# LegacyLogManagerClientServiceImpl.java

    /*
    ** Module   : LegacyLogManagerClientServiceImpl.java
    ** Abstract : LOG-MANAGER client service.
    **
    ** Copyright (c) 2023-2024, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------------Description----------------------------------------
    ** 001 GBB 20230607 Initial setup.
    ** 002 GBB 20240311 Disable permanent file lock.
    ** 003 ICP 20240722 Modified shutdown hook registration.
    */
    /*
    ** 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;

    import com.goldencode.p2j.main.OrderedShutdownHooks;
    import com.goldencode.p2j.util.logging.*;

    import java.io.*;
    import java.nio.*;
    import java.nio.channels.*;
    import java.util.*;
    import java.util.logging.*;

    /** LOG-MANAGER client service. */
    public class LegacyLogManagerClientServiceImpl
    implements LegacyLogManagerClientService
    {
       /** Logger. */
       private static final CentralLogger LOG = CentralLogger.get(LegacyLogManagerClientServiceImpl.class);

       /** The file path. */
       private String filePath;

       /** The output stream to write to the log file. */
       private FileOutputStream fileOutputStream;

       /** The file channel associated with the output stream. */
       private FileChannel channel;

       /** The lock to the file channel, when rotation is enabled. */
       private FileLock rotationLock;

       /**
        * Default public constructor for LegacyLogManagerClientServiceImpl. Adds a JVM shutdown hook to close
        * the log file and release the lock.
        */
       public LegacyLogManagerClientServiceImpl()
       {
          OrderedShutdownHooks.registerShutdownHook(2, new Thread(this::close, getClass().getSimpleName()));
       }

       /**
        * Returns a flag to indicate if the file path is writable.
        *
        * @param     filePath
        *            The file path to check for.
        *
        * @return    <code>true</code> if the folder is writable, <code>false</code> otherwise.
        */
       @Override
       public boolean isWritable(String filePath)
       {
          return LegacyLogManagerImpl.isWritable(new File(filePath));
       }

       /**
        * Receives the clean file path from configs and returns the path modified with rotation number, next in
        * the sequence based on the existing files in the folder.
        *
        * @param     logFileConfig
        *            The clean file path from configs.
        * @param     logThreshold
        *            The size of the file before rolling over.
        *
        * @return    The modified file path with the rotation number.
        */
       @Override
       public String makeSequencedLogFile(String logFileConfig, int logThreshold)
       {
          return LegacyLogManagerImpl.makeSequencedLogFile(logFileConfig, logThreshold).getPath();
       }

       /**
        * Opens the file for writing.
        *
        * @param     filePath
        *            The file path.
        *
        * @return    <code>true</code> if successful, <code>false</code> otherwise.
        */
       @Override
       public boolean open(String filePath)
       {
          if (filePath == null)
          {
             if (this.filePath != null)
             {
                close();
             }
             return true;
          }
          if (filePath.equals(this.filePath))
          {
             return true;
          }
          try
          {
             this.fileOutputStream = new FileOutputStream(filePath, true);
             this.channel = fileOutputStream.getChannel();
             this.filePath = filePath;
          }
          catch (IOException e)
          {
             LOG.log(Level.WARNING, e, "Couldn't open file %s.", filePath);
             return false;
          }
          return true;
       }

       /**
        * Writes the log record.
        *
        * @param     logRecord
        *            The log record.
        *
        * @return    <code>true</code> if successful, <code>false</code> otherwise.
        */
       @Override
       public boolean write(String logRecord)
       {
          if (fileOutputStream == null)
          {
             return false;
          }
          try
          {
             ByteBuffer byteBuffer = ByteBuffer.wrap(logRecord.getBytes());
             if (rotationLock != null)
             {
                channel.write(byteBuffer);
                return true;
             }
             FileLock lock = channel.lock();
             channel.write(byteBuffer);
             lock.release();
             return true;
          }
          catch (Exception e)
          {
             LOG.log(Level.WARNING, e, "Couldn't write log %s to file %s.", logRecord, filePath);
             return false;
          }
       }

       /**
        * Closes the file.
        *
        * @return    <code>true</code> if successful, <code>false</code> otherwise.
        */
       @Override
       public boolean close()
       {
          try
          {
             if (fileOutputStream != null)
             {
                fileOutputStream.flush();
                fileOutputStream.close();
             }
             if (rotationLock != null && rotationLock.isValid())
             {
                rotationLock.release();
             }
             filePath = null;
             channel = null;
             fileOutputStream = null;
          }
          catch (IOException e)
          {
             LOG.log(Level.WARNING, e, "Couldn't close log output stream for file %s.", filePath);
             return false;
          }
          return true;
       }

       /**
        * Clears the content of the currently open log file. If rotation is enabled, deletes all files in the
        * sequence.
        *
        * @return    <code>true</code> if successful, <code>false</code> otherwise.
        */
       @Override
       public boolean clear()
       {
          try
          {
             if (rotationLock == null)
             {
                channel.truncate(0);
             }
             else
             {
                String lastFileName = filePath;
                close();
                return LegacyLogManagerImpl.deleteSequence(new File(lastFileName));
             }
          }
          catch (IOException e)
          {
             LOG.log(Level.WARNING, e, "Couldn't clear the file %s.", filePath);
             return false;
          }
          return true;
       }

       /**
        * Removes the sequenced log files with the same name in the same folder that exceed the max count of
        * numLogFiles, while preserving the current log file and of its predecessors.
        *
        * @param     filePath
        *            The log record.
        * @param     numLogFiles
        *            The log record.
        */
       @Override
       public void cleanupRotation(String filePath, int numLogFiles)
       {
          LegacyLogManagerImpl.cleanupRotation(new File(filePath), numLogFiles);
       }

       /**
        * Writes multiple log record. Used with state transfer.
        *
        * @param     logManagerRecords
        *            The log records.
        */
       public void write(List<String> logManagerRecords)
       {
          if (logManagerRecords == null || logManagerRecords.size() == 0)
          {
             return;
          }
          if (fileOutputStream == null)
          {
             LOG.log(Level.WARNING, "No file open. LOG-MANAGER logs discarded.");
             return;
          }
          FileLock lock = null;
          try
          {
             if (rotationLock == null)
             {
                lock = channel.lock();
             }
             for (String logRecord : logManagerRecords)
             {
                channel.write(ByteBuffer.wrap(logRecord.getBytes()));
             }
          }
          catch (Exception e)
          {
             LOG.log(Level.WARNING, e, "Couldn't write LOG-MANAGER logs to file %s.", filePath);
          }
          finally
          {
             if (lock != null && lock.isValid())
             {
                try
                {
                   lock.release();
                }
                catch (IOException ignored)
                {
                }
             }
          }
       }
    }