java.lang.Object
- org.apache.lucene.index.IndexReader
- - org.apache.lucene.index.FilterIndexReader

All Implemented Interfaces:

Closeable, AutoCloseable, Cloneable

Direct Known Subclasses:

PruningReader
```
public class FilterIndexReader
extends IndexReader
```
A FilterIndexReader contains another IndexReader, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality. The class FilterIndexReader itself simply implements all abstract methods of IndexReader with versions that pass all requests to the contained index reader. Subclasses of FilterIndexReader may further override some of these methods and may also provide additional methods and fields.
Note: The default implementation of IndexReader.doOpenIfChanged() throws UnsupportedOperationException (like the base class), so it's not possible to reopen a FilterIndexReader. To reopen, you have to first reopen the underlying reader and wrap it again with the custom filter.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`FilterIndexReader.FilterTermDocs`	Base class for filtering `TermDocs` implementations.
`static class`	`FilterIndexReader.FilterTermEnum`	Base class for filtering `TermEnum` implementations.
`static class`	`FilterIndexReader.FilterTermPositions`	Base class for filtering `TermPositions` implementations.

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

Field Summary

Fields
Modifier and Type Field Description

protected IndexReader in
- Fields inherited from class org.apache.lucene.index.IndexReader
  hasChanges

Constructor Summary

Constructors
Constructor Description

FilterIndexReader(IndexReader in)
Construct a FilterIndexReader based on the specified base reader.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`Directory`	`directory()`	Returns the directory associated with this index.
`int`	`docFreq(Term t)`	Returns the number of documents containing the term `t`.
`protected void`	`doClose()`	Implements close.
`protected void`	`doCommit(Map<String,String> commitUserData)`	Deprecated.
`Document`	`document(int n, FieldSelector fieldSelector)`	Get the `Document` at the `n` ^th position.
`protected void`	`doDelete(int n)`	Deprecated.
`protected void`	`doSetNorm(int d, String f, byte b)`	Deprecated.
`protected void`	`doUndeleteAll()`	Deprecated.
`Map<String,String>`	`getCommitUserData()`	Retrieve the String userData optionally passed to IndexWriter#commit.
`Object`	`getCoreCacheKey()`	If the subclass of FilteredIndexReader modifies the contents of the FieldCache, you must override this method to provide a different key
`Object`	`getDeletesCacheKey()`	If the subclass of FilteredIndexReader modifies the deleted docs, you must override this method to provide a different key
`FieldInfos`	`getFieldInfos()`	Get the `FieldInfos` describing all fields in this reader.
`IndexCommit`	`getIndexCommit()`	Expert: return the IndexCommit that this reader has opened.
`IndexReader[]`	`getSequentialSubReaders()`	Expert: returns the sequential sub readers that this reader is logically composed of.
`TermFreqVector`	`getTermFreqVector(int docNumber, String field)`	Return a term frequency vector for the specified document and field.
`void`	`getTermFreqVector(int docNumber, String field, TermVectorMapper mapper)`	Load the Term Vector into a user-defined data structure instead of relying on the parallel arrays of the `TermFreqVector`.
`void`	`getTermFreqVector(int docNumber, TermVectorMapper mapper)`	Map all the term vectors for all fields in a Document
`TermFreqVector[]`	`getTermFreqVectors(int docNumber)`	Return an array of term frequency vectors for the specified document.
`int`	`getTermInfosIndexDivisor()`	For IndexReader implementations that use TermInfosReader to read terms, this returns the current indexDivisor as specified when the reader was opened.
`long`	`getUniqueTermCount()`	Returns the number of unique terms (across all fields) in this reader.
`long`	`getVersion()`	Version number when this IndexReader was opened.
`boolean`	`hasDeletions()`	Returns true if any documents have been deleted
`boolean`	`hasNorms(String field)`	Returns true if there are norms stored for this field.
`boolean`	`isCurrent()`	Check whether any new changes have occurred to the index since this reader was opened.
`boolean`	`isDeleted(int n)`	Returns true if document n has been deleted
`boolean`	`isOptimized()`	Deprecated.
`int`	`maxDoc()`	Returns one greater than the largest possible document number.
`byte[]`	`norms(String f)`	Returns the byte-encoded normalization factor for the named field of every document.
`void`	`norms(String f, byte[] bytes, int offset)`	Reads the byte-encoded normalization factor for the named field of every document.
`int`	`numDocs()`	Returns the number of documents in this index.
`TermDocs`	`termDocs()`	Returns an unpositioned `TermDocs` enumerator.
`TermDocs`	`termDocs(Term term)`	Returns an enumeration of all the documents which contain `term`.
`TermPositions`	`termPositions()`	Returns an unpositioned `TermPositions` enumerator.
`TermEnum`	`terms()`	Returns an enumeration of all the terms in the index.
`TermEnum`	`terms(Term t)`	Returns an enumeration of all terms starting at a given term.
`String`	`toString()`

