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• Javascript code refactoring and assessment

  - by neitony

  I'm using javascript to toggle the display state of some objects based on the time of day. A sample of the code is given below. I was wondering if anyone could give a suggestion as to how I can refactor this code while at the same time improving the logic. switch(tcode) { case 'eur' : eur.setAttribute('style', 'display:block; opacity:0.5'); us.style.display = 'none'; asia.style.display = 'none'; us_inactive.style.display = 'block'; asia_inactive.style.display = 'block'; break; case 'us' : us.style.display = 'block'; eur.style.display = 'none'; asia.style.display = 'none'; eur_inactive.style.display = 'block'; asia_inactive.style.display = 'block'; break; case 'asia' : asia.setAttribute('style', 'display:block; opacity:0.5'); us.style.display = 'none'; eur.style.display = 'none'; eur_inactive.style.display = 'block'; us_inactive.style.display = 'block';

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• Do the 'up to date' guarantees provided by final field in Java's memory model extend to indirect ref

  - by mattbh

  The Java language spec defines semantics of final fields in section 17.5: The usage model for final fields is a simple one. Set the final fields for an object in that object's constructor. Do not write a reference to the object being constructed in a place where another thread can see it before the object's constructor is finished. If this is followed, then when the object is seen by another thread, that thread will always see the correctly constructed version of that object's final fields. It will also see versions of any object or array referenced by those final fields that are at least as up-to-date as the final fields are. My question is - does the 'up-to-date' guarantee extend to the contents of nested arrays, and nested objects? An example scenario: Thread A constructs a HashMap of ArrayLists, then assigns the HashMap to final field 'myFinal' in an instance of class 'MyClass' Thread B sees a (non-synchronized) reference to the MyClass instance and reads 'myFinal', and accesses and reads the contents of one of the ArrayLists In this scenario, are the members of the ArrayList as seen by Thread B guaranteed to be at least as up to date as they were when MyClass's constructor completed?

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• Dimensions of a collection, and how to traverse it in an efficient, elegant manner

  - by Bruce Ferguson

  I'm trying to find an elegant way to deal with multi-dimensional collections in Scala. My understanding is that I can have up to a 5 dimensional collection using tabulate, such as in the case of the following 2-Dimensional array: val test = Array.tabulate[Double](row,col)(_+_) and that I can access the elements of the array using for(i<-0 until row) { for(j<-0 until col) { test(i)(j) = 0.0 } } If I don't know a priori what I'm going to be handling, what might be a succinct way of determining the structure of the collection, and spanning it, without doing something like: case(Array(x)) => for(i<-1 until dim1) { test(i) = 0.0 } case(Array(x,y)) => for(i<-1 until dim1) { for(j<-1 until dim2) { test(i)(j) = 0.0 } } case(Array(x,y,z)) => ... The dimensional values n1, n2, n3, etc... are private, right? Also, would one use the same trick of unwrapping a 2-D array into a 1-D vector when dealing with n-Dimensional objects if I want a single case to handle the traversal? Thanks in advance Bruce

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• Mixing stored procedures and ORM

  - by Jason

  The company I work for develops a large application which is almost entirely based on stored procedures. We use classic ASP and SQL Server and the major part of the business logic is contained inside those stored procedures. For example, (I know, this is bad...) a single stored procedure can be used for different purposes (insert, update, delete, make some calculations, ...). Most of the time, a stored procedure is used for operations on related tables, but this is not always the case. We are planning to move to ASP.NET in a near future. I have read a lot of posts on StackOverflow recommending that I move the business logic outside the database. The thing is, I have tried to convince the people who takes the decisions at our company and there is nothing I can do to change their mind. Since I want to be able to use the advantages of object-oriented programming, I want to map the tables to actual classes. So far, my solution is to use an ORM (Entity Framework 4 or nHibernate) to avoid mapping the objects manually (mostly to retrieve the data) and use some kind of Data Access Layer to call the existing stored procedures (for saving). I want your advice on this. Do you think it is a good solution? Any ideas?

