# LockUnavailableException.java

    /*
    ** Module   : LockUnavailableException.java
    ** Abstract : Exception thrown when a lock cannot be acquired for a no-wait lock request
    **
    ** Copyright (c) 2005-2023, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- --JPRM-- ----------------------------Description-----------------------------
    ** 001 ECF 20051207   @23682 Created initial version. An exception thrown
    **                           to indicate that a lock could not be acquired
    **                           for a database record.
    ** 002 ECF 20131028          Moved to lock sub-package.
    ** 003 ECF 20160130          Optimized to not collect stack trace information unless performing
    **                           FINE (or more granular) logging for the lock manager.
    ** 004 ECF 20160812          Added lock type and record identifier information to exception.
    ** 005 GBB 20230512          Logging methods replaced by CentralLogger/ConversionStatus.
    */
    /*
    ** 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
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    **     the covered work, without written authorization.
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    **
    **     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
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    **     Corporation or FWD.  All modified versions must contain the notices of
    **     attribution required in this license.
    */

    package com.goldencode.p2j.persist.lock;

    import java.util.logging.*;
    import com.goldencode.p2j.persist.*;
    import com.goldencode.p2j.util.logging.*;

    /**
     * This exception is thrown by the persistence service layer to indicate that
     * a request to lock a record, issued with the no-wait option, could not be
     * fulfilled, because another user holds the lock.
     * <p>
     * Supports the assignment of an error number at construction.
     */
    public class LockUnavailableException
    extends PersistenceException
    {
       /** Logger */
       private static final CentralLogger LOG = CentralLogger.get(LockManager.class.getName());

       /** Flag indicating whether we capture stack trace data */
       private static final boolean captureStack = LOG.isLoggable(Level.FINE);

       /** Requested lock type which was not acquired */
       private final LockType lockType;

       /** Identifier of record which could not be locked */
       private final RecordIdentifier identifier;

       /**
        * Constructor which accepts an error message only.
        *
        * @param   message
        *          Error message.
        */
       public LockUnavailableException(String message, LockType lockType, RecordIdentifier identifier)
       {
          super(message);

          this.lockType = lockType;
          this.identifier = identifier;
       }

       /**
        * Get the requested lock type.
        *
        * @return  Requested lock type.
        */
       public LockType getLockType()
       {
          return lockType;
       }

       /**
        * Get the record identifier.
        *
        * @return  Record identifier.
        */
       public RecordIdentifier getIdentifier()
       {
          return identifier;
       }

       /**
        * Override the ancestor class' implementation to capture stack trace data only if the lock
        * manager is configured for debug logging. In most cases, we do not actually use the stack
        * trace information when we catch this exception; however, we retain the capability for
        * debugging purposes. For normal production use, where a common use case is to poll for a
        * record lock using the NO-WAIT option in a loop, this implementation does not pay the
        * performance penalty of collecting the data, which is an expensive operation.
        *
        * @return  This exception instance.
        */
       @Override
       public final Throwable fillInStackTrace()
       {
          if (captureStack)
          {
             return super.fillInStackTrace();
          }

          return this;
       }
    }