95 lines
3.1 KiB
Java
95 lines
3.1 KiB
Java
/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy of
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* the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations under
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* the License.
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*/
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package android.os;
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import android.annotation.NonNull;
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import android.annotation.Nullable;
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import java.util.concurrent.CompletableFuture;
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import java.util.concurrent.ExecutionException;
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import java.util.concurrent.TimeUnit;
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import java.util.concurrent.TimeoutException;
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/**
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* Extends ResultReceiver to allow the server end of the ResultReceiver to synchronously wait
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* on the response from the client. This enables an RPC like system but with the ability to
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* timeout and discard late results.
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*
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* NOTE: Can only be used for one response. Subsequent responses on the same instance are ignored.
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* {@hide}
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*/
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public class SynchronousResultReceiver extends ResultReceiver {
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public static class Result {
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public int resultCode;
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@Nullable public Bundle bundle;
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public Result(int resultCode, @Nullable Bundle bundle) {
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this.resultCode = resultCode;
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this.bundle = bundle;
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}
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}
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private final CompletableFuture<Result> mFuture = new CompletableFuture<>();
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private final String mName;
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public SynchronousResultReceiver() {
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super((Handler) null);
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mName = null;
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}
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/**
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* @param name Name for logging purposes
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*/
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public SynchronousResultReceiver(String name) {
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super((Handler) null);
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mName = name;
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}
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@Override
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final protected void onReceiveResult(int resultCode, Bundle resultData) {
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super.onReceiveResult(resultCode, resultData);
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mFuture.complete(new Result(resultCode, resultData));
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}
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public String getName() {
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return mName;
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}
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/**
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* Blocks waiting for the result from the remote client.
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*
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* @return the Result
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* @throws TimeoutException if the timeout in milliseconds expired.
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*/
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public @NonNull Result awaitResult(long timeoutMillis) throws TimeoutException {
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final long deadline = System.currentTimeMillis() + timeoutMillis;
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while (timeoutMillis >= 0) {
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try {
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return mFuture.get(timeoutMillis, TimeUnit.MILLISECONDS);
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} catch (ExecutionException e) {
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// This will NEVER happen.
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throw new AssertionError("Error receiving response", e);
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} catch (InterruptedException e) {
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// The thread was interrupted, try and get the value again, this time
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// with the remaining time until the deadline.
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timeoutMillis -= deadline - System.currentTimeMillis();
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}
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}
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throw new TimeoutException();
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}
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}
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