## org.apache.lucene.index
Class FilterAtomicReader

    java.lang.Object
      org.apache.lucene.index.IndexReader
          org.apache.lucene.index.AtomicReader
              org.apache.lucene.index.FilterAtomicReader

All Implemented Interfaces:
  Closeable

    public class FilterAtomicReader

extends AtomicReader

A `FilterAtomicReader` contains another AtomicReader, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality. The class `FilterAtomicReader` itself simply implements all abstract methods of `IndexReader` with versions that pass all requests to the contained index reader. Subclasses of `FilterAtomicReader` may further override some of these methods and may also provide additional methods and fields.

NOTE: If you override `getLiveDocs()`, you will likely need to override `numDocs()` as well and vice-versa.

NOTE: If this `FilterAtomicReader` does not change the content the contained reader, you could consider overriding `IndexReader.getCoreCacheKey()` so that `FieldCache` and `CachingWrapperFilter` share the same entries for this atomic reader and the wrapped one. `IndexReader.getCombinedCoreAndDeletesKey()` could be overridden as well if the `live docs` are not changed either.

Nested Class Summary
`static class` `FilterAtomicReader.FilterDocsAndPositionsEnum` Base class for filtering `DocsAndPositionsEnum` implementations.
`static class` `FilterAtomicReader.FilterDocsEnum` Base class for filtering `DocsEnum` implementations.
`static class` `FilterAtomicReader.FilterFields` Base class for filtering `Fields` implementations.
`static class` `FilterAtomicReader.FilterTerms` Base class for filtering `Terms` implementations.
`static class` `FilterAtomicReader.FilterTermsEnum` Base class for filtering `TermsEnum` implementations.

Nested classes/interfaces inherited from class org.apache.lucene.index.IndexReader
`IndexReader.ReaderClosedListener`

Field Summary
`protected AtomicReader` `in` The underlying AtomicReader.

Constructor Summary
`FilterAtomicReader(AtomicReader in)` Construct a FilterAtomicReader based on the specified base reader.

Method Summary
`protected void` `doClose()` Implements close.
`void` `document(int docID, StoredFieldVisitor visitor)` Expert: visits the fields of a stored document, for custom processing/loading of each field.
`Fields` `fields()` Returns `Fields` for this reader.
`BinaryDocValues` `getBinaryDocValues(String field)` Returns `BinaryDocValues` for this field, or null if no `BinaryDocValues` were indexed for this field.
`FieldInfos` `getFieldInfos()` Get the `FieldInfos` describing all fields in this reader.
`Bits` `getLiveDocs()` Returns the `Bits` representing live (not deleted) docs.
`NumericDocValues` `getNormValues(String field)` Returns `NumericDocValues` representing norms for this field, or null if no `NumericDocValues` were indexed.
`NumericDocValues` `getNumericDocValues(String field)` Returns `NumericDocValues` for this field, or null if no `NumericDocValues` were indexed for this field.
`SortedDocValues` `getSortedDocValues(String field)` Returns `SortedDocValues` for this field, or null if no `SortedDocValues` were indexed for this field.
`SortedSetDocValues` `getSortedSetDocValues(String field)` Returns `SortedSetDocValues` for this field, or null if no `SortedSetDocValues` were indexed for this field.
`Fields` `getTermVectors(int docID)` Retrieve term vectors for this document, or null if term vectors were not indexed.
`int` `maxDoc()` Returns one greater than the largest possible document number.
`int` `numDocs()` Returns the number of documents in this index.
`String` `toString()`

Methods inherited from class org.apache.lucene.index.AtomicReader
`docFreq, getContext, getDocCount, getSumDocFreq, getSumTotalTermFreq, hasNorms, termDocsEnum, termPositionsEnum, terms, totalTermFreq`

Methods inherited from class org.apache.lucene.index.IndexReader
`addReaderClosedListener, close, decRef, document, document, ensureOpen, equals, getCombinedCoreAndDeletesKey, getCoreCacheKey, getRefCount, getTermVector, hasDeletions, hashCode, incRef, leaves, numDeletedDocs, open, open, open, open, open, registerParentReader, removeReaderClosedListener, tryIncRef`

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

Field Detail

### in

    protected final AtomicReader in

  The underlying AtomicReader.

Constructor Detail

### FilterAtomicReader

    public FilterAtomicReader(AtomicReader in)

  Construct a FilterAtomicReader based on the specified base reader.

  Note that base reader is closed if this FilterAtomicReader is closed.

