test/java/util/Map/LockStep.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
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 *
 * 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.
 *
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 */

/*
 * @test
 * @bug 6612102
 * @summary Test Map implementations for mutual compatibility
 */

import java.util.*;
import java.util.concurrent.*;

/**
 * Based on the strange scenario required to reproduce
 * (coll) IdentityHashMap.iterator().remove() might decrement size twice
 *
 * It would be good to add more "Lockstep-style" tests to this file.
 */
public class LockStep {
    void mapsEqual(Map m1, Map m2) {
        equal(m1, m2);
        equal(m2, m1);
        equal(m1.size(), m2.size());
        equal(m1.isEmpty(), m2.isEmpty());
        equal(m1.keySet(), m2.keySet());
        equal(m2.keySet(), m1.keySet());
    }

    void mapsEqual(List<Map> maps) {
        Map first = maps.get(0);
        for (Map map : maps)
            mapsEqual(first, map);
    }

    void put(List<Map> maps, Object key, Object val) {
        for (Map map : maps)
            map.put(key, val);
        mapsEqual(maps);
    }

    void removeLastTwo(List<Map> maps) {
        Map first = maps.get(0);
        int size = first.size();
        Iterator fit = first.keySet().iterator();
        for (int j = 0; j < size - 2; j++)
            fit.next();
        Object x1 = fit.next();
        Object x2 = fit.next();

        for (Map map : maps) {
            Iterator it = map.keySet().iterator();
            while (it.hasNext()) {
                Object x = it.next();
                if (x == x1 || x == x2)
                    it.remove();
            }
        }
        mapsEqual(maps);
    }

    void remove(Map m, Iterator it) {
        int size = m.size();
        it.remove();
        if (m.size() != size-1)
            throw new Error(String.format("Incorrect size!%nmap=%s, size=%d%n",
                                          m.toString(), m.size()));
    }

    void test(String[] args) throws Throwable {
        final int iterations = 100;
        final Random r = new Random();

        for (int i = 0; i < iterations; i++) {
            List<Map> maps = Arrays.asList(
                new Map[] {
                    new IdentityHashMap(11),
                    new HashMap(16),
                    new LinkedHashMap(16),
                    new WeakHashMap(16),
                    new Hashtable(16),
                    new TreeMap(),
                    new ConcurrentHashMap(16),
                    new ConcurrentSkipListMap() });

            for (int j = 0; j < 10; j++)
                put(maps, r.nextInt(100), r.nextInt(100));
            removeLastTwo(maps);
        }
    }

    //--------------------- 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 LockStep().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");}
}