Struct PartitionAggregateState 

pub struct PartitionAggregateState { /* private fields */ }

Per-partition aggregate state.

K is the partition/group key (typically a String). V is the typed aggregate value held for that key.

Implementations

impl PartitionAggregateState

pub fn new() -> Self

Empty state.

pub fn get(&self, key: &str) -> Option<&PartitionAggregateValue>

Look up the current value for key.

pub fn put(&mut self, key: impl Into<String>, value: PartitionAggregateValue)

Insert or replace the value for key.

pub fn len(&self) -> usize

Number of keys currently tracked.

pub fn is_empty(&self) -> bool

True iff no keys are tracked.

pub fn iter(&self) -> impl Iterator<Item = (&String, &PartitionAggregateValue)>

Iterate over all (key, value) pairs.

pub fn encode(&self) -> Vec<u8>

Encode this state to a deterministic byte vector.

Format

• [u32 len] — number of entries.
• len × [u32 key_len][key…][u8 tag][payload].
• Tag/payload:
  • 0x01 Count: [u64].
  • 0x02 Sum: [f64].
  • 0x03 Min: [f64].
  • 0x04 Max: [f64].
  • 0x05 Mean: [f64 sum][u64 count].

All integers are little-endian.

pub fn decode(buf: &[u8]) -> Result<Self, StreamError>

Decode a state previously produced by Self::encode.

Trait Implementations

impl Clone for PartitionAggregateState

fn clone(&self) -> PartitionAggregateState

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PartitionAggregateState

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

Formats the value using the given formatter.

impl Default for PartitionAggregateState

fn default() -> Self

Returns the “default value” for a type.