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  • Seperation of business logic

    - by bruno
    Dear all, When I was optimizing my architecture of our applications in our website, I came to a problem that I don't know the best solution for. Now at the moment we have a small dll based on this structure: Database <-> DAL <-> BLL the Dal uses Business Objects to pass to the BLL that will pass it to the applications that uses this dll. Only the BLL is public so any application that includes this dll, can see the bll. In the beginning, this was a good solution for our company. But when we are adding more and more applications on that Dll, the bigger the Bll is getting. Now we dont want that some applications can see Bll-logic from other applications. Now I don't know what the best solution is for that. The first thing I thought was, move and seperate the bll to other dll's which i can include in my application. But then must the Dal be public, so the other dll's can get the data... and that I seems like a good solution. My other soluition, is just to seperate the bll in different namespaces, and just include only the namespaces you need in the applications. But in this solution, you can get directly access to other bll's if you want. So i'm asking for your oppinions. Thx, Bruno

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  • Conditional column values in NSTableView?

    - by velocityb0y
    I have an NSTableView that binds via an NSArrayController to an NSMutableArray. What's in the array are derived classes; the first few columns of the table are bound to properties that exist on the base class. That all works fine. Where I'm running into problem is a column that should only be populated if the row maps to one specific subclass. The property that column is meant to display only exists in that subclass, since it makes no sense in terms of the base class. The user will know, from the first two columns, why the third column's cell is populated/editable or not. The binding on the third column's value is on arrangedObjects, with a model path of something like "foo.name" where foo is the property on the subclass. However, this doesn't work, as the other subclasses in the hierarchy are not key-value compliant for foo. It seems like my only choice is to have foo be a property on the base class so everybody responds to it, but this clutters up the interfaces of the model objects. Has anyone come up with a clean design for this situation? It can't be uncommon (I'm a relative newcomer to Cocoa and I'm just learning the ins and outs of bindings.)

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  • Silverlight - C# and LINQ - Ordering By Multiple Fields

    - by user70192
    Hello, I have an ObservableCollection of Task objects. Each Task has the following properties: AssignedTo Category Title AssignedDate I'm giving the user an interface to select which of these fields they was to sort by. In some cases, a user may want to sort by up to three of these properties. How do I dynamically build a LINQ statement that will allow me to sort by the selected fields in either ascending or descending order? Currently, I'm trying the following, but it appears to only sort by the last sort applied: var sortedTasks = from task in tasks select task; if (userWantsToSortByAssignedTo == true) { if (sortByAssignedToDescending == true) sortedTasks = sortedTasks.OrderByDescending(t => t.AssignedTo); else sortedTasks = sortedTasks.OrderBy(t => t.AssignedTo); } if (userWantsToSortByCategory == true) { if (sortByCategoryDescending == true) sortedTasks = sortedTasks.OrderByDescending(t => t.Category); else sortedTasks = sortedTasks.OrderBy(t => t.Category); } Is there an elegant way to dynamicaly append order clauses to a LINQ statement?

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  • Zend_Auth and database session SaveHandler

    - by takeshin
    I have created Zend_Auth adapter implementing Zend_Auth_Adapter_Interface (similar to Pádraic's adapter) and created simple ACL plugin. Everything works fine with default session handler. So far, so good. As a next step I have created custom Session SaveHandler to persist session data in the database. My implementation is very similar to this one from parables-demo. Seems that everything is working fine. Session data are properly saved to the database, session objects are serialized, but authentication does not work when I enable this custom SaveHandler. I have debugged the authentication and all works fine up till the next request, when the authentication data are lost. I suspected, that is has something to do with the fact, that I use $adapter->write($object) instead $adapter->write($string), but the same happens with strings. I'm bootstrapping Zend_Application_Resource_Session in the first Bootstrap method, as early as possible. Does Zend_Auth need any extra configuration to persist data in the database? Why the authentity is being lost?

