1/*
2 * Copyright (C) 2013 DroidDriver committers
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.android.droiddriver.validators;
18
19import com.google.android.droiddriver.UiElement;
20import com.google.android.droiddriver.actions.Action;
21
22/**
23 * Interface for validating a UiElement, checked when an action is performed.
24 * For example, in general accessibility mandates that an actionable UiElement
25 * has content description or text.
26 */
27public interface Validator {
28  /**
29   * Returns true if this {@link Validator} applies to {@code element} on this
30   * {@code action}.
31   */
32  boolean isApplicable(UiElement element, Action action);
33
34  /**
35   * Returns {@code null} if {@code element} is valid on this {@code action},
36   * otherwise a string describing the failure.
37   */
38  String validate(UiElement element, Action action);
39}
40