/* A marker interface for attributes that extend their container's scope.

 Copyright (c) 2001-2005 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

 @ProposedRating Red (liuxj)
 @AcceptedRating Red (liuxj)

 */
package ptolemy.data.expr;

import java.util.List;

import ptolemy.kernel.util.Attribute;

//////////////////////////////////////////////////////////////////////////
//// ScopeExtender

/**
 A marker interface for attributes that extend their container's scope. Any
 parameter contained by an attribute implementing this interface has the same
 visibility as parameters of the container of the attribute.

 @author Xiaojun Liu
 @version $Id$
 @see ptolemy.data.expr.Variable
 */
public interface ScopeExtender {
    /** Return a list of the attributes contained by this object.
     *  If there are no attributes, return an empty list.
     *  This method is read-synchronized on the workspace.
     *  @return An unmodifiable list of instances of Attribute.
     */
    public List attributeList();

    /** Get the attribute with the given name. The name may be compound,
     *  with fields separated by periods, in which case the attribute
     *  returned is contained by a (deeply) contained attribute.
     *  @param name The name of the desired attribute.
     *  @return The requested attribute if it is found, null otherwise.
     */
    public Attribute getAttribute(String name);
}