Use Comparator to sort more than one column

[Wiyanto Ngasinur]

I'm using comparator interface to sort list of object.
Problem comes when there are more than one column to sort. For example :
I've unsorted tables :
Id|Department|Sub Department
1 Test Sub Test
2 Abap Sub Abap2
3 Abap Sub Abap1

How do i have two sort, Department then sub department. It become :
Id|Department|Sub Department
3 Abap Sub Abap1
2 Abap Sub Abap2
1 Test Sub Test

I'm implementing Comparator interface :

  
public int compare(Dept o1, Dept o2) {
	return o1.getDept().compareTo(o2.getDept()) + o1.getSubDept().compareTo(o2.getSubDept());
}

but it doesn't worked. Any idea ?

[Ernest Friedman-Hill]

It's more like

int dept = o1.getDept().compareTo(o2.getDept());
if (dept == 0)
    return o1.getSubDept().compareTo(o.getSubDept());
else
    return dept;

You compare using the second key only of the first keys are equal.

[Wiyanto Ngasinur]

thanks, you save me a lot time.