@Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        ArraySelectorNode other = (ArraySelectorNode) obj;
        if (selector == null) {
            if (other.selector != null)
                return false;
        } else if (!selector.equals(other.selector))
            return false;
        if (subject == null) {
            if (other.subject != null)
                return false;
        } else if (!subject.equals(other.subject))
            return false;
        return true;
    }