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  • Deserialize json with json.net c#

    - by 76mel
    Hi, am new to Json so a little green. I have a Rest Based Service that returns a json string; {"treeNode":[{"id":"U-2905","pid":"R","userId":"2905"}, {"id":"U-2905","pid":"R","userId":"2905"}]} I have been playing with the Json.net and trying to Deserialize the string into Objects etc. I wrote an extention method to help. public static T DeserializeFromJSON<T>(this Stream jsonStream, Type objectType) { T result; using (StreamReader reader = new StreamReader(jsonStream)) { JsonSerializer serializer = new JsonSerializer(); try { result = (T)serializer.Deserialize(reader, objectType); } catch (Exception e) { throw; } } return result; } I was expecting an array of treeNode[] objects. But its seems that I can only deserialize correctly if treeNode[] property of another object. public class treeNode { public string id { get; set; } public string pid { get; set; } public string userId { get; set; } } I there a way to to just get an straight array from the deserialization ? Cheers

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  • Animate and form rows, arrays, AS3

    - by VideoDnd
    Question How can I animate and form rows together? Explanation One 'for loop' is for animation, the other 'for loop' is for making rows. I want to understand how to use arrays and create a row of sprite animations. 'for loop' for animation //FRAMES ARRAY //THIS SETS UP MY ANIMATION FOR TIMER EVENT var frames:Array = [ new Frame1(), new Frame2(), new Frame3(), new Frame4(), new Frame5(), new Frame6(), new Frame7(), new Frame8(), new Frame9(), new Frame0(), ]; for each (var frame:Sprite in frames) { addChild(frame); } 'for loop' for rows //THIS MAKES A ROW OF DISPLAY OBJECTS var numberOfClips:Number = 11; var xStart:Number = 0; var yStart:Number = 0; var xVal:Number = xStart; var xOffset:Number = 2; for (var $:Number=0; $<numberOfClips; $++) { //DUDE ARRAY var dude:Array = frames; dude.y = yStart +11; dude.x = xVal +55; xVal = dude.x + dude.width + this.xOffset; } timer var timer:Timer = new Timer(100); timer.addEventListener(TimerEvent.TIMER, countdown); function countdown(event:TimerEvent) { var currentFrame:int = timer.currentCount % frames.length; for (var i:int = 0; i < frames.length; ++i) { frames[i].visible = (i == currentFrame); } } timer.start(); counter experiment My new class I'm working on loops through 10 different display objects that are numbers. For those following, I'm trying to make something like NumbersView.

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  • Django IntegrityError: foreign key violation upon delete

    - by Lukasz Korzybski
    I have Order and Shipment model. Shipment has a foreign key to Order. class Order(...): ... class Shipment() order = m.ForeignKey('Order') ... Now in one of my views I want do delete order object along with all related objects. So I invoke order.delete(). I have Django 1.0.4, PostgreSQL 8.4 and I use transaction middleware, so whole request is enclosed in single transaction. The problem is that upon order.delete() I get: ... File "/usr/local/lib/python2.6/dist-packages/django/db/backends/__init__.py", line 28, in _commit return self.connection.commit() IntegrityError: update or delete on table "main_order" violates foreign key constraint "main_shipment_order_id_fkey" on table "main_shipment" DETAIL: Key (id)=(45) is still referenced from table "main_shipment". I checked in connection.queries that proper queries are executed in proper order. First shipment is deleted, after that django executes delete on order row: {'time': '0.000', 'sql': 'DELETE FROM "main_shipment" WHERE "id" IN (17)'}, {'time': '0.000', 'sql': 'DELETE FROM "main_order" WHERE "id" IN (45)'} Foreign key have ON DELETE NO ACTION (default) and is initially deferred. I don't know why I get foreign key constraint violation. I also tried to register pre_delete signal and manually delete shipment objects before delete on order is called, but it resulted in the same error. I can change ON DELETE behaviour for this key in Postgres but it would be just a hack, I wonder if anyone has a better idea what's going on here. There is also a small detail, my Order model inherits from Cart model, so it actually doesn't have id field but cart_ptr_id and after DELETE on order is executed there is also DELETE on cart, but it seems unrelated? to the shipment-order problem so I simplified it in the example.

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  • How can I refactor this to work without breaking the pattern horribly?