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  • Components don't show in custom JPanel/JComponent

    - by Bart van Heukelom
    I've created a custom swing component. I can see it (the grid from the paint method is drawn), but the buttons that are added (verified by println) aren't shown. What am I doing wrong? Background information: I'm trying to build a tree of visible objects like the Flash/AS3 display list. public class MapPanel extends JComponent { // or extends JPanel, same effect private static final long serialVersionUID = 4844990579260312742L; public MapPanel(ShapeMap map) { setBackground(Color.LIGHT_GRAY); setPreferredSize(new Dimension(1000,1000)); setLayout(null); for (Layer l : map.getLayers()) { // LayerView layerView = new LayerView(l); // add(layerView); System.out.println(l); JButton test = new JButton(l.getName()); add(test); validate(); } } @Override protected void paintComponent(Graphics g) { // necessary? super.paintComponent(g); // background g.setColor(getBackground()); g.fillRect(0, 0, getWidth(), getHeight()); // grid g.setColor(Color.GRAY); for (double x = 0; x < getWidth(); x += 10) { g.drawLine((int)x, 0, (int)x, getHeight()); } for (double y = 0; y < getHeight(); y += 10) { g.drawLine(0, (int)y, getWidth(), (int)y); } } }

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  • unable to set fields of a collection-property elements after changing their order (elements becoming

    - by Jaroslav Záruba
    Hello I want to change order of objects in a collection, and then to access+modify fields of those items. Unfortunately the items somehow become 'deleted'. This is what I do... if(someCondition) { MainEvent mainEvent = pm.getObjectById(MainEvent.class, mainEventKey); /* * events in the original order * MainEvent.subEvents field is not in default fetch group, * therefore I also tried to add the named group into the * persistenceManeger fetch plan, no difference * (mainEvent is not instance of the Event sub/class BTW) */ List<Event> subEvents = mainEvent.getSubEvents(); // re-arrange the events according to keysOrdered { Map<Key, Event> eventMap = new HashMap<Key, Event>(); for(Event event : subEvents) eventMap.put(event.getKey(), event); List<Event> eventsOrdered = new LinkedList<Event>(); for(Key eventKey : keysOrdered) eventsOrdered.add(eventMap.put(eventKey, eventMap.get(eventKey))); // } // put the re-arranged items back into the collection property { subEvents.clear(); subEvents.addAll(eventsOrdered); // } pm.makePersistent(mainEvent); eventsOrdered = subEvents; } else eventsOrdered = getEventsUsingAlternateApproach(); /* * so by now the mainEvent variable does not exist; * could it be this lead the persistence manager to mark * my events as abandoned/obsolete/invalid/deleted...? */ for(Event event : eventsOrdered) event.setDate(new Date()); // -> "Cannot write fields to a deleted object" What am I doing wrong please?

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  • ReaderWriterLockSlim and Pulse/Wait

    - by Jono
    Is there an equivalent of Monitor.Pulse and Monitor.Wait that I can use in conjunction with a ReaderWriterLockSlim? I have a class where I've encapsulated multi-threaded access to an underlying queue. To enqueue something, I acquire a lock that protects the underlying queue (and a couple of other objects) then add the item and Monitor.Pulse the locked object to signal that something was added to the queue. public void Enqueue(ITask task) { lock (mutex) { underlying.Enqueue(task); Monitor.Pulse(mutex); } } On the other end of the queue, I have a single background thread that continuously processes messages as they arrive on the queue. It uses Monitor.Wait when there are no items in the queue, to avoid unnecessary polling. (I consider this to be good design, but any flames (within reason) are welcome if they help me learn otherwise.) private void DequeueForProcessing(object state) { while (true) { ITask task; lock (mutex) { while (underlying.Count == 0) { Monitor.Wait(mutex); } task = underlying.Dequeue(); } Process(task); } } As more operations are added to this class (requiring read-only access to the lock protected underlying), someone suggested using ReaderWriterLockSlim. I've never used the class before, and assuming it can offer some performance benefit, I'm not against it, but only if I can keep the Pulse/Wait design.

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  • Transaction to find an entity - locks all entities of that type?

