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Projection

allsource_core::application::services::projection

Trait Projection 

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pub trait Projection: Send + Sync {
    // Required methods
    fn name(&self) -> &str;
    fn process(&self, event: &Event) -> Result<()>;
    fn get_state(&self, entity_id: &str) -> Option<Value>;
    fn clear(&self);

    // Provided methods
    fn snapshot(&self) -> Option<Value> { ... }
    fn restore(&self, _snapshot: &Value) -> Result<()> { ... }
}
Expand description

A projection aggregates events into a queryable view

Required Methods§

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fn name(&self) -> &str

Get the name of this projection

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fn process(&self, event: &Event) -> Result<()>

Process an event and update the projection state

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fn get_state(&self, entity_id: &str) -> Option<Value>

Get the current state of the projection for an entity

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fn clear(&self)

Clear all projection state

Provided Methods§

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fn snapshot(&self) -> Option<Value>

Snapshot the entire projection state for checkpointing. Returns None if the projection does not support checkpointing.

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fn restore(&self, _snapshot: &Value) -> Result<()>

Restore projection state from a previously saved snapshot.

Implementors§