    - by SnOrfus
    I've got a base class object that is used for filtering. It's a template method object that looks something like this. public class Filter { public void Process(User u, GeoRegion r, int countNeeded) { List<account> selected = this.Select(u, r, countNeeded); // 1 List<account> filtered = this.Filter(selected, u, r, countNeeded); // 2 if (filtered.Count > 0) { /* do businessy stuff */ } // 3 if (filtered.Count < countNeeded) this.SendToSuccessor(u, r, countNeeded - filtered) // 4 } } Select(...), Filter(...) are protected abstract methods and implemented by the derived classes. Select(...) finds objects in the based on x criteria, Filter(...) filters those selected further. If the remaining filtered collection has more than 1 object in it, we do some business stuff with it (unimportant to the problem here). SendToSuccessor(...) is called if there weren't enough objects found after filtering (it's a composite where the next class in succession will also be derived from Filter but have different filtering criteria) All has been ok, but now I'm building another set of filters, which I was going to subclass from this. The filters I'm building however would require different params and I don't want to just implement those methods and not use the params or just add to the param list the ones I need and have them not used in the existing filters. They still perform the same logical process though. I also don't want to complicated the consumer code for this (which looks like this) Filter f = new Filter1(); Filter f2 = new Filter2(); Filter f3 = new Filter3(); f.Sucessor = f2; f2.Sucessor = f3; /* and so on adding filters as successors to previous ones */ foreach (User u in users) { foreach (GeoRegion r in regions) { f.Process(u, r, ##); } } How should I go about it?

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  • Sync two SqlExpress using NHibernate

    - by Christian
    Hello, I am creating a simple project management system which uses NHibernate for object storage. The underlying database is SQL express (at least currently for development). The client runs on either the desktop or laptop. I know I could use web-services and store the DB only on the desktop, but this would force the desktop to be available all the time. I am currently thinking about duplicating the DB, having two instances with "different data". To clarify, we are not talking about a productive app here, its a prototype. One way to achieve this very simple would be the following process: Client: Check if desktop DB is available (through web service) Client: If yes, use desktop storage, no problem here Client: If not, use own DB as storage Client: Poll desktop regulary, as soon as it comes on, sync Client: Switch to desktop storage ... Desktop: Do not attempt any DB operation before checking for required sync Desktop: If sync needed, do it... My question is now, how would you sync? Assume 4 or 5 types of objects, all have GUID as identifiers. Would you always manually "lazy load" all objects of a certain type and feed them to the DB. Would you always drop the whole desktop DB in case the client DB may be newer and out of sync? Again, I want to stress out, I am not assuming any conflicts or stale data, I basically just want to "copy the whole DB from the client". Would you use NHibernate for this? Or would you separate the copy process? When I think about it, my questions comes down to this: Is there any function from NHibernate: SyncDBs_SourceWins_(SourceDB, TargetDB) Thanks for help, Chris

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  • How to filter Many2Many / Generic Relations properly with Q?

    - by HWM-Rocker
    Hi, I have 3 Models, the TaggedObject has a GenericRelation with the ObjectTagBridge. And the ObjectTagBridge has a ForeignKey to the Tag Model. class TaggedObject(models.Model): """ class that represent a tagged object """ tags = generic.GenericRelation('ObjectTagBridge', blank=True, null=True) class ObjectTagBridge(models.Model): """ Help to connect a generic object to a Tag. """ # pylint: disable-msg=W0232,R0903 content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') tag = models.ForeignKey('Tag') class Tag(models.Model): ... when I am attaching a Tag to an Object, I am creating a new ObjectTagBridge and set its ForeignKey tag to the Tag I want to attach. That is working fine, and I can get all Tags that I attached to my Object very easy. But when I want to get (filter) all Objects that have Tag1 and Tag2 I tried to something like this: query = Q(tags__tag=Tag1) & Q(tags__tag=Tag2) object_list = TaggedObjects.filter(query) but now my object_list is empty, because it is looking for TaggedObjects that have one ObjectTagBridge with 2 tag objects, the first with Tag1 and the second with Tag2. I my application will be more complex Q queries than this one, so I think I need a solution with this Q object. In fact any combination of binary conjunctions, like: (...) and ( (...) or not(...)) How can I filter this correctly? Every answer is welcome, maybe there is also a different way do achieve this. thx for your help!!!

