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  • Issue calling superclass method in subclass constructor

    - by stormin986
    I get a NullPointerException calling a Superclass Method in Subclass Inner Class Constructor... What's the Deal? In my application's main class (subclass of Application), I have a public inner class that simply contains 3 public string objects. In the parent class I declare an object of that inner class. public class MainApplication extends Application { public class Data { public String x; public String y; public String z; } private Data data; MainApplication() { data = new Data() data.x = SuperClassMethod(); } } After I instantiate the object in the constructor, I get a runtime error when I try to assign a value in the inner class with a superclass method. Any idea what's up here?? Can you not call superclass methods in the subclass constructor? ** Edit ** Original question was about inner class member assignment in outer class constructor. Turned out the issue was with calling a superclass method in the class's constructor. It was giving me a null pointer exception. Thus, the question has changed.

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  • How to convert Unicode strings (\u00e2, etc) into NSString for display?

    - by karlbecker_com
    I am trying to support arbitrary unicode from a variety of international users. They have already put a bunch of data into sqlite databases on their iPhones, and now I want to capture the data into a database, then send it back to their device. Right now I am using a php page that is sending data back to from an internet mysql database. The data is saved in the mysql database properly, but when it's sent back it comes out as unicode text, such as Frank\u00e2\u0080\u0099s iPad instead of just Frank's iPad where the apostrophe should really be a curly apostrophe. The answer posted to another question indicates that there is no built-in Cocoa methods to convert the "\u00e2\u0080\u0099" portion of the unicode string from the webserver to an NSString object. Is this correct? That seems really surprising (and scarily disappointing), since Cocoa definitely allows input from many different Unicode characters, and I need to support any arbitrary language that I have never heard of, and all of the possible characters. I save them to and from the local sqlite database just fine now, but once I send it to a web server, then perhaps pull down different data, I want to ensure the data pulled from the web server is correctly formatted.

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  • With this generics code why am I getting "Argument 1: cannot convert from 'ToplogyLibrary.Relationsh

    - by Greg
    Hi, Any see why I'm getting a "Argument 1: cannot convert from 'ToplogyLibrary.RelationshipBase' to 'TRelationship'" in the code below, in CreateRelationship() ? public class TopologyBase<TKey, TNode, TRelationship> where TNode : NodeBase<TKey>, new() where TRelationship : RelationshipBase<TKey>, new() { // Properties public Dictionary<TKey, TNode> Nodes { get; private set; } public List<TRelationship> Relationships { get; private set; } // Constructors protected TopologyBase() { Nodes = new Dictionary<TKey, TNode>(); Relationships = new List<TRelationship>(); } // Methods public TNode CreateNode(TKey key) { var node = new TNode {Key = key}; Nodes.Add(node.Key, node); return node; } public void CreateRelationship(TNode parent, TNode child) { // Validation if (!Nodes.ContainsKey(parent.Key) || !Nodes.ContainsKey(child.Key)) { throw new ApplicationException("Can not create relationship as either parent or child was not in the graph: Parent:" + parent.Key + ", Child:" + child.Key); } // Add Relationship var r = new RelationshipBase<TNode>(); r.Parent = parent; r.Child = child; Relationships.Add(r); // *** HERE *** "Argument 1: cannot convert from 'ToplogyLibrary.RelationshipBase<TNode>' to 'TRelationship'" } } public class RelationshipBase<TNode> { public TNode Parent { get; set; } public TNode Child { get; set; } } public class NodeBase<T> { public T Key { get; set; } public NodeBase() { } public NodeBase(T key) { Key = key; } }

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  • PHP Replace chars by functions

