org.apache.lucene.index
Class FilterIndexReader

java.lang.Object
  extended by org.apache.lucene.index.IndexReader
      extended by 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
hasChanges
 
Constructor Summary
FilterIndexReader(IndexReader in)
          Construct a FilterIndexReader based on the specified base reader.
 
Method Summary
 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()
          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.
 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.
 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 is still using the current (i.e., most recently committed) version of the index.
 boolean isDeleted(int n)
          Returns true if document n has been deleted
 boolean isOptimized()
          Checks is the index is optimized (if it has a single segment and no deletions).
 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 starting at a given term.
 
Methods inherited from class org.apache.lucene.index.IndexReader
acquireWriteLock, close, commit, decRef, deleteDocument, deleteDocuments, document, ensureOpen, flush, getCurrentVersion, getCurrentVersion, getCurrentVersion, getTermInfosIndexDivisor, incRef, indexExists, indexExists, indexExists, isLocked, isLocked, lastModified, lastModified, lastModified, main, open, open, open, open, reopen, setNorm, setNorm, setTermInfosIndexDivisor, termDocs, termPositions, undeleteAll, unlock
 
Methods inherited from class java.lang.Object
clone, equals, finalize, 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

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

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

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.

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 nth 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 nth 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

protected void doUndeleteAll()
                      throws CorruptIndexException,
                             IOException
Description copied from class: IndexReader
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.

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 CorruptIndexException,
                         IOException
Description copied from class: IndexReader
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 therm. 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.

Specified by:
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

protected void doDelete(int n)
                 throws CorruptIndexException,
                        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:
CorruptIndexException
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. Not implemented in the IndexReader base class.

Overrides:
getVersion in class IndexReader

isCurrent

public boolean isCurrent()
                  throws CorruptIndexException,
                         IOException
Description copied from class: IndexReader
Check whether this IndexReader is still using the current (i.e., most recently committed) version of the index. If a writer has committed any changes to the index since this reader was opened, this will return false, in which case you must open a new IndexReader in order to see the changes. See the description of the autoCommit flag which controls when the IndexWriter actually commits changes to the index.

Not implemented in the IndexReader base class.

Overrides:
isCurrent in class IndexReader
Throws:
CorruptIndexException - if the index is corrupt
IOException - if there is a low-level IO error

isOptimized

public boolean isOptimized()
Description copied from class: IndexReader
Checks is the index is optimized (if it has a single segment and no deletions). Not implemented in the IndexReader base class.

Overrides:
isOptimized in class IndexReader
Returns:
true if the index is optimized; false otherwise


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