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.progmodel.facetdecorators.help;
021
022import org.apache.isis.applib.Identifier;
023import org.apache.isis.core.metamodel.facetapi.Facet;
024import org.apache.isis.core.metamodel.facetapi.FacetHolder;
025import org.apache.isis.core.metamodel.facetapi.IdentifiedHolder;
026import org.apache.isis.core.metamodel.facetdecorator.FacetDecoratorAbstract;
027import org.apache.isis.core.metamodel.facets.help.HelpFacet;
028
029public class HelpFacetDecoratorUsingHelpManager extends FacetDecoratorAbstract implements HelpFacetDecorator {
030    private final HelpManager helpManager;
031
032    public HelpFacetDecoratorUsingHelpManager(final HelpManager manager) {
033        helpManager = manager;
034    }
035
036    @Override
037    public Facet decorate(final Facet facet, final FacetHolder facetHolder) {
038        if (facet.facetType() != HelpFacet.class) {
039            return facet;
040        }
041
042        if (!(facetHolder instanceof IdentifiedHolder)) {
043            return null;
044        }
045
046        final IdentifiedHolder identifiedHolder = (IdentifiedHolder) facetHolder;
047        return decorateWithHelpFacet(facet, identifiedHolder);
048    }
049
050    private Facet decorateWithHelpFacet(final Facet facet, final IdentifiedHolder identifiedHolder) {
051        final Identifier identifier = identifiedHolder.getIdentifier();
052
053        final String helpText = helpManager.getHelpText(identifier);
054        if (helpText != null) {
055            final HelpFacetLookedUpViaHelpManager decoratingFacet = new HelpFacetLookedUpViaHelpManager(helpText, facet.getFacetHolder());
056            identifiedHolder.addFacet(decoratingFacet);
057            return decoratingFacet;
058        }
059        return null;
060    }
061
062    @Override
063    @SuppressWarnings("unchecked")
064    public Class<? extends Facet>[] getFacetTypes() {
065        return new Class[] { HelpFacet.class };
066    }
067}