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
   * limitations under the License.
   */
  package org.apache.atlas.repository.graphdb.janus;
  
  import com.google.common.collect.Iterators;
  import org.apache.atlas.repository.graphdb.AtlasEdge;
  import org.apache.atlas.repository.graphdb.AtlasIndexQuery;
  import org.apache.atlas.repository.graphdb.AtlasVertex;
  import org.apache.tinkerpop.gremlin.process.traversal.Order;
  import org.apache.tinkerpop.gremlin.structure.Element;
  import org.janusgraph.core.JanusGraphEdge;
  import org.janusgraph.core.JanusGraphIndexQuery;
  import org.janusgraph.core.JanusGraphVertex;
  
  import java.util.Iterator;
  
  import static com.google.common.base.Preconditions.checkArgument;
  
  /**
   * Janus implementation of AtlasIndexQuery.
   */
  public class AtlasJanusIndexQuery implements AtlasIndexQuery<AtlasJanusVertex, AtlasJanusEdge> {
      private final AtlasJanusGraph      graph;
      private final JanusGraphIndexQuery query;
  
      public AtlasJanusIndexQuery(AtlasJanusGraph graph, JanusGraphIndexQuery query) {
          this.query = query;
          this.graph = graph;
      }
  
      @Override
      public Iterator<Result<AtlasJanusVertex, AtlasJanusEdge>> vertices() {
          Iterator<JanusGraphIndexQuery.Result<JanusGraphVertex>> results = query.vertexStream().iterator();
  
          return Iterators.transform(results, ResultImpl::new);
      }
  
      @Override
      public Iterator<Result<AtlasJanusVertex, AtlasJanusEdge>> vertices(int offset, int limit, String sortBy, Order sortOrder) {
          checkArgument(offset >= 0, "Index offset should be greater than or equals to 0");
          checkArgument(limit >= 0, "Index limit should be greater than or equals to 0");
  
          Iterator<JanusGraphIndexQuery.Result<JanusGraphVertex>> results = query.orderBy(sortBy, sortOrder)
                  .offset(offset)
                  .limit(limit)
                  .vertexStream().iterator();
  
          return Iterators.transform(results, ResultImpl::new);
      }
  
      @Override
      public Iterator<Result<AtlasJanusVertex, AtlasJanusEdge>> vertices(int offset, int limit) {
          checkArgument(offset >= 0, "Index offset should be greater than or equals to 0");
          checkArgument(limit >= 0, "Index limit should be greater than or equals to 0");
  
          Iterator<JanusGraphIndexQuery.Result<JanusGraphVertex>> results = query.offset(offset)
                  .limit(limit)
                  .vertexStream().iterator();
  
          return Iterators.transform(results, ResultImpl::new);
      }
  
      @Override
      public Long vertexTotals() {
          return query.offset(0).limit(Integer.MAX_VALUE).vertexTotals();
      }
  
      @Override
      public Iterator<Result<AtlasJanusVertex, AtlasJanusEdge>> edges() {
          Iterator<JanusGraphIndexQuery.Result<JanusGraphEdge>> results = query.edgeStream().iterator();
  
          return Iterators.transform(results, ResultImpl::new);
      }
  
      @Override
      public Iterator<Result<AtlasJanusVertex, AtlasJanusEdge>> edges(int offset, int limit, String sortBy, Order sortOrder) {
          checkArgument(offset >= 0, "Index offset should be greater than or equals to 0");
          checkArgument(limit >= 0, "Index limit should be greater than or equals to 0");
  
          Iterator<JanusGraphIndexQuery.Result<JanusGraphEdge>> results = query.orderBy(sortBy, sortOrder)
                  .offset(offset)
                  .limit(limit)
                  .edgeStream().iterator();
  
          return Iterators.transform(results, ResultImpl::new);
      }
  
      @Override
      public Iterator<Result<AtlasJanusVertex, AtlasJanusEdge>> edges(int offset, int limit) {
          checkArgument(offset >= 0, "Index offset should be greater than or equals to 0");
          checkArgument(limit >= 0, "Index limit should be greater than or equals to 0");
  
          Iterator<JanusGraphIndexQuery.Result<JanusGraphEdge>> results = query.offset(offset)
                  .limit(limit)
                  .edgeStream().iterator();
  
          return Iterators.transform(results, ResultImpl::new);
      }
  
      @Override
      public Long edgeTotals() {
          return query.edgeTotals();
      }
  
      /**
       * Janus implementation of AtlasIndexQuery.Result.
       */
      public final class ResultImpl implements AtlasIndexQuery.Result<AtlasJanusVertex, AtlasJanusEdge> {
          private final JanusGraphIndexQuery.Result<JanusGraphVertex> vertex;
          private final JanusGraphIndexQuery.Result<JanusGraphEdge>   edge;
  
          public ResultImpl(JanusGraphIndexQuery.Result<?> source) {
              Element element = source.getElement();
  
              if (element instanceof JanusGraphVertex) {
                  this.vertex = (JanusGraphIndexQuery.Result<JanusGraphVertex>) source;
                  this.edge   = null;
              } else if (element instanceof JanusGraphEdge) {
                  this.vertex = null;
                  this.edge   = (JanusGraphIndexQuery.Result<JanusGraphEdge>) source;
              } else {
                  this.vertex = null;
                  this.edge   = null;
              }
          }
  
          @Override
          public AtlasVertex<AtlasJanusVertex, AtlasJanusEdge> getVertex() {
              return GraphDbObjectFactory.createVertex(graph, vertex.getElement());
          }
  
          @Override
          public AtlasEdge<AtlasJanusVertex, AtlasJanusEdge> getEdge() {
              return GraphDbObjectFactory.createEdge(graph, edge.getElement());
          }
  
          @Override
          public double getScore() {
              return vertex.getScore();
          }
      }
  }
  