org.apache.lucene.index

## Class FilterLeafReader.FilterTermsEnum

- java.lang.Object
- - org.apache.lucene.index.TermsEnum
  - - org.apache.lucene.index.FilterLeafReader.FilterTermsEnum

- All Implemented Interfaces:
    BytesRefIterator
  Direct Known Subclasses:
    ExitableDirectoryReader.ExitableTermsEnum
  Enclosing class:
    FilterLeafReader

      public abstract static class FilterLeafReader.FilterTermsEnum
      extends TermsEnum

  Base class for filtering `TermsEnum` implementations.

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from class org.apache.lucene.index.TermsEnum

      `TermsEnum.SeekStatus`

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected TermsEnum` | `in` The underlying TermsEnum instance.

    - ### Fields inherited from class org.apache.lucene.index.TermsEnum

      `EMPTY`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `FilterTermsEnum(TermsEnum in)` Creates a new FilterTermsEnum

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `AttributeSource` | `attributes()` Returns the related attributes.
    `int` | `docFreq()` Returns the number of documents containing the current term.
    `ImpactsEnum` | `impacts(int flags)` Return a `ImpactsEnum`.
    `BytesRef` | `next()` Increments the iteration to the next `BytesRef` in the iterator.
    `long` | `ord()` Returns ordinal position for current term.
    `PostingsEnum` | `postings(PostingsEnum reuse, int flags)` Get `PostingsEnum` for the current term, with control over whether freqs, positions, offsets or payloads are required.
    `TermsEnum.SeekStatus` | `seekCeil(BytesRef text)` Seeks to the specified term, if it exists, or to the next (ceiling) term.
    `boolean` | `seekExact(BytesRef text)` Attempts to seek to the exact term, returning true if the term is found.
    `void` | `seekExact(BytesRef term, TermState state)` Expert: Seeks a specific position by `TermState` previously obtained from `TermsEnum.termState()`.
    `void` | `seekExact(long ord)` Seeks to the specified term by ordinal (position) as previously returned by `TermsEnum.ord()`.
    `BytesRef` | `term()` Returns current term.
    `TermState` | `termState()` Expert: Returns the TermsEnums internal state to position the TermsEnum without re-seeking the term dictionary.
    `long` | `totalTermFreq()` Returns the total number of occurrences of this term across all documents (the sum of the freq() for each doc that has this term).

    - ### Methods inherited from class org.apache.lucene.index.TermsEnum

      `postings`

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

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

- - ### Field Detail

    - #### in

          protected final TermsEnum in

      The underlying TermsEnum instance.

  - ### Constructor Detail

    - #### FilterTermsEnum

          public FilterTermsEnum(TermsEnum in)

      Creates a new FilterTermsEnum
      Parameters:
        `in` - the underlying TermsEnum instance.

  - ### Method Detail

    - #### attributes

          public AttributeSource attributes()

      Description copied from class: `TermsEnum`
      Returns the related attributes.
      Specified by:
        `attributes` in class `TermsEnum`

    - #### seekCeil

          public TermsEnum.SeekStatus seekCeil(BytesRef text)
                                        throws IOException

      Description copied from class: `TermsEnum`
      Seeks to the specified term, if it exists, or to the next (ceiling) term. Returns SeekStatus to indicate whether exact term was found, a different term was found, or EOF was hit. The target term may be before or after the current term. If this returns SeekStatus.END, the enum is unpositioned.
      Specified by:
        `seekCeil` in class `TermsEnum`
      Throws:
        `IOException`

    - #### seekExact

          public boolean seekExact(BytesRef text)
                            throws IOException

      Description copied from class: `TermsEnum`
      Attempts to seek to the exact term, returning true if the term is found. If this returns false, the enum is unpositioned. For some codecs, seekExact may be substantially faster than `TermsEnum.seekCeil(org.apache.lucene.util.BytesRef)`.
      Specified by:
        `seekExact` in class `TermsEnum`
      Returns:
        true if the term is found; return false if the enum is unpositioned.
      Throws:
        `IOException`

    - #### seekExact

          public void seekExact(long ord)
                         throws IOException

      Description copied from class: `TermsEnum`
      Seeks to the specified term by ordinal (position) as previously returned by `TermsEnum.ord()`. The target ord may be before or after the current ord, and must be within bounds.
      Specified by:
        `seekExact` in class `TermsEnum`
      Throws:
        `IOException`

    - #### next

          public BytesRef next()
                        throws IOException

      Description copied from interface: `BytesRefIterator`
      Increments the iteration to the next `BytesRef` in the iterator. Returns the resulting `BytesRef` or `null` if the end of the iterator is reached. The returned BytesRef may be re-used across calls to next. After this method returns null, do not call it again: the results are undefined.
      Returns:
        the next `BytesRef` in the iterator or `null` if the end of the iterator is reached.
      Throws:
        `IOException` - If there is a low-level I/O error.

