1 /* 2 * Copyright 2014 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; 18 19 import javax.annotation.concurrent.ThreadSafe; 20 21 /** 22 * Interface to initiate processing of incoming remote calls. Advanced applications and generated 23 * code will implement this interface to allows {@link Server}s to invoke service methods. 24 */ 25 @ThreadSafe 26 public interface ServerCallHandler<RequestT, ResponseT> { 27 /** 28 * Produce a non-{@code null} listener for the incoming call. Implementations are free to call 29 * methods on {@code call} before this method has returned. 30 * 31 * <p>Since {@link Metadata} is not thread-safe, the caller must not access (read or write) {@code 32 * headers} after this point. 33 * 34 * <p>If the implementation throws an exception, {@code call} will be closed with an error. 35 * Implementations must not throw an exception if they started processing that may use {@code 36 * call} on another thread. 37 * 38 * @param call object for responding to the remote client. 39 * @return listener for processing incoming request messages for {@code call} 40 */ startCall( ServerCall<RequestT, ResponseT> call, Metadata headers)41 ServerCall.Listener<RequestT> startCall( 42 ServerCall<RequestT, ResponseT> call, 43 Metadata headers); 44 } 45