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Collection

ave_actors_store::database

Trait Collection 

Source 
pub trait Collection:
    Sync
    + Send
    + 'static {
    // Required methods
    fn name(&self) -> &str;
    fn get(&self, key: &str) -> Result<Vec<u8>, Error>;
    fn put(&mut self, key: &str, data: &[u8]) -> Result<(), Error>;
    fn del(&mut self, key: &str) -> Result<(), Error>;
    fn last(&self) -> Result<Option<(String, Vec<u8>)>, Error>;
    fn purge(&mut self) -> Result<(), Error>;
    fn iter<'a>(&'a self, reverse: bool) -> Result<CollectionIter<'a>, Error>;

    // Provided method
    fn get_by_range(
        &self,
        from: Option<String>,
        quantity: isize,
    ) -> Result<Vec<Vec<u8>>, Error> { ... }
}
Expand description

Ordered key-value storage used to persist event sequences.

Keys are typically zero-padded sequence numbers (e.g. "00000000000000000042"), which makes the last-entry and range queries efficient. Implementations must be Send + Sync + 'static.

Required Methods§

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fn name(&self) -> &str

Returns the name identifier of this collection.

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fn get(&self, key: &str) -> Result<Vec<u8>, Error>

Returns the value stored under key.

Returns Error::EntryNotFound if the key does not exist.

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fn put(&mut self, key: &str, data: &[u8]) -> Result<(), Error>

Associates data with key, inserting or replacing any previous value.

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fn del(&mut self, key: &str) -> Result<(), Error>

Removes the entry for key.

Returns Error::EntryNotFound if the key does not exist.

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fn last(&self) -> Result<Option<(String, Vec<u8>)>, Error>

Returns the last key-value pair in insertion/sort order, or None if the collection is empty.

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fn purge(&mut self) -> Result<(), Error>

Removes all entries from the collection.

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fn iter<'a>(&'a self, reverse: bool) -> Result<CollectionIter<'a>, Error>

Returns an iterator over all key-value pairs.

Pass reverse = true to iterate in descending key order. Returns an error if the backend cannot acquire the necessary locks to start iteration; individual items in the iterator may also yield errors.

Provided Methods§

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fn get_by_range( &self, from: Option<String>, quantity: isize, ) -> Result<Vec<Vec<u8>>, Error>

Returns at most quantity.abs() values, optionally starting after from.

If from is Some(key), iteration begins at the entry immediately after key. A positive quantity iterates forward; negative iterates in reverse. Returns Error::EntryNotFound if from is provided but does not exist.

Implementors§