org.apache.lucene.search

## Class PhraseQuery

- java.lang.Object
- - org.apache.lucene.search.Query
  - - org.apache.lucene.search.PhraseQuery

- All Implemented Interfaces:
    Cloneable
  Direct Known Subclasses:
    NGramPhraseQuery

      public class PhraseQuery
      extends Query

  A Query that matches documents containing a particular sequence of terms. A PhraseQuery is built by QueryParser for input like `"new york"`.

  This query may be combined with other terms or queries with a `BooleanQuery`.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `PhraseQuery()` Constructs an empty phrase query.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `add(Term term)` Adds a term to the end of the query phrase.
    `void` | `add(Term term, int position)` Adds a term to the end of the query phrase.
    `Weight` | `createWeight(IndexSearcher searcher)` Expert: Constructs an appropriate Weight implementation for this query.
    `boolean` | `equals(Object o)` Returns true iff `o` is equal to this.
    `void` | `extractTerms(Set<Term> queryTerms)` Expert: adds all terms occurring in this query to the terms set.
    `int[]` | `getPositions()` Returns the relative positions of terms in this phrase.
    `int` | `getSlop()` Returns the slop.
    `Term[]` | `getTerms()` Returns the set of terms in this phrase.
    `int` | `hashCode()` Returns a hash code value for this object.
    `Query` | `rewrite(IndexReader reader)` Expert: called to re-write queries into primitive queries.
    `void` | `setSlop(int s)` Sets the number of other words permitted between words in query phrase.
    `String` | `toString(String f)` Prints a user-readable version of this query.

    - ### Methods inherited from class org.apache.lucene.search.Query

      `clone, getBoost, setBoost, toString`

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

      `finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### PhraseQuery

          public PhraseQuery()

      Constructs an empty phrase query.

  - ### Method Detail

    - #### setSlop

          public void setSlop(int s)

      Sets the number of other words permitted between words in query phrase. If zero, then this is an exact phrase search. For larger values this works like a `WITHIN` or `NEAR` operator.

      The slop is in fact an edit-distance, where the units correspond to moves of terms in the query phrase out of position. For example, to switch the order of two words requires two moves (the first move places the words atop one another), so to permit re-orderings of phrases, the slop must be at least two.

      More exact matches are scored higher than sloppier matches, thus search results are sorted by exactness.

      The slop is zero by default, requiring exact matches.

    - #### getSlop

          public int getSlop()

      Returns the slop. See setSlop().

    - #### add

          public void add(Term term)

      Adds a term to the end of the query phrase. The relative position of the term is the one immediately after the last term added.

    - #### add

          public void add(Term term,
                 int position)

      Adds a term to the end of the query phrase. The relative position of the term within the phrase is specified explicitly. This allows e.g. phrases with more than one term at the same position or phrases with gaps (e.g. in connection with stopwords).

    - #### getTerms

          public Term[] getTerms()

      Returns the set of terms in this phrase.

    - #### getPositions

          public int[] getPositions()

      Returns the relative positions of terms in this phrase.

    - #### rewrite

          public Query rewrite(IndexReader reader)
                        throws IOException

      Description copied from class: `Query`
      Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.
      Overrides:
        `rewrite` in class `Query`
      Throws:
        `IOException`

    - #### createWeight

          public Weight createWeight(IndexSearcher searcher)
                              throws IOException

      Description copied from class: `Query`
      Expert: Constructs an appropriate Weight implementation for this query.

      Only implemented by primitive queries, which re-write to themselves.

      Overrides:
        `createWeight` in class `Query`
      Throws:
        `IOException`

    - #### extractTerms

          public void extractTerms(Set<Term> queryTerms)

      Description copied from class: `Query`
      Expert: adds all terms occurring in this query to the terms set. Only works if this query is in its `rewritten` form.
      Overrides:
        `extractTerms` in class `Query`
      See Also:
        `Query.extractTerms(Set)`

    - #### toString

          public String toString(String f)

      Prints a user-readable version of this query.
      Specified by:
        `toString` in class `Query`

    - #### equals

          public boolean equals(Object o)

      Returns true iff `o` is equal to this.
      Overrides:
        `equals` in class `Query`

    - #### hashCode

          public int hashCode()

      Returns a hash code value for this object.
      Overrides:
        `hashCode` in class `Query`

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