in the database. And also how can I insert the changes into another database table? let's say my Log table? Any ideas and advice as to why this is happen is appreciated, I've been trying to figure it out and browsing google for various keywords with no avail. Thanks! Edit: ok so I created another field, integer in my schema just for testing. I created an entry, saved it, and edited it. this time the same thing happened!

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  • Importing from referenced assembly - MEF

    - by cmaduro
    I have the following simplified code: namespace Silverbits.Applications { public partial class SilverbitsApplication : Application { [Import("MainPage")] public UserControl MainPage { get { return RootVisual as UserControl; } set { RootVisual = value; } } public SilverbitsApplication() { this.Startup += this.SilverbitsApplication_StartUp; this.Exit += new EventHandler(SilverbitsApplication_Exit); this.UnhandledException += this.SilverbitsApplication_UnhandledException; InitializeComponent(); } private void SilverbitsApplication_StartUp(object sender, StartupEventArgs e) { CompositionInitializer.SatisfyImports(this); } } namespace Manpower4U { public class App : SilverbitsApplication { public App() : base() { } } } namespace Manpower4U { [Export("MainPage")] public partial class MainPage : UserControl { public MainPage() { InitializeComponent(); } } } The idea is that I have a Silverbits Library which is a completely different solution. And I have Manpower4U silverlight application that references my Silverbits library. I want to export MainPage from Manpower4U and set it to the RootVisual in my SilverbitsApplication class. SilverbitsApplication class is basically App.xaml/App.cs from the silverlight application, only I put it in a class library and subclassed App.cs file in Manpower4U, which is now the entry point of Manpower4U. MEF cannot resolve the import. How do I get this to work?

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  • Is my method for avoiding dynamic_cast<> faster than dynamic_cast<> itself ?

    - by ereOn
    Hi, I was answering a question a few minutes ago and it raised to me another one: In one of my projects, I do some network message parsing. The messages are in the form of: [1 byte message type][2 bytes payload length][x bytes payload] The format and content of the payload are determined by the message type. I have a class hierarchy, based on a common class Message. To instanciate my messages, i have a static parsing method which gives back a Message* depending on the message type byte. Something like: Message* parse(const char* frame) { // This is sample code, in real life I obviously check that the buffer // is not NULL, and the size, and so on. switch(frame[0]) { case 0x01: return new FooMessage(); case 0x02: return new BarMessage(); } // Throw an exception here because the mesage type is unknown. } I sometimes need to access the methods of the subclasses. Since my network message handling must be fast, I decived to avoid dynamic_cast<> and I added a method to the base Message class that gives back the message type. Depending on this return value, I use a static_cast<> to the right child type instead. I did this mainly because I was told once that dynamic_cast<> was slow. However, I don't know exactly what it really does and how slow it is, thus, my method might be as just as slow (or slower) but far more complicated. What do you guys think of this design ? Is it common ? Is it really faster than using dynamic_cast<> ? Any detailed explanation of what happen under the hood when one use dynamic_cast<> is welcome !

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  • Haskell: "how much" of a type should functions receive? and avoiding complete "reconstruction"

    - by L01man
    I've got these data types: data PointPlus = PointPlus { coords :: Point , velocity :: Vector } deriving (Eq) data BodyGeo = BodyGeo { pointPlus :: PointPlus , size :: Point } deriving (Eq) data Body = Body { geo :: BodyGeo , pict :: Color } deriving (Eq) It's the base datatype for characters, enemies, objects, etc. in my game (well, I just have two rectangles as the player and the ground right now :p). When a key, the characters moves right, left or jumps by changing its velocity. Moving is done by adding the velocity to the coords. Currently, it's written as follows: move (PointPlus (x, y) (xi, yi)) = PointPlus (x + xi, y + yi) (xi, yi) I'm just taking the PointPlus part of my Body and not the entire Body, otherwise it would be: move (Body (BodyGeo (PointPlus (x, y) (xi, yi)) wh) col) = (Body (BodyGeo (PointPlus (x + xi, y + yi) (xi, yi)) wh) col) Is the first version of move better? Anyway, if move only changes PointPlus, there must be another function that calls it inside a new Body. I explain: there's a function update which is called to update the game state; it is passed the current game state, a single Body for now, and returns the updated Body. update (Body (BodyGeo (PointPlus xy (xi, yi)) wh) pict) = (Body (BodyGeo (move (PointPlus xy (xi, yi))) wh) pict) That tickles me. Everything is kept the same within Body except the PointPlus. Is there a way to avoid this complete "reconstruction" by hand? Like in: update body = backInBody $ move $ pointPlus body Without having to define backInBody, of course.

