I have a list of object i want to sort it using two properties. i have searched on internet and i find this solution in java 8.
class ClassA {
String var2;
String var1;
// getters and setters
}
List<classA> list;
list.sort(Comparator.comparing(ClassA::getVar1).thenComparing(ClassA::getVar2));
this absolutely works and perfectly, but what I want is to use descending sorting on var2 and ascending sorting on var1.
As simple as adding a reversed...
list.sort(Comparator.comparing(ClassA::getVar1)
.thenComparing(Comparator.comparing(ClassA::getVar2).reversed()));
You need to implement the Comparable interface.
Somtehing like this :
class A implements Comparable{
@Override public int compareTo(A anObjectA) {
if (this == anObjectA) return 0;
int ret = var2.compareTo(anObjectA.var2);
if(ret == 0)
...
}
}
You could make use of the java comparable interface. Something like this could work:
import java.util.*;
class classAComparator implements Comparator{
public int compareTo(classA a,classA b){
int res = a.var2.compareTo(b.var2);
if(res == 0) { //var2 was the same
//compare using var1 in descending order
}
return res;
}
You would use this by running list.sort(new classAComparator())
ClassA::var2twice in your example.