Search Results

Search found 256 results on 11 pages for 'superclass'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 3/11 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11  | Next Page >

  • Perl - Calling subclass constructor from superclass (OO)

    - by Emmel
    This may turn out to be an embarrassingly stupid question, but better than potentially creating embarrassingly stupid code. :-) This is an OO design question, really. Let's say I have an object class 'Foos' that represents a set of dynamic configuration elements, which are obtained by querying a command on disk, 'mycrazyfoos -getconfig'. Let's say that there are two categories of behavior that I want 'Foos' objects to have: Existing ones: one is, query ones that exist in the command output I just mentioned (/usr/bin/mycrazyfoos -getconfig`. Make modifications to existing ones via shelling out commands. Create new ones that don't exist; new 'crazyfoos', using a complex set of /usr/bin/mycrazyfoos commands and parameters. Here I'm not really just querying, but actually running a bunch of system() commands. Affecting changes. Here's my class structure: Foos.pm package Foos, which has a new($hashref-{name = 'myfooname',) constructor that takes a 'crazyfoo NAME' and then queries the existence of that NAME to see if it already exists (by shelling out and running the mycrazyfoos command above). If that crazyfoo already exists, return a Foos::Existing object. Any changes to this object requires shelling out, running commands and getting confirmation that everything ran okay. If this is the way to go, then the new() constructor needs to have a test to see which subclass constructor to use (if that even makes sense in this context). Here are the subclasses: Foos/Existing.pm As mentioned above, this is for when a Foos object already exists. Foos/Pending.pm This is an object that will be created if, in the above, the 'crazyfoo NAME' doesn't actually exist. In this case, the new() constructor above will be checked for additional parameters, and it will go ahead and, when called using -create() shell out using system() and create a new object... possibly returning an 'Existing' one... OR As I type this out, I am realizing it is perhaps it's better to have a single: (an alternative arrangement) Foos class, that has a -new() that takes just a name -create() that takes additional creation parameters -delete(), -change() and other params that affect ones that exist; that will have to just be checked dynamically. So here we are, two main directions to go with this. I'm curious which would be the more intelligent way to go.

    Read the article

  • Returning superclass of return type from remote EJB method

    - by fish
    Let's say I have remote interface A: @Remote public interface A { public Response doSomething(); } And implementation: @Stateless public class B implements A { public BeeResponse doSomething() {...} } Where: BeeResponse extends Response. Response is located in the EJB-API jar and BeeResponse is in the implementation jar. Response and BeeResponse have different serialVersionUID. My assumption is that the unmarshalling of the response from B will fail, am I correct?

    Read the article

  • Retrieve only the superclass from a class hierarchy

    - by user1792724
    I have an scenario as the following: @Entity @Table(name = "ANIMAL") @Inheritance(strategy = InheritanceType.JOINED) public class Animal implements Serializable { @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "S_ANIMAL") @SequenceGenerator(name = "S_ANIMAL", sequenceName = "S_ANIMAL", allocationSize = 1) public int getNumero() { return numero; } public void setNumero(int numero) { this.numero = numero; } . . . } and as the subclass: @Entity @Table(name = "DOG") public class Dog extends Animal { private static final long serialVersionUID = -7341592543130659641L; . . . } I have a JPA Select statement like this: SELECT a FROM Animal a; I'm using Hibernate 3.3.1 As I can see the framework retrieves instances of Animal and also of Dog using a left outer join. Is there a way to Select only the "part" Animal? I mean, the previous Select will get all the Animals, those that are only Animals but not Dogs and those that are Dogs. I want them all, but in the case of Dogs I want to only retrieve the "Animal part" of them. I found the @org.hibernate.annotations.Entity(polymorphism = PolymorphismType.EXPLICIT) but as I could see this only works if Animal isn't an @Entity. Thanks a lot.

    Read the article

  • why the class of subclass is superclass

    - by Raj
    def singleton_class class << self self end end end class Human proc = lambda { puts 'proc says my class is ' + self.name.to_s } singleton_class.instance_eval do define_method(:lab) do proc.call end end end class Developer < Human end Human.lab # class is Human Developer.lab # class is Human ; oops Why Developer.lab is reporting that it is Human ?

