ServerBackpressureThresholdInterceptor.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.arrow.flight.grpc;

import io.grpc.Metadata;
import io.grpc.ServerCall;
import io.grpc.ServerCallHandler;
import io.grpc.ServerInterceptor;

/**
 * An interceptor for specifying the number of bytes that can be queued before a call with an output
 * stream gets blocked by backpressure.
 */
public class ServerBackpressureThresholdInterceptor implements ServerInterceptor {

  private final int numBytes;

  public ServerBackpressureThresholdInterceptor(int numBytes) {
    this.numBytes = numBytes;
  }

  @Override
  public <ReqT, RespT> ServerCall.Listener<ReqT> interceptCall(
      ServerCall<ReqT, RespT> call, Metadata headers, ServerCallHandler<ReqT, RespT> next) {
    call.setOnReadyThreshold(numBytes);
    return next.startCall(call, headers);
  }
}