private void setupAutomatonFile(String phraseAutomatonFile) {
        if (phraseAutomatonFile == null || phraseAutomatonFile.trim().isEmpty()) {
            //no file, just use dummy matcher
            phraseMatcher = PhraseMatcher.getNullMatcher();
        } else {
            //use real matcher
            phraseMatcher = new PhraseMatcher(phraseAutomatonFile);
        }
    }
Creates a nonphrasing searcher

@param  phraseAutomatonFile the file containing phrases which should be removed
@throws IllegalStateException if the automata component is unavailable
        in the current environment
@throws IllegalArgumentException if the file is not found
container-search/src/main/java/com/yahoo/prelude/querytransform/NonPhrasingSearcher.java