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• Does implementing a Java class under an open-source library's package name constitutes a modificatio

  - by Minyu

  Greetings, I understand that this is not the best forum for getting legal advices. But I am still wondering if anybody has some experience around this topic, or can point me to relevant resources that explain it. I have tried to search it online but could not find clear answers. Assuming I am using a Java open-source library from "somecompany", specifically its entities in the "org.somecompany.somepackage". During development, I found that I need to access some of the internals of that package that are not exposed through its public interface. So I thought maybe creating my own classes under the same "org.somecompany.somepackage" name would make that easier. My question is: does this constitutes a modification of the open-source library? The fully qualified name of my classes look like "org.somecompany.somepackage.myclass". It does seem an "extension" of the original library, even though I am not modifying the original library source or binary. I am also not adding my classes to the open-source jar files. Any advice or pointer to resources will be appreciated!

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• .net web service annoying issue

  - by JL

  Excuse the title, but it's best I just explain the problem. I have 2 projects in my solution A Class Library A Web Application, which consists of a web service (asmx). the web service has code sitting in the app_code folder, with a file [webservicename].cs Inside the webservice code behind class, I have a web method here is a sample example (its simplified): [WebMethod] public EnumTaskExportState ProcessTask() { var tm = new UploadTaskManager(); return tm.ProcessTask(); } Now at design time, in visual studio (2010 or 2008), when I right click on UploadTaskMananger, and then select "Go to definition". I get taken to AppData\Temp[some folder structure]...etc.... and it displays the public class definition. Instead I would like to have complete integration, so that I get taken directly to the actual class in the class library project. My guess is, this is happening because I am using the app_code route, and not a compiled file for the web service class. But I don't know any other way to do this. How can I fix this? Possibly do away with the need for the app_code directory?

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• Mongodb, linq driver. How to construct Contains with variable or statements

  - by Syska

  I'm using the LINQ Driver for C#, works great. Sorting a lot of properties but heres a problem I can't solve, its probebly simple. var identifierList = new []{"10", "20", "30"}; var newList = list.Where(x => identifierList.Contains(x.Identifier)); This is NOT supported ... So I could do something like: var newList = list.Where(x => x.Identifier == "10" || x.Identifier == "20" || x.Identifier == "30"); But since the list is variable ... how do I construct the above? Or are there even better alternatives? The list is of type IQueryable<MyCustomClass> For information ... this is used as a filter of alot of properties. In SQL I could have a parent - child relationship. But as I can't as the parent for the main ID I need to take all the ID's out and then construct it like this. Hopes this makes sense. If needed I will explain more.

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• How can this Ambient Context become null?

  - by Mark Seemann

  Can anyone help me explain how TimeProvider.Current can become null in the following class? public abstract class TimeProvider { private static TimeProvider current = DefaultTimeProvider.Instance; public static TimeProvider Current { get { return TimeProvider.current; } set { if (value == null) { throw new ArgumentNullException("value"); } TimeProvider.current = value; } } public abstract DateTime UtcNow { get; } public static void ResetToDefault() { TimeProvider.current = DefaultTimeProvider.Instance; } } Observations All unit tests that directly reference TimeProvider also invokes ResetToDefault() in their Fixture Teardown. There is no multithreaded code involved. Once in a while, one of the unit tests fail because TimeProvider.Current is null (NullReferenceException is thrown). This only happens when I run the entire suite, but not when I just run a single unit test, suggesting to me that there is some subtle test interdependence going on. It happens approximately once every five or six test runs. When a failure occurs, it seems to be occuring in the first executed tests that involves TimeProvider.Current. More than one test can fail, but only one fails in a given test run. FWIW, here's the DefaultTimeProvider class as well: public class DefaultTimeProvider : TimeProvider { private readonly static DefaultTimeProvider instance = new DefaultTimeProvider(); private DefaultTimeProvider() { } public override DateTime UtcNow { get { return DateTime.UtcNow; } } public static DefaultTimeProvider Instance { get { return DefaultTimeProvider.instance; } } } I suspect that there's some subtle interplay going on with static initialization where the runtime is actually allowed to access TimeProvider.Current before all static initialization has finished, but I can't quite put my finger on it. Any help is appreciated.