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  • Getting Outlook calendar items based on subject

    - by EKS
    I'm trying to get a list of calendar objects from exchange and sorting them based on subject. The part of of getting the objects just based on date and sorting out via subject is in "code" is now working, but i want to do a sort on subject in the "sql" first, but im unable to make it work ( Currently getting error from exchange saying the query is wrong. The line I added is: + "AND lcase(\"urn:schemas:calendar:subject\") = 'onsite%' " What I want is the ability to catch all appointments that start with onsite, both in upper and lower case. strQuery = "<?xml version=\"1.0\"?>" + "<g:searchrequest xmlns:g=\"DAV:\">" + "<g:sql>SELECT \"urn:schemas:calendar:location\", \"urn:schemas:httpmail:subject\", " + "\"urn:schemas:calendar:dtstart\", \"urn:schemas:calendar:dtend\", " + "\"urn:schemas:calendar:busystatus\", \"urn:schemas:calendar:instancetype\" " + "FROM Scope('SHALLOW TRAVERSAL OF \"" + strCalendarURI + "\"') " + "WHERE NOT \"urn:schemas:calendar:instancetype\" = 1 " + "AND \"DAV:contentclass\" = 'urn:content-classes:appointment' " + "AND \"urn:schemas:calendar:dtstart\" > '2003/06/01 00:00:00' " //'" + DateString + "'" + "AND lcase(\"urn:schemas:calendar:subject\") = 'onsite' " + "ORDER BY \"urn:schemas:calendar:dtstart\" ASC" + "</g:sql></g:searchrequest>";

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  • Style first 2 TextViews in Android ListView differently

    - by Kurtis Nusbaum
    I have a ListView and I want the first two entries in it to be displayed differently than the rest. Nothing fancy, I want them all to just be text views. But the first two entries need to have different sizes and weights than the rest. I tried modifying the ArrayAdapter class like so: private class BusStopAdapter<T> extends ArrayAdapter<T>{ public BusStopAdapter( Context context, int textViewResourceId, List<T> objects) { super(context, textViewResourceId, objects); } public View getView(int position, View convertView, ViewGroup parent) { TextView toReturn = (TextView)super.getView(position, convertView, parent); if(position == 0){ toReturn.setTextSize(12); toReturn.setText("Previous Bus: " + toReturn.getText()); toReturn.setPadding(0,0,0,0); } else if(position == 1){ toReturn.setTextSize(20); toReturn.setPadding( toReturn.getPaddingLeft(), 0, toReturn.getPaddingRight(), 0 ); toReturn.setText("Next Bus: " + toReturn.getText()); toReturn.setGravity(Gravity.CENTER_HORIZONTAL|Gravity.TOP); } return toReturn; } } But this inadvertantly causes some of the other textviews to take on these special attributes. I think it's because cause textviews get "recycled" in the AbsListAdapter class.

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  • Should I invest in GraniteDS for Flex + Java development?

    - by Boden
    I'm new to Flex development, and RIAs in general. I've got a CRUD-style Java + Spring + Hibernate service on top of which I'm writing a Flex UI. Currently I'm using BlazeDS. This is an internal application running on a local network. It's become apparent to me that the way RIAs work is more similar to a desktop application than a web application in that we load up the entire model and work with it directly on the client (or at least the portion that we're interested in). This doesn't really jive well with BlazeDS because really it only supports remoting and not data management, thus it can become a lot of extra work to make sure that clients are in sync and to avoid reloading the model which can be large (especially since lazy loading is not possible). So it feels like what I'm left with is a situation where I have to treat my Flex application more like a regular old web application where I do a lot of fine grained loading of data. LiveCycle is too expensive. The free version of WebOrb for Java really only does remoting. Enter GraniteDS. As far as I can determine, it's the only free solution out there that has many of the data management features of LiveCycle. I've started to go through its documentation a bit and suddenly feel like it's yet another quagmire of framework that I'll have to learn just to get an application running. So my question(s) to the StackOverflow audience is: 1) do you recommend GraniteDS, especially if my current Java stack is Spring + Hibernate? 2) at what point do you feel like it starts to pay off? That is, at what level of application complexity do you feel that using GraniteDS really starts to make development that much better? In what ways?

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  • Static Variables somehow maintaining state?