    Read the article

  • Instance_eval: why the class of subclass is superclass

    - by Raj
    def singleton_class class << self self end end class Human proc = lambda { puts 'proc says my class is ' + self.name.to_s } singleton_class.instance_eval do define_method(:lab) do proc.call end end end class Developer < Human end Human.lab # class is Human Developer.lab # class is Human ; oops Following solution works. def singleton_class class << self self end end class Human proc = lambda { puts 'proc says my class is ' + self.name.to_s } singleton_class.instance_eval do define_method(:lab) do self.instance_eval &proc end end end class Developer < Human end Human.lab # class is Human Developer.lab # class is Human ; oops Why Developer.lab is reporting that it is Human ? And what can be done so that proc reports Developer when Developer.lab is invoked.

    Read the article

  • Java: Reflection against casting when you know superclass

    - by Ema
    I don't know exactly how to define my doubt so please be patient if the question has already been asked. Let's say I have to dinamically instantiate an object. This object will surely be instance of a subclass of a known, immutable class A. I can obtain dinamically the specific implementation class. Would it be better to use reflection exactly as if I didn't know anything about the target class, or would it be preferrable/possible to do something like: A obj = (Class.forName("com.package.Sub-A")) new A(); where Sub-A extends A ? The purpose would be to avoid reflection overhead times... Thank you in advance.

    Read the article

  • About calling an subclass' overriding method when casted to its superclass

    - by Omega
    #include <iostream> class Vehicle { public: void greet() { std::cout << "Hello, I'm a vehicle"; } }; class Car : public Vehicle { public: void greet() { std::cout << "Hello, I'm a car"; } }; class Bike : public Vehicle { public: void greet() { std::cout << "Hello, I'm a bike"; } }; void receiveVehicle(Vehicle vehicle) { vehicle.greet(); } int main() { receiveVehicle(Car()); return 0; } As you can see, I'm trying to send a parameter of type Vehicle to a function, which calls greet(). Car and Bike are subclasses of Vehicle. They overwrite greet(). However, I'm getting "Hello, I'm a vehicle". I suppose that this is because receiveVehicle receives a parameter of type Vehicle instead of a specific subclass like Car or Bike. But that's what I want: I want this function to work with any subclass of Vehicle. Why am I not getting the expected output?

    Read the article

  • Matching the superclass's constructor's parameter list, is treating a null default value as a non-null value within a constructor a violation of LSP?

    - by Panzercrisis
    I kind of ran into this when messing around with FlashPunk, and I'm going to use it as an example. Essentially the main sprite class is pretty much class Entity. Entity's constructor has four parameters, each with a default value. One of them is graphic, whose default value is null. Entity is designed to be inherited from, with many such subclasses providing their own graphic within their own internal workings. Normally these subclasses would not have graphic in their constructor's parameter lists, but would simply pick something internally and go with it. However I was looking into possibly still adhering to the Liskov Substitution Principal. Which led me to the following example: package com.blank.graphics { import net.flashpunk.*; import net.flashpunk.graphics.Image; public class SpaceGraphic extends Entity { [Embed(source = "../../../../../../assets/spaces/blank.png")] private const BLANK_SPACE:Class; public function SpaceGraphic(x:Number = 0, y:Number = 0, graphic:Graphic = null, mask:Mask = null) { super(x, y, graphic, mask); if (!graphic) { this.graphic = new Image(BLANK_SPACE); } } } } Alright, so now there's a parameter list in the constructor that perfectly matches the one in the super class's constructor. But if the default value for graphic is used, it'll exhibit two different behaviors, depending on whether you're using the subclass or the superclass. In the superclass, there won't be a graphic, but in the subclass, it'll choose the default graphic. Is this a violation of the Liskov Substitution Principal? Does the fact that subclasses are almost intended to use different parameter lists have any bearing on this? Would minimizing the parameter list violate it in a case like this? Thanks.