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  • PHP: tips/resources/patterns for learning to implement a basic ORM

    - by BoltClock
    I've seen various MVC frameworks as well as standalone ORM frameworks for PHP, as well as other ORM questions here; however, most of the questions ask for existing frameworks to get started with, which is not what I'm looking for. (I have also read this SO question but I'm not sure what to make of it, and the answers are vague.) Instead, I figured I'd learn best by getting my hands dirty and actually writing my own ORM, even a simple one. Except I don't really know how to get started, especially since the code I see in other ORMs is so complicated. With my PHP 5.2.x (this is important) MVC framework I have a basic custom database abstraction layer, that has: Very simple methods like connect($host, $user, $pass, $base), query($sql, $binds), etc Subclasses for each DBMS that it supports A class (and respective subclasses) to represent SQL result sets But does not have: Active Record functionality, which I assume is an ORM thing (correct me if I'm wrong) I've read up a little about ORM, and from my understanding they provide a means to further abstract data models from the database itself by representing data as nothing more than PHP-based classes/objects; again, correct me if I am wrong or have missed out in any way. Still, I'd like some simple tips from anyone else who's dabbled more or less with ORM frameworks. Is there anything else I need to take note of, simple example code for me to refer to, or resources I can read? Thanks a lot in advance!

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  • Granite DS Actionscript Code Generation Ant cannot find class error

    - by Roaders
    I am trying to get my Ant build to run the granite DS Actionscript code generation task and am running into some problems. At the moment I am getting this error: BUILD FAILED C...\build.xml:62: Could not load Java class file: SampleDTOOne.class So the .class files are obviously being found. I am not however sure if this error means that the it cannot load the .class file or that it cannot find the actual java source code. My Ant task definition looks like this: <classpath> <pathelement location="C.../src/packages/" /> </classpath> <fileset dir="${base.build.dir}/jc/classes/gpbit/packageName"> <include name="*.class" /> </fileset> </gas3> I have tried many different values for the classpath but cannot get anythign to work. I do not like the path that I am using to find the .class files but again at the moment this is the only one I can get to work. None of the variables seem to make it any easier to get to this location. The fileset is definitely working as it definitely found the .clas files to include the name in the error message. More detailed error message: [gas3] Using output dir: C...trunk\plugin\build/etc/src/as3 [gas3] Using classpath: C...\trunk\plugin\src\packages [gas3] Loading all Java classes referenced by inner fileset(s) { [gas3] java.lang.ClassNotFoundException: SampleDTOOne [gas3] at org.apache.tools.ant.AntClassLoader.findClassInComponents(AntClassLoader.java:1361) any help much appreciated

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  • How do I POST/GET from rails to API with either ActiveResource or rest-client (preferred)?

    - by Angela
    Hi, this is a pretty basic question but I'm not entirely clear how to do this. I am trying to use a third-party service that has RESTful service. The service is called Postful. But I'm not clear what exactly to do? I've looked at ActiveResource (http://api.rubyonrails.org/classes/ActiveResource/Base.html) and rest-client, but I'm still not clear exactly what steps, code, and files to create. http://www.postful.com/service/mail is one of the services (details found http://www.postful.com/developer/guide#rest ), but to upload an image I have to post the following (but I'm not sure how I actually do this?). Thanks! > http://www.postful.com/service/upload > > Be sure to include the Content-Type > and Content-Length headers and the > image itself as the body of the > request. > > POST /upload HTTP/1.0 Content-Type: > application/octet-stream > Content-Length: 301456 > > ... file content here ... > > If the upload is successful, you will > receive a response like the following: > > <?xml version="1.0" encoding="UTF-8"?> > <upload> > <id>290797321.waltershandy.2</id> > </upload>