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• Convert enumerated records to php object

  - by Matt H

  I have a table containing a bunch of records like this: +-----------+--------+----------+ | extension | fwd_to | type | +-----------+--------+----------+ | 800 | 11111 | noanswer | | 800 | 12345 | uncond | | 800 | 22222 | unavail | | 800 | 54321 | busy | | 801 | 123 | uncond | +-----------+--------+----------+ etc The query looks like this: select fwd_to, type from forwards where extension='800'; Now I get back an array containing objects which look like the following when printed with Kohana::debug: (object) stdClass Object ( [fwd_to] => 11111 [type] => noanswer ) (object) stdClass Object ( [fwd_to] => 12345 [type] => uncond ) (object) stdClass Object ( [fwd_to] => 22222 [type] => unavail ) (object) stdClass Object ( [fwd_to] => 54321 [type] => busy ) What I'd like to do is convert this to an object of this form: (object) stdClass Object ( [busy] => 54321 [uncond] => 12345 [unavail] => 22222 [noanswer] => 11111 ) The reason being I want to then call json_encode on it. This will allow me to use jquery populate to populate a form. Is there a suggested way I can do this nicely? I'm fairly new to PHP and I'm sure this is easy but it's eluding me at the moment.

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• problem with "select new Object ... join ... where"

  - by jacob

  Hi, I'm having a problem with an HQL query Three classes ClassOne is my BusinessObject public class ClassOne { private int id; private int status; private Set<ClassTwo> classTwos; + other fields/getters/setters/constructor etc } ClassTwo is referenced in a set of ClassOne and is kind of the history of an object of ClassOne public class ClassTwo { private int id; private int oldStatus; private int newStatus; private String message; //+ getters/setters/constructor etc } ClassThree is my DTO/VO with just one classTwo (not the whole history) public class ClassThree { private int id; private int status; private ClassTwo classTwo; public ClassThree(int pId, int pStatus, ClassTwo pClassTwo) { id=pId; status=pStatus; classTwo=pClassTwo; } //+ getters/setters etc } Now I'd like to create an HQL query like this: I'd like to get all objects of ClassThree with a certain status and if it exists the newest ClassTwo with a certain newStatus. For example: I'd like to get all the DTOs (ClassThree) of ClassOne whose status is now 1, but earlier in their history it has been 2 and I'd like to have the latest ClassTwo object which has 2 as newStatus. SELECT new ClassThree(c1.id, c1.status, c2) FROM ClassOne c1 LEFT JOIN c1.classtwos c2 (...) and (...) is where I don't know what to do, I'm not even sure if it's a join / join fetch Looked around and tried quite a lot already, but no clue. Especially with the join fetch I get some Hibernate errors like org.hibernate.QueryException: query specified join fetching, but the owner of the fetched association was not present in the select list. Fetching the BusinessObject like that is no problem SELECT distinct(c1) FROM ClassOne c1 LEFT OUTER JOIN FETCH c1.classtwos c2 and I get the ClassTwos as my field. Thanks in advance, Jacob P.S.: One thing might be important, ClassTwo has no reference to ClassOne!!

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• Objective C Naming Convention for an object that owns itself

  - by Ed Marty

  With the latest releases of XCode that contain static analyzers, some of my objects are throwing getting analyzer issues reported. Specifically, I have an object that owns itself and is responsible for releasing itself, but should also be returned to the caller and possibly retained there manually. If I have a method like + (Foo) newFoo the analyzer sees the word New and reports an issue in the caller saying that newFoo is expected to return an object with retain +1, and it isn't being released anywhere. If I name it + (Foo) getFoo the analyzer reports an issue in that method, saying there's a potential leak because it's not deallocated before returning. My class basically looks like this: + (Foo *) newFoo { Foo *myFoo = [[[Foo new] retain] autorelease]; [myFoo performSelectorInBackground:@selector(bar) withObject:nil]; return myFoo; } - (void) bar { //Do something that might take awhile [self release]; } The object owns itself and when its done, will release itself, but there's nowhere that it's being stored, so the static analyzer sees it as a leak somewhere. Is there some naming or coding convention to help?