  Parameters:
    `in` - specified base reader.

Method Detail

### getLiveDocs

    public Bits getLiveDocs()

  Description copied from class: `AtomicReader`
  Returns the `Bits` representing live (not deleted) docs. A set bit indicates the doc ID has not been deleted. If this method returns null it means there are no deleted documents (all documents are live). The returned instance has been safely published for use by multiple threads without additional synchronization.

  Specified by:
    `getLiveDocs` in class `AtomicReader`

### getFieldInfos

    public FieldInfos getFieldInfos()

  Description copied from class: `AtomicReader`
  Get the `FieldInfos` describing all fields in this reader.

  Specified by:
    `getFieldInfos` in class `AtomicReader`

### getTermVectors

    public Fields getTermVectors(int docID)
                          throws IOException

  Description copied from class: `IndexReader`
  Retrieve term vectors for this document, or null if term vectors were not indexed. The returned Fields instance acts like a single-document inverted index (the docID will be 0).

  Specified by:
    `getTermVectors` in class `IndexReader`
  Throws:
    `IOException`

### numDocs

    public int numDocs()

  Description copied from class: `IndexReader`
  Returns the number of documents in this index.

  Specified by:
    `numDocs` in class `IndexReader`

### maxDoc

    public int maxDoc()

  Description copied from class: `IndexReader`
  Returns one greater than the largest possible document number. This may be used to, e.g., determine how big to allocate an array which will have an element for every document number in an index.

  Specified by:
    `maxDoc` in class `IndexReader`

### document

    public void document(int docID,
                         StoredFieldVisitor visitor)
                  throws IOException

  Description copied from class: `IndexReader`
  Expert: visits the fields of a stored document, for custom processing/loading of each field. If you simply want to load all fields, use `IndexReader.document(int)`. If you want to load a subset, use `DocumentStoredFieldVisitor`.

  Specified by:
    `document` in class `IndexReader`
  Throws:
    `IOException`

### doClose

    protected void doClose()
                    throws IOException

  Description copied from class: `IndexReader`
  Implements close.

  Specified by:
    `doClose` in class `IndexReader`
  Throws:
    `IOException`

### fields

    public Fields fields()
                  throws IOException

  Description copied from class: `AtomicReader`
  Returns `Fields` for this reader. This method may return null if the reader has no postings.

  Specified by:
    `fields` in class `AtomicReader`
  Throws:
    `IOException`

### toString

    public String toString()

  Overrides:
    `toString` in class `Object`

### getNumericDocValues

    public NumericDocValues getNumericDocValues(String field)
                                         throws IOException

  Description copied from class: `AtomicReader`
  Returns `NumericDocValues` for this field, or null if no `NumericDocValues` were indexed for this field. The returned instance should only be used by a single thread.

  Specified by:
    `getNumericDocValues` in class `AtomicReader`
  Throws:
    `IOException`

### getBinaryDocValues

    public BinaryDocValues getBinaryDocValues(String field)
                                       throws IOException

  Description copied from class: `AtomicReader`
  Returns `BinaryDocValues` for this field, or null if no `BinaryDocValues` were indexed for this field. The returned instance should only be used by a single thread.

  Specified by:
    `getBinaryDocValues` in class `AtomicReader`
  Throws:
    `IOException`

### getSortedDocValues

    public SortedDocValues getSortedDocValues(String field)
                                       throws IOException

  Description copied from class: `AtomicReader`
  Returns `SortedDocValues` for this field, or null if no `SortedDocValues` were indexed for this field. The returned instance should only be used by a single thread.

  Specified by:
    `getSortedDocValues` in class `AtomicReader`
  Throws:
    `IOException`

### getSortedSetDocValues

    public SortedSetDocValues getSortedSetDocValues(String field)
                                             throws IOException

  Description copied from class: `AtomicReader`
  Returns `SortedSetDocValues` for this field, or null if no `SortedSetDocValues` were indexed for this field. The returned instance should only be used by a single thread.

  Specified by:
    `getSortedSetDocValues` in class `AtomicReader`
  Throws:
    `IOException`

### getNormValues

    public NumericDocValues getNormValues(String field)
                                   throws IOException

  Description copied from class: `AtomicReader`
  Returns `NumericDocValues` representing norms for this field, or null if no `NumericDocValues` were indexed. The returned instance should only be used by a single thread.

  Specified by:
    `getNormValues` in class `AtomicReader`
  Throws:
    `IOException`

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