Trait Cache 

pub trait Cache<K, V>
where
    K: AsRef<str>,
    V: Clone + Serialize + for<'de> Deserialize<'de>,
{
    // Required methods
    fn get(&self, key: &K) -> Option<V>;
    fn set(&self, key: &K, value: &V, ttl: Duration) -> Result<(), CacheError>;
    fn invalidate(&self, key: &K) -> Result<(), CacheError>;
    fn clear(&self) -> Result<(), CacheError>;
}

What: Trait for cache implementations.

Inputs:

• K: Cache key type (must be AsRef<str>)
• V: Value type (must be Clone + Serialize + Deserialize)

Output:

• Various methods return Option<V> for cache hits or Result for operations

Details:

• Provides abstract interface for cache operations
• Supports get, set, invalidate, and clear operations
• Generic over value type to support different cached data

Required Methods

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

What: Get a value from the cache.

Inputs:

• key: Cache key to look up

Output:

• Option<V> containing cached value if found and not expired, None otherwise

Details:

• Returns None if key not found or entry has expired
• Should check TTL before returning value

fn set(&self, key: &K, value: &V, ttl: Duration) -> Result<(), CacheError>

What: Store a value in the cache.

Inputs:

• key: Cache key
• value: Value to cache
• ttl: Time-to-live duration

Output:

• Result<(), CacheError> indicating success or failure

Details:

• Stores value with specified TTL
• May evict entries if cache is full (LRU)
• Should not block the main operation

Errors

• Returns Err(CacheError::Serialization) if value serialization fails
• Returns Err(CacheError::Io) if disk cache write fails (disk cache only)

fn invalidate(&self, key: &K) -> Result<(), CacheError>

What: Invalidate a specific cache entry.

Inputs:

• key: Cache key to invalidate

Output:

• Result<(), CacheError> indicating success or failure

Details:

• Removes the entry from cache
• Safe to call if key doesn’t exist

Errors

• Returns Err(CacheError::Io) if disk cache file removal fails (disk cache only)

fn clear(&self) -> Result<(), CacheError>

What: Clear all entries from the cache.

Inputs: None

Output:

• Result<(), CacheError> indicating success or failure

Details:

• Removes all entries from cache
• Useful for cache invalidation operations

Errors

• Returns Err(CacheError::Io) if disk cache cleanup fails (disk cache only)

Implementors