org.apache.lucene.index

Class IndexReader

java.lang.Object

org.apache.lucene.index.IndexReader

Direct Known Subclasses:

FilterIndexReader, MultiReader, ParallelReader

public abstract class IndexReader
extends java.lang.Object

IndexReader is an abstract class, providing an interface for accessing an index. Search of an index is done entirely through this abstract interface, so that any subclass which implements it is searchable.

Concrete subclasses of IndexReader are usually constructed with a call to one of the static open() methods, e.g. open(String).

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.

An IndexReader can be opened on a directory for which an IndexWriter is opened already, but it cannot be used to delete documents from the index then.

NOTE: for backwards API compatibility, several methods are not listed as abstract, but have no useful implementations in this base class and instead always throw UnsupportedOperationException. Subclasses are strongly encouraged to override these methods, but in many cases may not need to.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	IndexReader.FieldOption Constants describing field properties, for example used for getFieldNames(FieldOption).

Method Summary

Modifier and Type	Method and Description
void	close() Closes files associated with this index.
void	deleteDocument(int docNum) Deletes the document numbered docNum.
int	deleteDocuments(Term term) Deletes all documents that have a given term indexed.
Directory	directory() Returns the directory associated with this index.
abstract int	docFreq(Term t) Returns the number of documents containing the term t.
Document	document(int n) Returns the stored fields of the nth Document in this index.
abstract Document	document(int n, FieldSelector fieldSelector) Get the Document at the nth position.
void	flush()
static long	getCurrentVersion(Directory directory) Reads version number from segments files.
static long	getCurrentVersion(java.io.File directory) Reads version number from segments files.
static long	getCurrentVersion(java.lang.String directory) Reads version number from segments files.
abstract java.util.Collection	getFieldNames(IndexReader.FieldOption fldOption) Get a list of unique field names that exist in this index and have the specified field option information.
abstract TermFreqVector	getTermFreqVector(int docNumber, java.lang.String field) Return a term frequency vector for the specified document and field.
abstract void	getTermFreqVector(int docNumber, java.lang.String field, TermVectorMapper mapper) Load the Term Vector into a user-defined data structure instead of relying on the parallel arrays of the TermFreqVector.
abstract void	getTermFreqVector(int docNumber, TermVectorMapper mapper) Map all the term vectors for all fields in a Document
abstract TermFreqVector[]	getTermFreqVectors(int docNumber) Return an array of term frequency vectors for the specified document.
int	getTermInfosIndexDivisor() For IndexReader implementations that use TermInfosReader to read terms, this returns the current indexDivisor.
long	getVersion() Version number when this IndexReader was opened.
abstract boolean	hasDeletions() Returns true if any documents have been deleted
boolean	hasNorms(java.lang.String field) Returns true if there are norms stored for this field.
static boolean	indexExists(Directory directory) Returns true if an index exists at the specified directory.
static boolean	indexExists(java.io.File directory) Returns true if an index exists at the specified directory.
static boolean	indexExists(java.lang.String directory) Returns true if an index exists at the specified directory.
boolean	isCurrent() Check whether this IndexReader is still using the current (i.e., most recently committed) version of the index.
abstract boolean	isDeleted(int n) Returns true if document n has been deleted
static boolean	isLocked(Directory directory) Returns true iff the index in the named directory is currently locked.
static boolean	isLocked(java.lang.String directory) Returns true iff the index in the named directory is currently locked.
boolean	isOptimized() Checks is the index is optimized (if it has a single segment and no deletions).
static long	lastModified(Directory directory2) Returns the time the index in the named directory was last modified.
static long	lastModified(java.io.File fileDirectory) Returns the time the index in the named directory was last modified.
static long	lastModified(java.lang.String directory) Returns the time the index in the named directory was last modified.
static void	main(java.lang.String[] args) Prints the filename and size of each file within a given compound file.
abstract int	maxDoc() Returns one greater than the largest possible document number.
abstract byte[]	norms(java.lang.String field) Returns the byte-encoded normalization factor for the named field of every document.
abstract void	norms(java.lang.String field, byte[] bytes, int offset) Reads the byte-encoded normalization factor for the named field of every document.
abstract int	numDocs() Returns the number of documents in this index.
static IndexReader	open(Directory directory) Returns an IndexReader reading the index in the given Directory.
static IndexReader	open(Directory directory, IndexDeletionPolicy deletionPolicy) Expert: returns an IndexReader reading the index in the given Directory, with a custom IndexDeletionPolicy.
static IndexReader	open(java.io.File path) Returns an IndexReader reading the index in an FSDirectory in the named path.
static IndexReader	open(java.lang.String path) Returns an IndexReader reading the index in an FSDirectory in the named path.
IndexReader	reopen() Refreshes an IndexReader if the index has changed since this instance was (re)opened.
void	setNorm(int doc, java.lang.String field, byte value) Expert: Resets the normalization factor for the named field of the named document.
void	setNorm(int doc, java.lang.String field, float value) Expert: Resets the normalization factor for the named field of the named document.
void	setTermInfosIndexDivisor(int indexDivisor) For IndexReader implementations that use TermInfosReader to read terms, this sets the indexDivisor to subsample the number of indexed terms loaded into memory.
abstract TermDocs	termDocs() Returns an unpositioned TermDocs enumerator.
TermDocs	termDocs(Term term) Returns an enumeration of all the documents which contain term.
abstract TermPositions	termPositions() Returns an unpositioned TermPositions enumerator.
TermPositions	termPositions(Term term) Returns an enumeration of all the documents which contain term.
abstract TermEnum	terms() Returns an enumeration of all the terms in the index.
abstract TermEnum	terms(Term t) Returns an enumeration of all terms starting at a given term.
void	undeleteAll() Undeletes all documents currently marked as deleted in this index.
static void	unlock(Directory directory) Forcibly unlocks the index in the named directory.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

