/**
 * @license
 * Copyright 2017 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import { Equatable } from './misc';
/**
 * A map implementation that uses objects as keys. Objects must implement the
 * Equatable interface and must be immutable. Entries in the map are stored
 * together with the key being produced from the mapKeyFn. This map
 * automatically handles collisions of keys.
 */
export declare class ObjectMap<KeyType extends Equatable<KeyType>, ValueType> {
    private mapKeyFn;
    /**
     * The inner map for a key -> value pair. Due to the possibility of
     * collisions we keep a list of entries that we do a linear search through
     * to find an actual match. Note that collisions should be rare, so we still
     * expect near constant time lookups in practice.
     */
    private inner;
    constructor(mapKeyFn: (key: KeyType) => string);
    /** Get a value for this key, or undefined if it does not exist. */
    get(key: KeyType): ValueType | undefined;
    has(key: KeyType): boolean;
    /** Put this key and value in the map. */
    set(key: KeyType, value: ValueType): void;
    /**
     * Remove this key from the map. Returns a boolean if anything was deleted.
     */
    delete(key: KeyType): boolean;
    forEach(fn: (key: KeyType, val: ValueType) => void): void;
    isEmpty(): boolean;
}