Enum Precondition

pub enum Precondition {
    New,
    Exists,
    ExpectedVersion(Version),
}

A precondition that must be upheld for a command to be executed or for events to be persisted.

Variants

New

Requires that the target aggregate must not have had any events previously applied to it.

Exists

Requires that the target event at least exist, whether as a snapshot, or as having had at least one event applied.

ExpectedVersion(Version)

Requires that the target aggregate have the exact version specified.

Implementations

impl Precondition

pub fn verify(self, current_version: Option<Version>) -> Result<(), Self>

Verifies that the precondition holds, given the current_version. If the precondition is violated, an error is returned with the precondition.

Trait Implementations

impl Clone for Precondition

fn clone(&self) -> Precondition

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Precondition

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

Formats the value using the given formatter.

impl Display for Precondition

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

Formats the value using the given formatter.

impl From<Version> for Precondition

fn from(v: Version) -> Self

Converts to this type from the input type.

impl Hash for Precondition

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

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 PartialEq for Precondition

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for Precondition

impl Eq for Precondition

impl StructuralPartialEq for Precondition