droolsexception.java

rule engine drools-2.0-beta-18

package org.drools;

/*
 * $Id: DroolsException.java,v 1.15 2004/11/19 02:12:12 mproctor Exp $
 * 
 * Copyright 2001-2003 (C) The Werken Company. All Rights Reserved.
 * 
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided that the
 * following conditions are met:
 * 
 * 1. Redistributions of source code must retain copyright statements and
 * notices. Redistributions must also contain a copy of this document.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * 3. The name "drools" must not be used to endorse or promote products derived
 * from this Software without prior written permission of The Werken Company.
 * For written permission, please contact [e-mail].
 * 
 * 4. Products derived from this Software may not be called "drools" nor may
 * "drools" appear in their names without prior written permission of The Werken
 * Company. "drools" is a trademark of The Werken Company.
 * 
 * 5. Due credit should be given to The Werken Company. (http://werken.com/)
 * 
 * THIS SOFTWARE IS PROVIDED BY THE WERKEN COMPANY AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE WERKEN COMPANY OR ITS CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *  
 */

import java.io.PrintStream;
import java.io.PrintWriter;

/**
 * Base <code>drools Logic Engine</code> exception.
 * 
 * @author <a href="mailto:[e-mail]">bob mcwhirter </a>
 * 
 * @version $Id: DroolsException.java,v 1.15 2004/11/19 02:12:12 mproctor Exp $
 */
public class DroolsException extends Exception
{
    // ------------------------------------------------------------
    // Instance members
    // ------------------------------------------------------------

    /** Root cause, if any. */
    private Throwable rootCause;

    // ------------------------------------------------------------
    // Constructors
    // ------------------------------------------------------------

    /**
     * Construct.
     */
    public DroolsException()
    {
    }

    /**
     * Construct with a message.
     * 
     * @param msg
     *            The message.
     */
    public DroolsException(String msg)
    {
        super( msg );
    }

    /**
     * Construct with a root cause.
     * 
     * @param rootCause
     *            The root cause of this exception.
     */
    public DroolsException(Throwable rootCause)
    {
        this.rootCause = rootCause;
    }

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

    /**
     * Get the root cause, if any.
     * 
     * @return The root cause of this exception, as a <code>Throwable</code>,
     *         if this exception has a root cause, else <code>null</code>.
     */
    public Throwable getRootCause()
    {
        return this.rootCause;
    }

    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    // java.lang.Exception
    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    /**
     * Retrieve the error message.
     * 
     * @return The error message.
     */
    public String getMessage()
    {
        String selfMessage = super.getMessage( );

        StringBuffer msg = new StringBuffer( );

        if ( selfMessage != null )
        {
            msg.append( selfMessage );
        }

        Throwable rootCause = getRootCause( );

        if ( rootCause != null )
        {
            if ( selfMessage != null )
            {
                msg.append( " : " );
            }

            msg.append( rootCause.getMessage( ) );
        }

        if ( msg.length( ) > 0 )
        {
            return msg.toString( );
        }

        return null;
    }

    /**
     * Retrieve the error message localized to the default locale.
     * 
     * @return The error message.
     */
    public String getLocalizedMessage()
    {
        StringBuffer msg = new StringBuffer( );

        Throwable rootCause = getRootCause( );

        if ( rootCause != null )
        {
            msg.append( rootCause.getLocalizedMessage( ) );
        }
        else
        {
            msg.append( super.getLocalizedMessage( ) );
        }

        if ( msg.length( ) > 0 )
        {
            return msg.toString( );
        }

        return null;
    }

    /**
     * Print the stack trace.
     * 
     * @param s
     *            The output sink.
     */
    public void printStackTrace(PrintStream s)
    {
        super.printStackTrace( s );

        Throwable rootCause = getRootCause( );

        if ( rootCause != null )
        {
            System.err.println( "Nested exception was: " );
            rootCause.printStackTrace( s );
        }
    }

    /**
     * Print the stack trace.
     * 
     * @param s
     *            The output sink.
     */
    public void printStackTrace(PrintWriter s)
    {
        super.printStackTrace( s );

        Throwable rootCause = getRootCause( );

        if ( rootCause != null )
        {
            System.err.println( "Nested exception was: " );
            rootCause.printStackTrace( s );
        }
    }
}