Class CapitalizationFilter
- 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.TokenFilter
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- org.apache.lucene.analysis.miscellaneous.CapitalizationFilter
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- All Implemented Interfaces:
Closeable
,AutoCloseable
public final class CapitalizationFilter extends TokenFilter
A filter to apply normal capitalization rules to Tokens. It will make the first letter capital and the rest lower case. This filter is particularly useful to build nice looking facet parameters. This filter is not appropriate if you intend to use a prefix query.
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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
DEFAULT_MAX_TOKEN_LENGTH
static int
DEFAULT_MAX_WORD_COUNT
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Constructor Summary
Constructors Constructor Description CapitalizationFilter(TokenStream in)
Creates a CapitalizationFilter with the default parameters.CapitalizationFilter(TokenStream in, boolean onlyFirstWord, CharArraySet keep, boolean forceFirstLetter, Collection<char[]> okPrefix, int minWordLength, int maxWordCount, int maxTokenLength)
Creates a CapitalizationFilter with the specified parameters.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
incrementToken()
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token.-
Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, end, 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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DEFAULT_MAX_WORD_COUNT
public static final int DEFAULT_MAX_WORD_COUNT
- See Also:
- Constant Field Values
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DEFAULT_MAX_TOKEN_LENGTH
public static final int DEFAULT_MAX_TOKEN_LENGTH
- See Also:
- Constant Field Values
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Constructor Detail
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CapitalizationFilter
public CapitalizationFilter(TokenStream in)
Creates a CapitalizationFilter with the default parameters.
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CapitalizationFilter
public CapitalizationFilter(TokenStream in, boolean onlyFirstWord, CharArraySet keep, boolean forceFirstLetter, Collection<char[]> okPrefix, int minWordLength, int maxWordCount, int maxTokenLength)
Creates a CapitalizationFilter with the specified parameters.- Parameters:
in
- input tokenstreamonlyFirstWord
- should each word be capitalized or all of the words?keep
- a keep word list. Each word that should be kept separated by whitespace.forceFirstLetter
- Force the first letter to be capitalized even if it is in the keep list.okPrefix
- do not change word capitalization if a word begins with something in this list.minWordLength
- how long the word needs to be to get capitalization applied. If the minWordLength is 3, "and" > "And" but "or" stays "or".maxWordCount
- if the token contains more then maxWordCount words, the capitalization is assumed to be correct.maxTokenLength
- ???
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Method Detail
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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 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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