org.apache.lucene.search
Class FuzzyTermEnum

java.lang.Object
  org.apache.lucene.index.TermEnum
      org.apache.lucene.search.FilteredTermEnum
          org.apache.lucene.search.FuzzyTermEnum

All Implemented Interfaces:

Closeable

public final class FuzzyTermEnum
extends FilteredTermEnum

Subclass of FilteredTermEnum for enumerating all terms that are similar to the specified filter term.

Term enumerations are always ordered by Term.compareTo(). Each term in the enumeration is greater than all that precede it.

Field Summary

Fields inherited from class org.apache.lucene.search.FilteredTermEnum

actualEnum, currentTerm

Constructor Summary

FuzzyTermEnum(IndexReader reader, Term term)
Creates a FuzzyTermEnum with an empty prefix and a minSimilarity of 0.5f.

FuzzyTermEnum(IndexReader reader, Term term, float minSimilarity)
Creates a FuzzyTermEnum with an empty prefix.

FuzzyTermEnum(IndexReader reader, Term term, float minSimilarity, int prefixLength)
Constructor for enumeration of all terms from specified reader which share a prefix of length prefixLength with term and which have a fuzzy similarity > minSimilarity.

Method Summary

void	close() Closes the enumeration to further activity, freeing resources.
float	difference() Equality measure on the term
boolean	endEnum() Indicates the end of the enumeration has been reached
protected boolean	termCompare(Term term) The termCompare method in FuzzyTermEnum uses Levenshtein distance to calculate the distance between the given term and the comparing term.

Methods inherited from class org.apache.lucene.search.FilteredTermEnum

docFreq, next, setEnum, term

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FuzzyTermEnum

public FuzzyTermEnum(IndexReader reader,
                     Term term)
              throws IOException

Creates a FuzzyTermEnum with an empty prefix and a minSimilarity of 0.5f.

After calling the constructor the enumeration is already pointing to the first valid term if such a term exists.

Parameters:

reader -

term -

Throws:

IOException

See Also:

FuzzyTermEnum(IndexReader, Term, float, int)

FuzzyTermEnum

public FuzzyTermEnum(IndexReader reader,
                     Term term,
                     float minSimilarity)
              throws IOException

Creates a FuzzyTermEnum with an empty prefix.

After calling the constructor the enumeration is already pointing to the first valid term if such a term exists.

Parameters:

reader -

term -

minSimilarity -

Throws:

IOException

See Also:

FuzzyTermEnum(IndexReader, Term, float, int)

FuzzyTermEnum

public FuzzyTermEnum(IndexReader reader,
                     Term term,
                     float minSimilarity,
                     int prefixLength)
              throws IOException

Constructor for enumeration of all terms from specified reader which share a prefix of length prefixLength with term and which have a fuzzy similarity > minSimilarity.

After calling the constructor the enumeration is already pointing to the first valid term if such a term exists.

Parameters:

reader - Delivers terms.

term - Pattern term.

minSimilarity - Minimum required similarity for terms from the reader. Default value is 0.5f.

prefixLength - Length of required common prefix. Default value is 0.

Throws:

IOException

Method Detail

termCompare

protected final boolean termCompare(Term term)

The termCompare method in FuzzyTermEnum uses Levenshtein distance to calculate the distance between the given term and the comparing term.

Specified by:

termCompare in class FilteredTermEnum

difference

public final float difference()

Equality measure on the term

Specified by:

difference in class FilteredTermEnum

endEnum

public final boolean endEnum()

Indicates the end of the enumeration has been reached

Specified by:

endEnum in class FilteredTermEnum

close

public void close()
           throws IOException

Closes the enumeration to further activity, freeing resources.

Specified by:

close in interface Closeable

Overrides:

close in class FilteredTermEnum

Throws:

IOException