Java tutorial
//package com.java2s; /******************************************************************************* * Breakout Cave Survey Visualizer * * Copyright (C) 2014 James Edwards * * jedwards8 at fastmail dot fm * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *******************************************************************************/ import java.util.Comparator; import java.util.List; public class Main { public static <T> void testComparator(List<? extends T> list, Comparator<T> comparator) { for (int i = 0; i < list.size(); i++) { for (int j = i; j < list.size(); j++) { T oi = list.get(i); T oj = list.get(j); int ci = comparator.compare(oi, oj); int cj = comparator.compare(oj, oi); if (Math.signum(ci) != -Math.signum(cj)) { throw new RuntimeException("Bad comparator: " + comparator + "\n\tlist.get(" + i + "): " + oi + "\n\tlist.get(" + j + "): " + oj + "\ncompare(list.get(" + i + "), list.get(" + j + ")): " + ci + "\ncompare(list.get(" + j + "), list.get(" + i + ")): " + cj); } } } } }