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.facets.object.immutable;
021
022import org.apache.isis.applib.annotation.When;
023import org.apache.isis.applib.events.UsabilityEvent;
024import org.apache.isis.core.metamodel.adapter.ObjectAdapter;
025import org.apache.isis.core.metamodel.facetapi.Facet;
026import org.apache.isis.core.metamodel.facetapi.FacetHolder;
027import org.apache.isis.core.metamodel.facets.WhenValueFacetAbstract;
028import org.apache.isis.core.metamodel.interactions.UsabilityContext;
029
030public abstract class ImmutableFacetAbstract extends WhenValueFacetAbstract implements ImmutableFacet {
031
032    public static Class<? extends Facet> type() {
033        return ImmutableFacet.class;
034    }
035
036    public ImmutableFacetAbstract(final When value, final FacetHolder holder) {
037        super(type(), holder, value);
038    }
039
040    /**
041     * Immutable facet only prevents changes to a property or a collection.
042     */
043    @Override
044    public String disables(final UsabilityContext<? extends UsabilityEvent> ic) {
045        final ObjectAdapter target = ic.getTarget();
046        switch (ic.getInteractionType()) {
047            case PROPERTY_MODIFY:
048            case COLLECTION_ADD_TO:
049            case COLLECTION_REMOVE_FROM:
050                return disabledReason(target);
051            default:
052                return null;
053        }
054    }
055
056    public String disabledReason(final ObjectAdapter targetAdapter) {
057        if (when() == When.ALWAYS) {
058            return "Always immmutable";
059        } else if (when() == When.NEVER) {
060            return null;
061        }
062
063        // remaining tests depend on target in question.
064        if (targetAdapter == null) {
065            return null;
066        }
067
068        if (when() == When.UNTIL_PERSISTED) {
069            return targetAdapter.isTransient() ? "Immutable until persisted" : null;
070        } else if (when() == When.ONCE_PERSISTED) {
071            return targetAdapter.representsPersistent() ? "Immutable once persisted" : null;
072        }
073        return null;
074    }
075
076}