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• issue with tab bar view displaying a compound view

  - by ambertch

  I created a tab bar application, and I make the first tab a table. So I create a tableView controller, and go about setting the class identity of the view controller for the first tab to my tableView controller. This works fine, and I see the contents of the table filling up the whole screen. However, this is not what I actually want in the end goal - I would like a compound window having multiple views: - the aforementioned table - a custom view with data in it So what I do is create a nib for this content (call it contentNib), change the tab's class from the tableView controller to a generic UIViewController, and set the nib of that tab to this new contentNib. In this new contentNib I drag on a tableView and set File's Owner to the TableViewController. I then link the dataSource and delegate to file's owner (which is TableViewController). Surprisingly this does not work and I receive the error: **Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[UIViewController tableView:numberOfRowsInSection:]: unrecognized selector sent to instance 0x3b0f910'** This is bewildering to me since the file's owner is the TableViewController, which has been assigned to be both the dataSource and delegate. Does someone have either insight into my confusions, or a link to an example of how to have a compound view include a tableView? *update* I see this in the Apple TableView programming guide: "Note: You should use a UIViewController subclass rather than a subclass of UITableViewController to manage a table view if the view to be managed is composed of multiple subviews, one of which is a table view. The default behavior of the UITableViewController class is to make the table view fill the screen between the navigation bar and the tab bar (if either are present)." <----- I don't really get what this is telling me to do though... if someone can explain or point me to an example I'd be much appreciated!

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• How do I select column(s) by their "numeric" position in a table?

  - by DulcimerDude

  I am trying to select columns by their "x" position in the table. DBI my $example = $hookup->prepare(qq{SELECT This,That,Condition,"I also want COLUMN-10" FROM tbl LIMIT ? ?}); ###column_number=10 ordinal_position?? $example->execute('2','10') or die "Did not execute"; Is this possible or do I need to run another single select to just that column? One problem I encountered was with a col named "Condition". For some reason, when I tried to select Condition the execute would die. I never attempted but, What if the column name was SELECT? Another note is the table is 75 cols wide and I only need 50 of them. The Col names are pretty verbose so, I would like to just call them by their "position". This would also allow the col names to be changed in the future without having to change the select statement. I am quite the newbie so please explain any answers down to my level. Thanks for any assistance..

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• Celery Received unregistered task of type (run example)

  - by Echeg

  I'm trying to run example from Celery documentation. I run: celeryd --loglevel=INFO /usr/local/lib/python2.7/dist-packages/celery/loaders/default.py:64: NotConfigured: No 'celeryconfig' module found! Please make sure it exists and is available to Python. "is available to Python." % (configname, ))) [2012-03-19 04:26:34,899: WARNING/MainProcess] -------------- celery@ubuntu v2.5.1 ---- **** ----- --- * *** * -- [Configuration] -- * - **** --- . broker: amqp://guest@localhost:5672// - ** ---------- . loader: celery.loaders.default.Loader - ** ---------- . logfile: [stderr]@INFO - ** ---------- . concurrency: 4 - ** ---------- . events: OFF - *** --- * --- . beat: OFF -- ******* ---- --- ***** ----- [Queues] -------------- . celery: exchange:celery (direct) binding:celery tasks.py: # -*- coding: utf-8 -*- from celery.task import task @task def add(x, y): return x + y run_task.py: # -*- coding: utf-8 -*- from tasks import add result = add.delay(4, 4) print (result) print (result.ready()) print (result.get()) In same folder celeryconfig.py: CELERY_IMPORTS = ("tasks", ) CELERY_RESULT_BACKEND = "amqp" BROKER_URL = "amqp://guest:guest@localhost:5672//" CELERY_TASK_RESULT_EXPIRES = 300 When I run "run_task.py": on python console eb503f77-b5fc-44e2-ac0b-91ce6ddbf153 False errors on celeryd server [2012-03-19 04:34:14,913: ERROR/MainProcess] Received unregistered task of type 'tasks.add'. The message has been ignored and discarded. Did you remember to import the module containing this task? Or maybe you are using relative imports? Please see http://bit.ly/gLye1c for more information. The full contents of the message body was: {'retries': 0, 'task': 'tasks.add', 'utc': False, 'args': (4, 4), 'expires': None, 'eta': None, 'kwargs': {}, 'id': '841bc21f-8124-436b-92f1-e3b62cafdfe7'} Traceback (most recent call last): File "/usr/local/lib/python2.7/dist-packages/celery/worker/consumer.py", line 444, in receive_message self.strategies[name](message, body, message.ack_log_error) KeyError: 'tasks.add' Please explain what's the problem.

