org.apache.lucene.index
Class PruningReader

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

All Implemented Interfaces:

Closeable, Cloneable

public class PruningReader
extends FilterIndexReader

This class produces a subset of the input index, by removing some postings data according to rules implemented in a TermPruningPolicy, and optionally it can also remove stored fields of documents according to rules implemented in a StorePruningPolicy.

Nested Class Summary

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

FilterIndexReader.FilterTermDocs, FilterIndexReader.FilterTermEnum, FilterIndexReader.FilterTermPositions

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

IndexReader.ReaderClosedListener

Field Summary

protected int	delTermCount
protected int	delVecCount
protected int	docCount
protected int	prunedVecCount
protected StorePruningPolicy	storePolicy
protected int	termCount
protected TermPruningPolicy	termPolicy
protected int	vecCount

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

in

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

hasChanges

Constructor Summary

PruningReader(IndexReader in, StorePruningPolicy storePolicy, TermPruningPolicy termPolicy)
Constructor.

Method Summary

Document	document(int n, FieldSelector fieldSelector) Applies a StorePruningPolicy to stored fields of a document.
FieldInfos	getFieldInfos() Applies a StorePruningPolicy to the list of available field infos.
IndexReader[]	getSequentialSubReaders() Expert: returns the sequential sub readers that this reader is logically composed of.
TermFreqVector[]	getTermFreqVectors(int docNumber) Applies TermPruningPolicy to terms inside term vectors.
TermPositions	termPositions() Applies TermPruningPolicy to term positions.
TermEnum	terms() Applies TermPruningPolicy to term enum.

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

directory, docFreq, doClose, doCommit, doDelete, doSetNorm, doUndeleteAll, getCommitUserData, getCoreCacheKey, getDeletesCacheKey, getIndexCommit, getTermFreqVector, getTermFreqVector, getTermFreqVector, getTermInfosIndexDivisor, getUniqueTermCount, getVersion, hasDeletions, hasNorms, isCurrent, isDeleted, isOptimized, maxDoc, norms, norms, numDocs, termDocs, termDocs, terms, 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

docCount

protected int docCount

vecCount

protected int vecCount

termCount

protected int termCount

delTermCount

protected int delTermCount

prunedVecCount

protected int prunedVecCount

delVecCount

protected int delVecCount

termPolicy

protected TermPruningPolicy termPolicy

storePolicy

protected StorePruningPolicy storePolicy

Constructor Detail

PruningReader

public PruningReader(IndexReader in,
                     StorePruningPolicy storePolicy,
                     TermPruningPolicy termPolicy)

Constructor.

Parameters:

in - input reader

storePolicy - implementation of StorePruningPolicy - if null then stored values will be retained as is.

termPolicy - implementation of TermPruningPolicy, must not be null.

Method Detail

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 FilterIndexReader

document

public Document document(int n,
                         FieldSelector fieldSelector)
                  throws CorruptIndexException,
                         IOException

Applies a StorePruningPolicy to stored fields of a document.

Overrides:

document in class FilterIndexReader

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

getFieldInfos

public FieldInfos getFieldInfos()

Applies a StorePruningPolicy to the list of available field infos.

Overrides:

getFieldInfos in class FilterIndexReader

getTermFreqVectors

public TermFreqVector[] getTermFreqVectors(int docNumber)
                                    throws IOException

Applies TermPruningPolicy to terms inside term vectors.

Overrides:

getTermFreqVectors in class FilterIndexReader

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

termPositions

public TermPositions termPositions()
                            throws IOException

Applies TermPruningPolicy to term positions.

Overrides:

termPositions in class FilterIndexReader

Throws:

IOException - if there is a low-level IO error

terms

public TermEnum terms()
               throws IOException

Applies TermPruningPolicy to term enum.

Overrides:

terms in class FilterIndexReader

Throws:

IOException - if there is a low-level IO error