Soprano 2.9.4
Soprano::Index::CLuceneIndex Class Reference

The CLuceneIndex provides a wrapper around a CLucene index which stores RDF statements. More...

#include <Soprano/Index/CLuceneIndex>

+ Inheritance diagram for Soprano::Index::CLuceneIndex:

Public Member Functions

 CLuceneIndex (lucene::analysis::Analyzer *analyzer=0)
 
 ~CLuceneIndex ()
 
bool open (const QString &folder, bool force=false)
 
void close ()
 
bool isOpen () const
 
void setQueryAnalyzer (lucene::analysis::Analyzer *analyzer)
 
lucene::analysis::Analyzer * queryAnalyzer () const
 
int resourceCount () const
 
int startTransaction ()
 
bool closeTransaction (int id)
 
Error::ErrorCode addStatement (const Soprano::Statement &)
 
Error::ErrorCode removeStatement (const Soprano::Statement &)
 
lucene::document::Document * documentForResource (const Node &resource)
 
Iterator< QueryHitsearch (const QString &query)
 
Iterator< QueryHitsearch (lucene::search::Query *query)
 
void dump (QTextStream &) const
 
void clear ()
 
void optimize ()
 
- Public Member Functions inherited from Soprano::Error::ErrorCache
virtual ~ErrorCache ()
 
virtual Error lastError () const
 

Static Public Member Functions

static Soprano::Node getResource (lucene::document::Document *document)
 
static QString defaultSearchField ()
 

Additional Inherited Members

- Protected Member Functions inherited from Soprano::Error::ErrorCache
 ErrorCache ()
 
void clearError () const
 
void setError (const Error &) const
 
void setError (const QString &errorMessage, int code=ErrorUnknown) const
 

Detailed Description

The CLuceneIndex provides a wrapper around a CLucene index which stores RDF statements.

It is used by the IndexFilterModel to actually handle the index. It has been made visible in the public API to provide the possibility for advanced queries and data modifications.

CLuceneIndex is thread-safe.

Data organization

In the Soprano index each resource gets its own clucene document. Only statements with literal objects are indexed. The clucene is identified through the statements' subject and then a new field is created that uses the statement's predicate as field name and the statement's object as value. The index ignores all context information.

Warning
The API is subject to change. Most likely CLucene classes will be wrapped and hidden from the public API.
Author
Sebastian Trueg trueg.nosp@m.@kde.nosp@m..org

Definition at line 75 of file cluceneindex.h.

Constructor & Destructor Documentation

◆ CLuceneIndex()

Soprano::Index::CLuceneIndex::CLuceneIndex ( lucene::analysis::Analyzer * analyzer = 0)
Parameters
analyzerThe analyzer to be used. If 0 a standard analyzer will be created.

◆ ~CLuceneIndex()

Soprano::Index::CLuceneIndex::~CLuceneIndex ( )

Destructor.

Calls close().

Member Function Documentation

◆ open()

bool Soprano::Index::CLuceneIndex::open ( const QString & folder,
bool force = false )

Open the index.

Parameters
folderThe folder where the index is stored.
forceIf true any CLucene locks on the folder are removed. This is useful if a previous session crashed and left an unused lock lying around.

◆ close()

void Soprano::Index::CLuceneIndex::close ( )

Close the index. Write back any changes, close any open transactions. (Is called in ~CLuceneIndex())

◆ isOpen()

bool Soprano::Index::CLuceneIndex::isOpen ( ) const
Returns
true If the index has been opened successfully.
See also
open()

◆ setQueryAnalyzer()

void Soprano::Index::CLuceneIndex::setQueryAnalyzer ( lucene::analysis::Analyzer * analyzer)

Optionally set the analyzer to be used for query parsing. By default the index analyzer specified in the constructor is used.

CLuceneIndex will not take ownership of the analyzer.

