public class SynonymMap
extends java.lang.Object
There holds: If B is a synonym for A (A -> B) then A is also a synonym for B (B -> A). There does not necessarily hold: A -> B, B -> C then A -> C.
Loading typically takes some 1.5 secs, so should be done only once per
(server) program execution, using a singleton pattern. Once loaded, a
synonym lookup via getSynonyms(String)
takes constant time O(1).
A loaded default synonym map consumes about 10 MB main memory.
An instance is immutable, hence thread-safe.
This implementation borrows some ideas from the Lucene Syns2Index demo that Dave Spencer originally contributed to Lucene. Dave's approach involved a persistent Lucene index which is suitable for occasional lookups or very large synonym tables, but considered unsuitable for high-frequency lookups of medium size synonym tables.
Example Usage:
String[] words = new String[] { "hard", "woods", "forest", "wolfish", "xxxx"}; SynonymMap map = new SynonymMap(new FileInputStream("samples/fulltext/wn_s.pl")); for (int i = 0; i < words.length; i++) { String[] synonyms = map.getSynonyms(words[i]); System.out.println(words[i] + ":" + java.util.Arrays.asList(synonyms).toString()); } Example output: hard:[arduous, backbreaking, difficult, fermented, firmly, grueling, gruelling, heavily, heavy, intemperately, knockout, laborious, punishing, severe, severely, strong, toilsome, tough] woods:[forest, wood] forest:[afforest, timber, timberland, wood, woodland, woods] wolfish:[edacious, esurient, rapacious, ravening, ravenous, voracious, wolflike] xxxx:[]
Constructor and Description |
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SynonymMap(java.io.InputStream input)
Constructs an instance, loading WordNet synonym data from the given input
stream.
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Modifier and Type | Method and Description |
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protected java.lang.String |
analyze(java.lang.String word)
Analyzes/transforms the given word on input stream loading.
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java.lang.String[] |
getSynonyms(java.lang.String word)
Returns the synonym set for the given word, sorted ascending.
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java.lang.String |
toString()
Returns a String representation of the index data for debugging purposes.
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public SynonymMap(java.io.InputStream input) throws java.io.IOException
input
- the stream to read from (null indicates an empty synonym map)java.io.IOException
- if an error occured while reading the stream.public java.lang.String[] getSynonyms(java.lang.String word)
word
- the word to lookup (must be in lowercase).Character.isLetter()
.public java.lang.String toString()
toString
in class java.lang.Object
protected java.lang.String analyze(java.lang.String word)
word
- the word to analyzeCopyright © 2000-2018 Apache Software Foundation. All Rights Reserved.