Class GraphTokenFilter
- All Implemented Interfaces:
Closeable,AutoCloseable,Unwrappable<TokenStream>
Call incrementBaseToken() to move the root of the graph to the next position in the
TokenStream, incrementGraphToken() to move along the current graph, and incrementGraph() to reset to the next graph based at the current root.
For example, given the stream 'a b/c:2 d e`, then with the base token at 'a', incrementGraphToken() will produce the stream 'a b d e', and then after calling incrementGraph() will produce the stream 'a c e'.
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Nested Class Summary
Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State -
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final intThe maximum permitted number of routes through a graphstatic final intThe maximum permitted read-ahead in the token streamFields inherited from class org.apache.lucene.analysis.TokenFilter
inputFields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoidend()This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()returnedfalse(using the newTokenStreamAPI).intReturn the number of trailing positions at the end of the graphprotected final booleanMove the root of the graph to the next token in the wrapped TokenStreamprotected final booleanReset to the root token again, and move down the next route through the graphprotected final booleanMove to the next token in the current route through the graphvoidreset()This method is called by a consumer before it begins consumption usingTokenStream.incrementToken().Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, unwrapMethods inherited from class org.apache.lucene.analysis.TokenStream
incrementTokenMethods 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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MAX_GRAPH_STACK_SIZE
public static final int MAX_GRAPH_STACK_SIZEThe maximum permitted number of routes through a graph- See Also:
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MAX_TOKEN_CACHE_SIZE
public static final int MAX_TOKEN_CACHE_SIZEThe maximum permitted read-ahead in the token stream- See Also:
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Constructor Details
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GraphTokenFilter
Create a new GraphTokenFilter
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Method Details
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incrementBaseToken
Move the root of the graph to the next token in the wrapped TokenStream- Returns:
falseif the underlying stream is exhausted- Throws:
IOException
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incrementGraphToken
Move to the next token in the current route through the graph- Returns:
falseif there are not more tokens in the current graph- Throws:
IOException
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incrementGraph
Reset to the root token again, and move down the next route through the graph- Returns:
- false if there are no more routes through the graph
- Throws:
IOException
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getTrailingPositions
public int getTrailingPositions()Return the number of trailing positions at the end of the graphNB this should only be called after
incrementGraphToken()has returnedfalse -
end
Description copied from class:TokenFilterThis method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()returnedfalse(using the newTokenStreamAPI). 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 a WhitespaceTokenizer was used.
Additionally any skipped positions (such as those removed by a stopfilter) can be applied to the position increment, or any adjustment of other attributes where the end-of-stream value may be important.
If you override this method, always call
super.end().NOTE: The default implementation chains the call to the input TokenStream, so be sure to call
super.end()first when overriding this method.- Overrides:
endin classTokenFilter- Throws:
IOException- If an I/O error occurs
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reset
Description copied from class:TokenFilterThis 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.,Tokenizerwill throwIllegalStateExceptionon 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:
resetin classTokenFilter- Throws:
IOException
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