Class CharTokenizer
- 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.util.CharTokenizer
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- All Implemented Interfaces:
Closeable
,AutoCloseable
- Direct Known Subclasses:
LetterTokenizer
,UnicodeWhitespaceTokenizer
,WhitespaceTokenizer
public abstract class CharTokenizer extends Tokenizer
An abstract base class for simple, character-oriented tokenizers.The base class also provides factories to create instances of
CharTokenizer
using Java 8 lambdas or method references. It is possible to create an instance which behaves exactly likeLetterTokenizer
:Tokenizer tok = CharTokenizer.fromTokenCharPredicate(Character::isLetter);
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Nested Class Summary
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Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
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Field Summary
Fields Modifier and Type Field Description static int
DEFAULT_MAX_WORD_LEN
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Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
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Constructor Summary
Constructors Constructor Description CharTokenizer()
Creates a newCharTokenizer
instanceCharTokenizer(AttributeFactory factory)
Creates a newCharTokenizer
instanceCharTokenizer(AttributeFactory factory, int maxTokenLen)
Creates a newCharTokenizer
instance
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Method Summary
All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods Modifier and Type Method Description void
end()
static CharTokenizer
fromSeparatorCharPredicate(IntPredicate separatorCharPredicate)
Creates a new instance of CharTokenizer using a custom predicate, supplied as method reference or lambda expression.static CharTokenizer
fromSeparatorCharPredicate(IntPredicate separatorCharPredicate, IntUnaryOperator normalizer)
Deprecated.Normalization should be done in a subsequent TokenFilterstatic CharTokenizer
fromSeparatorCharPredicate(AttributeFactory factory, IntPredicate separatorCharPredicate)
Creates a new instance of CharTokenizer with the supplied attribute factory using a custom predicate, supplied as method reference or lambda expression.static CharTokenizer
fromSeparatorCharPredicate(AttributeFactory factory, IntPredicate separatorCharPredicate, IntUnaryOperator normalizer)
Deprecated.Normalization should be done in a subsequent TokenFilterstatic CharTokenizer
fromTokenCharPredicate(IntPredicate tokenCharPredicate)
Creates a new instance of CharTokenizer using a custom predicate, supplied as method reference or lambda expression.static CharTokenizer
fromTokenCharPredicate(IntPredicate tokenCharPredicate, IntUnaryOperator normalizer)
Deprecated.Normalization should be done in a subsequent TokenFilterstatic CharTokenizer
fromTokenCharPredicate(AttributeFactory factory, IntPredicate tokenCharPredicate)
Creates a new instance of CharTokenizer with the supplied attribute factory using a custom predicate, supplied as method reference or lambda expression.static CharTokenizer
fromTokenCharPredicate(AttributeFactory factory, IntPredicate tokenCharPredicate, IntUnaryOperator normalizer)
Deprecated.Normalization should be done in a subsequent TokenFilterboolean
incrementToken()
protected abstract boolean
isTokenChar(int c)
Returns true iff a codepoint should be included in a token.protected int
normalize(int c)
Deprecated.Normalization should be done in a subsequent TokenFiltervoid
reset()
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Methods inherited from class org.apache.lucene.analysis.Tokenizer
close, correctOffset, setReader
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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 Detail
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DEFAULT_MAX_WORD_LEN
public static final int DEFAULT_MAX_WORD_LEN
- See Also:
- Constant Field Values
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Constructor Detail
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CharTokenizer
public CharTokenizer()
Creates a newCharTokenizer
instance
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CharTokenizer
public CharTokenizer(AttributeFactory factory)
Creates a newCharTokenizer
instance- Parameters:
factory
- the attribute factory to use for thisTokenizer
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CharTokenizer
public CharTokenizer(AttributeFactory factory, int maxTokenLen)
Creates a newCharTokenizer
instance- Parameters:
factory
- the attribute factory to use for thisTokenizer
maxTokenLen
- maximum token length the tokenizer will emit. Must be greater than 0 and less than MAX_TOKEN_LENGTH_LIMIT (1024*1024)- Throws:
IllegalArgumentException
- if maxTokenLen is invalid.