    - by user1860570
    I try change characters by functions <?php $string = "Hi everybody people [gal~images/articles~100~100~4] here other imagen [gal~images/products~100~100~3]"; $regex = "/\[(.*?)\]/"; preg_match_all($regex, $string, $matches); for($i=0; $i<count($matches[1]);$i++) { $match = $matches[1][$i]; $array = explode('~', $match); //$newValuet="gal("".$array[1]."","".$array[2]."","".$array[3]."","".$array[4]."")"; $newValue="gal(".$array[1].",".$array[2].",".$array[3].",".$array[4].")"; $string = str_replace($matches[0][$i],$newValue,$string); } echo $string; ?> The problem here : $newValue="gal(".$array[1].",".$array[2].",".$array[3].",".$array[4].")"; $string = str_replace($matches[0][$i],$newValue,$string); Function no give the right results i try differents methods but continue the problems , please i see all functions but no get this works if you can answer please put me some modification of this code for i can understand , thank´s a lot for all help

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  • How to build a Django form which requires a delay to be re-submitted ?

    - by pierre-guillaume-degans
    Hey, In order to avoid spamming, I would like to add a waiting time to re-submit a form (i.e. the user should wait a few seconds to submit the form, except the first time that this form is submitted). To do that, I added a timestamp to my form (and a security_hash field containing the timestamp plus the settings.SECRET_KEY which ensures that the timestamp is not fiddled with). This look like: class MyForm(forms.Form): timestamp = forms.IntegerField(widget=forms.HiddenInput) security_hash = forms.CharField(min_length=40, max_length=40, widget=forms.HiddenInput) # + some other fields.. # + methods to build the hash and to clean the timestamp... # (it is based on django.contrib.comments.forms.CommentSecurityForm) def clean_timestamp(self): """Make sure the delay is over (5 seconds).""" ts = self.cleaned_data["timestamp"] if not time.time() - ts > 5: raise forms.ValidationError("Timestamp check failed") return ts # etc... This works fine. However there is still an issue: the timestamp is checked the first time the form is submitted by the user, and I need to avoid this. Any idea to fix it ? Thank you ! :-)

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  • Calling a subclass method from a superclass

    - by Shaun
    Preface: This is in the context of a Rails application. The question, however, is specific to Ruby. Let's say I have a Media object. class Media < ActiveRecord::Base end I've extended it in a few subclasses: class Image < Media def show # logic end end class Video < Media def show # logic end end From within the Media class, I want to call the implementation of show from the proper subclass. So, from Media, if self is a Video, then it would call Video's show method. If self is instead an Image, it would call Image's show method. Coming from a Java background, the first thing that popped into my head was 'create an abstract method in the superclass'. However, I've read in several places (including Stack Overflow) that abstract methods aren't the best way to deal with this in Ruby. With that in mind, I started researching typecasting and discovered that this is also a relic of Java thinking that I need to banish from my mind when dealing with Ruby. Defeated, I started coding something that looked like this: def superclass_method # logic this_media = self.type.constantize.find(self.id) this_media.show end I've been coding in Ruby/Rails for a while now, but since this was my first time trying out this behavior and existing resources didn't answer my question directly, I wanted to get feedback from more-seasoned developers on how to accomplish my task. So, how can I call a subclass's implementation of a method from the superclass in Rails? Is there a better way than what I ended up (almost) implementing?

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  • Checking for valid email addresses

    - by Roland
    I'm running a website with more than 60 000 registered users. Every week notifications are send to these users via email, now I've noticed some of the mail addresses do not exists anymore eg. the domain address is valid but the email name en asdas@ is not valid anymore since person does not work at a company anymore etc. Now I'm looping through the database and doing some regular expression checks and checking if the MX records exist with the following two functions function verify_email($email){ if(!preg_match('/^[_A-z0-9-]+((\.|\+)[_A-z0-9-]+)*@[A-z0-9-]+(\.[A-z0-9-]+)*(\.[A-z]{2,4})$/',$email)){ return false; } else { return true; } } // Our function to verify the MX records function verify_email_dns($email){ list($name, $domain) = split('@',$email); if(!checkdnsrr($domain,'MX')){ return false; } else { return true; } } If the email address is in an invalid format or the domain does not exists I delete the users account. Are there any methods I could use to check if the email address still exists or not if the domain name is valid and the email address is in the correct format? For example [email protected] does not exist anymore but test.com is a valid domain name.

