Search Results

Search found 45436 results on 1818 pages for 'singleton class'.

Page 51/1818 | < Previous Page | 47 48 49 50 51 52 53 54 55 56 57 58  | Next Page >

  • Java - Class type from inside static initialization block

    - by DutrowLLC
    Is it possible to get the class type from inside the static initialization block? This is a simplified version of what I currently have:: class Person extends SuperClass { String firstName; static{ // This function is on the "SuperClass": // I'd for this function to be able to get "Person.class" without me // having to explicitly type it in but "this.class" does not work in // a static context. doSomeReflectionStuff(Person.class); // IN "SuperClass" } } This is closer to what I am doing, which is to initialize a data structure that holds information about the object and its annotations, etc... Perhaps I am using the wrong pattern? public abstract SuperClass{ static void doSomeReflectionStuff( Class<?> classType, List<FieldData> fieldDataList ){ Field[] fields = classType.getDeclaredFields(); for( Field field : fields ){ // Initialize fieldDataList } } } public abstract class Person { @SomeAnnotation String firstName; // Holds information on each of the fields, I used a Map<String, FieldData> // in my actual implementation to map strings to the field information, but that // seemed a little wordy for this example static List<FieldData> fieldDataList = new List<FieldData>(); static{ // Again, it seems dangerous to have to type in the "Person.class" // (or Address.class, PhoneNumber.class, etc...) every time. // Ideally, I'd liken to eliminate all this code from the Sub class // since now I have to copy and paste it into each Sub class. doSomeReflectionStuff(Person.class, fieldDataList); } }

    Read the article

  • Development/runtime Licensing mechanism for a C# class library?

    - by Darryl
    I'm developing a .Net class library (a data provider) and I'm starting to think about how I would handle licensing the library to prospective purchasers. By licensing, I mean the mechanics of trying to prevent my library from being used by those who haven't purchased it, not the software license (i.e., Apache, Gnu, etc). I've never dealt with licensing, and in the past, I've always developed apps, not libraries. I don't want to make things difficult for my customers; know it is not possible to make it ironclad. Just some mechanism that gives me decent protection without making the customer jump through hoops or gnash their teeth. I think the mechanism would check for a valid license when the class is being used in development mode, and not in runtime mode (when the customer's software is released to their customers). I think libraries are typically sold per developer, but I'm not sure how that could be accomplished without making the mechanism odious for my customers; maybe that gets left to the honor system. I Googled this and found many approaches. Ideally, I'd like to do something that is generally accepted and common, the "right" way class libraries are licensed, if that exists, rather than making my customers deal with yet another license mechanism. A firm push in the right direction will be greatly appreciated!

    Read the article

  • Dynamically class creating by using Java Reflection, java.lang.ClassNotFoundException

    - by rubby
    Hi all; i want to use reflection in java, i want to do that third class will read the name of the class as String from console. Upon reading the name of the class, it will automatically and dynamically (!) generate that class and call its writeout method. If that class is not read from input, it will not be initialized. I wrote that codes but i am always taking to "java.lang.Class.Not.Found.Exception", and i don't know how i can fix it. Can anyone help me? class class3 { public Object dynamicsinif(String className, String fieldName, String value) throws Exception { Class cls = Class.forName(className,true,null); Object obj = cls.newInstance(); Field fld = cls.getField(fieldName); fld.set(obj, value); return obj; } public void writeout3() { System.out.println("class3"); } } public class Main { public static void main(String[] args) throws Exception { System.out.println("enter the class name : "); BufferedReader reader= new BufferedReader(new InputStreamReader(System.in)); String line=reader.readLine(); String x="Text1"; try{ class3 trycls=new class3(); Object gelen=trycls.dynamicsinif(line, x, "rubby"); Class yeni=(Class)gelen; System.out.println(yeni); }catch(ClassNotFoundException ex){ System.out.print(ex.toString()); } } }

    Read the article

  • Could this be considered a well-written PHP5 class?

