package org.openjdk.gcbench.fragger;

import org.openjdk.jmh.annotations.*;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.TimeUnit;


@Warmup(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
@Fork(value = 1)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Threads(1)
@State(Scope.Benchmark)
public class CHMFragger {

    static final int PAYLOAD_SIZE = 4096;

    @Param({"1000"})
    int size;

    Object[] keys;
    Map<Object, Object> cache;

    @Setup
    public void setup() {
        keys = new Object[size];
        cache = new ConcurrentHashMap<>();
        for (int c = 0; c < size; c++) {
            Object k = new Object();
            keys[c] = k;
            cache.put(k, new byte[PAYLOAD_SIZE]);
        }
    }

    @Benchmark
    public Object test() {
        ThreadLocalRandom tlr = ThreadLocalRandom.current();
        int idx = tlr.nextInt(size);
        if (tlr.nextInt(5) == 0) {
            Object pk = keys[idx];
            Object nk = new Object();
            byte[] v = new byte[PAYLOAD_SIZE];
            cache.put(nk, v);
            cache.remove(pk);
            keys[idx] = nk;
            return v;
        } else {
            return cache.get(keys[idx]);
        }
    }


}