| Lucene Analyzers README file |
| |
| This project provides pre-compiled version of the Snowball stemmers |
| based on revision 502 of the Tartarus Snowball repository, |
| now located at https://github.com/snowballstem/snowball/tree/e103b5c257383ee94a96e7fc58cab3c567bf079b (GitHub), |
| together with classes integrating them with the Lucene search engine. |
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| A few changes has been made to the static Snowball code and compiled stemmers: |
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| * Class SnowballProgram is made abstract and contains new abstract method stem() to avoid reflection in Lucene filter class SnowballFilter. |
| * All use of StringBuffers has been refactored to StringBuilder for speed. |
| * Snowball BSD license header has been added to the Java classes to avoid having RAT adding new ASL headers. |
| * Uses Java 7 MethodHandles and fixes method visibility bug: http://article.gmane.org/gmane.comp.search.snowball/1139 |
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| If you want to add new stemmers, use the exact revision / Git commit above to generate the Java class, place it |
| in src/java/org/tartarus/snowball/ext, and finally execute "ant patch-snowball". The latter will change the APIs |
| of the generated class to make it compatible. Already patched classes are not modified. |
| The Arabic stemmer has been generated from https://github.com/snowballstem/snowball/blob/master/algorithms/arabic.sbl |
| using the latest version of snowball and patched manually. |
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| IMPORTANT NOTICE ON BACKWARDS COMPATIBILITY! |
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| An index created using the Snowball module in Lucene 2.3.2 and below |
| might not be compatible with the Snowball module in Lucene 2.4 or greater. |
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| For more information about this issue see: |
| https://issues.apache.org/jira/browse/LUCENE-1142 |
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| For more information on Snowball, see: |
| http://snowball.tartarus.org/ |
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