# StackUnwindException.java

    /*
    ** Module   : StackUnwindException.java
    ** Abstract : used to unwind the stack to the top level block
    **
    ** Copyright (c) 2008-2023, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ----------------Description-----------------
    ** 001 GES 20080513 Created initial version which is used as the
    **                  base class for objects that unwind the stack
    **                  to a specific block.
    ** 002 AIL 20190917 Added constructor to define exception message.
    *  003 IAS 20200723 Reduce stack trace filling overhead
    *  004 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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    **
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    **
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    **     Golden Code Development Corporation, FWD, or any author or contributor to
    **     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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    **     attribution required in this license.
    */

    package com.goldencode.p2j.util;

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

    import java.util.logging.*;

    /**
     * Used to unwind the stack to the nearest enclosing top level block.
     * <p>
     * This class is an unchecked exception because it is used for flow of
     * control (this is required by the lack of closure support in Java combined
     * with the use of inner classes as code blocks). This usage is hidden from
     * the generated code and thus it doesn't make sense to emit
     * <code>throws</code> clauses in the generated code.  In addition there
     * would be no benefit to do so.
     */
    @SuppressWarnings("serial")
    public class StackUnwindException
    extends RuntimeException
    {
       /** Logger */
       private static final CentralLogger LOG = CentralLogger.get(ErrorManager.class.getName());

       /** Flag indicating whether we capture stack trace data */
       private static final boolean captureStack = LOG.isLoggable(Level.FINE);
       /**
        * Default constructor.
        */
       public StackUnwindException()
       {
          super();
       }

       /**
        * Constructor with message initializer
        * @param msg
        *        The message representing this exception
        */
       public StackUnwindException(String msg)
       {
          super(msg);
       }

       /**
        * Fills in the execution stack trace. This method records within this
        * {@code Throwable} object information about the current state of
        * the stack frames for the current thread.
        *
        * <p>If the stack trace of this {@code Throwable} {@linkplain
        * Throwable#Throwable(String, Throwable, boolean, boolean) is not
        * writable}, calling this method has no effect.
        *
        * @return  a reference to this {@code Throwable} instance.
        * @see     java.lang.Throwable#printStackTrace()
        */
       @Override
       public synchronized Throwable fillInStackTrace()
       {
          if (captureStack)
          {
             return super.fillInStackTrace();
          }

          return this;
      }
    }