open

public static IndexReader open(java.lang.String path)
                        throws CorruptIndexException,
                               java.io.IOException

Returns an IndexReader reading the index in an FSDirectory in the named path.

Parameters:

path - the path to the index directory

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

open

public static IndexReader open(java.io.File path)
                        throws CorruptIndexException,
                               java.io.IOException

Returns an IndexReader reading the index in an FSDirectory in the named path.

Parameters:

path - the path to the index directory

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

open

public static IndexReader open(Directory directory)
                        throws CorruptIndexException,
                               java.io.IOException

Returns an IndexReader reading the index in the given Directory.

Parameters:

directory - the index directory

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

open

public static IndexReader open(Directory directory,
                               IndexDeletionPolicy deletionPolicy)
                        throws CorruptIndexException,
                               java.io.IOException

Expert: returns an IndexReader reading the index in the given Directory, with a custom IndexDeletionPolicy.

Parameters:

directory - the index directory

deletionPolicy - a custom deletion policy (only used if you use this reader to perform deletes or to set norms); see IndexWriter for details.

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

reopen

public IndexReader reopen()
                   throws CorruptIndexException,
                          java.io.IOException

Refreshes an IndexReader if the index has changed since this instance was (re)opened.

Opening an IndexReader is an expensive operation. This method can be used to refresh an existing IndexReader to reduce these costs. This method tries to only load segments that have changed or were created after the IndexReader was (re)opened.

If the index has not changed since this instance was (re)opened, then this call is a NOOP and returns this instance. Otherwise, a new instance is returned. The old instance is not closed and remains usable.
Note: The re-opened reader instance and the old instance might share the same resources. For this reason no index modification operations (e. g. deleteDocument(int), setNorm(int, String, byte)) should be performed using one of the readers until the old reader instance is closed. Otherwise, the behavior of the readers is undefined.

You can determine whether a reader was actually reopened by comparing the old instance with the instance returned by this method:

 IndexReader reader = ... 
 ...
 IndexReader new = r.reopen();
 if (new != reader) {
   ...     // reader was reopened
   reader.close(); 
 }
 reader = new;
 ...
 

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

directory

public Directory directory()

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.

Throws:

java.lang.UnsupportedOperationException - if no directory

lastModified

public static long lastModified(java.lang.String directory)
                         throws CorruptIndexException,
                                java.io.IOException

Returns the time the index in the named directory was last modified. Do not use this to check whether the reader is still up-to-date, use isCurrent() instead.

