slf4j-simple/src/test/java/org/slf4j/simple/multiThreadedExecution/MultithereadedExecutionTest.java

/**
 * Copyright (c) 2004-2021 QOS.ch
 * All rights reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to  deal in  the Software without  restriction, including
 * without limitation  the rights to  use, copy, modify,  merge, publish,
 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
 * 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.
 *
 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
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package org.slf4j.simple.multiThreadedExecution;

import java.io.PrintStream;

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

/**
 * Tests that output in multithreaded environments is not mingled.
 * 
 * See also https://jira.qos.ch/browse/SLF4J-515
 */
public class MultithereadedExecutionTest {

    private static final int THREAD_COUNT = 2;
    private final Thread[] threads = new Thread[THREAD_COUNT];

    private static final long TEST_DURATION_IN_MILLIS = 100;
    
    private final PrintStream oldOut = System.out;
    StateCheckingPrintStream scps = new StateCheckingPrintStream(oldOut);

    volatile boolean signal = false;

    @Before
    public void setup() {
        System.setErr(scps);
        // System.setProperty(SimpleLogger.LOG_FILE_KEY, "System.err");
        // LoggerFactoryFriend.reset();
    }

    @After
    public void tearDown() throws Exception {
        // LoggerFactoryFriend.reset();
        // System.clearProperty(SimpleLogger.LOG_FILE_KEY);
        System.setErr(oldOut);
    }

    @Test
    public void test() throws Throwable {
        WithException withException = new WithException();
        Other other = new Other();
        threads[0] = new Thread(withException);
        threads[1] = new Thread(other);
        threads[0].start();
        threads[1].start();
        Thread.sleep(TEST_DURATION_IN_MILLIS);
        signal = true;
        threads[0].join();
        threads[1].join();

        if (withException.throwable != null) {
            throw withException.throwable;
        }

        if (other.throwable != null) {
            throw other.throwable;
        }

    }

    class WithException implements Runnable {

        volatile Throwable throwable;
        Logger logger = LoggerFactory.getLogger(WithException.class);

        @Override
        public void run() { // TODO Auto-generated method stub
            int i = 0;

            while (!signal) {
                try {
                    logger.info("Hello {}", i, new Throwable("i=" + i));
                    i++;
                } catch (Throwable t) {
                    throwable = t;
                    MultithereadedExecutionTest.this.signal = true;
                    return;
                }
            }

        }
    }

    class Other implements Runnable {
        volatile Throwable throwable;
        Logger logger = LoggerFactory.getLogger(Other.class);

        @Override
        public void run() {
            int i = 0;
            while (!signal) {
                try {
                    logger.info("Other {}", i++);
                } catch (Throwable t) {
                    throwable = t;
                    MultithereadedExecutionTest.this.signal = true;
                    return;
                }
            }
        }
    }

}