// arrays/CompType.java // (c)2016 MindView LLC: see Copyright.txt // We make no guarantees that this code is fit for any purpose. // Visit http://mindviewinc.com/Books/OnJava/ for more book information. // Implementing Comparable in a class import java.util.*; import java.util.function.*; import onjava.*; import static onjava.ArrayShow.*; public class CompType implements Comparable { int i; int j; private static int count = 1; public CompType(int n1, int n2) { i = n1; j = n2; } @Override public String toString() { String result = "[i = " + i + ", j = " + j + "]"; if(count++ % 3 == 0) result += "\n"; return result; } @Override public int compareTo(CompType rv) { return (i < rv.i ? -1 : (i == rv.i ? 0 : 1)); } private static SplittableRandom r = new SplittableRandom(47); public static CompType get() { return new CompType(r.nextInt(100), r.nextInt(100)); } public static void main(String[] args) { CompType[] a = new CompType[12]; Arrays.setAll(a, n -> get()); show("Before sorting", a); Arrays.sort(a); show("After sorting", a); } } /* Output: before sorting: [[i = 58, j = 55], [i = 93, j = 61], [i = 61, j = 29] , [i = 68, j = 0], [i = 22, j = 7], [i = 88, j = 28] , [i = 51, j = 89], [i = 9, j = 78], [i = 98, j = 61] , [i = 20, j = 58], [i = 16, j = 40], [i = 11, j = 22] ] after sorting: [[i = 9, j = 78], [i = 11, j = 22], [i = 16, j = 40] , [i = 20, j = 58], [i = 22, j = 7], [i = 51, j = 89] , [i = 58, j = 55], [i = 61, j = 29], [i = 68, j = 0] , [i = 88, j = 28], [i = 93, j = 61], [i = 98, j = 61] ] */