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.beam.runners.dataflow.worker.windmill.client.getdata;
  
  import java.io.PrintWriter;
  import org.apache.beam.runners.dataflow.worker.windmill.Windmill.GlobalData;
  import org.apache.beam.runners.dataflow.worker.windmill.Windmill.GlobalDataRequest;
  import org.apache.beam.runners.dataflow.worker.windmill.Windmill.KeyedGetDataRequest;
  import org.apache.beam.runners.dataflow.worker.windmill.Windmill.KeyedGetDataResponse;
  import org.apache.beam.sdk.annotations.Internal;
  
  /** Client for streaming backend GetData API. */
  @Internal
  public interface GetDataClient {
    /**
     * Issues a blocking call to fetch state data for a specific computation and {@link
     * org.apache.beam.runners.dataflow.worker.windmill.Windmill.WorkItem}.
     *
     * @throws GetDataException when there was an unexpected error during the attempted fetch.
     */
    KeyedGetDataResponse getStateData(String computationId, KeyedGetDataRequest request)
        throws GetDataException;
  
    /**
     * Issues a blocking call to fetch side input data.
     *
     * @throws GetDataException when there was an unexpected error during the attempted fetch.
     */
    GlobalData getSideInputData(GlobalDataRequest request) throws GetDataException;
  
    void printHtml(PrintWriter writer);
  
    final class GetDataException extends RuntimeException {
      GetDataException(String message, Throwable cause) {
        super(message, cause);
      }
  
      GetDataException(String message) {
        super(message);
      }
    }
  }
  