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.adapter;
021
022import org.apache.isis.core.metamodel.interactions.ProposedHolder;
023import org.apache.isis.core.metamodel.spec.Instance;
024import org.apache.isis.core.metamodel.spec.Specification;
025
026/**
027 * Mix-in for {@link Instance} implementations, where can hold a proposed new
028 * value different from the underlying value.
029 * 
030 * <p>
031 * TODO: same concept as {@link ProposedHolder}, so should try to combine.
032 */
033public interface MutableProposedHolder {
034
035    /**
036     * The proposed (pending) value, if applicable.
037     * 
038     * <p>
039     * See {@link Specification#createInstanceProposalEvent(Instance)} for an
040     * indication as to whether the state will be populated, and what its type
041     * will be.
042     * 
043     * @return
044     */
045    Object getProposed();
046
047    /**
048     * Sets the proposed (pending) value, if applicable.
049     * 
050     * <p>
051     * <p>
052     * See {@link Specification#createInstanceProposalEvent(Instance)} for an
053     * indication as to whether the proposed state should be populated, and what
054     * its type will be.
055     * 
056     * @return
057     */
058    public void setProposed(Object value);
059
060}