Struct HashmapDatabase 

pub struct HashmapDatabase<K: Eq + Hash, V> { /* private fields */ }

The HMapDatabase mimics the behaviour of LMDBDatabase without keeping a persistent copy of the key-value records. It allows key-value pairs to be inserted, retrieved and removed in a thread-safe manner.

Implementations

impl<K: Clone + Eq + Hash, V: Clone> HashmapDatabase<K, V>

pub fn new() -> Self

Creates a new empty HMapDatabase with the specified name

pub fn insert(&self, key: K, value: V) -> Result<(), KeyValStoreError>

Inserts a key-value record into the database. Internally, insert serializes the key and value using bincode and adds the pair into HashMap guarded with a RwLock.

pub fn get(&self, key: &K) -> Result<Option<V>, KeyValStoreError>

Get a value from the key-value database. The retrieved value is deserialized from bincode into V

pub fn is_empty(&self) -> Result<bool, KeyValStoreError>

Returns if the key-value database is empty

pub fn len(&self) -> Result<usize, KeyValStoreError>

Returns the total number of entries recorded in the key-value database.

pub fn for_each<F>(&self, f: F) -> Result<(), KeyValStoreError>

where F: FnMut(Result<(K, V), KeyValStoreError>) -> IterationResult,

Iterate over all the stored records and execute the function f for each pair in the key-value database.

pub fn contains_key(&self, key: &K) -> Result<bool, KeyValStoreError>

Checks whether a record exist in the key-value database that corresponds to the provided key.

pub fn remove(&self, key: &K) -> Result<(), KeyValStoreError>

Remove the record from the key-value database that corresponds with the provided key.

Trait Implementations

impl<K: Default + Eq + Hash, V: Default> Default for HashmapDatabase<K, V>

fn default() -> HashmapDatabase<K, V>

Returns the “default value” for a type.

impl<K: Clone + Eq + Hash, V: Clone> KeyValueStore<K, V> for HashmapDatabase<K, V>

fn insert(&self, key: K, value: V) -> Result<(), KeyValStoreError>

Inserts a key-value pair into the key-value database.

fn get(&self, key: &K) -> Result<Option<V>, KeyValStoreError>

Get the value corresponding to the provided key from the key-value database.

fn get_many(&self, keys: &[K]) -> Result<Vec<V>, KeyValStoreError>

Get the values corresponding to the provided keys from the key-value database.

fn size(&self) -> Result<usize, KeyValStoreError>

Returns the total number of entries recorded in the key-value database.

fn for_each<F>(&self, f: F) -> Result<(), KeyValStoreError>

where F: FnMut(Result<(K, V), KeyValStoreError>) -> IterationResult,

Iterate over all the stored records and execute the function f for each pair in the key-value database.

fn exists(&self, key: &K) -> Result<bool, KeyValStoreError>

Checks whether a record exist in the key-value database that corresponds to the provided key.

fn delete(&self, key: &K) -> Result<(), KeyValStoreError>

Remove the record from the key-value database that corresponds with the provided key.

fn for_each_ok<F>(&self, f: F) -> Result<(), KeyValStoreError>

where Self: Sized, F: FnMut((K, V)) -> IterationResult,

Execute function f for each value in the database. Any errors are filtered out. This is useful for any caller which could not do any better with an error than filtering it out.

fn filter<F>(&self, predicate: F) -> Result<Vec<(K, V)>, KeyValStoreError>

where Self: Sized, F: FnMut(&(K, V)) -> bool,

Return a Vec<(K, V)> filtered by the predicate.

fn filter_take<F>( &self, n: usize, predicate: F, ) -> Result<Vec<(K, V)>, KeyValStoreError>

where Self: Sized, F: FnMut(&(K, V)) -> bool,

Return a Vec<(K, V)> filtered by the predicate. At most n pairs are returned.