Java example source code file (Correct.java)

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Java - Java tags/keywords

comparable, comparator, correct, exception, integer, integercomparator, iterations, object, random, runtimeexception, test_order, test_size, util

The Correct.java Java example source code

/*
 * Copyright (c) 2002, Oracle and/or its affiliates. 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 4726380
 * @summary Check that different sorts give equivalent results.
 */

import java.util.*;

public class Correct {

    static Random rnd = new Random();
    static final int ITERATIONS = 1000;
    static final int TEST_SIZE = 1000;

    public static void main(String[] args) throws Exception {
        Object[] array1 = null;
        Object[] array2 = null;

        for (int i=0; i<ITERATIONS; i++) {
            int size = rnd.nextInt(TEST_SIZE) + 1;
            array1 = (Object[])getIntegerArray(size);
            array2 = (Object[])array1.clone();
            Arrays.sort(array1, array1.length/3, array1.length/2);
            stupidSort(array2, array2.length/3, array2.length/2);
            if(!Arrays.equals(array1, array2))
                throw new RuntimeException("failed!");
        }

        for (int i=0; i<ITERATIONS; i++) {
            int size = rnd.nextInt(TEST_SIZE) + 1;
            array1 = (Object[])getIntegerArray(size);
            array2 = (Object[])array1.clone();
            Arrays.sort(array1, array1.length/3, array1.length/2, TEST_ORDER);
            stupidSort(array2, array2.length/3, array2.length/2);
            if(!Arrays.equals(array1, array2))
                throw new RuntimeException("failed!");
        }
    }

    static Integer[] getIntegerArray(int size) throws Exception {
        Integer[] blah = new Integer[size];
        for (int x=0; x<size; x++) {
            blah[x] = new Integer(rnd.nextInt());
        }
        return blah;
    }

    static void stupidSort(Object[] a1, int from, int to) throws Exception {
        for (int x=from; x<to; x++) {
            Object lowest = new Integer(Integer.MAX_VALUE);
            int lowestIndex = 0;
            for (int y=x; y<to; y++) {
                if (((Comparable)a1[y]).compareTo((Comparable)lowest) < 0) {
                    lowest = a1[y];
                    lowestIndex = y;
                }
            }
            if (lowestIndex != x) {
                swap(a1, x, lowestIndex);
            }
        }
    }

    static void swap(Object x[], int a, int b) {
        Object t = x[a];
        x[a] = x[b];
        x[b] = t;
    }

    private static final Comparator TEST_ORDER = new IntegerComparator();

    private static class IntegerComparator implements Comparator {
        public int compare(Object o1, Object o2) {
            Comparable c1 = (Comparable)o1;
            Comparable c2 = (Comparable)o2;
            return  c1.compareTo(c2);
        }
    }
}