/*
 * Copyright 1999-2015 dangdang.com.
 * <p>
 * Licensed 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.
 * </p>
 */

package io.elasticjob.cloud.executor.handler;

import io.elasticjob.cloud.executor.handler.impl.DefaultExecutorServiceHandler;
import lombok.RequiredArgsConstructor;
import org.junit.After;
import org.junit.Test;

import java.util.Set;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CopyOnWriteArraySet;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import static org.hamcrest.core.Is.is;
import static org.hamcrest.core.IsNot.not;
import static org.junit.Assert.assertThat;

public final class ExecutorServiceHandlerRegistryTest {
    
    @After
    public void clear() {
        ExecutorServiceHandlerRegistry.remove("test_job");
    }
    
    @Test
    public void assertRemove() {
        ExecutorService actual = ExecutorServiceHandlerRegistry.getExecutorServiceHandler("test_job", new DefaultExecutorServiceHandler());
        ExecutorServiceHandlerRegistry.remove("test_job");
        assertThat(actual, not(ExecutorServiceHandlerRegistry.getExecutorServiceHandler("test_job", new DefaultExecutorServiceHandler())));
    }
    
    @Test
    public void assertGetExecutorServiceHandlerForSameThread() {
        assertThat(ExecutorServiceHandlerRegistry.getExecutorServiceHandler("test_job", new DefaultExecutorServiceHandler()), 
                is(ExecutorServiceHandlerRegistry.getExecutorServiceHandler("test_job", new DefaultExecutorServiceHandler())));
    }
    
    @Test
    public void assertGetExecutorServiceHandlerForConcurrent() throws InterruptedException {
        int threadCount = 100;
        CyclicBarrier barrier = new CyclicBarrier(threadCount);
        ExecutorService executorService = Executors.newFixedThreadPool(threadCount);
        CountDownLatch latch = new CountDownLatch(threadCount);
        Set<ExecutorService> set = new CopyOnWriteArraySet<>();
        for (int i = 0; i < threadCount; i++) {
            executorService.submit(new GetExecutorServiceHandlerTask(barrier, latch, set));
        }
        latch.await();
        assertThat(set.size(), is(1));
        assertThat(ExecutorServiceHandlerRegistry.getExecutorServiceHandler("test_job", new DefaultExecutorServiceHandler()), is(set.iterator().next()));
    }
    
    @RequiredArgsConstructor
    class GetExecutorServiceHandlerTask implements Runnable {
        
        private final CyclicBarrier barrier;
        
        private final CountDownLatch latch;
        
        private final Set<ExecutorService> set;
        
        @Override
        public void run() {
            try {
                barrier.await();
            } catch (final InterruptedException | BrokenBarrierException ex) {
                ex.printStackTrace();
            }
            set.add(ExecutorServiceHandlerRegistry.getExecutorServiceHandler("test_job", new DefaultExecutorServiceHandler()));
            latch.countDown();
        }
    }
}