Package org.basex.util.ft

Class FTBitapSearch

java.lang.Object

org.basex.util.ft.FTBitapSearch

public final class FTBitapSearch
extends Object

Generalized search algorithm based on the Bitap string matching algorithm. The implementation is based on the implementation in Wikipedia, but uses BitSet for fast bit operation. This version works with a set of needles and each one of it can be matched in the haystack.

Author:

BaseX Team 2005-21, BSD License, Dimitar Popov

See Also:

• http://en.wikipedia.org/wiki/Bitap_algorithm

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	FTBitapSearch.TokenComparator	Token comparator.

Constructor Summary

Constructors

Constructor	Description
FTBitapSearch(FTIterator iter, FTTokens tokens, FTBitapSearch.TokenComparator cmp)	Constructor.

Method Summary

Modifier and Type	Method	Description
boolean	hasNext()	Is there one more match?
int	next()	Position in the haystack of the next match.

Methods inherited from class java.lang.Object

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

Constructor Details

FTBitapSearch

public FTBitapSearch(FTIterator iter,
 FTTokens tokens,
 FTBitapSearch.TokenComparator cmp)

Constructor.

Parameters:

iter - iterator over the set of elements being searched ("haystack")

tokens - a list of "needles" (a needle is an array of elements being searched for)

cmp - comparator for comparing two elements for equality

Method Details

hasNext

public boolean hasNext()
                throws QueryException

Is there one more match?

Returns:

true if yes

Throws:

QueryException - if an error occurs during search

next

public int next()
         throws QueryException

Position in the haystack of the next match.

Returns:

start position of the match; first position is 0

Throws:

QueryException - if an error occurs during search