/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License.
 */
package org.apache.groovy.perf;

import org.apache.groovy.plugin.GroovyRunner;
import org.apache.groovy.plugin.GroovyRunnerRegistry;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.infra.Blackhole;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;

/**
 * Benchmark comparing GroovyRunnerRegistry iteration against plain list iteration.
 */
@Warmup(iterations = 3, time = 2, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 5, time = 2, timeUnit = TimeUnit.SECONDS)
@Fork(2)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@State(Scope.Thread)
public class RunnerRegistryBench {

    /**
     * Baseline list used for plain iteration comparisons.
     */
    static List<Object> control = new ArrayList<>();

    /**
     * Registry instance iterated by the benchmark.
     */
    static GroovyRunnerRegistry registry = GroovyRunnerRegistry.getInstance();
    static {
        control.add(new Object());
        control.add(new Object());
        control.add(new Object());
        registry.load(RunnerRegistryBench.class.getClassLoader());
    }

    /**
     * Benchmark iteration over the GroovyRunnerRegistry.
     * @param bh the blackhole for consuming results
     */
    @Benchmark
    public void registryIterator(Blackhole bh) {
        for (GroovyRunner runner : registry) {
            bh.consume(runner);
        }
    }

    /**
     * Benchmark iteration over a plain list (baseline).
     * @param bh the blackhole for consuming results
     */
    @Benchmark
    public void listIterator(Blackhole bh) {
        for (Object obj : control) {
            bh.consume(obj);
        }
    }

}