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  • Scrolling to the bottom of a div on page load: issue with syntaxhighlighter

    - by Rayne
    I've been using this code: var objDiv = document.getElementById("code"); objDiv.scrollTop = objDiv.scrollHeight; to scroll to the very bottom of the div. It worked perfectly in FF and Chrome (I asked a question about it not working in Chrome a few days ago, but it appears the guy who was testing it on Chrome was incorrect, so I tested it myself) until I started syntax highlighting the code that I put in the div with SyntaxHighlighter. Before, I was putting the code in a <p> and breaking lines with <br />, but the <br /> stuff doesn't fly with SyntaxHighlighter, so I replaced all of those with newlines (not entirely certain if this is important, but it's worth mentioning). Now, when the page loads, it does scroll, but not all the way down. It scrolls nearly to the bottom. I've tried all the methods listed in the other question I mentioned but they all do the same thing, or nothing at all. Is there anything else I can try? Here is the relevant piece of the generated HTML. Forgive the poor formatting, I'm not writing the HTML by hand, but rather using Hiccup with Clojure, and it doesn't bother with formatting. <div class="scroll" id="code"><pre class="brush: clojure">=> (doseq [x (range 1 100)] (println x)) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 nil </pre></div><script type="text/javascript">var objDiv = document.getElementById("code"); objDiv.scrollTop = objDiv.scrollHeight;</script>

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  • Wordpress: How to override all default theme CSS so your custom one is loaded the last?

    - by mickael
    I have a problem where I've been able to include a custom css in the section of my wordpress theme with the following code: function load_my_style_wp_enqueue_scripts() { wp_register_style('my_styles_css', includes_url("/css/my_styles.css")); wp_enqueue_style('my_styles_css'); } add_action('wp_enqueue_scripts','load_my_style_wp_enqueue_scripts'); But the order in the source code is as follows: <link rel='stylesheet' id='my_styles_css-css' href='http://...folderA.../my_styles.css?ver=3.1' type='text/css' media='all' /> <link rel="stylesheet" id="default-css" href="http://...folderB.../default.css" type="text/css" media="screen,projection" /> <link rel="stylesheet" id="user-css" href="http://...folderC.../user.css" type="text/css" media="screen,projection" /> I want my_styles_css to be the last file to load, overriding default and user files. I've tried to achieve this by modifying wp_enqueue_style in different ways, but without any success. I've tried: wp_enqueue_style('my_styles_css', array('default','user')); or wp_enqueue_style('my_styles_css', false, array('default','user'), '1.0', 'all'); I've seen some related questions without answer or with these last 2 methods that are still failing for me. The function above is part of a plugin that I've got enabled in my wordpress installation.

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  • REST API - why use PUT DELETE POST GET?

    - by Andre
    So -i was looking through some articles on creating REST API's. And some of them suggest using all types of HTTP requests: like PUT DELETE POST GET. So - we would create for example index.php and write API this way: $method = $_SERVER['REQUEST_METHOD']; $request = split("/", substr(@$_SERVER['PATH_INFO'], 1)); switch ($method) { case 'PUT': ....some put action.... break; case 'POST': ....some post action.... break; case 'GET': ....some get action.... break; case 'DELETE': ....some delete action.... break; } Ok - granted - I don't know much baout web services (yet). But - wouldn't it be easier to just accept JSON object through normal $_POST and then respond in JSON as well. We can easily serialize/deserialize via php's json_encode and json_decode and do whatever we want with that data without having to deal with different HTTP request methods... Am I missing something? UPDATE 1: Ok - after digging through various API's and learning a lot about XML-RPC, JSON-RPC, SOAP, REST I came to a conclusion that this type of API is sound. Actually stack exchange is pretty much using this approach on their sites and I do think that these people know what they are doing Stack Exchange API.

