| /* |
| * Copyright (C) 2016 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.os; |
| |
| import android.annotation.NonNull; |
| import android.annotation.Nullable; |
| |
| import java.util.concurrent.CompletableFuture; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| |
| /** |
| * Extends ResultReceiver to allow the server end of the ResultReceiver to synchronously wait |
| * on the response from the client. This enables an RPC like system but with the ability to |
| * timeout and discard late results. |
| * |
| * NOTE: Can only be used for one response. Subsequent responses on the same instance are ignored. |
| * {@hide} |
| */ |
| public class SynchronousResultReceiver extends ResultReceiver { |
| public static class Result { |
| public int resultCode; |
| @Nullable public Bundle bundle; |
| |
| public Result(int resultCode, @Nullable Bundle bundle) { |
| this.resultCode = resultCode; |
| this.bundle = bundle; |
| } |
| } |
| |
| private final CompletableFuture<Result> mFuture = new CompletableFuture<>(); |
| private final String mName; |
| |
| public SynchronousResultReceiver() { |
| super((Handler) null); |
| mName = null; |
| } |
| |
| /** |
| * @param name Name for logging purposes |
| */ |
| public SynchronousResultReceiver(String name) { |
| super((Handler) null); |
| mName = name; |
| } |
| |
| @Override |
| final protected void onReceiveResult(int resultCode, Bundle resultData) { |
| super.onReceiveResult(resultCode, resultData); |
| mFuture.complete(new Result(resultCode, resultData)); |
| } |
| |
| public String getName() { |
| return mName; |
| } |
| |
| /** |
| * Blocks waiting for the result from the remote client. |
| * |
| * @return the Result |
| * @throws TimeoutException if the timeout in milliseconds expired. |
| */ |
| public @NonNull Result awaitResult(long timeoutMillis) throws TimeoutException { |
| final long deadline = System.currentTimeMillis() + timeoutMillis; |
| while (timeoutMillis >= 0) { |
| try { |
| return mFuture.get(timeoutMillis, TimeUnit.MILLISECONDS); |
| } catch (ExecutionException e) { |
| // This will NEVER happen. |
| throw new AssertionError("Error receiving response", e); |
| } catch (InterruptedException e) { |
| // The thread was interrupted, try and get the value again, this time |
| // with the remaining time until the deadline. |
| timeoutMillis -= deadline - System.currentTimeMillis(); |
| } |
| } |
| throw new TimeoutException(); |
| } |
| |
| } |