/*

 * Copyright (c) 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 7126277

 * @run main Collisions -shortrun

 * @summary Ensure Maps behave well with lots of hashCode() collisions.

 * @author Mike Duigou

 */

import java.util.*;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.ConcurrentSkipListMap;

public class Collisions {

    /**

     * Number of elements per map.

     */

    private static final int TEST_SIZE = 5000;

    final static class HashableInteger implements Comparable<HashableInteger> {

        final int value;

        final int hashmask; //yes duplication

        HashableInteger(int value, int hashmask) {

            this.value = value;

            this.hashmask = hashmask;

        }

        @Override

        public boolean equals(Object obj) {

            if (obj instanceof HashableInteger) {

                HashableInteger other = (HashableInteger) obj;

                return other.value == value;

            }

            return false;

        }

        @Override

        public int hashCode() {

            return value % hashmask;

        }

        @Override

        public int compareTo(HashableInteger o) {

            return value - o.value;

        }

        @Override

        public String toString() {

            return Integer.toString(value);

        }

    }

    private static Object[][] makeTestData(int size) {

        HashableInteger UNIQUE_OBJECTS[] = new HashableInteger[size];

        HashableInteger COLLIDING_OBJECTS[] = new HashableInteger[size];

        String UNIQUE_STRINGS[] = new String[size];

        String COLLIDING_STRINGS[] = new String[size];

        for (int i = 0; i < size; i++) {

            UNIQUE_OBJECTS[i] = new HashableInteger(i, Integer.MAX_VALUE);

            COLLIDING_OBJECTS[i] = new HashableInteger(i, 10);

            UNIQUE_STRINGS[i] = unhash(i);

            COLLIDING_STRINGS[i] = (0 == i % 2)

                    ? UNIQUE_STRINGS[i / 2]

                    : "\u0000\u0000\u0000\u0000\u0000" + COLLIDING_STRINGS[i - 1];

        }

     return new Object[][] {

            new Object[]{"Unique Objects", UNIQUE_OBJECTS},

            new Object[]{"Colliding Objects", COLLIDING_OBJECTS},

            new Object[]{"Unique Strings", UNIQUE_STRINGS},

            new Object[]{"Colliding Strings", COLLIDING_STRINGS}

        };

    }

    /**

     * Returns a string with a hash equal to the argument.

     *

     * @return string with a hash equal to the argument.

     */

    public static String unhash(int target) {

        StringBuilder answer = new StringBuilder();

        if (target < 0) {

            // String with hash of Integer.MIN_VALUE, 0x80000000

            answer.append("\\u0915\\u0009\\u001e\\u000c\\u0002");

            if (target == Integer.MIN_VALUE) {

                return answer.toString();

            }

            // Find target without sign bit set

            target = target & Integer.MAX_VALUE;

        }

        unhash0(answer, target);

        return answer.toString();

    }

    private static void unhash0(StringBuilder partial, int target) {

        int div = target / 31;

        int rem = target % 31;

        if (div <= Character.MAX_VALUE) {

            if (div != 0) {

                partial.append((char) div);

            }

            partial.append((char) rem);

        } else {

            unhash0(partial, div);

            partial.append((char) rem);

        }

    }

    private static void realMain(String[] args) throws Throwable {

        boolean shortRun = args.length > 0 && args[0].equals("-shortrun");

        Object[][] mapKeys = makeTestData(shortRun ? (TEST_SIZE / 2) : TEST_SIZE);

        // loop through data sets

        for (Object[] keys_desc : mapKeys) {

            Map<Object, Object>[] maps = (Map<Object, Object>[]) new Map[]{

                        new HashMap<>(),

                        new Hashtable<>(),

                        new IdentityHashMap<>(),

                        new LinkedHashMap<>(),

                        new TreeMap<>(),

                        new WeakHashMap<>(),

                        new ConcurrentHashMap<>(),

                        new ConcurrentSkipListMap<>()

                    };

            // for each map type.

            for (Map<Object, Object> map : maps) {

                String desc = (String) keys_desc[0];

                Object[] keys = (Object[]) keys_desc[1];

                try {

                    testMap(map, desc, keys);

