@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if ( ! super.equals(o)) return false;
        if (getClass() != o.getClass()) return false;

        RegExpItem other = (RegExpItem)o;
        return Objects.equals(this.expression, other.expression);
    }
Match a field with the contained regular expression.

@author Steinar Knutsen
container-search/src/main/java/com/yahoo/prelude/query/RegExpItem.java