Class GraphTokenFilter
- 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.GraphTokenFilter
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
,Unwrappable<TokenStream>
- Direct Known Subclasses:
FixedShingleFilter
public abstract class GraphTokenFilter extends TokenFilter
An abstract TokenFilter that exposes its input stream as a graphCall
incrementBaseToken()
to move the root of the graph to the next position in the TokenStream,incrementGraphToken()
to move along the current graph, andincrementGraph()
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 Modifier and Type Class Description private static class
GraphTokenFilter.Token
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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 private GraphTokenFilter.Token
baseToken
private int
cacheSize
private java.util.List<GraphTokenFilter.Token>
currentGraph
private int
finalOffsets
private int
graphDepth
private int
graphPos
static int
MAX_GRAPH_STACK_SIZE
The maximum permitted number of routes through a graphstatic int
MAX_TOKEN_CACHE_SIZE
The maximum permitted read-ahead in the token streamprivate OffsetAttribute
offsetAtt
private PositionIncrementAttribute
posIncAtt
private int
stackSize
private java.util.Deque<GraphTokenFilter.Token>
tokenPool
private int
trailingPositions
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Fields inherited from class org.apache.lucene.analysis.TokenFilter
input
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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 GraphTokenFilter(TokenStream input)
Create a new GraphTokenFilter
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description (package private) int
cachedTokenCount()
void
end()
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
API).int
getTrailingPositions()
Return the number of trailing positions at the end of the graphprotected boolean
incrementBaseToken()
Move the root of the graph to the next token in the wrapped TokenStreamprotected boolean
incrementGraph()
Reset to the root token again, and move down the next route through the graphprotected boolean
incrementGraphToken()
Move to the next token in the current route through the graphprivate boolean
lastInStack(GraphTokenFilter.Token token)
private GraphTokenFilter.Token
newToken()
private GraphTokenFilter.Token
nextTokenInGraph(GraphTokenFilter.Token token)
private GraphTokenFilter.Token
nextTokenInStream(GraphTokenFilter.Token token)
private void
recycleToken(GraphTokenFilter.Token token)
void
reset()
This method is called by a consumer before it begins consumption usingTokenStream.incrementToken()
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Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, unwrap
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Methods inherited from class org.apache.lucene.analysis.TokenStream
incrementToken
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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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tokenPool
private final java.util.Deque<GraphTokenFilter.Token> tokenPool
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currentGraph
private final java.util.List<GraphTokenFilter.Token> currentGraph
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MAX_GRAPH_STACK_SIZE
public static final int MAX_GRAPH_STACK_SIZE
The maximum permitted number of routes through a graph- See Also:
- Constant Field Values
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MAX_TOKEN_CACHE_SIZE
public static final int MAX_TOKEN_CACHE_SIZE
The maximum permitted read-ahead in the token stream- See Also:
- Constant Field Values
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baseToken
private GraphTokenFilter.Token baseToken
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graphDepth
private int graphDepth
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graphPos
private int graphPos
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trailingPositions
private int trailingPositions
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finalOffsets
private int finalOffsets
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stackSize
private int stackSize
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cacheSize
private int cacheSize
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posIncAtt
private final PositionIncrementAttribute posIncAtt
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offsetAtt
private final OffsetAttribute offsetAtt
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Constructor Detail
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GraphTokenFilter
public GraphTokenFilter(TokenStream input)
Create a new GraphTokenFilter
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Method Detail
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incrementBaseToken
protected final boolean incrementBaseToken() throws java.io.IOException
Move the root of the graph to the next token in the wrapped TokenStream- Returns:
false
if the underlying stream is exhausted- Throws:
java.io.IOException
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incrementGraphToken
protected final boolean incrementGraphToken() throws java.io.IOException
Move to the next token in the current route through the graph- Returns:
false
if there are not more tokens in the current graph- Throws:
java.io.IOException
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incrementGraph
protected final boolean incrementGraph() throws java.io.IOException
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:
java.io.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
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end
public void end() throws java.io.IOException
Description copied from class:TokenFilter
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
API). 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:
end
in classTokenFilter
- Throws:
java.io.IOException
- If an I/O error occurs
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reset
public void reset() throws java.io.IOException
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:
java.io.IOException
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cachedTokenCount
int cachedTokenCount()
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newToken
private GraphTokenFilter.Token newToken()
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recycleToken
private void recycleToken(GraphTokenFilter.Token token)
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nextTokenInGraph
private GraphTokenFilter.Token nextTokenInGraph(GraphTokenFilter.Token token) throws java.io.IOException
- Throws:
java.io.IOException
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lastInStack
private boolean lastInStack(GraphTokenFilter.Token token) throws java.io.IOException
- Throws:
java.io.IOException
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nextTokenInStream
private GraphTokenFilter.Token nextTokenInStream(GraphTokenFilter.Token token) throws java.io.IOException
- Throws:
java.io.IOException
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