    - by user246114
    Hi, Reading the docs for transactions: http://code.google.com/appengine/docs/java/datastore/transactions.html An example provided shows one way to make an instance of an object: try { tx.begin(); Key k = KeyFactory.createKey("SalesAccount", id); try { account = pm.getObjectById(Employee.class, k); } catch (JDOObjectNotFoundException e) { account = new SalesAccount(); account.setId(id); } ... When the above transaction gets executed, it will probably block all other write attempts on Account objects? I'm wondering because I'd like to have a user signup which checks for a username or email already in use: tx.begin(); "select from User where mUsername == str1 LIMIT 1"; if (count > 0) { throw new Exception("username already in use!"); } "select from User where mEmail == str1 LIMIT 1"; if (count > 0) { throw new Exception("email already in use!"); } pm.makePersistent(user(username, email)); // ok. tx.commit(); but the above would be even more time consuming I think, making an even worse bottleneck? Am I understanding what will happen correctly? Thanks

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  • How to fix error - "@interface interfaceName : someEnumeration" gives error "cannot find interface '

    - by Paul V
    How can I solve "cannot find interface declaration 'someEnumeration', superclass of 'interfaceName'" error? What steps will reproduce the problem? Compiling Wsdl2ObjC Targeting groupwise.wsdl file Fixing non-valid file names of output csource code like ".h" + ".m" and objects inside source files Moving up one of the @interface BEFORE it was used futher in code! What is the expected output? Something working What do you see instead? 33 errors. "Inherited" from only 3 similar Inheritances of a typedef enum object by a class. All errors are typical: typedef enum types_StatusTrackingOptions { types_StatusTrackingOptions_none = 0, types_StatusTrackingOptions_None, types_StatusTrackingOptions_Delivered, types_StatusTrackingOptions_DeliveredAndOpened, types_StatusTrackingOptions_All, } types_StatusTrackingOptions; types_StatusTrackingOptions types_StatusTrackingOptions_enumFromString(NSString *string); NSString * types_StatusTrackingOptions_stringFromEnum(types_StatusTrackingOptions enumValue); @interface types_StatusTracking : types_StatusTrackingOptions { ... and here I'm having error "cannot find interface declaration for 'types_StatusTrackingOptions', superclass of 'types_StatusTracking'". What version of the product are you using? On what operating system? Wsdl2ObjC - rev 168, OS - Mac OS X 10.6.2, iPhone SDK - 3.2, Simulator - v. 3.1.2 - 3.1.3, wsdl - for GroupWise v.8, NDK released 2008-12-23, wsdl and xsd files are attached. P.S. GroupWise.wsdl + .xsd files could be downloaded from http://code.google.com/p/wsdl2objc/issues/detail?id=99

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  • Glitch when moving camera in OpenGL

    - by CG
    I am writing a tile-based game engine for the iPhone and it works in general apart from the following glitch. Basically, the camera will always keep the player in the centre of the screen, and it moves to follow the player correctly and draws everything correctly when stationary. However whilst the player is moving, the tiles of the surface the player is walking on glitch as shown: Compared to the stationary (correct): Does anyone have any idea why this could be? Thanks for the responses so far. Floating point error was my first thought also and I tried slightly increasing the size of the tiles but this did not help. Changing glClearColor to red still leaves black gaps so maybe it isn't floating point error. Since the tiles in general will use different textures, I don't know if vertex arrays can be used (I always thought that the same texture had to be applied to everything in the array, correct me if I'm wrong), and I don't think VBO is available in OpenGL ES. Setting the filtering to nearest neighbour improved things but the glitch still happens every ten frames or so, and the pixelly result means that this solution is not viable anyway. The main difference between what I'm doing now and what I've done in the past is that this time I am moving the camera rather than the stationary objects in the world (i.e. the tiles, the player is still being moved). The code I'm using to move the camera is: void Camera::CentreAtPoint( GLfloat x, GLfloat y ) { glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrthof(x - size.x / 2.0f, x + size.x / 2.0f, y + size.y / 2.0f, y - size.y / 2.0f, 0.01f, 5.0f); glMatrixMode(GL_MODELVIEW); } Is there a problem with doing things this way and if so is there a solution?

