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Public Member Functions | Static Public Member Functions | Protected Attributes
Lucene::PorterStemFilter Class Reference

Transforms the token stream as per the Porter stemming algorithm. Note: the input to the stemming filter must already be in lower case, so you will need to use LowerCaseFilter or LowerCaseTokenizer further down the Tokenizer chain in order for this to work properly. More...

#include <PorterStemFilter.h>

+ Inheritance diagram for Lucene::PorterStemFilter:

Public Member Functions

 PorterStemFilter (const TokenStreamPtr &input)
 
virtual ~PorterStemFilter ()
 
virtual String getClassName ()
 
boost::shared_ptr< PorterStemFiltershared_from_this ()
 
virtual bool incrementToken ()
 Consumers (ie., IndexWriter) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriate Attributes with the attributes of the next token.
 
- Public Member Functions inherited from Lucene::TokenFilter
virtual ~TokenFilter ()
 
boost::shared_ptr< TokenFiltershared_from_this ()
 
virtual void end ()
 Performs end-of-stream operations, if any, and calls then end() on the input TokenStream. NOTE: Be sure to call TokenFilter::end() first when overriding this method.
 
virtual void close ()
 Close the input TokenStream.
 
virtual void reset ()
 Reset the filter as well as the input TokenStream.
 
- Public Member Functions inherited from Lucene::TokenStream
virtual ~TokenStream ()
 
boost::shared_ptr< TokenStreamshared_from_this ()
 
- Public Member Functions inherited from Lucene::AttributeSource
 AttributeSource ()
 An AttributeSource using the default attribute factory DefaultAttributeFactory.
 
 AttributeSource (const AttributeSourcePtr &input)
 An AttributeSource that uses the same attributes as the supplied one.
 
 AttributeSource (const AttributeFactoryPtr &factory)
 An AttributeSource using the supplied AttributeFactory for creating new Attribute instances.
 
virtual ~AttributeSource ()
 
boost::shared_ptr< AttributeSourceshared_from_this ()
 
AttributeFactoryPtr getAttributeFactory ()
 returns the used AttributeFactory.
 
template<class ATTR >
boost::shared_ptr< ATTR > addAttribute ()
 This method first checks if an instance of that class is already in this AttributeSource and returns it. Otherwise a new instance is created, added to this AttributeSource and returned.
 
void addAttribute (const String &className, const AttributePtr &attrImpl)
 Adds a custom Attribute instance.
 
bool hasAttributes ()
 Returns true if this AttributeSource has any attributes.
 
template<class ATTR >
bool hasAttribute ()
 Returns true, if this AttributeSource contains the passed-in Attribute.
 
template<class ATTR >
boost::shared_ptr< ATTR > getAttribute ()
 Returns the instance of the passed in Attribute contained in this AttributeSource.
 
void clearAttributes ()
 Resets all Attributes in this AttributeSource by calling AttributeImpl#clear() on each Attribute implementation.
 
AttributeSourceStatePtr captureState ()
 Captures the state of all Attributes. The return value can be passed to restoreState to restore the state of this or another AttributeSource.
 
void restoreState (const AttributeSourceStatePtr &state)
 Restores this state by copying the values of all attribute implementations that this state contains into the attributes implementations of the targetStream. The targetStream must contain a corresponding instance for each argument contained in this state (eg. it is not possible to restore the state of an AttributeSource containing a TermAttribute into a AttributeSource using a Token instance as implementation).
 
virtual int32_t hashCode ()
 Return hash code for this object.
 
virtual bool equals (const LuceneObjectPtr &other)
 Return whether two objects are equal.
 
virtual String toString ()
 Returns a string representation of the object.
 
AttributeSourcePtr cloneAttributes ()
 Performs a clone of all AttributeImpl instances returned in a new AttributeSource instance. This method can be used to eg. create another TokenStream with exactly the same attributes (using AttributeSource(AttributeSource))
 
Collection< AttributePtrgetAttributes ()
 Return a vector of attributes based on currentState.
 
- Public Member Functions inherited from Lucene::LuceneObject
virtual ~LuceneObject ()
 
virtual void initialize ()
 Called directly after instantiation to create objects that depend on this object being fully constructed.
 
virtual LuceneObjectPtr clone (const LuceneObjectPtr &other=LuceneObjectPtr())
 Return clone of this object.
 
virtual int32_t compareTo (const LuceneObjectPtr &other)
 Compare two objects.
 