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• Is there a faster way to access a property member of a class using reflection?

  - by Ross Goddard

  I am currently using the following code to access the property of an object using reflection: Dim propInfo As Reflection.PropertyInfo = myType.GetProperty(propName) Dim objValue As Object = propInfo.GetValue(myObject, Nothing) I am having some issues with the speed since this type of code is being called many times and is causing some slowdown. I have been looking into using Refelction.Emit or dynamic methods, but I am not sure exactly how to make use of them. Background Information: I am creating a list of a subset of the properties of the object, associating then with some meta information (such as if they can be loaded from the database or xml, if they are editable, can the user see them). This is for later consumption so we can write code such as : foreach prop as BaseWrapper in graphNode.NodeProperties prop.LoadFromDataRow(dr) next The application makes heavy use of having access to this list. The problem is that on the initial load of a project, a larger number of objects are being created that make use of this, so for each object created it is looping through this code a number of times. I initially tried adding each property to the list manually, but this ran into problems with not everything being initialized at the correct time and some other issues. If there is no other good way, then I may have to rethink some of the design and see what else can be done to improve the performance.

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• Python: Calling method A from class A within class B?

  - by Tommo

  There are a number of questions that are similar to this, but none of the answers hits the spot - so please bear with me. I am trying my hardest to learn OOP using Python, but i keep running into errors (like this one) which just make me think this is all pointless and it would be easier to just use methods. Here is my code: class TheGUI(wx.Frame): def __init__(self, title, size): wx.Frame.__init__(self, None, 1, title, size=size) # The GUI is made ... textbox.TextCtrl(panel1, 1, pos=(67,7), size=(150, 20)) button1.Bind(wx.EVT_BUTTON, self.button1Click) self.Show(True) def button1Click(self, event): #It needs to do the LoadThread function! class WebParser: def LoadThread(self, thread_id): #It needs to get the contents of textbox! TheGUI = TheGUI("Text RPG", (500,500)) TheParser = WebParser TheApp.MainLoop() So the problem i am having is that the GUI class needs to use a function that is in the WebParser class, and the WebParser class needs to get text from a textbox that exists in the GUI class. I know i could do this by passing the objects around as parameters, but that seems utterly pointless, there must be a more logical way to do this that doesn't using classes seem so pointless? Thanks in advance!

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• Java Inheritance doubt in parameterised collection

  - by Gala101

  It's obvious that a parent class's object can hold a reference to a child, but does this not hold true in case of parameterised collection ?? eg: Car class is parent of Sedan So public void doSomething(Car c){ ... } public void caller(){ Sedan s = new Sedan(); doSomething(s); } is obviously valid But public void doSomething(Collection<Car> c){ ... } public void caller(){ Collection<Sedan> s = new ArrayList<Sedan>(); doSomething(s); } Fails to compile Can someone please point out why? and also, how to implement such a scenario where a function needs to iterate through a Collection of parent objects, modifying only the fields present in parent class, using parent class methods, but the calling methods (say 3 different methods) pass the collection of three different subtypes.. Ofcourse it compiles fine if I do as below: public void doSomething(Collection<Car> c){ ... } public void caller(){ Collection s = new ArrayList<Sedan>(); doSomething(s); }

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• Using map() on a _set in a template?

