@Override
    public Set<String> getEntityTypes() {
        return entityTypes;
    }
This class offers an implementation of {@link NERecogniser} based on
Regular Expressions.
<p>
The default configuration file {@value NER_REGEX_FILE} is used when no
argument constructor is used to instantiate this class. The regex file is
loaded via {@link Class#getResourceAsStream(String)}, so the file should be
placed in the same package path as of this class.
</p>
The format of regex configuration as follows:
<pre>
ENTITY_TYPE1=REGEX1
ENTITY_TYPE2=REGEX2
</pre>

<i>For example, to extract week day from text:</i>
<pre>WEEK_DAY=(?i)((sun)|(mon)|(tues)|(thurs)|(fri)|((sat)(ur)?))(day)?
</pre>

@since Nov. 7, 2015
tika-parsers/tika-parsers-ml/tika-parser-nlp-module/src/main/java/org/apache/tika/parser/ner/regex/RegexNERecogniser.java