Class BaseCompositeReader<R extends IndexReader>
- java.lang.Object
-
- org.apache.lucene.index.IndexReader
-
- org.apache.lucene.index.CompositeReader
-
- org.apache.lucene.index.BaseCompositeReader<R>
-
- All Implemented Interfaces:
Closeable,AutoCloseable
- Direct Known Subclasses:
DirectoryReader,MultiReader,ParallelCompositeReader
public abstract class BaseCompositeReader<R extends IndexReader> extends CompositeReader
Base class for implementingCompositeReaders based on an array of sub-readers. The implementing class has to add code for correctly refcounting and closing the sub-readers.User code will most likely use
MultiReaderto build a composite reader on a set of sub-readers (like severalDirectoryReaders).For efficiency, in this API documents are often referred to via document numbers, non-negative integers which each name a unique document in the index. These document numbers are ephemeral -- they may change as documents are added to and deleted from an index. Clients should thus not rely on a given document having the same number between sessions.
NOTE:
IndexReaderinstances are completely thread safe, meaning multiple threads can call any of its methods, concurrently. If your application requires external synchronization, you should not synchronize on theIndexReaderinstance; use your own (non-Lucene) objects instead.- See Also:
MultiReader- NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.
-
-
Nested Class Summary
-
Nested classes/interfaces inherited from class org.apache.lucene.index.IndexReader
IndexReader.CacheHelper, IndexReader.CacheKey, IndexReader.ClosedListener
-
-
Field Summary
Fields Modifier and Type Field Description protected Comparator<R>subReadersSorterA comparator for sorting sub-readers
-
Constructor Summary
Constructors Modifier Constructor Description protectedBaseCompositeReader(R[] subReaders, Comparator<R> subReadersSorter)Constructs aBaseCompositeReaderon the given subReaders.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description intdocFreq(Term term)Returns the number of documents containing theterm.voiddocument(int docID, StoredFieldVisitor visitor)Expert: visits the fields of a stored document, for custom processing/loading of each field.intgetDocCount(String field)Returns the number of documents that have at least one term for this field.protected List<? extends R>getSequentialSubReaders()Expert: returns the sequential sub readers that this reader is logically composed of.longgetSumDocFreq(String field)Returns the sum ofTermsEnum.docFreq()for all terms in this field.longgetSumTotalTermFreq(String field)Returns the sum ofTermsEnum.totalTermFreq()for all terms in this field.FieldsgetTermVectors(int docID)Retrieve term vectors for this document, or null if term vectors were not indexed.intmaxDoc()Returns one greater than the largest possible document number.intnumDocs()Returns the number of documents in this index.protected intreaderBase(int readerIndex)Helper method for subclasses to get the docBase of the given sub-reader index.protected intreaderIndex(int docID)Helper method for subclasses to get the corresponding reader for a doc IDStoredFieldsstoredFields()Returns aStoredFieldsreader for the stored fields of this index.TermVectorstermVectors()Returns aTermVectorsreader for the term vectors of this index.longtotalTermFreq(Term term)Returns the total number of occurrences oftermacross all documents (the sum of the freq() for each doc that has this term).-
Methods inherited from class org.apache.lucene.index.CompositeReader
getContext, toString
-
Methods inherited from class org.apache.lucene.index.IndexReader
close, decRef, doClose, document, document, ensureOpen, equals, getReaderCacheHelper, getRefCount, getTermVector, hasDeletions, hashCode, incRef, leaves, notifyReaderClosedListeners, numDeletedDocs, registerParentReader, tryIncRef
-
-
-
-
Field Detail
-
subReadersSorter
protected final Comparator<R extends IndexReader> subReadersSorter
A comparator for sorting sub-readers
-
-
Constructor Detail
-
BaseCompositeReader
protected BaseCompositeReader(R[] subReaders, Comparator<R> subReadersSorter) throws IOException
Constructs aBaseCompositeReaderon the given subReaders.- Parameters:
subReaders- the wrapped sub-readers. This array is returned bygetSequentialSubReaders()and used to resolve the correct subreader for docID-based methods. Please note: This array is not cloned and not protected for modification, the subclass is responsible to do this.subReadersSorter- – a comparator for sorting sub readers. If notnull, this comparator is used to sort sub readers, before using the for resolving doc IDs.- Throws:
IOException
-
-
Method Detail
-
getTermVectors
public final Fields getTermVectors(int docID) throws IOException
Description copied from class:IndexReaderRetrieve 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:
getTermVectorsin classIndexReader- Throws:
IOException
-
termVectors
public final TermVectors termVectors() throws IOException
Description copied from class:IndexReaderReturns aTermVectorsreader for the term vectors of this index.This call never returns
null, even if no term vectors were indexed. The returned instance should only be used by a single thread.Example:
TopDocs hits = searcher.search(query, 10); TermVectors termVectors = reader.termVectors(); for (ScoreDoc hit : hits.scoreDocs) { Fields vector = termVectors.get(hit.doc); }- Specified by:
termVectorsin classIndexReader- Throws:
IOException- If there is a low-level IO error
-
numDocs
public final int numDocs()
Description copied from class:IndexReaderReturns the number of documents in this index.NOTE: This operation may run in O(maxDoc). Implementations that can't return this number in constant-time should cache it.
