/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
import { Observable } from 'rxjs/Observable';
import { NgControl } from '@angular/forms';
/** An interface which allows a control to work inside of a `MdFormField`. */
export declare abstract class MdFormFieldControl<T> {
    /** The value of the control. */
    value: T;
    /**
     * Stream that emits whenever the state of the control changes such that the parent `MdFormField`
     * needs to run change detection.
     */
    readonly stateChanges: Observable<void>;
    /** The element ID for this control. */
    readonly id: string;
    /** The placeholder for this control. */
    readonly placeholder: string;
    /** Gets the NgControl for this control. */
    readonly ngControl: NgControl | null;
    /** Whether the control is focused. */
    readonly focused: boolean;
    /** Whether the control is empty. */
    readonly empty: boolean;
    /** Whether the control is required. */
    readonly required: boolean;
    /** Whether the control is disabled. */
    readonly disabled: boolean;
    /** Whether the control is in an error state. */
    readonly errorState: boolean;
    /** Sets the list of element IDs that currently describe this control. */
    abstract setDescribedByIds(ids: string[]): void;
    /** Focuses this control. */
    abstract focus(): void;
}