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
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** 
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** 
**     This license does not grant any license or rights to use the trademarks
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*/

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;
  }
}