Struct LastValue 

pub struct LastValue<T> { /* private fields */ }

A channel that stores the last written value.

When multiple values are written in a single step, only the last one is kept. This is the most common channel type.

Example

use rust_langgraph::channels::{BaseChannel, LastValue};

let mut channel = LastValue::<i32>::new();
channel.update(vec![serde_json::json!(1), serde_json::json!(2)]).unwrap();
assert_eq!(channel.get().unwrap(), Some(serde_json::json!(2)));

Implementations

impl<T> LastValue<T>

pub fn new() -> Self

Create a new empty LastValue channel

pub fn with_value(value: T) -> Self

Create a LastValue channel with an initial value

Trait Implementations

impl<T> BaseChannel for LastValue<T>

where T: Serialize + for<'de> Deserialize<'de> + Clone + Send + Sync + Debug + 'static,

fn get(&self) -> Result<Option<Value>>

Get the current value as JSON

fn update(&mut self, values: Vec<Value>) -> Result<()>

Update the channel with new values

fn checkpoint(&self) -> Result<Value>

Serialize the channel state for checkpointing

fn from_checkpoint(data: Value) -> Result<Box<dyn BaseChannel>>

Restore the channel state from a checkpoint

fn type_name(&self) -> &'static str

Get the channel’s type name for debugging

fn is_empty(&self) -> bool

Check if the channel is empty

impl<T: Clone> Clone for LastValue<T>

fn clone(&self) -> LastValue<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for LastValue<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Default for LastValue<T>

fn default() -> Self

Returns the “default value” for a type.