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  • How to allow one thread to mutate an array property while another thread iterates on a copy of the a

    - by Steve918
    I would like to implement an observer pattern in Objective-C where the observer implements an interface similar to SKPaymentTransactionObserver and the observable class just extends my base observable. My observable class looks something like what is below. Notice I'm making copies of the observers before enumeration to avoid throwing an exception . I've tried adding an NSLock around add observers and notify observers, but I run into a deadlock. What would be the proper way to handle concurrency when observers are being added as notifications are being sent? @implementation Observable -(void)notifyObservers:(SEL)selector { @synchronized(self) { NSSet* observer_copy = [observers copy]; for (id observer in observer_copy) { if([observer respondsToSelector: selector]) { [observer performSelector: selector]; } } [observer_copy release]; } } -(void)notifyObservers:(SEL)selector withObject:(id)arg1 withObject:(id)arg2 { @synchronized(self) { NSSet* observer_copy = [observers copy]; for (id observer in observer_copy) { if([observer respondsToSelector: selector]) { [observer performSelector: selector withObject: arg1 withObject: arg2]; } } [observer_copy release]; } } -(void)addObserver:(id)observer { @synchronized(self) { [observers addObject: observer]; } } -(void)removeObserver:(id)observer { @synchronized(self) { [observers removeObject: observer]; } }

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  • Simplifying Testing through design considerations while utilizing dependency injection

    - by Adam Driscoll
    We are a few months into a green-field project to rework the Logic and Business layers of our product. By utilizing MEF (dependency injection) we have achieved high levels of code coverage and I believe that we have a pretty solid product. As we have been working through some of the more complex logic I have found it increasingly difficult to unit test. We are utilizing the CompositionContainer to query for types required by these complex algorithms. My unit tests are sometimes difficult to follow due to the lengthy mock object setup process that must take place, just right, to allow for certain circumstances to be verified. My unit tests often take me longer to write than the code that I'm trying to test. I realize this is not only an issue with dependency injection but with design as a whole. Is poor method design or lack of composition to blame for my overly complex tests? I've tried base classing tests, creating commonly used mock objects and ensuring that I utilize the container as much as possible to ease this issue but my tests always end up quite complex and hard to debug. What are some tips that you've seen to keep such tests concise, readable, and effective?

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  • How can I work out what events are being waited for with WinDBG in a kernel debug session

    - by Benj
    I'm a complete WinDbg newbie and I've been trying to debug a WindowsXP problem that a customer has sent me where our software and some third party software prevent windows from logging off. I've reproduced the problem and have verified that only when our software and the customers software are both installed (although not necessarily running at logoff) does the log off problem occur. I've observed that WM_ENDSESSION messages are not reaching the running windows when the user tries to log off and I know that the third party software uses a kernel driver. I've been looking at the processes in WinDbg and I know that csrss.exe would normally send all the windows a WM_ENDSESSION message. When I ran: !process 82356020 6 To look at csrss.exe's stack I can see: WARNING: Frame IP not in any known module. Following frames may be wrong. 00000000 00000000 00000000 00000000 00000000 0x7c90e514 THREAD 8246d998 Cid 0248.02a0 Teb: 7ffd7000 Win32Thread: e1627008 WAIT: (WrUserRequest) UserMode Non-Alertable 8243d9f0 SynchronizationEvent 81fe0390 SynchronizationEvent Not impersonating DeviceMap e1004450 Owning Process 82356020 Image: csrss.exe Attached Process N/A Image: N/A Wait Start TickCount 1813 Ticks: 20748 (0:00:05:24.187) Context Switch Count 3 LargeStack UserTime 00:00:00.000 KernelTime 00:00:00.000 Start Address 0x75b67cdf Stack Init f80bd000 Current f80bc9c8 Base f80bd000 Limit f80ba000 Call 0 Priority 14 BasePriority 13 PriorityDecrement 0 DecrementCount 0 Kernel stack not resident. ChildEBP RetAddr Args to Child f80bc9e0 80500ce6 00000000 8246d998 804f9af2 nt!KiSwapContext+0x2e (FPO: [Uses EBP] [0,0,4]) f80bc9ec 804f9af2 804f986e e1627008 00000000 nt!KiSwapThread+0x46 (FPO: [0,0,0]) f80bca24 bf80a4a3 00000002 82475218 00000001 nt!KeWaitForMultipleObjects+0x284 (FPO: [Non-Fpo]) f80bca5c bf88c0a6 00000001 82475218 00000000 win32k!xxxMsgWaitForMultipleObjects+0xb0 (FPO: [Non-Fpo]) f80bcd30 bf87507d bf9ac0a0 00000001 f80bcd54 win32k!xxxDesktopThread+0x339 (FPO: [Non-Fpo]) f80bcd40 bf8010fd bf9ac0a0 f80bcd64 00bcfff4 win32k!xxxCreateSystemThreads+0x6a (FPO: [Non-Fpo]) f80bcd54 8053d648 00000000 00000022 00000000 win32k!NtUserCallOneParam+0x23 (FPO: [Non-Fpo]) f80bcd54 7c90e514 00000000 00000022 00000000 nt!KiFastCallEntry+0xf8 (FPO: [0,0] TrapFrame @ f80bcd64) This waitForMultipleObjects looks interesting because I'm wondering if csrss.exe is waiting on some event which isn't arriving to allow the logoff. Can anyone tell me how I might find out what event it's waiting for anything else I might do to further investigate the problem?