    - by Ben Dauphinee
    I have been learning OOP principals on my own for a while, and taken a few cracks at writing classes. What I really need to know now is if I am actually using what I have learned correctly, or if I could improve as far as OOP is concerned. I have chopped a massive portion of code out of a class that I have been working on for a while now, and pasted it here. To all you skilled and knowledgeable programmers here I ask: Am I doing it wrong? class acl extends genericAPI{ // -- Copied from genericAPI class protected final function sanityCheck($what, $check, $vars){ switch($check){ case 'set': if(isset($vars[$what])){return(1);}else{return(0);} break; } } // --------------------------------- protected $db = null; protected $dataQuery = null; public function __construct(Zend_Db_Adapter_Abstract $db, $config = array()){ $this->db = $db; if(!empty($config)){$this->config = $config;} } protected function _buildQuery($selectType = null, $vars = array()){ // Removed switches for simplicity sake $this->dataQuery = $this->db->select( )->from( $this->config['table_users'], array('tf' => '(CASE WHEN count(*) > 0 THEN 1 ELSE 0 END)') )->where( $this->config['uidcol'] . ' = ?', $vars['uid'] ); } protected function _sanityRun_acl($sanitycheck, &$vars){ switch($sanitycheck){ case 'uid_set': if(!$this->sanityCheck('uid', 'set', $vars)){ throw new Exception(ERR_ACL_NOUID); } $vars['uid'] = settype($vars['uid'], 'integer'); break; } } private function user($action = null, $vars = array()){ switch($action){ case 'exists': $this->_sanityRun_acl('uid_set', $vars); $this->_buildQuery('user_exists_idcheck', $vars); return($this->db->fetchOne($this->dataQuery->__toString())); break; } } public function user_exists($uid){ return($this->user('exists', array('uid' => $uid))); } } $return = $acl_test->user_exists(1);

    Read the article

  • Could this be considered a well-written class (am I using OOP correctly)?

    - by Ben Dauphinee
    I have been learning OOP principals on my own for a while, and taken a few cracks at writing classes. What I really need to know now is if I am actually using what I have learned correctly, or if I could improve as far as OOP is concerned. I have chopped a massive portion of code out of a class that I have been working on for a while now, and pasted it here. To all you skilled and knowledgeable programmers here I ask: Am I doing it wrong? class acl extends genericAPI{ // -- Copied from genericAPI class protected final function sanityCheck($what, $check, $vars){ switch($check){ case 'set': if(isset($vars[$what])){return(1);}else{return(0);} break; } } // --------------------------------- protected $db = null; protected $dataQuery = null; public function __construct(Zend_Db_Adapter_Abstract $db, $config = array()){ $this->db = $db; if(!empty($config)){$this->config = $config;} } protected function _buildQuery($selectType = null, $vars = array()){ // Removed switches for simplicity sake $this->dataQuery = $this->db->select( )->from( $this->config['table_users'], array('tf' => '(CASE WHEN count(*) > 0 THEN 1 ELSE 0 END)') )->where( $this->config['uidcol'] . ' = ?', $vars['uid'] ); } protected function _sanityRun_acl($sanitycheck, &$vars){ switch($sanitycheck){ case 'uid_set': if(!$this->sanityCheck('uid', 'set', $vars)){ throw new Exception(ERR_ACL_NOUID); } $vars['uid'] = settype($vars['uid'], 'integer'); break; } } private function user($action = null, $vars = array()){ switch($action){ case 'exists': $this->_sanityRun_acl('uid_set', $vars); $this->_buildQuery('user_exists_idcheck', $vars); return($this->db->fetchOne($this->dataQuery->__toString())); break; } } public function user_exists($uid){ return($this->user('exists', array('uid' => $uid))); } } $return = $acl_test->user_exists(1);

    Read the article

  • Are there any other ways to iterate through the attributes of a custom class, excluding the in-built ones?

    - by Ricardo Altamirano
    Is there another way to iterate through only the attributes of a custom class that are not in-built (e.g. __dict__, __module__, etc.)? For example, in this code: class Terrain: WATER = -1 GRASS = 0 HILL = 1 MOUNTAIN = 2 I can iterate through all of these attributes like this: for key, value in Terrain.__dict__.items(): print("{: <11}".format(key), " --> ", value) which outputs: MOUNTAIN --> 2 __module__ --> __main__ WATER --> -1 HILL --> 1 __dict__ --> <attribute '__dict__' of 'Terrain' objects> GRASS --> 0 __weakref__ --> <attribute '__weakref__' of 'Terrain' objects> __doc__ --> None If I just want the integer arguments (a rudimentary version of an enumerated type), I can use this: for key, value in Terrain.__dict__.items(): if type(value) is int: # type(value) == int print("{: <11}".format(key), " --> ", value) this gives the expected result: MOUNTAIN --> 2 WATER --> -1 HILL --> 1 GRASS --> 0 Is it possible to iterate through only the non-in-built attributes of a custom class independent of type, e.g. if the attributes are not all integral. Presumably I could expand the conditional to include more types, but I want to know if there are other ways I'm missing.