Methods inherited from class org.apache.lucene.index.IndexReader
acquireWriteLock, addReaderClosedListener, clone, clone, close, commit, commit, decRef, deleteDocument, deleteDocuments, document, doOpenIfChanged, doOpenIfChanged, doOpenIfChanged, doOpenIfChanged, ensureOpen, flush, flush, getCommitUserData, getCurrentVersion, getRefCount, incRef, indexExists, lastModified, listCommits, numDeletedDocs, open, open, open, open, open, open, open, open, open, open, open, openIfChanged, openIfChanged, openIfChanged, openIfChanged, removeReaderClosedListener, reopen, reopen, reopen, reopen, setNorm, setNorm, termPositions, tryIncRef, undeleteAll

Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - in
```
protected IndexReader in
```
- Constructor Detail
  - FilterIndexReader
```
public FilterIndexReader(IndexReader in)
```
    Construct a FilterIndexReader based on the specified base reader. Directory locking for delete, undeleteAll, and setNorm operations is left to the base reader.
    
    Note that base reader is closed if this FilterIndexReader is closed.
    
    Parameters:
    
    in - specified base reader.
- Method Detail
  - directory
```
public Directory directory()
```
    Description copied from class: IndexReader
    
    Returns the directory associated with this index. The Default implementation returns the directory specified by subclasses when delegating to the IndexReader(Directory) constructor, or throws an UnsupportedOperationException if one was not specified.
    
    Overrides:
    
    directory in class IndexReader
  - getIndexCommit
```
public IndexCommit getIndexCommit()
                           throws IOException
```
    Description copied from class: IndexReader
    
    Expert: return the IndexCommit that this reader has opened. This method is only implemented by those readers that correspond to a Directory with its own segments_N file.
    
    Overrides:
    
    getIndexCommit in class IndexReader
    
    Throws:
    
    IOException
  - getFieldInfos
```
public FieldInfos getFieldInfos()
```
    Description copied from class: IndexReader
    
    Get the FieldInfos describing all fields in this reader. NOTE: do not make any changes to the returned FieldInfos!
    
    Specified by:
    
    getFieldInfos in class IndexReader
  - getTermInfosIndexDivisor
```
public int getTermInfosIndexDivisor()
```
    Description copied from class: IndexReader
    
    For IndexReader implementations that use TermInfosReader to read terms, this returns the current indexDivisor as specified when the reader was opened.
    
    Overrides:
    
    getTermInfosIndexDivisor in class IndexReader
  - getTermFreqVectors
```
public TermFreqVector[] getTermFreqVectors(int docNumber)
                                    throws IOException
```
    Description copied from class: IndexReader
    
    Return an array of term frequency vectors for the specified document. The array contains a vector for each vectorized field in the document. Each vector contains terms and frequencies for all terms in a given vectorized field. If no such fields existed, the method returns null. The term vectors that are returned may either be of type TermFreqVector or of type TermPositionVector if positions or offsets have been stored.
    
    Specified by:
    
    getTermFreqVectors in class IndexReader
    
    Parameters:
    
    docNumber - document for which term frequency vectors are returned
    
    Returns:
    
    array of term frequency vectors. May be null if no term vectors have been stored for the specified document.
    
    Throws:
    
    IOException - if index cannot be accessed
    
    See Also:
    
    Field.TermVector
  - getTermFreqVector
```
public TermFreqVector getTermFreqVector(int docNumber,
                                        String field)
                                 throws IOException
```
    Description copied from class: IndexReader
    
    Return a term frequency vector for the specified document and field. The returned vector contains terms and frequencies for the terms in the specified field of this document, if the field had the storeTermVector flag set. If termvectors had been stored with positions or offsets, a TermPositionVector is returned.
    
