Home | History | Annotate | Download | only in util 
      1 /*
      2  * Copyright (C) 2015 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.tv.util;
     18 
     19 import android.os.Handler;
     20 import android.os.Looper;
     21 
     22 import java.util.List;
     23 import java.util.concurrent.AbstractExecutorService;
     24 import java.util.concurrent.TimeUnit;
     25 
     26 /**
     27  * An executor service that executes its tasks on the main thread.
     28  *
     29  * Shutting down this executor is not supported.
     30  */
     31 public class MainThreadExecutor extends AbstractExecutorService {
     32 
     33     private final static MainThreadExecutor INSTANCE = new MainThreadExecutor();
     34 
     35     public static MainThreadExecutor getInstance() {
     36         return INSTANCE;
     37     }
     38 
     39     private final Handler mHandler = new Handler(Looper.getMainLooper());
     40 
     41     @Override
     42     public void execute(Runnable runnable) {
     43         if (Looper.getMainLooper() == Looper.myLooper()) {
     44             runnable.run();
     45         } else {
     46             mHandler.post(runnable);
     47         }
     48     }
     49 
     50     /**
     51      * Not supported and throws an exception when used.
     52      */
     53     @Override
     54     @Deprecated
     55     public void shutdown() {
     56         throw new UnsupportedOperationException();
     57     }
     58 
     59     /**
     60      * Not supported and throws an exception when used.
     61      */
     62     @Override
     63     @Deprecated
     64     public List<Runnable> shutdownNow() {
     65         throw new UnsupportedOperationException();
     66     }
     67 
     68     @Override
     69     public boolean isShutdown() {
     70         return false;
     71     }
     72 
     73     @Override
     74     public boolean isTerminated() {
     75         return false;
     76     }
     77 
     78     /**
     79      * Not supported and throws an exception when used.
     80      */
     81     @Override
     82     @Deprecated
     83     public boolean awaitTermination(long l, TimeUnit timeUnit) throws InterruptedException {
     84         throw new UnsupportedOperationException();
     85     }
     86 }