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Method Detail
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fromTokenCharPredicate
public static CharTokenizer fromTokenCharPredicate(IntPredicate tokenCharPredicate)
Creates a new instance of CharTokenizer using a custom predicate, supplied as method reference or lambda expression. The predicate should returntrue
for all valid token characters.This factory is intended to be used with lambdas or method references. E.g., an elegant way to create an instance which behaves exactly as
LetterTokenizer
is:Tokenizer tok = CharTokenizer.fromTokenCharPredicate(Character::isLetter);
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fromTokenCharPredicate
public static CharTokenizer fromTokenCharPredicate(AttributeFactory factory, IntPredicate tokenCharPredicate)
Creates a new instance of CharTokenizer with the supplied attribute factory using a custom predicate, supplied as method reference or lambda expression. The predicate should returntrue
for all valid token characters.This factory is intended to be used with lambdas or method references. E.g., an elegant way to create an instance which behaves exactly as
LetterTokenizer
is:Tokenizer tok = CharTokenizer.fromTokenCharPredicate(factory, Character::isLetter);
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fromTokenCharPredicate
@Deprecated public static CharTokenizer fromTokenCharPredicate(IntPredicate tokenCharPredicate, IntUnaryOperator normalizer)
Deprecated.Normalization should be done in a subsequent TokenFilterCreates a new instance of CharTokenizer using a custom predicate, supplied as method reference or lambda expression. The predicate should returntrue
for all valid token characters. This factory also takes a function to normalize chars, e.g., lowercasing them, supplied as method reference or lambda expression.This factory is intended to be used with lambdas or method references. E.g., an elegant way to create an instance which behaves exactly as
LowerCaseTokenizer
is:Tokenizer tok = CharTokenizer.fromTokenCharPredicate(Character::isLetter, Character::toLowerCase);
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fromTokenCharPredicate
@Deprecated public static CharTokenizer fromTokenCharPredicate(AttributeFactory factory, IntPredicate tokenCharPredicate, IntUnaryOperator normalizer)
Deprecated.Normalization should be done in a subsequent TokenFilterCreates a new instance of CharTokenizer with the supplied attribute factory using a custom predicate, supplied as method reference or lambda expression. The predicate should returntrue
for all valid token characters. This factory also takes a function to normalize chars, e.g., lowercasing them, supplied as method reference or lambda expression.This factory is intended to be used with lambdas or method references. E.g., an elegant way to create an instance which behaves exactly as
LowerCaseTokenizer
is:Tokenizer tok = CharTokenizer.fromTokenCharPredicate(factory, Character::isLetter, Character::toLowerCase);
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fromSeparatorCharPredicate
public static CharTokenizer fromSeparatorCharPredicate(IntPredicate separatorCharPredicate)
Creates a new instance of CharTokenizer using a custom predicate, supplied as method reference or lambda expression. The predicate should returntrue
for all valid token separator characters. This method is provided for convenience to easily use predicates that are negated (they match the separator characters, not the token characters).This factory is intended to be used with lambdas or method references. E.g., an elegant way to create an instance which behaves exactly as
WhitespaceTokenizer
is:Tokenizer tok = CharTokenizer.fromSeparatorCharPredicate(Character::isWhitespace);
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fromSeparatorCharPredicate
public static CharTokenizer fromSeparatorCharPredicate(AttributeFactory factory, IntPredicate separatorCharPredicate)
Creates a new instance of CharTokenizer with the supplied attribute factory using a custom predicate, supplied as method reference or lambda expression. The predicate should returntrue
for all valid token separator characters.This factory is intended to be used with lambdas or method references. E.g., an elegant way to create an instance which behaves exactly as
WhitespaceTokenizer
is:Tokenizer tok = CharTokenizer.fromSeparatorCharPredicate(factory, Character::isWhitespace);
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fromSeparatorCharPredicate
@Deprecated public static CharTokenizer fromSeparatorCharPredicate(IntPredicate separatorCharPredicate, IntUnaryOperator normalizer)
Deprecated.Normalization should be done in a subsequent TokenFilterCreates a new instance of CharTokenizer using a custom predicate, supplied as method reference or lambda expression. The predicate should returntrue
for all valid token separator characters. This factory also takes a function to normalize chars, e.g., lowercasing them, supplied as method reference or lambda expression.This factory is intended to be used with lambdas or method references. E.g., an elegant way to create an instance which behaves exactly as the combination
WhitespaceTokenizer
andLowerCaseFilter
is:Tokenizer tok = CharTokenizer.fromSeparatorCharPredicate(Character::isWhitespace, Character::toLowerCase);
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fromSeparatorCharPredicate
@Deprecated public static CharTokenizer fromSeparatorCharPredicate(AttributeFactory factory, IntPredicate separatorCharPredicate, IntUnaryOperator normalizer)
Deprecated.Normalization should be done in a subsequent TokenFilterCreates a new instance of CharTokenizer with the supplied attribute factory using a custom predicate. The predicate should returntrue
for all valid token separator characters. This factory also takes a function to normalize chars, e.g., lowercasing them, supplied as method reference or lambda expression.This factory is intended to be used with lambdas or method references. E.g., an elegant way to create an instance which behaves exactly as
WhitespaceTokenizer
andLowerCaseFilter
is:Tokenizer tok = CharTokenizer.fromSeparatorCharPredicate(factory, Character::isWhitespace, Character::toLowerCase);
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isTokenChar
protected abstract boolean isTokenChar(int c)
Returns true iff a codepoint should be included in a token. This tokenizer generates as tokens adjacent sequences of codepoints which satisfy this predicate. Codepoints for which this is false are used to define token boundaries and are not included in tokens.
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normalize
@Deprecated protected int normalize(int c)
Deprecated.Normalization should be done in a subsequent TokenFilterCalled on each token character to normalize it before it is added to the token. The default implementation does nothing. Subclasses may use this to, e.g., lowercase tokens.
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incrementToken
public final boolean incrementToken() throws IOException
- Specified by:
incrementToken
in classTokenStream
- Throws:
IOException
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end
public final void end() throws IOException
- Overrides:
end
in classTokenStream
- Throws:
IOException
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reset
public void reset() throws IOException
- Overrides:
reset
in classTokenizer
- Throws:
IOException
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