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  • Invoking a method overloaded where all arguments implement the same interface

    - by double07
    Hello, My starting point is the following: - I have a method, transform, which I overloaded to behave differently depending on the type of arguments that are passed in (see transform(A a1, A a2) and transform(A a1, B b) in my example below) - All these arguments implement the same interface, X I would like to apply that transform method on various objects all implementing the X interface. What I came up with was to implement transform(X x1, X x2), which checks for the instance of each object before applying the relevant variant of my transform. Though it works, the code seems ugly and I am also concerned of the performance overhead for evaluating these various instanceof and casting. Is that transform the best I can do in Java or is there a more elegant and/or efficient way of achieving the same behavior? Below is a trivial, working example printing out BA. I am looking for examples on how to improve that code. In my real code, I have naturally more implementations of 'transform' and none are trivial like below. public class A implements X { } public class B implements X { } interface X { } public A transform(A a1, A a2) { System.out.print("A"); return a2; } public A transform(A a1, B b) { System.out.print("B"); return a1; } // Isn't there something better than the code below??? public X transform(X x1, X x2) { if ((x1 instanceof A) && (x2 instanceof A)) { return transform((A) x1, (A) x2); } else if ((x1 instanceof A) && (x2 instanceof B)) { return transform((A) x1, (B) x2); } else { throw new RuntimeException("Transform not implemented for " + x1.getClass() + "," + x2.getClass()); } } @Test public void trivial() { X x1 = new A(); X x2 = new B(); X result = transform(x1, x2); transform(x1, result); }

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  • How to detect .NET WPF memory leak or GC long run?

    - by Néstor Sánchez A.
    I have the next very strange situation and problem: .NET 4.0 application for diagram editing (WPF). Runs ok in my PC: 8GM RAM, 3.0GHz, i7 quad-core. While creating objects (mostly diagram nodes and connectors, plus all the undo/redo information) the TaskManager show, as expected, some memory usage "jumps" (up and down). These mem-usage "jumps" also remains executing AFTER user interaction ended. Maybe this is the GC cleaning/regorganizing memory? To see what is going on, I've used the Ants mem profiler, but somewhat it prevents those "jumps" to happen after user interaction. PROBLEM: It Freezes/Hangs after seconds or minutes of usage in some slow/weak laptos/netbooks of my beta testers (under 2GHz of speed and under 2GB of RAM). I was thinking of a memory leak, but... EDIT: Also, there is the case that the memory usage grows and grows until collapse (only in slow machines). In a Windows XP Mode machine (VM in Win 7) with only 512MB of RAM Assigned it works fine without mem-usage "jumps" after user interaction (no GC cleaning?!). So, I really have a big trouble because I cannot reproduce the error, only see these strange behaviour (mem jumps), and the tool supposed to show me what is happening is hiding the problem (like the "observer's paradox"). Any ideas on what's happening and how to solve it?

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  • In a class with no virtual methods or superclass, is it safe to assume (address of first member vari

    - by Jeremy Friesner
    Hi all, I made a private API that assumes that the address of the first member-object in the class will be the same as the class's this-pointer... that way the member-object can trivially derive a pointer to the object that it is a member of, without having to store a pointer explicitly. Given that I am willing to make sure that the container class won't inherit from any superclass, won't have any virtual methods, and that the member-object that does this trick will be the first member object declared, will that assumption hold valid for any C++ compiler, or do I need to use the offsetof() operator (or similar) to guarantee correctness? To put it another way, the code below does what I expect under g++, but will it work everywhere? class MyContainer { public: MyContainer() {} ~MyContainer() {} // non-virtual dtor private: class MyContained { public: MyContained() {} ~MyContained() {} // Given that the only place Contained objects are declared is m_contained // (below), will this work as expected on any C++ compiler? MyContainer * GetPointerToMyContainer() { return reinterpret_cast<MyContainer *>(this); } }; MyContained m_contained; // MUST BE FIRST MEMBER ITEM DECLARED IN MyContainer int m_foo; // other member items may be declared after m_contained float m_bar; };

