Class CollapsingTopDocsCollector<T>

  • All Implemented Interfaces:
    org.apache.lucene.search.Collector, org.apache.lucene.search.LeafCollector

    public final class CollapsingTopDocsCollector<T>
    extends org.apache.lucene.search.grouping.FirstPassGroupingCollector<T>
    A collector that groups documents based on field values and returns CollapseTopFieldDocs output. The collapsing is done in a single pass by selecting only the top sorted document per collapse key. The value used for the collapse key of each group can be found in CollapseTopFieldDocs.collapseValues. TODO: If the sort is based on score we should propagate the mininum competitive score when orderedGroups is full. This is safe for collapsing since the group sort is the same as the query sort.
    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected java.lang.String collapseField  
      protected org.apache.lucene.search.Scorable scorer  
      protected org.apache.lucene.search.Sort sort  
      • Fields inherited from class org.apache.lucene.search.grouping.FirstPassGroupingCollector

        orderedGroups
    • Method Summary

      Modifier and Type Method Description
      void collect​(int doc)  
      static CollapsingTopDocsCollector<?> createKeyword​(java.lang.String collapseField, MappedFieldType collapseFieldType, org.apache.lucene.search.Sort sort, int topN)
      Create a collapsing top docs collector on a SortedDocValues field.
      static CollapsingTopDocsCollector<?> createNumeric​(java.lang.String collapseField, MappedFieldType collapseFieldType, org.apache.lucene.search.Sort sort, int topN)
      Create a collapsing top docs collector on a NumericDocValues field.
      CollapseTopFieldDocs getTopDocs()
      Transform FirstPassGroupingCollector.getTopGroups(int) output in CollapseTopFieldDocs.
      org.apache.lucene.search.ScoreMode scoreMode()  
      void setScorer​(org.apache.lucene.search.Scorable scorer)  
      • Methods inherited from class org.apache.lucene.search.grouping.FirstPassGroupingCollector

        doSetNextReader, getGroupSelector, getTopGroups
      • Methods inherited from class org.apache.lucene.search.SimpleCollector

        getLeafCollector
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • collapseField

        protected final java.lang.String collapseField
      • sort

        protected final org.apache.lucene.search.Sort sort
      • scorer

        protected org.apache.lucene.search.Scorable scorer
    • Method Detail

      • getTopDocs

        public CollapseTopFieldDocs getTopDocs()
                                        throws java.io.IOException
        Transform FirstPassGroupingCollector.getTopGroups(int) output in CollapseTopFieldDocs. The collapsing needs only one pass so we can get the final top docs at the end of the first pass.
        Throws:
        java.io.IOException
      • scoreMode

        public org.apache.lucene.search.ScoreMode scoreMode()
        Specified by:
        scoreMode in interface org.apache.lucene.search.Collector
        Overrides:
        scoreMode in class org.apache.lucene.search.grouping.FirstPassGroupingCollector<T>
      • setScorer

        public void setScorer​(org.apache.lucene.search.Scorable scorer)
                       throws java.io.IOException
        Specified by:
        setScorer in interface org.apache.lucene.search.LeafCollector
        Overrides:
        setScorer in class org.apache.lucene.search.grouping.FirstPassGroupingCollector<T>
        Throws:
        java.io.IOException
      • collect

        public void collect​(int doc)
                     throws java.io.IOException
        Specified by:
        collect in interface org.apache.lucene.search.LeafCollector
        Overrides:
        collect in class org.apache.lucene.search.grouping.FirstPassGroupingCollector<T>
        Throws:
        java.io.IOException
      • createNumeric

        public static CollapsingTopDocsCollector<?> createNumeric​(java.lang.String collapseField,
                                                                  MappedFieldType collapseFieldType,
                                                                  org.apache.lucene.search.Sort sort,
                                                                  int topN)
        Create a collapsing top docs collector on a NumericDocValues field. It accepts also SortedNumericDocValues field but the collect will fail with an IllegalStateException if a document contains more than one value for the field.
        Parameters:
        collapseField - The sort field used to group documents.
        collapseFieldType - The MappedFieldType for this sort field.
        sort - The Sort used to sort the collapsed hits. The collapsing keeps only the top sorted document per collapsed key. This must be non-null, ie, if you want to groupSort by relevance use Sort.RELEVANCE.
        topN - How many top groups to keep.
      • createKeyword

        public static CollapsingTopDocsCollector<?> createKeyword​(java.lang.String collapseField,
                                                                  MappedFieldType collapseFieldType,
                                                                  org.apache.lucene.search.Sort sort,
                                                                  int topN)
        Create a collapsing top docs collector on a SortedDocValues field. It accepts also SortedSetDocValues field but the collect will fail with an IllegalStateException if a document contains more than one value for the field.
        Parameters:
        collapseField - The sort field used to group documents.
        collapseFieldType - The MappedFieldType for this sort field.
        sort - The Sort used to sort the collapsed hits. The collapsing keeps only the top sorted document per collapsed key. This must be non-null, ie, if you want to groupSort by relevance use Sort.RELEVANCE.
        topN - How many top groups to keep.