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

lastModified

public static long lastModified(java.io.File fileDirectory)
                         throws CorruptIndexException,
                                java.io.IOException

Returns the time the index in the named directory was last modified. Do not use this to check whether the reader is still up-to-date, use isCurrent() instead.

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

lastModified

public static long lastModified(Directory directory2)
                         throws CorruptIndexException,
                                java.io.IOException

Returns the time the index in the named directory was last modified. Do not use this to check whether the reader is still up-to-date, use isCurrent() instead.

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

getCurrentVersion

public static long getCurrentVersion(java.lang.String directory)
                              throws CorruptIndexException,
                                     java.io.IOException

Reads version number from segments files. The version number is initialized with a timestamp and then increased by one for each change of the index.

Parameters:

directory - where the index resides.

Returns:

version number.

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

getCurrentVersion

public static long getCurrentVersion(java.io.File directory)
                              throws CorruptIndexException,
                                     java.io.IOException

Reads version number from segments files. The version number is initialized with a timestamp and then increased by one for each change of the index.

Parameters:

directory - where the index resides.

Returns:

version number.

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

getCurrentVersion

public static long getCurrentVersion(Directory directory)
                              throws CorruptIndexException,
                                     java.io.IOException

Reads version number from segments files. The version number is initialized with a timestamp and then increased by one for each change of the index.

Parameters:

directory - where the index resides.

Returns:

version number.

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

getVersion

public long getVersion()

Version number when this IndexReader was opened. Not implemented in the IndexReader base class.

Throws:

java.lang.UnsupportedOperationException - unless overridden in subclass

setTermInfosIndexDivisor

public void setTermInfosIndexDivisor(int indexDivisor)
                              throws java.lang.IllegalStateException

For IndexReader implementations that use TermInfosReader to read terms, this sets the indexDivisor to subsample the number of indexed terms loaded into memory. This has the same effect as IndexWriter.setTermIndexInterval(int) except that setting must be done at indexing time while this setting can be set per reader. When set to N, then one in every N*termIndexInterval terms in the index is loaded into memory. By setting this to a value > 1 you can reduce memory usage, at the expense of higher latency when loading a TermInfo. The default value is 1.

NOTE: you must call this before the term index is loaded. If the index is already loaded, an IllegalStateException is thrown.

Throws:

java.lang.IllegalStateException - if the term index has already been loaded into memory

getTermInfosIndexDivisor

public int getTermInfosIndexDivisor()

For IndexReader implementations that use TermInfosReader to read terms, this returns the current indexDivisor.

See Also:

setTermInfosIndexDivisor(int)

isCurrent

public boolean isCurrent()
                  throws CorruptIndexException,
                         java.io.IOException

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.

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

java.lang.UnsupportedOperationException - unless overridden in subclass

isOptimized

public boolean isOptimized()

Checks is the index is optimized (if it has a single segment and no deletions). Not implemented in the IndexReader base class.

Returns:

true if the index is optimized; false otherwise

Throws:

java.lang.UnsupportedOperationException - unless overridden in subclass

getTermFreqVectors

public abstract TermFreqVector[] getTermFreqVectors(int docNumber)
                                             throws java.io.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 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.

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:

java.io.IOException - if index cannot be accessed

See Also:

Field.TermVector

getTermFreqVector

public abstract TermFreqVector getTermFreqVector(int docNumber,
                                                 java.lang.String field)
                                          throws java.io.IOException

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.

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:

java.io.IOException - if index cannot be accessed

See Also:

Field.TermVector

getTermFreqVector

public abstract void getTermFreqVector(int docNumber,
                                       java.lang.String field,
                                       TermVectorMapper mapper)
                                throws java.io.IOException

Load the Term Vector into a user-defined data structure instead of relying on the parallel arrays of the TermFreqVector.

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:

java.io.IOException - if term vectors cannot be accessed or if they do not exist on the field and doc. specified.

getTermFreqVector

public abstract void getTermFreqVector(int docNumber,
                                       TermVectorMapper mapper)
                                throws java.io.IOException

Map all the term vectors for all fields in a Document

Parameters:

docNumber - The number of the document to load the vector for

mapper - The TermVectorMapper to process the vector. Must not be null

Throws:

java.io.IOException - if term vectors cannot be accessed or if they do not exist on the field and doc. specified.

indexExists

public static boolean indexExists(java.lang.String directory)

Returns true if an index exists at the specified directory. If the directory does not exist or if there is no index in it. false is returned.