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• Invoking jQuery function without an element

  - by Sandman

  So, I use jQuery quite extensively and I am well aware of the "right" way to do the below, but there are times where I want to solve it in a more generic way. I'll explain. So, I may have a link, like this: <a href='menu' class='popup'>Show menu</a>. Now, I have a jQuery function that fires on click for all a.popup that takes the href-attribute and shows the <div id='menu'></div> item (in this case). It also handles URL's if it can't find a DOM item with that ID. No problem here. But, there are times when I don't have the same control over the coe where I can create a selectable target that way. Either because the code isn't created by me or because it is created through a chain of function that would all need a huge ovrhaul which I won't do. So, from time to time, I would like to have this code: <a href="javascript:popup('menu')">Show menu</a> This would be in a case where I can only submit the label and the HREF for a link. No class, no nothing. Problem here is that the function popup() has no idea about what element invoked it, and in most cases that's not a problem for me, since I only need to know where the mouse cursor was upon invokation. But in some cases, I use someone elses jQuery functions, like qTip or something else. so I still want to fire off qTip(); when clicking a link that runs this JS function, but what do I attach it to to make it show? I can't just runt $().qTip(); because that implies $(this) and "this" is undefined inside the function. So how do I do it? Any ideas?

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• How to strongly type properties in JavaScript that map to models in C# ?

  - by Roberto Sebestyen

  I'm not even sure if I worded the question right, but I'll try and explain as clearly as possible with an example: In the following example scenario: 1) Take a class such as this: public class foo { public string firstName {get;set;} public string lastName {get;set} } 2) Serialize that into JSON, pass it over the wire to the Browser. 3) Browser de-serializes this and turns the JSON into a JavaScript object so that you can then access the properties like this: var foo = deSerialize("*******the JSON from above**************"); alert(foo.firstName); alert(foo.lastName); What if now a new developer comes along working on this project decides that firstName is no longer a suitable property name. Lets say they use ReSharper to rename this property, since ReSharper does a pretty good job at finding (almost) all the references to the property and renaming them appropriately. However ReSharper will not be able to rename the references within the JavaScript code (#3) since it has no way of knowing that these also really mean the same thing. Which means the programmer is left with the responsibility of manually finding these references and renaming those too. The risk is that if this is forgotten, no one will know about this error until someone tests that part of the code, or worse, slip through to the customer. Back to the actual question: I have been trying to think of a solution to this to some how strongly type these property names when used in javascript, so that a tool like ReSharper can successfully rename ALL usages of the property? Here is what I have been thinking for example (This would obviously not work unless i make some kind of static properties) var foo = deSerialize("*******the JSON from above**************"); alert(foo.<%=foo.firstName.GetPropertyName()%>) alert(foo.<%=foo.lastName.GetPropertyName()%>) But that is obviously not practical. Does anyone have any thoughts on this? Thanks, and kudos to all of the talented people answering questions on this site.

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• QProgressBar problem with uploading

  - by rolanddd

  Hey all! I show my code first, then I explain my problem: ... // somewhere in the constructor progressBar = new QProgressBar(this); progressBar-setMinimum(0); progressBar-setMaximum(100); ... connect(&http, SIGNAL(dataSendProgress(int, int)), this, SLOT(updateProgressBar(int, int))); ... void MainWindow::updateProgressBar(int bytesSent, int total) { progressBar-setMaximum(total); progressBar-setValue(bytesSent); } So this is how I try to make my progressBar being updated when I upload a file. The problem is, it won't do the job. When it starts uploading, I set the value of the progress bar to 0, then (thanks to this slot) it won't actually show the progress, but will jump to 100% immediately (even before it finished uploading). I already checked the HTTP Client example, and copied the progress bar part, it is for downloading, and more or less is the same as for uploading but it uses the dataReadProgress signal (needed for downloading) AND it works perfectly. Does anybody know how to solve this for uploading?

