Java example source code file (Compare.java)

This example Java source code file (Compare.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

assertionerror, compare, exception, object, random, some, throwable, util

The Compare.java Java example source code

/*
 * Copyright 2009 Google, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * @test
 * @bug 6582946
 * @summary Test the primitive wrappers compare and compareTo methods
 */

import java.util.Random;

public class Compare {

    final Random rnd = new Random();

    boolean toBoolean(long x) { return x > 0; }

    void compareAll(long x, long y) {
        check(Double.compare(x, y) ==
              Double.valueOf(x).compareTo(Double.valueOf(y)));
        check(Float.compare(x, y) ==
              Float.valueOf(x).compareTo(Float.valueOf(y)));
        check(Long.compare(x, y) ==
              Long.valueOf(x).compareTo(Long.valueOf(y)));
        check(Integer.compare((int) x, (int) y) ==
              Integer.valueOf((int) x).compareTo(Integer.valueOf((int) y)));
        check(Short.compare((short) x, (short) y) ==
              Short.valueOf((short) x).compareTo(Short.valueOf((short) y)));
        check(Character.compare((char) x, (char) y) ==
              Character.valueOf((char) x).compareTo(Character.valueOf((char) y)));
        check(Byte.compare((byte) x, (byte) y) ==
              Byte.valueOf((byte) x).compareTo(Byte.valueOf((byte) y)));
        check(Boolean.compare(toBoolean(x), toBoolean(y)) ==
              Boolean.valueOf(toBoolean(x)).compareTo(Boolean.valueOf(toBoolean(y))));

        check(Double.compare(x, y) == -Double.compare(y, x));
        check(Float.compare(x, y) == -Float.compare(y, x));
        check(Long.compare(x, y) == -Long.compare(y, x));
        check(Integer.compare((int) x, (int) y) ==
              -Integer.compare((int) y, (int) x));
        check(Short.compare((short) x, (short) y) ==
              -Short.compare((short) y, (short) x));
        check(Character.compare((char) x, (char) y) ==
              -Character.compare((char) y, (char) x));
        check(Byte.compare((byte) x, (byte) y) ==
              -Byte.compare((byte) y, (byte) x));

        equal(Long.compare(x, y),
              x < y ? -1 : x > y ? 1 : 0);

        {
            int a = (int) x, b = (int) y;
            equal(Integer.compare(a, b),
                  a < b ? -1 : a > b ? 1 : 0);
        }

        {
            short a = (short) x, b = (short) y;
            equal(Short.compare(a, b),
                  a - b);
        }

        {
            char a = (char) x, b = (char) y;
            equal(Character.compare(a, b),
                  a - b);
        }

        {
            byte a = (byte) x, b = (byte) y;
            equal(Byte.compare(a, b),
                  a - b);
        }

        {
            boolean a = toBoolean(x), b = toBoolean(y);
            equal(Boolean.compare(a, b),
                  a == b ? 0 : a ? 1 : -1);
        }
    }

    void test(String args[]) throws Exception {
        long[] longs = {
            Long.MIN_VALUE,
            Integer.MIN_VALUE,
            Short.MIN_VALUE,
            Character.MIN_VALUE,
            Byte.MIN_VALUE,
            -1, 0, 1,
            Byte.MAX_VALUE,
            Character.MAX_VALUE,
            Short.MAX_VALUE,
            Integer.MAX_VALUE,
            Long.MAX_VALUE,
            rnd.nextLong(),
            rnd.nextInt(),
        };

        for (long x : longs) {
            for (long y : longs) {
                compareAll(x, y);
            }
        }
    }

    //--------------------- Infrastructure ---------------------------
    volatile int passed = 0, failed = 0;
    void pass() {passed++;}
    void fail() {failed++; Thread.dumpStack();}
    void fail(String msg) {System.err.println(msg); fail();}
    void unexpected(Throwable t) {failed++; t.printStackTrace();}
    void check(boolean cond) {if (cond) pass(); else fail();}
    void equal(Object x, Object y) {
        if (x == null ? y == null : x.equals(y)) pass();
        else fail(x + " not equal to " + y);}
    public static void main(String[] args) throws Throwable {
        new Compare().instanceMain(args);}
    public void instanceMain(String[] args) throws Throwable {
        try {test(args);} catch (Throwable t) {unexpected(t);}
        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
        if (failed > 0) throw new AssertionError("Some tests failed");}
}