JDK14MultithreadedInitializationTest.java

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 * permit persons to whom the Software  is furnished to do so, subject to
 * the following conditions:
 *
 * The  above  copyright  notice  and  this permission  notice  shall  be
 * included in all copies or substantial portions of the Software.
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package org.slf4j.impl;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;

import java.util.List;
import java.util.Random;
import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.atomic.AtomicLong;
import java.util.logging.Handler;
import java.util.logging.LogRecord;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerAccessingThread;
import org.slf4j.LoggerFactory;

public class JDK14MultithreadedInitializationTest {

    final static int THREAD_COUNT = 4 + Runtime.getRuntime().availableProcessors() * 2;

    final private AtomicLong eventCount = new AtomicLong(0);
    final private  CyclicBarrier barrier = new CyclicBarrier(THREAD_COUNT + 1);

    int diff = new Random().nextInt(10000);

    java.util.logging.Logger julRootLogger = java.util.logging.Logger.getLogger("");

    @Before
    public void addRecordingHandler() {
        System.out.println("THREAD_COUNT=" + THREAD_COUNT);
        removeAllHandlersForRoot();
        julRootLogger.addHandler(new RecordingHandler());
    }

    private void removeAllHandlersForRoot() {
        Handler[] handlers = julRootLogger.getHandlers();
        for (int i = 0; i < handlers.length; i++) {
                julRootLogger.removeHandler(handlers[i]);
        }
    }

    @After
    public void tearDown() throws Exception {
        Handler[] handlers = julRootLogger.getHandlers();
        for (int i = 0; i < handlers.length; i++) {
            if (handlers[i] instanceof RecordingHandler) {
                julRootLogger.removeHandler(handlers[i]);
            }
        }
    }

    @Test
    public void multiThreadedInitialization() throws InterruptedException, BrokenBarrierException {
        @SuppressWarnings("unused")
        LoggerAccessingThread[] accessors = harness();

        Logger logger = LoggerFactory.getLogger(getClass().getName());
        logger.info("hello");
        eventCount.getAndIncrement();

        List<LogRecord> records = getRecordedEvents();
        assertEquals(eventCount.get(), records.size());
    }

    private List<LogRecord> getRecordedEvents() {
        RecordingHandler ra = findRecordingHandler();
        if (ra == null) {
            fail("failed to fing RecordingHandler");
        }
        return ra.records;
    }

    private RecordingHandler findRecordingHandler() {
        Handler[] handlers = julRootLogger.getHandlers();
        for (Handler h : handlers) {
            if (h instanceof RecordingHandler)
                return (RecordingHandler) h;
        }
        return null;
    }

    private LoggerAccessingThread[] harness() throws InterruptedException, BrokenBarrierException {
        LoggerAccessingThread[] threads = new LoggerAccessingThread[THREAD_COUNT];
        for (int i = 0; i < THREAD_COUNT; i++) {
            threads[i] = new LoggerAccessingThread(barrier, i, eventCount);
            threads[i].start();
        }

        // trigger barrier
        barrier.await();

        for (int i = 0; i < THREAD_COUNT; i++) {
            threads[i].join();
        }

        return threads;
    }

}