- Public Member Functions inherited from Lucene::LuceneSync
virtual ~LuceneSync ()
 
virtual SynchronizePtr getSync ()
 Return this object synchronize lock.
 
virtual LuceneSignalPtr getSignal ()
 Return this object signal.
 
virtual void lock (int32_t timeout=0)
 Lock this object using an optional timeout.
 
virtual void unlock ()
 Unlock this object.
 
virtual bool holdsLock ()
 Returns true if this object is currently locked by current thread.
 
virtual void wait (int32_t timeout=0)
 Wait for signal using an optional timeout.
 
virtual void notifyAll ()
 Notify all threads waiting for signal.
 

Static Public Member Functions

static String _getClassName ()
 
- Static Public Member Functions inherited from Lucene::TokenFilter
static String _getClassName ()
 
- Static Public Member Functions inherited from Lucene::TokenStream
static String _getClassName ()
 
- Static Public Member Functions inherited from Lucene::AttributeSource
static String _getClassName ()
 

Protected Attributes

PorterStemmerPtr stemmer
 
TermAttributePtr termAtt
 
- Protected Attributes inherited from Lucene::TokenFilter
TokenStreamPtr input
 The source of tokens for this filter.
 
- Protected Attributes inherited from Lucene::AttributeSource
AttributeFactoryPtr factory
 
MapStringAttribute attributes
 
AttributeSourceStatePtr currentState
 
- Protected Attributes inherited from Lucene::LuceneSync
SynchronizePtr objectLock
 
LuceneSignalPtr objectSignal
 

Additional Inherited Members

- Protected Member Functions inherited from Lucene::TokenFilter
 TokenFilter (const TokenStreamPtr &input)
 Construct a token stream filtering the given input.
 
- Protected Member Functions inherited from Lucene::TokenStream
 TokenStream ()
 A TokenStream using the default attribute factory.
 
 TokenStream (const AttributeSourcePtr &input)
 A TokenStream that uses the same attributes as the supplied one.
 
 TokenStream (const AttributeFactoryPtr &factory)
 A TokenStream using the supplied AttributeFactory for creating new Attribute instances.
 
- Protected Member Functions inherited from Lucene::AttributeSource
AttributePtr getAttribute (const String &className)
 The caller must pass in a className value. This method checks if an instance of that class is already in this AttributeSource and returns it.
 
bool hasAttribute (const String &className)
 Returns true, if this AttributeSource contains the passed-in Attribute.
 
void computeCurrentState ()
 
- Protected Member Functions inherited from Lucene::LuceneObject
 LuceneObject ()
 

Detailed Description

Transforms the token stream as per the Porter stemming algorithm. Note: the input to the stemming filter must already be in lower case, so you will need to use LowerCaseFilter or LowerCaseTokenizer further down the Tokenizer chain in order for this to work properly.

To use this filter with other analyzers, you'll want to write an Analyzer class that sets up the TokenStream chain as you want it. To use this with LowerCaseTokenizer, for example, you'd write an analyzer like this:

class MyAnalyzer : public Analyzer
{
public:
    virtual TokenStreamPtr tokenStream(const String& fieldName, const ReaderPtr& reader)
    {
        return newLucene<PorterStemFilter>(newLucene<LowerCaseTokenizer>(reader));
    }
};

Constructor & Destructor Documentation

◆ PorterStemFilter()

Lucene::PorterStemFilter::PorterStemFilter ( const TokenStreamPtr input)

◆ ~PorterStemFilter()

virtual Lucene::PorterStemFilter::~PorterStemFilter ( )
virtual

Member Function Documentation

◆ _getClassName()

static String Lucene::PorterStemFilter::_getClassName ( )
inlinestatic

◆ getClassName()

virtual String Lucene::PorterStemFilter::getClassName ( )
inlinevirtual

Reimplemented from Lucene::TokenFilter.

◆ incrementToken()

virtual bool Lucene::PorterStemFilter::incrementToken ( )
virtual

Consumers (ie., IndexWriter) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriate Attributes with the attributes of the next token.

The producer must make no assumptions about the attributes after the method has been returned: the caller may arbitrarily change it. If the producer needs to preserve the state for subsequent calls, it can use captureState to create a copy of the current attribute state.

This method is called for every token of a document, so an efficient implementation is crucial for good performance. To avoid calls to addAttribute(Class) and getAttribute(Class), references to all Attributes that this stream uses should be retrieved during instantiation.

To ensure that filters and consumers know which attributes are available, the attributes must be added during instantiation. Filters and consumers are not required to check for availability of attributes in incrementToken().

Returns
false for end of stream; true otherwise

Implements Lucene::TokenStream.

◆ shared_from_this()

boost::shared_ptr< PorterStemFilter > Lucene::PorterStemFilter::shared_from_this ( )
inline

Field Documentation

◆ stemmer

PorterStemmerPtr Lucene::PorterStemFilter::stemmer
protected

◆ termAtt

TermAttributePtr Lucene::PorterStemFilter::termAtt
protected

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

clucene.sourceforge.net