Java sort based on two columns

Question

Lets say I have table like this:

 String | Int1 | Int2
 "foo"    5      0
 "faa"    4      1
 "zaa"    0      1
 "zoo"    4      2
 "laa"    4      3
 "loo"    1      4

What I would like to get is table like this:

 String | Int1 | Int2
 "foo"    5      0
 "laa"    4      3
 "zoo"    4      2
 "faa"    4      1
 "loo"    1      4
 "zaa"    0      1

First thing that happens is sort based on column Int1.

Second thing that happens is sort of based on column Int2 but only on rows that have same numbers in column Int1

How should I approach this problem without using any database engine?

Answer 1

You'd normally do this with a List<Item> where Item is a type containing all three values ("foo", 5, 0 for the first row, for example).

You'd then write a Comparator<Item> which compared the Int1 values of the two Item objects presented to it in compare, and if that gave a definite answer, returned that answer... and otherwise compared the Int2 values.