    - #### term

          public BytesRef term()
                        throws IOException

      Description copied from class: `TermsEnum`
      Returns current term. Do not call this when the enum is unpositioned.
      Specified by:
        `term` in class `TermsEnum`
      Throws:
        `IOException`

    - #### ord

          public long ord()
                   throws IOException

      Description copied from class: `TermsEnum`
      Returns ordinal position for current term. This is an optional method (the codec may throw `UnsupportedOperationException`). Do not call this when the enum is unpositioned.
      Specified by:
        `ord` in class `TermsEnum`
      Throws:
        `IOException`

    - #### docFreq

          public int docFreq()
                      throws IOException

      Description copied from class: `TermsEnum`
      Returns the number of documents containing the current term. Do not call this when the enum is unpositioned. `TermsEnum.SeekStatus.END`.
      Specified by:
        `docFreq` in class `TermsEnum`
      Throws:
        `IOException`

    - #### totalTermFreq

          public long totalTermFreq()
                             throws IOException

      Description copied from class: `TermsEnum`
      Returns the total number of occurrences of this term across all documents (the sum of the freq() for each doc that has this term). Note that, like other term measures, this measure does not take deleted documents into account.
      Specified by:
        `totalTermFreq` in class `TermsEnum`
      Throws:
        `IOException`

    - #### postings

          public PostingsEnum postings(PostingsEnum reuse,
                                       int flags)
                                throws IOException

      Description copied from class: `TermsEnum`
      Get `PostingsEnum` for the current term, with control over whether freqs, positions, offsets or payloads are required. Do not call this when the enum is unpositioned. This method will not return null.

      NOTE: the returned iterator may return deleted documents, so deleted documents have to be checked on top of the `PostingsEnum`.

      Specified by:
        `postings` in class `TermsEnum`
      Parameters:
        `reuse` - pass a prior PostingsEnum for possible reuse
        `flags` - specifies which optional per-document values you require; see `PostingsEnum.FREQS`
      Throws:
        `IOException`

    - #### impacts

          public ImpactsEnum impacts(int flags)
                              throws IOException

      Description copied from class: `TermsEnum`
      Return a `ImpactsEnum`.
      Specified by:
        `impacts` in class `TermsEnum`
      Throws:
        `IOException`
      See Also:
        `TermsEnum.postings(PostingsEnum, int)`

    - #### seekExact

          public void seekExact(BytesRef term,
                                TermState state)
                         throws IOException

      Description copied from class: `TermsEnum`
      Expert: Seeks a specific position by `TermState` previously obtained from `TermsEnum.termState()`. Callers should maintain the `TermState` to use this method. Low-level implementations may position the TermsEnum without re-seeking the term dictionary.

      Seeking by `TermState` should only be used iff the state was obtained from the same `TermsEnum` instance.

      NOTE: Using this method with an incompatible `TermState` might leave this `TermsEnum` in undefined state. On a segment level `TermState` instances are compatible only iff the source and the target `TermsEnum` operate on the same field. If operating on segment level, TermState instances must not be used across segments.

      NOTE: A seek by `TermState` might not restore the `AttributeSource`'s state. `AttributeSource` states must be maintained separately if this method is used.

      Specified by:
        `seekExact` in class `TermsEnum`
      Parameters:
        `term` - the term the TermState corresponds to
        `state` - the `TermState`
      Throws:
        `IOException`

    - #### termState

          public TermState termState()
                              throws IOException

      Description copied from class: `TermsEnum`
      Expert: Returns the TermsEnums internal state to position the TermsEnum without re-seeking the term dictionary.

      NOTE: A seek by `TermState` might not capture the `AttributeSource`'s state. Callers must maintain the `AttributeSource` states separately

      Specified by:
        `termState` in class `TermsEnum`
      Throws:
        `IOException`
      See Also:
        `TermState`, `TermsEnum.seekExact(BytesRef, TermState)`

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