  - by Stuart Grimshaw

  I have two models like this: class KPI(models.Model): """KPI model to hold the basic info on a Key Performance Indicator""" title = models.CharField(blank=False, max_length=100) description = models.TextField(blank=True) target = models.FloatField(blank=False, null=False) group = models.ForeignKey(KpiGroup) subGroup = models.ForeignKey(KpiSubGroup, null=True) unit = models.TextField(blank=True) owner = models.ForeignKey(User) bt_measure = models.BooleanField(default=False) class KpiHistory(models.Model): """A historical log of previous KPI values.""" kpi = models.ForeignKey(KPI) measure = models.FloatField(blank=False, null=False) kpi_date = models.DateField() and I'm using RGraph to display the stats on internal wallboards, the handy thing is Python lists get output in a format that Javascript sees as an array, so by mapping all the values into a list like this: def f(x): return float(x.measure) stats = map(f, KpiHistory.objects.filter(kpi=1) then in the template I can simply use {{ stats }} and the RGraph code sees it as an array which is exactly what I want. [87.0, 87.5, 88.5, 90] So my question is this, is there any way I can achieve the same effect using Django's _set functionality to keep the amount of data I'm passing into the template, up until now I've been passing in a single KPI object to be graphed but now I want to pass in a whole bunch so is there anything I can do with _set {{ kpi.kpihistory_set }} dumps the whole model out, but I just want the measure field. I can't see any of the built in template methods that will let me pull out just the single field I want. How have other people handled this situation?

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• How can I determine whether or not to add project items using IWizard?

  - by taarskog

  Hi, I am generating entity wrappers in VS2010 based on dynamic objects in a CRM system. In addition to the entity code, I want to add an EntityBase of which all entities inherit from. If the file exists in the project from before, it should not be added. I am using an IWizard implementation to give the generator the object names etc. Is it possible in the IWizard implementation to determine whether or not to add an item if it exists in the project from before? How do I get a hold of the project handle and its items in or before the ShouldAddProjectItem method? My code so far (not completed): public class EntityWizardImplementation : IWizard { public void BeforeOpeningFile(ProjectItem projectItem) { //Note: Nothing here. } public void ProjectFinishedGenerating(Project project) { //Note: Nothing here. } public void ProjectItemFinishedGenerating(ProjectItem projectItem) { //Note: Nothing here. } public void RunFinished() { //Note: Nothing here. } public void RunStarted(object automationObject, Dictionary<string, string> replacementsDictionary, WizardRunKind runKind, object[] customParams) { try { var window = new WizardWindow(); // Replace parameters gathered from the wizard replacementsDictionary.Add("$crmEntity$", window.CrmEntity); replacementsDictionary.Add("$crmOrganization$", window.CrmOrganization); replacementsDictionary.Add("$crmMetadataServiceUrl$", window.CrmMetadataUrl); window.Close(); } catch (SoapException se) { MessageBox.Show(se.ToString()); } catch (Exception e) { MessageBox.Show(e.ToString()); } } public bool ShouldAddProjectItem(string filePath) { // This is where I assume it is correct to handle the preexisting file. return true; } }

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• Determining if object is visible and clickable

  - by Alan Mendelevich

  I'm looking for ways to effectively determine if a control is actually visible and clickable. I mean beyond checking Visibility property of the object. I can check RenderSize and that would be [0,0] if any of the parent elements is collapsed. So this is simple too. I can also traverse up the visual tree and see if Opacity of all elements is set to 1. What I don't know how to check nicely are these scenarios: The object is obstructed by some other object. Obviously it's possible to use FindElementsInHostCoordinates() and do computations to find out how much these objects obstruct but this could be an overkill. I can also make a "screenshot" of the object in question and "screenshot" of the whole page and check if pixels where my object should be match the actual object pixels. That sounds like an overkill too. The object is obstructed by a transparent object that still "swallows" clicks (taps). The workarounds for the first problem could still fail in this scenario. Any better ideas? Do I miss something? Thanks!

