001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *        http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 */
019
020package org.apache.isis.core.metamodel.spec.feature;
021
022import org.apache.isis.core.metamodel.adapter.ObjectAdapter;
023
024/**
025 * Mix-in interface for {@link ObjectFeature}s that reference or otherwise
026 * contain a 'current' value.
027 * 
028 * <p>
029 * Examples include {@link OneToOneAssociation properties},
030 * {@link OneToManyAssociation collection}s and {@link OneToOneActionParameter
031 * action parameter}s (but not {@link ObjectAction action}s themselves).
032 */
033public interface CurrentHolder {
034
035    /**
036     * Returns the referenced {@link ObjectAdapter} for the owning
037     * {@link ObjectAdapter}.
038     * 
039     * <p>
040     * For example, if this is an {@link OneToOneAssociation}, then returns the
041     * referenced object.
042     */
043    ObjectAdapter get(final ObjectAdapter owner);
044
045}