Parameters:

directory - the directory to check for an index

Returns:

true if an index exists; false otherwise

indexExists

public static boolean indexExists(java.io.File directory)

Returns true if an index exists at the specified directory. If the directory does not exist or if there is no index in it.

Parameters:

directory - the directory to check for an index

Returns:

true if an index exists; false otherwise

indexExists

public static boolean indexExists(Directory directory)
                           throws java.io.IOException

Returns true if an index exists at the specified directory. If the directory does not exist or if there is no index in it.

Parameters:

directory - the directory to check for an index

Returns:

true if an index exists; false otherwise

Throws:

java.io.IOException - if there is a problem with accessing the index

numDocs

public abstract int numDocs()

Returns the number of documents in this index.

maxDoc

public abstract int maxDoc()

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.

document

public Document document(int n)
                  throws CorruptIndexException,
                         java.io.IOException

Returns the stored fields of the n^th Document in this index.

Throws:

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

document

public abstract Document document(int n,
                                  FieldSelector fieldSelector)
                           throws CorruptIndexException,
                                  java.io.IOException

Get the Document at the n^th 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.

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

java.io.IOException - if there is a low-level IO error

See Also:

Fieldable, FieldSelector, SetBasedFieldSelector, LoadFirstFieldSelector

isDeleted

public abstract boolean isDeleted(int n)

Returns true if document n has been deleted

hasDeletions

public abstract boolean hasDeletions()

Returns true if any documents have been deleted

hasNorms

public boolean hasNorms(java.lang.String field)
                 throws java.io.IOException

Returns true if there are norms stored for this field.

Throws:

java.io.IOException

norms

public abstract byte[] norms(java.lang.String field)
                      throws java.io.IOException

Returns the byte-encoded normalization factor for the named field of every document. This is used by the search code to score documents.

Throws:

java.io.IOException

See Also:

AbstractField.setBoost(float)

norms

public abstract void norms(java.lang.String field,
                           byte[] bytes,
                           int offset)
                    throws java.io.IOException

Reads the byte-encoded normalization factor for the named field of every document. This is used by the search code to score documents.

Throws:

java.io.IOException

See Also:

AbstractField.setBoost(float)

setNorm

public final void setNorm(int doc,
                          java.lang.String field,
                          byte value)
                   throws StaleReaderException,
                          CorruptIndexException,
                          LockObtainFailedException,
                          java.io.IOException

Expert: Resets the normalization factor for the named field of the named document. The norm represents the product of the field's boost and its length normalization. Thus, to preserve the length normalization values when resetting this, one should base the new value upon the old.

Throws:

StaleReaderException - if the index has changed since this reader was opened

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

java.io.IOException - if there is a low-level IO error

See Also:

norms(String), Similarity.decodeNorm(byte)

setNorm

public void setNorm(int doc,
                    java.lang.String field,
                    float value)
             throws StaleReaderException,
                    CorruptIndexException,
                    LockObtainFailedException,
                    java.io.IOException

Expert: Resets the normalization factor for the named field of the named document.

Throws:

StaleReaderException - if the index has changed since this reader was opened

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

java.io.IOException - if there is a low-level IO error

See Also:

norms(String), Similarity.decodeNorm(byte)

terms

public abstract TermEnum terms()
                        throws java.io.IOException

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().

Throws:

java.io.IOException - if there is a low-level IO error

terms

public abstract TermEnum terms(Term t)
                        throws java.io.IOException

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.

Throws:

java.io.IOException - if there is a low-level IO error

docFreq

public abstract int docFreq(Term t)
                     throws java.io.IOException

Returns the number of documents containing the term t.

Throws:

java.io.IOException - if there is a low-level IO error

termDocs

public TermDocs termDocs(Term term)
                  throws java.io.IOException

Returns an enumeration of all the documents which contain term. For each document, the document number, the frequency of the term in that document is also provided, for use in search scoring. Thus, this method implements the mapping:

Term => <docNum, freq>^*

The enumeration is ordered by document number. Each document number is greater than all that precede it in the enumeration.

