import { EventEmitter } from '@angular/core';
import * as i0 from "@angular/core";
/**
 * A common base class to handle value for single and multiple selection.
 * {@link MultiSelectDirectiveBase} and {@link SingleSelectDirectiveBase} implement and
 * provide this interface. Note that the main purpose for such design is **not**
 * to abstract out selection behavior. But to have accurate `value` and `valueChange`
 * type for single and multiple selection mode. It would be possible to fully abstract out
 * the selection behavior, and have Select component not know anything about selection being
 * multiple or not, but it doesn't seem such a clear abstraction, and also not worth the additional
 * complexity.
 *
 * At least one directive has to be defined for each select component to provide SelectValueHolder,
 * extending either {@link MultiSelectDirectiveBase} or {@link SingleSelectDirectiveBase}
 */
export declare abstract class SelectValueHolder<T = unknown> {
    abstract value: T;
    abstract valueChange: EventEmitter<T>;
    abstract setFromListboxValue(value: readonly string[]): void;
    abstract getListboxValue(): readonly string[];
}
/**
 * Enables multiple selection. When present, `value` will be of type `string[]`, and `valueChange`
 * will emit `string[]`.
 *
 * Each select component can define a directive with the right selector (usually based on
 * the presence of `multiple` attribute) to enable multiple selection.
 */
export declare class MultiSelectDirectiveBase extends SelectValueHolder<string[]> {
    value: string[];
    valueChange: EventEmitter<string[]>;
    setFromListboxValue(value: string[]): void;
    getListboxValue(): readonly string[];
    static ɵfac: i0.ɵɵFactoryDeclaration<MultiSelectDirectiveBase, never>;
    static ɵdir: i0.ɵɵDirectiveDeclaration<MultiSelectDirectiveBase, never, never, { "value": "value"; }, { "valueChange": "valueChange"; }, never, never, false, never>;
}
/**
 * Enables single selection, the default behavior of select.
 * When present, `value` will be of type `string`, and `valueChange` will emit `string`.
 *
 * Each select component has to define a directive with the right selector (usually based on
 * the absence of `multiple` attribute) to enable single selection.
 */
export declare class SingleSelectDirectiveBase extends SelectValueHolder<string> {
    get value(): string;
    set value(value: string);
    private _value;
    private values;
    valueChange: EventEmitter<string>;
    setFromListboxValue(value: string[]): void;
    getListboxValue(): readonly string[];
    static ɵfac: i0.ɵɵFactoryDeclaration<SingleSelectDirectiveBase, never>;
    static ɵdir: i0.ɵɵDirectiveDeclaration<SingleSelectDirectiveBase, never, never, { "value": "value"; }, { "valueChange": "valueChange"; }, never, never, false, never>;
}