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.facetapi;
021
022import org.apache.isis.applib.filter.Filter;
023import org.apache.isis.applib.filter.Filters;
024
025public final class FacetFilters {
026
027    private FacetFilters() {
028    }
029
030    /**
031     * {@link Filter<Facet>#accept(Facet) Accepts} everything.
032     */
033    public static final Filter<Facet> ANY = Filters.anyOfType(Facet.class);
034    /**
035     * {@link Filter<Facet>#accept(Facet) Accepts} nothing.
036     */
037    public static final Filter<Facet> NONE = new Filter<Facet>() {
038        @Override
039        public boolean accept(final Facet facet) {
040            return false;
041        }
042    };
043
044    public static Filter<Facet> isA(final Class<?> superClass) {
045        return new Filter<Facet>() {
046            @Override
047            public boolean accept(final Facet facet) {
048                if (facet instanceof DecoratingFacet) {
049                    final DecoratingFacet<?> decoratingFacet = (DecoratingFacet<?>) facet;
050                    return accept(decoratingFacet.getDecoratedFacet());
051                }
052                return superClass.isAssignableFrom(facet.getClass());
053            }
054        };
055    }
056}