Class ShingleFilter
java.lang.Object
org.apache.lucene.util.AttributeSource
org.apache.lucene.analysis.TokenStream
org.apache.lucene.analysis.TokenFilter
org.apache.lucene.analysis.shingle.ShingleFilter
- All Implemented Interfaces:
Closeable
,AutoCloseable
,Unwrappable<TokenStream>
A ShingleFilter constructs shingles (token n-grams) from a token stream. In other words, it
creates combinations of tokens as a single token.
For example, the sentence "please divide this sentence into shingles" might be tokenized into shingles "please divide", "divide this", "this sentence", "sentence into", and "into shingles".
This filter handles position increments > 1 by inserting filler tokens (tokens with termtext "_"). It does not handle a position increment of 0.
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Nested Class Summary
Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
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Field Summary
Modifier and TypeFieldDescriptionstatic final String
filler token for when positionIncrement is more than 1static final int
default maximum shingle size is 2.static final int
default minimum shingle size is 2.static final String
The default string to use when joining adjacent tokens to form a shinglestatic final String
default token type attribute value is "shingle"Fields inherited from class org.apache.lucene.analysis.TokenFilter
input
Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
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Constructor Summary
ConstructorDescriptionShingleFilter
(TokenStream input) Construct a ShingleFilter with default shingle size: 2.ShingleFilter
(TokenStream input, int maxShingleSize) Constructs a ShingleFilter with the specified shingle size from theTokenStream
input
ShingleFilter
(TokenStream input, int minShingleSize, int maxShingleSize) Constructs a ShingleFilter with the specified shingle size from theTokenStream
input
ShingleFilter
(TokenStream input, String tokenType) Construct a ShingleFilter with the specified token type for shingle tokens and the default shingle size: 2 -
Method Summary
Modifier and TypeMethodDescriptionvoid
end()
boolean
void
reset()
void
setFillerToken
(String fillerToken) Sets the string to insert for each position at which there is no token (i.e., when position increment is greater than one).void
setMaxShingleSize
(int maxShingleSize) Set the max shingle size (default: 2)void
setMinShingleSize
(int minShingleSize) Set the min shingle size (default: 2).void
setOutputUnigrams
(boolean outputUnigrams) Shall the output stream contain the input tokens (unigrams) as well as shingles? (default: true.)void
setOutputUnigramsIfNoShingles
(boolean outputUnigramsIfNoShingles) Shall we override the behavior of outputUnigrams==false for those times when no shingles are available (because there are fewer than minShingleSize tokens in the input stream)? (default: false.)void
setTokenSeparator
(String tokenSeparator) Sets the string to use when joining adjacent tokens to form a shinglevoid
setTokenType
(String tokenType) Set the type of the shingle tokens produced by this filter.Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, unwrap
Methods inherited from class org.apache.lucene.util.AttributeSource
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toString
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Field Details
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DEFAULT_FILLER_TOKEN
filler token for when positionIncrement is more than 1- See Also:
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DEFAULT_MAX_SHINGLE_SIZE
public static final int DEFAULT_MAX_SHINGLE_SIZEdefault maximum shingle size is 2.- See Also:
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DEFAULT_MIN_SHINGLE_SIZE
public static final int DEFAULT_MIN_SHINGLE_SIZEdefault minimum shingle size is 2.- See Also:
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DEFAULT_TOKEN_TYPE
default token type attribute value is "shingle"- See Also:
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DEFAULT_TOKEN_SEPARATOR
The default string to use when joining adjacent tokens to form a shingle- See Also:
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Constructor Details
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ShingleFilter
Constructs a ShingleFilter with the specified shingle size from theTokenStream
input
- Parameters:
input
- input streamminShingleSize
- minimum shingle size produced by the filter.maxShingleSize
- maximum shingle size produced by the filter.
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ShingleFilter
Constructs a ShingleFilter with the specified shingle size from theTokenStream
input
- Parameters:
input
- input streammaxShingleSize
- maximum shingle size produced by the filter.
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ShingleFilter
Construct a ShingleFilter with default shingle size: 2.- Parameters:
input
- input stream
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ShingleFilter
Construct a ShingleFilter with the specified token type for shingle tokens and the default shingle size: 2- Parameters:
input
- input streamtokenType
- token type for shingle tokens
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Method Details
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setTokenType
Set the type of the shingle tokens produced by this filter. (default: "shingle")- Parameters:
tokenType
- token tokenType
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setOutputUnigrams
public void setOutputUnigrams(boolean outputUnigrams) Shall the output stream contain the input tokens (unigrams) as well as shingles? (default: true.)- Parameters:
outputUnigrams
- Whether or not the output stream shall contain the input tokens (unigrams)
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setOutputUnigramsIfNoShingles
public void setOutputUnigramsIfNoShingles(boolean outputUnigramsIfNoShingles) Shall we override the behavior of outputUnigrams==false for those times when no shingles are available (because there are fewer than minShingleSize tokens in the input stream)? (default: false.)Note that if outputUnigrams==true, then unigrams are always output, regardless of whether any shingles are available.
- Parameters:
outputUnigramsIfNoShingles
- Whether or not to output a single unigram when no shingles are available.
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setMaxShingleSize
public void setMaxShingleSize(int maxShingleSize) Set the max shingle size (default: 2)- Parameters:
maxShingleSize
- max size of output shingles
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setMinShingleSize
public void setMinShingleSize(int minShingleSize) Set the min shingle size (default: 2).This method requires that the passed in minShingleSize is not greater than maxShingleSize, so make sure that maxShingleSize is set before calling this method.
The unigram output option is independent of the min shingle size.
- Parameters:
minShingleSize
- min size of output shingles
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setTokenSeparator
Sets the string to use when joining adjacent tokens to form a shingle- Parameters:
tokenSeparator
- used to separate input stream tokens in output shingles
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setFillerToken
Sets the string to insert for each position at which there is no token (i.e., when position increment is greater than one).- Parameters:
fillerToken
- string to insert at each position where there is no token
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incrementToken
- Specified by:
incrementToken
in classTokenStream
- Throws:
IOException
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end
- Overrides:
end
in classTokenFilter
- Throws:
IOException
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reset
- Overrides:
reset
in classTokenFilter
- Throws:
IOException
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