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Questions tagged [immutability]

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Immutability is about having objects that cannot be changed.

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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 (...
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I'm quite confused about the concept of mutability (or mutation?), especially across different languages. In a language like Python: x = 10 x = 20 I believe this is called shadowing (or rebinding) ...
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Lombok is used in the legacy project where I am currently working for since last year. The project is legacy with 10+ years, and POJO/JavaBeans, i.e. @Data annotated classes, have been widely used for ...
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I have a Spring service that acts as an adapter for another service in my company. The service receives a request to generate push notifications for a given user and needs to call the other service ...
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Edit: I'm copying the question but changing the example code. Apparently, I used a bad example earlier that contained an imprue getter. I'm keeping the old example code at the bottom so the first ...
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At my org we extensively use @Value.Immutable annotation to generate Immutable classes (usually with builders) for our internal data transfer objects (DTOs). In our codebase I've seen both interfaces ...
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While I was learning functional programming I have encounterd two for me very similar terms: immutability and persistence. Also I have read simular questions from stackoverflow, but I am still ...
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Java never had immutable primitive arrays. However Java does have an immutable List or Map or other collection classes and of course final primitive fields and variables. In Java if you try to make an ...
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The most popular answer is - it is an object whose state does not change after creation. What does it actually mean? My understanding is that any method call on the object should give the same result. ...
kan's user avatar
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None of my team's programs care about multithreading, parallelisation, async, or anything else that benefit from immutability. However, immutability is clearly in fashion at the moment and I'm ...
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I am looking at the List<T>.AsReadOnly() method. Since List<T> itself is a IReadOnlyCollection<T>. (It implements IReadOnlyList<T> and IReadOnlyList<T> implements ...
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With Java record being immutable, I don't know how to use them properly in the context of something like a CRUD application. If we take a very simple example of a "Organization" record: ...
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I've heard people say things like "B can't inherit from A because A is immutable and B is mutable". My understanding of inheritance in Object-Oriented Programming is that you use it to add ...
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I am reading through "Clean Architecture: A Craftsman's Guide to Software Structure and Design" and it says that: All race conditions, deadlock conditions, and concurrent update problems are ...
Quantum Guy 123's user avatar
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Is it a good idea to mark a function const from clean code perspective if it change other objects' states? I'd like to know what is the experience with this or is it considered a bad practice for any ...
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I have a code that reads a YAML file that consists of several parameters whose values are used throughout the code. For clarity, the YAML file has the following structure: PARAM_1: value_1 PARAM_2: ...
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Which are the technical reasons/considerations for the sort() and reverse() JavaScript array methods to be in-place operations instead of returning a new array without modifying the original one, like ...
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I'm learning about immutability (specifically in C#) and I can't understand the examples out there stating that making an object immutable brings real benefits (besides a shared object in a multi ...
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So, I have an entity called Consultation that is being used as a member variable of the class VideoCallViewModel that goes like this: struct Consultation: Equatable { enum Status: Int, ...
Bawenang Rukmoko Pardian Putra's user avatar
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The title almost sums it up but let me be example-led and clearer. Assuming we have a class: class T: def goto(self, value): print('go') And a second inheriting class: class A(T): def ...
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I'm very new to writing immutable code. Would there be any fundamental issues trying to transpile arbitrary mutable code person.age = 20 into immutable code person = { ...person, age: 21 }? I am aware ...
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What is the intended usage of the ImmutableDictionary<TKey,TValue>.ValueComparer property? Why is it useful being able to compare dictionary values by using a specified equality semantic? I ...
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I feel this is a bad question because I probably do not understand what I am talking about. In my effort to learn about functional programming, I became stumped on understanding the idea of immutable ...
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If immutability is "good" and yet you can in effect change the value in an Integer or String variable (never mind that you get a new reference -- the value has changed) what good is it that ...
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I think the answer to the first part of my question is, "yes" -- no point in making objects immutable in a single-threaded application (or I guess in a multi-threaded application if that ...
