| /* |
| * Copyright (C) 2014 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 android.hardware.cts.helpers; |
| |
| import java.util.HashMap; |
| import java.util.concurrent.CountDownLatch; |
| |
| /** |
| * An abstraction on top of {@link CountDownLatch} to synchronize the results of Activities |
| * started by a parent activity. |
| * |
| * It holds a {@link CountDownLatch} latch for each thread that requests synchronization. |
| * |
| * Each thread requests a {@link Latch} to synchronize an Activity that will be started, by invoking |
| * {@link #bindThread()}, this guarantees that a latch is associated with the thread, and the result |
| * can be retrieved. |
| */ |
| public class ActivityResultMultiplexedLatch { |
| private static final String TAG = "ActivityResultMultiplexedLatch"; |
| |
| private final HashMap<Integer, Entry> mActivityEntries = new HashMap<Integer, Entry>(); |
| |
| /** |
| * A latch for a bound thread. |
| * Applications get an instance by invoking {@link ActivityResultMultiplexedLatch#bindThread()}. |
| */ |
| public class Latch { |
| private Entry mEntry; |
| |
| private Latch(Entry entry) { |
| mEntry = entry; |
| } |
| |
| /** |
| * Awaits for the Activity bound to unblock the current thread. |
| * |
| * @return The result code of the Activity executed. |
| */ |
| public int await() throws InterruptedException { |
| mEntry.latch.await(); |
| return mEntry.resultCode; |
| } |
| |
| /** |
| * @return A request code for the bound thread. It can be passed to the Activity to start. |
| */ |
| public int getRequestCode() { |
| return mEntry.requestCode; |
| } |
| } |
| |
| /** |
| * A class that represents the state for each thread/Activity being tracked. |
| */ |
| private class Entry { |
| public final CountDownLatch latch = new CountDownLatch(1); |
| public final int requestCode; |
| |
| public volatile int resultCode; |
| |
| public Entry(int requestCode) { |
| this.requestCode = requestCode; |
| } |
| } |
| |
| /** |
| * Binds a thread with this object. |
| * |
| * @return A request code (or session Id) for the bound thread. |
| */ |
| public Latch bindThread() { |
| Entry entry; |
| int requestCode = getRequestCode(); |
| |
| synchronized (mActivityEntries) { |
| if (mActivityEntries.containsKey(requestCode)) { |
| throw new IllegalStateException("The thread has already been bound."); |
| } |
| entry = new Entry(requestCode); |
| mActivityEntries.put(requestCode, entry); |
| } |
| |
| return new Latch(entry); |
| } |
| |
| /** |
| * Used by the owner of the instance to record an Activity's result. |
| */ |
| public void onActivityResult(int requestCode, int resultCode) { |
| Entry entry; |
| synchronized (mActivityEntries) { |
| entry = mActivityEntries.remove(requestCode); |
| } |
| if (entry == null) { |
| return; |
| } |
| |
| entry.resultCode = resultCode; |
| entry.latch.countDown(); |
| } |
| |
| // there is no need for a better request Id, only one Activity can be launched at any time |
| private int getRequestCode() { |
| return Thread.currentThread().hashCode(); |
| } |
| } |