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  • TortoiseSVN lists files as modified, but they are identical

    - by BJ Safdie
    I am merging a hot fix from our QA branch back into our Dev branch. Five files have changed. I do a fresh checkout of the Dev branch. I then do a merge (range of revisions) from QA into the Dev working copy. It brings in five files and there is a conflict on an external and ignore property -- which I resolve by "using local" (dev). When I check modifications or commit, I expect to see the five files I merged as the only changes. However, I get close to 700 "modified" files showing up in the commit dialog. If I select one of these file and "Compare with base," WinMerge comes up and says the "files are identical." I have tried this with the file dates set to "last committed" and not. Why are all of these files showing up as modified, when they are identical? What in the merge is causing this? How do I prevent SVN/TortoiseSVN from getting confused this way in the future?

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  • WPF View/ViewModels using Generics- how?

    - by Investor5555
    New to WPF, so please bear with me... Suppose I have 2 tables in SQL Thing OtherThing Both have the exact same fields: ID (int) Name (string) Description (string) IsActive (bit/bool) DateModified (DateTime) So, I want to create one Model (not two) and do something like this: BaseModel<T>() { public int ID {get;set;} ... } etc. (of course, using the INotifyPropertyChanged, just trying to keep the code simple). I want to be able to create a BaseView and BaseViewModel that would work with whatever model conforms to the Thing/OtherThing. I am really at a loss as to what to do here to make this generic, so I don't have to have a ThingView/ThingViewModel and a OtherThingView/OtherThingViewModel... It seems that this should be simple, but I cannot seem to figure it out. Does anyone have a code example where they could interchange various items from a dropdown list using one view, one ViewModel, and one base datamodel (and switching out the type from a dropdown)? For example, a combobox has 3 identical table structures for Thing OtherThing SomeThing and on selection changed, I want to pull the data from whatever table was selected, to be able to do standard CRUD operations on any of these 3 tables, without having to create concrete classes for each view/viewmodel.

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  • How do I make a grouped select box grouped by a column for a given model in Formtastic for Rails?