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  • Unit Testing Private Method in Resource Managing Class (C++)

    - by BillyONeal
    I previously asked this question under another name but deleted it because I didn't explain it very well. Let's say I have a class which manages a file. Let's say that this class treats the file as having a specific file format, and contains methods to perform operations on this file: class Foo { std::wstring fileName_; public: Foo(const std::wstring& fileName) : fileName_(fileName) { //Construct a Foo here. }; int getChecksum() { //Open the file and read some part of it //Long method to figure out what checksum it is. //Return the checksum. } }; Let's say I'd like to be able to unit test the part of this class that calculates the checksum. Unit testing the parts of the class that load in the file and such is impractical, because to test every part of the getChecksum() method I might need to construct 40 or 50 files! Now lets say I'd like to reuse the checksum method elsewhere in the class. I extract the method so that it now looks like this: class Foo { std::wstring fileName_; static int calculateChecksum(const std::vector<unsigned char> &fileBytes) { //Long method to figure out what checksum it is. } public: Foo(const std::wstring& fileName) : fileName_(fileName) { //Construct a Foo here. }; int getChecksum() { //Open the file and read some part of it return calculateChecksum( something ); } void modifyThisFileSomehow() { //Perform modification int newChecksum = calculateChecksum( something ); //Apply the newChecksum to the file } }; Now I'd like to unit test the calculateChecksum() method because it's easy to test and complicated, and I don't care about unit testing getChecksum() because it's simple and very difficult to test. But I can't test calculateChecksum() directly because it is private. Does anyone know of a solution to this problem?

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  • Designing a class in such a way that it doesn't become a "God object"

    - by devoured elysium
    I'm designing an application that will allow me to draw some functions on a graphic. Each function will be drawn from a set of points that I will pass to this graphic class. There are different kinds of points, all inheriting from a MyPoint class. For some kind of points it will be just printing them on the screen as they are, others can be ignored, others added, so there is some kind of logic associated to them that can get complex. How to actually draw the graphic is not the main issue here. What bothers me is how to make the code logic such that this GraphicMaker class doesn't become the so called God-Object. It would be easy to make something like this: class GraphicMaker { ArrayList<Point> points = new ArrayList<Point>(); public void AddPoint(Point point) { points.add(point); } public void DoDrawing() { foreach (Point point in points) { if (point is PointA) { //some logic here else if (point is PointXYZ) { //...etc } } } } How would you do something like this? I have a feeling the correct way would be to put the drawing logic on each Point object (so each child class from Point would know how to draw itself) but two problems arise: There will be kinds of points that need to know all the other points that exist in the GraphicObject class to know how to draw themselves. I can make a lot of the methods/properties from the Graphic class public, so that all the points have a reference to the Graphic class and can make all their logic as they want, but isn't that a big price to pay for not wanting to have a God class?

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  • Exposed onsite vs IFD deployments for MS Dynamics CRM

    - by Greg McGuffey
    I'm working for the first time on a MS Dyanmics CRM 4.0 project. Our company has a high number of remote employees and even more remote consultants. As such it will be necessary to make the CRM solution available over the internet. As near as I can tell, I have three options: Have everyone use a VPN to access an intranet site (typical onsite deployment). However, we have found that VPNs are far from trouble free and cause many support issues. We avoid them like the plague. Use IFD to expose the CRM on the internet. I don't know much about this except that the URL will be different than the onsite URL, which could cause some headaches (see below). Expose the CRM site by opening the site to the internet, using SSL to encrypt traffic. We currently do this with our MS sharepoint sites. I'm not sure how secure this would be (one of the reasons for this question). I'd like to avoid using both the onsite intranet deployment and the IFD together for a couple of reasons. One of the requests for the solution is use email to notify users that they've been assigned a task, and include the URL to the task within the email. For this reason. If both deployments are used, then I'll need to include two URLs and the user would need to know which to use. Which leads to the second reason, the main users of the solution split time between being in the office and being remote. Thus they would need to access the solution two different ways, and know when to use which. Bad. So, what are the advantages/disadvantages of any of these methods? Any other options? Is there any issue using IFD from within the intranet? Security issues? Thanks!

