org.apache.lucene.util

## Class IntroSorter

- java.lang.Object
- - org.apache.lucene.util.Sorter
  - - org.apache.lucene.util.IntroSorter

-     public abstract class IntroSorter
      extends Sorter

  `Sorter` implementation based on a variant of the quicksort algorithm called introsort: when the recursion level exceeds the log of the length of the array to sort, it falls back to heapsort. This prevents quicksort from running into its worst-case quadratic runtime. Small arrays are sorted with insertion sort.
  NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `IntroSorter()` Create a new `IntroSorter`.

  - ### Method Summary

    All Methods Instance Methods Abstract Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `protected int` | `compare(int i, int j)` Compare entries found in slots `i` and `j`.
    `protected abstract int` | `comparePivot(int j)` Compare the pivot with the slot at `j`, similarly to `compare(i, j)`.
    `protected abstract void` | `setPivot(int i)` Save the value at slot `i` so that it can later be used as a pivot, see `Sorter.comparePivot(int)`.
    `void` | `sort(int from, int to)` Sort the slice which starts at `from` (inclusive) and ends at `to` (exclusive).

    - ### Methods inherited from class org.apache.lucene.util.Sorter

      `swap`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### IntroSorter

          public IntroSorter()

      Create a new `IntroSorter`.

  - ### Method Detail

    - #### sort

          public final void sort(int from,
                                 int to)

      Description copied from class: `Sorter`
      Sort the slice which starts at `from` (inclusive) and ends at `to` (exclusive).
      Specified by:
        `sort` in class `Sorter`

    - #### setPivot

          protected abstract void setPivot(int i)

      Description copied from class: `Sorter`
      Save the value at slot `i` so that it can later be used as a pivot, see `Sorter.comparePivot(int)`.
      Overrides:
        `setPivot` in class `Sorter`

    - #### comparePivot

          protected abstract int comparePivot(int j)

      Description copied from class: `Sorter`
      Compare the pivot with the slot at `j`, similarly to `compare(i, j)`.
      Overrides:
        `comparePivot` in class `Sorter`

    - #### compare

          protected int compare(int i,
                                int j)

      Description copied from class: `Sorter`
      Compare entries found in slots `i` and `j`. The contract for the returned value is the same as `Comparator.compare(Object, Object)`.
      Specified by:
        `compare` in class `Sorter`

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