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I have designed a simple objects validation framework in Java in the context of a code refactoring. The framework has a ValidationRule interface with one method Errors validate(MyObject myObject, ...
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I have the following code: const string endPoint = @"foo{0}?pageNum={1}&itemsPerPage={2}"; const int itemsPerPage = xxx; InvoiceCollection response = await _apiClient .GetAsync<...
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Encapsulation In object-oriented programming (OOP), encapsulation refers to the bundling of data with the methods that operate on that data, or the restricting of direct access to some of an ...
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In many OOP programming languages, types can be made co-, contra- or in- variant. Most (if not all of these languages) are able to let variables be mutated in place, i.e. they are not fully immutable ...
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I rewrote a very long method in which some data is queried from a database, based on info about a particular account, which is queried first. I split out the account info into an immutable inner ...
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I'm adding Immutable objects support to my Micro ORM called "Symbiotic" In the case of a create, I need to pass back a newly created version of the value passed in because the object is immutable and ...
Eric Schneider's user avatar
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I need to share some associative data between different parts of my application with two requirements: immutability (so read-only) safety against mispelling or unavailable index inside the data mixed ...
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I know there is no right and wrong answer here, I'm just looking for other opinions on who should handle immutability, dependency inversion and decoupling. Example 1: Here each function caller has ...
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I'm all on board with functional programming in Javascript - particularly within the context of using React and Redux. Something that I've been running into again and again, is how easy it is to ...
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Immutable objects In object-oriented and functional programming, an immutable object (unchangeable[1] object) is an object whose state cannot be modified after it is created Wikipedia (https://...
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I am from OO background just started learning FP paradigm. Came across quote by Michael Feathers - "OO makes code understandable by encapsulating moving parts. FP makes code understandable by ...
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Generally, constructors in an interface are considered as being an anti-pattern. Some languages even don't allow that. Then I don't understand how we're supposed to deal with polymorphic immutable ...
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I would like to be able to implement immutable data in C++. In short, given a C++ object in which I would like to modify a member variable, instead of modifying that member in place I would like to ...
Rulle's user avatar
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I'm implementing a Redux store for a React app using redux-saga for API calls. I've used Immutable.js before for other Redux-using React apps but the nature of previous projects always evidently ...
timbo's user avatar
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The blockchain stores basically an immutable permanent record of every transaction. This means the data is constantly increasing. Wondering if one has a model for easily roughly estimating data usage. ...
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I have seen examples where even though the object is immutable there are situations in which we need to update some fields and as I understand it, the object is passed to a constructor which makes a ...
Jeff's user avatar
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In C#, i can declare an immutable field on a class using readonly. This works for value types, but if its a reference type, there is nothing stopping me calling methods on the object to change its ...
richzilla's user avatar
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Trying to see if immutability is a good fit for highly dynamic objects like game entities (that constantly are moving around and changing) or particle systems, each which might have thousands or ...
Lance Pollard's user avatar
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I can see the benefits of mutable vs immutable objects like immutable objects take away lot of hard to troubleshoot issues in multi threaded programming due to shared and writeable state. On the ...
rahulaga-msft's user avatar
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Say I have an interface Interface, which only contains getters for various fields. This interface has multiple implementations (say Foo and Bar), each of which adds various fields. All these ...
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I'm rewatching Rich Hickey great talk "Simple Made Easy" And around min 35:40 when talking about state, mentions that State complects value and time, but I'm not sure I'm understanding this ...
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I have an interface with only a single method that could be replaced by java.util.function.Function from the JDK: interface DataModel { boolean apply(Map<String, Integer> input); } The ...
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Recently, I worked on an Android project with Kotlin. As an architecture, there were immutable data classes and functions (not methods which are members of a class), where the functions generate new ...
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I was reading on this software engineering page about the use of static methods. However, I'm confused, and maybe it's about the context in which it talks about static. The idea is, that static is ...
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I have been increasingly using immutable data storing for my web-app, due to some advantages it has (simpler writes, ability to view history / activity). I am doing it using MySQL dabatases, simply ...
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