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.api.compare;
  
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import java.util.ServiceLoader;
  
  import com.aliyun.fastmodel.core.tree.BaseStatement;
  import com.aliyun.fastmodel.transform.api.dialect.Dialect;
  import com.aliyun.fastmodel.transform.api.dialect.DialectMeta;
  import com.aliyun.fastmodel.transform.api.dialect.DialectNode;
  
  /**
   * Node Compare Factory
   *
   * @author panguanjing
   * @date 2021/8/29
   */
  public class NodeCompareFactory {
      private static final NodeCompareFactory INSTANCE = new NodeCompareFactory();
  
      private final Map<String, NodeCompare> maps = new HashMap<>();
  
      private NodeCompareFactory() {
          ServiceLoader<NodeCompare> load = ServiceLoader.load(NodeCompare.class);
          for (NodeCompare transformer : load) {
              Dialect annotation = transformer.getClass().getAnnotation(Dialect.class);
              if (annotation != null) {
                  String dialectMeta = annotation.value() + annotation.version();
                  maps.put(dialectMeta, transformer);
              }
          }
      }
  
      public static NodeCompareFactory getInstance() {
          return INSTANCE;
      }
  
      public List<BaseStatement> compare(DialectMeta dialectMeta,
                                         String before, String after, CompareContext context) {
          CompareResult result = compareResult(dialectMeta, before, after, context);
          return result.getDiffStatements();
      }
  
      public CompareResult compareResult(DialectMeta dialectMeta,
                                         String before, String after, CompareContext context) {
          NodeCompare nodeCompare = maps.get(dialectMeta.toString());
          if (nodeCompare == null) {
              throw new UnsupportedOperationException("unsupport the dialect diff:" + dialectMeta);
          }
          return nodeCompare.compareResult(new DialectNode(before), new DialectNode(after), context);
      }
  }
  