    - by gfoley
    I am working on an existing project, setup by another coder. I'm having some trouble understanding how state is being maintained between pages. There is a Class library which has some helper objects. Mostly these objects are just used for there static methods and rarely instantiated or inherited. This is an example class I'm testing with. public sealed class Application { public static string Test; } Now when i run something like the following in the base class of my page, I would expect the result to be "1: 2:Test" all the time (note that "1" is empty), but strangly its only this way the first time it is run. Then every time afterwards its "1:Test 2:Test". Somehow its maintaining the state of the static variable between pages and being refreshed?? Response.Write("1:" + SharedLibrary.Application.Test); SharedLibrary.Application.Test = "Test"; Response.Write(" 2:" + SharedLibrary.Application.Test); I need to create more classes like this, but want to understand why this is occurring in the first place. Many Thanks

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  • How to provide an inline model field with a queryset choices without losing field value for inline r

    - by Judith Boonstra
    The code displayed below is providing the choices I need for the app field, and the choices I need for the attr field when using Admin. I am having a problem with the attr field on the inline form for already saved records. The attr selected for these saved does show in small print above the field, but not within the field itself. # MODELS: Class Vocab(models.Model): entity = models.Charfield, max_length = 40, unique = True) Class App(models.Model): name = models.ForeignKey(Vocab, related_name = 'vocab_appname', unique = True) app = SelfForeignKey('self, verbose_name = 'parent', blank = True, null = True) attr = models.ManyToManyField(Vocab, related_name = 'vocab_appattr', through ='AppAttr' def parqs(self): a method that provides a queryset consisting of available apps from vocab, excluding self and any apps within the current app's dependent line. def attrqs(self): a method that provides a queryset consisting of available attr from vocab excluding those already selected by current app, 2) those already selected by any apps within the current app's parent line, and 3) those selected by any apps within the current app's dependent line. Class AppAttr(models.Model): app = models.ForeignKey(App) attr = models.ForeignKey(Vocab) # FORMS: from models import AppAttr def appattr_form_callback(instance, field, *args, **kwargs) if field.name = 'attr': if instance: return field.formfield(queryset = instance.attrqs(), *kwargs) return field.formfield(*kwargs) # ADMIN: necessary imports class AppAttrInline(admin.TabularInline): model = AppAttr def get_formset(self, request, obj = None, **kwargs): kwargs['formfield_callback'] = curry(appattr_form_callback, obj) return super(AppAttrInline, self).get_formset(request, obj, **kwargs) class AppForm(forms.ModelForm): class Meta: model = App def __init__(self, *args, **kwargs): super(AppForm, self).__init__(*args, **kwargs) if self.instance.id is None: working = App.objects.all() else: thisrec = App.objects.get(id = self.instance.id) working = thisrec.parqs() self.fields['par'].queryset = working class AppAdmin(admin.ModelAdmin): form = AppForm inlines = [AppAttrInline,] fieldsets = .......... necessary register statements

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  • Are there any downsides in using C++ for network daemons?

    - by badcat
    Hey guys! I've been writing a number of network daemons in different languages over the past years, and now I'm about to start a new project which requires a new custom implementation of a properitary network protocol. The said protocol is pretty simple - some basic JSON formatted messages which are transmitted in some basic frame wrapping to have clients know that a message arrived completely and is ready to be parsed. The daemon will need to handle a number of connections (about 200 at the same time) and do some management of them and pass messages along, like in a chat room. In the past I've been using mostly C++ to write my daemons. Often with the Qt4 framework (the network parts, not the GUI parts!), because that's what I also used for the rest of the projects and it was simple to do and very portable. This usually worked just fine, and I didn't have much trouble. Being a Linux administrator for a good while now, I noticed that most of the network daemons in the wild are written in plain C (of course some are written in other languages, too, but I get the feeling that 80% of the daemons are written in plain C). Now I wonder why that is. Is this due to a pure historic UNIX background (like KISS) or for plain portability or reduction of bloat? What are the reasons to not use C++ or any "higher level" languages for things like daemons? Thanks in advance! Update 1: For me using C++ usually is more convenient because of the fact that I have objects which have getter and setter methods and such. Plain C's "context" objects can be a real pain at some point - especially when you are used to object oriented programming. Yes, I'm aware that C++ is a superset of C, and that C code is basically C++. But that's not the point. ;)

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  • Sending a JSON object to an ASP.NET web service using JQUERY ajax function

