Class ConcatenateGraphFilter
- 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.miscellaneous.ConcatenateGraphFilter
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
public final class ConcatenateGraphFilter extends TokenStream
Concatenates/Joins every incoming token with a separator into one output token for every path through the token stream (which is a graph). In simple cases this yields one token, but in the presence of any tokens with a zero positionIncrmeent (e.g. synonyms) it will be more. This filter uses the token bytes, position increment, and position length of the incoming stream. Other attributes are not used or manipulated.
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Nested Class Summary
Nested Classes Modifier and Type Class Description static interface
ConcatenateGraphFilter.BytesRefBuilderTermAttribute
Attribute providing access to the term builder and UTF-16 conversionstatic class
ConcatenateGraphFilter.BytesRefBuilderTermAttributeImpl
Implementation ofConcatenateGraphFilter.BytesRefBuilderTermAttribute
private static class
ConcatenateGraphFilter.EscapingTokenStreamToAutomaton
Just escapes theSEP_LABEL
byte with an extra.-
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 ConcatenateGraphFilter.BytesRefBuilderTermAttribute
bytesAtt
private CharTermAttribute
charTermAttribute
static int
DEFAULT_MAX_GRAPH_EXPANSIONS
static boolean
DEFAULT_PRESERVE_POSITION_INCREMENTS
static boolean
DEFAULT_PRESERVE_SEP
static java.lang.Character
DEFAULT_TOKEN_SEPARATOR
private int
endOffset
private LimitedFiniteStringsIterator
finiteStrings
private TokenStream
inputTokenStream
private int
maxGraphExpansions
private OffsetAttribute
offsetAtt
private PositionIncrementAttribute
posIncrAtt
private boolean
preservePositionIncrements
static int
SEP_LABEL
Represents the default separator between tokens.private java.lang.Character
tokenSeparator
private boolean
wasReset
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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 ConcatenateGraphFilter(TokenStream inputTokenStream)
Creates a token stream to convertinput
to a token stream of accepted strings by its token stream graph.ConcatenateGraphFilter(TokenStream inputTokenStream, boolean preserveSep, boolean preservePositionIncrements, int maxGraphExpansions)
ConcatenateGraphFilter(TokenStream inputTokenStream, java.lang.Character tokenSeparator, boolean preservePositionIncrements, int maxGraphExpansions)
Creates a token stream to convertinput
to a token stream of accepted strings by its token stream graph.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
close()
Releases resources associated with this stream.void
end()
This method is called by the consumer after the last token has been consumed, afterTokenStream.incrementToken()
returnedfalse
(using the newTokenStream
API).boolean
incrementToken()
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token.private static Automaton
replaceSep(Automaton a, java.lang.Character tokenSeparator)
void
reset()
This method is called by a consumer before it begins consumption usingTokenStream.incrementToken()
.Automaton
toAutomaton()
Converts the tokenStream to an automaton, treating the transition labels as utf-8.Automaton
toAutomaton(boolean unicodeAware)
Converts the tokenStream to an automaton.-
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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SEP_LABEL
public static final int SEP_LABEL
Represents the default separator between tokens.- See Also:
- Constant Field Values
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DEFAULT_MAX_GRAPH_EXPANSIONS
public static final int DEFAULT_MAX_GRAPH_EXPANSIONS
- See Also:
- Constant Field Values
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DEFAULT_TOKEN_SEPARATOR
public static final java.lang.Character DEFAULT_TOKEN_SEPARATOR
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DEFAULT_PRESERVE_SEP
public static final boolean DEFAULT_PRESERVE_SEP
- See Also:
- Constant Field Values
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DEFAULT_PRESERVE_POSITION_INCREMENTS
public static final boolean DEFAULT_PRESERVE_POSITION_INCREMENTS
- See Also:
- Constant Field Values
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bytesAtt
private final ConcatenateGraphFilter.BytesRefBuilderTermAttribute bytesAtt
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posIncrAtt
private final PositionIncrementAttribute posIncrAtt
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offsetAtt
private final OffsetAttribute offsetAtt
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inputTokenStream
private final TokenStream inputTokenStream
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tokenSeparator
private final java.lang.Character tokenSeparator
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preservePositionIncrements
private final boolean preservePositionIncrements
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maxGraphExpansions
private final int maxGraphExpansions
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finiteStrings
private LimitedFiniteStringsIterator finiteStrings
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charTermAttribute
private CharTermAttribute charTermAttribute
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wasReset
private boolean wasReset
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endOffset
private int endOffset
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Constructor Detail
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ConcatenateGraphFilter
public ConcatenateGraphFilter(TokenStream inputTokenStream)
Creates a token stream to convertinput
to a token stream of accepted strings by its token stream graph.This constructor uses the default settings of the constants in this class.
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ConcatenateGraphFilter
public ConcatenateGraphFilter(TokenStream inputTokenStream, java.lang.Character tokenSeparator, boolean preservePositionIncrements, int maxGraphExpansions)
Creates a token stream to convertinput
to a token stream of accepted strings by its token stream graph.- Parameters:
inputTokenStream
- The input/incoming TokenStreamtokenSeparator
- Separator to use for concatenation. Can be null, in this case tokens will be concatenated without any separators.preservePositionIncrements
- Whether to add an empty token for missing positions. The effect is a consecutiveSEP_LABEL
. When false, it's as if there were no missing positions (we pretend the surrounding tokens were adjacent).maxGraphExpansions
- If the tokenStream graph has more than this many possible paths through, then we'll throwTooComplexToDeterminizeException
to preserve the stability and memory of the machine.- Throws:
TooComplexToDeterminizeException
- if the tokenStream graph has more thanmaxGraphExpansions
expansions
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ConcatenateGraphFilter
public ConcatenateGraphFilter(TokenStream inputTokenStream, boolean preserveSep, boolean preservePositionIncrements, int maxGraphExpansions)
CallsConcatenateGraphFilter(org.apache.lucene.analysis.TokenStream, java.lang.Character, boolean, int)
- Parameters:
preserveSep
- WhetherSEP_LABEL
should separate the input tokens in the concatenated token
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Method Detail
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reset
public void reset() throws java.io.IOException
Description copied from class:TokenStream
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).- Overrides:
reset
in classTokenStream
- Throws:
java.io.IOException
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incrementToken
public boolean incrementToken() throws java.io.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:
java.io.IOException
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end
public void end() throws java.io.IOException
Description copied from class:TokenStream
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()
.- Overrides:
end
in classTokenStream
- Throws:
java.io.IOException
- If an I/O error occurs
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close
public void close() throws java.io.IOException
Description copied from class:TokenStream
Releases resources associated with this stream.If you override this method, always call
super.close()
, otherwise some internal state will not be correctly reset (e.g.,Tokenizer
will throwIllegalStateException
on reuse).- Specified by:
close
in interfacejava.lang.AutoCloseable
- Specified by:
close
in interfacejava.io.Closeable
- Overrides:
close
in classTokenStream
- Throws:
java.io.IOException
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toAutomaton
public Automaton toAutomaton() throws java.io.IOException
Converts the tokenStream to an automaton, treating the transition labels as utf-8. Does *not* close it.- Throws:
java.io.IOException
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toAutomaton
public Automaton toAutomaton(boolean unicodeAware) throws java.io.IOException
Converts the tokenStream to an automaton. Does *not* close it.- Throws:
java.io.IOException
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