Struct Queue

pub struct Queue<T, P: Eq + PartialEq + Ord> { /* private fields */ }

A priority queue that stores arbitrary data sorted by time

Items of type T are stored in order by f64 time and called Plan<T>. Plans can have priorities given by some specified orderable type P. When plans are created they are sequentially assigned a PlanId that is a wrapped u64. If two plans are scheduled for the same time then the plan with the lowest priority is placed earlier. If two plans have the same time and priority then the plan that is scheduled first (i.e., that has the lowest id) is placed earlier.

The time, plan id, and priority are stored in a binary heap of Entry<P> objects. The data payload of the event is stored in a hash map by plan id. Plan cancellation occurs by removing the corresponding entry from the data hash map.

Implementations

impl<T, P: Eq + PartialEq + Ord> Queue<T, P>

pub fn new() -> Queue<T, P>

Create a new empty Queue<T>

pub fn add_plan(&mut self, time: f64, data: T, priority: P) -> PlanId

Add a plan to the queue at the specified time

Returns a PlanId for the newly-added plan that can be used to cancel it if needed.

pub fn cancel_plan(&mut self, plan_id: &PlanId) -> Option<T>

Cancel a plan that has been added to the queue

pub fn is_empty(&self) -> bool

pub fn next_time(&self) -> Option<f64>

pub fn get_next_plan(&mut self) -> Option<Plan<T>>

Retrieve the earliest plan in the queue

Returns the next plan if it exists or else None if the queue is empty

pub fn list_schedules(&self, at_most: usize) -> Vec<&PlanSchedule<P>>

Returns a list of length at_most, or unbounded if at_most=0, of active scheduled PlanSchedules ordered as they are in the queue itself.

Trait Implementations

impl<T, P: Eq + PartialEq + Ord> Default for Queue<T, P>

fn default() -> Self

Returns the “default value” for a type.