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• Hibernate CreateSQL Query Problem

  - by Shaded

  Hello All I'm trying to use hibernates built in createsql function but it seems that it doesn't like the following query. List =hibernateSession.createSQLQuery("SELECT number, location FROM table WHERE other_number IN (SELECT f.number FROM table2 AS f JOIN table3 AS g on f.number = g.number WHERE g.other_number = " + var + ") ORDER BY number").addEntity(Table.class).list(); I have a feeling it's from the nested select statement, but I'm not sure. The inner select is used elsewhere in the code and it returns results fine. This is my mapping for the first table: <hibernate-mapping> <class name="org.efs.openreports.objects.Table" table="table"> <id name="id" column="other_number" type="java.lang.Integer"> <generator class="native"/> </id> <property name="number" column="number" not-null="true" unique="true"/> <property name="location" column="location" not-null="true" unique="true"/> </class> </hibernate-mapping> And the .java public class Table implements Serializable { private Integer id;//panel_facility private Integer number; private String location; public Table() { } public void setId(Integer id) { this.id = id; } public Integer getId() { return id; } public void setNumber(Integer number) { this.number = number; } public Integer number() { return number; } public String location() { return location; } public void setLocation(String location) { this.location = location; } } Any suggestions? Edit (Added mapping)

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• Wrapping a Flash/AS3 Sprite as a Flex MXML component

  - by John

  For my game, I am making the main game view as a plain Flash/AS3 class, something like: public class GameArena extends Sprite This is simply a big rectangle in which game objects are drawn, so no need for fancy UI and I want to keep the main game engine Flex-free so I can use Sprites rather than heavier Flex components. However for the entire game/app, I do still want to use Flex for GUI/layout. So I thought I could create a Flex class subclassing UIComponent, which has a GameView object as a child... now I can use this in MXML as a standard Flex component. e.g. public class ArenaView extends UIComponent { public var gameArena:GameArena; override protected function createChildren():void { super.createChildren(); if (!gameArena) { gameArena = new GameArena(); gameArena.width = 200; gameArena.height = 200; addChild(gameArena); } } } Then I have a simple line in my main App MXML like: <logic:Arena x="0" y="0" width="50%" height="100%" name="TestArenaPanel" /> But so far while my code compiles, the Flash class isn't getting rendered. Maybe it's something simple, but I wanted to ask if this is a reasonable approach, or there is something better? BTW: I've had the "should Flex be used" conversation many times. If you want to discuss that please do so in comments, but keep answers on topic.

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• How do I pass a value to a method in Objective C

  - by user268124

  I'm new to Obj-C and I have run in to a very, very basic mental block that's making me feel a little stupid. I want to pass a variable from one method to another in an purely objective-C way. So far I'm stuck and have resorted to writing it in C. In C it goes as follows; //detect the change in the segmented switch so we can; change text - (IBAction)switchChanged:(id)sender { NSLog(@"Switch change detected"); //grab the info from the sender UISegmentedControl *selector = sender; //grab the selected segment info from selector. This returns a 0 or a 1. int selectorIndex = [selector selectedSegmentIndex]; changeText (selectorIndex); } int changeText (int selectorPosition) { NSLog(@"changeText received a value. Selector position is %d", selectorPosition); //Idea is to receive a value from the segmented controler and change the screen text accordingly return 0; } This works perfectly well, but I want to learn how to do this with objects and messages. How would I rewrite these two methods to do this? Cheers Rich

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• Handling nulls in Datawarehouse

  - by rrydman

  I'd like to ask your input on what the best practice is for handling null or empty data values when it pertains to data warehousing and SSIS/SSAS. I have several fact and dimension tables that contain null values in different rows. Specifics: 1) What is the best way to handle null date/times values? Should I make a 'default' row in my time or date dimensions and point SSIS to the default row when there is a null found? 2) What is the best way to handle nulls/empty values inside of dimension data. Ex: I have some rows in an 'Accounts' dimensions that have empty (not NULL) values in the Account Name column. Should I convert these empty or null values inside the column to a specific default value? 3) Similar to point 1 above - What should I do if I end up with a Facttable row that has no record in one of the dimension columns? Do I need default dimension records for each dimension in case this happens? 4) Any suggestion or tips in regards to how to handle these operation in Sql server integration services (SSIS)? Best data flow configurations or best transformation objects to use would be helpful. Thanks :-)

