org.apache.lucene.index
Class MultiReader

java.lang.Object
  extended by org.apache.lucene.index.IndexReader
      extended by org.apache.lucene.index.MultiReader

public class MultiReader
extends IndexReader

An IndexReader which reads multiple indexes, appending their content.

Version:
$Id: MultiReader.java 355181 2005-12-08 19:53:06Z cutting $

Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.lucene.index.IndexReader
IndexReader.FieldOption
 
Constructor Summary
MultiReader(IndexReader[] subReaders)
          Construct a MultiReader aggregating the named set of (sub)readers.
 
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)
          Returns the stored fields of the nth Document in this index.
protected  void doDelete(int n)
          Implements deletion of the document numbered docNum.
protected  void doSetNorm(int n, String field, byte value)
          Implements setNorm in subclass.
protected  void doUndeleteAll()
          Implements actual undeleteAll() in subclass.
 Collection getFieldNames()
          Returns a list of all unique field names that exist in the index pointed to by this IndexReader.
 Collection getFieldNames(boolean indexed)
          Returns a list of all unique field names that exist in the index pointed to by this IndexReader.
 Collection getFieldNames(IndexReader.FieldOption fieldNames)
          Get a list of unique field names that exist in this index and have the specified field option information.
 Collection getIndexedFieldNames(Field.TermVector tvSpec)
          Get a list of unique field names that exist in this index, are indexed, and have the specified term vector information.
 TermFreqVector getTermFreqVector(int n, String field)
          Return a term frequency vector for the specified document and field.
 TermFreqVector[] getTermFreqVectors(int n)
          Return an array of term frequency vectors for the specified document.
 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 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 field)
          Returns the byte-encoded normalization factor for the named field of every document.
 void norms(String field, byte[] result, 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 term)
          Returns an enumeration of all terms after a given term.
 
Methods inherited from class org.apache.lucene.index.IndexReader
close, commit, delete, delete, deleteDocument, deleteDocuments, directory, finalize, getCurrentVersion, getCurrentVersion, getCurrentVersion, getIndexedFieldNames, getVersion, indexExists, indexExists, indexExists, isCurrent, isLocked, isLocked, lastModified, lastModified, lastModified, main, open, open, open, setNorm, setNorm, termDocs, termPositions, undeleteAll, unlock
 
Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

MultiReader

public MultiReader(IndexReader[] subReaders)
            throws IOException

Construct a MultiReader aggregating the named set of (sub)readers. Directory locking for delete, undeleteAll, and setNorm operations is left to the subreaders.

Note that all subreaders are closed if this Multireader is closed.

Parameters:
subReaders - set of (sub)readers
Throws:
IOException
Method Detail

getTermFreqVectors

public TermFreqVector[] getTermFreqVectors(int n)
                                    throws IOException
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 vector contains term numbers and frequencies for all terms in a given vectorized field. If no such fields existed, the method returns null.

Specified by:
getTermFreqVectors in class IndexReader
Parameters:
n - 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 n,
                                        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:
n - 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)
                  throws IOException
Description copied from class: IndexReader
Returns the stored fields of the nth Document in this index.

Specified by:
document in class IndexReader
Throws:
IOException

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

doDelete

protected void doDelete(int n)
                 throws IOException
Description copied from class: IndexReader
Implements deletion of the document numbered docNum. Applications should call IndexReader.delete(int) or IndexReader.delete(Term).

Specified by:
doDelete in class IndexReader
Throws:
IOException

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 field)
             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:
Field.setBoost(float)

norms

public void norms(String field,
                  byte[] result,
                  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:
Field.setBoost(float)

doSetNorm

protected void doSetNorm(int n,
                         String field,
                         byte value)
                  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 term)
               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

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()
                         throws IOException
Description copied from class: IndexReader
Returns a list of all unique field names that exist in the index pointed to by this IndexReader.

Specified by:
getFieldNames in class IndexReader
Returns:
Collection of Strings indicating the names of the fields
Throws:
IOException - if there is a problem with accessing the index
See Also:
IndexReader.getFieldNames()

getFieldNames

public Collection getFieldNames(boolean indexed)
                         throws IOException
Description copied from class: IndexReader
Returns a list of all unique field names that exist in the index pointed to by this IndexReader. The boolean argument specifies whether the fields returned are indexed or not.

Specified by:
getFieldNames in class IndexReader
Parameters:
indexed - true if only indexed fields should be returned; false if only unindexed fields should be returned.
Returns:
Collection of Strings indicating the names of the fields
Throws:
IOException - if there is a problem with accessing the index
See Also:
IndexReader.getFieldNames(boolean)

getIndexedFieldNames

public Collection getIndexedFieldNames(Field.TermVector tvSpec)
Description copied from class: IndexReader
Get a list of unique field names that exist in this index, are indexed, and have the specified term vector information.

Specified by:
getIndexedFieldNames in class IndexReader
Parameters:
tvSpec - specifies which term vector information should be available for the fields
Returns:
Collection of Strings indicating the names of the fields

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.getFieldNames(IndexReader.FieldOption)


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