Struct DashMapCache 

pub struct DashMapCache { /* private fields */ }

Simple concurrent cache using DashMap

Use Case: Educational reference, simple concurrent scenarios

Features:

• Lock-free concurrent reads/writes
• Manual TTL tracking
• No automatic eviction (manual cleanup needed)
• Minimal memory overhead

Limitations:

• No automatic eviction policy (LRU, LFU, etc.)
• No size limits (unbounded growth)
• Manual TTL cleanup required

When to use:

• Learning how to implement cache backends
• Simple use cases with predictable data sizes
• When you need full control over eviction logic

Example:

use multi_tier_cache::backends::DashMapCache;
use multi_tier_cache::traits::CacheBackend;
use std::time::Duration;

let cache = DashMapCache::new();
let value = serde_json::json!({"user": "alice"});

cache.set_with_ttl("user:1", value.clone(), Duration::from_secs(60)).await?;
let cached = cache.get("user:1").await;
assert_eq!(cached, Some(value));

Implementations

impl DashMapCache

pub fn new() -> Self

Create new DashMap cache

pub fn cleanup_expired(&self) -> usize

Cleanup expired entries (should be called periodically)

Note: DashMap doesn’t have automatic eviction, so you need to call this method periodically to remove expired entries.

pub fn len(&self) -> usize

Get current cache size

pub fn is_empty(&self) -> bool

Check if cache is empty

Trait Implementations

impl CacheBackend for DashMapCache

Implement CacheBackend trait for DashMapCache

fn get<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, ) -> Pin<Box<dyn Future<Output = Option<Value>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Get value from cache by key

fn set_with_ttl<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, value: Value, ttl: Duration, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Set value in cache with time-to-live

fn remove<'life0, 'life1, 'async_trait>( &'life0 self, key: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<()>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Remove value from cache

fn health_check<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = bool> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Check if cache backend is healthy

fn name(&self) -> &'static str

Get the name of this cache backend

impl Default for DashMapCache

fn default() -> Self

Returns the “default value” for a type.