/**
* Location: src/database/services/cache/strategies/BaseCacheStrategy.ts
*
* Purpose: Base implementation of cache strategy with common logic
* Implements Strategy pattern with Template Method for customization
*
* Used by: Specific cache strategies (FileCache, EmbeddingCache, etc.)
* Dependencies: CacheStrategy interface
*/
import { CachedEntry, CacheStrategy, CacheStatistics } from './CacheStrategy';
/**
* Base cache strategy with common implementation
*/
export abstract class BaseCacheStrategy<T extends CachedEntry> implements CacheStrategy<T> {
protected cache = new Map<string, T>();
set(key: string, entry: T): void {
this.cache.set(key, entry);
}
get(key: string): T | null {
const entry = this.cache.get(key);
if (!entry) {
return null;
}
// Check if expired
if (this.isExpired(entry)) {
this.cache.delete(key);
return null;
}
// Update access statistics
entry.accessCount++;
entry.lastAccess = Date.now();
return entry;
}
has(key: string): boolean {
const entry = this.cache.get(key);
if (!entry) {
return false;
}
if (this.isExpired(entry)) {
this.cache.delete(key);
return false;
}
return true;
}
delete(key: string): boolean {
return this.cache.delete(key);
}
clear(): void {
this.cache.clear();
}
getAll(): Map<string, T> {
return new Map(this.cache);
}
getStatistics(): CacheStatistics {
const entries = Array.from(this.cache.values());
const count = entries.length;
if (count === 0) {
return { count: 0, sizeMB: 0, oldestEntry: 0, newestEntry: 0 };
}
const sizeMB = entries.reduce((sum, entry) => sum + (entry.size / (1024 * 1024)), 0);
const timestamps = entries.map(entry => entry.timestamp);
return {
count,
sizeMB,
oldestEntry: Math.min(...timestamps),
newestEntry: Math.max(...timestamps)
};
}
cleanup(now: number): number {
let cleanedCount = 0;
for (const [key, entry] of this.cache.entries()) {
if (this.isExpired(entry, now)) {
this.cache.delete(key);
cleanedCount++;
}
}
return cleanedCount;
}
protected isExpired(entry: T, now?: number): boolean {
const currentTime = now || Date.now();
return (currentTime - entry.timestamp) > entry.ttl;
}
}
