content: /**
   * Copyright 2020 Alibaba Group Holding Limited.
   *
   * <p>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
   *
   * <p>http://www.apache.org/licenses/LICENSE-2.0
   *
   * <p>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.alibaba.graphscope.groot.frontend;
  
  import com.alibaba.graphscope.groot.common.schema.api.GraphStatistics;
  import com.alibaba.graphscope.groot.common.schema.impl.DefaultGraphStatistics;
  import com.alibaba.graphscope.groot.common.schema.wrapper.GraphDef;
  import com.alibaba.graphscope.proto.groot.*;
  
  import io.grpc.stub.StreamObserver;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class FrontendSnapshotService extends FrontendSnapshotGrpc.FrontendSnapshotImplBase {
  
      private static final Logger logger = LoggerFactory.getLogger(FrontendSnapshotService.class);
  
      private final SnapshotCache snapshotCache;
  
      public FrontendSnapshotService(SnapshotCache snapshotCache) {
          this.snapshotCache = snapshotCache;
      }
  
      @Override
      public void advanceQuerySnapshot(
              AdvanceQuerySnapshotRequest request,
              StreamObserver<AdvanceQuerySnapshotResponse> observer) {
          try {
              long snapshotId = request.getSnapshotId();
              GraphDef graphDef = GraphDef.parseProto(request.getGraphDef());
              long prevSnapshotId = snapshotCache.advanceQuerySnapshotId(snapshotId, graphDef);
              AdvanceQuerySnapshotResponse response =
                      AdvanceQuerySnapshotResponse.newBuilder()
                              .setPreviousSnapshotId(prevSnapshotId)
                              .build();
              observer.onNext(response);
              observer.onCompleted();
          } catch (Exception e) {
              logger.error("error advance query snapshot", e);
              observer.onError(e);
          }
      }
  
      @Override
      public void syncStatistics(
              SyncStatisticsRequest request,
              StreamObserver<SyncStatisticsResponse> responseObserver) {
          Statistics statistics = request.getStatistics();
          GraphStatistics graphStatistics = DefaultGraphStatistics.parseProto(statistics);
          snapshotCache.setGraphStatisticsRef(graphStatistics);
          responseObserver.onNext(SyncStatisticsResponse.newBuilder().build());
          responseObserver.onCompleted();
      }
  }
  