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• Div's are not filtered as :hidden when display:none; is appended as style

  - by CodeMonkey

  Hey folks I have some simple HTML: <div id="selectorContainer"> <div id="chainedSelector" style="display: none;"><% Html.RenderPartial("ProjectSuggest/ChainedProjectSelector"); %></div> <div id="suggestSelector"><% Html.RenderPartial("ProjectSuggest/SuggestControl", new SuggestModeDTO{RegistrationMode = Model.RegistrationMode}); %></div> </div> which is two containers for controls. I have jQuery code to toggle between displaying these, but I need to store as a cookie which one was used last time the user was logged in (i.e. which one was visible). The storing of the cookie is not the problem. The problem is that I for some reason am not able to detect which one is the hidden one, using .is(":hidden"), and not able to detect which one is visible using .is(":visible") When I use those two selectors, I always get both. "true" and "true" for both, eventhough one has display: none; and the other doesn't. Please note that they are NOT placed inside a hidden container which otherwise would hide both, so there are not any hidden ancestor containers. Can anyone maybe explain why this could happen? jQuery code containing source for getting the Id's and for getting the selected one (which currently is broken): getChainedSelectorId: function() { return "#chainedSelector"; }, getSuggestSelectorId: function() { return "#suggestSelector"; }, getSelectedSelector: function() { alert($(this.getChainedSelectorId()).is(":hidden")); alert($(this.getSuggestSelectorId()).is(":hidden")); var selected = ($(this.getChainedSelectorId()).is(":visible") ? this.getChainedSelectorId() : this.getSuggestSelectorId()); alert(selected); return selected; }, Thanks in advance.

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• What is the worst gotcha in WPF?

  - by David

  Hi, I've started to make myself a list of "WPF gotchas": things that bug me and that I had to write down to remember because I fall for them every time.... Now, I'm pretty sure you all stumbled upon similar situations at one point, and I would like you to share your experience on the subject: What is the gotcha that gets you all the time? the one you find the most annoying? (I have a few issues that seem to be without explanation, maybe your submissions will explain them) Here are a few of my "personnal" gotchas (randomly presented): For a MouseEvent to be fired even when the click is on the "transparent" background of a control (e.g. a label) and not just on the content (the Text in this case), the control's Background has to be set to "Brushes.Transparent" and not just "null" (default value for a label) A WPF DataGridCell's DataContext is the RowView to whom the cell belong, not the CellView When inside a ScrollViewer, a Scrollbar is managed by the scrollviewer itself (i.e. setting properties such as ScrollBar.Value is without effect) Key.F10 is not fired when you press "F10", instead you get Key.System and you have to go look for e.SystemKey to get the Key.F10 ... and now you're on.

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• opengl: question about glutMainLoop()

  - by lego69

  can somebody explain how does glutMainLoop work? and second question, why glClearColor(0.0f, 0.0f, 1.0f, 1.0f); defined after glutDisplayFunc(RenderScene); cause firstly we call glClear(GL_COLOR_BUFFER_BIT); and only then define glClearColor(0.0f, 0.0f, 1.0f, 1.0f); int main(int argc, char* argv[]) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(800, 00); glutInitWindowPosition(300,50); glutCreateWindow("GLRect"); glutDisplayFunc(RenderScene); glutReshapeFunc(ChangeSize); glClearColor(0.0f, 0.0f, 1.0f, 1.0f); <-- glutMainLoop(); return 0; } void RenderScene(void) { // Clear the window with current clearing color glClear(GL_COLOR_BUFFER_BIT); // Set current drawing color to red // R G B glColor3f(1.0f, 0.0f, 1.0f); // Draw a filled rectangle with current color glRectf(0.0f, 0.0f, 50.0f, -50.0f); // Flush drawing commands glFlush(); }

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• Installing Image_Graph and using with BASE

  - by PPowerHouseK

  Hello all, I have Windows 7 with the latest XAMPP installation. I configured BASE to work, for the most part. My problem is that in BASE, when I click on the graph alerts button, I get this error: Error loading the Graphing library: Check your Pear::Image_Graph installation! * Image_Graph can be found here:at http://pear.veggerby.dk/. Without this library no graphing operations can be performed. * Make sure PEAR libraries can be found by php at all: pear config-show | grep "PEAR directory" PEAR directory php_dir /usr/share/pear This path must be part of the include path of php (cf. /etc/php.ini): php -i | grep "include_path" include_path => .:/usr/share/pear:/usr/share/php => .:/usr/share/pear:/usr/share/php</code> I think it may have to do with the include path of the php.ini so here is what it currently says: ;;;;;;;;;;;;;;;;;;;;;;;;; ; Paths and Directories ; ;;;;;;;;;;;;;;;;;;;;;;;;; ; UNIX: "/path1:/path2" ;include_path = ".:/php/includes" ; ; Windows: "\path1;\path2" ;include_path = ".;c:\php\includes" ; ; PHP's default setting for include_path is ".;/path/to/php/pear" ; http://php.net/include-path include_path = ".;C:\xampp\php\PEAR" I am really at a loss as to how to resolve this. I searched for a while for some documentation but most referred to installing on ubuntu. I don't know any pear or php, so if you know how to fix this please explain thoroughly. I am willing to supply as much information as needed.

