/* Class representing a type change for one Typeable object.

 Copyright (c) 1998-2014 The Regents of the University of California.
 All rights reserved.
 Permission is hereby granted, without written agreement and without
 license or royalty fees, to use, copy, modify, and distribute this
 software and its documentation for any purpose, provided that the above
 copyright notice and the following two paragraphs appear in all copies
 of this software.

 IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
 THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
 SUCH DAMAGE.

 THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
 PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
 CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
 ENHANCEMENTS, OR MODIFICATIONS.

 PT_COPYRIGHT_VERSION_2
 COPYRIGHTENDKEY

 */
package ptolemy.actor;

import ptolemy.data.type.Type;
import ptolemy.data.type.Typeable;
import ptolemy.kernel.util.DebugEvent;
import ptolemy.kernel.util.NamedObj;

///////////////////////////////////////////////////////////////////
//// TypeEvent

/**
 A TypeEvent represents a type change on a Typeable object.  This event is
 generated by the Typeable whose type is changed, and is passed to the type
 change listeners to notify them about the change.

 @author Yuhong Xiong
 @version $Id: TypeEvent.java 70398 2014-10-22 23:44:32Z cxh $
 @since Ptolemy II 0.2
 @Pt.ProposedRating Green (yuhong)
 @Pt.AcceptedRating Green (cxh)
 @see TypeListener
 */
public class TypeEvent implements DebugEvent {
    ///////////////////////////////////////////////////////////////////
    ////                         constructors                      ////

    /** Construct a TypeEvent, with the specified Typeable and the
     *  old and new types.
     *  @param typeable The Typeable whose type is changed.
     *  @param oldType The type of the Typeable before the change.
     *  @param newType The type of the Typeable after the change.
     */
    public TypeEvent(Typeable typeable, Type oldType, Type newType) {
        _typeable = typeable;
        _oldType = oldType;
        _newType = newType;
    }

    ///////////////////////////////////////////////////////////////////
    ////                         public methods                    ////

    /** Return the new type.
     *  @return The type of the Typeable after the change.
     */
    public Type getNewType() {
        return _newType;
    }

    /** Return the old type.
     *  @return The type of the Typeable before the change.
     */
    public Type getOldType() {
        return _oldType;
    }

    /** Return the Typeable whose type is changed.
     *  @return The Typeable whose type is changed.
     */
    @Override
    public NamedObj getSource() {
        return (NamedObj) _typeable;
    }

    /** Return a string description for this type change. The string
     *  is "The type on <i>typeable</i> has changed from <i>old
     *  type</i> to <i>new type</i>", where <i>typeable</i> is the
     *  name of the Typeable, and <i>old type</i> and <i>new type</i>
     *  are the string representation of the types.
     *  @return A string description for this type change.
     */
    @Override
    public String toString() {
        return "The type on " + getSource().getFullName() + " has changed "
                + "from " + _oldType.toString() + " to " + _newType.toString();
    }

    ///////////////////////////////////////////////////////////////////
    ////                       private fields                    ////
    private Typeable _typeable;

    private Type _oldType;

    private Type _newType;
}