1 /* 2 * Copyright 2016 The gRPC Authors 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 io.grpc.stub; 18 19 import io.grpc.ExperimentalApi; 20 21 /** 22 * A refinement of {@link CallStreamObserver} to allows for interaction with call 23 * cancellation events on the server side. 24 * 25 * <p>Like {@code StreamObserver}, implementations are not required to be thread-safe; if multiple 26 * threads will be writing to an instance concurrently, the application must synchronize its calls. 27 * 28 * <p>DO NOT MOCK: The API is too complex to reliably mock. Use InProcessChannelBuilder to create 29 * "real" RPCs suitable for testing and interact with the server using a normal client stub. 30 */ 31 @ExperimentalApi("https://github.com/grpc/grpc-java/issues/1788") 32 public abstract class ServerCallStreamObserver<V> extends CallStreamObserver<V> { 33 34 /** 35 * If {@code true} indicates that the call has been cancelled by the remote peer. 36 * 37 * <p>This method may safely be called concurrently from multiple threads. 38 */ 39 public abstract boolean isCancelled(); 40 41 /** 42 * Set a {@link Runnable} that will be called if the calls {@link #isCancelled()} state 43 * changes from {@code false} to {@code true}. It is guaranteed that execution of the 44 * {@link Runnable} are serialized with calls to the 'inbound' {@link StreamObserver}. 45 * 46 * <p>Note that the handler may be called some time after {@link #isCancelled} has transitioned to 47 * {@code true} as other callbacks may still be executing in the 'inbound' observer. 48 * 49 * @param onCancelHandler to call when client has cancelled the call. 50 */ 51 public abstract void setOnCancelHandler(Runnable onCancelHandler); 52 53 /** 54 * Sets the compression algorithm to use for the call. May only be called before sending any 55 * messages. 56 * 57 * @param compression the compression algorithm to use. 58 */ 59 public abstract void setCompression(String compression); 60 } 61
