content: package org.apache.solr.search.grouping.distributed.requestfactory;
  
  /*
   * 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
   *
   *     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.
   */
  
  import org.apache.solr.common.params.CommonParams;
  import org.apache.solr.common.params.ModifiableSolrParams;
  import org.apache.solr.common.params.ShardParams;
  import org.apache.solr.handler.component.ResponseBuilder;
  import org.apache.solr.handler.component.ShardRequest;
  import org.apache.solr.search.SolrIndexSearcher;
  import org.apache.solr.search.grouping.GroupingSpecification;
  import org.apache.solr.search.grouping.distributed.ShardRequestFactory;
  
  /**
   * Concrete implementation of {@link ShardRequestFactory} that creates {@link ShardRequest} instances for getting the
   * search groups from all shards.
   */
  public class SearchGroupsRequestFactory implements ShardRequestFactory {
  
    /**
     * {@inheritDoc}
     */
    public ShardRequest[] constructRequest(ResponseBuilder rb) {
      ShardRequest sreq = new ShardRequest();
      GroupingSpecification groupingSpecification = rb.getGroupingSpec();
      if (groupingSpecification.getFields().length == 0) {
        return new ShardRequest[0];
      }
  
      sreq.purpose = ShardRequest.PURPOSE_GET_TOP_GROUPS;
  
      sreq.params = new ModifiableSolrParams(rb.req.getParams());
      // TODO: base on current params or original params?
  
      // don't pass through any shards param
      sreq.params.remove(ShardParams.SHARDS);
  
      // set the start (offset) to 0 for each shard request so we can properly merge
      // results from the start.
      if(rb.shards_start > -1) {
        // if the client set shards.start set this explicitly
        sreq.params.set(CommonParams.START,rb.shards_start);
      } else {
        sreq.params.set(CommonParams.START, "0");
      }
      // TODO: should we even use the SortSpec?  That's obtained from the QParser, and
      // perhaps we shouldn't attempt to parse the query at this level?
      // Alternate Idea: instead of specifying all these things at the upper level,
      // we could just specify that this is a shard request.
      if(rb.shards_rows > -1) {
        // if the client set shards.rows set this explicity
        sreq.params.set(CommonParams.ROWS,rb.shards_rows);
      } else {
        sreq.params.set(CommonParams.ROWS, rb.getSortSpec().getOffset() + rb.getSortSpec().getCount());
      }
  
      // in this first phase, request only the unique key field
      // and any fields needed for merging.
      sreq.params.set("group.distibuted.first","true");
  
      if ( (rb.getFieldFlags() & SolrIndexSearcher.GET_SCORES)!=0 || rb.getSortSpec().includesScore()) {
        sreq.params.set(CommonParams.FL, rb.req.getSchema().getUniqueKeyField().getName() + ",score");
      } else {
        sreq.params.set(CommonParams.FL, rb.req.getSchema().getUniqueKeyField().getName());
      }
      return new ShardRequest[] {sreq};
    }
  
  }
  