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  • forward invocation, by hand vs magically?

    - by John Smith
    I have the following two class: //file FruitTree.h @interface FruitTree : NSObject { Fruit * f; Leaf * l; } @end //file FruitTree.m @implementation FruitTree //here I get the number of seeds from the object f @end //file Fruit @interface Fruit : NSObject { int seeds; } -(int) countfruitseeds; @end My question is at the point of how I request the number of seeds from f. I have two choices. Either: Since I know f I can explicitly call it, i.e. I implement the method -(int) countfruitseeds { return [f countfruitseeds]; } Or: I can just use forwardInvocation: - (NSMethodSignature *)methodSignatureForSelector:(SEL)selector { // does the delegate respond to this selector? if ([f respondsToSelector:selector]) return [f methodSignatureForSelector:selector]; else if ([l respondsToSelector:selector]) return [l methodSignatureForSelector:selector]; else return [super methodSignatureForSelector: selector]; } - (void)forwardInvocation:(NSInvocation *)invocation { [invocation invokeWithTarget:f]; } (Note this is only a toy example to ask my question. My real classes have lots of methods, which is why I am asking.) Which is the better/faster method?

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  • Help me choose a web development framework/platform that will make me learn something

    - by Sergio Tapia
    I'm having a bit of an overload of information these past two days. I'm planning to start my own website that will allow local businesses to list their items on sale, and then users can come in and search for "Abercrombie t-shirt" and the stores that sell them will be listed. It's a neat little project I'm really excited for and I'm sure it'll take off, but I'm having problems from the get go. Sure I could use ASP.Net for it, I'm a bit familiar with it and the IDE for ASP.Net pages is bar-none, but I feel this is a great chance for me to learn something new to branch out a bit and not regurgitate .NET like a robot. I've been looking and asking around but it's all just noise and I can't make an educated decision. Can you help me choose a framework/platform that will make me learn something that's a nice thing to know in the job market, but also nice for me to grow as a professional? So far I've looked at: Ruby on Rails Kohana CakePHP CodeIgniter Symfony But they are all very esoteric to me, and I have trouble even finding out which IDE to use to that will let me use auto-complete for the proprietary keywords/methods. Thank you for your time.

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  • How can I get the main thread to sleep while waiting for a delgate to be called?

    - by Erik B
    Consider a class with these methods: - (id) initWithFrame: (CGRect) frame { if (!(self = [super init])) return nil; webView = [[UIWebView alloc] initWithFrame:frame]; [webView setDelegate:self]; lock = [[NSConditionLock alloc] initWithCondition:LOCK_WAIT]; return self; } - (void) setHTML: (NSString *) html { [lock lockWhenCondition:LOCK_WAIT]; [webView loadHTMLString:html baseURL:nil]; [lock unlock]; } - (void)webViewDidFinishLoad:(UIWebView *)aWebView { [lock lockWhenCondition:LOCK_WAIT]; // Locking to be able to unlock and change the condition. [lock unlockWithCondition:LOCK_GO]; } - (NSString *) stringByEvaluatingJavaScriptFromString: (NSString *) jsCommand { [lock lockWhenCondition:LOCK_GO]; return [webView stringByEvaluatingJavaScriptFromString:jsCommand]; [lock unlock]; } Let's call this class SynchronousUIWebView. From the main thread I execute: webView = [[SynchronousUIWebView alloc] initWithFrame:frame]; [webView setHTML:html]; [webView stringByEvaluatingJavaScriptFromString:jsCommand]; The problem seems to be that the delegate is not called until I leave the current call stack, which I don't since I'm waiting for the delegate call to happen, aka deadlock. To me it seems like the delegate call is pushed to a queue that is called when the current call is done. So the question is can I modify this behavior? Note: The reason this is needed is that I can't execute the JavaScript until the HTML has loaded.

