SLF4J API is a simple API that allows to plug in any desired logging library at deployment time.

Here is the source code for SLF4J API 1.7.31. You can download its pre-compiled version slf4j-api-1.7.31.jar at SLF4J Download Website.

⏎ org/slf4j/helpers/SubstituteLoggerFactory.java

/**
 * Copyright (c) 2004-2011 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
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */
package org.slf4j.helpers;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.LinkedBlockingQueue;

import org.slf4j.ILoggerFactory;
import org.slf4j.Logger;
import org.slf4j.event.SubstituteLoggingEvent;

/**
 * SubstituteLoggerFactory manages instances of {@link SubstituteLogger}.
 *
 * @author Ceki Gülcü
 * @author Chetan Mehrotra
 */
public class SubstituteLoggerFactory implements ILoggerFactory {

    boolean postInitialization = false;
    
    final Map<String, SubstituteLogger> loggers = new HashMap<String, SubstituteLogger>();

    final LinkedBlockingQueue<SubstituteLoggingEvent> eventQueue = new LinkedBlockingQueue<SubstituteLoggingEvent>();

    synchronized public  Logger getLogger(String name) {
        SubstituteLogger logger = loggers.get(name);
        if (logger == null) {
            logger = new SubstituteLogger(name, eventQueue, postInitialization);
            loggers.put(name, logger);
        }
        return logger;
    }

    public List<String> getLoggerNames() {
        return new ArrayList<String>(loggers.keySet());
    }

    public List<SubstituteLogger> getLoggers() {
        return new ArrayList<SubstituteLogger>(loggers.values());
    }

    public LinkedBlockingQueue<SubstituteLoggingEvent> getEventQueue() {
        return eventQueue;
    }

    public void postInitialization() {
    	postInitialization = true;
    }
    
    public void clear() {
        loggers.clear();
        eventQueue.clear();
    }
}

⏎ org/slf4j/helpers/SubstituteLoggerFactory.java

Or download all of them as a single archive file:

File name: slf4j-api-1.7.31-sources.jar
File size: 58728 bytes
Release date: 2021-06-17
Download 

⇒ Source Code for SLF4J 1.7.31 Simple Logging

⇐ Source Code for SLF4J Migrator

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⇑⇑ SLF4J - Simple Logging Facade for Java