Struct MessageId 

pub struct MessageId {
    pub ledger_id: u64,
    pub entry_id: u64,
    pub partition: i32,
    pub batch_index: i32,
    pub batch_size: i32,
}

A logical message identifier (ledger / entry / batch / partition).

Mirrors the Java MessageId interface. partition defaults to -1 for non-partitioned topics; batch_index defaults to -1 for non-batched messages.

Structural equality (PIP-180)

Two MessageIds compare equal iff every structural field matches — (ledger_id, entry_id, partition, batch_index, batch_size). On a shadow topic (PIP-180, ADR-0033) the broker presents messages with the source MessageId (same ledger/entry pointers as the original write), so a shadow-side reader observes ids that compare equal to the source-side reader’s ids — “same message” is structurally evident and needs no out-of-band correlation key.

PIP-460 scalable-topic segment (experimental)

Under feature = "scalable-topics" the id carries an optional segment_id field. The derived PartialEq / Ord / Hash give exactly the cross-mode contract ADR-0093 specifies: two v4 ids both carry None, so the segment field is a tie and the v4 invariant is preserved bit-for-bit; a scalable id (Some(_)) never compares equal to a v4 id (None) — so callers can’t accidentally deduplicate across the scalable / partitioned mode boundary.

Fields

ledger_id: u64

Bookkeeper ledger id where the entry lives.

entry_id: u64

Entry id within the ledger.

partition: i32

Partition index, -1 if non-partitioned.

batch_index: i32

Index within a batched entry, -1 if not batched.

batch_size: i32

Size of the batch the message came from, -1 if not batched.

Implementations

impl MessageId

pub const EARLIEST: MessageId

A sentinel “earliest” position. Mirrors MessageId.earliest.

pub const LATEST: MessageId

A sentinel “latest” position. Mirrors MessageId.latest.

pub fn from_pb(pb: &MessageIdData) -> MessageId

Construct a message id from the wire protobuf representation.

pub fn to_pb(self) -> MessageIdData

Encode this message id back into its protobuf form.

pub fn to_bytes(self) -> Vec<u8>

Serialise this message id to a portable byte string. Mirrors Java MessageId#toByteArray — encodes a MessageIdData protobuf message. Callers can stash the result anywhere (Kafka header, DB column, log line) and reconstruct via Self::from_bytes later.

pub fn from_bytes(bytes: &[u8]) -> Option<MessageId>

Reconstruct a message id from the byte string produced by Self::to_bytes. Mirrors Java MessageId#fromByteArray. Returns None if bytes is not a valid protobuf MessageIdData.

Trait Implementations

impl Clone for MessageId

fn clone(&self) -> MessageId

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for MessageId

impl Debug for MessageId

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

Formats the value using the given formatter.

impl Display for MessageId

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

Formats the value using the given formatter.

impl Eq for MessageId

impl Hash for MessageId

fn hash<__H>(&self, state: &mut __H)

where __H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for MessageId

fn cmp(&self, other: &MessageId) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for MessageId

fn eq(&self, other: &MessageId) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl PartialOrd for MessageId

fn partial_cmp(&self, other: &MessageId) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for MessageId