@Override
public int hashCode() {
return 17 * ((first != null) ? first.hashCode() : 0)
+ 17 * ((second != null) ? second.hashCode() : 0);
}
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((first == null) ? 0 : first.hashCode());
return result;
}