package gnu.crypto.key;

// ----------------------------------------------------------------------------
// $Id: KeyAgreementException.java,v 1.2 2005/10/20 12:05:01 alexa Exp $
//
// Copyright (C) 2003 Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// GNU Crypto 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
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; see the file COPYING.  If not, write to the
//
//    Free Software Foundation Inc.,
//    51 Franklin Street, Fifth Floor,
//    Boston, MA 02110-1301
//    USA
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library.  Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give
// you permission to link this library with independent modules to
// produce an executable, regardless of the license terms of these
// independent modules, and to copy and distribute the resulting
// executable under terms of your choice, provided that you also meet,
// for each linked independent module, the terms and conditions of the
// license of that module.  An independent module is a module which is
// not derived from or based on this library.  If you modify this
// library, you may extend this exception to your version of the
// library, but you are not obligated to do so.  If you do not wish to
// do so, delete this exception statement from your version.
// ----------------------------------------------------------------------------

import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.Serializable;
import java.security.KeyManagementException;

/**
 * A generic exception indicating that an unexpected condition has been detected
 * during the setup and/or processing of a key agreement protocol exchange.
 *
 * @version $Revision: 1.2 $
 */
public class KeyAgreementException extends KeyManagementException implements Serializable {

   // Constants and variables
   // -------------------------------------------------------------------------

   /** @serial The possibly <code>null</code> <i>root</i> cause exception. */
   private Throwable cause = null;

   // Constructor(s)
   // -------------------------------------------------------------------------

   /**
    * <p>Constructs a new instance of <code>KeyAgreementException</code>. The
    * root exception and the detailed message are <code>null</code>.</p>
    */
   public KeyAgreementException() {
      super();
   }
   /**
    * <p>Constructs a new instance of <code>KeyAgreementException</code> with a
    * detailed message. The <i>root</i> exception is <code>null</code>.</p>
    *
    * @param detail a possibly <code>null</code> string containing details of
    * the exception.
    * @see Throwable#getMessage()
    */
   public KeyAgreementException(String detail) {
      super(detail);
   }

   /**
    * <p>Constructs a new instance of <code>KeyAgreementException</code> with a
    * detailed message and a <i>root</i> exception.</p>
    *
    * @param detail a possibly <code>null</code> string containing details of
    * the exception.
    * @param cause a possibly <code>null</code> root exception that caused this
    * exception.
    * @see Throwable#getMessage()
    * @see #getCause()
    */
   public KeyAgreementException(String detail, Throwable cause) {
      super(detail);
      this.cause = cause;
   }

   // Class methods
   // -------------------------------------------------------------------------

   // Instance methods
   // -------------------------------------------------------------------------

   /**
    * <p>Returns the cause of this throwable or <code>null</code> if the cause
    * is nonexistent or unknown. The <i>cause</i> is the throwable that caused
    * this exception to be thrown.</p>
    *
    * @return the possibly <code>null</code> exception that caused this one.
    */
   public Throwable getCause() {
      return cause;
   }

   /**
    * <p>Prints this exception's stack trace to <code>System.err</code>. If this
    * exception has a <i>root</i> exception; the stack trace of the <i>root</i>
    * exception is also printed to <code>System.err</code>.</p>
    */
   public void printStackTrace() {
      super.printStackTrace();
      if (cause != null) {
         cause.printStackTrace();
      }
   }

   /**
    * <p>Prints this exception's stack trace to a print stream. If this
    * exception has a <i>root</i> exception; the stack trace of the <i>root</i>
    * exception is also printed to the print stream.</p>
    *
    * @param ps the non-null print stream to which to print.
    */
   public void printStackTrace(PrintStream ps) {
      super.printStackTrace(ps);
      if (cause != null) {
         cause.printStackTrace(ps);
      }
   }

   /**
    * <p>Prints this exception's stack trace to a print writer. If this
    * exception has a <i>root</i> exception; the stack trace of the <i>root</i>
    * exception is also printed to the print writer.</p>
    *
    * @param pw the non-null print writer to use for output.
    */
   public void printStackTrace(PrintWriter pw) {
      super.printStackTrace(pw);
      if (cause != null) {
         cause.printStackTrace(pw);
      }
   }

   /**
    * <p>Returns the string representation of this exception. The string
    * representation contains this exception's class name, its detailed
    * messsage, and if it has a <i>root</i> exception, the string representation
    * of the root exception. This string representation is meant for debugging
    * and is not meant to be interpreted programmatically.</p>
    *
    * @return the non-null string representation of this exception.
    * @see Throwable#getMessage()
    */
   public String toString() {
      StringBuffer sb = new StringBuffer(this.getClass().getName())
            .append(": ").append(super.toString());
      if (cause != null) {
         sb.append("; caused by: ").append(cause.toString());
      }
      return sb.toString();
   }
}