Questions tagged [instance]
An instance is a particular occurrence of an object during the time when a computer program is running.
21 questions
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Are there any good and modern approaches, to have variables that feel global (no need to pass them around explicitly), yet are local to an instance?
I'm developing a library in JavaScript (TypeScript, actually) which is split into several modules. It's meant to run both on the web and in non-web environments like Node.js.
The library is meant to ...
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4
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2
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Should I expose an instance's state with methods?
I've read somewhere about a pattern that is as follows: if it'll change the state of the instance, the method should be named with a verb and return void; and if the method just returns something (...
2
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2
answers
223
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If an object x is an instance of a type T, then what is a type T for a concept C?
In concept-based programming (as in C++ concepts), I am wondering if there is a noun to say that:
A type T is an XXXX of a concept C.
in the same way we can say that:
An object x is an instance of ...
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-1
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1
answer
432
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Data sharing on a multi-instance application
I would like to know which architecture is more suitable when considering data sharing between tenants: a Multi-instance (Single-tenant) or Multi-tenant architecture with a database by tenant.
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2
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3
answers
259
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Are Instanced APIs a Problem in a C Interface?
So an Instanced API is one that behaves like an object. So for example:
foo* GetInstancedAPI();
void MemFuncSetter(foo* fooThis, const int arg);
int MemFuncGetter(const foo* fooThis) const;
This is ...
- 169
0
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1
answer
110
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Identifying the use case for instantiation only through existing instances
I was in my CS class when my instructor presented me the following classes:
public class UninstantiableTest {
private static Uninstantiable uninstantiable;
public static void ...
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0
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2
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850
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Does anonymous object instantiation have advantages over static object creation in this specific case?
In a Java program which I did not made and cannot change, only write extensions for it, the design forces me to create an object which will never be garbage collected. I tested and I can do it through ...
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5
answers
5k
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Why do we need instance variable in object oriented programming?
I've been teaching myself Object Oriented Programming(Ruby) for a while. However, I still don't quite understand some of its core principles, specifically, instance variable. Could somebody please ...
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1
vote
1
answer
65
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How to avoid fetching additional informations when instantiating objects
I'm creating an HTML5 game using javascript and have got some problems during the first instantiation of the objects of the scene.
Scenario
Self-written 2d game engine that supports multiple types ...
user242937
-1
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1
answer
177
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How to force user to create new instance of object
I have library with asynchronous thread and application who use them. Application can pass object to library of type provide by library interface. If application does not create new instance of object ...
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7
votes
1
answer
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Log4j logger per class vs logger per application
I am stuck at understanding a concept related to Logger creation, especially in the context of Java EE.
In my experience, I nearly always used one logger per application, with few cases when I needed ...
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0
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0
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65
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What happens to super handler with instance variables
What will happen if I extend a class A to a controller B, when A has instance variables (private, protected)?
I have a main controller MY_Controller(handler) which has several methods: can_modify (...
- 109
2
votes
2
answers
778
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Python OO problem
I started learning Python yesterday and I ran into a problem. I like to hear some thoughts on it.
As an exercise, I decided to build a chatserver. As part of the exercise, I wanted to write some ...
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15
votes
4
answers
5k
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Singleton or instantiate everytime I use? [duplicate]
I use a class that just extracts data from one known object, and distributes it to other known objects. No persistent configuration or such is needed in that class instance.
How should I decide ...
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22
votes
4
answers
239k
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What are the differences between class variables and instance variables in Java? [closed]
I'm very new to Java and want to understand the difference between class variables and instance variables.
For example:
class Bicycle {
static int cadence = 0;
int speed = 0;
int gear ...
- 433
2
votes
2
answers
580
views
Objects or primitives as arguments
I have come across the term "garbage disposal" and now I'm worried about using up too much memory. Apparently (correct me if I'm wrong) every time an object is created, memory is reserved for it, and ...
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vote
5
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Understanding basics of object declaration in Java
Is there a case when an object is declared without a call to the constructor?
as in, for example:
ArrayList<Integer> grades;
Or is it always the case that ArrayList<Integer> grades (as ...
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1
vote
2
answers
2k
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Instantiating objects in Java [closed]
I'm learning now Java from scratch and when I started to learn about instantiating objects, I don't understand - in which cases do I need to instantiate objects?
For example I'm studying from TutsPlus ...
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3
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4
answers
641
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Why are inheritance and interfaces restricted to instance members?
Disclaimer: I think the rules are almost the same in most OO languages, but since I'm most familiar with C# I'll be relating to this specific language.
I think that the use of attributes and ...
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2
votes
2
answers
1k
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observer class as instance
Sometimes I read in observer-pattern descriptions, to make the constructor of a observer base class protected so the class will be abstract. but by making the constructor public (if even one is ...
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4
answers
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Make methods that do not depend on instance fields, static?
Recently I started programming in Groovy for a integration testing framework, for a Java project. I use Intellij IDEA with Groovy plug-in and I am surprised to see as a warning for all the methods ...
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