    Read the article

  • How do I prevent JAXB from binding superclass methods of the @XmlRootElement when marshalling?

    - by Matt Fisher
    I have a class that is annotated as the @XmlRootElement with @XmlAccessorType(XmlAccessType.NONE). The problem that I am having is that the superclass's methods are being bound, when I do not want them to be bound, and cannot update the class. I am hoping there is an annotation that I can put on the root element class to prevent this from happening. Example: @XmlRootElement @XmlAccessorType(XmlAccessType.NONE) public class Person extends NamedObject { @XmlElement public String getId() { ... } } I would expect that only the methods annotated @XmlElement on Person would be bound and marshalled, but the superclass's methods are all being bound, as well. The resulting XML then has too much information. How do I prevent the superclass's methods from being bound without having to annotate the superclass, itself?

    Read the article

  • Use super class's address/pointer in initialization list

    - by JQ
    context 1: class D : public B1, public B2{}; context 2: B2 takes B1 to initialize: B2( B1 * ) //B2's constructor my question is in D's initialization list: D::D() : B1(), B2( ? )... What should be in ? I don't want to put " (B1*)this " in the ? place, because it's no good to use "this" in initialization list. And since B1 part has been initialized, it makes sense to use it. What should I do ?

    Read the article

  • Use Automapper to flatten sub-class of property

    - by Neil
    Given the classes: public class Person { public string Name { get; set; } } public class Student : Person { public int StudentId { get; set; } } public class Source { public Person Person { get; set; } } public class Dest { public string PersonName { get; set; } public int? PersonStudentId { get; set; } } I want to use Automapper to map Source - Dest. This test obviously fails: Mapper.CreateMap<Source, Dest>(); var source = new Source() { Person = new Student(){ Name = "J", StudentId = 5 }}; var dest = Mapper.Map<Source, Dest>(source); Assert.AreEqual(5, dest.PersonStudentId); What would be the best approach to mapping this given that "Person" is actually a heavily used data-type throughout our domain model.

    Read the article

  • why Cannot invoke super constructor from enum constructor ?

    - by hilal
    public enum A { A(1); private A(int i){ } private A(){ super(); // compile - error // Cannot invoke super constructor from enum constructor A() } } and here is the hierarchy of enum A extends from abstract java.lang.Enum extends java.lang.Object Class c = Class.forName("/*path*/.A"); System.out.println(c.getSuperclass().getName()); System.out.println(Modifier.toString(c.getSuperclass().getModifiers()).contains("abstract")); System.out.println(c.getSuperclass().getSuperclass().getName());

    Read the article

  • inheritance problem OOP extend

    - by hsmit
    If a Father is a Parent and a Parent is a Person and a Person has a Father I create the following: class Person{ Father father; } class Parent extends Person{} class Father extends Parent{} Instances: Person p1 = new Person(); Person p2 = new Person(); p1.father = p2; //father is of the type Father This doesn't work... Now try casting:: Person p1 = new Person(); Person p2 = new Person(); p1.father = (Father)p2; This doesn't work either. What does work for this case?

    Read the article

  • What's my best approach on this simple hierarchy Java Problem?

    - by Nazgulled
    First, I'm sorry for the question title but I can't think of a better one to describe my problem. Feel free to change it :) Let's say I have this abstract class Box which implements a couple of constructors, methods and whatever on some private variables. Then I have a couple of sub classes like BoxA and BoxB. Both of these implement extra things. Now I have another abstract class Shape and a few sub classes like Square and Circle. For both BoxA and BoxB I need to have a list of Shape objects but I need to make sure that only Square objects go into BoxA's list and only Circle objects go into BoxB's list. For that list (on each box), I need to have a get() and set() method and also a addShape() and removeShape() methods. Another important thing to know is that for each box created, either BoxA or BoxB, each respectively Shape list is exactly the same. Let's say I create a list of Square's named ls and two BoxA objects named boxA1 and boxA2. No matter what, both boxA1 and boxA2 must have the same ls list. This is my idea: public abstract class Box { // private instance variables public Box() { // constructor stuff } // public instance methods } public class BoxA extends Box { // private instance variables private static List<Shape> list; public BoxA() { // constructor stuff } // public instance methods public static List<Square> getList() { List<Square> aux = new ArrayList<Square>(); for(Square s : list.values()) { aux.add(s.clone()); // I know what I'm doing with this clone, don't worry about it } return aux; } public static void setList(List<Square> newList) { list = new ArrayList<Square>(newList); } public static void addShape(Square s) { list.add(s); } public static void removeShape(Square s) { list.remove(list.indexOf(s)); } } As the list needs to be the same for that type of object, I declared as static and all methods that work with that list are also static. Now, for BoxB the class would be almost the same regarding the list stuff. I would only replace Square by Triangle and the problem was solved. So, for each BoxA object created, the list would be only one and the same for each BoxB object created, but a different type of list of course. So, what's my problem you ask? Well, I don't like the code... The getList(), setList(), addShape() and removeShape() methods are basically repeated for BoxA and BoxB, only the type of the objects that the list will hold is different. I can't think of way to do it in the super class Box instead. Doing it statically too, using Shape instead of Square and Triangle, wouldn't work because the list would be only one and I need it to be only one but for each sub class of Box. How could I do this differently and better? P.S: I could not describe my real example because I don't know the correct words in English for the stuff I'm doing, so I just used a box and shapes example, but it's basically the same.

    Read the article

  • Use of Java [Interfaces / Abstract classes]

    - by Samuel
    Hello, Lately i decided to take a look at Java so i am still pretty new to it and also to the approach of OO programming, so i wanted to get some things straight before learning more, (i guess it's never to soon to start with good practices). I am programming a little 2D game for now but i think my question applies to any non trivial project. For the simplicity i'll provide examples from my game. I have different kinds of zombies, but they all have the same attributes (x, y, health, attack etc) so i wrote an interface Zombie which i implement by WalkingZombie, RunningZombie TeleportingZombie etc. Is this the best thing to do? Am i better of with an abstract class? Or with a super class? (I am not planning to partially implement functions - therefor my choice for an interface instead of an abstract class) I have one class describing the main character (Survivor) and since it is pretty big i wanted to write an interface with the different functions, so that i can easily see and share the structure of it. Is it good practice? Or is it simply a waste of space and time? I hope this question will not be rated as subjective because i thought that experienced programmers won't disagree about this kind of topic since the use of interfaces / super classes / abstract classes follows logical rules and is thereby not simply a personal choice. Thank you for your time -Samuel

    Read the article

  • How to use composition from another class to set Name?

    - by user1874549
    I have some of the code here. I am trying to use one class to reference another so I may obtain the first name of the person. I want the firstName in main class to work but IDE mentions the variable isn't found. Will replacing 'first' with 'firstName' work? Main class: public BasePlusCommissionEmployee( String first, String last, String ssn, double sales, double rate, double salary) { cE = new CommissionEmployee( first, last, ssn, sales, rate ); setBaseSalary( salary ); } public void setFirstName(String firstName) { // Trying to get this to work... cE.setFirstName(first); } SubClass: private String firstName; public void setFirstName( String first ) { firstName = first; }

    Read the article

  • LiveView plugin template creates lots of errors?

