org.apache.lucene.search.grouping.term

## Class TermAllGroupsCollector

- java.lang.Object
- - org.apache.lucene.search.SimpleCollector
  - - org.apache.lucene.search.grouping.AllGroupsCollector<BytesRef>
    - - org.apache.lucene.search.grouping.term.TermAllGroupsCollector

- All Implemented Interfaces:
    Collector, LeafCollector

      public class TermAllGroupsCollector
      extends AllGroupsCollector<BytesRef>

  A collector that collects all groups that match the query. Only the group value is collected, and the order is undefined. This collector does not determine the most relevant document of a group.

  Implementation detail: an int hash set (SentinelIntSet) is used to detect if a group is already added to the total count. For each segment the int set is cleared and filled with previous counted groups that occur in the new segment.

  WARNING: This API is experimental and might change in incompatible ways in the next release.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `TermAllGroupsCollector(String groupField)` Constructs a `AllGroupsCollector`.
    `TermAllGroupsCollector(String groupField, int initialSize)` Expert: Constructs a `AllGroupsCollector`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `collect(int doc)`
    `protected void` | `doSetNextReader(LeafReaderContext context)`
    `Collection<BytesRef>` | `getGroups()` Returns the group values

    - ### Methods inherited from class org.apache.lucene.search.grouping.AllGroupsCollector

      `getGroupCount, needsScores, setScorer`

    - ### 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`

- - ### Constructor Detail

    - #### TermAllGroupsCollector

          public TermAllGroupsCollector(String groupField,
                                        int initialSize)

      Expert: Constructs a `AllGroupsCollector`
      Parameters:
        `groupField` - The field to group by
        `initialSize` - The initial allocation size of the internal int set and group list which should roughly match the total number of expected unique groups. Be aware that the heap usage is 4 bytes * initialSize.

    - #### TermAllGroupsCollector

          public TermAllGroupsCollector(String groupField)

      Constructs a `AllGroupsCollector`. This sets the initial allocation size for the internal int set and group list to 128.
      Parameters:
        `groupField` - The field to group by

  - ### Method Detail

    - #### collect

          public void collect(int doc)
                       throws IOException

      Specified by:
        `collect` in interface `LeafCollector`
      Specified by:
        `collect` in class `SimpleCollector`
      Throws:
        `IOException`

    - #### getGroups

          public Collection<BytesRef> getGroups()

      Description copied from class: `AllGroupsCollector`
      Returns the group values

      This is an unordered collections of group values. For each group that matched the query there is a `BytesRef` representing a group value.

      Specified by:
        `getGroups` in class `AllGroupsCollector<BytesRef>`
      Returns:
        the group values

    - #### doSetNextReader

          protected void doSetNextReader(LeafReaderContext context)
                                  throws IOException

      Overrides:
        `doSetNextReader` in class `SimpleCollector`
      Throws:
        `IOException`

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