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• Using classes for the first time,help in debugging

  - by kaushik

  here is post my code:this is no the entire code but enough to explain my doubt.please discard any code line which u find irrelavent enter code here saving_tree={} isLeaf=False class tree: global saving_tree rootNode=None lispTree=None def __init__(self,x): file=x string=file.readlines() #print string self.lispTree=S_expression(string) self.rootNode=BinaryDecisionNode(0,'Root',self.lispTree) class BinaryDecisionNode: global saving_tree def __init__(self,ind,name,lispTree,parent=None): self.parent=parent nodes=lispTree.getNodes(ind) print nodes self.isLeaf=(nodes[0]==1) nodes=nodes[1]#Nodes are stored self.name=name self.children=[] if self.isLeaf: #Leaf Node print nodes #Set the leaf data self.attribute=nodes print "LeafNode is ",nodes else: #Set the question self.attribute=lispTree.getString(nodes[0]) self.attribute=self.attribute.split() print "Question: ",self.attribute,self.name tree={} tree={str(self.name):self.attribute} saving_tree=tree #Add the children for i in range(1,len(nodes)):#Since node 0 is a question # print "Adding child ",nodes[i]," who has ",len(nodes)-1," siblings" self.children.append(BinaryDecisionNode(nodes[i],self.name+str(i),lispTree,self)) print saving_tree i wanted to save some data in saving_tree{},which i have declared previously and want to use that saving tree in the another function outside the class.when i asked to print saving_tree it printing but,only for that instance.i want the saving_tree{} to have the data to store data of all instance and access it outside. when i asked for print saving_tree outside the class it prints empty{}.. please tell me the required modification to get my required output and use saving_tree{} outside the class..

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• What does the destructor do silently?

  - by zhanwu

  Considering the following code which looks like that the destructor doesn't do any real job, valgrind showed me clearly that it has memory leak without using the destructor. Any body can explain me what does the destructor do in this case? #include <iostream> using namespace std; class A { private: int value; A* follower; public: A(int); ~A(); void insert(int); }; A::A(int n) { value = n; follower = NULL; } A::~A() { if (follower != NULL) delete follower; cout << "do nothing!" << endl; } void A::insert(int n) { if (this->follower == NULL) { A* f = new A(n); this->follower = f; } else this->follower->insert(n); } int main(int argc, char* argv[]) { A* objectA = new A(1); int i; for (i = 0; i < 10; i++) objectA->insert(i); delete objectA; }

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• modified closure warning in ReSharper

  - by Sarah Vessels

  I was hoping someone could explain to me what bad thing could happen in this code, which causes ReSharper to give an 'Access to modified closure' warning: bool result = true; foreach (string key in keys.TakeWhile(key => result)) { result = result && ContainsKey(key); } return result; Even if the code above seems safe, what bad things could happen in other 'modified closure' instances? I often see this warning as a result of using LINQ queries, and I tend to ignore it because I don't know what could go wrong. ReSharper tries to fix the problem by making a second variable that seems pointless to me, e.g. it changes the foreach line above to: bool result1 = result; foreach (string key in keys.TakeWhile(key => result1)) Update: on a side note, apparently that whole chunk of code can be converted to the following statement, which causes no modified closure warnings: return keys.Aggregate( true, (current, key) => current && ContainsKey(key) );

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• GridView edit problem If primary key is editable (design problem)

  - by Nassign

  I would like to ask about the design of table based on it's editability in a Grid View. Let me explain. For example, I have a table named ProductCustomerRel. Method 1 CustomerCode varchar PK ProductCode varchar PK StoreCode varchar PK Quantity int Note text So the combination of the CustomerCode, StoreCode and ProductCode must be unique. The record is displayed on a gridview. The requirement is that you can edit the customer, product and storecode but when the data is saved, the PK constraint must still persist. The problem here is it would be natural for a grid to be able to edit the 3 primary key, you can only achieve the update operation of the grid view by first deleting the row and then inserting the row with the updated data. An alternative to this is to just update the table and add a SeqNo, and just enforce the unique constraint of the 3 columns when inserting and updating in the grid view. Method 2 SeqNo int PK CustomerCode varchar ProductCode varchar StoreCode varchar Quantity int Note text My question is which of the two method is better? or is there another way to do this?

