Package org.apache.lucene.analysis.miscellaneous

Class ConcatenateGraphFilter

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.miscellaneous.ConcatenateGraphFilter

All Implemented Interfaces:

Closeable, 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.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	ConcatenateGraphFilter.BytesRefBuilderTermAttribute	Attribute providing access to the term builder and UTF-16 conversion
static class	ConcatenateGraphFilter.BytesRefBuilderTermAttributeImpl	Implementation of ConcatenateGraphFilter.BytesRefBuilderTermAttribute

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

AttributeSource.State

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_MAX_GRAPH_EXPANSIONS
static boolean	DEFAULT_PRESERVE_POSITION_INCREMENTS
static boolean	DEFAULT_PRESERVE_SEP
static Character	DEFAULT_TOKEN_SEPARATOR
static int	SEP_LABEL	Represents the default separator between tokens.

Fields inherited from class org.apache.lucene.analysis.TokenStream

DEFAULT_TOKEN_ATTRIBUTE_FACTORY

Constructor Summary

Constructors

Constructor	Description
ConcatenateGraphFilter(TokenStream inputTokenStream)	Creates a token stream to convert input to a token stream of accepted strings by its token stream graph.
ConcatenateGraphFilter(TokenStream inputTokenStream, boolean preserveSep, boolean preservePositionIncrements, int maxGraphExpansions)	Calls ConcatenateGraphFilter(org.apache.lucene.analysis.TokenStream, java.lang.Character, boolean, int)
ConcatenateGraphFilter(TokenStream inputTokenStream, Character tokenSeparator, boolean preservePositionIncrements, int maxGraphExpansions)	Creates a token stream to convert input to a token stream of accepted strings by its token stream graph.

Method Summary

Modifier and Type	Method	Description
void	close()
void	end()
boolean	incrementToken()
void	reset()
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

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

SEP_LABEL

public static final int SEP_LABEL

Represents the default separator between tokens.

See Also:

Constant Field Values

DEFAULT_MAX_GRAPH_EXPANSIONS

public static final int DEFAULT_MAX_GRAPH_EXPANSIONS

See Also:

Constant Field Values

DEFAULT_TOKEN_SEPARATOR

public static final Character DEFAULT_TOKEN_SEPARATOR

DEFAULT_PRESERVE_SEP

public static final boolean DEFAULT_PRESERVE_SEP

See Also:

Constant Field Values

DEFAULT_PRESERVE_POSITION_INCREMENTS

public static final boolean DEFAULT_PRESERVE_POSITION_INCREMENTS

See Also:

Constant Field Values

Constructor Detail

ConcatenateGraphFilter

public ConcatenateGraphFilter(TokenStream inputTokenStream)

Creates a token stream to convert input to a token stream of accepted strings by its token stream graph.

This constructor uses the default settings of the constants in this class.

ConcatenateGraphFilter

public ConcatenateGraphFilter(TokenStream inputTokenStream,
                              Character tokenSeparator,
                              boolean preservePositionIncrements,
                              int maxGraphExpansions)

Creates a token stream to convert input to a token stream of accepted strings by its token stream graph.

Parameters:

inputTokenStream - The input/incoming TokenStream

tokenSeparator - 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 consecutive SEP_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 throw TooComplexToDeterminizeException to preserve the stability and memory of the machine.

Throws:

TooComplexToDeterminizeException - if the tokenStream graph has more than maxGraphExpansions expansions

ConcatenateGraphFilter

public ConcatenateGraphFilter(TokenStream inputTokenStream,
                              boolean preserveSep,
                              boolean preservePositionIncrements,
                              int maxGraphExpansions)

Calls ConcatenateGraphFilter(org.apache.lucene.analysis.TokenStream, java.lang.Character, boolean, int)

Parameters:

preserveSep - Whether SEP_LABEL should separate the input tokens in the concatenated token

Method Detail

reset

public void reset()
           throws IOException

Overrides:

reset in class TokenStream

Throws:

IOException

incrementToken

public boolean incrementToken()
                       throws IOException

Specified by:

incrementToken in class TokenStream

Throws:

IOException

end

public void end()
         throws IOException

Overrides:

end in class TokenStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class TokenStream

Throws:

IOException

toAutomaton

public Automaton toAutomaton()
                      throws IOException

Converts the tokenStream to an automaton, treating the transition labels as utf-8. Does *not* close it.

Throws:

IOException

toAutomaton

public Automaton toAutomaton(boolean unicodeAware)
                      throws IOException

Converts the tokenStream to an automaton. Does *not* close it.

Throws:

IOException