    Read the article

  • which scope should a DAO typically have.

    - by Andreas Petersson
    its out of question that a dao will not hold any state. however, for easiest access to the class, is it better to use prototype( = new every time) or singleton? simple object creation is cheap for dao's.. it typically only holds a sessionfactory, accessing the object from a list of singletons may be equally expensive. clarfication: the focus of this question is, if there is a common convention to the scoping of daos.

    Read the article

  • How long will an ASP.NET MVC application run

    - by Christoph
    I wonder how long will an ASP.NET (MVC) application run, when no new requests come in? Lets say I'm using an IOC Container ans have a Singleton Object serving to the clients. As far as I know it will serve different page requests. But how long will it live when no new request come in? Is there any timeout (maybe configured through IIS) that says when my app will shut down?

    Read the article

  • What is so bad about Singletons

    - by Ewan Makepeace
    The Singleton pattern is a fully paid up member of the GoF Patterns Book but lately seems rather orphaned by the developer world. I still use quite a lot of singletons, especially for Factory classes, and while you have to be a bit careful about multithreading issues (like any class actually) fail to see why they are so awful. This site especially seems to assume that everyone agrees that Singletons are evil. Why?

    Read the article

  • Zend_Registry - Do you need getInstance() ?

    - by Jesse
    Hey I'm wondering when accessing Zend_Registry in an application if you need to include getInstance() and if so, why? for example Zend_Registry::getInstance()-get('db'); vs. Zend_Registry::get('db'); they both seem to work with the later being less verbose. I vaguely understand that Zend_Registry is a singleton, which I think means there can only be one instance of it? so why would you need getInstance()?

    Read the article

  • Invariant code contracts – using class-wide contracts

    - by DigiMortal
    It is possible to define invariant code contracts for classes. Invariant contracts should always hold true whatever member of class is called. In this posting I will show you how to use invariant code contracts so you understand how they work and how they should be tested. This is my randomizer class I am using to demonstrate code contracts. I added one method for invariant code contracts. Currently there is one contract that makes sure that random number generator is not null. public class Randomizer {     private IRandomGenerator _generator;       private Randomizer() { }       public Randomizer(IRandomGenerator generator)     {         _generator = generator;     }       public int GetRandomFromRangeContracted(int min, int max)     {         Contract.Requires<ArgumentOutOfRangeException>(             min < max,             "Min must be less than max"         );           Contract.Ensures(             Contract.Result<int>() >= min &&             Contract.Result<int>() <= max,             "Return value is out of range"         );           return _generator.Next(min, max);     }       [ContractInvariantMethod]     private void ObjectInvariant()     {         Contract.Invariant(_generator != null);     } } Invariant code contracts are define in methods that have ContractInvariantMethod attribute. Some notes: It is good idea to define invariant methods as private. Don’t call invariant methods from your code because code contracts system does not allow it. Invariant methods are defined only as place where you can keep invariant contracts. Invariant methods are called only when call to some class member is made! The last note means that having invariant method and creating Randomizer object with null as argument does not automatically generate exception. We have to call at least one method from Randomizer class. Here is the test for generator. You can find more about contracted code testing from my posting Code Contracts: Unit testing contracted code. There is also explained why the exception handling in test is like it is. [TestMethod] [ExpectedException(typeof(Exception))] public void Should_fail_if_generator_is_null() {     try     {         var randomizer = new Randomizer(null);         randomizer.GetRandomFromRangeContracted(1, 4);     }     catch (Exception ex)     {         throw new Exception(ex.Message, ex);     } } Try out this code – with unit tests or with test application to see that invariant contracts are checked as soon as you call some member of Randomizer class.

    Read the article

  • Third-Grade Math Class

    - by andyleonard
    An Odd Thing Happened... ... when I was in third grade math class: I was handed a sheet of arithmetic problems to solve. There were maybe 20 problems on the page and we were given the remainder of the class to complete them. I don't remember how much time remained in the class, I remember I finished working on the problems before my classmates. That wasn't the odd part. The odd part was that I started working on the first problem, concentrating pretty hard. I worked the sum and moved to the next...(read more)

    Read the article

  • Ways to ensure unique instances of a class?

