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Java example source code file (ArrayObjectMethods.java)

This example Java source code file (ArrayObjectMethods.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

abstractlist, boolean, byte, bytearrayinputstream, character, double, float, integer, list, long, object, objectoutputstream, short, throwable, util

The ArrayObjectMethods.java Java example source code

/*
 * Copyright (c) 2003, 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     4906359 6239296
 * @summary Basic test for content-based array object methods
 * @author  Josh Bloch, Martin Buchholz
 */

import java.util.*;
import java.io.*;

public class ArrayObjectMethods {
    int[] sizes = {0, 10, 100, 200, 1000};

    void test(String[] args) throws Throwable {
        equal(Arrays.deepToString(null), "null");
        equal(Arrays.deepToString(new Object[]{}), "[]");
        equal(Arrays.deepToString(new Object[]{null}), "[null]");
        equal(Arrays.deepToString(new Object[]{null, 1}), "[null, 1]");
        equal(Arrays.deepToString(new Object[]{1, null}), "[1, null]");
        equal(Arrays.deepToString(new Object[]{new Object[]{}, null}), "[[], null]");

        {
            Object[] a = {1, null};
            a[1] = a;
            equal(Arrays.deepToString(a), "[1, [...]]");
            a[0] = a;
            equal(Arrays.deepToString(a), "[[...], [...]]");
            a[0] = a[1] = new Object[]{1, null, a};
            equal(Arrays.deepToString(a), "[[1, null, [...]], [1, null, [...]]]");
        }

        for (int size : sizes) {
            {
                long[] a = Rnd.longArray(size);
                equal(Arrays.toString(a), PrimitiveArrays.asList(a).toString());
                equal(Arrays.hashCode(a), PrimitiveArrays.asList(a).hashCode());
            }
            {
                int[] a = Rnd.intArray(size);
                equal(Arrays.toString(a), PrimitiveArrays.asList(a).toString());
                equal(Arrays.hashCode(a), PrimitiveArrays.asList(a).hashCode());
            }
            {
                short[] a = Rnd.shortArray(size);
                equal(Arrays.toString(a), PrimitiveArrays.asList(a).toString());
                equal(Arrays.hashCode(a), PrimitiveArrays.asList(a).hashCode());
            }
            {
                char[] a = Rnd.charArray(size);
                equal(Arrays.toString(a), PrimitiveArrays.asList(a).toString());
                equal(Arrays.hashCode(a), PrimitiveArrays.asList(a).hashCode());
            }
            {
                byte[] a = Rnd.byteArray(size);
                equal(Arrays.toString(a), PrimitiveArrays.asList(a).toString());
                equal(Arrays.hashCode(a), PrimitiveArrays.asList(a).hashCode());
            }
            {
                boolean[] a = Rnd.booleanArray(size);
                equal(Arrays.toString(a), PrimitiveArrays.asList(a).toString());
                equal(Arrays.hashCode(a), PrimitiveArrays.asList(a).hashCode());
            }
            {
                double[] a = Rnd.doubleArray(size);
                equal(Arrays.toString(a), PrimitiveArrays.asList(a).toString());
                equal(Arrays.hashCode(a), PrimitiveArrays.asList(a).hashCode());
            }
            {
                float[] a = Rnd.floatArray(size);
                equal(Arrays.toString(a), PrimitiveArrays.asList(a).toString());
                equal(Arrays.hashCode(a), PrimitiveArrays.asList(a).hashCode());
            }
            {
                Object[] a = Rnd.flatObjectArray(size);
                equal(Arrays.toString(a), Arrays.asList(a).toString());
                equal(Arrays.deepToString(a), Arrays.asList(a).toString());
                equal(Arrays.hashCode(a), Arrays.asList(a).hashCode());
            }

            if (size <= 200) {
                Object[] a = Rnd.nestedObjectArray(size);
                List aList = deepToList(a);
                equal(Arrays.toString(a), Arrays.asList(a).toString());
                equal(Arrays.deepToString(a), aList.toString());
                equal(Arrays.deepHashCode(a), aList.hashCode());
                equal(Arrays.hashCode(a), Arrays.asList(a).hashCode());

                Object[] deepCopy = (Object[]) deepCopy(a);
                check(Arrays.deepEquals(a, deepCopy));
                check(Arrays.deepEquals(deepCopy, a));

                // Make deepCopy != a
                if (size == 0)
                    deepCopy = new Object[] {"foo"};
                else if (deepCopy[deepCopy.length - 1] == null)
                    deepCopy[deepCopy.length - 1] = "baz";
                else
                    deepCopy[deepCopy.length - 1] = null;
                check(! Arrays.deepEquals(a, deepCopy));
                check(! Arrays.deepEquals(deepCopy, a));
            }
        }
    }