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  • Parsing XML in C# from stream

    - by Phillip
    I've tried several methods, from Linq to loading the data to an XML document, but i can't seem to be able to return the result that i need. here's the example XML: <serv:message xmlns:serv="http://www.webex.com/schemas/2002/06/service" xmlns:com="http://www.webex.com/schemas/2002/06/common" xmlns:event="http://www.webex.com/schemas/2002/06/service/event"><serv:header><serv:response><serv:result>SUCCESS</serv:result><serv:gsbStatus>PRIMARY</serv:gsbStatus></serv:response></serv:header><serv:body><serv:bodyContent xsi:type="event:createEventResponse" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><event:sessionKey>11111111</event:sessionKey><event:guestToken>111111111111111111111</event:guestToken></serv:bodyContent></serv:body></serv:message> And, here's what i've tried to do: StreamReader reader = new StreamReader(dataStream); XmlDocument doc = new XmlDocument(); doc.LoadXml(reader.ReadToEnd()); XmlNamespaceManager ns = new XmlNamespaceManager(doc.NameTable); XmlNamespaceManager ns2 = new XmlNamespaceManager(doc.NameTable); XmlNamespaceManager ns3 = new XmlNamespaceManager(doc.NameTable); ns.AddNamespace("serv", "http://www.webex.com/schemas/2002/06/service"); ns2.AddNamespace("com", "http://www.webex.com/schemas/2002/06/common"); ns3.AddNamespace("event", "http://www.webex.com/schemas/2002/06/service/event"); XmlNode node = doc.SelectSingleNode("result",ns); Yet, for some reason i cannot ever seem to return the actual result, which should be either 'SUCCESS' or 'FAILURE' based on the actual xml above. How can i do this?

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  • Visual C++ overrides/mock objects for unit testing?

    - by Mark
    When I'm running unit tests, I want to be able to "stub out" or create a mock object, but I'm running into DLL Hell. For example: There are two DLL libraries built: A.dll and B.dll -- Classes in A.dll have calls to classes in B.dll so when A.dll was built, the link line was using B.lib for the defintions. My test driver (Foo.exe) is testing classes in A.dll, so it links against A.lib. However, I want to "stub out" some of the calls A.dll makes to B.dll with simple versions (return basic value, no DB look up, etc). I can't build an Override.dll that just overrides the needed methods (not entire classes) and replace B.dll because Foo.exe will A) complain that B.dll is missing if I just remove it and put Override.dll in it's place or B) if I rename Override.dll to B.dll, Foo.exe complains that there are unresolved symbols because Override.dll is not a complete implementation of B.dll. Is there a way to do this? Is there a way to statically link Foo.exe with A.lib, B.lib and Override.lib such that it will work without having to completely rebuild A.lib and B.lib to remove the __delcspec(dllexport)? Is there another option?

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  • embed dll in html <object>

    - by Raynos
    I've come across some old code <object id="foo" classid="/location/bar.dll#ProjectName.ClassName" viewastext></object> It doesn't currently work and used to work in older versions of IE. I've never come across embedding a dll in a web page like this. It appears to be a windows .NET application written in C#. This is used on our intranet. And ClassName is of type System.Windows.Forms.UserControl It also seems I can call the C# methods of the UserControl directly through javascript. Does anyone have any documentation on how this works and whether its possible to hack it into firefox. Rewriting the windows control as a web application would be a nightmare. [Edit] It appears to be some kind of activeX / COM thing where in IE you could just port a windows application directly into a html file. It's supposed to be able to run locally if you set up various correctly. If anyone has an idea of what needs to be set up for this to work, that would be nice.

