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      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
     50   <T> AsyncTask<T, ?, ?> submit(Object identifier, AsyncTask<T, ?, ?> task, T... params);
     51 }
     52