Class WordDelimiterGraphFilter
- All Implemented Interfaces:
Closeable
,AutoCloseable
,Unwrappable<TokenStream>
PhraseQuery
can work correctly when this filter is used
in the search-time analyzer. Unlike the deprecated WordDelimiterFilter
, this token filter
produces a correct token graph as output. However, it cannot consume an input token graph
correctly. Processing is suppressed by KeywordAttribute.isKeyword()
=true.
Words are split into subwords with the following rules:
- split on intra-word delimiters (by default, all non alpha-numeric characters):
"Wi-Fi"
→"Wi", "Fi"
- split on case transitions:
"PowerShot"
→"Power", "Shot"
- split on letter-number transitions:
"SD500"
→"SD", "500"
- leading and trailing intra-word delimiters on each subword are ignored:
"//hello---there, 'dude'"
→"hello", "there", "dude"
- trailing "'s" are removed for each subword:
"O'Neil's"
→"O", "Neil"
- Note: this step isn't performed in a separate filter because of possible subword combinations.
- If no CATENATE option is set, then no subword combinations are generated:
"PowerShot"
→0:"Power", 1:"Shot"
(0 and 1 are the token positions) - CATENATE_WORDS means that in addition to the subwords, maximum runs of non-numeric subwords
are catenated and produced at the same position of the last subword in the run:
"PowerShot"
→0:"Power", 1:"Shot" 1:"PowerShot"
"A's+B's&C's"
>0:"A", 1:"B", 2:"C", 2:"ABC"
"Super-Duper-XL500-42-AutoCoder!"
→0:"Super", 1:"Duper", 2:"XL", 2:"SuperDuperXL", 3:"500" 4:"42", 5:"Auto", 6:"Coder", 6:"AutoCoder"
- CATENATE_NUMBERS works like CATENATE_WORDS, but for adjacent digit sequences.
- CATENATE_ALL smushes together all the token parts without distinguishing numbers and words.
WordDelimiterGraphFilter
is to help match words with different subword
delimiters. For example, if the source text contained "wi-fi" one may want "wifi" "WiFi" "wi-fi"
"wi+fi" queries to all match. One way of doing so is to specify CATENATE options in the analyzer
used for indexing, and not in the analyzer used for querying. Given that the current StandardTokenizer
immediately removes many intra-word delimiters, it is recommended that this
filter be used after a tokenizer that does not do this (such as WhitespaceTokenizer
).-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate class
(package private) final class
A WDF concatenated 'run'Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
AttributeSource.State
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate int
private boolean
private final boolean
private int
private int[]
private int
private char[][]
static final int
Causes all subword parts to be catenated:static final int
Causes maximum runs of number parts to be catenated:static final int
Causes maximum runs of word parts to be catenated:private final WordDelimiterGraphFilter.WordDelimiterConcatenation
private final WordDelimiterGraphFilter.WordDelimiterConcatenation
private final int
static final int
Causes number subwords to be generated:static final int
Causes parts of words to be generated:static final int
Suppresses processing terms withKeywordAttribute.isKeyword()
=true.private final WordDelimiterIterator
private final KeywordAttribute
private int
private int
private final OffsetAttribute
private final PositionIncrementAttribute
private final PositionLengthAttribute
static final int
Causes original words are preserved and added to the subword list (Defaults to false)(package private) final CharArraySet
If not null is the set of tokens to protect from being delimitedprivate int
private int
private AttributeSource.State
private char[]
private int
(package private) final WordDelimiterGraphFilter.PositionSorter
static final int
Causes lowercase -> uppercase transition to start a new subword.static final int
If not set, causes numeric changes to be ignored (subwords will only be generated given SUBWORD_DELIM tokens).static final int
Causes trailing "'s" to be removed for each subwordprivate final CharTermAttribute
private int
Fields inherited from class org.apache.lucene.analysis.TokenFilter
input
Fields inherited from class org.apache.lucene.analysis.TokenStream
DEFAULT_TOKEN_ATTRIBUTE_FACTORY
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Constructor Summary
ConstructorsConstructorDescriptionWordDelimiterGraphFilter
(TokenStream in, boolean adjustInternalOffsets, byte[] charTypeTable, int configurationFlags, CharArraySet protWords) Creates a new WordDelimiterGraphFilterWordDelimiterGraphFilter
(TokenStream in, int configurationFlags, CharArraySet protWords) Creates a new WordDelimiterGraphFilter usingWordDelimiterIterator.DEFAULT_WORD_DELIM_TABLE
as its charTypeTable -
Method Summary
Modifier and TypeMethodDescription(package private) void
buffer
(char[] termPart, int startPos, int endPos, int startPart, int endPart) a null termPart means it's a simple slice of the original term(package private) void
buffer
(int startPos, int endPos, int startPart, int endPart) startPos, endPos -> graph start/end position startPart, endPart -> slice of the original term for this partprivate void
Iterates all words parts and concatenations, buffering up the term parts we should return.private void
concatenate
(WordDelimiterGraphFilter.WordDelimiterConcatenation concatenation) Concatenates the saved buffer to the given WordDelimiterConcatenationstatic String
flagsToString
(int flags) Returns string representation of configuration flagsprivate void
Flushes the given WordDelimiterConcatenation by either writing its concat and then clearing, or just clearing.private boolean
has
(int flag) Determines whether the given flag is setboolean
Consumers (i.e.,IndexWriter
) use this method to advance the stream to the next token.void
reset()
This method is called by a consumer before it begins consumption usingTokenStream.incrementToken()
.private void
Saves the existing attribute statesprivate boolean
shouldConcatenate
(int wordType) Determines whether to concatenate a word or number if the current word is the given typeprivate boolean
shouldGenerateParts
(int wordType) Determines whether a word/number part should be generated for a word of the given typetoString()
Returns a string consisting of the class's simple name, the hex representation of the identity hash code, and the current reflection of all attributes.Methods inherited from class org.apache.lucene.analysis.TokenFilter
close, end, unwrap
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