    Specified by:
    
    getTermFreqVector in class IndexReader
    
    Parameters:
    
    docNumber - document for which the term frequency vector is returned
    
    field - field for which the term frequency vector is returned.
    
    Returns:
    
    term frequency vector May be null if field does not exist in the specified document or term vector was not stored.
    
    Throws:
    
    IOException - if index cannot be accessed
    
    See Also:
    
    Field.TermVector
  - getTermFreqVector
```
public void getTermFreqVector(int docNumber,
                              String field,
                              TermVectorMapper mapper)
                       throws IOException
```
    Description copied from class: IndexReader
    
    Load the Term Vector into a user-defined data structure instead of relying on the parallel arrays of the TermFreqVector.
    
    Specified by:
    
    getTermFreqVector in class IndexReader
    
    Parameters:
    
    docNumber - The number of the document to load the vector for
    
    field - The name of the field to load
    
    mapper - The TermVectorMapper to process the vector. Must not be null
    
    Throws:
    
    IOException - if term vectors cannot be accessed or if they do not exist on the field and doc. specified.
  - getTermFreqVector
```
public void getTermFreqVector(int docNumber,
                              TermVectorMapper mapper)
                       throws IOException
```
    Description copied from class: IndexReader
    
    Map all the term vectors for all fields in a Document
    
    Specified by:
    
    getTermFreqVector in class IndexReader
    
    Parameters:
    
    docNumber - The number of the document to load the vector for
    
    mapper - The TermVectorMapper to process the vector. Must not be null
    
    Throws:
    
    IOException - if term vectors cannot be accessed or if they do not exist on the field and doc. specified.
  - getUniqueTermCount
```
public long getUniqueTermCount()
                        throws IOException
```
    Description copied from class: IndexReader
    
    Returns the number of unique terms (across all fields) in this reader. This method returns long, even though internally Lucene cannot handle more than 2^31 unique terms, for a possible future when this limitation is removed.
    
    Overrides:
    
