4.5.3. getCheckIds

The getCheckIds method has to return the list of checks that the rule provides. In our example, this method just returns the IDs of the two checks, namely "check_length" and "check_empty_span":
public String[] getCheckIds()
{
    return new String[] { CHECK_LENGTH, CHECK_EMPTY_SPAN };
}
Note that an implementation of this method always has to return at least one check ID.