Package org.apache.lucene.util.automaton
Class LevenshteinAutomata
- java.lang.Object
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- org.apache.lucene.util.automaton.LevenshteinAutomata
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public class LevenshteinAutomata extends Object
Class to construct DFAs that match a word within some edit distance.Implements the algorithm described in: Schulz and Mihov: Fast String Correction with Levenshtein Automata
- WARNING: This API is experimental and might change in incompatible ways in the next release.
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Field Summary
Fields Modifier and Type Field Description static int
MAXIMUM_SUPPORTED_DISTANCE
Maximum edit distance this class can generate an automaton for.
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Constructor Summary
Constructors Constructor Description LevenshteinAutomata(int[] word, int alphaMax, boolean withTranspositions)
Expert: specify a custom maximum possible symbol (alphaMax); default is Character.MAX_CODE_POINT.LevenshteinAutomata(String input, boolean withTranspositions)
Create a new LevenshteinAutomata for some input String.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Automaton
toAutomaton(int n)
Compute a DFA that accepts all strings within an edit distance ofn
.Automaton
toAutomaton(int n, String prefix)
Compute a DFA that accepts all strings within an edit distance ofn
, matching the specified exact prefix.
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Field Detail
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MAXIMUM_SUPPORTED_DISTANCE
public static final int MAXIMUM_SUPPORTED_DISTANCE
Maximum edit distance this class can generate an automaton for.- See Also:
- Constant Field Values
- NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.
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Constructor Detail
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LevenshteinAutomata
public LevenshteinAutomata(String input, boolean withTranspositions)
Create a new LevenshteinAutomata for some input String. Optionally count transpositions as a primitive edit.
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LevenshteinAutomata
public LevenshteinAutomata(int[] word, int alphaMax, boolean withTranspositions)
Expert: specify a custom maximum possible symbol (alphaMax); default is Character.MAX_CODE_POINT.
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Method Detail
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toAutomaton
public Automaton toAutomaton(int n)
Compute a DFA that accepts all strings within an edit distance ofn
.All automata have the following properties:
- They are deterministic (DFA).
- There are no transitions to dead states.
- They are not minimal (some transitions could be combined).
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toAutomaton
public Automaton toAutomaton(int n, String prefix)
Compute a DFA that accepts all strings within an edit distance ofn
, matching the specified exact prefix.All automata have the following properties:
- They are deterministic (DFA).
- There are no transitions to dead states.
- They are not minimal (some transitions could be combined).
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