    getUniqueTermCount 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 Document document(int n,
                         FieldSelector fieldSelector)
                  throws CorruptIndexException,
                         IOException
```
    Description copied from class: IndexReader
    
    Get the Document at the n ^th position. The FieldSelector may be used to determine what Fields to load and how they should be loaded. NOTE: If this Reader (more specifically, the underlying FieldsReader) is closed before the lazy Field is loaded an exception may be thrown. If you want the value of a lazy Field to be available after closing you must explicitly load it or fetch the Document again with a new loader.
    NOTE: for performance reasons, this method does not check if the requested document is deleted, and therefore asking for a deleted document may yield unspecified results. Usually this is not required, however you can call IndexReader.isDeleted(int) with the requested document ID to verify the document is not deleted.
    
    Specified by:
    
    document in class IndexReader
    
    Parameters:
    
    n - Get the document at the n^th position
    
    fieldSelector - The FieldSelector to use to determine what Fields should be loaded on the Document. May be null, in which case all Fields will be loaded.
    
    Returns:
    
    The stored fields of the Document at the nth position
    
    Throws:
    
    CorruptIndexException - if the index is corrupt
    
    IOException - if there is a low-level IO error
    
    See Also:
    
    Fieldable, FieldSelector, SetBasedFieldSelector, LoadFirstFieldSelector
  - isDeleted
```
public boolean isDeleted(int n)
```
    Description copied from class: IndexReader
    
    Returns true if document n has been deleted
    
    Specified by:
    
    isDeleted in class IndexReader
  - hasDeletions
```
public boolean hasDeletions()
```
    Description copied from class: IndexReader
    
    Returns true if any documents have been deleted
    
    Specified by:
    
    hasDeletions in class IndexReader
  - doUndeleteAll
```
@Deprecated
protected void doUndeleteAll()
                      throws CorruptIndexException,
                             IOException
```
    Deprecated.
    
    Implements actual undeleteAll() in subclass.
    
    Specified by:
    
    doUndeleteAll in class IndexReader
    
    Throws:
    
    CorruptIndexException
    
    IOException
  - hasNorms
```
public boolean hasNorms(String field)
                 throws IOException
```
    Description copied from class: IndexReader
    
    Returns true if there are norms stored for this field.
    
    Overrides:
    
    hasNorms in class IndexReader
    
    Throws:
    
    IOException
  - norms
```
public byte[] norms(String f)
             throws IOException
```
    Description copied from class: IndexReader
    
    Returns the byte-encoded normalization factor for the named field of every document. This is used by the search code to score documents. Returns null if norms were not indexed for this field.
    
    Specified by:
    
    norms in class IndexReader
    
    Throws:
    
    IOException
    
    See Also:
    
    AbstractField.setBoost(float)
  - norms
```
public void norms(String f,
                  byte[] bytes,
                  int offset)
           throws IOException
```
    Description copied from class: IndexReader
    
    Reads the byte-encoded normalization factor for the named field of every document. This is used by the search code to score documents.
    
    Specified by:
    
    norms in class IndexReader
    
    Throws:
    
    IOException
    
    See Also:
    
    AbstractField.setBoost(float)
  - doSetNorm
```
@Deprecated
protected void doSetNorm(int d,
                         String f,
                         byte b)
                  throws CorruptIndexException,
                         IOException
```
    Deprecated.
    
    Implements setNorm in subclass.
    
    Specified by:
    
    doSetNorm in class IndexReader
    
    Throws:
    
    CorruptIndexException
    
    IOException
  - terms
```
public TermEnum terms()
               throws IOException
```
    Description copied from class: IndexReader
    
    Returns an enumeration of all the terms in the index. The enumeration is ordered by Term.compareTo(). Each term is greater than all that precede it in the enumeration. Note that after calling terms(), TermEnum.next() must be called on the resulting enumeration before calling other methods such as TermEnum.term().
    
    Specified by:
    
    terms in class IndexReader
    
    Throws:
    
    IOException - if there is a low-level IO error
  - terms
```
public TermEnum terms(Term t)
               throws IOException
```
    Description copied from class: IndexReader
    
    Returns an enumeration of all terms starting at a given term. If the given term does not exist, the enumeration is positioned at the first term greater than the supplied term. The enumeration is ordered by Term.compareTo(). Each term is greater than all that precede it in the enumeration.
    
    Specified by:
    
    terms in class IndexReader
    
    Throws:
    
    IOException - if there is a low-level IO error
  - docFreq
```
public int docFreq(Term t)
            throws IOException
```
    Description copied from class: IndexReader
    
    Returns the number of documents containing the term t.
    
    Specified by:
    
    docFreq in class IndexReader
    
    Throws:
    
    IOException - if there is a low-level IO error
  - termDocs
```
public TermDocs termDocs()
                  throws IOException
```
    Description copied from class: IndexReader
    
    Returns an unpositioned TermDocs enumerator.
    Note: the TermDocs returned is unpositioned. Before using it, ensure that you first position it with TermDocs.seek(Term) or TermDocs.seek(TermEnum).
    
    Specified by:
    
    termDocs in class IndexReader
    
    Throws:
    
    IOException - if there is a low-level IO error
  - termDocs
```
public TermDocs termDocs(Term term)
                  throws IOException
```
    Description copied from class: IndexReader
    Returns an enumeration of all the documents which contain term. For each document, the document number, the frequency of the term in that document is also provided, for use in search scoring. If term is null, then all non-deleted docs are returned with freq=1. Thus, this method implements the mapping:
