public final class XFuzzySuggester extends XAnalyzingSuggester
AnalyzingSuggester. The similarity measurement is based on the Damerau-Levenshtein (optimal string alignment) algorithm, though you can explicitly choose classic Levenshtein by passing
false for the
transpositions parameter.
At most, this query will match terms up to 2 edits. Higher distances are not supported. Note that the fuzzy distance is measured in "byte space" on the bytes returned by the TokenStream's TermToBytesRefAttribute, usually UTF8. By default the analyzed bytes must be at least 3 DEFAULT_MIN_FUZZY_LENGTH bytes before any edits are considered. Furthermore, the first 1 DEFAULT_NON_FUZZY_PREFIX byte is not allowed to be edited. We allow up to 1 (@link #DEFAULT_MAX_EDITS} edit. If unicodeAware parameter in the constructor is set to true, maxEdits, minFuzzyLength, transpositions and nonFuzzyPrefix are measured in Unicode code points (actual letters) instead of bytes.*
NOTE: This suggester does not boost suggestions that required no edits over suggestions that did require edits. This is a known limitation.
Note: complex query analyzers can have a significant impact on the lookup performance. It's recommended to not use analyzers that drop or inject terms like synonyms to keep the complexity of the prefix intersection low for good lookup performance. At index time, complex analyzers can safely be used.
XAnalyzingSuggester.XBuilder | Modifier and Type | Field and Description |
|---|---|
static int |
DEFAULT_MAX_EDITS
The default maximum number of edits for fuzzy suggestions.
|
static int |
DEFAULT_MIN_FUZZY_LENGTH
The default minimum length of the key passed to
XAnalyzingSuggester before any edits are allowed.
|
static int |
DEFAULT_NON_FUZZY_PREFIX
The default prefix length where edits are not allowed.
|
static boolean |
DEFAULT_TRANSPOSITIONS
The default transposition value passed to
LevenshteinAutomata
|
static boolean |
DEFAULT_UNICODE_AWARE
Measure maxEdits, minFuzzyLength, transpositions and nonFuzzyPrefix parameters in Unicode code points (actual letters) instead of bytes.
|
END_BYTE, EXACT_FIRST, HOLE_CHARACTER, PAYLOAD_SEP, PRESERVE_SEP, SEP_LABEL| Constructor and Description |
|---|
XFuzzySuggester(org
Creates a
FuzzySuggester instance initialized with default values.
|
XFuzzySuggester(org
Creates a
FuzzySuggester instance with an index & a query analyzer initialized with default values.
|
XFuzzySuggester(org
Creates a
FuzzySuggester instance.
|
| Modifier and Type | Method and Description |
|---|---|
protected org |
convertAutomaton(org
|
protected List |
getFullPrefixPaths(List
Returns all completion paths to initialize the search.
|
org |
getTokenStreamToAutomaton()
|
build, decodeWeight, encodeWeight, get, getCount, load, load, lookup, ramBytesUsed, store, store, toFiniteStrings, toFiniteStringspublic static final boolean DEFAULT_UNICODE_AWARE
public static final int DEFAULT_MIN_FUZZY_LENGTH
XAnalyzingSuggester.lookup(java.lang.CharSequence, java.util.Set<org.apache.lucene.util.BytesRef>, boolean, int) before any edits are allowed.
public static final int DEFAULT_NON_FUZZY_PREFIX
public static final int DEFAULT_MAX_EDITS
public static final boolean DEFAULT_TRANSPOSITIONS
LevenshteinAutomata
public XFuzzySuggester(org.apache .lucene .analysis .Analyzer analyzer)
FuzzySuggester instance initialized with default values.
analyzer - the analyzer used for this suggester
public XFuzzySuggester(org.apache .lucene .analysis .Analyzer indexAnalyzer, org .apache .lucene .analysis .Analyzer queryAnalyzer)
FuzzySuggester instance with an index & a query analyzer initialized with default values.
indexAnalyzer - Analyzer that will be used for analyzing suggestions while building the index.
queryAnalyzer - Analyzer that will be used for analyzing query text during lookup
public XFuzzySuggester(org.apache .lucene .analysis .Analyzer indexAnalyzer, org .apache .lucene .util .automaton .Automaton queryPrefix, org .apache .lucene .analysis .Analyzer queryAnalyzer, int options, int maxSurfaceFormsPerAnalyzedForm, int maxGraphExpansions, int maxEdits, boolean transpositions, int nonFuzzyPrefix, int minFuzzyLength, boolean unicodeAware, org .apache .lucene .util .fst .FST <org .apache .lucene .util .fst .PairOutputs .Pair <Long ,org .apache .lucene .util .BytesRef >> fst, boolean hasPayloads, int maxAnalyzedPathsForOneInput, int sepLabel, int payloadSep, int endByte, int holeCharacter)
FuzzySuggester instance.
indexAnalyzer - Analyzer that will be used for analyzing suggestions while building the index.
queryAnalyzer - Analyzer that will be used for analyzing query text during lookup
options - see
XAnalyzingSuggester.EXACT_FIRST ,
XAnalyzingSuggester.PRESERVE_SEP
maxSurfaceFormsPerAnalyzedForm - Maximum number of surface forms to keep for a single analyzed form. When there are too many surface forms we discard the lowest weighted ones.
maxGraphExpansions - Maximum number of graph paths to expand from the analyzed form. Set this to -1 for no limit.
maxEdits - must be >= 0 and <=
LevenshteinAutomata.MAXIMUM_SUPPORTED_DISTANCE .
transpositions -
true if transpositions should be treated as a primitive edit operation. If this is false, comparisons will implement the classic Levenshtein algorithm.
nonFuzzyPrefix - length of common (non-fuzzy) prefix (see default
DEFAULT_NON_FUZZY_PREFIX
minFuzzyLength - minimum length of lookup key before any edits are allowed (see default
DEFAULT_MIN_FUZZY_LENGTH)
sepLabel - separation label
payloadSep - payload separator byte
endByte - end byte marker byte
protected List<org .apache .lucene .search .suggest .analyzing .FSTUtil .Path <org .apache .lucene .util .fst .PairOutputs .Pair <Long ,org .apache .lucene .util .BytesRef >>> getFullPrefixPaths(List <org .apache .lucene .search .suggest .analyzing .FSTUtil .Path <org .apache .lucene .util .fst .PairOutputs .Pair <Long ,org .apache .lucene .util .BytesRef >>> prefixPaths, org .apache .lucene .util .automaton .Automaton lookupAutomaton, org .apache .lucene .util .fst .FST <org .apache .lucene .util .fst .PairOutputs .Pair <Long ,org .apache .lucene .util .BytesRef >> fst) throws IOException
XAnalyzingSuggester
getFullPrefixPaths in class
XAnalyzingSuggester
IOException
protected org.apache .lucene .util .automaton .Automaton convertAutomaton(org .apache .lucene .util .automaton .Automaton a)
public org.apache .lucene .analysis .TokenStreamToAutomaton getTokenStreamToAutomaton()