Questions tagged [finite-state-machine]
The finite-state-machine tag has no usage guidance.
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Converting monolithic application to microservice architecture with sagas
I'm looking for architectural guidance.
I've got this monolithic application. It has a payment platform functionality, where payments are made, scheduled or on demand, via some banking API.
Payments ...
3
votes
2answers
238 views
Is rebooting a server idempotent or not?
In his article RESTful Casuistry, Tim Bray claims that rebooting a server is not idempotent:
But I don’t buy it, and here’s why. If I want to update some fields in an existing resource, I’m inclined ...
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1answer
64 views
Is there a name for this kind of state machine?
I'm thinking of a GUI architecture that works like a finite-state machine where there is a set of possible states and a set of possible inputs--or events.
The thing is, some states transition to the ...
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1answer
69 views
Scaffold design pattern [duplicate]
I'm looking for something that might be described as a "Scaffold design pattern".
I'm in the process of resurrecting an old piece of working but very buggy code that implements a Finite ...
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1answer
96 views
How to avoid repeating same states in a finite state machine implementation?
I have been implementing a finite state machine which basically ensures configuration of the external chip which communicates with my MCU via I2C. The skeleton of the configuration state machine looks ...
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2answers
74 views
Identifying states when using state machine to validate a form field
Scenario is simple, a password field with few validation rules.
The states I came up with are
default ( when the form loads or reset button is pressed)
filled ( should this even be a state ?)
valid ( ...
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1answer
88 views
oval of FSM diagram represent what?
I am reading a document of Varnish and I get the important VCL state image shown below.
We know we often use UML as a standard to draw a state machine.
but this image is not, is it follow another ...
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votes
1answer
88 views
What's the best way to design a state machine with different object inheritance
I have a class A and class B, both derive from the same parent class. Each object has a state machine inside it that defines it's behaviour. The behaviour is different though depending on if the ...
0
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2answers
85 views
FSM diagrams - Modern device with battery / charger
I'm studying state machines diagrams and was asked to come up with a diagram for a device that turns on and off when a button is pressed... but as with other modern devices nowadays, it can operate ...
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4answers
119 views
Documentation of Finite State Machine / Workflow
In my database, I store task data (id, timestamp, input data), and information about the state of the multi-step processing (e.g. prepare, execute, summarize). The program moves from one state to ...
2
votes
1answer
61 views
State Pattern: duplication in State and Context
Wikipedia gave an example of State Pattern:
Define LowerCaseState and MultipleUpperCaseState, both inherite from State.
interface State {
void writeName(StateContext context, String name);
}
...
4
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1answer
216 views
Repeating a state in a state machine
I have a state machine in which I might have to restart something when needed (Say restart a hardware). But after restarting, I need to run some tests on the thing. If the tests fail, I need to stop ...
2
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1answer
141 views
State Machine: what object is responsible for state transfer?
I would like to create a state machine.
Each State would have its run method, and, according to some logic would then set a next state.
Option 1:
If each state is responsible for determining a next ...
0
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1answer
169 views
Edit and extract the response of a system from its State machine diagram
Consider the following state machine diagram:
If we have the following event sequence :
Close door --> Start --> Open door --> Reset
and we need to know the corresponding response ...
3
votes
2answers
161 views
In an UML 2.5 State Machine, how can I model sending a Signal as an effect on a transition in a convenient way?
In an UML 2.5 State Machine, how can I model sending a Signal as an effect on a transition in a convenient way?
In one of the older UML versions you simply prefixed the name of the signal with a send ...
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0answers
53 views
Tiered/grouped/layered FSM for deisning software?
Well in the past during education about integrated systems we've been thought a lot about FSM and how to design those. It was a good tool to "talk" about complicated systems and create a common ...
0
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1answer
315 views
How to plot a state machine diagram of multiple related objects in one diagram?
In an order management system for example, what's the best way to plot the states of different objects that overlap and interconnect at different states?
Example:
Order object will have states like ...
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2answers
217 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 ...
8
votes
1answer
304 views
How to design a good generic tiled image downloader?
Tiled images
Tiled images are large images that have been split in smaller square tiles.
There are several tiled image formats, with different ways of organizing
the tile files.
A tiled image on ...
3
votes
2answers
204 views
Designing a builder as a compile-time state machine
I'm working on a text GUI library which comes with builders for UI components (Buttons, Panels, etc). I have a base class for these builders which I'd like to redesign so that meaningless component ...
2
votes
1answer
140 views
What is a good technique to process an event stream to ensure sequential or transactional consistency
I am trying to improve an event-driven processing system, which is having a few problems because the events are not guaranteed to arrive in the correct chronological sequence. This is due to batching ...
2
votes
2answers
250 views
Hierarchical State Machine (HSM) superstate and substate sharing event
I am learning HSMs and I can see a problem that I don’t know how to address. The problem is shown in the image bellow.
Inside S1, substates S11 and S12 are continuously changing in reaction to ...
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230 views
Linear “steps” of operations considered a state machine?
I have a set of tasks I perform to complete some larger operation. These tasks must be executed in linear order, and you cannot proceed onto the next task until the previous completes. For the most ...
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1answer
396 views
Problem in creating a correct finite-state-machine for a given short text
I like to create a finite-state machine for the given text below. While solving this, I came accross with several problems I listed at the bottom. (This example is in terms of testing (where you later ...
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Byzantine Failures - Client Voter and Replica on Same Processor
I need help understanding the following text from section 4.2 on this paper: Implementing Fault-Tolerant Services Using the State Machine
Approach: A Tutorial
Dependent-Failures Output ...
0
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1answer
178 views
Will FSM be a good solution?
At work, we are creating an android app. We have a business logic module for talking to an API for CRUD operations. The app I'm working on, the UI module, speaks to the business logic module to create,...
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2answers
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Can a state machine transition depend on the previous state?
I was wondering what the state machine for a video player would be like.
I can think of two states : playing and paused.
When the video is playing and the user clicks on a point in the progress ...
2
votes
1answer
2k views
What is the relationship between event driven design and state machines/charts?
I'm trying to understand event driven design better and have not picked up a book on it yet. But just from others explaining it to me it seems to be really similar to state machines/charts. What are ...
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2answers
159 views
How to handle state of an object? And how to enrich the state transition logic?
I am designing a class that has a state. I wonder if I should expose that state in the interface in view of allowing a decorator to enrich the state transition logic.
Shall my design expose access to ...
0
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2answers
553 views
If a business's workflow steps can reside solely in a database, is there a reason to use a workflow engine to accomplish those steps?
I found various libraries in C#, PHP, Python, etc. for workflows. By workflow I mean something like an employee wants personal time and that request starts with the employee and finishes in some ...
4
votes
2answers
356 views
Why do I need a game loop with states, instead of init the next state in current state directly?
For example, it is common to see games with game loop and states:
stateChanged(){
switch(state){
STATE.PLAYER_SELECT_CHARACTER:
this.currentController=new PlayerSelectCharacterController()...
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269 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 ...
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171 views
Can my state machines use state that is derived from model data?
I'm putting together some ideas and personal conventions on how to configure state machines when using a language specific library.
Because I'm adding state machines to existing model classes in my ...
2
votes
1answer
75 views
Using state machines when managing remote resources
So I’ve got a service I’m trying to clean up. It responds to requests by starting a stopped server on Amazon EC2, waiting for it to come online, then configures a 3rd party piece of software on the ...
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1answer
366 views
Finite State Machine odd number of bc at the end
I had this question in a school test:
Design a non-deterministic FSM that receives all words over {a,b,c} that:
Start with cc.
Contain at least 1 ab or aca.
Ends with an odd number of (bc).
The FSM ...
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vote
1answer
472 views
Why are next-state function and output functions of an FSM combinational functions?
From my understanding, combinational logic is dependent solely on input, and sequential logic involves state--memory.
When explaining a finite state machine (FSM), however, it is said that an FSM ...
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4answers
6k views
So what exactly is a final state of a finite state machine?
I am playing around the state machine concept trying to better understand the best areas of their application. The formal definition of an FSM contains the following elements:
finite non-empty set of ...
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1answer
3k views
Finite State Vending Machine Diagram
In class, we are asked to draw a finite state machine with the following instructions:
Design a finite state machine to model a vending machine that accepts
only quarters and gives a container of ...
2
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1answer
3k views
State machine with database records
I was re-learning about state diagrams this weekend, and realized that I may have been using them for years without realizing it.
Suppose i have an order record, with a bunch of fields including ...
2
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2answers
329 views
How to model a statemachine in this case
I have a system where lot of messages come and go over network, each message to be sent or received goes through several states, state change occurs based on external events for example if the linked ...
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0answers
51 views
How do I know the depth of “k” for characterising set when testing FSM?
I am supposed to design the tests for state machine software. I have covered all states and all transitions. The last step is to detect the hidden states (states that look the same but internally ...
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0answers
119 views
Design for consuming list items for a state machine like structure
I'm trying to improve this document parser and there is one main loop that goes over all of the main elements (let's call them Nodes). Each step (Step) can either Consume or Ignore the Node that it is ...
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4answers
5k views
How should state machines handle exceptions in actions?
State machines, for example UML state machines, statecharts or other finite state machines, allow actions to be executed when a state machine takes a transition between states or is within a state.
...
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votes
1answer
2k views
How does one combine the state pattern and the component pattern?
Suppose we have a class Player with classes PhysicsComponent, InputComponent and StandingState, DuckingState.
The class Player itself does not have an input function, the InputComponent does. But ...
0
votes
1answer
128 views
Do I have to state the value of elapsed time in state-charts?
I am modelling a system that requires a state-chart before implementation.
Given These Images:
Main Questions:
Can I use the word "Elapsed Time" if I do not know how long it will take to finish the ...
4
votes
2answers
769 views
A simple GUI app: states
I'm making a Windows Forms app:
It is client-server. Authorization, then load some data from server, then send back some statistics from time to time.
You should go through a bootstrapping procedure, ...
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2answers
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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
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1answer
343 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
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1answer
163 views
In OOP which object is common to update the state of an object when working with State Machines?
I'm about to implement my first State Machine and I'm left with one question, which is the acceptable coding form on who should change the state of the object/entity? Should the StateMachine change ...
4
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2answers
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Trouble with circular dependency in state machine design
I am trying to develop the structure for a basic state machine that can also take in input and produce output. I've hit a bit of a mental block in trying to figure out how to model the relationship ...
