content: package org.apache.solr.search.grouping.distributed.command;
  
  /*
   * 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.lucene.search.Collector;
  import org.apache.lucene.search.Sort;
  import org.apache.lucene.search.grouping.SearchGroup;
  import org.apache.lucene.search.grouping.TermFirstPassGroupingCollector;
  import org.apache.solr.schema.SchemaField;
  import org.apache.solr.search.grouping.Command;
  
  import java.io.IOException;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.List;
  
  /**
   *
   */
  public class SearchGroupsFieldCommand implements Command<Collection<SearchGroup<String>>> {
  
    public static class Builder {
  
      private SchemaField field;
      private Sort groupSort;
      private Integer topNGroups;
  
      public Builder setField(SchemaField field) {
        this.field = field;
        return this;
      }
  
      public Builder setGroupSort(Sort groupSort) {
        this.groupSort = groupSort;
        return this;
      }
  
      public Builder setTopNGroups(int topNGroups) {
        this.topNGroups = topNGroups;
        return this;
      }
  
      public SearchGroupsFieldCommand build() {
        if (field == null || groupSort == null || topNGroups == null) {
          throw new IllegalStateException("All fields must be set");
        }
  
        return new SearchGroupsFieldCommand(field, groupSort, topNGroups);
      }
  
    }
  
    private final SchemaField field;
    private final Sort groupSort;
    private final int topNGroups;
  
    private TermFirstPassGroupingCollector collector;
  
    private SearchGroupsFieldCommand(SchemaField field, Sort groupSort, int topNGroups) {
      this.field = field;
      this.groupSort = groupSort;
      this.topNGroups = topNGroups;
    }
  
    public List<Collector> create() throws IOException {
      collector = new TermFirstPassGroupingCollector(field.getName(), groupSort, topNGroups);
      return Arrays.asList((Collector) collector);
    }
  
    public Collection<SearchGroup<String>> result() {
      return collector.getTopGroups(0, true);
    }
  
    public Sort getSortWithinGroup() {
      return null;
    }
  
    public Sort getGroupSort() {
      return groupSort;
    }
  
    public String getKey() {
      return field.getName();
    }
  }
  