org.apache.lucene.index
Class SlowCompositeReaderWrapper

java.lang.Object
  extended by org.apache.lucene.index.IndexReader
      extended by org.apache.lucene.index.AtomicReader
          extended by org.apache.lucene.index.SlowCompositeReaderWrapper
All Implemented Interfaces:
Closeable

public final class SlowCompositeReaderWrapper
extends AtomicReader

This class forces a composite reader (eg a MultiReader or DirectoryReader) to emulate an atomic reader. This requires implementing the postings APIs on-the-fly, using the static methods in MultiFields, MultiDocValues, by stepping through the sub-readers to merge fields/terms, appending docs, etc.

NOTE: this class almost always results in a performance hit. If this is important to your use case, you'll get better performance by gathering the sub readers using IndexReader.getContext() to get the atomic leaves and then operate per-AtomicReader, instead of using this class.


Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.lucene.index.IndexReader
IndexReader.ReaderClosedListener
 
Constructor Summary
SlowCompositeReaderWrapper(CompositeReader reader)
          Sole constructor, wrapping the provided CompositeReader.
 
Method Summary
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.
 Fields fields()
          Returns Fields for this reader.
 BinaryDocValues getBinaryDocValues(String field)
          Returns BinaryDocValues for this field, or null if no BinaryDocValues were indexed for this field.
 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.
 NumericDocValues getNormValues(String field)
          Returns NumericDocValues representing norms for this field, or null if no NumericDocValues were indexed.
 NumericDocValues getNumericDocValues(String field)
          Returns NumericDocValues for this field, or null if no NumericDocValues were indexed for this field.
 SortedDocValues getSortedDocValues(String field)
          Returns SortedDocValues for this field, or null if no SortedDocValues were indexed for this field.
 SortedSetDocValues getSortedSetDocValues(String field)
          Returns SortedSetDocValues for this field, or null if no SortedSetDocValues were indexed for this field.
 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.
 int numDocs()
          Returns the number of documents in this index.
 String toString()
           
static AtomicReader wrap(IndexReader reader)
          This method is sugar for getting an AtomicReader from an IndexReader of any kind.
 
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
 

Constructor Detail

SlowCompositeReaderWrapper

public SlowCompositeReaderWrapper(CompositeReader reader)
                           throws IOException
Sole constructor, wrapping the provided CompositeReader.

Throws:
IOException
Method Detail

wrap

public static AtomicReader wrap(IndexReader reader)
                         throws IOException
This method is sugar for getting an AtomicReader from an IndexReader of any kind. If the reader is already atomic, it is returned unchanged, otherwise wrapped by this class.

Throws:
IOException

toString

public String toString()
Overrides:
toString in class Object

fields

public Fields fields()
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

getNumericDocValues

public NumericDocValues getNumericDocValues(String field)
                                     throws IOException
Description copied from class: AtomicReader
Returns NumericDocValues for this field, or null if no NumericDocValues were indexed for this field. The returned instance should only be used by a single thread.

Specified by:
getNumericDocValues in class AtomicReader
Throws:
IOException

getBinaryDocValues

public BinaryDocValues getBinaryDocValues(String field)
                                   throws IOException
Description copied from class: AtomicReader
Returns BinaryDocValues for this field, or null if no BinaryDocValues were indexed for this field. The returned instance should only be used by a single thread.

Specified by:
getBinaryDocValues in class AtomicReader
Throws:
IOException

getSortedDocValues

public SortedDocValues getSortedDocValues(String field)
                                   throws IOException
Description copied from class: AtomicReader
Returns SortedDocValues for this field, or null if no SortedDocValues were indexed for this field. The returned instance should only be used by a single thread.

Specified by:
getSortedDocValues in class AtomicReader
Throws:
IOException

getSortedSetDocValues

public SortedSetDocValues getSortedSetDocValues(String field)
                                         throws IOException
Description copied from class: AtomicReader
Returns SortedSetDocValues for this field, or null if no SortedSetDocValues were indexed for this field. The returned instance should only be used by a single thread.

Specified by:
getSortedSetDocValues in class AtomicReader
Throws:
IOException

getNormValues

public NumericDocValues getNormValues(String field)
                               throws IOException
Description copied from class: AtomicReader
Returns NumericDocValues representing norms for this field, or null if no NumericDocValues were indexed. The returned instance should only be used by a single thread.

Specified by:
getNormValues in class AtomicReader
Throws:
IOException

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

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

hasDeletions

public boolean hasDeletions()
Description copied from class: IndexReader
Returns true if any documents have been deleted

Specified by:
hasDeletions in class IndexReader

getCoreCacheKey

public Object getCoreCacheKey()
Description copied from class: IndexReader
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".

Overrides:
getCoreCacheKey in class IndexReader

getCombinedCoreAndDeletesKey

public Object getCombinedCoreAndDeletesKey()
Description copied from class: IndexReader
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".

Overrides:
getCombinedCoreAndDeletesKey in class IndexReader

doClose

protected void doClose()
                throws IOException
Description copied from class: IndexReader
Implements close.

Specified by:
doClose in class IndexReader
Throws:
IOException


Copyright © 2000-2013 Apache Software Foundation. All Rights Reserved.