Questions tagged [state]
The state tag has no usage guidance.
116
questions
3
votes
2answers
198 views
Syntactic characterisation of extrinsic and intrinsic states
Gang of Four’s Flyweight design pattern introduces the concept of extrinsic and intrinsic state:
The key concept here is the distinction between intrinsic and extrinsic state. Intrinsic state is ...
2
votes
1answer
56 views
What is a good API design for different available actions per mutually-exclusive states?
I am implementing a entity that has multiple mutually-exclusive states. In each state, there are different set of actions (let's say, transitions) that may take the entity to a different state.
...
0
votes
2answers
101 views
Using UML State Machine for blockchain smart contract implementation
This is a conceptual question about applying UML State Machine model for smart contracts in blockchain.
I want to develop a smart contract framework in a bitcoin-like blockchain which is based on the ...
0
votes
0answers
11 views
Storing partial data in a redux store, how should be this done?
In my app I have some data to be fetched from the server (a list of recipes). In certain views, only a preview of the recipe is shown--this includes fields like title, rating, and an image of the ...
1
vote
0answers
47 views
How to avoid coupling of domain objects with UI data in a store-based Angular app?
The state of my TypeScript/Angular app contains objects from the UI layer and from the business domain layer. I'm exploring store-based solutions (eg ngrx, ngxs) to keep this state in memory.
As ...
0
votes
1answer
57 views
How to keep state alive between deployments
In our history, when we did a new release (deployment) any user who was "logged in" was logged out and that was obviously not ideal. Then I switched platform from a custom stack to a cloud provider ...
0
votes
0answers
28 views
Modelling device-oriented domain
My application is connected to several hardware devices, where as for each device, there is a dedicated device client containing it's own representation of the device protocol, response/request or ...
0
votes
0answers
29 views
State Management design
I am working a product which have
WebApi
Android/ios app
Web app
WebApi is hosted in AWS EC2 .
Currently we have requirement like we need to mantain state. Take one scenario. App have 4 pages. ...
9
votes
2answers
2k views
Stateful vs non-stateful app [closed]
I have been learning about stateful apps vs non-stateful, but I am still a bit confused on this topic.
For example, let's say I have an app running on Node where users are assigned to random rooms as ...
0
votes
2answers
309 views
Is the global state believed to be evil because of its nature or mostly due to its usual, no-rules usage?
I don't dislike global state, but that could be due to the lack of experience. I was thinking about what the usual implementation of global state is:
A big variable where data flows in a non-...
6
votes
1answer
333 views
Is it better to use lambda functions or boolean variables to record state
I have heard some people claiming that boolean state variables are generally bad and should be avoided when possible. Apparently in many cases it is possible to put state into lambda functions, ...
1
vote
1answer
119 views
Are “I'm writing android applications” and “follow open-closed principles” reasons to allow global state?
For example, suppose I have an android application, in simple, there are 3 activities :
MainActivity -> Main2Activity -> Main3Activity
,which user can visit them in sequence (eg: by button ...
1
vote
3answers
140 views
Is it ok to duplicate a program memory to avoid inline reset?
I have a time-critical function that needs to be executed multiple times sequentially.
void task(state_t *state);
It uses a relatively large amount of memory, so I figured that allocating it once ...
2
votes
1answer
64 views
How to restore to the correct state when the running process may get shut down thus missing some events?
Here are the requirements: (not the real case, just very simplied version)
There is some sort of promotion which lasts for a week.
The selected users who may benefit from the promotion is fixed at ...
0
votes
1answer
287 views
Angular 7 - Injecting a State/Context Snapshot
Requirement
There is some (for arguments sake) “global” application state that I am interested in injecting into components.
Each candidate component should receive an immutable snapshot of the ...
2
votes
3answers
222 views
Are cascading drop down lists an example of a need to keep application state?
If I have a page with three cascading dropdownlists, is that an example of controlling the state of a web application (assume it is part of a larger application)?
