Trait erdos::dataflow::state::State

pub trait State: 'static + Send + Sync {
    type Item: Default;
    fn commit(&mut self, timestamp: &Timestamp);
    fn last_committed_timestamp(&self) -> Timestamp;
    fn at(&mut self, timestamp: &Timestamp) -> Option<&mut Self::Item>;
}

The State trait must be implemented by the state exposed to the operators by ERDOS.

Associated Types

type Item: Default

Required methods

fn commit(&mut self, timestamp: &Timestamp)

The commit method commits the final state for a given timestamp.

fn last_committed_timestamp(&self) -> Timestamp

Retrieves the last committed timestamp by this state. This method can be used in conjunction with Self::at to retrieve the latest committed state.

fn at(&mut self, timestamp: &Timestamp) -> Option<&mut Self::Item>

Retrieve the state at a given timestamp. If the state for that timestamp hasn’t been initialized yet, invoke the default method on the Self::Item type, and return the newly created state for that timestamp.

Implementations on Foreign Types

impl State for ()

State implementation for () to be used by operators that are stateless.

type Item = ()

fn commit(&mut self, _timestamp: &Timestamp)

fn last_committed_timestamp(&self) -> Timestamp

fn at(&mut self, _timestamp: &Timestamp) -> Option<&mut Self::Item>

Implementors

impl<S> State for TimeVersionedState<S> where
    S: 'static + Default + Send + Sync, 

type Item = S