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 
17 package com.android.dialer.common.concurrent;
18 
19 import android.os.AsyncTask;
20 import android.support.annotation.MainThread;
21 import java.util.concurrent.Executor;
22 
23 /**
24  * Interface used to submit {@link AsyncTask} objects to run in the background.
25  *
26  * <p>This interface has a direct parallel with the {@link Executor} interface. It exists to
27  * decouple the mechanics of AsyncTask submission from the description of how that AsyncTask will
28  * execute.
29  *
30  * <p>One immediate benefit of this approach is that testing becomes much easier, since it is easy
31  * to introduce a mock or fake AsyncTaskExecutor in unit/integration tests, and thus inspect which
32  * tasks have been submitted and control their execution in an orderly manner.
33  *
34  * <p>Another benefit in due course will be the management of the submitted tasks. An extension to
35  * this interface is planned to allow Activities to easily cancel all the submitted tasks that are
36  * still pending in the onDestroy() method of the Activity.
37  */
38 public interface AsyncTaskExecutor {
39 
40   /**
41    * Executes the given AsyncTask with the default Executor.
42    *
43    * <p>This method <b>must only be called from the ui thread</b>.
44    *
45    * <p>The identifier supplied is any Object that can be used to identify the task later. Most
46    * commonly this will be an enum which the tests can also refer to. {@code null} is also accepted,
47    * though of course this won't help in identifying the task later.
48    */
49   @MainThread
submit(Object identifier, AsyncTask<T, ?, ?> task, T... params)50   <T> AsyncTask<T, ?, ?> submit(Object identifier, AsyncTask<T, ?, ?> task, T... params);
51 }
52