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
   * <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
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  package org.apache.atlas.repository.store.graph.v2;
  
  import org.apache.atlas.AtlasErrorCode;
  import org.apache.atlas.RequestContext;
  import org.apache.atlas.exception.AtlasBaseException;
  import org.apache.atlas.model.TypeCategory;
  import org.apache.atlas.model.instance.AtlasObjectId;
  import org.apache.atlas.repository.graphdb.AtlasGraph;
  import org.apache.atlas.repository.graphdb.AtlasVertex;
  import org.apache.atlas.repository.store.graph.EntityGraphDiscoveryContext;
  import org.apache.atlas.repository.store.graph.EntityResolver;
  import org.apache.atlas.type.AtlasEntityType;
  import org.apache.atlas.type.AtlasTypeRegistry;
  
  import java.util.ArrayList;
  import java.util.List;
  
  public class UniqAttrBasedEntityResolver implements EntityResolver {
      private final AtlasGraph        graph;
      private final AtlasTypeRegistry typeRegistry;
      private final EntityGraphMapper entityGraphMapper;
  
      public UniqAttrBasedEntityResolver(AtlasGraph graph, AtlasTypeRegistry typeRegistry, EntityGraphMapper entityGraphMapper) {
          this.graph             = graph;
          this.typeRegistry      = typeRegistry;
          this.entityGraphMapper = entityGraphMapper;
      }
  
      @Override
      public EntityGraphDiscoveryContext resolveEntityReferences(EntityGraphDiscoveryContext context) throws AtlasBaseException {
          if (context == null) {
              throw new AtlasBaseException(AtlasErrorCode.INTERNAL_ERROR, "UniqAttrBasedEntityResolver.resolveEntityReferences(): context is null");
          }
  
          //Resolve attribute references
          List<AtlasObjectId> resolvedReferences = new ArrayList<>();
  
          for (AtlasObjectId objId : context.getReferencedByUniqAttribs()) {
              //query in graph repo that given unique attribute - check for deleted also?
              AtlasEntityType entityType = typeRegistry.getEntityTypeByName(objId.getTypeName());
  
              if (entityType == null) {
                  throw new AtlasBaseException(AtlasErrorCode.TYPE_NAME_INVALID, TypeCategory.ENTITY.name(), objId.getTypeName());
              }
  
              AtlasVertex vertex = AtlasGraphUtilsV2.findByUniqueAttributes(this.graph, entityType, objId.getUniqueAttributes());
  
              if (vertex == null && RequestContext.get().isCreateShellEntityForNonExistingReference()) {
                  vertex = entityGraphMapper.createShellEntityVertex(objId, context);
              }
  
              if (vertex != null) {
                  context.addResolvedIdByUniqAttribs(objId, vertex);
                  resolvedReferences.add(objId);
              } else {
                  throw new AtlasBaseException(AtlasErrorCode.REFERENCED_ENTITY_NOT_FOUND, objId.toString());
              }
          }
  
          return context;
      }
  }
  