Java example source code file (BasicObjectsTest.java)

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Java - Java tags/keywords

cummings, function, npe, nullpointerexception, object, rnn_1, rnn_2, rnn_3, some, string, supplier, thc, util, values, when

The BasicObjectsTest.java Java example source code

/*
 * Copyright (c) 2009, 2013, 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 6797535 6889858 6891113 8013712 8011800 8014365
 * @summary Basic tests for methods in java.util.Objects
 * @author  Joseph D. Darcy
 */

import java.util.*;
import java.util.function.*;

public class BasicObjectsTest {
    public static void main(String... args) {
        int errors = 0;
        errors += testEquals();
        errors += testDeepEquals();
        errors += testHashCode();
        errors += testHash();
        errors += testToString();
        errors += testToString2();
        errors += testCompare();
        errors += testRequireNonNull();
        errors += testIsNull();
        errors += testNonNull();
        if (errors > 0 )
            throw new RuntimeException();
    }

    private static int testEquals() {
        int errors = 0;
        Object[] values = {null, "42", 42};
        for(int i = 0; i < values.length; i++)
            for(int j = 0; j < values.length; j++) {
                boolean expected = (i == j);
                Object a = values[i];
                Object b = values[j];
                boolean result = Objects.equals(a, b);
                if (result != expected) {
                    errors++;
                    System.err.printf("When equating %s to %s, got %b instead of %b%n.",
                                      a, b, result, expected);
                }
            }
        return errors;
    }

    private static int testDeepEquals() {
        int errors = 0;
        Object[] values = {null,
                           null, // Change to values later
                           new byte[]  {(byte)1},
                           new short[] {(short)1},
                           new int[]   {1},
                           new long[]  {1L},
                           new char[]  {(char)1},
                           new float[] {1.0f},
                           new double[]{1.0d},
                           new String[]{"one"}};
        values[1] = values;

        for(int i = 0; i < values.length; i++)
            for(int j = 0; j < values.length; j++) {
                boolean expected = (i == j);
                Object a = values[i];
                Object b = values[j];
                boolean result = Objects.deepEquals(a, b);
                if (result != expected) {
                    errors++;
                    System.err.printf("When equating %s to %s, got %b instead of %b%n.",
                                      a, b, result, expected);
                }
            }

        return errors;
    }

    private static int testHashCode() {
        int errors = 0;
        errors += (Objects.hashCode(null) == 0 ) ? 0 : 1;
        String s = "42";
        errors += (Objects.hashCode(s) == s.hashCode() ) ? 0 : 1;
        return errors;
    }

    private static int testHash() {
        int errors = 0;

        Object[] data = new String[]{"perfect", "ham", "THC"};

        errors += ((Objects.hash((Object[])null) == 0) ? 0 : 1);

        errors += (Objects.hash("perfect", "ham", "THC") ==
                   Arrays.hashCode(data)) ? 0 : 1;

        return errors;
    }

    private static int testToString() {
        int errors = 0;
        errors += ("null".equals(Objects.toString(null)) ) ? 0 : 1;
        String s = "Some string";
        errors += (s.equals(Objects.toString(s)) ) ? 0 : 1;
        return errors;
    }

    private static int testToString2() {
        int errors = 0;
        String s = "not the default";
        errors += (s.equals(Objects.toString(null, s)) ) ? 0 : 1;
        errors += (s.equals(Objects.toString(s, "another string")) ) ? 0 : 1;
        return errors;
    }

    private static int testCompare() {
        int errors = 0;
        String[] values = {"e. e. cummings", "zzz"};
        String[] VALUES = {"E. E. Cummings", "ZZZ"};
        errors += compareTest(null, null, 0);
        for(int i = 0; i < values.length; i++) {
            String a = values[i];
            errors += compareTest(a, a, 0);
            for(int j = 0; j < VALUES.length; j++) {
                int expected = Integer.compare(i, j);
                String b = VALUES[j];
                errors += compareTest(a, b, expected);
            }
        }
        return errors;
    }

    private static int compareTest(String a, String b, int expected) {
        int errors = 0;
        int result = Objects.compare(a, b, String.CASE_INSENSITIVE_ORDER);
        if (Integer.signum(result) != Integer.signum(expected)) {
            errors++;
            System.err.printf("When comparing %s to %s, got %d instead of %d%n.",
                              a, b, result, expected);
        }
        return errors;
    }

    private static int testRequireNonNull() {
        int errors = 0;

        final String RNN_1 = "1-arg requireNonNull";
        final String RNN_2 = "2-arg requireNonNull";
        final String RNN_3 = "Supplier requireNonNull";

        Function<String, String> rnn1 = s -> Objects.requireNonNull(s);
        Function<String, String> rnn2 = s -> Objects.requireNonNull(s, "trousers");
        Function<String, String> rnn3 = s -> Objects.requireNonNull(s, () -> "trousers");

        errors += testRNN_NonNull(rnn1, RNN_1);
        errors += testRNN_NonNull(rnn2, RNN_2);
        errors += testRNN_NonNull(rnn3, RNN_3);

        errors += testRNN_Null(rnn1, RNN_1, null);
        errors += testRNN_Null(rnn2, RNN_2, "trousers");
        errors += testRNN_Null(rnn3, RNN_3, "trousers");
        return errors;
    }

    private static int testRNN_NonNull(Function<String, String> testFunc,
                                       String testFuncName) {
        int errors = 0;
        try {
            String s = testFunc.apply("pants");
            if (s != "pants") {
                System.err.printf(testFuncName + " failed to return its arg");
                errors++;
            }
        } catch (NullPointerException e) {
            System.err.printf(testFuncName + " threw unexpected NPE");
            errors++;
        }
        return errors;
    }

    private static int testRNN_Null(Function<String, String> testFunc,
                                    String testFuncName,
                                    String expectedMessage) {
        int errors = 0;
        try {
            String s = testFunc.apply(null);
            System.err.printf(testFuncName + " failed to throw NPE");
            errors++;
        } catch (NullPointerException e) {
            if (e.getMessage() != expectedMessage) {
                System.err.printf(testFuncName + " threw NPE w/ bad detail msg");
                errors++;
            }
        }
        return errors;
    }

    private static int testIsNull() {
        int errors = 0;

        errors += Objects.isNull(null) ? 0 : 1;
        errors += Objects.isNull(Objects.class) ? 1 : 0;

        return errors;
    }

    private static int testNonNull() {
        int errors = 0;

        errors += Objects.nonNull(null) ? 1 : 0;
        errors += Objects.nonNull(Objects.class) ? 0 : 1;

        return errors;
    }
}