import { Threshold } from '@thermopylae/core.declarations';
import { CacheReplacementPolicy, Deleter, EntryValidity } from '../../contracts/cache-replacement-policy';
import { CacheEntry } from '../../contracts/commons';
import { BucketEntryNode } from '../../data-structures/bucket-list/ordered-bucket-list';
import { CacheBackendElementsCount } from '../../contracts/cache-backend';
/**
 * @private
 */
interface EvictableCacheEntry<Key, Value> extends CacheEntry<Key, Value>, BucketEntryNode<EvictableCacheEntry<Key, Value>> {
}
/**
 * Base class for LFU policies.
 *
 * @private
 *
 * @template Key				Type of the key.
 * @template Value				Type of the value.
 * @template ArgumentsBundle	Type of the arguments bundle.
 */
declare abstract class BaseLFUEvictionPolicy<Key, Value, ArgumentsBundle> implements CacheReplacementPolicy<Key, Value, ArgumentsBundle> {
    private readonly frequencies;
    private readonly cacheMaxCapacity;
    private readonly cacheBackendElementsCount;
    private deleteFromCache;
    /**
     * @param cacheMaxCapacity				{@link Cache} maximum capacity.
     * @param cacheBackendElementsCount		Cache backend elements count.
     */
    constructor(cacheMaxCapacity: Threshold, cacheBackendElementsCount: CacheBackendElementsCount);
    /**
     * @returns		Total number of elements from frequency list.
     */
    get size(): number;
    /**
     * @inheritDoc
     */
    onHit(entry: EvictableCacheEntry<Key, Value>): EntryValidity;
    /**
     * @inheritDoc
     */
    onMiss(): void;
    /**
     * @inheritDoc
     */
    onSet(entry: EvictableCacheEntry<Key, Value>): void;
    /**
     * @inheritDoc
     */
    onUpdate(_entry: EvictableCacheEntry<Key, Value>): void;
    /**
     * @inheritDoc
     */
    onDelete(entry: EvictableCacheEntry<Key, Value>): void;
    /**
     * @inheritDoc
     */
    onClear(): void;
    /**
     * @inheritDoc
     */
    setDeleter(deleter: Deleter<Key, Value>): void;
    private evict;
    /**
     * @returns 	Entry initial starting frequency.
     */
    protected abstract get initialFrequency(): number;
    /**
     * Delegate called before entry needs to be inserted in a frequency bucket. <br/>
     * Entry will be inserted in the bucket that has frequency equal to result returned by this function.
     *
     * @param entry			Entry for which score needs to be computed.
     * @param entryScore    Current score of the entry.
     *
     * @returns     New frequency of the entry.
     */
    protected abstract computeEntryFrequency(entry: EvictableCacheEntry<Key, Value>, entryScore: number): number;
    /**
     * Delegate called after item has been evicted from cache.
     *
     * @param frequency		Frequency of the evicted item.
     */
    protected abstract onEvict(frequency: number): void;
}
export { BaseLFUEvictionPolicy, EvictableCacheEntry };