    // Utility method to turn an array into a list "deeply," turning
    // all primitives into objects
    List<Object> deepToList(Object[] a) {
        List<Object> result = new ArrayList();
        for (Object e : a) {
            if (e instanceof byte[])
                result.add(PrimitiveArrays.asList((byte[])e));
            else if (e instanceof short[])
                result.add(PrimitiveArrays.asList((short[])e));
            else if (e instanceof int[])
                result.add(PrimitiveArrays.asList((int[])e));
            else if (e instanceof long[])
                result.add(PrimitiveArrays.asList((long[])e));
            else if (e instanceof char[])
                result.add(PrimitiveArrays.asList((char[])e));
            else if (e instanceof double[])
                result.add(PrimitiveArrays.asList((double[])e));
            else if (e instanceof float[])
                result.add(PrimitiveArrays.asList((float[])e));
            else if (e instanceof boolean[])
                result.add(PrimitiveArrays.asList((boolean[])e));
            else if (e instanceof Object[])
                result.add(deepToList((Object[])e));
            else
                result.add(e);
        }
        return result;
    }

    // Utility method to do a deep copy of an object *very slowly* using
    // serialization/deserialization
    Object deepCopy(Object oldObj) {
        try {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            ObjectOutputStream oos = new ObjectOutputStream(bos);
            oos.writeObject(oldObj);
            oos.flush();
            ByteArrayInputStream bin = new ByteArrayInputStream(
                bos.toByteArray());
            ObjectInputStream ois = new ObjectInputStream(bin);
            return ois.readObject();
        } catch(Exception e) {
            throw new IllegalArgumentException(e);
        }
    }

    //--------------------- 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 ArrayObjectMethods().instanceMain(args);}
    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");}
}

/**
 * Methods to generate "interesting" random primitives and primitive
 * arrays.  Unlike Random.nextXxx, these methods return small values
 * and boundary values (e.g., 0, -1, NaN) with greater than normal
 * likelihood.
 */

class Rnd {
    private static Random rnd = new Random();

    public static long nextLong() {
        switch(rnd.nextInt(10)) {
            case 0:  return 0;
            case 1:  return Long.MIN_VALUE;
            case 2:  return Long.MAX_VALUE;
            case 3: case 4: case 5:
                     return (long) (rnd.nextInt(20) - 10);
            default: return rnd.nextLong();
        }
    }

    public static int nextInt() {
        switch(rnd.nextInt(10)) {
            case 0:  return 0;
            case 1:  return Integer.MIN_VALUE;
            case 2:  return Integer.MAX_VALUE;
            case 3: case 4: case 5:
                     return rnd.nextInt(20) - 10;
            default: return rnd.nextInt();
        }
    }

    public static short nextShort() {
        switch(rnd.nextInt(10)) {
            case 0:  return 0;
            case 1:  return Short.MIN_VALUE;
            case 2:  return Short.MAX_VALUE;
            case 3: case 4: case 5:
                     return (short) (rnd.nextInt(20) - 10);
            default: return (short) rnd.nextInt();
        }
    }

    public static char nextChar() {
        switch(rnd.nextInt(10)) {
            case 0:  return 0;
            case 1:  return Character.MIN_VALUE;
            case 2:  return Character.MAX_VALUE;
            case 3: case 4: case 5:
                     return (char) (rnd.nextInt(20) - 10);
            default: return (char) rnd.nextInt();
        }
    }

    public static byte nextByte() {
        switch(rnd.nextInt(10)) {
            case 0:  return 0;
            case 1:  return Byte.MIN_VALUE;
            case 2:  return Byte.MAX_VALUE;
            case 3: case 4: case 5:
                     return (byte) (rnd.nextInt(20) - 10);
            default: return (byte) rnd.nextInt();
        }
    }

    public static boolean nextBoolean() {
        return rnd.nextBoolean();
    }

    public static double nextDouble() {
        switch(rnd.nextInt(20)) {
            case 0:  return 0;
            case 1:  return -0.0;
            case 2:  return Double.MIN_VALUE;
            case 3:  return Double.MAX_VALUE;
            case 4:  return Double.NaN;
            case 5:  return Double.NEGATIVE_INFINITY;
            case 6:  return Double.POSITIVE_INFINITY;
            case 7: case 8: case 9:
                     return (rnd.nextInt(20) - 10);
            default: return rnd.nextDouble();
        }
    }

    public static float nextFloat() {
        switch(rnd.nextInt(20)) {
            case 0:  return 0;
            case 1:  return -0.0f;
            case 2:  return Float.MIN_VALUE;
            case 3:  return Float.MAX_VALUE;
            case 4:  return Float.NaN;
            case 5:  return Float.NEGATIVE_INFINITY;
            case 6:  return Float.POSITIVE_INFINITY;
            case 7: case 8: case 9:
                     return (rnd.nextInt(20) - 10);
            default: return rnd.nextFloat();
        }
    }

    public static Object nextObject() {
        switch(rnd.nextInt(10)) {
            case 0:  return null;
            case 1:  return "foo";
            case 2:  case 3: case 4:
                     return Double.valueOf(nextDouble());
            default: return Integer.valueOf(nextInt());
        }
    }

    public static long[] longArray(int length) {
        long[] result = new long[length];
        for (int i = 0; i < length; i++)
            result[i] = Rnd.nextLong();
        return result;
    }

