content: /*
   * Copyright 2020 Alibaba Group Holding Limited.
   *
   * 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
   *
   * 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 com.alibaba.graphscope.gremlin.result;
  
  import com.alibaba.graphscope.gaia.proto.IrResult;
  import com.alibaba.graphscope.gremlin.exception.GremlinResultParserException;
  
  import org.apache.tinkerpop.gremlin.structure.Element;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.List;
  
  public enum GremlinResultParserFactory implements GremlinResultParser {
      GRAPH_ELEMENT {
          @Override
          public Object parseFrom(IrResult.Results results) {
              IrResult.Element element = ParserUtils.getHeadEntry(results).getElement();
              Object graphElement = ParserUtils.parseElement(element);
              if (!(graphElement instanceof Element || graphElement instanceof List)) {
                  throw new GremlinResultParserException(
                          "parse element should return vertex or edge or graph path");
              }
              return graphElement;
          }
      },
  
      SINGLE_VALUE {
          @Override
          public Object parseFrom(IrResult.Results results) {
              IrResult.Entry entry = ParserUtils.getHeadEntry(results);
              return ParserUtils.parseEntry(entry);
          }
      },
  
      SUBGRAPH {
          @Override
          public Object parseFrom(IrResult.Results results) {
              return EmptyValue.INSTANCE;
          }
      };
  
      private static Logger logger = LoggerFactory.getLogger(GremlinResultParserFactory.class);
  }
  