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.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
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

Fields

Modifier and Type	Field and Description
protected AtomicReader	in The underlying AtomicReader.

Constructor Summary

Constructors

Constructor and Description
FilterAtomicReader(AtomicReader in) Construct a FilterAtomicReader based on the specified base reader.

Method Summary

Methods

Modifier and Type	Method and Description
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.
DocValues	docValues(String field) Returns DocValues for this field.
Fields	fields() Returns Fields for this reader.
Object	getCombinedCoreAndDeletesKey() Expert: Returns a key for this IndexReader that also includes deletions, so FieldCache/CachingWrapperFilter can find it again.
Object	getCoreCacheKey() Expert: Returns a key for this IndexReader, so FieldCache/CachingWrapperFilter can find it again.
FieldInfos	getFieldInfos() Get the FieldInfos describing all fields in this reader.
Bits	getLiveDocs() Returns the Bits representing live (not deleted) docs.
Fields	getTermVectors(int docID) Retrieve term vectors for this document, or null if term vectors were not indexed.
boolean	hasDeletions() Returns true if any documents have been deleted
int	maxDoc() Returns one greater than the largest possible document number.
DocValues	normValues(String field) Returns DocValues for this field's normalization values.
int	numDocs() Returns the number of documents in this index.
String	toString()

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

docFreq, getContext, hasNorms, termDocsEnum, termPositionsEnum, terms, totalTermFreq

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

addReaderClosedListener, close, decRef, document, document, ensureOpen, equals, getRefCount, getTermVector, 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

hasDeletions

public boolean hasDeletions()

Description copied from class: IndexReader

Returns true if any documents have been deleted

Specified by:

hasDeletions in class IndexReader

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

getCoreCacheKey

public Object getCoreCacheKey()

Expert: Returns a key for this IndexReader, so FieldCache/CachingWrapperFilter can find it again. This key must not have equals()/hashCode() methods, so "equals" means "identical".

If the subclass of FilteredIndexReader modifies the contents (but not liveDocs) of the index, you must override this method to provide a different key.

Overrides:

getCoreCacheKey in class IndexReader

getCombinedCoreAndDeletesKey

public Object getCombinedCoreAndDeletesKey()

Expert: Returns a key for this IndexReader that also includes deletions, so FieldCache/CachingWrapperFilter can find it again. This key must not have equals()/hashCode() methods, so "equals" means "identical".

If the subclass of FilteredIndexReader modifies the liveDocs, you must override this method to provide a different key.

Overrides:

getCombinedCoreAndDeletesKey in class IndexReader

toString

public String toString()

Overrides:

toString in class Object

docValues

public DocValues docValues(String field)
                    throws IOException

Description copied from class: AtomicReader

Returns DocValues for this field. This method may return null if the reader has no per-document values stored.

Specified by:

docValues in class AtomicReader

Throws:

IOException

normValues

public DocValues normValues(String field)
                     throws IOException

Description copied from class: AtomicReader

Returns DocValues for this field's normalization values. This method may return null if the field has no norms.

Specified by:

normValues in class AtomicReader

Throws:

IOException