                } catch(Exception all) {

                    unexpected("Failed for " + map.getClass().getName() + " with " + desc, all);

                }

            }

        }

    }

    private static <T> void testMap(Map<T, T> map, String keys_desc, T[] keys) {

        System.out.println(map.getClass() + " : " + keys_desc);

        System.out.flush();

        testInsertion(map, keys_desc, keys);

        if (keys[0] instanceof HashableInteger) {

            testIntegerIteration((Map<HashableInteger, HashableInteger>) map, (HashableInteger[]) keys);

        } else {

            testStringIteration((Map<String, String>) map, (String[]) keys);

        }

        testContainsKey(map, keys_desc, keys);

        testRemove(map, keys_desc, keys);

        map.clear();

        testInsertion(map, keys_desc, keys);

        testKeysIteratorRemove(map, keys_desc, keys);

        map.clear();

        testInsertion(map, keys_desc, keys);

        testValuesIteratorRemove(map, keys_desc, keys);

        map.clear();

        testInsertion(map, keys_desc, keys);

        testEntriesIteratorRemove(map, keys_desc, keys);

        check(map.isEmpty());

    }

    private static <T> void testInsertion(Map<T, T> map, String keys_desc, T[] keys) {

        check("map empty", (map.size() == 0) && map.isEmpty());

        for (int i = 0; i < keys.length; i++) {

            check(String.format("insertion: map expected size m%d != i%d", map.size(), i),

                    map.size() == i);

            check(String.format("insertion: put(%s[%d])", keys_desc, i), null == map.put(keys[i], keys[i]));

            check(String.format("insertion: containsKey(%s[%d])", keys_desc, i), map.containsKey(keys[i]));

            check(String.format("insertion: containsValue(%s[%d])", keys_desc, i), map.containsValue(keys[i]));

        }

        check(String.format("map expected size m%d != k%d", map.size(), keys.length),

                map.size() == keys.length);

    }

    private static void testIntegerIteration(Map<HashableInteger, HashableInteger> map, HashableInteger[] keys) {

        check(String.format("map expected size m%d != k%d", map.size(), keys.length),

                map.size() == keys.length);

        BitSet all = new BitSet(keys.length);

        for (Map.Entry<HashableInteger, HashableInteger> each : map.entrySet()) {

            check("Iteration: key already seen", !all.get(each.getKey().value));

            all.set(each.getKey().value);

        }

        all.flip(0, keys.length);

        check("Iteration: some keys not visited", all.isEmpty());

        for (HashableInteger each : map.keySet()) {

            check("Iteration: key already seen", !all.get(each.value));

            all.set(each.value);

        }

        all.flip(0, keys.length);

        check("Iteration: some keys not visited", all.isEmpty());

        int count = 0;

        for (HashableInteger each : map.values()) {

            count++;

        }

        check(String.format("Iteration: value count matches size m%d != c%d", map.size(), count),

                map.size() == count);

    }

    private static void testStringIteration(Map<String, String> map, String[] keys) {

        check(String.format("map expected size m%d != k%d", map.size(), keys.length),

                map.size() == keys.length);

        BitSet all = new BitSet(keys.length);

        for (Map.Entry<String, String> each : map.entrySet()) {

            String key = each.getKey();

            boolean longKey = key.length() > 5;

            int index = key.hashCode() + (longKey ? keys.length / 2 : 0);

            check("key already seen", !all.get(index));

            all.set(index);

        }

        all.flip(0, keys.length);

        check("some keys not visited", all.isEmpty());

        for (String each : map.keySet()) {

            boolean longKey = each.length() > 5;

            int index = each.hashCode() + (longKey ? keys.length / 2 : 0);

            check("key already seen", !all.get(index));

            all.set(index);

        }

        all.flip(0, keys.length);

        check("some keys not visited", all.isEmpty());

        int count = 0;

        for (String each : map.values()) {

            count++;

        }

        check(String.format("value count matches size m%d != k%d", map.size(), keys.length),

                map.size() == keys.length);

