Class ClassicTokenizer
- java.lang.Object
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- org.apache.lucene.util.AttributeSource
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- org.apache.lucene.analysis.TokenStream
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- org.apache.lucene.analysis.Tokenizer
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- org.apache.lucene.analysis.standard.ClassicTokenizer
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public final class ClassicTokenizer extends Tokenizer
A grammar-based tokenizer constructed with JFlexThis should be a good tokenizer for most European-language documents:
- Splits words at punctuation characters, removing punctuation. However, a dot that's not followed by whitespace is considered part of a token.
- Splits words at hyphens, unless there's a number in the token, in which case the whole token is interpreted as a product number and is not split.
- Recognizes email addresses and internet hostnames as one token.
Many applications have specific tokenizer needs. If this tokenizer does not suit your application, please consider copying this source code directory to your project and maintaining your own grammar-based tokenizer.
You must specify the required
Version
compatibility when creating ClassicAnalyzer:- As of 2.4, Tokens incorrectly identified as acronyms are corrected (see LUCENE-1608
StandardTokenizer
implements Unicode text segmentation, as specified by UAX#29.
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.AttributeFactory, AttributeSource.State
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Field Summary
Fields Modifier and Type Field Description static int
ACRONYM
static int
ACRONYM_DEP
Deprecated.this solves a bug where HOSTs that end with '.' are identified as ACRONYMs.static int
ALPHANUM
static int
APOSTROPHE
static int
CJ
static int
COMPANY
static int
EMAIL
static int
HOST
static int
NUM
static String[]
TOKEN_TYPES
String token types that correspond to token type int constants
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Constructor Summary
Constructors Constructor Description ClassicTokenizer(Version matchVersion, Reader input)
Creates a new instance of theClassicTokenizer
.ClassicTokenizer(Version matchVersion, AttributeSource.AttributeFactory factory, Reader input)
Creates a new ClassicTokenizer with a givenAttributeSource.AttributeFactory
ClassicTokenizer(Version matchVersion, AttributeSource source, Reader input)
Creates a new ClassicTokenizer with a givenAttributeSource
.
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Method Summary
All Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description void
end()
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
API).int
getMaxTokenLength()
boolean
incrementToken()
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token.boolean
isReplaceInvalidAcronym()
Deprecated.Remove in 3.X and make true the only valid valuevoid
reset(Reader reader)
Expert: Reset the tokenizer to a new reader.void
setMaxTokenLength(int length)
Set the max allowed token length.void
setReplaceInvalidAcronym(boolean replaceInvalidAcronym)
Deprecated.Remove in 3.X and make true the only valid value See https://issues.apache.org/jira/browse/LUCENE-1068-
Methods inherited from class org.apache.lucene.analysis.Tokenizer
close, correctOffset
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Methods inherited from class org.apache.lucene.analysis.TokenStream
reset
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Methods inherited from class org.apache.lucene.util.AttributeSource
addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toString
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Field Detail
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ALPHANUM
public static final int ALPHANUM
- See Also:
- Constant Field Values
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APOSTROPHE
public static final int APOSTROPHE
- See Also:
- Constant Field Values
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ACRONYM
public static final int ACRONYM
- See Also:
- Constant Field Values
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COMPANY
public static final int COMPANY
- See Also:
- Constant Field Values
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EMAIL
public static final int EMAIL
- See Also:
- Constant Field Values
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HOST
public static final int HOST
- See Also:
- Constant Field Values
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NUM
public static final int NUM
- See Also:
- Constant Field Values
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CJ
public static final int CJ
- See Also:
- Constant Field Values
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ACRONYM_DEP
@Deprecated public static final int ACRONYM_DEP
Deprecated.this solves a bug where HOSTs that end with '.' are identified as ACRONYMs.- See Also:
- Constant Field Values
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TOKEN_TYPES
public static final String[] TOKEN_TYPES
String token types that correspond to token type int constants
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Constructor Detail
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ClassicTokenizer
public ClassicTokenizer(Version matchVersion, Reader input)
Creates a new instance of theClassicTokenizer
. Attaches theinput
to the newly created JFlex scanner.- Parameters:
input
- The input reader See http://issues.apache.org/jira/browse/LUCENE-1068
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ClassicTokenizer
public ClassicTokenizer(Version matchVersion, AttributeSource source, Reader input)
Creates a new ClassicTokenizer with a givenAttributeSource
.
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ClassicTokenizer
public ClassicTokenizer(Version matchVersion, AttributeSource.AttributeFactory factory, Reader input)
Creates a new ClassicTokenizer with a givenAttributeSource.AttributeFactory
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Method Detail
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setMaxTokenLength
public void setMaxTokenLength(int length)
Set the max allowed token length. Any token longer than this is skipped.
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getMaxTokenLength
public int getMaxTokenLength()
- See Also:
setMaxTokenLength(int)
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incrementToken
public final 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 appropriateAttributeImpl
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)
andAttributeSource.getAttribute(Class)
, references to allAttributeImpl
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()
.- Specified by:
incrementToken
in classTokenStream
- Returns:
- false for end of stream; true otherwise
- Throws:
IOException
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end
public final void end()
Description copied from class:TokenStream
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
API). Streams implementing the old API should upgrade to use this feature. This method can be used to perform any end-of-stream operations, such as setting the final offset of a stream. The final offset of a stream might differ from the offset of the last token eg in case one or more whitespaces followed after the last token, but aWhitespaceTokenizer
was used.- Overrides:
end
in classTokenStream
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reset
public void reset(Reader reader) throws IOException
Description copied from class:Tokenizer
Expert: Reset the tokenizer to a new reader. Typically, an analyzer (in its reusableTokenStream method) will use this to re-use a previously created tokenizer.- Overrides:
reset
in classTokenizer
- Throws:
IOException
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isReplaceInvalidAcronym
@Deprecated public boolean isReplaceInvalidAcronym()
Deprecated.Remove in 3.X and make true the only valid valuePrior to https://issues.apache.org/jira/browse/LUCENE-1068, ClassicTokenizer mischaracterized as acronyms tokens like www.abc.com when they should have been labeled as hosts instead.- Returns:
- true if ClassicTokenizer now returns these tokens as Hosts, otherwise false
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setReplaceInvalidAcronym
@Deprecated public void setReplaceInvalidAcronym(boolean replaceInvalidAcronym)
Deprecated.Remove in 3.X and make true the only valid value See https://issues.apache.org/jira/browse/LUCENE-1068- Parameters:
replaceInvalidAcronym
- Set to true to replace mischaracterized acronyms as HOST.
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