    - by Shedo Surashu
    I'm trying to get the LiveView plugin template to work but upon import of the project into Eclipse, I already have 13 errors and 2 warnings. I have already downloaded SDK for Android 1.6 which I believe is what it requires. The errors are as follows: The method startPlugin() of type AbstractPluginService.LiveViewCallback must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 173 Java Problem The method stopPlugin() of type AbstractPluginService.LiveViewCallback must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 182 Java Problem The method onSharedPreferenceChanged(SharedPreferences, String) of type new SharedPreferences.OnSharedPreferenceChangeListener(){} must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 360 Java Problem The method onServiceDisconnected(ComponentName) of type new ServiceConnection(){} must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 345 Java Problem The method onServiceConnected(ComponentName, IBinder) of type new ServiceConnection(){} must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 318 Java Problem The method screenMode(int) of type AbstractPluginService.LiveViewCallback must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 230 Java Problem The method openInPhone(String) of type AbstractPluginService.LiveViewCallback must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 221 Java Problem The method run() of type SandboxPluginService.Rotator must override a superclass method SandboxPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins/sandbox line 254 Java Problem The method onUnregistered() of type AbstractPluginService.LiveViewCallback must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 216 Java Problem The method run() of type SandboxPluginService.Timer must override a superclass method SandboxPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins/sandbox line 235 Java Problem The method displayCaps(int, int) of type AbstractPluginService.LiveViewCallback must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 206 Java Problem The method button(String, boolean, boolean) of type AbstractPluginService.LiveViewCallback must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 196 Java Problem The method getPluginName() of type AbstractPluginService.LiveViewCallback must override a superclass method AbstractPluginService.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/src/com/sonyericsson/extras/liveview/plugins line 191 Java Problem and the warnings: The method getInterfaceDescriptor() from the type IPluginServiceV1.Stub.Proxy is never used locally IPluginServiceV1.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/gen/com/sonyericsson/extras/liveview line 242 Java Problem The method getInterfaceDescriptor() from the type IPluginServiceCallbackV1.Stub.Proxy is never used locally IPluginServiceCallbackV1.java /com.sonyericsson.extras.liveview.plugins.PluginPreferences/gen/com/sonyericsson/extras/liveview line 130 Java Problem These all occur fresh from the ZIP file from Sony Mobile's Developer World. No code has been changed. Any thoughts?

    Read the article

  • Should I implement an interface directly or have the superclass do it?

    - by c_maker
    Is there a difference between public class A extends AbstractB implements C {...} versus... public class A extends AbstractB {...} AbstractB implements C {...} I understand that in both cases, class A will end up conforming to the interface. In the second case, AbstractB can provide implementation for interface methods in C. Is that the only difference? If I do NOT want to provide an implementation for any of the interface methods in AbstractB, which style should I be using? Does using one or the other have some hidden 'documentation' purpose?

    Read the article

  • JPanel superclass doesn't add the components of its subclasses..

    - by Acryl
    Well, I use a JFrame that adds two JPanels. Those JPanels are superclasses, because I find it easier to separate different areas of the GUI into different classes. But here's the problem: I add the (superclass) JPanel to the JFrame I set the layout of the superclass JPanel to new BorderLayout(); I add components in the subclasses, like this: JPanel panel = new JPanel(); panel.setLayout(new GridLayout(2,1)); panel.add(new JLabel("Label:"); panel.add(new JTextField(); add(panel, BorderLayout.NORTH); But it doesn't show. What do I do wrong? I've tried it without an additional JPanel in the subclasses, but it doesn't work either. I use jdk 1.6

    Read the article

  • Inheritance of closure objects and overriding of methods

    - by bobikk
    I need to extend a class, which is encapsulated in a closure. This base class is following: var PageController = (function(){ // private static variable var _current_view; return function(request, new_view) { ... // priveleged public function, which has access to the _current_view this.execute = function() { alert("PageController::execute"); } } })(); Inheritance is realised using the following function: function extend(subClass, superClass){ var F = function(){ }; F.prototype = superClass.prototype; subClass.prototype = new F(); subClass.prototype.constructor = subClass; subClass.superclass = superClass.prototype; StartController.cache = ''; if (superClass.prototype.constructor == Object.prototype.constructor) { superClass.prototype.constructor = superClass; } } I subclass the PageController: var StartController = function(request){ // calling the constructor of the super class StartController.superclass.constructor.call(this, request, 'start-view'); } // extending the objects extend(StartController, PageController); // overriding the PageController::execute StartController.prototype.execute = function() { alert('StartController::execute'); } Inheritance is working. I can call every PageController's method from StartController's instance. However, method overriding doesn't work: var startCont = new StartController(); startCont.execute(); alerts "PageController::execute". How should I override this method?

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11  | Next Page >