org.apache.lucene.index
Class FilterIndexReader

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

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.

Nested Class Summary

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.FieldOption

Field Summary

protected IndexReader

in

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

deleter

Constructor Summary

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

Method Summary

int	docFreq(Term t) Returns the number of documents containing the term t.
protected void	doClose() Implements close.
protected void	doCommit() Implements commit.
Document	document(int n, FieldSelector fieldSelector) Get the Document at the nth position.
protected void	doDelete(int n) Implements deletion of the document numbered docNum.
protected void	doSetNorm(int d, String f, byte b) Implements setNorm in subclass.
protected void	doUndeleteAll() Implements actual undeleteAll() in subclass.
Collection	getFieldNames(IndexReader.FieldOption fieldNames) Get a list of unique field names that exist in this index and have the specified field option information.
TermFreqVector	getTermFreqVector(int docNumber, String field) Return a term frequency vector for the specified document and field.
TermFreqVector[]	getTermFreqVectors(int docNumber) Return an array of term frequency vectors for the specified document.
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 this IndexReader still works on a current version of the index.
boolean	isDeleted(int n) Returns true if document n has been deleted
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.
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 after a given term.

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

close, commit, deleteDocument, deleteDocuments, directory, document, finalize, getCurrentVersion, getCurrentVersion, getCurrentVersion, getDeleter, indexExists, indexExists, indexExists, isLocked, isLocked, isOptimized, lastModified, lastModified, lastModified, main, open, open, open, setDeleter, setNorm, setNorm, termDocs, termPositions, undeleteAll, unlock

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, 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

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 my either be of type TermFreqVector or of type TermPositionsVector 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 TermPositionsVector 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

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 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.

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:

IOException - If there is a problem reading this document

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

protected void doUndeleteAll()
                      throws IOException

Description copied from class: IndexReader

Implements actual undeleteAll() in subclass.

Specified by:

doUndeleteAll in class IndexReader

Throws:

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.

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

protected void doSetNorm(int d,
                         String f,
                         byte b)
                  throws IOException

Description copied from class: IndexReader

Implements setNorm in subclass.

Specified by:

doSetNorm in class IndexReader

Throws:

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.

Specified by:

terms in class IndexReader

Throws:

IOException

terms

public TermEnum terms(Term t)
               throws IOException

Description copied from class: IndexReader

Returns an enumeration of all terms after a given 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

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

termDocs

public TermDocs termDocs()
                  throws IOException

Description copied from class: IndexReader

Returns an unpositioned TermDocs enumerator.

Specified by:

termDocs in class IndexReader

Throws:

IOException

termPositions

public TermPositions termPositions()
                            throws IOException

Description copied from class: IndexReader

Returns an unpositioned TermPositions enumerator.

Specified by:

termPositions in class IndexReader

Throws:

IOException

doDelete

protected void doDelete(int n)
                 throws IOException

Description copied from class: IndexReader

Implements deletion of the document numbered docNum. Applications should call IndexReader.deleteDocument(int) or IndexReader.deleteDocuments(Term).

Specified by:

doDelete in class IndexReader

Throws:

IOException

doCommit

protected void doCommit()
                 throws IOException

Description copied from class: IndexReader

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

getFieldNames

public Collection getFieldNames(IndexReader.FieldOption fieldNames)

Description copied from class: IndexReader

Get a list of unique field names that exist in this index and have the specified field option information.

Specified by:

getFieldNames in class IndexReader

Parameters:

fieldNames - specifies which field option should be available for the returned fields

Returns:

Collection of Strings indicating the names of the fields.

See Also:

IndexReader.FieldOption

getVersion

public long getVersion()

Description copied from class: IndexReader

Version number when this IndexReader was opened.

Overrides:

getVersion in class IndexReader

isCurrent

public boolean isCurrent()
                  throws IOException

Description copied from class: IndexReader

Check whether this IndexReader still works on a current version of the index. If this is not the case you will need to re-open the IndexReader to make sure you see the latest changes made to the index.

Overrides:

isCurrent in class IndexReader

Throws:

IOException