Gen FSM
Gen FSM[edit]
Gen FSM is a module in Elixir that stands for Generic Finite State Machine. It provides a behavioral abstraction which allows you to define and manage state machines in your programs. This module is built upon the Gen behavior and is widely used for implementing robust and scalable applications.
Features[edit]
- State and event driven behavior
- Asynchronous message passing
- Supports structured error handling
- Built-in supervision
- Scalability and fault-tolerance
Usage[edit]
To use Gen FSM, you need to define a module that implements the `Gen.Server` behavior and use the `GenFSM` macro to define the FSM behavior. Here's a basic example:
```elixir defmodule MyFSM do
use Gen.Server use GenFSM
# Define the states of the FSM defstates :init, :state1, :state2
# Define the events and their resulting state transitions
deftransitions init: { :event1, :state1 },
state1: { :event2, :state2 },
state2: { :event3, :state1 }
# Implement the callback functions
def handle_call(:event1, _from, state) do
{:reply, "Event 1 handled", state}
end
def handle_call(:event2, _from, state) do
{:reply, "Event 2 handled", state}
end
def handle_call(:event3, _from, state) do
{:reply, "Event 3 handled", state}
end
end ```
You can then start and interact with an instance of your FSM:
```elixir {:ok, pid} = GenFSM.start_link(MyFSM, :init)
GenFSM.call(pid, :event1) GenFSM.call(pid, :event2) GenFSM.call(pid, :event3) ```
Benefits[edit]
By using the Gen FSM module, you can leverage the following benefits:
- Better organization of code by encapsulating state-related logic
- Improved maintainability and readability of state machines
- Streamlined error handling through pattern matching
- Simplified supervision and fault tolerance
See Also[edit]
- Elixir - The programming language upon which Gen FSM is built
- Gen - The behavior that Gen FSM is based on