    public static int[] intArray(int length) {
        int[] result = new int[length];
        for (int i = 0; i < length; i++)
            result[i] = Rnd.nextInt();
        return result;
    }

    public static short[] shortArray(int length) {
        short[] result = new short[length];
        for (int i = 0; i < length; i++)
            result[i] = Rnd.nextShort();
        return result;
    }

    public static char[] charArray(int length) {
        char[] result = new char[length];
        for (int i = 0; i < length; i++)
            result[i] = Rnd.nextChar();
        return result;
    }

    public static byte[] byteArray(int length) {
        byte[] result = new byte[length];
        for (int i = 0; i < length; i++)
            result[i] = Rnd.nextByte();
        return result;
    }

    public static boolean[] booleanArray(int length) {
        boolean[] result = new boolean[length];
        for (int i = 0; i < length; i++)
            result[i] = Rnd.nextBoolean();
        return result;
    }

    public static double[] doubleArray(int length) {
        double[] result = new double[length];
        for (int i = 0; i < length; i++)
            result[i] = Rnd.nextDouble();
        return result;
    }

    public static float[] floatArray(int length) {
        float[] result = new float[length];
        for (int i = 0; i < length; i++)
            result[i] = Rnd.nextFloat();
        return result;
    }

    public static Object[] flatObjectArray(int length) {
        Object[] result = new Object[length];
        for (int i = 0; i < length; i++)
            result[i] = Rnd.nextObject();
        return result;
    }

    // Calling this for length >> 100 is likely to run out of memory!  It
    // should be perhaps be tuned to allow for longer arrays
    public static Object[] nestedObjectArray(int length) {
        Object[] result = new Object[length];
        for (int i = 0; i < length; i++) {
            switch(rnd.nextInt(16)) {
                case 0:  result[i] = nestedObjectArray(length/2);
                         break;
                case 1:  result[i] = longArray(length/2);
                         break;
                case 2:  result[i] = intArray(length/2);
                         break;
                case 3:  result[i] = shortArray(length/2);
                         break;
                case 4:  result[i] = charArray(length/2);
                         break;
                case 5:  result[i] = byteArray(length/2);
                         break;
                case 6:  result[i] = floatArray(length/2);
                         break;
                case 7:  result[i] = doubleArray(length/2);
                         break;
                case 8:  result[i] = longArray(length/2);
                         break;
                default: result[i] = Rnd.nextObject();
            }
        }
        return result;
    }
}

/**
 * Primitive arrays viewed as lists.  Inefficient but cool.
 * This utility should be generally useful in writing regression/unit/basic
 * tests.
 */

class PrimitiveArrays {
    public static List<Long> asList(final long[] a) {
        return new AbstractList<Long>() {
            public Long get(int i) { return a[i]; }
            public int size()      { return a.length; }

            public Long set(int i, Long e) {
                long oldVal = a[i];
                a[i] = e;
                return oldVal;
            }
        };
    }

    public static List<Integer> asList(final int[] a) {
        return new AbstractList<Integer>() {
            public Integer get(int i) { return a[i]; }
            public int size()         { return a.length; }

            public Integer set(int i, Integer e) {
                int oldVal = a[i];
                a[i] = e;
                return oldVal;
            }
        };
    }

    public static List<Short> asList(final short[] a) {
        return new AbstractList<Short>() {
            public Short get(int i) { return a[i]; }
            public int size()       { return a.length; }

            public Short set(int i, Short e) {
                short oldVal = a[i];
                a[i] = e;
                return oldVal;
            }
        };
    }

    public static List<Character> asList(final char[] a) {
        return new AbstractList<Character>() {
            public Character get(int i) { return a[i]; }
            public int size()           { return a.length; }

            public Character set(int i, Character e) {
                Character oldVal = a[i];
                a[i] = e;
                return oldVal;
            }
        };
    }

    public static List<Byte> asList(final byte[] a) {
        return new AbstractList<Byte>() {
            public Byte get(int i) { return a[i]; }
            public int size()      { return a.length; }

            public Byte set(int i, Byte e) {
                Byte oldVal = a[i];
                a[i] = e;
                return oldVal;
            }
        };
    }

    public static List<Boolean> asList(final boolean[] a) {
        return new AbstractList<Boolean>() {
            public Boolean get(int i) { return a[i]; }
            public int size()         { return a.length; }

            public Boolean set(int i, Boolean e) {
                Boolean oldVal = a[i];
                a[i] = e;
                return oldVal;
            }
        };
    }

    public static List<Double> asList(final double[] a) {
        return new AbstractList<Double>() {
            public Double get(int i) { return a[i]; }
            public int size()        { return a.length; }

            public Double set(int i, Double e) {
                Double oldVal = a[i];
                a[i] = e;
                return oldVal;
            }
        };
    }

    public static List<Float> asList(final float[] a) {
        return new AbstractList<Float>() {
            public Float get(int i) { return a[i]; }
            public int size()       { return a.length; }

            public Float set(int i, Float e) {
                Float oldVal = a[i];
                a[i] = e;
                return oldVal;
            }
        };
    }
}




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