    - by uzay95
    I want to create object on the client side of aspx page. And i want to add functions to these javascript classes to make easier the life. Actually i can get and use the objects (derived from the server side classes) which returns from the services. When i wanted to send objects from the client by jquery ajax methods, i couldn't do it :) This is my javascript object: function ClassAndMark(_mark, _lesson){ this.Lesson = _lesson; this.Mark = _mark; } function Student(_name, _surname, _classAndMark){ this.Name = _name; this.SurName = _surname; this.ClassAndMark = _classAndMark; } JSClass.prototype.fSaveToDB(){ $.ajax({ type: "POST", contentType: "application/json; charset=utf-8", url: "/WS/SaveObject.asmx/fSaveToDB"), data: ????????????, dataType: "json" }); } Actually i don't know what should be definition of classes and methods on the Server side but i think: class ClassAndMark{ public string Lesson ; public string Mark ; } class Student{ public string Name ; public string SurName ; public ClassAndMark ClassAndMark ; } Web service is below but again i couldn't get what should be instead of the ???? : [WebMethod()] public void fSaveToDB(???? _obj) { // How can i convert input parameter/parameters // of method in the server side object? }

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  • Android: CustomListAdapter

    - by primal
    Hi, I have implemented a custom list view which looks like the twitter timeline. adapter = new MyClickableListAdapter(this, R.layout.timeline, mObjectList); setListAdapter(adapter); The constructor for MyClickableListAdapter is as follows private class MyClickableListAdapter extends ClickableListAdapter{ public MyClickableListAdapter(Context context, int viewId, List objects) { super(context, viewId, objects); } ClickableListAdapter extends BaseAdapter and implements the necessary methods. The xml code for the list view is as follows <ListView android:id="@+id/android:list" android:layout_width="fill_parent" android:layout_height="wrap_content" /> This is what it looks like. I have 3 questions 1) I tried registering a context menu for the list view by adding the line after setting the list adapter registerforContextMenu(getListView()); But on long-click the menu doesnt get displayed. I cannot understand what I am doing wrong! 2) Is it possible to display a textview above the listview? I tried it by adding the code for textview above the listview. But then, only the textview gets displayed. 3) I have seen in many twitter clients that on clicking post a window pops up from the top covering only some portion of the screen and rest of the timeline is visible. How can this be done possibly without starting a new activity? Any help would be much appreciated..

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  • python os.mkfifo() for Windows

    - by user302099
    Hello. Short version (if you can answer the short version it does the job for me, the rest is mainly for the benefit of other people with a similar task): In python in Windows, I want to create 2 file objects, attached to the same file (it doesn't have to be an actual file on the hard-drive), one for reading and one for writing, such that if the reading end tries to read it will never get EOF (it will just block until something is written). I think in linux os.mkfifo() would do the job, but in Windows it doesn't exist. What can be done? (I must use file-objects). Some extra details: I have a python module (not written by me) that plays a certain game through stdin and stdout (using raw_input() and print). I also have a Windows executable playing the same game, through stdin and stdout as well. I want to make them play one against the other, and log all their communication. Here's the code I can write (the get_fifo() function is not implemented, because that's what I don't know to do it Windows): class Pusher(Thread): def __init__(self, source, dest, p1, name): Thread.__init__(self) self.source = source self.dest = dest self.name = name self.p1 = p1 def run(self): while (self.p1.poll()==None) and\ (not self.source.closed) and (not self.source.closed): line = self.source.readline() logging.info('%s: %s' % (self.name, line[:-1])) self.dest.write(line) self.dest.flush() exe_to_pythonmodule_reader, exe_to_pythonmodule_writer =\ get_fifo() pythonmodule_to_exe_reader, pythonmodule_to_exe_writer =\ get_fifo() p1 = subprocess.Popen(exe, shell=False, stdin=subprocess.PIPE, stdout=subprocess.PIPE) old_stdin = sys.stdin old_stdout = sys.stdout sys.stdin = exe_to_pythonmodule_reader sys.stdout = pythonmodule_to_exe_writer push1 = Pusher(p1.stdout, exe_to_pythonmodule_writer, p1, '1') push2 = Pusher(pythonmodule_to_exe_reader, p1.stdin, p1, '2') push1.start() push2.start() ret = pythonmodule.play() sys.stdin = old_stdin sys.stdout = old_stdout

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  • How to maintain a persistant network-connection between two applications over a network?

