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/*
* Copyright 2014 The gRPC Authors
*
* 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 com.couchbase.client.core.deps.io.grpc;
import javax.annotation.concurrent.ThreadSafe;
/**
* Interface to initiate processing of incoming remote calls. Advanced applications and generated
* code will implement this interface to allows {@link Server}s to invoke service methods.
*/
@ThreadSafe
public interface ServerCallHandler {
/**
* Starts asynchronous processing of an incoming call.
*
* Callers of this method transfer their ownership of the non-thread-safe {@link ServerCall}
* and {@link Metadata} arguments to the {@link ServerCallHandler} implementation for processing.
* Ownership means that the implementation may invoke methods on {@code call} and {@code headers}
* while {@link #startCall} runs and at any time after it returns normally. On the other hand, if
* {@link #startCall} throws, ownership of {@code call} and {@code headers} reverts to the caller
* and the implementation loses the right to call methods on these objects (from some other
* thread, say).
*
*
Ownership also includes the responsibility to eventually close {@code call}. In particular,
* if {@link #startCall} throws an exception, the caller must handle it by closing {@code call}
* with an error. Since {@code call} can only be closed once, an implementation can report errors
* either to {@link ServerCall#close} for itself or by throwing an exception, but not both.
*
*
Returns a non-{@code null} listener for the incoming call. Callers of this method must
* arrange for events associated with {@code call} to be delivered there.
*
* @param call object for responding to the remote client.
* @param headers request headers received from the client but open to modification by an owner
* @return listener for processing incoming request messages for {@code call}
*/
ServerCall.Listener startCall(
ServerCall call,
Metadata headers);
}