Java example source code file (UUIDTest.java)

This example Java source code file (UUIDTest.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

equal, exception, expected, ffffffff\-ffff\-1fff\-8a5a\-be785f17dcda, incorrect, linkedlist, random, runtimeexception, unsupportedoperationexception, util, uuid, uuids, uuidtest

The UUIDTest.java Java example source code

/*
 * Copyright (c) 2003, 2012, 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 4173528 5068772
 * @summary Unit tests for java.util.UUID
 */

import java.util.*;

public class UUIDTest {

    static Random generator = new Random();

    public static void main(String[] args) throws Exception {
        containsTest();
        randomUUIDTest();
        nameUUIDFromBytesTest();
        stringTest();
        versionTest();
        variantTest();
        timestampTest();
        clockSequenceTest();
        nodeTest();
        hashCodeEqualsTest();
        compareTo();
    }

    // Verify that list.contains detects UUID collisons
    private static void containsTest() throws Exception {
        List list = new LinkedList();
        list.add(new UUID(4,4));
        if (!list.contains(new UUID(4,4)))
            throw new Exception("contains test did not work as expected");
    }

    private static void randomUUIDTest() throws Exception {
        List list = new LinkedList();
        for (int i=0; i<100; i++) {
            UUID u1 = UUID.randomUUID();
            if (4 != u1.version()) {
                throw new Exception("bad version");
            }
            if (2 != u1.variant()) {
                throw new Exception("bad variant");
            }
            if (list.contains(u1))
                throw new Exception("random UUID collision very unlikely");
            list.add(u1);
        }
    }

    private static void nameUUIDFromBytesTest() throws Exception {
        Random byteSource = new Random();
        byte[] someBytes = new byte[12];
        List list = new LinkedList();
        for (int i=0; i<100; i++) {
            byteSource.nextBytes(someBytes);
            UUID u1 = UUID.nameUUIDFromBytes(someBytes);
            if (3 != u1.version()) {
                throw new Exception("bad version");
            }
            if (2 != u1.variant()) {
                throw new Exception("bad variant");
            }
            if (list.contains(u1))
                throw new Exception("byte UUID collision very unlikely");
            list.add(u1);
        }
    }

    private static void stringTest() throws Exception {
        for (int i=0; i<100; i++) {
            UUID u1 = UUID.randomUUID();
            UUID u2 = UUID.fromString(u1.toString());
            if (!u1.equals(u2))
                throw new Exception("UUID -> string -> UUID failed");
        }
    }

    private static void versionTest() throws Exception {
        UUID test = UUID.randomUUID();
        if (test.version() != 4)
            throw new Exception("randomUUID not type 4");
        Random byteSource = new Random();
        byte[] someBytes = new byte[12];
        byteSource.nextBytes(someBytes);
        test = UUID.nameUUIDFromBytes(someBytes);
        if (test.version() != 3)
            throw new Exception("nameUUIDFromBytes not type 3");
        test = UUID.fromString("9835451d-e2e0-1e41-8a5a-be785f17dcda");
        if (test.version() != 1)
            throw new Exception("wrong version fromString 1");
        test = UUID.fromString("9835451d-e2e0-2e41-8a5a-be785f17dcda");
        if (test.version() != 2)
            throw new Exception("wrong version fromString 2");
        test = UUID.fromString("9835451d-e2e0-3e41-8a5a-be785f17dcda");
        if (test.version() != 3)
            throw new Exception("wrong version fromString 3");
        test = UUID.fromString("9835451d-e2e0-4e41-8a5a-be785f17dcda");
        if (test.version() != 4)
            throw new Exception("wrong version fromString 4");
        test = new UUID(0x0000000000001000L, 55L);
        if (test.version() != 1)
            throw new Exception("wrong version from bit set to 1");
        test = new UUID(0x0000000000002000L, 55L);
        if (test.version() != 2)
            throw new Exception("wrong version from bit set to 2");
        test = new UUID(0x0000000000003000L, 55L);
        if (test.version() != 3)
            throw new Exception("wrong version from bit set to 3");
        test = new UUID(0x0000000000004000L, 55L);
        if (test.version() != 4)
            throw new Exception("wrong version from bit set to 4");
    }