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  • What should I do if i have a factory method which requires different parameters for different implem

    - by Sam Holder
    I have an interface, IMessage and a class which have several methods for creating different types of message like so: class MessageService { IMessage TypeAMessage(param 1, param 2) IMessage TypeBMessage(param 1, param 2, param 3, param 4) IMessage TypeCMessage(param 1, param 2, param 3) IMessage TypeDMessage(param 1) } I don't want this class to do all the work for creating these messages so it simply delegates to a MessageCreatorFactory which produces an IMessageCreator depending on the type given (an enumeration based on the type of the message TypeA, TypeB, TypeC etc) interface IMessageCreator { IMessage Create(MessageParams params); } So I have 4 implementations of IMessageCreator: TypeAMessageCreator, TypeBMessageCreator, TypeCMessageCreator, TypeDMessageCreator I ok with this except for the fact that because each type requires different parameters I have had to create a MessageParams object which contains 4 properties for the 4 different params, but only some of them are used in each IMessageCreator. Is there an alternative to this? One other thought I had was to have a param array as the parameter in the Create emthod, but this seems even worse as you don't have any idea what the params are. Or to create several overloads of Create in the interface and have some of them throw an exception if they are not suitable for that particular implementation (ie you called a method which needs more params, so you should have called one of the other overloads.) Does this seem ok? Is there a better solution?

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  • How to write Java-like enums in C++ ?

    - by Rahul G
    Coming from Java background, I find C++'s enums very lame. I wanted to know how to write Java-like enums (the ones in which the enum values are objects, and can have attributes and methods) in C++. As an example, translate the following Java code (a part of it, sufficient to demonstrate the technique) to C++ : public enum Planet { MERCURY (3.303e+23, 2.4397e6), VENUS (4.869e+24, 6.0518e6), EARTH (5.976e+24, 6.37814e6), MARS (6.421e+23, 3.3972e6), JUPITER (1.9e+27, 7.1492e7), SATURN (5.688e+26, 6.0268e7), URANUS (8.686e+25, 2.5559e7), NEPTUNE (1.024e+26, 2.4746e7); private final double mass; // in kilograms private final double radius; // in meters Planet(double mass, double radius) { this.mass = mass; this.radius = radius; } private double mass() { return mass; } private double radius() { return radius; } // universal gravitational constant (m3 kg-1 s-2) public static final double G = 6.67300E-11; double surfaceGravity() { return G * mass / (radius * radius); } double surfaceWeight(double otherMass) { return otherMass * surfaceGravity(); } public static void main(String[] args) { if (args.length != 1) { System.err.println("Usage: java Planet <earth_weight>"); System.exit(-1); } double earthWeight = Double.parseDouble(args[0]); double mass = earthWeight/EARTH.surfaceGravity(); for (Planet p : Planet.values()) System.out.printf("Your weight on %s is %f%n", p, p.surfaceWeight(mass)); } } Any hep would be greatly appreciated! Thanks!

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  • How to learn how to program?

    - by twinbornJoint
    I would like to know the best methods for learning to program. I've been directed towards the Python language because I was told it is good for beginners. I ultimately want to make games for OS X/iPhone. My problem is that I understand what I read but I can't apply my knowledge to anything. I am a programming noob. Should I stick with Python? (is there a better language I should be learning?) Where can I learn programming theory? I get very hyper when reading my book sometimes, any tips on staying calm and focusing? What are effective ways to learn how to program? Are there standard exercises for programming? (I feel solving problems helps my understanding immensely) Ultimately I feel like I am in a never ending tunnel that leads me no where. It feels like I am just completely unable to pursue anything in the world of programming, yet it is something I want to do very much. Thanks.

