no.sesat.search.query.parser.alt
Interface Alternation

All Known Implementing Classes:

AbstractAlternation, FullnameAlternation, RotationAlternation

public interface Alternation

An Alternation is a query manipulation occurring on the query object after parsing has finished. Alernations are cpu expensive as Clauses are immutable and every change during the alternation results in a new Clause being constructed. A change in a clause deep within the query tree requires every parent in it's ancestry line back to the query's root clause being reconstructed. The value of alternation comes into play where the query parser cannot construct such a result, and doing the manipulation on-the-fly will likely occur multiple times during the request. It's typical that the alternations do not directly manipulate any clause but constructed an alternative clause to it and replaces the original clause with an XorClause that contains both the original and the new alternative. In these cases it is also typical that only one type of XorClause.Hint is used through that alternation process.

Version:

$Id: Alternation.java 7225 2009-04-09 00:32:20Z ssmiweve $

Nested Class Summary

static interface

Alternation.Context Context to work within.

Method Summary

Clause

alternate(Clause clause) Perform the alternation.

Method Detail

alternate

Clause alternate(Clause clause)

Perform the alternation.

Parameters:

clause -

Returns: