1 /* 2 * Copyright (C) 2017 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.inputmethodservice.cts.devicetest; 18 19 import static org.junit.Assert.fail; 20 21 import java.util.concurrent.TimeUnit; 22 23 /** 24 * Utility class for busy waiting. 25 */ 26 final class BusyWaitUtils { 27 28 private static final long POLLING_INTERVAL = TimeUnit.MILLISECONDS.toMillis(50); 29 30 @FunctionalInterface 31 interface PollingCondition { 32 boolean check() throws Exception; 33 } 34 35 // This is utility class, can't instantiate. 36 private BusyWaitUtils() {} 37 38 /** 39 * Busy waiting until {@link PollingCondition#check()} returns {@code true}. 40 * @param condition {@link PollingCondition} to be checked. 41 * @param timeout milliseconds before time out happens. 42 * @param message when time out happens, {@link org.junit.Assert#fail(String)} is called with 43 * this message. 44 * @throws Exception 45 */ 46 static void pollingCheck(final PollingCondition condition, final long timeout, 47 final String message) throws Exception { 48 if (waitFor(condition, timeout)) { 49 return; 50 } 51 fail(message); 52 } 53 54 /** 55 * Busy waiting until {@link PollingCondition#check()} returns {@code true}. 56 * @param condition {@link PollingCondition} to be checked. 57 * @param timeout milliseconds before time out happens. 58 * @return true when {@code condition} returns {@code true}, false when timed out. 59 * @throws Exception 60 */ 61 static boolean waitFor(final PollingCondition condition, final long timeout) throws Exception { 62 for (long remaining = timeout; remaining > 0; remaining -= POLLING_INTERVAL) { 63 if (condition.check()) { 64 return true; 65 } 66 Thread.sleep(POLLING_INTERVAL); 67 } 68 return false; 69 } 70 } 71
