io.grpc.ServerInterceptor Maven / Gradle / Ivy
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package io.grpc;
import javax.annotation.concurrent.ThreadSafe;
/**
* Interface for intercepting incoming calls before that are dispatched by
* {@link ServerCallHandler}.
*
* Implementers use this mechanism to add cross-cutting behavior to server-side calls. Common
* example of such behavior include:
*
* - Enforcing valid authentication credentials
* - Logging and monitoring call behavior
* - Delegating calls to other servers
*
*/
@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}.
*
* 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 method descriptor for method
* @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}.
*/
ServerCall.Listener interceptCall(
MethodDescriptor method,
ServerCall call,
Metadata.Headers headers,
ServerCallHandler next);
}