org.apache.lucene.analysis.de
Class GermanStemFilter
java.lang.Object
org.apache.lucene.util.AttributeSource
org.apache.lucene.analysis.TokenStream
org.apache.lucene.analysis.TokenFilter
org.apache.lucene.analysis.de.GermanStemFilter
public final class GermanStemFilter
- extends TokenFilter
A TokenFilter
that stems German words.
It supports a table of words that should
not be stemmed at all. The stemmer used can be changed at runtime after the
filter object is created (as long as it is a GermanStemmer
).
- Version:
- $Id: GermanStemFilter.java 805400 2009-08-18 12:55:26Z rmuir $
Methods inherited from class org.apache.lucene.util.AttributeSource |
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, restoreState, toString |
GermanStemFilter
public GermanStemFilter(TokenStream in)
GermanStemFilter
public GermanStemFilter(TokenStream in,
Set exclusionSet)
- Builds a GermanStemFilter that uses an exclusion table.
incrementToken
public boolean incrementToken()
throws IOException
- Description copied from class:
TokenStream
- Consumers (i.e.,
IndexWriter
) use this method to advance the stream to
the next token. Implementing classes must implement this method and update
the appropriate AttributeImpl
s 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
AttributeSource.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
AttributeSource.addAttribute(Class)
and AttributeSource.getAttribute(Class)
or downcasts,
references to all AttributeImpl
s 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
TokenStream.incrementToken()
.
- Overrides:
incrementToken
in class TokenStream
- Returns:
- Returns true for next token in the stream, or false at EOS
- Throws:
IOException
setStemmer
public void setStemmer(GermanStemmer stemmer)
- Set a alternative/custom
GermanStemmer
for this filter.
setExclusionSet
public void setExclusionSet(Set exclusionSet)
- Set an alternative exclusion list for this filter.
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