Struct design_pattern_examples_rust::state::state_context::StateContext

pub struct StateContext {
    current_state: CurrentState,
    behaviors: Vec<(CurrentState, Box<dyn IStateBehavior>)>,
}

Implementation of the state machine. This maintains the context in which the state machine runs.

Fields

current_state: CurrentState

The current state of the machine.

behaviors: Vec<(CurrentState, Box<dyn IStateBehavior>)>

Maps values from the CurrentState enumeration to instances of the IStateBehavior representing the behavior for that state. This vector owns the StateXXX struct instances.

Implementations

impl StateContext

pub fn new() -> StateContext

Constructor

Returns

Returns a new instance of the StateContext struct.

pub fn remove_comments(&mut self, text: &str) -> String

Entry point for callers to filter text. Removes Rust-style line and block comments from the text.

Parameters

• text

  The text from which to remove comments.

Returns

Returns the text as a new string, without the comments.

fn set_next_state(&mut self, new_state: &CurrentState)

Helper method to transition the state machine to the specified state. Does nothing if the new state is the same as the old state.

Parameters

• new_state

  A value from the CurrentState enumeration indicating the state to which to transition.

fn get_behavior(&mut self, state: &CurrentState) -> &mut Box<dyn IStateBehavior>

Helper method to retrieve the behavior corresponding to the given state. A behavior is an implementation of the IStateBehavior trait that can be called to get a new state. There is a different behavior for each state.

The behaviors are created as needed and cached in the StateContext struct.

Parameters

• state

  A value from the CurrentState enumeration indicating which behavior to return.

Returns

Returns a mutable reference to a IStateBehavior instance representing the specified state.