content: /*
   * 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.bookkeeper.stream.storage.impl.sc;
  
  import io.grpc.CallOptions;
  import io.grpc.Channel;
  import io.grpc.ClientCall;
  import io.grpc.Metadata;
  import io.grpc.MethodDescriptor;
  import io.grpc.Status;
  import javax.annotation.Nullable;
  
  /**
   * A channel that always throws {@link Status#NOT_FOUND}.
   */
  final class Channel404 extends Channel {
  
      static Channel404 of() {
          return INSTANCE;
      }
  
      private static final Channel404 INSTANCE = new Channel404();
  
      private static final ClientCall<Object, Object> CALL404 = new ClientCall<Object, Object>() {
          @Override
          public void start(Listener<Object> responseListener, Metadata headers) {
              responseListener.onClose(Status.NOT_FOUND, new Metadata());
          }
  
          @Override
          public void request(int numMessages) {
              // no-op
          }
  
          @Override
          public void cancel(@Nullable String message, @Nullable Throwable cause) {
              // no-op
          }
  
          @Override
          public void halfClose() {
              // no-op
          }
  
          @Override
          public void sendMessage(Object message) {
              // no-op
          }
      };
  
      private Channel404() {}
  
      @SuppressWarnings("unchecked")
      @Override
      public <RequestT, ResponseT> ClientCall<RequestT, ResponseT> newCall(
          MethodDescriptor<RequestT, ResponseT> methodDescriptor, CallOptions callOptions) {
          return (ClientCall<RequestT, ResponseT>) CALL404;
      }
  
      @Override
      public String authority() {
          return null;
      }
  }
  