See also
search(const QString&)
Since
2.3

◆ queryAnalyzer()

lucene::analysis::Analyzer * Soprano::Index::CLuceneIndex::queryAnalyzer ( ) const

Get the query analyzer set in setQueryAnalyzer. This method is only provided for convenience.

Returns
The analyzer set in setQueryAnalyzer or 0 if none was set.
Since
2.3

◆ resourceCount()

int Soprano::Index::CLuceneIndex::resourceCount ( ) const

Get the number of indexed resources.

Returns
The number of indexed resoruces or -1 on error (In the case of error lastError() provides more information.

◆ startTransaction()

int Soprano::Index::CLuceneIndex::startTransaction ( )

Start a new transaction. After calling this method multiple fields and statements may be added to the index and nothing is written back to disk. A transaction has to be closed. Otherwise the data will not be written to the index. (All transactions are closed on deletion.)

Methods such as addStatement will start and close a transaction internally if none has been started before.

Returns
A transaction id that has to be used to close the transaction. This is a safety mechanism to ensure that no other user closes one's transaction. If another transaction has already been started 0 is returned.

◆ closeTransaction()

bool Soprano::Index::CLuceneIndex::closeTransaction ( int id)

Close a transaction and write the changes back to the index.

Parameters
idThe transaction ID as returned by startTransaction()
Returns
true if the transaction was closed, false if no transaction was started, a wrong transaction id has been supplied, or a clucene error occured.

◆ addStatement()

Error::ErrorCode Soprano::Index::CLuceneIndex::addStatement ( const Soprano::Statement & )

Indexes a statement.

Returns
An error code or 0 on success

◆ removeStatement()

Error::ErrorCode Soprano::Index::CLuceneIndex::removeStatement ( const Soprano::Statement & )

Removes a statement from the index.

Returns
An error code or 0 on success

◆ documentForResource()

lucene::document::Document * Soprano::Index::CLuceneIndex::documentForResource ( const Node & resource)

Get a document for a specific resource. This is only possible after starting a transaction.

Parameters
resourceThe resource for which a document is requested.
Returns
The document representing the resource or 0 if no transaction has been started or a clucene error occured.
Warning
This is an advanced method. Calling this method is thread-safe but using the returned document is not.

◆ search() [1/2]

Iterator< QueryHit > Soprano::Index::CLuceneIndex::search ( const QString & query)

Evaluates the given query. Each hit is a resource and a score. Resource properties may be read from the model.

Parameters
queryThe query in the CLucene query language.
Returns
The results as an iterator over QueryHit objects or an invalid iterator on error.

◆ search() [2/2]

Iterator< QueryHit > Soprano::Index::CLuceneIndex::search ( lucene::search::Query * query)

Evaluates the given query. Each hit is a resource and a score. Resource properties may be read from the model.

Parameters
queryThe query to evaluate. The iterator takes ownership of the query. Do not delete.it! (If anyone using this understands the weird CLucene memory management enough to fix this issue, please...)
Returns
The results as an iterator over QueryHit objects or an invalid iterator on error.
Warning
The result iterator uses the query object.

◆ getResource()

static Soprano::Node Soprano::Index::CLuceneIndex::getResource ( lucene::document::Document * document)
static

Returns the Resource corresponding with the specified Document.

◆ defaultSearchField()

static QString Soprano::Index::CLuceneIndex::defaultSearchField ( )
static

This is a temporary method which supports the advanced query interface based on CLucene classes.

The Soprano index creates one special field for each indexed resource which contains all data to allow simple queries without property names or URIs.

Returns
The name of the default CLucene search field to be queried when no properties are known.

◆ dump()

void Soprano::Index::CLuceneIndex::dump ( QTextStream & ) const

Dump the index contents to the stream

◆ clear()

void Soprano::Index::CLuceneIndex::clear ( )

Clear the index, i.e. delete all entries.

Since
2.1

◆ optimize()

void Soprano::Index::CLuceneIndex::optimize ( )

Optimize the index for search. This makes sense after adding or removing a large number of statements.

Since
2.2

The documentation for this class was generated from the following file: