nosuchfacthandleexception.java

rule engine drools-2.0-beta-18

package org.drools;

/*
 * $Id: NoSuchFactHandleException.java,v 1.2 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.
 *
 */

/**
 * Indicates an attempt to retract, modify or retrieve a fact object that is no
 * longer present.
 * 
 * @see FactHandle
 * @see WorkingMemory#getFactHandle
 * 
 * @author <a href="mailto:[e-mail]">Simon Harris </a>
 * 
 * @version $Id: NoSuchFactObjectException.java,v 1.3 2003/11/19 21:31:09 bob
 *          Exp $
 */
public class NoSuchFactHandleException extends FactException
{
    // ----------------------------------------------------------------------
    // Instance members
    // ----------------------------------------------------------------------

    /** Invalid fact object. */
    private final Object object;

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

    public NoSuchFactHandleException()
    {
        this.object = null;
    }

    /**
     * Construct.
     * 
     * @param object
     *            The invalid fact object.
     */
    public NoSuchFactHandleException(Object object)
    {
        this.object = object;
    }

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

    /**
     * Retrieve the invalid Object.
     * 
     * @return The invalid fact object.
     */
    public Object getObject()
    {
        return this.object;
    }

    // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

    /**
     * @see Throwable
     */
    public String getMessage()
    {
        if ( this.object == null )
        {
            return "invalid (null) fact object";
        }

        return "no such fact handle for object: " + object;
    }
}