    }

    private static <T> void testContainsKey(Map<T, T> map, String keys_desc, T[] keys) {

        for (int i = 0; i < keys.length; i++) {

            T each = keys[i];

            check("containsKey: " + keys_desc + "[" + i + "]" + each, map.containsKey(each));

        }

    }

    private static <T> void testRemove(Map<T, T> map, String keys_desc, T[] keys) {

        check(String.format("remove: map expected size m%d != k%d", map.size(), keys.length),

                map.size() == keys.length);

        for (int i = 0; i < keys.length; i++) {

            T each = keys[i];

            check("remove: " + keys_desc + "[" + i + "]" + each, null != map.remove(each));

        }

        check(String.format("remove: map empty. size=%d", map.size()),

                (map.size() == 0) && map.isEmpty());

    }

    private static <T> void testKeysIteratorRemove(Map<T, T> map, String keys_desc, T[] keys) {

        check(String.format("remove: map expected size m%d != k%d", map.size(), keys.length),

                map.size() == keys.length);

        Iterator<T> each = map.keySet().iterator();

        while (each.hasNext()) {

            T t = each.next();

            each.remove();

            check("not removed: " + each, !map.containsKey(t) );

        }

        check(String.format("remove: map empty. size=%d", map.size()),

                (map.size() == 0) && map.isEmpty());

    }

    private static <T> void testValuesIteratorRemove(Map<T, T> map, String keys_desc, T[] keys) {

        check(String.format("remove: map expected size m%d != k%d", map.size(), keys.length),

                map.size() == keys.length);

        Iterator<T> each = map.values().iterator();

        while (each.hasNext()) {

            T t = each.next();

            each.remove();

            check("not removed: " + each, !map.containsValue(t) );

        }

        check(String.format("remove: map empty. size=%d", map.size()),

                (map.size() == 0) && map.isEmpty());

    }

    private static <T> void testEntriesIteratorRemove(Map<T, T> map, String keys_desc, T[] keys) {

        check(String.format("remove: map expected size m%d != k%d", map.size(), keys.length),

                map.size() == keys.length);

        Iterator<Map.Entry<T,T>> each = map.entrySet().iterator();

        while (each.hasNext()) {

            Map.Entry<T,T> t = each.next();

            T key = t.getKey();

            T value = t.getValue();

            each.remove();

            check("not removed: " + each, (map instanceof IdentityHashMap) || !map.entrySet().contains(t) );

            check("not removed: " + each, !map.containsKey(key) );

            check("not removed: " + each, !map.containsValue(value));

        }

        check(String.format("remove: map empty. size=%d", map.size()),

                (map.size() == 0) && map.isEmpty());

    }

    //--------------------- Infrastructure ---------------------------

    static volatile int passed = 0, failed = 0;

    static void pass() {

        passed++;

    }

    static void fail() {

        failed++;

        (new Error("Failure")).printStackTrace(System.err);

    }

    static void fail(String msg) {

        failed++;

        (new Error("Failure: " + msg)).printStackTrace(System.err);

    }

    static void abort() {

        fail();

        System.exit(1);

    }

    static void abort(String msg) {

        fail(msg);

        System.exit(1);

    }

    static void unexpected(String msg, Throwable t) {

        System.err.println("Unexpected: " + msg);

        unexpected(t);

    }

    static void unexpected(Throwable t) {

        failed++;

        t.printStackTrace(System.err);

    }

    static void check(boolean cond) {

        if (cond) {

            pass();

        } else {

            fail();

        }

    }

    static void check(String desc, boolean cond) {

        if (cond) {

            pass();

        } else {

            fail(desc);

        }

    }

    static void equal(Object x, Object y) {

        if (Objects.equals(x, y)) {

            pass();

        } else {

            fail(x + " not equal to " + y);

        }

    }

    public static void main(String[] args) throws Throwable {

        Thread.currentThread().setName(Collisions.class.getName());

//        Thread.currentThread().setPriority(Thread.MAX_PRIORITY);

        try {

            realMain(args);

        } catch (Throwable t) {

            unexpected(t);

        }

        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);

        if (failed > 0) {

            throw new Error("Some tests failed");

        }

    }

}