@Override
        public boolean equals(Object obj) {
            if (obj == null) {
                return false;
            }
            if (getClass() != obj.getClass()) {
                return false;
            }
            final Key other = (Key) obj;
            if (this.from != other.from && (this.from == null || !this.from.equals(other.from))) {
                return false;
            }
            if (this.to != other.to && (this.to == null || !this.to.equals(other.to))) {
                return false;
            }
            return true;
        }