    - by Peanut
    I'm looking for different ways to ensure that each instance of a given class is a uniquely identifiable instance. For example, I have a Name class with the field name. Once I have a Name object with name initialised to John Smith I don't want to be able to instantiate a different Name object also with the name as John Smith, or if instantiation does take place I want a reference to the orginal object to be passed back rather than a new object. I'm aware that one way of doing this is to have a static factory that holds a Map of all the current Name objects and the factory checks that an object with John Smith as the name doesn't already exist before passing back a reference to a Name object. Another way I could think of off the top of my head is having a static Map in the Name class and when the constructor is called throwing an exception if the value passed in for name is already in use in another object, however I'm aware throwing exceptions in a constructor is generally a bad idea. Are there other ways of achieving this?

    Read the article

  • Best practice to propagate preferences of application

    - by Shebuka
    What is your approach with propagation to all classes/windows of preferences/settings of your application? Do you share the preference_manager class to all classes/windows who need it or you make variables in each classes/windows and update them manually each time setting are changed? Currently I have a PreferencesInterface class that hold all preferences and is responsible to default all values with a dedicated method called on create and when needed, all values are public, so non getters/setters, also it have virtual SavePreferences/LoadPreferences methods. Then I have PreferencesManager that extends from PreferencesInterface and is responsible for actually implementation of SavePreferences/LoadPreferences. I've made this basically for cross-platform so that every platform can have a different implementation of actual storage (registry, ini, plist, xml, whatever).

    Read the article

  • How to name an subclass that add a minor, detailed thing?

    - by Louis Rhys
    What is the most concise (yet descriptive) way of naming a subclass that only add a specific minor thing to the parent? I encountered this case a lot in WPF, where sometime I have to add a small functionality to an out-of-the-box control for specific cases. Example: TreeView doesn't change the SelectedItem on right-click, but I have to make one that does in my application. Some possible names are TreeViewThatChangesSelectedItemOnRightClick (way too wordy and maybe difficult to read because there is so many words concantenated together) TreeView_SelectedItemChangesOnRightClick (slightly more readable, but still too wordy and the underscore also breaks the normal convention for class names) TreeViewThatChangesSIOnRC (non-obvious acronym), ExtendedTreeView (more concise, but doesn't describe what it is doing. Besides, I already found a class called this in the library, that I don't want to use/modify in my application). LouisTreeView, MyTreeView, etc. (doesn't describe what it is doing). It seems that I can't find a name which sounds right. What do you do in situation like this?

    Read the article

  • Should a domain expert make class diagrams?

    - by Matthieu
    The domain expert in our team uses UML class diagrams to model the domain model. As a result, the class diagrams are more of technical models rather than domain models (it serves of some sort of technical specifications for developpers because they don't have to do any conception, they just have to implement the model). In the end, the domain expert ends up doing the job of the architect/technical expert right? Is it normal for a domain expert (not a developer or technical profile) to do class diagrams? If not, what kind of modeling should he be using?

    Read the article

  • Why use link classes in oql instead of classes that contain links

    - by Isaac
    itop abstracts its very complex database design with an object query language (oql). For this there are classes definded, like 'Ticket' and 'Server'. Now a Ticket usually is linked to a Server. In my naive way I would give the Ticket class an attribute 'affected_server_list', where I could reference the affected servers. itop does it different: neither Servers nor Tickets know of each other. Instead there is a class 'linkTicketToServer', which provides the link between the two. The first thing I noticed is that it makes oql queries more complex. So I wondered why they designed it this way. One thing that occured to me is that it allows for more flexiblity, in that I can add links without modifying the original classes. Is this allready why one would implement it this way, or are there other reasons for this kind of design?

    Read the article

  • Exporting XNA class library as a DLL file

    - by Will Bagley
    I have downloaded an open source project that I intend to use with my current game. The download came with all the class files from the original project as well as a pre-compiled DLL file representing the project. I was able to easily link this DLL with my current project and get it working just fine, no problems there. The problem I now have is that I want to make a couple of changes to the original libraries (extend its functionality a bit to better suit my needs) and re-export the class library as a DLL again, but I have no clue how to do this. Is there some simple way in VS where I can just take the class library and export/compile it as a DLL file again or is there more to it than that? This seems like something that should be pretty simple but my efforts to find an answer have so far come up with nothing. Thanks in advance.

