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.impala.hooks;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * {@link QueryCompleteContext} encapsulates immutable information sent from the
   * BE to a post-query hook.
   */
  public class QueryCompleteContext {
      private final String lineageGraphObject;
  
      public QueryCompleteContext(String lineageGraph) {
          lineageGraphObject = requireNonNull(lineageGraph);
      }
  
      /**
       * Returns the lineage graph sent from the backend during
       * {@link QueryEventHook#onQueryComplete(QueryCompleteContext)}.  This graph
       * object will generally contain more information than it did when it was
       * first constructed in the frontend, because the backend will have filled
       * in additional information.
       * <p>
       * The returned object is a JSON representation of the lineage graph object
       * for the query.  The details of the JSON translation are not provided here
       * as this is meant to be a temporary feature, and the String format will
       * be changed to something more strongly-typed in the future.
       * </p>
       *
       * @return lineage graph from the query that executed
       */
      public String getLineageGraph() {
          return lineageGraphObject;
      }
  
      @Override
      public String toString() {
          return "QueryCompleteContext{" +
              "lineageGraph='" + lineageGraphObject + '\'' +
              '}';
      }
  }
  