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• Space between 2 vertices on a heightmap

  - by Sietse

  First off, I am sorry for the crazy title. I couldn't really think of something else. I am working on a hobby project, it's a infinite world generated with Perlin Noise, Java and LWJGL. But I am having a problem, it is kinda hard to explain, so I made a video: http://youtu.be/D_NUBJZ_5Kw Obviously the problem is the black spaces in between all the pieces of ground. I have no idea what is causing it. I already tried making all the values doubles instead of floats, but that didn't fix it. Here is a piece of code I am using: float height2, height = (float)getHeight(x, y); height2 = (float) ((getHeight(x-1, y+1) + height) / 2); vertexhelper.addVertexColorAndTexture(x, height2, y+1, r, g, b, a, 0f, 1f); height2 = (float) ((getHeight(x+1, y+1) + height) / 2); vertexhelper.addVertexColorAndTexture(x+1, height2, y+1, r, g, b, a, 1f, 1f); height2 = (float) ((getHeight(x+1, y-1) + height) / 2); vertexhelper.addVertexColorAndTexture(x+1, height2, y, r, g, b, a, 1f, 0f); height2 = (float) ((getHeight(x-1, y-1) + height) / 2); vertexhelper.addVertexColorAndTexture(x, height2, y, r, g, b, a, 0f, 0f); I loop through this at the initialization of a chunk with x-16 and y-16. vertexhelper is a class I made that just puts everything in a array. (I am using floats here, but that's after doing the maths, so that shouldn't be a problem) I highly appreciate you reading this.

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• Calling function and running it

  - by devs

  I am quite new to objects and OOP. I really don't know how to explain it well but I'll try. So I am trying to read though JSON with JS, the JSON is passed from PHP. This would be easy if all of the information was on the same html page, but I' am trying something that I am new too. So let me show my code... First is the JS which is in app.js var Donors = function(){ var api = this.list; $(document).ready(function(){ $.getJSON(api, function(){ var donorObj = api.payload; $.each(donorObj, function(i, donor){ //console.log(donor.ign); }); }); }); } What I want this part to do is read from the JSON I'm giving it and console.log each name (or donor.ign) when the document is ready. On the html page, or header.php <script> $(function(){ var list = <?php cbProxy(); ?>; var Dons = new Donors(); Dons.list = list; }); </script> the data that's in list is the below JSON. You already know what the rest does, it just passes the JSON to the Donors() function. JSON example: { "code": 0, "payload": [ { "time": 1349661897, "packages": [ "49381" ], "ign": "Notch", "price": "15.99", "currency": "USD" } I'm use to just making functions and calling it on the same page or file and this is my first doing this kind of function. How can I get the function to run with the data I sent it so it console.log() each name.

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• C++ new memory allocation fragmentation

  - by tamulj

  I was trying to look at the behavior of the new allocator and why it doesn't place data contiguously. My code: struct ci { char c; int i; } template <typename T> void memTest() { T * pLast = new T(); for(int i = 0; i < 20; ++i) { T * pNew = new T(); cout << (pNew - pLast) << " "; pLast = pNew; } } So I ran this with char, int, ci. Most allocations were a fixed length from the last, sometimes there were odd jumps from one available block to another. sizeof(char) : 1 Average Jump: 64 bytes sizeof(int): 4 Average Jump: 16 sizeof(ci): 8 (int has to be placed on a 4 byte align) Average Jump: 9 Can anyone explain why the allocator is fragmenting memory like this? Also why is the jump for char so much larger then ints and a structure that contains both an int and char.

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• Is there a nice way of having static generic parameters is Java?