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• Reference problem when returning an object from array in PHP

  - by avastreg

  I've a reference problem; the example should be more descriptive than me :P I have a class that has an array of objects and retrieve them through a key (string), like an associative array: class Collection { public $elements; function __construct() { $this->elements = array(); } public function get_element($key) { foreach($this->elements as $element) { if ($element->key == $key) { return $element; break; } } return null; } public function add_element ($element) { $this->elements[] = $element; } } Then i have an object (generic), with a key and some variables: class Element { public $key; public $another_var; public function __construct($key) { $this->key = $key; $this->another_var = "default"; } } Now, i create my collection: $collection = new Collection(); $collection->add_element(new Element("test1")); $collection->add_element(new Element("test2")); And then i try to change variable of an element contained in my "array": $element = $collection->get_element("test1"); $element->another_var = "random_string"; echo $collection->get_element("test1")->another_var; Ok, the output is random_string so i know that my object is passed to $element in reference mode. But if i do, instead: $element = $collection-get_element("test1"); $element = null; //or $element = new GenericObject(); $element-another_var = "bla"; echo $collection-get_element("test1")-another_var; the output is default like if it lost the reference. So, what's wrong? I have got the references to the variables of the element and not to the element itself? Any ideas?

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• FLEX: how to better align my Tile component to the puppet (and how to solve roll over out effects) ?

  - by Patrick

  hi, At the moment my Puppets are larger on the left if I add them the <mx:Tile> component (with tags): http://dl.dropbox.com/u/72686/puppets.png how can I move my Tile component to the right ? In order to align with the left border of my puppets ? <mx:Tile id="tagsPopup" width="200" visible="false" > <mx:LinkButton label="Tag1" /> <mx:LinkButton label="Tag2" /> <mx:LinkButton label="Tag3" /> <mx:LinkButton label="Tag4" /> </mx:Tile> <mx:VBox verticalGap="0"> <mx:Image id="puppet" source="@Embed(source='../icons/userIcon.png')" /> <mx:Label id="username" text="Nickname" visible="false" fontWeight="bold" /> </mx:VBox> 2nd Question: I want to add objects on top of the puppets, some of them are visible only when the mouse is over, and they are overlying the ones are permanently visible. How do you suggest to implement it ? I was thinking to add in MXML all visible elements and then use Actionscript to add the fade in fade out components. However I just realize it is quite tricky, because I want the user select for example tag1, tag2 and tag3, with the mouse. Instead now they disappear when the mouse rolls out from the puppet image. Any guideline ? thanks

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• find nearest match to array of doubles

  - by Scott

  Given the code below, how do I compare a List of objects's values with a test value? I'm building a geolocation application. I'll be passing in longitude and latitude and would like to have the service answer back with the location closest to those values. I started down the path of converting to a string, and formatting the values down to two decimal places, but that seemed a bit too ghetto, and I'm looking for a more elegant solution. public class Location : IEnumerable { public string label { get; set; } public double lat { get; set; } public double lon { get; set; } //Implement IEnumerable public IEnumerator GetEnumerator() { return (IEnumerator)this; } } [HandleError] public class HomeController : Controller { private List<Location> myList = new List<Location> { new Location { label="Atlanta Midtown", lon=33.657674, lat=-84.423130}, new Location { label="Atlanta Airport", lon=33.794151, lat=-84.387228}, new Location { label="Stamford, CT", lon=41.053758, lat=-73.530979}, ... } public static int Main(String[] args) { string inLat = "-80.987654"; double dblInLat = double.Parse(inLat); // here's where I would like to find the closest location to the inLat // once I figure out this, I'll implement the Longitude, and I'll be set }

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• How do I subtract two dates in Django/Python?