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  • Django - foreignkey problem

    - by realshadow
    Hey, Imagine you have this model: class Category(models.Model): node_id = models.IntegerField(primary_key = True) type_id = models.IntegerField(max_length = 20) parent_id = models.IntegerField(max_length = 20) sort_order = models.IntegerField(max_length = 20) name = models.CharField(max_length = 45) lft = models.IntegerField(max_length = 20) rgt = models.IntegerField(max_length = 20) depth = models.IntegerField(max_length = 20) added_on = models.DateTimeField(auto_now = True) updated_on = models.DateTimeField(auto_now = True) status = models.IntegerField(max_length = 20) node = models.ForeignKey(Category_info, verbose_name = 'Category_info', to_field = 'node_id' The important part is the foreignkey. When I try: Category.objects.filter(type_id = type_g.type_id, parent_id = offset, status = 1) I get an error that get returned more than category, which is fine, because it is supposed to return more than one. But I want to filter the results trough another field, which would be type id (from the second Model) Here it is: class Category_info(models.Model): objtree_label_id = models.AutoField(primary_key = True) node_id = models.IntegerField(unique = True) language_id = models.IntegerField() label = models.CharField(max_length = 255) type_id = models.IntegerField() The type_id can be any number from 1 - 5. I am desparately trying to get only one result where the type_id would be number 1. Here is what I want in sql: SELECT n.*, l.* FROM objtree_nodes n JOIN objtree_labels l ON (n.node_id = l.node_id) WHERE n.type_id = 15 AND n.parent_id = 50 AND l.type_id = 1 Any help is GREATLY appreciated. Regards

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  • Implicit Type Conversions in Reflection

    - by bradhe
    So I've written a quick bit of code to help quickly convert between business objects and view models. Not to pimp my own blog, but you can find the details here if you're interested or need to know. One issue I've run in to is that I have a custom collection type, ProductCollection, and I need to turn that in to a string[] in on my model. Obviously, since there is no default implicit cast, I'm getting an exception in my contract converter. So, I thought I would write the next little bit of code and that should solve the problem: public static implicit operator string[](ProductCollection collection) { var list = new List<string>(); foreach (var product in collection) { if (product.Id == null) { list.Add(null); } else { list.Add(product.Id.ToString()); } } return list.ToArray(); } However, it still fails with the same cast exception. I'm wondering if it has something to do with being in reflection? If so, is there anything that I can do here?? I'm open to architectural solutions, too!

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  • c++ Design pattern for CoW, inherited classes, and variable shared data?

    - by krunk
    I've designed a copy-on-write base class. The class holds the default set of data needed by all children in a shared data model/CoW model. The derived classes also have data that only pertains to them, but should be CoW between other instances of that derived class. I'm looking for a clean way to implement this. If I had a base class FooInterface with shared data FooDataPrivate and a derived object FooDerived. I could create a FooDerivedDataPrivate. The underlying data structure would not effect the exposed getters/setters API, so it's not about how a user interfaces with the objects. I'm just wondering if this is a typical MO for such cases or if there's a better/cleaner way? What peeks my interest, is I see the potential of inheritance between the the private data classes. E.g. FooDerivedDataPrivate : public FooDataPrivate, but I'm not seeing a way to take advantage of that polymorphism in my derived classes. class FooDataPrivate { public: Ref ref; // atomic reference counting object int a; int b; int c; }; class FooInterface { public: // constructors and such // .... // methods are implemented to be copy on write. void setA(int val); void setB(int val); void setC(int val); // copy constructors, destructors, etc. all CoW friendly private: FooDataPrivate *data; }; class FooDerived : public FooInterface { public: FooDerived() : FooInterface() {} private: // need more shared data for FooDerived // this is the ???, how is this best done cleanly? };

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  • NSOperations or NSThread for bursts of smaller tasks that continuously cancel each other?

    - by RickiG
    Hi I would like to see if I can make a "search as you type" implementation, against a web service, that is optimized enough for it to run on an iPhone. The idea is that the user starts typing a word; "Foo", after each new letter I wait XXX ms. to see if they type another letter, if they don't, I call the web service using the word as a parameter. The web service call and the subsequent parsing of the result I would like to move to a different thread. I have written a simple SearchWebService class, it has only one public method: - (void) searchFor:(NSString*) str; This method tests if a search is already in progress (the user has had a XXX ms. delay in their typing) and subsequently stops that search and starts a new one. When a result is ready a delegate method is called: - (NSArray*) resultsReady; I can't figure out how to get this functionality 'threaded'. If I keep spawning new threads each time a user has a XXX ms. delay in the typing I end up in a bad spot with many threads, especially because I don't need any other search, but the last one. Instead of spawning threads continuously, I have tried keeping one thread running in the background all the time by: - (void) keepRunning { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; SearchWebService *searchObj = [[SearchWebService alloc] init]; [[NSRunLoop currentRunLoop] run]; //keeps it alive [searchObj release]; [pool release]; } But I can't figure out how to access the "searchFor" method in the "searchObj" object, so the above code works and keeps running. I just can't message the searchObj or retrieve the resultReady objects? Hope someone could point me in the right direction, threading is giving me grief:) Thank you.

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  • WPF data-bound ComboBox only shows first item of ItemsSource list

    - by Mark
    Hi all, I'm sure I'm doing something stupid but for the life of me I can't think of right now. I have a ComboBox that is data-bound to a list of Layout objects. The list is initially empty but things are added over time. When the list is updated by the model the first time, this update reflects properly in the ComboBox. However, subsequent updates never show up in the ComboBox even though I can see that the list itself contains these items. Since the first update works, I know the data-binding is OK - so what am I doing wrong here? Here's the XAML (abridged): <Grid HorizontalAlignment="Stretch"> <ComboBox ItemsSource="{Binding Path=SavedLayouts, diagnostics:PresentationTraceSources.TraceLevel=High}" DisplayMemberPath="Name" SelectedValuePath="Name" SelectedItem="{Binding LoadLayout}" Height="25" Grid.Row="1" Grid.Column="0"></ComboBox> </Grid> And the related part of the model: public IList<Layout> SavedLayouts { get { return _layouts; } } public Layout SaveLayout( String data_ ) { Layout theLayout = new Layout( SaveLayoutName ); _layouts.Add( theLayout ); try { return theLayout; } finally { PropertyChangedEventHandler handler = PropertyChanged; if( handler != null ) { handler( this, new PropertyChangedEventArgs( "SavedLayouts" ) ); } } } And finally, the layout class (abridged): public class Layout { public String Name { get; private set; } } In the output window, I can see the update occurring: System.Windows.Data Warning: 91 : BindingExpression (hash=64564967): Got PropertyChanged event from TickerzModel (hash=43624632) System.Windows.Data Warning: 97 : BindingExpression (hash=64564967): GetValue at level 0 from TickerzModel (hash=43624632) using RuntimePropertyInfo(SavedLayouts): List`1 (hash=16951421 Count=11) System.Windows.Data Warning: 76 : BindingExpression (hash=64564967): TransferValue - got raw value List`1 (hash=16951421 Count=11) System.Windows.Data Warning: 85 : BindingExpression (hash=64564967): TransferValue - using final value List`1 (hash=16951421 Count=11) But I get do not get this 11th item in the ComboBox. Any ideas?

