| java.lang.Object | ||||
| ↳ | org.apache.lucene.util.AttributeSource | |||
| ↳ | org.apache.lucene.analysis.TokenStream | |||
| ↳ | org.apache.lucene.analysis.TokenFilter | |||
| ↳ | org.apache.lucene.analysis.CachingTokenFilter | |||
Class Overview
This class can be used if the token attributes of a TokenStream are intended to be consumed more than once. It caches all token attribute states locally in a List.
CachingTokenFilter implements the optional method
reset(), which repositions the
stream to the first Token.
Summary
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Inherited Fields | |||||||||||
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 From class
org.apache.lucene.analysis.TokenFilter
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Performs end-of-stream operations, if any, and calls then
end() on the
input TokenStream. | |||||||||||
Consumers (i.e.,
IndexWriter) use this method to advance the stream to
the next token. | |||||||||||
Reset the filter as well as the input TokenStream.
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Inherited Methods | |||||||||||
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From class
org.apache.lucene.analysis.TokenFilter
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From class
org.apache.lucene.analysis.TokenStream
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From class
org.apache.lucene.util.AttributeSource
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From class
java.lang.Object
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From interface
java.io.Closeable
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Public Constructors
Public Methods
public final void end ()
Performs end-of-stream operations, if any, and calls then end() on the
input TokenStream.
super.end() first when overriding this method.Throws
| IOException |
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public final boolean incrementToken ()
Consumers (i.e., IndexWriter) use this method to advance the stream to
the next token. Implementing classes must implement this method and update
the appropriate AttributeImpls 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
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
addAttribute(Class) and getAttribute(Class),
references to all AttributeImpls 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
incrementToken().
Returns
- false for end of stream; true otherwise
Throws
| IOException |
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