| /* |
| * Copyright 2014, gRPC Authors All rights reserved. |
| * |
| * 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 io.grpc; |
| |
| import javax.annotation.concurrent.ThreadSafe; |
| |
| /** |
| * Interface for intercepting incoming calls before that are dispatched by |
| * {@link ServerCallHandler}. |
| * |
| * <p>Implementers use this mechanism to add cross-cutting behavior to server-side calls. Common |
| * example of such behavior include: |
| * <ul> |
| * <li>Enforcing valid authentication credentials</li> |
| * <li>Logging and monitoring call behavior</li> |
| * <li>Delegating calls to other servers</li> |
| * </ul> |
| */ |
| @ThreadSafe |
| public interface ServerInterceptor { |
| /** |
| * Intercept {@link ServerCall} dispatch by the {@code next} {@link ServerCallHandler}. General |
| * semantics of {@link ServerCallHandler#startCall} apply and the returned |
| * {@link io.grpc.ServerCall.Listener} must not be {@code null}. |
| * |
| * <p>If the implementation throws an exception, {@code call} will be closed with an error. |
| * Implementations must not throw an exception if they started processing that may use {@code |
| * call} on another thread. |
| * |
| * @param call object to receive response messages |
| * @param next next processor in the interceptor chain |
| * @return listener for processing incoming messages for {@code call}, never {@code null}. |
| */ |
| <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall( |
| ServerCall<ReqT, RespT> call, |
| Metadata headers, |
| ServerCallHandler<ReqT, RespT> next); |
| } |