# CentralSlf4jProvider.java

    /*
    ** Module   : CentralSlf4jProvider.java
    ** Abstract : Implementation of slf4j provider.
    **
    ** Copyright (c) 2024, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ----------------------------Description-----------------------------
    ** 001 GBB 20240422 Initial setup
    ** 002 TJD 20240423 Allow blocking of CentralSlf4jProvider with disableCentralSlf4jProvider
    **                  system property
    ** 003 GBB 20240709 Fixing the javadoc of the constructor.
    ** 004 GBB 20240729 Disable FWD slf4j impl with -DenableSlf4jApi=true jvm arg.
    */
    /*
     ** This program is free software: you can redistribute it and/or modify
     ** it under the terms of the GNU Affero General Public License as
     ** published by the Free Software Foundation, either version 3 of the
     ** License, or (at your option) any later version.
     **
     ** This program is distributed in the hope that it will be useful,
     ** but WITHOUT ANY WARRANTY; without even the implied warranty of
     ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     ** GNU Affero General Public License for more details.
     **
     ** You may find a copy of the GNU Affero GPL version 3 at the following
     ** location: https://www.gnu.org/licenses/agpl-3.0.en.html
     **
     ** Additional terms under GNU Affero GPL version 3 section 7:
     **
     **   Under Section 7 of the GNU Affero GPL version 3, the following additional
     **   terms apply to the works covered under the License.  These additional terms
     **   are non-permissive additional terms allowed under Section 7 of the GNU
     **   Affero GPL version 3 and may not be removed by you.
     **
     **   0. Attribution Requirement.
     **
     **     You must preserve all legal notices or author attributions in the covered
     **     work or Appropriate Legal Notices displayed by works containing the covered
     **     work.  You may not remove from the covered work any author or developer
     **     credit already included within the covered work.
     **
     **   1. No License To Use Trademarks.
     **
     **     This license does not grant any license or rights to use the trademarks
     **     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
     **     of Golden Code Development Corporation. You are not authorized to use the
     **     name Golden Code, FWD, or the names of any author or contributor, for
     **     publicity purposes without written authorization.
     **
     **   2. No Misrepresentation of Affiliation.
     **
     **     You may not represent yourself as Golden Code Development Corporation or FWD.
     **
     **     You may not represent yourself for publicity purposes as associated with
     **     Golden Code Development Corporation, FWD, or any author or contributor to
     **     the covered work, without written authorization.
     **
     **   3. No Misrepresentation of Source or Origin.
     **
     **     You may not represent the covered work as solely your work.  All modified
     **     versions of the covered work must be marked in a reasonable way to make it
     **     clear that the modified work is not originating from Golden Code Development
     **     Corporation or FWD.  All modified versions must contain the notices of
     **     attribution required in this license.
     */
    package com.goldencode.p2j.util.logging;

    import org.slf4j.*;
    import org.slf4j.helpers.*;
    import org.slf4j.spi.*;

    /** Implementation of slf4j provider. */
    public class CentralSlf4jProvider
    implements SLF4JServiceProvider
    {
       /** The custom logger factory. */
       private static final CentralSlf4jLoggerFactory loggerFactory = new CentralSlf4jLoggerFactory();

       /** The default base marker factory. */
       private static IMarkerFactory markerFactory = new BasicMarkerFactory();

       /** The default base mdc adapter. */
       private static MDCAdapter mdcAdapter = new BasicMDCAdapter();

       /**
        * The lowest compatible api version.
        * <p>
        * To avoid constant folding by the compiler, this field must *not* be final
        */
       public static String REQUESTED_API_VERSION = "2.0.0"; // !final

       /**
        * Public constructor, allows preventing instantiation of the provider.
        */
       public CentralSlf4jProvider()
       {
          if (Boolean.parseBoolean(System.getProperty("disableCentralSlf4jProvider", "false")) ||
             Boolean.parseBoolean(System.getProperty(CentralLogger.JVM_ARG_ENABLE_SLF4j_API, "false")))
          {
             // prevent this provider from being instantiated
             throw new RuntimeException("JVM arg `disableCentralSlf4jProvider` or `" +
                                           CentralLogger.JVM_ARG_ENABLE_SLF4j_API +
                                           "` prevents FWD's slf4j implementation to get started.");
          }
       }

       /**
        * Returns the logger factory instance.
        *
        * @return   See above.
        */
       @Override
       public ILoggerFactory getLoggerFactory()
       {
          return loggerFactory;
       }

       /**
        * Return the marker factory instance.
        *
        * @return   See above.
        */
       @Override
       public IMarkerFactory getMarkerFactory()
       {
          return markerFactory;
       }

       /**
        * Returns the mdc adapter instance.
        *
        * @return   See above.
        */
       @Override
       public MDCAdapter getMDCAdapter()
       {
          return mdcAdapter;
       }

       /**
        * Returns the lowest compatible api version.
        *
        * @return   See above.
        */
       @Override
       public String getRequestedApiVersion()
       {
          return REQUESTED_API_VERSION;
       }

       /**
        * Initialization of all factories and adapters needed.
        */
       @Override
       public void initialize()
       {
          // all fields are static final
       }
    }