    - by John
    I was recently approached by my management with an interesting problem - where I am pretty sure I am telling my bosses the correct information but I really want to make sure I am telling them the correct stuff. I am being asked to develop some software that has this function: An application at one location is constantly processing real-time data every second and only generates data if the underlying data has changed in any way. On the event that the data has changed send the results to another box over a network Maintains a persistent connection between the both machines, altering the remote box if for some reason the network connection went down From what I understand, I imagine that I need to do some reading on doing some sort of TCP/IP socket-level stuff. That way if the connection is dropped the remote location will be aware that the data it has received may be stale. However management seems to be very convinced that this can be accomplished using SOAP. I was under the impression that SOAP is more or less a way for a client to initiate a procedure from a server and get some results via the HTTP protocol. Am I wrong in assuming this? I haven't been able to find much information on how SOAP might be able to solve a problem like this. I feel like a lot of people around my office are using SOAP as a buzzword and that has generated a bit of confusion over what SOAP actually is - and is capable of. Any thoughts on how to accomplish this task would be appreciated!

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  • What's the difference between DI and factory patterns?

    - by Anthony Short
    I have a class which depends on 3 classes, all 3 of which have other classes they rely on. Currently, I'm using a container class to build up all the required classes, inject them into one another and return the application. The simplified version of the container looks something like this: class Builder { private $_options; public function __construct($options) { $this->_options = $options; } public function build() { $cache = $this->getCache(); $response = $this->getResponse(); $engine = $this->getEngine(); return new Application($cache,$response,$engine); } public function getResponse() { $encoder = $this->getResponseEncoder(); $cache = $this->getResponseCache(); return new Response($encoder,$cache); } // Methods for building each object } I'm not sure if this would be classified as FactoryMethod or a DI Container. They both seem to solve the same problem in the same way - They build objects and inject dependencies. This container has some more complicated building methods, like loading observers and attaching them to observable objects. Should factories be doing all the building (loading extensions etc) and the DI container should use these factories to inject dependencies? That way the sub-packages, like Cache, Response etc, can each have their own specialised factories.

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  • Multithreaded linked list traversal

    - by Rob Bryce
    Given a (doubly) linked list of objects (C++), I have an operation that I would like multithread, to perform on each object. The cost of the operation is not uniform for each object. The linked list is the preferred storage for this set of objects for a variety of reasons. The 1st element in each object is the pointer to the next object; the 2nd element is the previous object in the list. I have solved the problem by building an array of nodes, and applying OpenMP. This gave decent performance. I then switched to my own threading routines (based off Windows primitives) and by using InterlockedIncrement() (acting on the index into the array), I can achieve higher overall CPU utilization and faster through-put. Essentially, the threads work by "leap-frog'ing" along the elements. My next approach to optimization is to try to eliminate creating/reusing the array of elements in my linked list. However, I'd like to continue with this "leap-frog" approach and somehow use some nonexistent routine that could be called "InterlockedCompareDereference" - to atomically compare against NULL (end of list) and conditionally dereference & store, returning the dereferenced value. I don't think InterlockedCompareExchangePointer() will work since I cannot atomically dereference the pointer and call this Interlocked() method. I've done some reading and others are suggesting critical sections or spin-locks. Critical sections seem heavy-weight here. I'm tempted to try spin-locks but I thought I'd first pose the question here and ask what other people are doing. I'm not convinced that the InterlockedCompareExchangePointer() method itself could be used like a spin-lock. Then one also has to consider acquire/release/fence semantics... Ideas? Thanks!

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  • Questions regarding detouring by modifying the virtual table

    - by Elliott Darfink
    I've been practicing detours using the same approach as Microsoft Detours (replace the first five bytes with a jmp and an address). More recently I've been reading about detouring by modifying the virtual table. I would appreciate if someone could shed some light on the subject by mentioning a few pros and cons with this method compared to the one previously mentioned! I'd also like to ask about patched vtables and objects on the stack. Consider the following situation: // Class definition struct Foo { virtual void Call(void) { std::cout << "FooCall\n"; } }; // If it's GCC, 'this' is passed as the first parameter void MyCall(Foo * object) { std::cout << "MyCall\n"; } // In some function Foo * foo = new Foo; // Allocated on the heap Foo foo2; // Created on the stack // Arguments: void ** vtable, uint offset, void * replacement PatchVTable(*reinterpret_cast<void***>(foo), 0, MyCall); // Call the methods foo->Call(); // Outputs: 'MyCall' foo2.Call(); // Outputs: 'FooCall' In this case foo->Call() would end up calling MyCall(Foo * object) whilst foo2.Call() call the original function (i.e Foo::Call(void) method). This is because the compiler will try to decide any virtual calls during compile time if possible (correct me if I'm wrong). Does that mean it does not matter if you patch the virtual table or not, as long as you use objects on the stack (not heap allocated)?