    - by jklina
    In my Rails project I'm using Formtastic to manage my forms. I have a model, Tags, with a column, "group". The group column is just a simple hardcoded way to organize my tags. I will post my Tag model class so you can see how it's organized class Tag < ActiveRecord::Base class Group BRAND = 1 SEASON = 2 OCCASION = 3 CONDITION = 4 SUBCATEGORY = 5 end has_many :taggings, :dependent => :destroy has_many :plaggs, :through => :taggings has_many :monitorings, :as => :monitorizable validates_presence_of :name, :group validates_uniqueness_of :name, :case_sensitive => false def self.brands(options = {}) self.all({ :conditions => { :group => Group::BRAND } }.merge(options)) end def self.seasons(options = {}) self.all({ :conditions => { :group => Group::SEASON } }.merge(options)) end def self.occasions(options = {}) self.all({ :conditions => { :group => Group::OCCASION } }.merge(options)) end def self.conditions(options = {}) self.all({ :conditions => { :group => Group::CONDITION } }.merge(options)) end def self.subcategories(options = {}) self.all({ :conditions => { :group => Group::SUBCATEGORY } }.merge(options)) end def self.non_brands(options = {}) self.all({ :conditions => [ "`group` != ? AND `group` != ?", Tag::Group::SUBCATEGORY, Tag::Group::BRAND] }.merge(options)) end end My goal is to use Formtastic to provide a grouped multiselect box, grouped by the column, "group" with the tags that are returned from the non_brands method. I have tried the following: = f.input :tags, :required => false, :as => :select, :input_html => { :multiple => true }, :collection => tags, :selected => sel_tags, :group_by => :group, :prompt => false But I receive the following error: (undefined method `klass' for nil:NilClass) Any ideas where I'm going wrong? Thanks for looking :]

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  • Can I use my Ninject .NET project within Orchard CMS?

    - by Mattias Z
    I am creating a website using Orchard CMS and I have an external .NET project written with Ninject for dependency injection which I would like to use together with a module within Orchard CMS. I know that Orchard uses Autofac for dependency injection and this is causing me problems since I never worked with DI before. I have created a Autofac module UserModule which registers the source UserRegistrationSource and I configured Orchard to load the module like this: OrchardStarter.cs .... builder.RegisterModule(new UserModule()); .... UserModule.cs public class UserModule : Module { protected override void Load(ContainerBuilder builder) { builder.RegisterSource(new UserRegistrationSource()); base.Load(builder); } } UserRegistrationSource.cs public class UserRegistrationSource : IRegistrationSource { public bool IsAdapterForIndividualComponents { get { return false; } } public IEnumerable<IComponentRegistration> RegistrationsFor(Service service, Func<Service, IEnumerable<IComponentRegistration>> registrationAccessor) { var serviceWithType = service as IServiceWithType; if (serviceWithType == null) yield break; var serviceType = serviceWithType.ServiceType; if (!serviceType.IsInterface || !typeof(IUserServices).IsAssignableFrom(serviceType) || serviceType == typeof(IUserServices)) yield break; var registrationBuilder = ... yield return registrationBuilder.CreateRegistration(); } } But now I'm stuck... Should I somehow try to resolve the dependencies in UserRegistrationSource by getting the requested types from the Ninject container (kernel) with Autofac or is this the wrong approach? Or should the Ninject kernel do the resolves for Autofac for the external project?

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  • What is the the relation between programming and mathematics?

    - by Math Grad
    Programmers seem to think that their work is quite mathematical. I understand this when you try to optimize something in performance, find the most efficient alogithm, etc.. But it patently seems false when you look at a billing application for a shop, or a systems software riddled with I/O calls. So what is it exactly? Is computation and associated programming really mathematical? Here I have in mind particularly the words of the philosopher Schopenhauer in mind: That arithmetic is the basest of all mental activities is proved by the fact that it is the only one that can be accomplished by means of a machine. Take, for instance, the reckoning machines that are so commonly used in England at the present time, and solely for the sake of convenience. But all analysis finitorum et infinitorum is fundamentally based on calculation. Therefore we may gauge the “profound sense of the mathematician,” of whom Lichtenberg has made fun, in that he says: “These so-called professors of mathematics have taken advantage of the ingenuousness of other people, have attained the credit of possessing profound sense, which strongly resembles the theologians’ profound sense of their own holiness.” I lifted the above quote from here. It seems that programmers are doing precisely the sort of mechanized base mental activity the grand old man is contemptuous about. So what exactly is the deal? Is programming really the "good" kind of mathematics, or just the baser type, or altogether something else just meant for business not to be confused with a pure discipline?

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