    Term => <docNum, freq>^*
    
    The enumeration is ordered by document number. Each document number is greater than all that precede it in the enumeration.
    Overrides:
    
    termDocs in class IndexReader
    
    Throws:
    
    IOException - if there is a low-level IO error
  - termPositions
```
public TermPositions termPositions()
                            throws IOException
```
    Description copied from class: IndexReader
    
    Returns an unpositioned TermPositions enumerator.
    
    Specified by:
    
    termPositions in class IndexReader
    
    Throws:
    
    IOException - if there is a low-level IO error
  - doDelete
```
@Deprecated
protected void doDelete(int n)
                 throws CorruptIndexException,
                        IOException
```
    Deprecated.
    
    Implements deletion of the document numbered docNum. Applications should call IndexReader.deleteDocument(int) or IndexReader.deleteDocuments(Term).
    
    Specified by:
    
    doDelete in class IndexReader
    
    Throws:
    
    CorruptIndexException
    
    IOException
  - doCommit
```
@Deprecated
protected void doCommit(Map<String,String> commitUserData)
                 throws IOException
```
    Deprecated.
    
    Implements commit.
    
    Specified by:
    
    doCommit 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
  - getVersion
```
public long getVersion()
```
    Description copied from class: IndexReader
    
    Version number when this IndexReader was opened. Not implemented in the IndexReader base class.
    If this reader is based on a Directory (ie, was created by calling IndexReader.open(org.apache.lucene.store.Directory), or IndexReader.openIfChanged(org.apache.lucene.index.IndexReader) on a reader based on a Directory), then this method returns the version recorded in the commit that the reader opened. This version is advanced every time IndexWriter.commit() is called.
    
    Overrides:
    
    getVersion in class IndexReader
  - isCurrent
```
public boolean isCurrent()
                  throws CorruptIndexException,
                         IOException
```
    Description copied from class: IndexReader
    
    Check whether any new changes have occurred to the index since this reader was opened.
    If this reader is based on a Directory (ie, was created by calling IndexReader.open(org.apache.lucene.store.Directory), or IndexReader.openIfChanged(org.apache.lucene.index.IndexReader) on a reader based on a Directory), then this method checks if any further commits (see IndexWriter.commit() have occurred in that directory).
    
    If instead this reader is a near real-time reader (ie, obtained by a call to IndexWriter.getReader(), or by calling IndexReader.openIfChanged(org.apache.lucene.index.IndexReader) on a near real-time reader), then this method checks if either a new commmit has occurred, or any new uncommitted changes have taken place via the writer. Note that even if the writer has only performed merging, this method will still return false.
    
    In any event, if this returns false, you should call IndexReader.openIfChanged(org.apache.lucene.index.IndexReader) to get a new reader that sees the changes.
    
    Overrides:
    
    isCurrent in class IndexReader
    
    Throws:
    
    CorruptIndexException - if the index is corrupt
    
    IOException - if there is a low-level IO error
  - isOptimized
```
@Deprecated
public boolean isOptimized()
```
    Deprecated.
    
    Overrides:
    
    isOptimized in class IndexReader
  - getSequentialSubReaders
```
public IndexReader[] getSequentialSubReaders()
```
    Description copied from class: IndexReader
    
    Expert: returns the sequential sub readers that this reader is logically composed of. For example, IndexSearcher uses this API to drive searching by one sub reader at a time. If this reader is not composed of sequential child readers, it should return null. If this method returns an empty array, that means this reader is a null reader (for example a MultiReader that has no sub readers).
    NOTE: You should not try using sub-readers returned by this method to make any changes (setNorm, deleteDocument, etc.). While this might succeed for one composite reader (like MultiReader), it will most likely lead to index corruption for other readers (like DirectoryReader obtained through IndexReader.open(org.apache.lucene.store.Directory). Use the parent reader directly.
    
    Overrides:
    
    getSequentialSubReaders in class IndexReader
  - getCommitUserData
```
public Map<String,String> getCommitUserData()
```
    Description copied from class: IndexReader
    
    Retrieve the String userData optionally passed to IndexWriter#commit. This will return null if IndexWriter.commit(Map) has never been called for this index.
    
    Overrides:
    
    getCommitUserData in class IndexReader
  - getCoreCacheKey
```
public Object getCoreCacheKey()
```
    If the subclass of FilteredIndexReader modifies the contents of the FieldCache, you must override this method to provide a different key
    
    Overrides:
    
    getCoreCacheKey in class IndexReader
  - getDeletesCacheKey
```
public Object getDeletesCacheKey()
```
    If the subclass of FilteredIndexReader modifies the deleted docs, you must override this method to provide a different key
    
    Overrides:
    
    getDeletesCacheKey in class IndexReader
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class IndexReader

Class FilterIndexReader

Nested Class Summary

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

Field Summary

Fields inherited from class org.apache.lucene.index.IndexReader

Constructor Summary

Method Summary

Methods inherited from class org.apache.lucene.index.IndexReader

Methods inherited from class java.lang.Object

Field Detail

in

Constructor Detail

FilterIndexReader

Method Detail

directory

getIndexCommit

getFieldInfos

getTermInfosIndexDivisor

getTermFreqVectors

getTermFreqVector

getTermFreqVector

getTermFreqVector

getUniqueTermCount

numDocs

maxDoc

document

isDeleted

hasDeletions

doUndeleteAll

hasNorms

norms

norms

doSetNorm

terms

terms

docFreq

termDocs

termDocs

termPositions

doDelete

doCommit

doClose

getVersion

isCurrent

isOptimized

getSequentialSubReaders

getCommitUserData

getCoreCacheKey

getDeletesCacheKey

toString