if (this.getClass() != o.getClass())
if (o == null || this.getClass() != o.getClass())
	public boolean equals(Object o) {		if (this.getClass() != o.getClass())			return false;		Edge other = (Edge) o;		return this.getSource() == other.getSource() && this.getTarget() == other.getTarget()		        && this.getType() == other.getType();	}