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  • Django: Determining if a user has voted or not

    - by TheLizardKing
    I have a long list of links that I spit out using the below code, total votes, submitted by, the usual stuff but I am not 100% on how to determine if the currently logged in user has voted on a link or not. I know how to do this from within my view but do I need to alter my below view code or can I make use of the way templates work to determine it? I have read http://stackoverflow.com/questions/1528583/django-vote-up-down-method but I don't quite understand what's going on ( and don't need any ofjavascriptery). Models (snippet): class Link(models.Model): category = models.ForeignKey(Category, blank=False, default=1) user = models.ForeignKey(User) created = models.DateTimeField(auto_now_add=True) modified = models.DateTimeField(auto_now=True) url = models.URLField(max_length=1024, unique=True, verify_exists=True) name = models.CharField(max_length=512) def __unicode__(self): return u'%s (%s)' % (self.name, self.url) class Vote(models.Model): link = models.ForeignKey(Link) user = models.ForeignKey(User) created = models.DateTimeField(auto_now_add=True) def __unicode__(self): return u'%s vote for %s' % (self.user, self.link) Views (snippet): def hot(request): links = Link.objects.select_related().annotate(votes=Count('vote')).order_by('-created') for link in links: delta_in_hours = (int(datetime.now().strftime("%s")) - int(link.created.strftime("%s"))) / 3600 link.popularity = ((link.votes - 1) / (delta_in_hours + 2)**1.5) if request.user.is_authenticated(): try: link.voted = Vote.objects.get(link=link, user=request.user) except Vote.DoesNotExist: link.voted = None links = sorted(links, key=lambda x: x.popularity, reverse=True) links = paginate(request, links, 15) return direct_to_template( request, template = 'links/link_list.html', extra_context = { 'links': links, }) The above view actually accomplishes what I need but in what I believe to be a horribly inefficient way. This causes the dreaded n+1 queries, as it stands that's 33 queries for a page containing just 29 links while originally I got away with just 4 queries. I would really prefer to do this using Django's ORM or at least .extra(). Any advice?

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  • c++ struct size

    - by kiokko89
    struct CExample { int a; } int main(int argc, char* argv[]) { CExample ce; CExample ce2; cout << "Size:" << sizeof(ce)<< " Address: "<< &ce<< endl; cout << "Size:" << sizeof(ce2)<< " Address: "<< &ce2 << endl; CExample ceArr[2]; cout << "Size:" << sizeof(ceArr[0])<< " Address: "<<&ceArr[0]<<endl; cout << "Size:" << sizeof(ceArr[1])<< " Address: "<<&ceArr[1]<<endl; return 0; } Excuse me I'm just a beginner but i'd like to know why with this code, there is a difference of 12 bytes between the addresses of the first two objects(ce and ce2) (i thought about data allignment), but there is only a difference of 4 bytes between the two objects in the array. Sorry for my bad English...

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  • Attribute Address getting displayed instead of Attribute Value

