1/*
2 * Copyright (C) 2011 The Android Open Source Project
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.android.contacts.util;
18
19import android.os.AsyncTask;
20
21import java.util.concurrent.Executor;
22
23/**
24 * Interface used to submit {@link AsyncTask} objects to run in the background.
25 * <p>
26 * This interface has a direct parallel with the {@link Executor} interface. It exists to decouple
27 * the mechanics of AsyncTask submission from the description of how that AsyncTask will execute.
28 * <p>
29 * One immediate benefit of this approach is that testing becomes much easier, since it is easy to
30 * introduce a mock or fake AsyncTaskExecutor in unit/integration tests, and thus inspect which
31 * tasks have been submitted and control their execution in an orderly manner.
32 * <p>
33 * Another benefit in due course will be the management of the submitted tasks. An extension to this
34 * interface is planned to allow Activities to easily cancel all the submitted tasks that are still
35 * pending in the onDestroy() method of the Activity.
36 */
37public interface AsyncTaskExecutor {
38    /**
39     * Executes the given AsyncTask with the default Executor.
40     * <p>
41     * This method <b>must only be called from the ui thread</b>.
42     * <p>
43     * The identifier supplied is any Object that can be used to identify the task later. Most
44     * commonly this will be an enum which the tests can also refer to. {@code null} is also
45     * accepted, though of course this won't help in identifying the task later.
46     */
47    <T> AsyncTask<T, ?, ?> submit(Object identifier, AsyncTask<T, ?, ?> task, T... params);
48}
49