This discards the modification/stemming of words listed in the file protwords.txt. Any words in the protected word list will not be modified by any stemmer in Solr.

Arguments:

• protected: The path of the file that contains the protected word list, one per line

The following is the sample protwords.txt file:

removing
transforming

Example:

<fieldType name="text_en" class="solr.TextField" positionIncrementGap="100">
 <analyzer>
 <tokenizer class="solr.WhitespaceTokenizerFactory"/>
 <filter class="solr.KeywordMarkerFilterFactory" protected="protwords.txt" />
 <filter class="solr.KStemFilterFactory"/>
 </analyzer>
 </fieldType>

Input: remove removing removed transforming

Tokenizer to filter: remove, removing, removed, transforming

Output: remove, removing, remove, transforming

Here we can see that the words removing and transforming are not stemmed by KStemFilterFactory because they are mentioned in the file protwords.txt and protected by KeywordMarkerFilterFactory.