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  • Analyzing an IronPython Scope

    - by Vercinegetorix
    I'm trying to write C# code with an embedded IronPython script. Then want to analyze the contents of the script, i.e. list all variables, functions, class and their members/methods. There's an easy way to start, assuming I've got a scope defined and code executed in it already: dynamic variables=pyScope.GetVariables(); foreach (string v in variables) { dynamic dynamicV=pyScope.GetVariable(); /*seems to return everything. variables, functions, classes, instances of classes*/ } But how do I figure out what the type of a variable is? For the following python 'objects', dynamicV.GetType() will return different values: x=5 --system.Int32 y="asdf" --system.String def func():... --IronPython.Runtime.PythonFunction z=class() -- IronPython.Runtime.Types.OldInstance, how can I identify what the actual python class is? class NewClass -- throws an error, GetType() is unavailable. This is almost what I'm looking for. I could capture the exception thrown when unavailable and assume it's a class declaration, but that seems unclean. Is there a better approach? To discover the members/methods of a class it looks like I can use: ObjectOperations op = pyEngine.Operations; object instance = op.Call("className"); foreach (string j in op.GetMemberNames("className")) { object member=op.GetMember(instance, j); Console.WriteLine(member.GetType()); /*once again, GetType() provides some info about the type of the member, but returns null sometimes*/ } Also, how do I get the parameters to a method? Thanks!

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  • Populate a tree from Hierarchical data using 1 LINQ statement

    - by Midhat
    Hi. I have set up this programming exercise. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication2 { class DataObject { public int ID { get; set; } public int ParentID { get; set; } public string Data { get; set; } public DataObject(int id, int pid, string data) { this.ID = id; this.ParentID = pid; this.Data = data; } } class TreeNode { public DataObject Data {get;set;} public List<DataObject> Children { get; set; } } class Program { static void Main(string[] args) { List<DataObject> data = new List<DataObject>(); data.Add(new DataObject(1, 0, "Item 1")); data.Add(new DataObject(2, 0, "Item 2")); data.Add(new DataObject(21, 2, "Item 2.1")); data.Add(new DataObject(22, 2, "Item 2.2")); data.Add(new DataObject(221, 22, "Item 2.2.1")); data.Add(new DataObject(3, 0, "Item 3")); } } } The desired output is a List of 3 treenodes, having items 1, 2 and 3. Item 2 will have a list of 2 dataobjects as its children member and so on. I have been trying to populate this tree (or rather a forest) using just 1 SLOC using LINQ. A simple group by gives me the desired data but the challenge is to organize it in TreeNode objects. Can someone give a hint or an impossibility result for this?

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  • CORBA on MacOS X (Cocoa)

    - by user8472
    I am currently looking into different ways to support distributed model objects (i.e., a computational model that runs on several different computers) in a project that initially focuses on MacOS X (using Cocoa). As far as I know there is the possibility to use the class cluster around NSProxy. But there also seem to be implementations of CORBA around with Objective-C support. At a later time there may be the need to also support/include Windows machines. In that case I would need to use something like Gnustep on the Windows side (which may be an option, if it works well) or come up with a combination of both technologies. Or write something manually (which is, of course, the least desirable option). My questions are: If you have experience with both technologies (Cocoa native infrastructure vs. CORBA) can you point out some key features/issues of either approach? Is it possible to use Gnustep with Cocoa in the way explained above? Is it possible (and reasonably feasible, i.e. simpler than writing a network layer manually) to communicate among all MacOS clients using Cocoa's technology and with Windows clients through CORBA?

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  • Problem importing Oracle .dmp file

    - by BitFiddler
    So I have looked at all the suggested ways of importing .dmp files and non of them seem to answer this question: where does the data go once you import it? Context: I created a user like so: SQL> create user IMPORTER identified by "12345"; SQL> grant connect, unlimited tablespace, resource to IMPORTER; I then ran the 'imp' command as follows: C:\>imp system/password FROMUSER=OVIEDOE TOUSER=IMPORTER file=c:\database1.dmp Now there were 9 .dmp files, after each one it asked me for the next one and then I received the message "Import terminated successfully with warnings." The warning was: Warning: the objects were exported by OVIEDOE, not by you import done in WE8MSWIN1252 character set and AL16UTF16 NCHAR character set export client uses WE8ISO8859P1 character set (possible charset conversion) IMP-00046: using FILESIZE value from export file of 2147483648 Now it says it was terminated successfully so my assumption (I am new to oracle so this may be wrong) is that the data was loaded. However, when I use SQL developer to connect to the database and look under the 'tables' node under the IMPORTER user, there is nothing there. What is going on? Did the data load? If so, where can I find it?

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  • Formating Date in Freemarker to say "Today", "Yesterday", etc.

    - by egervari
    Is there a way in freemarker to compare dates to test if the date is today or yesterday... or do I have to write code in Java to do these tests? I basically want to do this: <#------------------------------------------------------------------------------ formatDate -------------------------------------------------------------------------------> <#macro formatDate date showTime=true> <#if date??> <span class="Date"> <#if date?is_today> Today <#elseif date?is_yesterday> Yesterday <#else> ${date?date} </#if> </span> <#if showTime> <span class="Time">${date?time}</span> </#if> </#if> </#macro> EDIT: My best guess to implement this is to pass "today" and "yesterday" into the model for the pages that use this function and then compare the date values against these 2 objects in the model. I am out of out of options, but I'd rather not have to do this for every page that uses this macro. Any other options that are nicer? <#if date??> <span class="Date"> <#if date?date?string.short == today?date?string.short> Today <#elseif date?date?string.short == yesterday?date?string.short> Yesterday <#else> ${date?date} </#if> </span> <#if showTime> <span class="Time">${date?time}</span> </#if> </#if>

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  • Callback function and function pointer trouble in C++ for a BST

    - by Brendon C.
    I have to create a binary search tree which is templated and can deal with any data types, including abstract data types like objects. Since it is unknown what types of data an object might have and which data is going to be compared, the client side must create a comparison function and also a print function (because also not sure which data has to be printed). I have edited some C code which I was directed to and tried to template, but I cannot figure out how to configure the client display function. I suspect variable 'tree_node' of class BinarySearchTree has to be passed in, but I am not sure how to do this. For this program I'm creating an integer binary search tree and reading data from a file. Any help on the code or the problem would be greatly appreciated :) Main.cpp #include "BinarySearchTreeTemplated.h" #include <iostream> #include <fstream> #include <string> using namespace std; /*Comparison function*/ int cmp_fn(void *data1, void *data2) { if (*((int*)data1) > *((int*)data2)) return 1; else if (*((int*)data1) < *((int*)data2)) return -1; else return 0; } static void displayNode() //<--------NEED HELP HERE { if (node) cout << " " << *((int)node->data) } int main() { ifstream infile("rinput.txt"); BinarySearchTree<int> tree; while (true) { int tmp1; infile >> tmp1; if (infile.eof()) break; tree.insertRoot(tmp1); } return 0; } BinarySearchTree.h (a bit too big to format here) http://pastebin.com/4kSVrPhm

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  • Java - How to declare table[i][j] elements as instance variables?

    - by JDelage
    All, I am trying to code a Connect4 game. For this, I have created a P4Game class and a P4Board class which represents the i X j dimensions of the Connect4 board. In P4Game, I have the following: public class P4Game{ //INSTANCE VARIABLES private int nbLines; private int nbColumns; private P4Board [][] position; //CONSTRUCTOR public P4Game(int nbLines, int nbColumns){ this.nbColumns = nbColumns; this.nbLines = nbLines; P4Board [][] position = new P4Board [nbLines][nbColumns]; //Creates the table to receive the instances of the P4Board object.*/ for (int i=0; i<nbLines; i++){ for (int j=0; j<nbColumns; j++){ this.position[i][j] = new P4Board(i,j); //Meant to create each object at (line=i, column=j) } } } This causes a NullPointerException in the nested loops where I mention this.position[i][j]. I reference those objects in other methods of this class so I need them to be instance variables. I suppose the exception is due to the fact that I have not listed the table element position[i][j] as an instance variable at the beginning of the class. my question to people here is (1) is my assumption correct, and if so (2) what would be the syntax to declare instance variables of this form? Thank you all for your help with what I realize is a very basic question. Hopefully it will also benefit other newbies. Cheers, JDelage

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