Throws:

java.io.IOException - if there is a low-level IO error

termDocs

public abstract TermDocs termDocs()
                           throws java.io.IOException

Returns an unpositioned TermDocs enumerator.

Throws:

java.io.IOException - if there is a low-level IO error

termPositions

public TermPositions termPositions(Term term)
                            throws java.io.IOException

Returns an enumeration of all the documents which contain term. For each document, in addition to the document number and frequency of the term in that document, a list of all of the ordinal positions of the term in the document is available. Thus, this method implements the mapping:

Term => <docNum, freq, <pos₁, pos₂, ... pos_freq-1> >^*

This positional information facilitates phrase and proximity searching.

The enumeration is ordered by document number. Each document number is greater than all that precede it in the enumeration.

Throws:

java.io.IOException - if there is a low-level IO error

termPositions

public abstract TermPositions termPositions()
                                     throws java.io.IOException

Returns an unpositioned TermPositions enumerator.

Throws:

java.io.IOException - if there is a low-level IO error

deleteDocument

public final void deleteDocument(int docNum)
                          throws StaleReaderException,
                                 CorruptIndexException,
                                 LockObtainFailedException,
                                 java.io.IOException

Deletes the document numbered docNum. Once a document is deleted it will not appear in TermDocs or TermPostitions enumerations. Attempts to read its field with the document(int) method will result in an error. The presence of this document may still be reflected in the docFreq(org.apache.lucene.index.Term) statistic, though this will be corrected eventually as the index is further modified.

Throws:

StaleReaderException - if the index has changed since this reader was opened

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

java.io.IOException - if there is a low-level IO error

deleteDocuments

public final int deleteDocuments(Term term)
                          throws StaleReaderException,
                                 CorruptIndexException,
                                 LockObtainFailedException,
                                 java.io.IOException

Deletes all documents that have a given term indexed. This is useful if one uses a document field to hold a unique ID string for the document. Then to delete such a document, one merely constructs a term with the appropriate field and the unique ID string as its text and passes it to this method. See deleteDocument(int) for information about when this deletion will become effective.

Returns:

the number of documents deleted

Throws:

StaleReaderException - if the index has changed since this reader was opened

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

java.io.IOException - if there is a low-level IO error

undeleteAll

public final void undeleteAll()
                       throws StaleReaderException,
                              CorruptIndexException,
                              LockObtainFailedException,
                              java.io.IOException

Undeletes all documents currently marked as deleted in this index.

Throws:

StaleReaderException - if the index has changed since this reader was opened

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

CorruptIndexException - if the index is corrupt

java.io.IOException - if there is a low-level IO error

flush

public final void flush()
                 throws java.io.IOException

Throws:

java.io.IOException

close

public final void close()
                 throws java.io.IOException

Closes files associated with this index. Also saves any new deletions to disk. No other methods should be called after this has been called.

Throws:

java.io.IOException - if there is a low-level IO error

getFieldNames

public abstract java.util.Collection getFieldNames(IndexReader.FieldOption fldOption)

Get a list of unique field names that exist in this index and have the specified field option information.

Parameters:

fldOption - 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

isLocked

public static boolean isLocked(Directory directory)
                        throws java.io.IOException

Returns true iff the index in the named directory is currently locked.

Parameters:

directory - the directory to check for a lock

Throws:

java.io.IOException - if there is a low-level IO error

isLocked

public static boolean isLocked(java.lang.String directory)
                        throws java.io.IOException

Returns true iff the index in the named directory is currently locked.

Parameters:

directory - the directory to check for a lock

Throws:

java.io.IOException - if there is a low-level IO error

unlock

public static void unlock(Directory directory)
                   throws java.io.IOException

Forcibly unlocks the index in the named directory.

Caution: this should only be used by failure recovery code, when it is known that no other process nor thread is in fact currently accessing this index.

Throws:

java.io.IOException

main

public static void main(java.lang.String[] args)

Prints the filename and size of each file within a given compound file. Add the -extract flag to extract files to the current working directory. In order to make the extracted version of the index work, you have to copy the segments file from the compound index into the directory where the extracted files are stored.

Parameters:

args - Usage: org.apache.lucene.index.IndexReader [-extract] <cfsfile>