content: /*
   * Copyright 2021-2022 Alibaba Group Holding Ltd.
   *
   *    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.aliyun.fastmodel.transform.graph;
  
  import com.aliyun.fastmodel.core.tree.BaseStatement;
  import com.aliyun.fastmodel.core.tree.statement.CompositeStatement;
  import com.aliyun.fastmodel.transform.api.Transformer;
  import com.aliyun.fastmodel.transform.api.builder.BuilderFactory;
  import com.aliyun.fastmodel.transform.api.builder.StatementBuilder;
  import com.aliyun.fastmodel.transform.api.context.TransformContext;
  import com.aliyun.fastmodel.transform.api.dialect.Dialect;
  import com.aliyun.fastmodel.transform.api.dialect.DialectMeta;
  import com.aliyun.fastmodel.transform.api.dialect.DialectName;
  import com.aliyun.fastmodel.transform.api.dialect.DialectNode;
  import com.aliyun.fastmodel.transform.api.dialect.GenericDialectNode;
  import com.aliyun.fastmodel.transform.graph.context.GraphTransformContext;
  import com.aliyun.fastmodel.transform.graph.domain.FmlGraph;
  import com.aliyun.fastmodel.transform.graph.exporter.Exporter;
  import com.aliyun.fastmodel.transform.graph.exporter.ExporterFactory;
  import com.google.auto.service.AutoService;
  import com.google.common.collect.Lists;
  
  /**
   * Guava Graph的转换类
   *
   * @author panguanjing
   * @date 2021/12/12
   */
  @Dialect(DialectName.Constants.GRAPH)
  @AutoService(Transformer.class)
  public class GraphTransformer implements Transformer<BaseStatement> {
  
      @Override
      public DialectNode transform(BaseStatement source, TransformContext context) {
          boolean notCompositeStatement = source instanceof CompositeStatement;
          //convert to composite statment
          CompositeStatement compositeStatement = null;
          if (!notCompositeStatement) {
              compositeStatement = new CompositeStatement(Lists.newArrayList(source));
          } else {
              compositeStatement = (CompositeStatement)source;
          }
          StatementBuilder builder = BuilderFactory.getInstance().getBuilder(compositeStatement,
              DialectMeta.getByName(DialectName.GRAPH), context);
          GenericDialectNode<FmlGraph> genericDialectNode = builder.buildGenericNode(compositeStatement, context);
          GraphTransformContext graphTransformContext = new GraphTransformContext(context);
          Exporter exporter = ExporterFactory.getInstance().getExporter(graphTransformContext.getExportName());
          FmlGraph node = genericDialectNode.getNode();
          String graphResult = exporter.exportGraph(node);
          return new DialectNode(graphResult);
      }
  }
  