Home | History | Annotate | Download | only in testing 
      1 /*
      2  * Copyright (C) 2018 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 android.testing;
     18 
     19 import junit.framework.Assert;
     20 import java.util.concurrent.Callable;
     21 
     22 public abstract class PollingCheck {
     23     private static final long TIME_SLICE = 50;
     24     private long mTimeout = 3000;
     25 
     26     public static interface PollingCheckCondition {
     27         boolean canProceed();
     28     }
     29 
     30     public PollingCheck() {
     31     }
     32 
     33     public PollingCheck(long timeout) {
     34         mTimeout = timeout;
     35     }
     36 
     37     protected abstract boolean check();
     38 
     39     public void run() {
     40         if (check()) {
     41             return;
     42         }
     43 
     44         long timeout = mTimeout;
     45         while (timeout > 0) {
     46             try {
     47                 Thread.sleep(TIME_SLICE);
     48             } catch (InterruptedException e) {
     49                 Assert.fail("unexpected InterruptedException");
     50             }
     51 
     52             if (check()) {
     53                 return;
     54             }
     55 
     56             timeout -= TIME_SLICE;
     57         }
     58 
     59         Assert.fail("unexpected timeout");
     60     }
     61 
     62     public static void check(CharSequence message, long timeout, Callable<Boolean> condition)
     63             throws Exception {
     64         while (timeout > 0) {
     65             if (condition.call()) {
     66                 return;
     67             }
     68 
     69             Thread.sleep(TIME_SLICE);
     70             timeout -= TIME_SLICE;
     71         }
     72 
     73         Assert.fail(message.toString());
     74     }
     75 
     76     public static void waitFor(final PollingCheckCondition condition) {
     77         new PollingCheck() {
     78             @Override
     79             protected boolean check() {
     80                 return condition.canProceed();
     81             }
     82         }.run();
     83     }
     84 
     85     public static void waitFor(long timeout, final PollingCheckCondition condition) {
     86         new PollingCheck(timeout) {
     87             @Override
     88             protected boolean check() {
     89                 return condition.canProceed();
     90             }
     91         }.run();
     92     }
     93 }
     94 
     95