    Read the article

  • UML Class diagrams with Java packages?

    - by loosebruce
    I am trying to model in UML 2.0 a Java servlet application that has three classes Servlet class; essentially a main class that acts as the controller DatabaseLogic; contains methods for database operations XMLBuilder; builds an XML from a query result string The classes use a variety of packages from the Java library. I am unsure how to model this in UML Do I have to create a package and show which libraries are used for each individual class or can I just have one large package in the diagram with all the libraries showing which classes have dependencies on which. As per this diagram This is my first time working with java properly (im a C++ guy) Apart from being a bit messy , is this a correct UML representation of the system I described? Does a Package in UML mean the same as a Package in Java?

    Read the article

  • Torque2D, Class vs Datablock

    - by Max Kielland
    I'm scripting my first game with Torque2D and have not fully understood the difference between "Class" and Datablock. To me it seems like Datablock is similar to a struct in C/C++ or a Record in Pascal. If I create Datablocks with new, are they instantiated in the same way as a "Class"? I have a large TileMap and need to attach some information to each Tile. I was thinking to use a Datablock, as a struct, to attach this information to the tile's CustomData property. The two questions are: What is a Datablock and should I use a Datablock or a "Class" for this tile information?

    Read the article

  • Is it evil to model JSON responses to classes when they are mostly smilar?

    - by Aybe
    Here's the problem : While implementing a C# wrapper for an online API (Discogs) I've been faced to a dilemma : quite often the responses returned have mostly similar members and while modeling these responses to classes, some questions surfaces on which way to go would be the best. Example : Querying for a 'release' or a 'master' will return an object that contains an array of 'artist', however these 'artists' do not exactly have the same members. Currently I decided to represent these 'artists' as a single 'Artist' class, against having respective 'ReleaseArtist' and 'MasterArtist' classes which soon becomes very confusing even though another problem arises : when a category (master or release) does not return these members, they will be null. Though it might sound confusing as well I find it less confusing than the former situation as I've tackled the problem by simply not showing null members when visualizing these objects. Is this the right approach to follow ? An example of these differences : public class Artist { public List<Alias> Aliases { get; set; } public string DataQuality { get; set; } public List<Image> Images { get; set; } public string Name { get; set; } public List<string> NameVariations { get; set; } public string Profile { get; set; } public string Realname { get; set; } public string ReleasesUrl { get; set; } public string ResourceUrl { get; set; } public string Uri { get; set; } public List<string> Urls { get; set; } } public class ReleaseArtist { public string Join { get; set; } public string Name { get; set; } public string Anv { get; set; } public string Tracks { get; set; } public string Role { get; set; } public string ResourceUrl { get; set; } public int Id { get; set; } }

    Read the article

  • Why should a class be anything other than "abstract" or "final/sealed"

    - by Nicolas Repiquet
    After 10+ years of java/c# programming, I find myself creating either: abstract classes: contract not meant to be instantiated as-is. final/sealed classes: implementation not meant to serve as base class to something else. I can't think of any situation where a simple "class" (i.e. neither abstract nor final/sealed) would be "wise programming". Why should a class be anything other than "abstract" or "final/sealed" ? EDIT This great article explains my concerns far better than I can.

    Read the article

  • Functions returning pointers

    - by fg nu
    C++ noob here. I have a very basic question about a construct I found in the C++ book I am reading. // class declaration class CStr { char sData[256]; public: char* get(void); }; // implementation of the function char* CStr::get(void) { return sData; } So the Cstr::get function is obviously meant to return a character pointer, but the function is passing what looks like the value (return sData). Does C++ know to return the address of the returned object? My guess would have been that the function definition would be return &sData.

    Read the article

  • overriding implemented base class methods

    - by user793468
    I read somewhere that the chain of inheritance breaks when you alter a behavior from derived class. What does "altering a behavior" mean here? Is overriding an already implemented method in base class considered as "altering behavior"? Or, does the author mean altering method signatures and the output? Also, I ready Duplicating code is not a good practice, and its a maintenance nightmare. Again, does overriding an already implemented method in base class considered "Duplicating code"? If not, what would be considered as "Duplicating code"? I

    Read the article

< Previous Page | 47 48 49 50 51 52 53 54 55 56 57 58  | Next Page >