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  • Sorting out POCO, Repository Pattern, Unit of Work, and ORM

    - by CoffeeAddict
    I'm reading a crapload on all these subjects: POCO Repository Pattern Unit of work Using an ORM mapper ok I see the basic definitions of each in books, etc. but I can't visualize this all together. Meaning an example structure (DL, BL, PL). So what, you have your DL objects that contain your CRUD methods, then your BL objects which are "mapped" using an ORM back to your DL objects? What about DTOs...they're your DL objects right? I'm confused. Can anyone really explain all this together or send me example code? I'm just trying to put this together. I am determining whether to go LINQ to SQL or EF 4 (not sure about NHibrernate yet). Just not getting the concepts as in physical layers and code layers here and what each type of object contains (just properties for DTOs, and CRUDs for your core DL classes that match the table fields???). I just need some guidance here. I'm reading Fowler's books and starting to read Evans but just not all there yet.

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  • memcache is not storing data accross requests

    - by morpheous
    I am new to using memcache, so I may be doing something wrong. I have written a wrapper class around memcache. The wrapper class has only static methods, so is a quasi singleton. The class looks something like this: class myCache { private static $memcache = null; private static $initialized = false; public static function init() { if (self::$initialized) return; self::$memcache = new Memcache(); if (self::configure()) //connects to daemon { self::store('foo', 'bar'); } else throw ConnectionError('I barfed'); } public static function store($key, $data, $flag=MEMCACHE_COMPRESSED, $timeout=86400) { if (self::$memcache->get($key)!== false) return self::$memcache->replace($key, $data, $flag, $timeout); return self::$memcache->set($key, $data, $flag, $timeout); } public static function fetch($key) { return self::$memcache->get($key); } } //in my index.php file, I use the class like this require_once('myCache.php'); myCache::init(); echo 'Stored value is: '. myCache::fetch('foo'); The problem is that the myCache::init() method is being executed in full everytime a page is requested. I then remembered that static variables do not maintain state accross page requests. So I decided instead, to store the flag that indicates whether the server contains the start up data (for our purposes, the variable 'foo', with value 'bar') in memcache itself. Once the status flag is stored in memcache itself, It solves the problem of the initialisation data being loaded for every page request (which quite frankly, defeats the purpose of memcache). However, having solved that problem, when I come to fetch the data in memcache, it is empty. I dont understand whats going on. Can anyone clarify how I can store my data once and retrieve it accross page requests? BTW, (just to clarify), the get/set is working correctly, and if I allow memcache to load the initialisation data for each page request, (which is silly), then the data is available in memcache.

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  • JTable Insert row and refresh

    - by user269723
    Hi All, I am trying to create simple application where JTable gets updated and refreshed after data is changed.Structure is as follows. 1)Class Main which contains JFrame,JTable details. 2)SampleTableModel class which extends AbstractTableModel.I am overriding most of the methods.`import javax.swing.table.; import javax.swing.event.; import java.util.*; public class SampleTableModel extends AbstractTableModel { public SampleTableModel(){ // this.addTableModelListener( } String[] columnNames = {"A","B","C","D","E"}; int[][] data = {{1,2,3,4,5},{5,6,7,8,9},{12,13,14,15,16}}; Vector dataVector = new Vector(); public Object getValueAt(int rowIndex,int columnIndex) { return data[rowIndex][columnIndex]; } public int getColumnCount(){ return 5; } public int getRowCount(){ return 3; } public String getColumnName(int columnIndex){ return columnNames[columnIndex]; } public void setValueAt(Object value,int row,int column){ data[row][column] =99; } public void notifyTable(AEMessage message){ /* * This method will be called from another class to update JTable. * */ data[0][1]=999; data[0][2]=8838; data[1][1]=8883; fireTableRowsUpdated(0,3); } } ` As you can see, notifyTable will be called from another class(which is actually a thread-which calls this method frequently) Problem is I don't see data being changed in JTable.I see only the initialized data. In the Main class- I am setting like this- RVJDataTable.setModel(new SampleTableModel());

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