- Specified by:
numDocsin classIndexReader
-
maxDoc
public final int maxDoc()
Description copied from class:IndexReaderReturns 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:
maxDocin classIndexReader
-
document
public final void document(int docID, StoredFieldVisitor visitor) throws IOExceptionDescription copied from class:IndexReaderExpert: visits the fields of a stored document, for custom processing/loading of each field. If you simply want to load all fields, useIndexReader.document(int). If you want to load a subset, useDocumentStoredFieldVisitor.- Specified by:
documentin classIndexReader- Throws:
IOException
-
storedFields
public final StoredFields storedFields() throws IOException
Description copied from class:IndexReaderReturns aStoredFieldsreader for the stored fields of this index.This call never returns
null, even if no stored fields were indexed. The returned instance should only be used by a single thread.Example:
TopDocs hits = searcher.search(query, 10); StoredFields storedFields = reader.storedFields(); for (ScoreDoc hit : hits.scoreDocs) { Document doc = storedFields.document(hit.doc); }- Specified by:
storedFieldsin classIndexReader- Throws:
IOException- If there is a low-level IO error
-
docFreq
public final int docFreq(Term term) throws IOException
Description copied from class:IndexReaderReturns the number of documents containing theterm. This method returns 0 if the term or field does not exists. This method does not take into account deleted documents that have not yet been merged away.- Specified by:
docFreqin classIndexReader- Throws:
IOException- See Also:
TermsEnum.docFreq()
-
totalTermFreq
public final long totalTermFreq(Term term) throws IOException
Description copied from class:IndexReaderReturns the total number of occurrences oftermacross all documents (the sum of the freq() for each doc that has this term). Note that, like other term measures, this measure does not take deleted documents into account.- Specified by:
totalTermFreqin classIndexReader- Throws:
IOException
-
getSumDocFreq
public final long getSumDocFreq(String field) throws IOException
Description copied from class:IndexReaderReturns the sum ofTermsEnum.docFreq()for all terms in this field. Note that, just like other term measures, this measure does not take deleted documents into account.- Specified by:
getSumDocFreqin classIndexReader- Throws:
IOException- See Also:
Terms.getSumDocFreq()
-
getDocCount
public final int getDocCount(String field) throws IOException
Description copied from class:IndexReaderReturns the number of documents that have at least one term for this field. Note that, just like other term measures, this measure does not take deleted documents into account.- Specified by:
getDocCountin classIndexReader- Throws:
IOException- See Also:
Terms.getDocCount()
-
getSumTotalTermFreq
public final long getSumTotalTermFreq(String field) throws IOException
Description copied from class:IndexReaderReturns the sum ofTermsEnum.totalTermFreq()for all terms in this field. Note that, just like other term measures, this measure does not take deleted documents into account.- Specified by:
getSumTotalTermFreqin classIndexReader- Throws:
IOException- See Also:
Terms.getSumTotalTermFreq()
-
readerIndex
protected final int readerIndex(int docID)
Helper method for subclasses to get the corresponding reader for a doc ID
-
readerBase
protected final int readerBase(int readerIndex)
Helper method for subclasses to get the docBase of the given sub-reader index.
-
getSequentialSubReaders
protected final List<? extends R> getSequentialSubReaders()
Description copied from class:CompositeReaderExpert: returns the sequential sub readers that this reader is logically composed of. This method may not returnnull.NOTE: In contrast to previous Lucene versions this method is no longer public, code that wants to get all
LeafReaders this composite is composed of should useIndexReader.leaves().- Specified by:
getSequentialSubReadersin classCompositeReader- See Also:
IndexReader.leaves()
-
-