/*

 * Copyright (c) 2018, Red Hat, Inc. All rights reserved.

 *

 * 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.

 */

package org.openjdk.bench.java.util;

import org.openjdk.jmh.annotations.Benchmark;

import org.openjdk.jmh.annotations.BenchmarkMode;

import org.openjdk.jmh.annotations.Mode;

import org.openjdk.jmh.annotations.OutputTimeUnit;

import org.openjdk.jmh.annotations.Param;

import org.openjdk.jmh.annotations.Scope;

import org.openjdk.jmh.annotations.Setup;

import org.openjdk.jmh.annotations.State;

import java.util.HashMap;

import java.util.LinkedHashMap;

import java.util.Map;

import java.util.concurrent.ThreadLocalRandom;

import java.util.concurrent.TimeUnit;

import java.util.function.Supplier;

import java.util.stream.IntStream;

import static java.util.stream.Collectors.toMap;

@BenchmarkMode(Mode.AverageTime)

@OutputTimeUnit(TimeUnit.MILLISECONDS)

@State(Scope.Thread)

public class HashMapBench {

    private Supplier<Map<Integer, Integer>> mapSupplier;

    private Map<Integer, Integer> bigMapToAdd;

    @Param("1000000")

    private int size;

    @Param

    private MapType mapType;

    public enum MapType {

        HASH_MAP,

        LINKED_HASH_MAP,

    }

    @Setup

    public void setup() {

        switch (mapType) {

        case HASH_MAP:

            mapSupplier = () -> new HashMap<>();

            break;

        case LINKED_HASH_MAP:

            mapSupplier = () -> new LinkedHashMap<>();

            break;

        default:

            throw new AssertionError();

        }

        ThreadLocalRandom rnd = ThreadLocalRandom.current();

        this.bigMapToAdd = IntStream.range(0, size).boxed()

            .collect(toMap(i -> 7 + i * 128, i -> rnd.nextInt()));

    }

    @Benchmark

    public int putAllWithBigMapToNonEmptyMap() {

        Map<Integer, Integer> map = mapSupplier.get();

        map.put(-1, -1);

        map.putAll(bigMapToAdd);

        return map.size();

    }

    @Benchmark

    public int putAllWithBigMapToEmptyMap() {

        Map<Integer, Integer> map = mapSupplier.get();

        map.putAll(bigMapToAdd);

        return map.size();

    }

    @Benchmark

    public int put() {

        Map<Integer, Integer> map = mapSupplier.get();

        for (int k : bigMapToAdd.keySet()) {

            map.put(k, bigMapToAdd.get(k));

        }

        return map.size();

    }

}