org.apache.lucene.analysis.snowball
Class SnowballFilter
java.lang.Object
org.apache.lucene.util.AttributeSource
org.apache.lucene.analysis.TokenStream
org.apache.lucene.analysis.TokenFilter
org.apache.lucene.analysis.snowball.SnowballFilter
public class SnowballFilter
- extends TokenFilter
A filter that stems words using a Snowball-generated stemmer.
Available stemmers are listed in org.tartarus.snowball.ext
.
Method Summary |
boolean |
incrementToken()
Returns the next input Token, after being stemmed |
Token |
next()
Deprecated. Will be removed in Lucene 3.0. This method is final, as it should
not be overridden. Delegates to the backwards compatibility layer. |
Token |
next(Token reusableToken)
Deprecated. Will be removed in Lucene 3.0. This method is final, as it should
not be overridden. Delegates to the backwards compatibility layer. |
Methods inherited from class org.apache.lucene.util.AttributeSource |
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, restoreState, toString |
SnowballFilter
public SnowballFilter(TokenStream input,
SnowballProgram stemmer)
SnowballFilter
public SnowballFilter(TokenStream in,
String name)
- Construct the named stemming filter.
Available stemmers are listed in
org.tartarus.snowball.ext
.
The name of a stemmer is the part of the class name before "Stemmer",
e.g., the stemmer in EnglishStemmer
is named "English".
- Parameters:
in
- the input tokens to stemname
- the name of a stemmer
incrementToken
public final boolean incrementToken()
throws IOException
- Returns the next input Token, after being stemmed
- Overrides:
incrementToken
in class TokenStream
- Returns:
- false for end of stream; true otherwise
Note that this method will be defined abstract in Lucene
3.0.
- Throws:
IOException
next
public final Token next(Token reusableToken)
throws IOException
- Deprecated. Will be removed in Lucene 3.0. This method is final, as it should
not be overridden. Delegates to the backwards compatibility layer.
- Description copied from class:
TokenStream
- Returns the next token in the stream, or null at EOS. When possible, the
input Token should be used as the returned Token (this gives fastest
tokenization performance), but this is not required and a new Token may be
returned. Callers may re-use a single Token instance for successive calls
to this method.
This implicitly defines a "contract" between consumers (callers of this
method) and producers (implementations of this method that are the source
for tokens):
- A consumer must fully consume the previously returned
Token
before calling this method again.
- A producer must call
Token.clear()
before setting the fields in
it and returning it
Also, the producer must make no assumptions about a Token
after it
has been returned: the caller may arbitrarily change it. If the producer
needs to hold onto the Token
for subsequent calls, it must clone()
it before storing it. Note that a TokenFilter
is considered a
consumer.
- Overrides:
next
in class TokenStream
- Parameters:
reusableToken
- a Token
that may or may not be used to return;
this parameter should never be null (the callee is not required to
check for null before using it, but it is a good idea to assert that
it is not null.)
- Returns:
- next
Token
in the stream or null if end-of-stream was hit
- Throws:
IOException
next
public final Token next()
throws IOException
- Deprecated. Will be removed in Lucene 3.0. This method is final, as it should
not be overridden. Delegates to the backwards compatibility layer.
- Description copied from class:
TokenStream
- Returns the next
Token
in the stream, or null at EOS.
- Overrides:
next
in class TokenStream
- Throws:
IOException
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