    - by Manish
    I am try to create the following. I want to have one drop down menu. Depending on the option selected in the first drop down menu, options in second drop down menu will be displayed. The options in 2nd drop down menu is supposed by dynamic, i.e., options change with the change of values in first menu. Here, instead of getting the drop down menus, I am getting the following Choose your Option1: Choose your Option2: Note: I strictly don't want to use javascript. home_form.py class HomeForm(forms.Form): def __init__(self, *args, **kwargs): var_filter_con = kwargs.pop('filter_con', None) super(HomeForm, self).__init__(*args, **kwargs) if var_filter_con == '***': var_empty_label = None else: var_empty_label = ' ' self.option2 = forms.ModelChoiceField(queryset = db_option2.objects.filter(option1_id = var_filter_con).order_by("name"), empty_label = var_empty_label, widget = forms.Select(attrs={"onChange":'this.form.submit();'}) ) self.option1 = forms.ModelChoiceField(queryset = db_option1.objects.all().order_by("name"), empty_label=None, widget=forms.Select(attrs={"onChange":'this.form.submit();'}) ) view.py def option_view(request): if request.method == 'POST': form = HomeForm(request.POST) if form.is_valid(): cd = form.cleaned_data if cd.has_key('option1'): f = HomeForm(filter_con = cd.get('option1')) return render_to_response('homepage.html', {'home_form':f,}, context_instance=RequestContext(request)) return render_to_response('invalid_data.html', {'form':form,}, context_instance=RequestContext(request)) else: f = HomeForm(filter_con = '***') return render_to_response('homepage.html', {'home_form':f,}, context_instance=RequestContext(request)) homepage.html <!DOCTYPE HTML> <head> <title>Nivaaran</title> </head> <body> <form method="post" name = 'choose_opt' action=""> {% csrf_token %} Choose your Option1: {{ home_form.option1 }} <br/> Choose your Option2: {{ home_form.option2 }} </form> </body>

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  • Sharing same properties of ViewController for iPhone Stroryboard and iPad Story Board

    - by Ruhul Amin
    I'm developing a universal application. in the first view, I have the login screen for the user. In iPhone storyBoard, I have added 2 text field and one button( login check). I have added properties in ViewController.h file by dragging those objects(Ctrl key + Dragg) to .h file. I have added code for login check and it is working fine for iPhone. This is the code in ViewController.h @property (strong, nonatomic) IBOutlet UITextField *txtUserId; @property (strong, nonatomic) IBOutlet UITextField *txtUserPwd; @property (strong, nonatomic) IBOutlet UIButton *btnLogin; In the iPad storyBoard, I have added 2 text field( userid and password) and i button for login. So now, I want to bind those objects with the veriable which I declared already in ViewController.h file in case of iPhone. My questions: 1. What is the right way to bind properties for both storyboard? 2. Am I on the right direction or should I think in a different way to do it? I am new with iPhone development. Please help. Thanks. --Amin

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  • Java/Hibernate using interfaces over the entities.

    - by Dennetik
    I am using annoted Hibernate, and I'm wondering whether the following is possible. I have to set up a series of interfaces representing the objects that can be persisted, and an interface for the main database class containing several operations for persisting these objects (... an API for the database). Below that, I have to implement these interfaces, and persist them with Hibernate. So I'll have, for example: public interface Data { public String getSomeString(); public void setSomeString(String someString); } @Entity public class HbnData implements Data, Serializable { @Column(name = "some_string") private String someString; public String getSomeString() { return this.someString; } public void setSomeString(String someString) { this.someString = someString; } } Now, this works fine, sort of. The trouble comes when I want nested entities. The interface of what I'd want is easy enough: public interface HasData { public Data getSomeData(); public void setSomeData(Data someData); } But when I implement the class, I can follow the interface, as below, and get an error from Hibernate saying it doesn't know the class "Data". @Entity public class HbnHasData implements HasData, Serializable { @OneToOne(cascade = CascadeType.ALL) private Data someData; public Data getSomeData() { return this.someData; } public void setSomeData(Data someData) { this.someData = someData; } } The simple change would be to change the type from "Data" to "HbnData", but that would obviously break the interface implementation, and thus make the abstraction impossible. Can anyone explain to me how to implement this in a way that it will work with Hibernate?

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  • Sending information between JavaScript and Web Services using AJAX

    - by COB-CSU-AM
    Alright so I'm using Microsoft's Web Services and AJAX to get information from a SQL database for use with java script on the client side. And I'm wondering what the best method is. Before I started working on the project, the web services were setup to return a C# List filled with some objects. Those objects variables (ints, strings, etc.) contain the data I want to use. Of course, java script can't do much with this, to the best of my knowledge. I then modified the web service to return a 2D Array, but java script got confused, and to the best of my knowledge can't handle 2D array's returned from C#. I then tried to use a regular array, but then a found the length property of an array in JS doesn't carry over, so I couldn't preform a for loop through all the items, because there wasn't anyway of knowing how many elements there were. The only other thing I can thing of is returning a string with special char's to separate the data, but this seems way too convoluted. Any suggestions? Thanks in advance!

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