Class JapaneseCompletionFilter
- All Implemented Interfaces:
Closeable
,AutoCloseable
,Unwrappable<TokenStream>
TokenFilter
that adds Japanese romanized tokens to the term
attribute. Also, this keeps original tokens (surface forms). Main usage of this filter is Query
Auto-Completion.
Supported romanization systems: (modified) Hepburn-shiki, Kunrei-shiki (Nihon-shiki) and Wāpuro shiki.
This does not strictly comply with the romanization systems listed above, but tries to cover possible keystroke supported by various Input Methods. e.g.: Circumflex / Macron representing Chōonpu (長音符) are not supported.
The romanization behaviour changes according to its JapaneseCompletionFilter.Mode
. The default mode is JapaneseCompletionFilter.Mode.INDEX
.
Note: This filter must be applied AFTER half-width and full-width normalization. Please ensure
that a width normalizer such as CJKWidthCharFilter
or
CJKWidthFilter
is included in your analysis chain. IF THE
WIDTH NORMALIZATION IS NOT PERFORMED, THIS DOES NOT WORK AS EXPECTED. See also: JapaneseCompletionAnalyzer
.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate static class
private static class
static enum
Completion modeNested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final JapaneseCompletionFilter.Mode
private boolean
private final OffsetAttribute
private final PositionIncrementAttribute
private final ReadingAttribute
private final CharTermAttribute
private final JapaneseCompletionFilter.CompletionTokenGenerator
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
ConstructorsConstructorDescriptionCreates a newJapaneseCompletionFilter
with default configurationsCreates a newJapaneseCompletionFilter
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Method Summary
Modifier and TypeMethodDescriptionboolean
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token.private void
void
reset()
This method is called by a consumer before it begins consumption usingTokenStream.incrementToken()
.Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, end, 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_MODE
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termAttr
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readingAttr
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posIncAtt
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offsetAtt
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tokenGenerator
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inputStreamConsumed
private boolean inputStreamConsumed
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Constructor Details
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JapaneseCompletionFilter
Creates a newJapaneseCompletionFilter
with default configurations -
JapaneseCompletionFilter
Creates a newJapaneseCompletionFilter
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Method Details
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reset
Description copied from class:TokenFilter
This method is called by a consumer before it begins consumption usingTokenStream.incrementToken()
.Resets this stream to a clean state. Stateful implementations must implement this method so that they can be reused, just as if they had been created fresh.
If you override this method, always call
super.reset()
, otherwise some internal state will not be correctly reset (e.g.,Tokenizer
will throwIllegalStateException
on further usage).NOTE: The default implementation chains the call to the input TokenStream, so be sure to call
super.reset()
when overriding this method.- Overrides:
reset
in classTokenFilter
- Throws:
IOException
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incrementToken
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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mayIncrementToken
- Throws:
IOException
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