This class transforms the token stream as per the Porter stemming algorithm.
Note: the input to the stemming filter must already be in lower case, so you
will need to use LowerCaseFilter or LowerCaseTokenizer farther down the
Tokenizer chain in order for this to work properly!
The Porter Stemmer implements Porter Algorithm for normalization of English
words by stripping their extensions and is used to generalize the searches.
For example, the Porter algorithm maps both search and searching
(as well as searchnessing) to search such that a query for search will
also match documents that contains the word searching.
Note that the Porter algorithm is specific to the English language and may give
unpredictable results for other languages. Also, make sure to use the same
analyzer during the indexing and the searching.
You can find more information on the Porter algorithm at
A nice online demonstration of the Porter algorithm is available at