  - by Ryan

  Hi! I'm working on a little fitness tracker in order to teach myself Django. I want to graph my weight over time, so I've decided to use the Python Google Charts Wrapper. Google charts require that you convert your date into a x coordinate. To do this I want to take the number of days in my dataset by subtracting the first weigh-in from the last weigh-in and then using that to figure out the x coords (for example, I could 100 by the result and increment the x coord by the resulting number for each y coord.) Anyway, I need to figure out how to subtract Django datetime objects from one another and so far, I am striking out on both google and here at the stack. I know PHP, but have never gotten a handle on OO programming, so please excuse my ignorance. Here is what my models look like: class Goal(models.Model): goal_weight = models.DecimalField("Goal Weight",max_digits=4, decimal_places=1) target_date = models.DateTimeField("Target Date to Reach Goal") set_date = models.DateTimeField("When did you set your goal?") comments = models.TextField(blank=True) def __unicode__(self): return unicode(self.goal_weight) class Weight(models.Model): """Weight at a given date and time """ goal = models.ForeignKey(Goal) weight = models.DecimalField("Current Weight",max_digits=4, decimal_places=1) weigh_date = models.DateTimeField("Date of Weigh-In") comments = models.TextField(blank=True) def __unicode__(self): return unicode(self.weight) def recorded_today(self): return self.date.date() == datetime.date.today() Any ideas on how to proceed in the view? Thanks so much!

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• C++/Qt - Memory allocation question

  - by HardCoder1986

  Hello! I recently started investigating Qt for myself and have the following question: Suppose I have some QTreeWidget* widget. At some moment I want to add some items to it and this is done via the following call: QList<QTreeWidgetItem*> items; // Prepare the items QTreeWidgetItem* item1 = new QTreeWidgetItem(...); QTreeWidgetItem* item2 = new QTreeWidgetItem(...); items.append(item1); items.append(item2); widget->addTopLevelItems(items); So far it looks ok, but I don't actually understand who should control the objects' lifetime. I should explain this with an example: Let's say, another function calls widget->clear();. I don't know what happens beneath this call but I do think that memory allocated for item1 and item2 doesn't get disposed here, because their ownage wasn't actually transfered. And, bang, we have a memory leak. The question is the following - does Qt have something to offer for this kind of situation? I could use boost::shared_ptr or any other smart pointer and write something like shared_ptr<QTreeWidgetItem> ptr(new QTreeWidgetItem(...)); items.append(ptr.get()); but I don't know if the Qt itself would try to make explicit delete calls on my pointers (which would be disastrous since I state them as shared_ptr-managed). How would you solve this problem? Maybe everything is evident and I miss something really simple?

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• JSF getter methods called BEFORE beforePhase fires

  - by Bill Leeper

  I got a recommendation to put all data lookups in the beforePhase for a given page, however, now that I am doing some deeper analysis it appears that some getter methods are being called before the beforePhase is fired. It became very obvious when I added support for a url parameter and I was getting NPEs on objects that are initialized in the beforePhase call. Any thoughts? Something I have set wrong. I have this in my JSP page: <f:view beforePhase="#{someController.beforePhaseSummary}"> That is only the 5th line in the JSP file and is right after the taglibs. Here is the code that is in the beforePhaseSummary method: public void beforePhaseSummary(PhaseEvent event) { logger.debug("Fired Before Phase Summary: " + event.getPhaseId()); if (event.getPhaseId() == PhaseId.RENDER_RESPONSE) { HttpServletRequest request = (HttpServletRequest)FacesContext.getCurrentInstance().getExternalContext().getRequest(); if (request.getParameter("application_id") != null) { loadApplication(Long.parseLong(request.getParameter("application_id"))); } /* Do data fetches here */ } } The logging output above indicates that an event is fired. The servlet request is used to capture the url parameters. The data fetches gather data. However, the logging output is below: 2010-04-23 13:44:46,968 [http-8080-4] DEBUG ...SomeController 61 - Get Permit 2010-04-23 13:44:46,968 [http-8080-4] DEBUG ...SomeController 107 - Getting UnsubmittedCount 2010-04-23 13:44:46,984 [http-8080-4] DEBUG ...SomeController 61 - Get Permit 2010-04-23 13:44:47,031 [http-8080-4] DEBUG ...SomeController 133 - Fired Before Phase Summary: RENDER_RESPONSE(6) The logs indicate 2 calls to the getPermit method and one to getUnsubmittedCount before the beforePhase is fired.

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• What is the fastest (to access) struct-like object in Python?

  - by DNS

  I'm optimizing some code whose main bottleneck is running through and accessing a very large list of struct-like objects. Currently I'm using namedtuples, for readability. But some quick benchmarking using 'timeit' shows that this is really the wrong way to go where performance is a factor: Named tuple with a, b, c: >>> timeit("z = a.c", "from __main__ import a") 0.38655471766332994 Class using __slots__, with a, b, c: >>> timeit("z = b.c", "from __main__ import b") 0.14527461047146062 Dictionary with keys a, b, c: >>> timeit("z = c['c']", "from __main__ import c") 0.11588272541098377 Tuple with three values, using a constant key: >>> timeit("z = d[2]", "from __main__ import d") 0.11106188992948773 List with three values, using a constant key: >>> timeit("z = e[2]", "from __main__ import e") 0.086038238242508669 Tuple with three values, using a local key: >>> timeit("z = d[key]", "from __main__ import d, key") 0.11187358437882722 List with three values, using a local key: >>> timeit("z = e[key]", "from __main__ import e, key") 0.088604143037173344 First of all, is there anything about these little timeit tests that would render them invalid? I ran each several times, to make sure no random system event had thrown them off, and the results were almost identical. It would appear that dictionaries offer the best balance between performance and readability, with classes coming in second. This is unfortunate, since, for my purposes, I also need the object to be sequence-like; hence my choice of namedtuple. Lists are substantially faster, but constant keys are unmaintainable; I'd have to create a bunch of index-constants, i.e. KEY_1 = 1, KEY_2 = 2, etc. which is also not ideal. Am I stuck with these choices, or is there an alternative that I've missed?

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• Any workarounds for non-static member array initialization?

  - by TomiJ

  In C++, it's not possible to initialize array members in the initialization list, thus member objects should have default constructors and they should be properly initialized in the constructor. Is there any (reasonable) workaround for this apart from not using arrays? [Anything that can be initialized using only the initialization list is in our application far preferable to using the constructor, as that data can be allocated and initialized by the compiler and linker, and every CPU clock cycle counts, even before main. However, it is not always possible to have a default constructor for every class, and besides, reinitializing the data again in the constructor rather defeats the purpose anyway.] E.g. I'd like to have something like this (but this one doesn't work): class OtherClass { private: int data; public: OtherClass(int i) : data(i) {}; // No default constructor! }; class Foo { private: OtherClass inst[3]; // Array size fixed and known ahead of time. public: Foo(...) : inst[0](0), inst[1](1), inst[2](2) {}; }; The only workaround I'm aware of is the non-array one: class Foo { private: OtherClass inst0; OtherClass inst1; OtherClass inst2; OtherClass *inst[3]; public: Foo(...) : inst0(0), inst1(1), inst2(2) { inst[0]=&inst0; inst[1]=&inst1; inst[2]=&inst2; }; }; Edit: It should be stressed that OtherClass has no default constructor, and that it is very desirable to have the linker be able to allocate any memory needed (one or more static instances of Foo will be created), using the heap is essentially verboten. I've updated the examples above to highlight the first point.

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