| /* |
| * Copyright (C) 2021 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.compatibility.common.util; |
| |
| import static junit.framework.TestCase.fail; |
| |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| /** |
| * Subclass this to create a blocking version of a callback. For example: |
| * |
| * {@code |
| * private static class KeyChainAliasCallback extends BlockingCallback<String> implements |
| * android.security.KeyChainAliasCallback { |
| * @Override |
| * public void alias(final String chosenAlias) { |
| * callbackTriggered(chosenAlias); |
| * } |
| * } |
| * } |
| * |
| * <p>an instance of KeyChainAliasCallback can then be passed into a method, and the result can |
| * be fetched using {@code .await()}; |
| */ |
| public abstract class BlockingCallback<E> { |
| private static final int DEFAULT_TIMEOUT_SECONDS = 120; |
| |
| private final CountDownLatch mLatch = new CountDownLatch(1); |
| private AtomicReference<E> mValue = new AtomicReference<>(); |
| |
| /** Call this method from the callback method to mark the response as received. */ |
| protected void callbackTriggered(E value) { |
| mValue.set(value); |
| mLatch.countDown(); |
| } |
| |
| /** |
| * Fetch the value passed into the callback. |
| * |
| * <p>Throws an {@link AssertionError} if the callback is not triggered in |
| * {@link #DEFAULT_TIMEOUT_SECONDS} seconds. |
| */ |
| public E await() throws InterruptedException { |
| return await(DEFAULT_TIMEOUT_SECONDS, TimeUnit.SECONDS); |
| } |
| |
| /** |
| * Fetch the value passed into the callback. |
| * |
| * <p>Throws an {@link AssertionError} if the callback is not triggered before the timeout |
| * elapses. |
| */ |
| public E await(long timeout, TimeUnit unit) throws InterruptedException { |
| if (!mLatch.await(timeout, unit)) { |
| fail("Callback was not received"); |
| } |
| return mValue.get(); |
| } |
| } |