@dasch-swiss/dsp-js/src/cache/GenericCache.d.ts

JavaScript library that handles API requests to Knora

import { Observable } from "rxjs";
import { ApiResponseError } from "../models/api-response-error";
/**
 * Generic cache class.
 * Fetches information of a specific type from Knora once and caches it.
 * Fetches also dependencies of a requested element (non-blocking).
 * Works also with multiple async requests for the same key, also if not cached yet.
 *
 * @category Internal
 */
export declare abstract class GenericCache<T> {
    /**
     * Cache object: key -> value.
     */
    private cache;
    /**
     * Gets a specific item from the cache.
     * If not cached yet, the information will be retrieved from DSP-API.
     *
     * @param key the id of the item to be returned.
     * @param isDependency true if the item to be returned
     *        is a dependency of another item (recursive call to this method).
     */
    protected getItem(key: string, isDependency?: boolean): Observable<T>;
    /**
     * Deletes an existing entry in the cache and requests information from DSP-API.
     *
     * @param key the id of the information to be returned.
     * @return the item.
     */
    protected reloadItem(key: string): Observable<T>;
    /**
     * Fetches information from DSP-API.
     *
     * @param key the id of the information to be returned.
     * @param isDependency true if the requested key is a dependency of another item.
     * @return the items received from DSP-API.
     */
    protected abstract requestItemFromKnora(key: string, isDependency: boolean): Observable<T[] | ApiResponseError>;
    /**
     * Given an item, determines its key.
     *
     * @param item The item whose key has to be determined.
     */
    protected abstract getKeyOfItem(item: T): string;
    /**
     * Given an item, determines its dependencies on other items.
     *
     * @param item the item whose dependencies have to be determined.
     * @return keys of the items the current item relies on.
     */
    protected abstract getDependenciesOfItem(item: T): string[];
    /**
     * Handle additional items that were resolved with a request.
     *
     * @param items dependencies that have been retrieved.
     */
    private saveAdditionalItems;
    /**
     * Requests dependencies of the items retrieved from DSP-API.
     *
     * @param items items returned from DSP-API to a request.
     */
    private requestDependencies;
}