org.apache.lucene.search.spell

## Class WordBreakSpellChecker

- java.lang.Object
- - org.apache.lucene.search.spell.WordBreakSpellChecker

-     public class WordBreakSpellChecker
      extends Object

  A spell checker whose sole function is to offer suggestions by combining multiple terms into one word and/or breaking terms into multiple words.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `WordBreakSpellChecker.BreakSuggestionSortMethod` Determines the order to list word break suggestions

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static Term` | `SEPARATOR_TERM` Term that can be used to prohibit adjacent terms from being combined

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `WordBreakSpellChecker()` Creates a new spellchecker with default configuration values

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `getMaxChanges()` Returns the maximum number of changes to perform on the input
    `int` | `getMaxCombineWordLength()` Returns the maximum length of a combined suggestion
    `int` | `getMaxEvaluations()` Returns the maximum number of word combinations to evaluate.
    `int` | `getMinBreakWordLength()` Returns the minimum size of a broken word
    `int` | `getMinSuggestionFrequency()` Returns the minimum frequency a term must have to be part of a suggestion.
    `void` | `setMaxChanges(int maxChanges)` The maximum numbers of changes (word breaks or combinations) to make on the original term(s).
    `void` | `setMaxCombineWordLength(int maxCombineWordLength)` The maximum length of a suggestion made by combining 1 or more original terms.
    `void` | `setMaxEvaluations(int maxEvaluations)` The maximum number of word combinations to evaluate.
    `void` | `setMinBreakWordLength(int minBreakWordLength)` The minimum length to break words down to.
    `void` | `setMinSuggestionFrequency(int minSuggestionFrequency)` The minimum frequency a term must have to be included as part of a suggestion.
    `SuggestWord[][]` | `suggestWordBreaks(Term term, int maxSuggestions, IndexReader ir, SuggestMode suggestMode, WordBreakSpellChecker.BreakSuggestionSortMethod sortMethod)` Generate suggestions by breaking the passed-in term into multiple words.
    `CombineSuggestion[]` | `suggestWordCombinations(Term[] terms, int maxSuggestions, IndexReader ir, SuggestMode suggestMode)` Generate suggestions by combining one or more of the passed-in terms into single words.

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

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

- - ### Field Detail

    - #### SEPARATOR_TERM

          public static final Term SEPARATOR_TERM

      Term that can be used to prohibit adjacent terms from being combined

  - ### Constructor Detail

    - #### WordBreakSpellChecker

          public WordBreakSpellChecker()

      Creates a new spellchecker with default configuration values
      See Also:
        `setMaxChanges(int)`, `setMaxCombineWordLength(int)`, `setMaxEvaluations(int)`, `setMinBreakWordLength(int)`, `setMinSuggestionFrequency(int)`

  - ### Method Detail

    - #### suggestWordBreaks

          public SuggestWord[][] suggestWordBreaks(Term term,
                                                   int maxSuggestions,
                                                   IndexReader ir,
                                                   SuggestMode suggestMode,
                                                   WordBreakSpellChecker.BreakSuggestionSortMethod sortMethod)
                                            throws IOException

      Generate suggestions by breaking the passed-in term into multiple words. The scores returned are equal to the number of word breaks needed so a lower score is generally preferred over a higher score.

      Parameters:
        `suggestMode` - - default = `SuggestMode.SUGGEST_WHEN_NOT_IN_INDEX`
        `sortMethod` - - default = `WordBreakSpellChecker.BreakSuggestionSortMethod.NUM_CHANGES_THEN_MAX_FREQUENCY`
      Returns:
        one or more arrays of words formed by breaking up the original term
      Throws:
        `IOException` - If there is a low-level I/O error.

    - #### suggestWordCombinations

          public CombineSuggestion[] suggestWordCombinations(Term[] terms,
                                                             int maxSuggestions,
                                                             IndexReader ir,
                                                             SuggestMode suggestMode)
                                                      throws IOException

      Generate suggestions by combining one or more of the passed-in terms into single words. The returned `CombineSuggestion` contains both a `SuggestWord` and also an array detailing which passed-in terms were involved in creating this combination. The scores returned are equal to the number of word combinations needed, also one less than the length of the array `CombineSuggestion.originalTermIndexes`. Generally, a suggestion with a lower score is preferred over a higher score.

      To prevent two adjacent terms from being combined (for instance, if one is mandatory and the other is prohibited), separate the two terms with `SEPARATOR_TERM`

      When suggestMode equals `SuggestMode.SUGGEST_WHEN_NOT_IN_INDEX`, each suggestion will include at least one term not in the index.

      When suggestMode equals `SuggestMode.SUGGEST_MORE_POPULAR`, each suggestion will have the same, or better frequency than the most-popular included term.

      Returns:
        an array of words generated by combining original terms
      Throws:
        `IOException` - If there is a low-level I/O error.

    - #### getMinSuggestionFrequency

          public int getMinSuggestionFrequency()

      Returns the minimum frequency a term must have to be part of a suggestion.
      See Also:
        `setMinSuggestionFrequency(int)`

    - #### getMaxCombineWordLength

          public int getMaxCombineWordLength()

      Returns the maximum length of a combined suggestion
      See Also:
        `setMaxCombineWordLength(int)`

    - #### getMinBreakWordLength

          public int getMinBreakWordLength()

      Returns the minimum size of a broken word
      See Also:
        `setMinBreakWordLength(int)`

    - #### getMaxChanges

          public int getMaxChanges()

      Returns the maximum number of changes to perform on the input
      See Also:
        `setMaxChanges(int)`

    - #### getMaxEvaluations

          public int getMaxEvaluations()

      Returns the maximum number of word combinations to evaluate.
      See Also:
        `setMaxEvaluations(int)`

    - #### setMinSuggestionFrequency

          public void setMinSuggestionFrequency(int minSuggestionFrequency)

      The minimum frequency a term must have to be included as part of a suggestion. Default=1 Not applicable when used with `SuggestMode.SUGGEST_MORE_POPULAR`

      See Also:
        `getMinSuggestionFrequency()`

    - #### setMaxCombineWordLength

          public void setMaxCombineWordLength(int maxCombineWordLength)

      The maximum length of a suggestion made by combining 1 or more original terms. Default=20

      See Also:
        `getMaxCombineWordLength()`

    - #### setMinBreakWordLength

          public void setMinBreakWordLength(int minBreakWordLength)

      The minimum length to break words down to. Default=1

      See Also:
        `getMinBreakWordLength()`

    - #### setMaxChanges

          public void setMaxChanges(int maxChanges)

      The maximum numbers of changes (word breaks or combinations) to make on the original term(s). Default=1

      See Also:
        `getMaxChanges()`

    - #### setMaxEvaluations

          public void setMaxEvaluations(int maxEvaluations)

      The maximum number of word combinations to evaluate. Default=1000. A higher value might improve result quality. A lower value might improve performance.

      See Also:
        `getMaxEvaluations()`

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