    private static void variantTest() throws Exception {
        UUID test = UUID.randomUUID();
        if (test.variant() != 2)
            throw new Exception("randomUUID not variant 2");
        Random byteSource = new Random();
        byte[] someBytes = new byte[12];
        byteSource.nextBytes(someBytes);
        test = UUID.nameUUIDFromBytes(someBytes);
        if (test.variant() != 2)
            throw new Exception("nameUUIDFromBytes not variant 2");
        test = new UUID(55L, 0x0000000000001000L);
        if (test.variant() != 0)
            throw new Exception("wrong variant from bit set to 0");
        test = new UUID(55L, 0x8000000000001000L);
        if (test.variant() != 2)
            throw new Exception("wrong variant from bit set to 2");
       test = new UUID(55L, 0xc000000000001000L);
        if (test.variant() != 6)
            throw new Exception("wrong variant from bit set to 6");
       test = new UUID(55L, 0xe000000000001000L);
        if (test.variant() != 7)
            throw new Exception("wrong variant from bit set to 7");
    }

    private static void timestampTest() throws Exception {
        UUID test = UUID.randomUUID();
        try {
            test.timestamp();
            throw new Exception("Expected exception not thrown");
        } catch (UnsupportedOperationException uoe) {
            // Correct result
        }
        test = UUID.fromString("00000001-0000-1000-8a5a-be785f17dcda");
        if (test.timestamp() != 1)
            throw new Exception("Incorrect timestamp");
        test = UUID.fromString("00000400-0000-1000-8a5a-be785f17dcda");
        if (test.timestamp() != 1024)
            throw new Exception("Incorrect timestamp");
        test = UUID.fromString("FFFFFFFF-FFFF-1FFF-8a5a-be785f17dcda");
        if (test.timestamp() != Long.MAX_VALUE>>3)
            throw new Exception("Incorrect timestamp");
    }

    private static void clockSequenceTest() throws Exception {
        UUID test = UUID.randomUUID();
        try {
            test.clockSequence();
            throw new Exception("Expected exception not thrown");
        } catch (UnsupportedOperationException uoe) {
            // Correct result
        }
        test = UUID.fromString("00000001-0000-1000-8001-be785f17dcda");
        if (test.clockSequence() != 1)
            throw new Exception("Incorrect sequence");
        test = UUID.fromString("00000001-0000-1000-8002-be785f17dcda");
        if (test.clockSequence() != 2)
            throw new Exception("Incorrect sequence");
        test = UUID.fromString("00000001-0000-1000-8010-be785f17dcda");
        if (test.clockSequence() != 16)
            throw new Exception("Incorrect sequence");
        test = UUID.fromString("00000001-0000-1000-bFFF-be785f17dcda");
        if (test.clockSequence() != ((2L<<13)-1)) // 2^14 - 1
            throw new Exception("Incorrect sequence");
    }

    private static void nodeTest() throws Exception {
        UUID test = UUID.randomUUID();
        try {
            test.node();
            throw new Exception("Expected exception not thrown");
        } catch (UnsupportedOperationException uoe) {
            // Correct result
        }
        test = UUID.fromString("00000001-0000-1000-8001-000000000001");
        if (test.node() != 1)
            throw new Exception("Incorrect node");
        test = UUID.fromString("00000001-0000-1000-8002-FFFFFFFFFFFF");
        if (test.node() != ((2L<<47)-1)) // 2^48 - 1
            throw new Exception("Incorrect node");
    }

    private static void hashCodeEqualsTest() throws Exception {
        // If two UUIDs are equal they must have the same hashCode
        for (int i=0; i<100; i++) {
            UUID u1 = UUID.randomUUID();
            UUID u2 = UUID.fromString(u1.toString());
            if (u1.hashCode() != u2.hashCode())
                throw new Exception("Equal UUIDs with different hashcodes");
        }
        // Test equality of UUIDs with tampered bits
        for (int i=0; i<1000; i++) {
            long l = generator.nextLong();
            long l2 = generator.nextLong();
            int position = generator.nextInt(64);
            UUID u1 = new UUID(l, l2);
            l = l ^ (1L << position);
            UUID u2 = new UUID(l, l2);
            if (u1.equals(u2))
                throw new Exception("UUIDs with different bits equal");
        }
    }

    private static void compareTo() throws Exception {
        UUID id = new UUID(33L, 63L);
        UUID id2 = new UUID(34L, 62L);
        UUID id3 = new UUID(34L, 63L);
        UUID id4 = new UUID(34L, 64L);
        UUID id5 = new UUID(35L, 63L);

        if ((id.compareTo(id2) >= 0) ||
            (id2.compareTo(id3) >= 0) ||
            (id3.compareTo(id4) >= 0) ||
            (id4.compareTo(id5) >= 0))
            throw new RuntimeException("compareTo failure");

        if ((id5.compareTo(id4) <= 0) ||
            (id4.compareTo(id3) <= 0) ||
            (id3.compareTo(id2) <= 0) ||
            (id2.compareTo(id) <= 0))
            throw new RuntimeException("compareTo failure");

        if (id.compareTo(id) != 0)
            throw new RuntimeException("compareTo failure");

    }

}