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Field Details
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GENERATE_WORD_PARTS
public static final int GENERATE_WORD_PARTSCauses parts of words to be generated:"PowerShot" => "Power" "Shot"
- See Also:
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GENERATE_NUMBER_PARTS
public static final int GENERATE_NUMBER_PARTSCauses number subwords to be generated:"500-42" => "500" "42"
- See Also:
-
CATENATE_WORDS
public static final int CATENATE_WORDSCauses maximum runs of word parts to be catenated:"wi-fi" => "wifi"
- See Also:
-
CATENATE_NUMBERS
public static final int CATENATE_NUMBERSCauses maximum runs of number parts to be catenated:"500-42" => "50042"
- See Also:
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CATENATE_ALL
public static final int CATENATE_ALLCauses all subword parts to be catenated:"wi-fi-4000" => "wifi4000"
- See Also:
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PRESERVE_ORIGINAL
public static final int PRESERVE_ORIGINALCauses original words are preserved and added to the subword list (Defaults to false)"500-42" => "500" "42" "500-42"
- See Also:
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SPLIT_ON_CASE_CHANGE
public static final int SPLIT_ON_CASE_CHANGECauses lowercase -> uppercase transition to start a new subword.- See Also:
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SPLIT_ON_NUMERICS
public static final int SPLIT_ON_NUMERICSIf not set, causes numeric changes to be ignored (subwords will only be generated given SUBWORD_DELIM tokens).- See Also:
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STEM_ENGLISH_POSSESSIVE
public static final int STEM_ENGLISH_POSSESSIVECauses trailing "'s" to be removed for each subword"O'Neil's" => "O", "Neil"
- See Also:
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IGNORE_KEYWORDS
public static final int IGNORE_KEYWORDSSuppresses processing terms withKeywordAttribute.isKeyword()
=true.- See Also:
-
protWords
If not null is the set of tokens to protect from being delimited -
flags
private final int flags -
bufferedParts
private int[] bufferedParts -
bufferedLen
private int bufferedLen -
bufferedPos
private int bufferedPos -
bufferedTermParts
private char[][] bufferedTermParts -
termAttribute
-
keywordAttribute
-
offsetAttribute
-
posIncAttribute
-
posLenAttribute
-
iterator
-
concat
-
adjustInternalOffsets
private final boolean adjustInternalOffsets -
lastConcatCount
private int lastConcatCount -
concatAll
-
accumPosInc
private int accumPosInc -
savedTermBuffer
private char[] savedTermBuffer -
savedTermLength
private int savedTermLength -
savedStartOffset
private int savedStartOffset -
savedEndOffset
private int savedEndOffset -
savedState
-
lastStartOffset
private int lastStartOffset -
adjustingOffsets
private boolean adjustingOffsets -
wordPos
private int wordPos -
sorter
-
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Constructor Details
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WordDelimiterGraphFilter
public WordDelimiterGraphFilter(TokenStream in, boolean adjustInternalOffsets, byte[] charTypeTable, int configurationFlags, CharArraySet protWords) Creates a new WordDelimiterGraphFilter- Parameters:
in
- TokenStream to be filteredadjustInternalOffsets
- if the offsets of partial terms should be adjustedcharTypeTable
- table containing character typesconfigurationFlags
- Flags configuring the filterprotWords
- If not null is the set of tokens to protect from being delimited
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WordDelimiterGraphFilter
Creates a new WordDelimiterGraphFilter usingWordDelimiterIterator.DEFAULT_WORD_DELIM_TABLE
as its charTypeTable- Parameters:
in
- TokenStream to be filteredconfigurationFlags
- Flags configuring the filterprotWords
- If not null is the set of tokens to protect from being delimited
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Method Details
-
bufferWordParts
Iterates all words parts and concatenations, buffering up the term parts we should return.- Throws:
IOException
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incrementToken
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:
IOException
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reset
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:
IOException
-
buffer
void buffer(int startPos, int endPos, int startPart, int endPart) startPos, endPos -> graph start/end position startPart, endPart -> slice of the original term for this part -
buffer
void buffer(char[] termPart, int startPos, int endPos, int startPart, int endPart) a null termPart means it's a simple slice of the original term -
saveState
private void saveState()Saves the existing attribute states -
flushConcatenation
Flushes the given WordDelimiterConcatenation by either writing its concat and then clearing, or just clearing.- Parameters:
concat
- WordDelimiterConcatenation that will be flushed
-
shouldConcatenate
private boolean shouldConcatenate(int wordType) Determines whether to concatenate a word or number if the current word is the given type- Parameters:
wordType
- Type of the current word used to determine if it should be concatenated- Returns:
true
if concatenation should occur,false
otherwise
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shouldGenerateParts
private boolean shouldGenerateParts(int wordType) Determines whether a word/number part should be generated for a word of the given type- Parameters:
wordType
- Type of the word used to determine if a word/number part should be generated- Returns:
true
if a word/number part should be generated,false
otherwise
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concatenate
Concatenates the saved buffer to the given WordDelimiterConcatenation- Parameters:
concatenation
- WordDelimiterConcatenation to concatenate the buffer to
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has
private boolean has(int flag) Determines whether the given flag is set- Parameters:
flag
- Flag to see if set- Returns:
true
if flag is set
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flagsToString
Returns string representation of configuration flags -
toString
Description copied from class:AttributeSource
Returns a string consisting of the class's simple name, the hex representation of the identity hash code, and the current reflection of all attributes.- Overrides:
toString
in classAttributeSource
- See Also:
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