  - by Chris

  Hello, recently I'm writing some functions that I take from Haskell and translate into Java. One of the main problems I have is I cannot easily create a static property with a generic type. Let me explain by a little example... // An interface to implement functions public interface Func<P, R> { public R apply(P p); } // What I want to do... (incorrect in Java) public class ... { public static <T> Func<T, T> identity = new Func<T, T>() { public T apply(T p) { return p; } } } // What I do right now public class ... { private static Func<Object, Object> identity = new Func<Object, Object>() { public Object apply(Object p) { return p; } } @SuppressWarnings("unchecked") public static <T> Func<T, T> getIdentity() { return (Func<T, T>)identity; } } Are there any easier ways to do something like that? What kind of problems might arise if the syntax I used would be valid?

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• ASP.NET - Google Chrome caching DropDownList selections

  - by Fake

  I'm experiencing what seems to be a caching issue with Google Chrome and Safari on my cart page. In the cart there are 2 dropdown lists. When you hit the checkout button after changing the values in the dropdown lists, it commits what's selected in the lists to the database. It's a little bit hard to explain the unexpected behavior so I will try to write it out step by step with an illustration of my problem. Lets say the first dropdown list has the values of: VALUE1 VALUE2 VALUE3 And the second dropdown list has the values of: DUMBO1 DUMBO2 DUMBO3 I add an item to my cart. Screen Says: VALUE1, DUMBO1 Database Says: VALUE1, DUMBO1 I hit Checkout. Database says: VALUE1, DUMBO1 (I can't see the dropdown lists after I hit checkout because i'm not at the cart page) I hit the back button. Screen Says: VALUE1, DUMBO1 Database Says: VALUE1, DUMBO1 I drop down the VALUE1 combo and select VALUE2, VALUE2 is selected momentarily and then the site posts back and VALUE1 is re-selected in the drop down list (from being reloaded from the DB) MOMENTARILY Screen Says: VALUE2, DUMBO1 Database Says: VALUE1, DUMBO1 THEN AFTER POSTBACK FROM DROPDOWNLIST_SELECTIONCHANGED EVENT Screen Says: VALUE1, DUMBO1 Database Says: VALUE1, DUMBO1 Hit Checkout. Database Says VALUE1 ,DUMBO1 (I can't see the dropdown lists after I hit checkout because i'm not at the cart page) Go back. Screen Says: VALUE2, DUMBO1 Database Says: VALUE1, DUMBO1 So it appears that it's remembering my selection of VALUE2 even though it jumped back to VALUE1 before I checked out. It seems to be a caching problem, however I've got some no-cache code to prevent caching of that page that works great in firefox and internet explorer but seems to be failing in Chrome and Safari. I'm basically returning in the headers for the cart page: no-cache, no-store, and must-revalidate to attempt to prevent caching, but based on this scenario it seems to be caching the page anyway and not reloading it when I hit the back button. I am open to any solutions or suggestions at this point. Thanks!

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• "Address of" (&) an array / address of being ignored be gcc?

  - by dbarbosa

  Hi, I am a teaching assistant of a introductory programming course, and some students made this type of error: char name[20]; scanf("%s",&name); which is not surprising as they are learning... What is surprising is that, besides gcc warning, the code works (at least this part). I have been trying to understand and I wrote the following code: void foo(int *str1, int *str2) { if (str1 == str2) printf("Both pointers are the same\n"); else printf("They are not the same\n"); } int main() { int test[50]; foo(&test, test); if (&test == test) printf("Both pointers are the same\n"); else printf("They are not the same\n"); } Compiling and executing: $ gcc test.c -g test.c: In function ‘main’: test.c:12: warning: passing argument 1 of ‘foo’ from incompatible pointer type test.c:13: warning: comparison of distinct pointer types lacks a cast $ ./a.out Both pointers are the same Both pointers are the same Can anyone explain why they are not different? I suspect it is because I cannot get the address of an array (as I cannot have & &x), but in this case the code should not compile.

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• Why does the order of the loops affect performance when iterating over a 2D array? [closed]

  - by Mark

  Possible Duplicate: Which of these two for loops is more efficient in terms of time and cache performance Below are two programs that are almost identical except that I switched the i and j variables around. They both run in different amounts of time. Could someone explain why this happens? Version 1 #include <stdio.h> #include <stdlib.h> main () { int i,j; static int x[4000][4000]; for (i = 0; i < 4000; i++) { for (j = 0; j < 4000; j++) { x[j][i] = i + j; } } } Version 2 #include <stdio.h> #include <stdlib.h> main () { int i,j; static int x[4000][4000]; for (j = 0; j < 4000; j++) { for (i = 0; i < 4000; i++) { x[j][i] = i + j; } } }

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