I want to make sure I understand ...
0
votes
1answer
94 views
Should I “Connect->To controller A”, or “To controller A->Connect”?
For example, suppose I have a shopping app, which has a user info page to show user info:
class UserInfoController{
toPurchaseRecord(){
}
}
and a purchase record page to show purchase record,...
3
votes
3answers
199 views
What to do when an aggregate is given a bad event?
What is usually done when an aggregate is asked to apply an "impossible" event to its state?
For example, if a ShoppingCart aggregate has already applied a CustomerAckRec (The customer has ...
5
votes
1answer
277 views
Is private global mutable state ever appropriate, namely when used to prevent API misuse?
I am writing a type checker for an ML dialect that involves generating "fresh" (new and unique) "type variables" (values representing unknowns). My strategy, and the strategy that seems to be used in ...
0
votes
0answers
157 views
Hierarchical state machine. Is there a term for the deepest nested state in a state configuration?
A flat state machine has one active state. In a hierarchical state machine (HSM), if the HSM is in a child state, it's also in it's parent state. So, an active state configuration of an HSM consists ...
2
votes
1answer
109 views
What's a clean way to manage state in Angular and have components update?
I'm using a service to manage state in Angular:
import { Injectable } from '@angular/core';
import { Subject } from 'rxjs';
@Injectable()
export class DrawingAreaService {
itemChange: Subject<...
1
vote
2answers
277 views
How to implement online/offline data synchronisation?
I want to create a desktop application.
The application must be able to accept database transactions even if internet connection is lost, but as soon as internet connection is available the ...
1
vote
3answers
2k views
Better to use Global Variable or Coroutine in general?
Is it better to store state in a global variable or in a coroutine, specifically in Python? I don't understand the best practice here.
For example, consider a simple Flask script:
from flask import ...
0
votes
1answer
251 views
How to avoid Global State with a world map?
This is a conceptual problem I'm having general difficulty with, and I'd like to look at an example that can hopefully help clarify this: using a map to represent an alterable game world. For ...
1
vote
0answers
29 views
React JS: Mixing data types for one state property
In the spirit of minimising state I always have a desire to mix data types for a given state property. For instance, if I were creating a React page that rendered a list of items that could either be ...
1
vote
1answer
322 views
Handling error in multiple state machines in embedded systems in C
I have few state machines which run "concurrently" in a super loop.
do
{
state_one();
state_two();
state_three();
/* The point I want to deal with the error */
} while(1);
Each of these ...
1
vote
1answer
113 views
What does it mean “state complects value and time”?
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 well.
Is ...
1
vote
1answer
342 views
How should I structure React Redux components when requesting Data From an API?
I have a search box I'm going to use on different pages (I use the term 'page' loosely here).
The search box puts its value (the search string) into the Redux state.
The results are populated from an ...
2
votes
2answers
93 views
3 tier application state handling
The objective of my application is to control and monitor sensor based equipment (temperature, humidity etc). Data from the equipments is transmitted using GSM, Ethernet or Serial port channels. When ...
6
votes
2answers
3k views
React: Nested object as state vs individual properties
Are there any use-cases where a nested object as state is either more optimal/easier to work with than individual properties?
For instance if I wanted to express some user controls for interacting ...
1
vote
2answers
544 views
What's the proper way to think about state monads?
I've been using a functional approach in my programming of late. I know that mutability and state changes are big no nos within the paradigm. I now find myself working with databases and other data ...
2
votes
2answers
347 views
Get value from UI element or from variable
I had a debate with a friend and I'm looking for a way to resolve it and decide which approach is better for maintenance and whether there's some consensus about a best practice regarding it:
If an ...
-2
votes
1answer
58 views
Single Page Apps: handling state dependencies
If I have an React/Redux single page application that has - say - a customers page that lists businesses that are customers, and from there each customer can be accessed with a URL like this:
/...
4
votes
3answers
167 views
Changing bot application state (Starting → Started → Stopping → Stopped)
I am developing a bot which I need to start and stop at will.
I have 2 buttons in my form, StartButton and StopButton which change the state.
The Bot has 4 possible states: starting, started, ...
0
votes
1answer
164 views
Using CSS classes to express state
Is it good practice to express the state of an HTML element--such as whether an input's value is valid--using a CSS class? Would it be better practice to use data attributes, the properties of a ...
0
votes
2answers
127 views
Techniques for observing runtime state in C
What are the techniques for C programs which allow easily inspecting the state of the embedded device, through a communication link?
For example, for a microcontroller device which communicates with ...
3
votes
4answers
3k views
Does object-oriented programming allows side effects and state changes?
I know that obviously every language has its own characteristics and implementations, but from a theoretical standing point, viewing OOP as an abstract programming paradigm, does it allows side ...
0
votes
1answer
198 views
Redux: When Should I Keep Track of State and When Should I Not?
NOTE: I am new with the whole concept of state management. I never got into the older languages that "explicitly used" states.
I dived into React and Redux for the past week, and as I'm getting into ...
-2
votes
1answer
322 views
HTML5/Canvas Graphics editor and Immutable state (EaselJS and Redux, ngrx/store)
This question is about the architecture approach.
How would someone go about creating the immutable state for a graphics editor that would eventually provide an "undo/redo" functionality, considering ...
12
votes
4answers
1k views
When programming in Functional style, do you have a single application state that you weave through the application logic?
How do I construct a system that has all of the following:
Using pure functions with immutable objects.
Only pass into a function data that the function it needs, no more (i.e. no big application ...
4
votes
2answers
104 views
How to to send a file and record that it has been sent in an atomic way?
I'm not sure how to best approach this problem. I've got an object in my local database, for example this one:
{ title: "my-object", uploaded: false }
I convert this to a file, say my-object.txt and ...
98
votes
8answers
39k views
How to keep applications stateless
This may be a convoluted question, but I'm trying to get a better understanding of statelessness.
Based on what I've read, web applications should be stateless, meaning each request is treated as an ...
3
votes
1answer
587 views
What is a (Redux) selector?
I am learning Redux (a JavaScript state container tool). I am finding numerous references to something called a "selector" (e.g. here, here, here, and here). However, I don't seem to be finding a ...
2
votes
1answer
369 views
Is global state evil if it doesn't change behavior?
I have a library in C where the API uses "objects" to interact with the application. These "objects" are opaque pointers that are created, destroyed, and modified via API calls.
These "objects" do ...
1
vote
1answer
180 views
Can I, Should I, How do I refactor for vuex - redux?
We need to get more much more rigorous about managing state in our business application. The heart of our problem is an object, lets call it an "TaxRefundApplication", that has about 20 properties, ...
7
votes
2answers
959 views
How to store and validate data between state transitions?
I'm developing a largeish application that will have custom finite state machines. That is, the admin users of the application will be able to create their own state machines, limited by little pieces ...
3
votes
1answer
272 views
UML “direct substate” vs “transitively nested substate”
I am reading through Wikipedia's page on UML state machines. I don't understand where it says:
A nested state is called a direct substate when it is not contained by
any other state; otherwise, ...
3
votes
2answers
990 views
State handling in WPF-MVVM
I am looking for advice on handling states in a WPF MVVM environment.
As an example, assume we have
A TreeView (or some other ItemsControl) with some items and
a button that is enabled when an item ...
0
votes
2answers
1k views
Using Static vs Passing Parameters
I'm implementing a state-pattern design in Java to calculate the current position of an object following a trapezoidal trajectory.
The pattern consists of a Context, State and states classes.
...
5
votes
3answers
4k views
Stateful vs stateless (non web app) applications
I would like to understand the difference between stateful and stateless applications.
What would be a non web app example of a python application which is
stateless vs stateful?
Would a script which ...
