001/* A marker interface for attributes that replaces any previous instance. 002 003 Copyright (c) 2003-2005 The Regents of the University of California. 004 All rights reserved. 005 Permission is hereby granted, without written agreement and without 006 license or royalty fees, to use, copy, modify, and distribute this 007 software and its documentation for any purpose, provided that the above 008 copyright notice and the following two paragraphs appear in all copies 009 of this software. 010 011 IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY 012 FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES 013 ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF 014 THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF 015 SUCH DAMAGE. 016 017 THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, 018 INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 019 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE 020 PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF 021 CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, 022 ENHANCEMENTS, OR MODIFICATIONS. 023 024 PT_COPYRIGHT_VERSION_2 025 COPYRIGHTENDKEY 026 027 */ 028package ptolemy.kernel.util; 029 030////////////////////////////////////////////////////////////////////////// 031//// Singleton 032 033/** 034 This interface is used to indicate that an attribute is a singleton, 035 meaning that when setContainer() is called, if there is a previous 036 instance of the attribute, then that previous instance is removed. 037 038 @author Edward A. Lee 039 @version $Id$ 040 @since Ptolemy II 4.0 041 @Pt.ProposedRating Green (eal) 042 @Pt.AcceptedRating Green (cxh) 043 */ 044public interface Singleton { 045}