Trait Cache 

pub trait Cache<K: CacheKey, V: CacheValue>: Send + Sync {
    // Required methods
    fn get(&self, key: &K) -> Option<V>;
    fn put(&self, key: &K, value: V) -> Option<V>;
    fn remove(&self, k: &K) -> Option<V>;
    fn contains_key(&self, k: &K) -> bool;
    fn len(&self) -> usize;
    fn clear(&self);
    fn name(&self) -> String;
    fn cache_limit(&self) -> usize;
    fn update_cache_limit(&self, limit: usize);
    fn cache_ttl(&self) -> Option<Duration>;
    fn update_cache_ttl(&self, _ttl: Option<Duration>);
    fn drop_table_entries(&self, table_ref: &TableReference) -> Result<()>;
    fn list_entries(&self) -> HashMap<K, CacheEntryInfo<V>>;

    // Provided method
    fn is_empty(&self) -> bool { ... }
}

Base trait for cache implementations with common operations.

This trait provides the fundamental cache operations (get, put, remove, etc.) that all cache types share.

Thread Safety

Implementations must handle their own locking via internal mutability, as methods do not take mutable references and may be accessed by multiple concurrent queries.

Required Methods

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

Get a cached entry if it exists.

fn put(&self, key: &K, value: V) -> Option<V>

Store a value in the cache.

Returns the previous value if one existed.

fn remove(&self, k: &K) -> Option<V>

Remove an entry from the cache, returning the value if it existed.

fn contains_key(&self, k: &K) -> bool

Check if the cache contains a specific key.

fn len(&self) -> usize

Fetch the total number of cache entries.

fn clear(&self)

Remove all entries from the cache.

fn name(&self) -> String

Return the cache name.

fn cache_limit(&self) -> usize

Current memory budget, in bytes.

fn update_cache_limit(&self, limit: usize)

Change the memory budget in bytes.

fn cache_ttl(&self) -> Option<Duration>

Time-to-live applied to newly inserted entries, or None if entries never expire on their own.

fn update_cache_ttl(&self, _ttl: Option<Duration>)

Change the TTL applied to subsequent inserts.

fn drop_table_entries(&self, table_ref: &TableReference) -> Result<()>

Invalidate every entry associated with table_ref.

fn list_entries(&self) -> HashMap<K, CacheEntryInfo<V>>

Snapshot of all current entries with per-entry metadata (size, hits, expiration) for diagnostics and observability.

Provided Methods

fn is_empty(&self) -> bool

Check if the cache collection is empty.

Trait Implementations

impl<K: CacheKey, V: CacheValue> Debug for dyn Cache<K, V>

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

Formats the value using the given formatter.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl<K: CacheKey, V: CacheValue> Cache<K, V> for DefaultCache<K, V>