@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Edge other = (Edge) obj;
		if (p1 == null) {
			if (other.p1 != null)
				return false;
		} else if (!p1.equals(other.p1))
			return false;
		if (p2 == null) {
			if (other.p2 != null)
				return false;
		} else if (!p2.equals(other.p2))
			return false;
		return true;
	}